cover.erl

%%
%% %CopyrightBegin%
%%
%% Copyright Ericsson AB 2001-2024. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%
%% %CopyrightEnd%
%%
-module(cover).
-moduledoc """
A Coverage Analysis Tool for Erlang

The module `cover` provides a set of functions for coverage analysis
of Erlang programs, counting how many times each _executable line_ of
code is executed when a program is run. Executable lines are
lines in the body of a clause in a function, `case`,
`receive`, or `try`. Lines in clause heads, blank lines, and lines
containing only comments are not executable.

Coverage analysis can be used to verify that test cases covers all
relevant line in the code being test. It can also be helpful when
looking for bottlenecks in the code.

Before any analysis can take place, the involved modules has to be
_cover-compiled_.  This means that some extra information is added to
the module before it is compiled into a binary which then is
loaded. The source file of the module is not affected and no `.beam`
file is created. If the runtime system supports coverage natively,
Cover will automatically use that functionality to lower the execution
overhead for cover-compiled code.

> #### Change {: .info }
>
> Native coverage support was added in Erlang/OTP 27.

Each time a function in a cover-compiled module is called, information about the
call is added to an internal database of Cover. The coverage analysis is
performed by examining the contents of the Cover database. The output `Answer`
is determined by two parameters: `Level` and `Analysis`.

- `Level = module`

  `Answer = {Module,Value}`, where `Module` is the module name.

- `Level = function`

  `Answer = [{Function,Value}]`, one tuple for each function in the module. A
  function is specified by its module name `M`, function name `F` and arity `A`
  as a tuple `{M,F,A}`.

- `Level = clause`

  `Answer = [{Clause,Value}]`, one tuple for each clause in the module. A clause
  is specified by its module name `M`, function name `F`, arity `A` and position
  in the function definition `C` as a tuple `{M,F,A,C}`.

- `Level = line`

  `Answer = [{Line,Value}]`, one tuple for each executable line in the module. A
  line is specified by its module name `M` and line number in the source file
  `N` as a tuple `{M,N}`.

- `Analysis = coverage`

  `Value = {Cov,NotCov}` where `Cov` is the number of executable lines in the
  module, function, clause or line that have been executed at least once and
  `NotCov` is the number of executable lines that have not been executed.

- `Analysis = calls`

  `Value = Calls` which is the number of times the module, function, or clause
  has been called. In the case of line level analysis, `Calls` is the number of
  times the line has been executed.

### Distribution

Cover can be used in a distributed Erlang system. One of the nodes in the system
has to be selected as the _main node_, and all Cover commands must be
executed from that node. The error reason `not_main_node` is returned if an
interface function is called on one of the remote nodes.

Use `cover:start/1` and `cover:stop/1` to add or remove nodes. The
same cover-compiled code will be loaded on each node, and analysis
will collect and sum up coverage data results from all nodes.

To only collect data from remote nodes without stopping `cover` on those nodes,
use `cover:flush/1`

If the connection to a remote node goes down, the main node will mark it as
lost. If the node comes back it will be added again. If the remote node was
alive during the disconnected period, cover data from before and during this
period will be included in the analysis.
""".

%%
%% This module implements the Erlang coverage tool.
%%
%% ARCHITECTURE
%%
%% The coverage tool consists of one process on each node involved in
%% coverage analysis. The process is registered as 'cover_server'
%% (?SERVER).  The cover_server on the 'main' node is in charge, and
%% it monitors the cover_servers on all remote nodes. When it gets a
%% 'DOWN' message for another cover_server, it marks the node as
%% 'lost'. If a nodeup is received for a lost node the main node
%% ensures that the cover compiled modules are loaded again. If the
%% remote node was alive during the disconnected period, cover data
%% for this period will also be included in the analysis.
%%
%% The cover_server process on the main node is implemented by the
%% functions init_main/1 and main_process_loop/1. The cover_server on
%% the remote nodes are implemented by the functions init_remote/2 and
%% remote_process_loop/1.
%%
%% COUNTERS
%%
%% The 'counters' modules is used for counting how many time each line
%% executed. Each cover-compiled module will have its own array of
%% counters.
%%
%% The counter reference for module Module is stored in a persistent
%% term with the key {cover,Module}.
%%
%% When the cover:local_only/0 function has been called, the reference
%% for the counter array will be compiled into each cover-compiled
%% module directly (instead of retrieving it from a persistent term).
%% That will be faster, but the resulting code can be only be used on
%% the main node.
%%
%% TABLES
%%
%% Each node has one table: ?COVER_MAPPING_TABLE.
%%
%% ?COVER_MAPPING_TABLE maps from a #bump{} record to an index in the
%% counter array for the module. It is used both during instrumentation
%% of cover-compiled modules and when collecting the counter values.
%%
%% The main node owns the table ?COLLECTION_TABLE. The counter data
%% is consolidated into this table from the counters on both the main
%% node and from remote nodes. This consolidation is done when a
%% remote node is stopped with cover:stop/1 or just before starting an
%% analysis.
%%
%% The main node also has a table named ?BINARY_TABLE. This table
%% contains the abstract code code for each cover-compiled
%% module. This is necessary so that the code can be loaded on remote
%% nodes that are started after the compilation.
%%
%% PARALLELISM
%%
%% To take advantage of SMP when doing the cover analysis both the data 
%% collection and analysis has been parallelized. One process is spawned for
%% each node when collecting data, and on the remote node when collecting data
%% one process is spawned per module. 
%% 
%% When analyzing data it is possible to issue multiple
%% analyse(_to_file)/X calls at once. They are, however, all calls
%% (for backwards compatibility reasons), so the user of cover will
%% have to spawn several processes to to the calls (or use
%% async_analyse_to_file/X).
%%

%% External exports
-export([start/0, start/1,
	 compile/1, compile/2, compile_module/1, compile_module/2,
	 compile_directory/0, compile_directory/1, compile_directory/2,
	 compile_beam/1, compile_beam_directory/0, compile_beam_directory/1,
	 analyse/0, analyse/1, analyse/2, analyse/3,
	 analyze/0, analyze/1, analyze/2, analyze/3,
	 analyse_to_file/0,
	 analyse_to_file/1, analyse_to_file/2, analyse_to_file/3,
	 analyze_to_file/0,
	 analyze_to_file/1, analyze_to_file/2, analyze_to_file/3,
	 async_analyse_to_file/1,async_analyse_to_file/2,
	 async_analyse_to_file/3, async_analyze_to_file/1,
	 async_analyze_to_file/2, async_analyze_to_file/3,
	 export/1, export/2, import/1,
	 modules/0, imported/0, imported_modules/0, which_nodes/0, is_compiled/1,
	 reset/1, reset/0,
	 flush/1,
	 stop/0, stop/1,
         local_only/0]).
-export([remote_start/1,get_main_node/0]).

%% Used internally to ensure we upgrade the code to the latest version.
-export([main_process_loop/1,remote_process_loop/1]).

-record(main_state, {compiled=[],           % [{Module,File}]
		     imported=[],           % [{Module,File,ImportFile}]
		     stopper,               % undefined | pid()
                     local_only=false,      % true | false
		     nodes=[],              % [Node]
		     lost_nodes=[]}).       % [Node]

-record(remote_data, {module,
                      file,
                      code,
                      mapping,
                      clauses}).

-record(remote_state, {compiled=[],         % [{Module,File}]
		       main_node}).         % atom()

-record(bump, {module   = '_',              % atom()
	       function = '_',              % atom()
	       arity    = '_',              % integer()
	       clause   = '_',              % integer()
	       line     = '_'               % integer()
	      }).
-define(BUMP_REC_NAME,bump).
-define(CHUNK_SIZE, 20000).

-define(COVER_MAPPING_TABLE, 'cover_internal_mapping_table').
-define(BINARY_TABLE, 'cover_binary_code_table').
-define(COLLECTION_TABLE, 'cover_collected_remote_data_table').

-define(TAG, cover_compiled).
-define(SERVER, cover_server).

-define(SPAWN_DBG(Tag,Value),put(Tag,Value)).
-define(STYLESHEET, "styles.css").
-define(TOOLS_APP, tools).

-include_lib("stdlib/include/ms_transform.hrl").

%%%----------------------------------------------------------------------
%%% External exports
%%%----------------------------------------------------------------------

-doc """
Starts the Cover server which owns the Cover internal database. This function is
called automatically by the other functions in the module.
""".
-spec start() -> {'ok', pid()} | {'error', Reason} when
      Reason :: {'already_started', pid()}
              | term().

start() ->
    case whereis(?SERVER) of
	undefined ->
	    Starter = self(),
	    Pid = spawn(fun() -> 
				?SPAWN_DBG(start,[]),
				init_main(Starter) 
			end),
	    Ref = erlang:monitor(process,Pid),
	    Return = 
		receive 
		    {?SERVER,started} -> 
			{ok,Pid};
		    {?SERVER,{error,Error}} -> 
			{error,Error};
		    {'DOWN', Ref, _Type, _Object, Info} -> 
			{error,Info}
		end,
	    erlang:demonitor(Ref),
	    Return;
	Pid ->
	    {error,{already_started,Pid}}
    end.

-doc """
Starts a Cover server on the each of given nodes, and loads all cover compiled
modules.

This call will fail if `cover:local_only/0` has been called.
""".
-spec start(Nodes) -> {'ok', StartedNodes}
                    | {'error', 'not_main_node'}
                    | {'error', 'local_only'} when
      Nodes :: node() | [node()],
      StartedNodes :: [node()].

start(Node) when is_atom(Node) ->
    start([Node]);
start(Nodes) ->
    call({start_nodes,remove_myself(Nodes,[])}).

-doc """
Only support running Cover on the local node.

This function has to be called before any modules have been compiled or
any nodes added. When running in this mode, modules will be
cover-compiled in a more efficient way, but the resulting code will
only work on the same node they were compiled on.
""".
-doc(#{since => <<"OTP 22.0">>}).
-spec local_only() -> 'ok' | {'error', 'too_late'}.

local_only() ->
    call(local_only).

-type compile_result() :: {'ok', Module :: module()}
                        | {'error', file:filename()}
                        | {'error', 'not_main_node'}.
-type mod_file() :: (Module :: module()) | (File :: file:filename()).
-type mod_files() :: mod_file() | [mod_file()].
-type option() :: {'i', Dir :: file:filename()}
                | {'d', Macro :: atom()}
                | {'d', Macro :: atom(), Value :: term()}
                | 'export_all'.

-doc #{equiv => compile_module(ModFiles, [])}.
-spec compile(ModFiles) -> Result | [Result] when
      ModFiles :: mod_files(),
      Result :: compile_result().

compile(ModFile) ->
    compile_module(ModFile, []).

-doc #{equiv => compile_module(ModFile, Options)}.
-spec compile(ModFiles, Options) -> Result | [Result] when
      ModFiles :: mod_files(),
      Options :: [option()],
      Result :: compile_result().

compile(ModFile, Options) ->
    compile_module(ModFile, Options).

-doc(#{equiv => compile_module(ModFile, [])}).
-spec compile_module(ModFiles) -> Result | [Result] when
      ModFiles :: mod_files(),
      Result :: compile_result().

compile_module(ModFile) when is_atom(ModFile);
			     is_list(ModFile) ->
    compile_module(ModFile, []).

-doc """
Cover-compiles one or more modules.

The module is given by its module name `Module` or by its file name
`File`.

The `.erl` extension can be omitted. If the module is not located in
the current directory, the full path to it must be specified.

`Options` is a list of compiler options. Only options defining include
file directories and macros are passed to `compile:file/2`;
everything else is ignored.

If the module is successfully cover-compiled, the function returns
`{ok, Module}`. Otherwise the function returns `{error, File}`. Errors and
warnings are printed as they occur.

If a list of `ModFiles` is given as input, a list of [`Result`](`t:compile_result/0`)
will be returned. The order of the returned results in the list is undefined.

Note that the internal database is initialized during the compilation,
which means that any previously collected coverage data for the module
is lost.
""".
-spec compile_module(ModFiles, Options) -> Result | [Result] when
      ModFiles :: mod_files(),
      Options :: [option()],
      Result :: compile_result().

compile_module(ModFile, Options) when is_atom(ModFile);
				      is_list(ModFile), is_integer(hd(ModFile)) ->
    [R] = compile_module([ModFile], Options),
    R;
compile_module(ModFiles, Options) when is_list(Options) ->
    AbsFiles =
	[begin
	     File =
		 case ModFile of
		     _ when is_atom(ModFile) -> atom_to_list(ModFile);
		     _ when is_list(ModFile) -> ModFile
		 end,
	     WithExt = case filename:extension(File) of
			   ".erl" ->
			       File;
			   _ ->
			       File++".erl"
		       end,
	     filename:absname(WithExt)
	 end || ModFile <- ModFiles],
    compile_modules(AbsFiles, Options).

-type file_error() :: 'eacces' | 'enoent'.

-doc #{equiv => compile_directory(".", [])}.
-spec compile_directory() -> [Result] | {'error', Reason} when
      Reason :: file_error(),
      Result :: compile_result().

compile_directory() ->
    case file:get_cwd() of
	{ok, Dir} ->
	    compile_directory(Dir, []);
	Error ->
	    Error
    end.

-doc #{equiv => compile_directory(Dir, [])}.
-spec compile_directory(Dir) -> [Result] | {'error', Reason} when
      Dir :: file:filename(),
      Reason :: file_error(),
      Result :: compile_result().

compile_directory(Dir) when is_list(Dir) ->
    compile_directory(Dir, []).


-doc """
Compiles all modules (`.erl` files) in a directory `Dir` for Cover analysis the
same way as [`compile_module/1,2`](`compile_module/1`) and returns a list of
[`Result`](`t:compile_result/0`).

This function returns `{error, eacces}` if the directory is not readable or
`{error, enoent}` if the directory does not exist.
""".
-spec compile_directory(Dir, Options) -> [Result] | {'error', Reason} when
      Dir :: file:filename(),
      Options :: [option()],
      Reason :: file_error(),
      Result :: compile_result().

compile_directory(Dir, Options) when is_list(Dir), is_list(Options) ->
    case file:list_dir(Dir) of
	{ok, Files} ->
	    ErlFiles = [filename:join(Dir, File) ||
			   File <- Files,
			   filename:extension(File) =:= ".erl"],
	    compile_modules(ErlFiles, Options);
	Error ->
	    Error
    end.

compile_modules(Files,Options) ->
    Options2 = filter_options(Options),
    call({compile, Files, Options2}).

filter_options(Options) ->
    lists:filter(fun(Option) ->
                         case Option of
                             {i, Dir} when is_list(Dir) -> true;
                             {d, _Macro} -> true;
                             {d, _Macro, _Value} -> true;
                             export_all -> true;
                             tuple_calls -> true;
                             {feature,_,enable} -> true; %FIXME: To be removed.
                             {feature,_,disable} -> true; %FIXME: To be removed.
                             _ -> false
                         end
                 end,
                 Options).

-type beam_mod_file() :: (Module :: module()) | (BeamFile :: file:filename()).
-type beam_mod_files() :: beam_mod_file() | [beam_mod_file()].
-type compile_beam_rsn() ::
        'non_existing'
      | {'no_abstract_code', BeamFile :: file:filename()}
      | {'encrypted_abstract_code', BeamFile :: file:filename()}
      | {'already_cover_compiled', 'no_beam_found', module()}
      | {{'missing_backend', module()}, BeamFile :: file:filename()}
      | {'no_file_attribute', BeamFile :: file:filename()}
      | 'not_main_node'.

-type compile_beam_result() :: {'ok', module()}
                             | {'error', BeamFile :: file:filename()}
                             | {'error', Reason :: compile_beam_rsn()}.

-doc """
Cover-compiles one or more modules based `.beam` files containing
abstract code (option `debug_info`).

Cover-compiling from `.beam` files is faster than compiling from
source and less hassle, because there is no need to supply options for
include paths or macros. However, the existing `.beam` files must have
been compiled with option
[`debug_info`](`e:compiler:compile.md#debug_info`) so that they contain
[*abstract code*](`e:erts:absform`).

If abstract code is missing, the error reason `{no_abstract_code,
BeamFile}` is returned. If the abstract code is encrypted, and no key
is available for decrypting it, the error reason
`{encrypted_abstract_code, BeamFile}` is returned.

If only the module name (that is, not the full name of the `.beam`
file) is given to this function, the `.beam` file is found by calling
[`code:which(Module)`](`code:which/1`). If no `.beam` file is found,
the error reason `non_existing` is returned. If the module is already
cover compiled with [`compile_beam/1`](`compile_beam/1`), the `.beam`
file will be picked from the same location as the first time it was
compiled. If the module is already cover-compiled with
`compile_module/2`, there is no way to find the correct `.beam` file,
so the error reason `{already_cover_compiled, no_beam_found, Module}`
is returned.

`{error, BeamFile}` is returned if the compiled code cannot be loaded on the
node.

If a list of `ModFiles` is given as input, a list of `Result` will be returned.
The order of the returned list is undefined.
""".
-spec compile_beam(ModFiles) -> Result | [Result] when
      ModFiles :: beam_mod_files(),
      Result :: compile_beam_result().

compile_beam(ModFile0) when is_atom(ModFile0);
			    is_list(ModFile0), is_integer(hd(ModFile0)) ->
    case compile_beams([ModFile0]) of
	[{error,{non_existing,_}}] ->
	    %% Backwards compatibility
	    {error,non_existing};
	[Result] ->
	    Result
    end;
compile_beam(ModFiles) when is_list(ModFiles) ->
    compile_beams(ModFiles).

-doc(#{equiv => compile_beam_directory(".")}).
-spec compile_beam_directory() -> [Result] | {'error', Reason} when
      Reason :: file_error(),
      Result :: compile_beam_result().

compile_beam_directory() ->
    case file:get_cwd() of
	{ok, Dir} ->
	    compile_beam_directory(Dir);
	Error ->
	    Error
    end.

-doc """
Cover-compiles all `.beam` files in directory `Dir` in the same way
as `compile_beam/1`.

This function returns a list of [`compile_beam_result()`](`t:compile_beam_result/0`)
if successful. Otherwise, it returns  `{error, eacces}` if the directory is not
readable, and `{error, enoent}` if the directory does not exist.
""".
-spec compile_beam_directory(Dir) ->
                    [Result] | {'error', Reason} when
      Dir :: file:filename(),
      Reason :: file_error(),
      Result :: compile_beam_result().

compile_beam_directory(Dir) when is_list(Dir) ->
    case file:list_dir(Dir) of
	{ok, Files} ->
            BeamFiles = [filename:join(Dir, File) ||
                            File <- Files,
                            filename:extension(File) =:= ".beam"],
	    compile_beams(BeamFiles);
	Error ->
	    Error
    end.

compile_beams(ModFiles0) ->
    ModFiles = get_mods_and_beams(ModFiles0,[]),
    call({compile_beams,ModFiles}).

get_mods_and_beams([Module|ModFiles],Acc) when is_atom(Module) ->
    case code:which(Module) of
	non_existing ->
	    get_mods_and_beams(ModFiles,[{error,{non_existing,Module}}|Acc]);
	File ->
	    get_mods_and_beams([{Module,File}|ModFiles],Acc)
    end;
get_mods_and_beams([File|ModFiles],Acc) when is_list(File) ->
    {WithExt,WithoutExt}
	= case filename:rootname(File,".beam") of
	      File ->
		  {File++".beam",File};
	      Rootname ->
		  {File,Rootname}
	      end,
    AbsFile = filename:absname(WithExt),
    Module = list_to_atom(filename:basename(WithoutExt)),
    get_mods_and_beams([{Module,AbsFile}|ModFiles],Acc);
get_mods_and_beams([{Module,File}|ModFiles],Acc) ->
    %% Check for duplicates
    case lists:keyfind(Module,2,Acc) of
	{ok,Module,File} ->
	    %% Duplicate, but same file so ignore
	    get_mods_and_beams(ModFiles,Acc);
	{ok,Module,_OtherFile} ->
	    %% Duplicate and different file - error
	    get_mods_and_beams(ModFiles,[{error,{duplicate,Module}}|Acc]);
	_ ->
	    get_mods_and_beams(ModFiles,[{ok,Module,File}|Acc])
    end;
get_mods_and_beams([],Acc) ->
    lists:reverse(Acc).

-type analyse_item() ::
        (Line :: {M :: module(), N :: non_neg_integer()})
      | (Clause :: {M :: module(), F :: atom(), A :: arity(),
                    C :: non_neg_integer()})
      | (Function :: {M :: module(), F :: atom(), A :: arity()}). % mfa()
-type analyse_value() :: {Cov :: non_neg_integer(), NotCov :: non_neg_integer()}
                       | Calls :: non_neg_integer().
-type analyse_ok() :: [{Module :: module(), Value :: analyse_value()}]
                    | [{Item :: analyse_item(), Value :: analyse_value()}].
-type analyse_fail() :: [{'not_cover_compiled', module()}].
-type analysis() :: 'coverage' | 'calls'.
-type level() :: 'line' | 'clause' | 'function' | 'module'.
-type modules() :: module() | [module()].
-type one_result() ::
        {'ok', {Module :: module(), Value :: analyse_value()}}
      | {'ok', [{Item :: analyse_item(), Value :: analyse_value()}]}
      | {'error', {'not_cover_compiled', module()}}.

-define(is_analysis(__A__),
	(__A__=:=coverage orelse __A__=:=calls)).
-define(is_level(__L__),
	(__L__=:=line orelse __L__=:=clause orelse
	 __L__=:=function orelse __L__=:=module)).

-doc #{equiv => analyse('_', coverage, function),
       since => <<"OTP 18.0">>}.
-spec analyse() -> {'result', analyse_ok(), analyse_fail()} |
                   {'error', 'not_main_node'}.

analyse() ->
    analyse('_').

-dialyzer({no_contracts, analyse/1}).
-doc """
analyse(Arg)

Analyzes one or more modules as specified by `Arg`.

If `Arg` is one of the values in [`analysis()`](`t:analysis/0`), this
call is equivalent to [`analyse('_', Arg, function)`](`analyse/3`).

If `Arg` is one of the values in [`level()`](`t:level/0`), this
call is equivalent to [`analyse('_', coverage, Arg)`](`analyse/3`).

Otherwise `Arg` is assumed to be a module name, and this call is equivalent
to [`analyse(Arg, coverage, function)`](`analyse/3`).

> #### Note {: .info }
>
> To analyze a module whose name overlaps with one the values in
> [`analysis()`](`t:analysis/0`) or [`level()`](`t:level/0`), the module
> name has to be in a list. For example, to analyze a module named `calls`:
>
> ```
> cover:analyse([calls]).
> ```
""".
-spec analyse(Analysis) -> {'result', analyse_ok(), analyse_fail()} |
                           {'error', 'not_main_node'} when
                  Analysis :: analysis();
             (Level) -> {'result', analyse_ok(), analyse_fail()} |
                        {'error', 'not_main_node'} when
                  Level :: level();
             (Modules) -> OneResult |
                          {'result', analyse_ok(), analyse_fail()} |
                          {'error', 'not_main_node'} when
                  Modules :: modules(),
                  OneResult :: one_result().

analyse(Analysis) when ?is_analysis(Analysis) ->
    analyse('_', Analysis);
analyse(Level) when ?is_level(Level) ->
    analyse('_', Level);
analyse(Module) ->
    analyse(Module, coverage).

-dialyzer({no_contracts,analyse/2}).
-doc """
analyse(Arg1, Arg2)

Analyzes one or more modules as specified by `Arg1` and `Arg2`.

If `Arg1` is one of the values in [`analysis()`](`t:analysis/0`) and
`Arg2` is one of the values in [`level()`](`t:level/0`), this
call is equivalent to [`analyse('_', Arg1, Arg2)`](`analyse/3`).

If `Arg2` is one of the values in [`analysis()`](`t:analysis/0`),
`Arg1` is assumed to be a module and this call is equivalent to
[`analyse(Arg1, Arg2, function)`](`analyse/3`).

If `Arg2` is one of the values in [`level()`](`t:level/0`), `Arg1` is
assumed to be a module and this call is equivalent to [`analyse(Arg1,
coverage, Arg2)`](`analyse/3`).

> #### Note {: .info }
>
> To analyze a module whose name overlaps with one of the values in
> [`analysis()`](`t:analysis/0`), the module name needs to be in a
> list. For example, to analyze a module named `calls`:
>
> ```
> cover:analyse([calls], function).
> ```
""".
-spec analyse(Analysis, Level) -> {'result', analyse_ok(), analyse_fail()} |
                                  {'error', 'not_main_node'} when
                  Analysis :: analysis(),
                  Level :: level();
             (Modules, Analysis) -> OneResult |
                                    {'result', analyse_ok(), analyse_fail()} |
                                    {'error', 'not_main_node'} when
                  Analysis :: analysis(),
                  Modules :: modules(),
                  OneResult :: one_result();
             (Modules, Level) -> OneResult |
                                 {'result', analyse_ok(), analyse_fail()} |
                                 {'error', 'not_main_node'} when
                  Level :: level(),
                  Modules :: modules(),
                  OneResult :: one_result().

analyse(Analysis, Level) when ?is_analysis(Analysis), ?is_level(Level) ->
    analyse('_', Analysis, Level);
analyse(Module, Analysis) when ?is_analysis(Analysis) ->
    analyse(Module, Analysis, function);
analyse(Module, Level) when ?is_level(Level) ->
    analyse(Module, coverage, Level).

-doc """
Perform analysis of one or more cover-compiled modules, as specified by
`Analysis` and `Level`, by examining the contents of the internal
database.

If `Modules` is an atom (a single module), the return is `OneResult`,
otherwise the return is `{result, Ok, Fail}`.

If `Modules` is atom `'_'`, all modules that have data in the cover data table
are analysed. Note that this includes both cover-compiled modules and imported
modules.

If a given module is not cover-compiled, this is indicated by the error reason
`{not_cover_compiled, Module}`.
""".
-spec analyse(Modules, Analysis, Level) ->
                     OneResult |
                     {'result', analyse_ok(), analyse_fail()} |
                     {'error', 'not_main_node'} when
      Analysis :: analysis(),
      Level :: level(),
      Modules :: modules(),
      OneResult :: one_result().

analyse(Module, Analysis, Level) when ?is_analysis(Analysis),
				      ?is_level(Level) ->
    call({{analyse, Analysis, Level}, Module}).

-doc false.
analyze() -> analyse( ).
-doc false.
analyze(Module) -> analyse(Module).
-doc false.
analyze(Module, Analysis) -> analyse(Module, Analysis).
-doc false.
analyze(Module, Analysis, Level) -> analyse(Module, Analysis, Level).

%% Kept for backwards compatibility:
%% analyse_to_file(Modules, OutFile) ->
%% analyse_to_file(Modules, OutFile, Options) -> {ok,OutFile} | {error,Error}

-doc(#{equiv => analyse_to_file('_', []),
       since => <<"OTP 18.0">>}).
-spec analyse_to_file() -> {'result', analyse_file_ok(), analyse_file_fail()} |
                           {'error', 'not_main_node'}.

analyse_to_file() ->
    analyse_to_file('_').

-type analyse_option() :: 'html'
                        | {'outfile', OutFile :: file:filename()}
                        | {'outdir', OutDir :: file:filename()}.
-type analyse_answer() :: {'ok', OutFile :: file:filename()} |
                          {'error', analyse_rsn()}.
-type analyse_file_ok() :: [OutFile :: file:filename()].
-type analyse_file_fail() :: [analyse_rsn()].
-type analyse_rsn() :: {'not_cover_compiled', Module :: module()} |
                       {'file', File :: file:filename(), Reason :: term()} |
                       {'no_source_code_found', Module :: module()}.

-dialyzer({no_contracts, analyse_to_file/1}).
%% The option list [html] overlaps with module list [html].
-doc """

If `Arg` is a list of [`analyse_option()`](`t:analyse_option/0`)
options, this call is equivalent to [`analyse_to_file('_',
Arg)`](`analyse_to_file/2`).

Otherwise `Arg` is assumed to be a module, and this call is equivalent to
[`analyse_to_file(Arg, [])`](`analyse_to_file/2`).

> #### Note {: .info }
>
> To analyze a module of the name `html` (which overlaps with an option
> in [`analyse_option()`](`t:analyse_option/0`)), it is necessary to
> use `cover:analyse_to_file/2`:
>
> ```
> cover:analyse_to_file([html], []).
> ```

""".
-spec analyse_to_file(Modules) -> Answer |
                                  {'result',
                                   analyse_file_ok(), analyse_file_fail()} |
                                  {'error', 'not_main_node'} when
                          Modules :: modules(),
                          Answer :: analyse_answer();
                     (Options) -> {'result',
                                   analyse_file_ok(), analyse_file_fail()} |
                                  {'error', 'not_main_node'} when
                          Options :: [analyse_option()].

analyse_to_file(Arg) ->
    case is_options(Arg) of
	true ->
	    analyse_to_file('_', Arg);
	false ->
	    analyse_to_file(Arg, [])
    end.

-doc """
Outputs copies of the source code for the given modules annotated with
execution counts for each executable line.

The output file `OutFile` defaults to `Module.COVER.out`, and to `Module.COVER.html`
if option `html` is used.

If `Modules` is an atom (one module), the return will be `Answer`, otherwise the
return will be a list, `{result, Ok, Fail}`.

If `Modules` is '_', all modules that have data in the Cover data table
are analysed. Note that this includes both cover-compiled modules and imported
modules.

If a module is not cover-compiled, this is indicated by the error reason
`{not_cover_compiled, Module}`.

If the source file and/or the output file cannot be opened using `file:open/2`,
the function returns `{error, {file, File, Reason}}`, where `File` is the file
name and `Reason` is the error reason.

If a module was cover compiled from the `.beam` file, that is, using
`compile_beam/1` or
[`compile_beam_directory/0,1` ](`compile_beam_directory/0`), it is assumed that
the source code can be found in one of the following locations:

- the same directory as the `.beam` file
- `../src` relative to the directory with `.beam` file
- the source path in `Module:module_info(compile)`, in which case two paths
  are examined:
  * first the one constructed by joining `../src` and the tail of the compiled path
    below a trailing `src` component
  * the compiled path itself

If no source code is found, this is indicated by the error reason
`{no_source_code_found, Module}`.
""".
-spec analyse_to_file(Modules, Options) ->
                             Answer |
                             {'result',
                              analyse_file_ok(), analyse_file_fail()} |
                             {'error', 'not_main_node'} when
      Modules :: modules(),
      Options :: [analyse_option()],
      Answer :: analyse_answer().

analyse_to_file(Module, OutFile) when is_list(OutFile), is_integer(hd(OutFile)) ->
    %% Kept for backwards compatibility
    analyse_to_file(Module, [{outfile,OutFile}]);
analyse_to_file(Module, Options) when is_list(Options) ->
    call({{analyse_to_file, Options}, Module}).

-doc false.
analyse_to_file(Module, OutFile, Options) when is_list(OutFile) ->
    %% Kept for backwards compatibility
    analyse_to_file(Module,[{outfile,OutFile}|Options]).

-doc false.
analyze_to_file() -> analyse_to_file().
-doc false.
analyze_to_file(Module) -> analyse_to_file(Module).
-doc false.
analyze_to_file(Module, OptOrOut) -> analyse_to_file(Module, OptOrOut).
-doc false.
analyze_to_file(Module, OutFile, Options) -> 
    analyse_to_file(Module, OutFile, Options).

-doc(#{equiv => async_analyse_to_file/3}).
-doc(#{since => <<"OTP R14B02">>}).
-spec async_analyse_to_file(Module) -> pid() when
      Module :: module().

async_analyse_to_file(Module) ->
    do_spawn(?MODULE, analyse_to_file, [Module]).

-dialyzer({no_contracts, async_analyse_to_file/2}).
%% The types file:filename() (string()) and ['html'] has something in
%% common, namely [].
-doc(#{equiv => async_analyse_to_file/3}).
-doc(#{since => <<"OTP R14B02">>}).
-spec async_analyse_to_file(Module, OutFile) -> pid() when
                                Module :: module(),
                                OutFile :: file:filename();
                           (Module, Options) -> pid() when
                                Module :: module(),
                                Options :: [Option],
                                Option :: 'html'.

async_analyse_to_file(Module, OutFileOrOpts) ->
    do_spawn(?MODULE, analyse_to_file, [Module, OutFileOrOpts]).

-doc """
This function works the same way as
[`analyse_to_file/2`](`analyse_to_file/2`) except that it is asynchronous instead
of synchronous.

The spawned process will link with the caller when created. If an
error of type [`analyse_rsn()`](`t:analyse_rsn/0`) occurs while doing
the cover analysis the process will crash with the same error reason
as [`analyse_to_file`](`analyse_to_file/1`) would return.
""".
-doc(#{since => <<"OTP R14B02">>}).
-spec async_analyse_to_file(Module, OutFile, Options) -> pid() when
      Module :: module(),
      OutFile :: file:filename(),
      Options :: [Option],
      Option :: 'html'.

async_analyse_to_file(Module, OutFile, Options) ->
    do_spawn(?MODULE, analyse_to_file, [Module, OutFile, Options]).

is_options([html]) ->
    true; % this is not 100% safe - could be a module named html...
is_options([html|Opts]) ->
    is_options(Opts);
is_options([{Opt,_}|_]) when Opt==outfile; Opt==outdir ->
    true;
is_options(_) ->
    false.

do_spawn(M,F,A) ->
    spawn_link(fun() ->
		  case apply(M,F,A) of
		      {ok, _} ->
			  ok;
		      {error, Reason} ->
			  exit(Reason)
		  end
	  end).

-doc false.
async_analyze_to_file(Module) ->
    async_analyse_to_file(Module).
-doc false.
async_analyze_to_file(Module, OutFileOrOpts) ->
    async_analyse_to_file(Module, OutFileOrOpts).
-doc false.
async_analyze_to_file(Module, OutFile, Options) ->
    async_analyse_to_file(Module, OutFile, Options).

outfilename(undefined, Module, HTML) ->
    outfilename(Module, HTML);
outfilename(OutDir, Module, HTML) ->
    filename:join(OutDir, outfilename(Module, HTML)).

outfilename(Module, true) ->
    atom_to_list(Module)++".COVER.html";
outfilename(Module, false) ->
    atom_to_list(Module)++".COVER.out".

-type export_reason() :: {'not_cover_compiled', Module :: module()} |
                         {'cant_open_file',
                          ExportFile :: file:filename(), FileReason :: term()} |
                         'not_main_node'.

-doc #{equiv => export(File, '_')}.
-spec export(File) -> 'ok' | {'error', Reason} when
      File :: file:filename(),
      Reason :: export_reason().

export(File) ->
    export(File, '_').

-doc """
Exports the current coverage data for `Module` to the file `ExportFile`.

It is recommended to name the `ExportFile` with the extension `.coverdata`.

If `Module` is '_', data for all cover-compiled or earlier imported
modules is exported.

This function is useful if coverage data from different systems is to be merged.

See also `import/1`.
""".
-spec export(File, Module) -> 'ok' | {'error', Reason} when
      File :: file:filename(),
      Module :: module(),
      Reason :: export_reason().

export(File, Module) ->
    call({export,File,Module}).

-doc """
Imports coverage data from the file `ExportFile` created with
[`export/1,2`](`export/2`).

Any analysis performed after this call will include the imported data.

Note that when compiling a module _all existing coverage data is removed_,
including imported data. If a module is already compiled when data is imported,
the imported data is _added_ to the existing coverage data.

Coverage data from several export files can be imported into one system. The
coverage data is then added up when analysing.

Coverage data for a module cannot be imported from the same file twice unless
the module is first reset or compiled. The check is based on the filename, so
you can easily fool the system by renaming your export file.
""".
-spec import(ExportFile) -> 'ok' | {'error', Reason} when
      ExportFile :: file:filename(),
      Reason :: {'cant_open_file', ExportFile, FileReason :: term()} |
                'not_main_node'.

import(File) ->
    call({import,File}).

-doc "Returns a list with all modules that are currently cover-compiled.".
-spec modules() -> [module()] | {'error', 'not_main_node'}.

modules() ->
   call(modules).

-doc "Returns a list of all modules for which there are imported data.".
-spec imported_modules() -> [module()] | {'error', 'not_main_node'}.

imported_modules() ->
   call(imported_modules).

-doc "Returns a list of all imported files.".
-spec imported() -> [file:filename()] |  {'error', 'not_main_node'}.

imported() ->
   call(imported).

-doc """
Returns a list with all nodes that are part of the coverage analysis.

Note that the current node is not included, because it is always part
of the analysis.
""".
-spec which_nodes() -> [node()].

which_nodes() ->
   call(which_nodes).

-doc """
Returns `{file, File}` if the module `Module` is cover-compiled, or `false`
otherwise.

`File` is the `.erl` file used by [`compile_module/1,2`](`compile_module/2`)
or the `.beam` file used by `compile_beam/1`.
""".
-spec is_compiled(Module) -> {'file', File :: file:filename()} |
                             'false' |
                             {'error', 'not_main_node'} when
      Module :: module().

is_compiled(Module) when is_atom(Module) ->
    call({is_compiled, Module}).

-doc """
Resets all coverage data for the cover-compiled module `Module` in the Cover
database on all nodes.

If `Module` is not cover-compiled, the function returns
`{error, {not_cover_compiled, Module}}`.
""".
-spec reset(Module) -> 'ok' |
                       {'error', 'not_main_node'} |
                       {'error', {'not_cover_compiled', Module}} when
      Module :: module().

reset(Module) when is_atom(Module) ->
    call({reset, Module}).

-doc """
Resets all coverage data for all cover-compiled modules in the Cover
database on all nodes.
""".
-spec reset() -> 'ok' | {'error', 'not_main_node'}.

reset() ->
    call(reset).

-doc "Stops the Cover server and unloads all cover-compiled code.".
-spec stop() -> 'ok' | {'error', 'not_main_node'}.

stop() ->
    call(stop).

-doc """
Stops the Cover server and unloads all cover-compiled code on the given nodes.

Data stored in the Cover database on the remote nodes is fetched and stored on
the main node.
""".
-spec stop(Nodes) -> 'ok' | {'error', 'not_main_node'} when
      Nodes :: node() | [node()].

stop(Node) when is_atom(Node) ->
    stop([Node]);
stop(Nodes) ->
    call({stop,remove_myself(Nodes,[])}).

-doc """
Fetches data from the Cover database on the remote nodes and stores it on the main
node.
""".
-doc(#{since => <<"OTP R16B">>}).
-spec flush(Nodes) -> 'ok' | {'error', 'not_main_node'} when
      Nodes :: node() | [node()].

flush(Node) when is_atom(Node) ->
    flush([Node]);
flush(Nodes) ->
    call({flush,remove_myself(Nodes,[])}).

%% Used by test_server only. Not documented.
-doc false.
get_main_node() ->
    call(get_main_node).

call(Request) ->
    Ref = erlang:monitor(process,?SERVER),
    receive {'DOWN', Ref, _Type, _Object, noproc} -> 
	    erlang:demonitor(Ref),
            {ok,_} = start(),
	    call(Request)
    after 0 ->
	    ?SERVER ! {self(),Request},
	    Return = 
		receive 
		    {'DOWN', Ref, _Type, _Object, Info} -> 
			exit(Info);
		    {?SERVER,Reply} -> 
			Reply
		end,
	    erlang:demonitor(Ref, [flush]),
	    Return
    end.

reply(From, Reply) ->
    From ! {?SERVER,Reply},
    ok.

is_from(From) ->
    is_pid(From).

remote_call(Node,Request) ->
    Ref = erlang:monitor(process,{?SERVER,Node}),
    receive {'DOWN', Ref, _Type, _Object, noproc} -> 
	    erlang:demonitor(Ref),
	    {error,node_dead}
    after 0 ->
	    {?SERVER,Node} ! Request,
	    Return = 
		receive 
		    {'DOWN', Ref, _Type, _Object, _Info} -> 
			case Request of
			    {remote,stop} -> ok;
			    _ -> {error,node_dead}
			end;
		    {?SERVER,Reply} -> 
			Reply
		end,
	    erlang:demonitor(Ref, [flush]),
	    Return
    end.
    
remote_reply(Proc,Reply) when is_pid(Proc) ->
    Proc ! {?SERVER,Reply},
    ok;
remote_reply(MainNode,Reply) ->
    {?SERVER,MainNode} ! {?SERVER,Reply},
    ok.

%%%----------------------------------------------------------------------
%%% cover_server on main node
%%%----------------------------------------------------------------------

init_main(Starter) ->
    try register(?SERVER,self()) of
        true ->
            ?COVER_MAPPING_TABLE = ets:new(?COVER_MAPPING_TABLE,
                                           [ordered_set, public, named_table]),
            ?BINARY_TABLE = ets:new(?BINARY_TABLE, [set, public, named_table]),
            ?COLLECTION_TABLE = ets:new(?COLLECTION_TABLE, [set, public,
                                                            named_table]),
            ok = net_kernel:monitor_nodes(true),
            Starter ! {?SERVER,started},
            main_process_loop(#main_state{})
    catch
        error:badarg ->
            %% The server's already registered; either report that it's already
            %% started or try again if it died before we could find its pid.
            case whereis(?SERVER) of
                undefined ->
                    init_main(Starter);
                Pid ->
                    Starter ! {?SERVER, {error, {already_started, Pid}}}
            end
    end.

-doc false.
main_process_loop(State) ->
    receive
        {From, local_only} ->
            case State of
                #main_state{compiled=[],nodes=[]} ->
                    reply(From, ok),
                    main_process_loop(State#main_state{local_only=true});
                #main_state{} ->
                    reply(From, {error,too_late}),
                    main_process_loop(State)
            end;

	{From, {start_nodes,Nodes}} ->
            case State#main_state.local_only of
                false ->
                    {StartedNodes,State1} = do_start_nodes(Nodes, State),
                    reply(From, {ok,StartedNodes}),
                    main_process_loop(State1);
                true ->
                    reply(From, {error,local_only}),
                    main_process_loop(State)
            end;

	{From, {compile, Files, Options}} ->
	    {R,S} = do_compile(Files, Options, State),
	    reply(From,R),
	    %% This module (cover) could have been reloaded. Make
	    %% sure we run the new code.
	    ?MODULE:main_process_loop(S);

	{From, {compile_beams, ModsAndFiles}} ->
	    {R,S} = do_compile_beams(ModsAndFiles,State),
	    reply(From,R),
	    %% This module (cover) could have been reloaded. Make
	    %% sure we run the new code.
	    ?MODULE:main_process_loop(S);

	{From, {export,OutFile,Module}} ->
	    spawn(fun() ->
			  ?SPAWN_DBG(export,{OutFile, Module}),
			  do_export(Module, OutFile, From, State)
		  end),
	    main_process_loop(State);
	
	{From, {import,File}} ->
	    case file:open(File,[read,binary,raw]) of
		{ok,Fd} ->
		    Imported = do_import_to_table(Fd,File,
						  State#main_state.imported),
		    reply(From, ok),
		    ok = file:close(Fd),
		    main_process_loop(State#main_state{imported=Imported});
		{error,Reason} ->
		    reply(From, {error, {cant_open_file,File,Reason}}),
		    main_process_loop(State)
	    end;

	{From, modules} ->
	    %% Get all compiled modules which are still loaded
	    {LoadedModules,Compiled} = 
		get_compiled_still_loaded(State#main_state.nodes,
					  State#main_state.compiled),
	    
	    reply(From, LoadedModules),
	    main_process_loop(State#main_state{compiled=Compiled});

	{From, imported_modules} ->
	    %% Get all modules with imported data
	    ImportedModules = lists:map(fun({Mod,_File,_ImportFile}) -> Mod end,
					State#main_state.imported),
	    reply(From, ImportedModules),
	    main_process_loop(State);

	{From, imported} ->
	    %% List all imported files
	    reply(From, get_all_importfiles(State#main_state.imported,[])),
	    main_process_loop(State);

	{From, which_nodes} ->
	    %% List all imported files
	    reply(From, State#main_state.nodes),
	    main_process_loop(State);

	{From, reset} ->
	    lists:foreach(
	      fun({Module,_File}) -> 
		      do_reset_main_node(Module,State#main_state.nodes)
	      end, 
	      State#main_state.compiled),
	    reply(From, ok),
	    main_process_loop(State#main_state{imported=[]});

	{From, {stop,Nodes}} ->
	    remote_collect('_',Nodes,true),
	    reply(From, ok),
	    Nodes1 = State#main_state.nodes--Nodes,
	    LostNodes1 = State#main_state.lost_nodes--Nodes,
	    main_process_loop(State#main_state{nodes=Nodes1,
					       lost_nodes=LostNodes1});

	{From, {flush,Nodes}} ->
	    remote_collect('_',Nodes,false),
	    reply(From, ok),
	    main_process_loop(State);

	{From, stop} ->
	    lists:foreach(
	      fun(Node) -> 
		      remote_call(Node,{remote,stop})
	      end,
	      State#main_state.nodes),
	    reload_originals(State#main_state.compiled),
            ets:delete(?COVER_MAPPING_TABLE),
            ets:delete(?BINARY_TABLE),
            ets:delete(?COLLECTION_TABLE),
            delete_all_counters(),
            unregister(?SERVER),
	    reply(From, ok);

	{From, {{analyse, Analysis, Level}, '_'}} ->
	    R = analyse_all(Analysis, Level, State),
	    reply(From, R),
	    main_process_loop(State);

	{From, {{analyse, Analysis, Level}, Modules}} when is_list(Modules) ->
	    R = analyse_list(Modules, Analysis, Level, State),
	    reply(From, R),
	    main_process_loop(State);

	{From, {{analyse, Analysis, Level}, Module}} ->
	    S = try 
		    Loaded = is_loaded(Module, State),
		    spawn(fun() ->
				  ?SPAWN_DBG(analyse,{Module,Analysis, Level}),
				  do_parallel_analysis(
				    Module, Analysis, Level, 
				    Loaded, From, State)
			  end),
		    State
		catch throw:Reason ->
			reply(From,{error, {not_cover_compiled,Module}}),
			not_loaded(Module, Reason, State)
		end,
	    main_process_loop(S);

	{From, {{analyse_to_file, Opts},'_'}} ->
	    R = analyse_all_to_file(Opts, State),
	    reply(From,R),
	    main_process_loop(State);

	{From, {{analyse_to_file, Opts},Modules}} when is_list(Modules) ->
	    R = analyse_list_to_file(Modules, Opts, State),
	    reply(From,R),
	    main_process_loop(State);

	{From, {{analyse_to_file, Opts},Module}} ->
	    S = try 
		    Loaded = is_loaded(Module, State),
		    spawn_link(fun() ->
				  ?SPAWN_DBG(analyse_to_file,{Module,Opts}),
				  do_parallel_analysis_to_file(
				    Module, Opts, Loaded, From, State)
			  end),
		    State
		catch throw:Reason ->
			reply(From,{error, {not_cover_compiled,Module}}),
			not_loaded(Module, Reason, State)
		end,
	    main_process_loop(S);

	{From, {is_compiled, Module}} ->
	    S = try is_loaded(Module, State) of
		    {loaded, File} ->
			reply(From,{file, File}),
			State;
		    {imported,_File,_ImportFiles} ->
			reply(From,false),
			State
		catch throw:Reason ->
			reply(From,false),
			not_loaded(Module, Reason, State)
		end,
	    main_process_loop(S);

	{From, {reset, Module}} ->
	    S = try 
		    Loaded = is_loaded(Module,State),
		    R = case Loaded of
			    {loaded, _File} ->
				do_reset_main_node(
				  Module, State#main_state.nodes);
			    {imported, _File, _} ->
				do_reset_collection_table(Module)
			end,
		    Imported = 
			remove_imported(Module,
					State#main_state.imported),
		    reply(From, R),
		    State#main_state{imported=Imported}
		catch throw:Reason ->
			reply(From,{error, {not_cover_compiled,Module}}),
			not_loaded(Module, Reason, State)
		end,
	    main_process_loop(S);		    
	
	{'DOWN', _MRef, process, {?SERVER,Node}, _Info} ->
	    %% A remote cover_server is down, mark as lost
	    {Nodes,Lost} =
		case lists:member(Node,State#main_state.nodes) of
		    true ->
			N = State#main_state.nodes--[Node],
			L = [Node|State#main_state.lost_nodes],
			{N,L};
		    false -> % node stopped
			{State#main_state.nodes,State#main_state.lost_nodes}
		end,
	    main_process_loop(State#main_state{nodes=Nodes,lost_nodes=Lost});

	{nodeup,Node} ->
	    State1 =
		case lists:member(Node,State#main_state.lost_nodes) of
		    true ->
			sync_compiled(Node,State);
		    false ->
			State
	    end,
	    main_process_loop(State1);

	{nodedown,_} ->
	    %% Will be taken care of when 'DOWN' message arrives
	    main_process_loop(State);
	
	{From, get_main_node} ->
	    reply(From, node()),
	    main_process_loop(State);

	get_status ->
	    io:format("~tp~n",[State]),
	    main_process_loop(State)
    end.

%%%----------------------------------------------------------------------
%%% cover_server on remote node
%%%----------------------------------------------------------------------

init_remote(Starter,MainNode) ->
    register(?SERVER,self()),
    ?COVER_MAPPING_TABLE = ets:new(?COVER_MAPPING_TABLE,
                                   [ordered_set, public, named_table]),
    Starter ! {self(),started},
    remote_process_loop(#remote_state{main_node=MainNode}).



-doc false.
remote_process_loop(State) ->
    receive 
	{remote,load_compiled,Compiled} ->
	    Compiled1 = load_compiled(Compiled,State#remote_state.compiled),
	    remote_reply(State#remote_state.main_node, ok),
	    ?MODULE:remote_process_loop(State#remote_state{compiled=Compiled1});

	{remote,unload,UnloadedModules} ->
	    unload(UnloadedModules),
	    Compiled = 
		update_compiled(UnloadedModules, State#remote_state.compiled),
	    remote_reply(State#remote_state.main_node, ok),
	    remote_process_loop(State#remote_state{compiled=Compiled});

	{remote,reset,Module} ->
	    reset_counters(Module),
	    remote_reply(State#remote_state.main_node, ok),
	    remote_process_loop(State);

	{remote,collect,Module,CollectorPid} ->
	    self() ! {remote,collect,Module,CollectorPid, ?SERVER};

	{remote,collect,Modules0,CollectorPid,From} ->
	    Modules = case Modules0 of
			  '_' -> [M || {M,_} <- State#remote_state.compiled];
			  _ -> Modules0
		      end,
            spawn(fun() ->
                          ?SPAWN_DBG(remote_collect, 
                                     {Modules, CollectorPid, From}),
                          do_collect(Modules, CollectorPid, From)
                  end),
	    remote_process_loop(State);

	{remote,stop} ->
	    reload_originals(State#remote_state.compiled),
	    ets:delete(?COVER_MAPPING_TABLE),
            delete_all_counters(),
            unregister(?SERVER),
	    ok; % not replying since 'DOWN' message will be received anyway

	{remote,get_compiled} ->
	    remote_reply(State#remote_state.main_node,
			 State#remote_state.compiled),
	    remote_process_loop(State);

	{From, get_main_node} ->
	    remote_reply(From, State#remote_state.main_node),
	    remote_process_loop(State);

	get_status ->
	    io:format("~tp~n",[State]),
	    remote_process_loop(State);

	M ->
	    io:format("WARNING: remote cover_server received\n~p\n",[M]),
	    case M of
		{From,_} ->
		    case is_from(From) of
			true ->
			    reply(From,{error,not_main_node});
		        false ->
			    ok
		    end;
		_ ->
		    ok
	    end,
	    remote_process_loop(State)
	    
    end.

do_collect(Modules, CollectorPid, From) ->
    _ = pmap(fun(Module) ->
                     send_counters(Module, CollectorPid)
             end, Modules),
    CollectorPid ! done,
    remote_reply(From, ok).

send_chunk(CollectorPid,Chunk) ->
    CollectorPid ! {chunk,Chunk,self()},
    receive continue -> ok end.

get_downs([]) ->
    ok;
get_downs(Mons) ->
    receive
	{'DOWN', Ref, _Type, Pid, _Reason} = Down ->
	    case lists:member({Pid,Ref},Mons) of
		true ->
		    get_downs(lists:delete({Pid,Ref},Mons));
		false ->
		    %% This should be handled somewhere else
		    self() ! Down,
		    get_downs(Mons)
	    end
    end.

reload_originals(Compiled) ->
    _ = pmap(fun do_reload_original/1, [M || {M,_} <- Compiled]),
    ok.

do_reload_original(Module) ->
    case code:which(Module) of
	?TAG ->
	    _ = code:purge(Module),     % remove code marked as 'old'
	    _ = code:delete(Module),    % mark cover compiled code as 'old'
	    %% Note: original beam code must be loaded before the cover
	    %% compiled code is purged, in order to for references to
	    %% 'fun M:F/A' and %% 'fun F/A' funs to be correct (they
	    %% refer to (M:)F/A in the *latest* version  of the module)
            _ = code:load_file(Module), % load original code
	    _ = code:purge(Module);     % remove cover compiled code
	_ ->
	    ignore
    end.

load_compiled([Data|Compiled],Acc) ->
    %% Make sure the #bump{} records and counters are available *before*
    %% compiling and loading the code.
    #remote_data{module=Module,file=File,code=Beam,
                 mapping=InitialMapping} = Data,
    ets:insert(?COVER_MAPPING_TABLE, InitialMapping),
    maybe_create_counters(Module, true),

    Sticky = case code:is_sticky(Module) of
                 true ->
                     code:unstick_mod(Module),
                     true;
                 false ->
                     false
             end,
    NewAcc = case code:load_binary(Module, ?TAG, Beam) of
                 {module,Module} ->
                     add_compiled(Module, File, Acc);
                 _  ->
                     do_clear(Module),
                     Acc
             end,
    case Sticky of
        true -> code:stick_mod(Module);
        false -> ok
    end,
    load_compiled(Compiled,NewAcc);
load_compiled([],Acc) ->
    Acc.

unload([Module|Modules]) ->
    do_clear(Module),
    do_reload_original(Module),
    unload(Modules);
unload([]) ->
    ok.

%%%----------------------------------------------------------------------
%%% Internal functions
%%%----------------------------------------------------------------------

%%%--Handling of remote nodes--------------------------------------------

do_start_nodes(Nodes, State) ->
    ThisNode = node(),
    StartedNodes =
	lists:foldl(
	  fun(Node,Acc) ->
		  case rpc:call(Node,cover,remote_start,[ThisNode]) of
		      {ok,_RPid} ->
			  erlang:monitor(process,{?SERVER,Node}),
			  [Node|Acc];
		      Error ->
			  io:format("Could not start cover on ~w: ~tp\n",
				    [Node,Error]),
			  Acc
		  end
	  end,
	  [],
	  Nodes),

    %% In case some of the compiled modules have been unloaded they
    %% should not be loaded on the new node.
    {_LoadedModules,Compiled} =
	get_compiled_still_loaded(State#main_state.nodes,
				  State#main_state.compiled),
    remote_load_compiled(StartedNodes, Compiled, State),

    State1 =
	State#main_state{nodes = State#main_state.nodes ++ StartedNodes,
			 compiled = Compiled},
    {StartedNodes, State1}.

%% start the cover_server on a remote node
-doc false.
remote_start(MainNode) ->
    case whereis(?SERVER) of
	undefined ->
	    Starter = self(),
	    Pid = spawn(fun() -> 
				?SPAWN_DBG(remote_start,{MainNode}),
				init_remote(Starter,MainNode) 
			end),
	    Ref = erlang:monitor(process,Pid),
	    Return = 
		receive 
		    {Pid,started} -> 
			{ok,Pid};
		    {'DOWN', Ref, _Type, _Object, Info} -> 
			{error,Info}
		end,
	    erlang:demonitor(Ref),
	    Return;
	Pid ->
	    {error,{already_started,Pid}}
    end.

%% If a lost node comes back, ensure that main and remote node has the
%% same cover compiled modules. Note that no action is taken if the
%% same {Mod,File} eksists on both, i.e. code change is not handled!
sync_compiled(Node,State) ->
    #main_state{compiled=Compiled0,nodes=Nodes,lost_nodes=Lost}=State,
    State1 =
	case remote_call(Node,{remote,get_compiled}) of
	    {error,node_dead} ->
		{_,S} = do_start_nodes([Node],State),
		S;
	    {error,_} ->
		State;
	    RemoteCompiled ->
		{_,Compiled} =  get_compiled_still_loaded(Nodes,Compiled0),
		Unload = [UM || {UM,_}=U <- RemoteCompiled,
			       false == lists:member(U,Compiled)],
		remote_unload([Node],Unload),
		Load = [L || L <- Compiled,
			     false == lists:member(L,RemoteCompiled)],
		remote_load_compiled([Node], Load, State),
		State#main_state{compiled=Compiled, nodes=[Node|Nodes]}
	end,
    State1#main_state{lost_nodes=Lost--[Node]}.

%% Load a set of cover compiled modules on remote nodes,
%% We do it ?MAX_MODS modules at a time so that we don't
%% run out of memory on the cover_server node. 
-define(MAX_MODS, 10).
remote_load_compiled(Nodes, Compiled, #main_state{local_only=LocalOnly}) ->
    case LocalOnly of
        true ->
            ok;
        false ->
            remote_load_compiled(Nodes, Compiled, [], 0)
    end.

remote_load_compiled(_Nodes, [], [], _ModNum) ->
    ok;
remote_load_compiled(Nodes, Compiled, Acc, ModNum) 
  when Compiled == []; ModNum == ?MAX_MODS ->
    RemoteLoadData = get_downs_r(Acc),
    lists:foreach(
      fun(Node) -> 
	      remote_call(Node,{remote,load_compiled,RemoteLoadData})
      end,
      Nodes),
    remote_load_compiled(Nodes, Compiled, [], 0);
remote_load_compiled(Nodes, [MF | Rest], Acc, ModNum) ->
    remote_load_compiled(
      Nodes, Rest,
      [spawn_job_r(fun() -> get_data_for_remote_loading(MF) end) | Acc],
      ModNum + 1).

spawn_job_r(Fun) ->
    spawn_monitor(fun() -> exit(Fun()) end).

get_downs_r([]) ->
    [];
get_downs_r(Mons) ->
    receive
	{'DOWN', Ref, _Type, Pid, #remote_data{}=R} ->
	    [R|get_downs_r(lists:delete({Pid,Ref},Mons))];
	{'DOWN', Ref, _Type, Pid, Reason} = Down ->
	    case lists:member({Pid,Ref},Mons) of
		true ->
		    %% Something went really wrong - don't hang!
		    exit(Reason);
		false ->
		    %% This should be handled somewhere else
		    self() ! Down,
		    get_downs_r(Mons)
	    end
    end.


%% Read all data needed for loading a cover compiled module on a remote node
%% Binary is the beam code for the module and InitialTable is the initial
%% data to insert in ?COVER_TABLE.
get_data_for_remote_loading({Module,File}) ->
    [{Module,Code}] = ets:lookup(?BINARY_TABLE, Module),
    %%! The InitialTable list will be long if the module is big - what to do??
    Mapping = counters_mapping_table(Module),

    #remote_data{module=Module,file=File,code=Code,
                 mapping=Mapping,clauses=[]}.

%% Unload modules on remote nodes
remote_unload(Nodes,UnloadedModules) ->
    lists:foreach(
      fun(Node) -> 
	      remote_call(Node,{remote,unload,UnloadedModules})
      end,
      Nodes).    

%% Reset one or all modules on remote nodes
remote_reset(Module,Nodes) ->
    lists:foreach(
      fun(Node) -> 
	      remote_call(Node,{remote,reset,Module})
      end,
      Nodes).        

%% Collect data from remote nodes - used for analyse or stop(Node)
remote_collect(Modules,Nodes,Stop) ->
    _ = pmap(
          fun(Node) -> 
                  ?SPAWN_DBG(remote_collect, 
                             {Modules, Nodes, Stop}),
                  do_collection(Node, Modules, Stop)
          end, Nodes),
    ok.

do_collection(Node, Module, Stop) ->
    CollectorPid = spawn(fun collector_proc/0),
    case remote_call(Node,{remote,collect,Module,CollectorPid, self()}) of
	{error,node_dead} ->
	    CollectorPid ! done,
	    ok;
	ok when Stop ->
	    remote_call(Node,{remote,stop});
	ok ->
	    ok
    end.

%% Process which receives chunks of data from remote nodes - either when
%% analysing or when stopping cover on the remote nodes.
collector_proc() ->
    ?SPAWN_DBG(collector_proc, []),
    receive 
	{chunk,Chunk,From} ->
	    insert_in_collection_table(Chunk),
	    From ! continue,
	    collector_proc();
	done ->
	    ok
    end.

insert_in_collection_table([{Key,Val}|Chunk]) ->
    insert_in_collection_table(Key,Val),
    insert_in_collection_table(Chunk);
insert_in_collection_table([]) ->
    ok.

insert_in_collection_table(Key,Val) ->
    case ets:member(?COLLECTION_TABLE,Key) of
	true ->
	    _ = ets:update_counter(?COLLECTION_TABLE, Key,Val),
            ok;
	false ->
	    %% Make sure that there are no race conditions from ets:member
	    case ets:insert_new(?COLLECTION_TABLE,{Key,Val}) of
		false ->
		    insert_in_collection_table(Key,Val);
		_ ->
		    ok
	    end
    end.


remove_myself([Node|Nodes],Acc) when Node=:=node() ->
    remove_myself(Nodes,Acc);
remove_myself([Node|Nodes],Acc) ->
    remove_myself(Nodes,[Node|Acc]);
remove_myself([],Acc) ->
    Acc.

%%%--Handling of modules state data--------------------------------------

analyse_info(_Module,[]) ->
    ok;
analyse_info(Module,Imported) ->
    imported_info("Analysis",Module,Imported).

export_info(_Module,[]) ->
    ok;
export_info(_Module,_Imported) ->
    %% Do not print that the export includes imported modules
    ok.

export_info([]) ->
    ok;
export_info(_Imported) ->
    %% Do not print that the export includes imported modules
    ok.

get_all_importfiles([{_M,_F,ImportFiles}|Imported],Acc) ->
    NewAcc = do_get_all_importfiles(ImportFiles,Acc),
    get_all_importfiles(Imported,NewAcc);
get_all_importfiles([],Acc) ->
    Acc.

do_get_all_importfiles([ImportFile|ImportFiles],Acc) ->
    case lists:member(ImportFile,Acc) of
	true ->
	    do_get_all_importfiles(ImportFiles,Acc);
	false ->
	    do_get_all_importfiles(ImportFiles,[ImportFile|Acc])
    end;
do_get_all_importfiles([],Acc) ->
    Acc.

imported_info(Text,Module,Imported) ->
    case lists:keysearch(Module,1,Imported) of
	{value,{Module,_File,ImportFiles}} ->
	    io:format("~ts includes data from imported files\n~tp\n",
		      [Text,ImportFiles]);
	false ->
	    ok
    end.
    
    

add_imported(Module, File, ImportFile, Imported) ->
    add_imported(Module, File, filename:absname(ImportFile), Imported, []).

add_imported(M, F1, ImportFile, [{M,_F2,ImportFiles}|Imported], Acc) ->
    case lists:member(ImportFile,ImportFiles) of
	true ->
	    io:fwrite("WARNING: Module ~w already imported from ~tp~n"
		      "Not importing again!~n",[M,ImportFile]),
	    dont_import;
	false ->
	    NewEntry = {M, F1, [ImportFile | ImportFiles]},
	    {ok, lists:reverse([NewEntry | Acc]) ++ Imported}
    end;
add_imported(M, F, ImportFile, [H|Imported], Acc) ->
    add_imported(M, F, ImportFile, Imported, [H|Acc]);
add_imported(M, F, ImportFile, [], Acc) ->
    {ok, lists:reverse([{M, F, [ImportFile]} | Acc])}.
    
%% Removes a module from the list of imported modules and writes a warning
%% This is done when a module is compiled.
remove_imported(Module,Imported) ->
    case lists:keysearch(Module,1,Imported) of
	{value,{Module,_,ImportFiles}} ->
	    io:fwrite("WARNING: Deleting data for module ~w imported from~n"
		      "~tp~n",[Module,ImportFiles]),
	    lists:keydelete(Module,1,Imported);
	false ->
	    Imported
    end.

%% Adds information to the list of compiled modules, preserving time order
%% and without adding duplicate entries.
add_compiled(Module, File1, [{Module,_File2}|Compiled]) ->
    [{Module,File1}|Compiled];
add_compiled(Module, File, [H|Compiled]) ->
    [H|add_compiled(Module, File, Compiled)];
add_compiled(Module, File, []) ->
    [{Module,File}].

are_loaded([Module|Modules], State, Loaded, Imported, Error) ->
    try is_loaded(Module,State) of
	{loaded,File} ->
	    are_loaded(Modules, State, [{Module,File}|Loaded], Imported, Error);
	{imported,File,_} ->
	    are_loaded(Modules, State, Loaded, [{Module,File}|Imported], Error)
    catch throw:_ ->
	    are_loaded(Modules, State, Loaded, Imported,
		       [{not_cover_compiled,Module}|Error])
    end;
are_loaded([], _State, Loaded, Imported, Error) ->
    {Loaded, Imported, Error}.

is_loaded(Module, State) ->
    case get_file(Module, State#main_state.compiled) of
	{ok, File} ->
	    case code:which(Module) of
		?TAG -> {loaded, File};
		_ -> throw(unloaded)
	    end;
	false ->
	    case get_file(Module,State#main_state.imported) of
		{ok,File,ImportFiles} ->
		    {imported, File, ImportFiles};
		false ->
		    throw(not_loaded)
	    end
    end.

get_file(Module, [{Module, File}|_T]) ->
    {ok, File};
get_file(Module, [{Module, File, ImportFiles}|_T]) ->
    {ok, File, ImportFiles};
get_file(Module, [_H|T]) ->
    get_file(Module, T);
get_file(_Module, []) ->
    false.

get_beam_file(Module,?TAG,Compiled) ->
    {value,{Module,File}} = lists:keysearch(Module,1,Compiled),
    case filename:extension(File) of
	".erl" -> {error,no_beam};
	".beam" -> {ok,File}
    end;
get_beam_file(_Module,BeamFile,_Compiled) ->
    {ok,BeamFile}.

get_modules(Compiled) ->
    lists:map(fun({Module, _File}) -> Module end, Compiled).

update_compiled([Module|Modules], [{Module,_File}|Compiled]) ->
    update_compiled(Modules, Compiled);
update_compiled(Modules, [H|Compiled]) ->
    [H|update_compiled(Modules, Compiled)];
update_compiled(_Modules, []) ->
    [].

%% Get all compiled modules which are still loaded, and possibly an
%% updated version of the Compiled list.
get_compiled_still_loaded(Nodes,Compiled0) ->
    %% Find all cover-compiled modules which are still loaded
    CompiledModules = get_modules(Compiled0),
    LoadedModules = lists:filter(fun(Module) ->
					 case code:which(Module) of
					     ?TAG -> true;
					     _ -> false
					 end
				 end,
				 CompiledModules),

    %% If some cover-compiled modules have been unloaded, update the database.
    UnloadedModules = CompiledModules--LoadedModules,
    Compiled = 
	case UnloadedModules of
	    [] ->
		Compiled0;
	    _ ->
		lists:foreach(fun(Module) -> do_clear(Module) end,
			      UnloadedModules),
		remote_unload(Nodes,UnloadedModules),
		update_compiled(UnloadedModules, Compiled0)
	end,
    {LoadedModules,Compiled}.


%%%--Compilation---------------------------------------------------------

do_compile_beams(ModsAndFiles, State) ->
    Result0 = pmap(fun({ok,Module,File}) ->
			  do_compile_beam(Module, File, State);
		     (Error) ->
			  Error
		  end,
		  ModsAndFiles),
    Compiled = [{M,F} || {ok,M,F} <- Result0],
    remote_load_compiled(State#main_state.nodes, Compiled, State),
    fix_state_and_result(Result0,State,[]).

do_compile_beam(Module,BeamFile0,State) ->
    case get_beam_file(Module,BeamFile0,State#main_state.compiled) of
	{ok,BeamFile} ->
            LocalOnly = State#main_state.local_only,
	    UserOptions = get_compile_options(Module,BeamFile),
	    case do_compile_beam1(Module,BeamFile,
                                  UserOptions,LocalOnly) of
		{ok, Module} ->
		    {ok,Module,BeamFile};
		error ->
		    {error, BeamFile};
		{error,Reason} -> % no abstract code or no 'file' attribute
		    {error, {Reason, BeamFile}}
	    end;
	{error,no_beam} ->
	    %% The module has first been compiled from .erl, and now
	    %% someone tries to compile it from .beam
	    {error,{already_cover_compiled,no_beam_found,Module}}
    end.

fix_state_and_result([{ok,Module,BeamFile}|Rest],State,Acc) ->
    Compiled = add_compiled(Module,BeamFile,State#main_state.compiled),
    Imported = remove_imported(Module,State#main_state.imported),
    NewState = State#main_state{compiled=Compiled,imported=Imported},
    fix_state_and_result(Rest,NewState,[{ok,Module}|Acc]);
fix_state_and_result([Error|Rest],State,Acc) ->
    fix_state_and_result(Rest,State,[Error|Acc]);
fix_state_and_result([],State,Acc) ->
    {lists:reverse(Acc),State}.


do_compile(Files, Options, State) ->
    LocalOnly = State#main_state.local_only,
    Result0 = pmap(fun(File) ->
			   do_compile1(File, Options, LocalOnly)
		   end,
		   Files),
    Compiled = [{M,F} || {ok,M,F} <- Result0],
    remote_load_compiled(State#main_state.nodes, Compiled, State),
    fix_state_and_result(Result0,State,[]).

do_compile1(File, Options, LocalOnly) ->
    case do_compile2(File, Options, LocalOnly) of
	{ok, Module} ->
	    {ok,Module,File};
	error ->
	    {error,File}
    end.

%% do_compile2(File, Options) -> {ok,Module} | error
do_compile2(File, UserOptions, LocalOnly) ->
    Options = [debug_info,binary,report_errors,report_warnings] ++ UserOptions,
    case compile:file(File, Options) of
	{ok, Module, Binary} ->
	    do_compile_beam1(Module,Binary,UserOptions,LocalOnly);
	error ->
	    error
    end.

%% Beam is a binary or a .beam file name
do_compile_beam1(Module,Beam,UserOptions,LocalOnly) ->
    %% Clear database
    do_clear(Module),

    %% Extract the abstract format.
    case get_abstract_code(Module, Beam) of
	{error,_}=Error ->
            Error;
	{ok,{raw_abstract_v1,Code}} ->
            Forms0 = epp:interpret_file_attribute(Code),
	    case find_main_filename(Forms0) of
		{ok,MainFile} ->
		    do_compile_beam2(Module,Beam,UserOptions,
                                     Forms0,MainFile,LocalOnly);
		Error ->
		    Error
	    end;
	{ok,{_VSN,_Code}} ->
	    %% Wrong version of abstract code. Just report that there
	    %% is no abstract code.
	    {error,no_abstract_code}
    end.

get_abstract_code(Module, Beam) ->
    case beam_lib:chunks(Beam, [abstract_code]) of
	{ok, {Module, [{abstract_code, AbstractCode}]}} ->
            case AbstractCode of
                no_abstract_code=E -> {error, E};
                _ -> {ok,AbstractCode}
            end;
	{error,beam_lib,{key_missing_or_invalid,_,_}} ->
	    {error,encrypted_abstract_code};
	{error,beam_lib,{missing_backend,_,Backend}} ->
	    {error,{missing_backend,Backend}}
    end.

do_compile_beam2(Module,Beam,UserOptions,Forms0,MainFile,LocalOnly) ->
    init_counter_mapping(Module),

    %% Instrument the abstract code by inserting
    %% calls to update the counters.
    Forms = transform(Forms0, Module, MainFile, LocalOnly),

    %% Create counters.
    maybe_create_counters(Module, not LocalOnly),

    %% We need to recover the source from the compilation
    %% info otherwise the newly compiled module will have
    %% source pointing to the current directory
    SourceInfo = get_source_info(Module, Beam),

    %% Compile and load the result.
    %% It's necessary to check the result of loading since it may
    %% fail, for example if Module resides in a sticky directory.
    Options0 = SourceInfo ++ UserOptions,
    Options = [report_errors,force_line_counters|Options0],

    {ok, Module, Binary} = compile:forms(Forms, Options),

    case code:load_binary(Module, ?TAG, Binary) of
	{module, Module} ->
	    %% Store binary code so it can be loaded on remote nodes.
	    ets:insert(?BINARY_TABLE, {Module, Binary}),
	    {ok, Module};
	_Error ->
	    do_clear(Module),
	    error
    end.

get_source_info(Module, Beam) ->
    Compile = get_compile_info(Module, Beam),
    case lists:keyfind(source, 1, Compile) of
        { source, _ } = Tuple -> [Tuple];
        false -> []
    end.

get_compile_options(Module, Beam) ->
    Compile = get_compile_info(Module, Beam),
    case lists:keyfind(options, 1, Compile) of
        {options, Options } -> filter_options(Options);
        false -> []
    end.

get_compile_info(Module, Beam) ->
    case beam_lib:chunks(Beam, [compile_info]) of
	{ok, {Module, [{compile_info, Compile}]}} ->
		Compile;
	_ ->
		[]
    end.

transform(Code, Module, _MainFile, LocalOnly) ->
    {ok,MungedForms0} = sys_coverage:cover_transform(Code, fun counter_index/5),
    patch_code(Module, MungedForms0, LocalOnly).

%% Helpfunction which returns the first found file-attribute, which can
%% be interpreted as the name of the main erlang source file.
find_main_filename([{attribute,_,file,{MainFile,_}}|_]) ->
    {ok,MainFile};
find_main_filename([_|Rest]) ->
    find_main_filename(Rest);
find_main_filename([]) ->
    {error, no_file_attribute}.

%%%--Counters------------------------------------------------------------

init_counter_mapping(Mod) ->
    true = ets:insert_new(?COVER_MAPPING_TABLE, {Mod,0}),
    ok.

counter_index(Mod, F, A, C, Line) ->
    Key = #bump{module=Mod,function=F,arity=A,
                clause=C,line=Line},
    case ets:lookup(?COVER_MAPPING_TABLE, Key) of
        [] ->
            Index = ets:update_counter(?COVER_MAPPING_TABLE,
                                       Mod, {2,1}),
            true = ets:insert(?COVER_MAPPING_TABLE, {Key,Index}),
            Index;
        [{Key,Index}] ->
            Index
    end.

%% Create the counter array and store as a persistent term.
maybe_create_counters(Mod, true) ->
    case has_native_coverage() of
        false ->
            Cref = create_counters(Mod),
            Key = {?MODULE,Mod},
            persistent_term:put(Key, Cref),
            ok;
        true ->
            ok
    end;
maybe_create_counters(_Mod, false) ->
    ok.

create_counters(Mod) ->
    Size0 = ets:lookup_element(?COVER_MAPPING_TABLE, Mod, 2),
    Size = max(1, Size0),                       %Size must not be 0.
    Cref = counters:new(Size, [write_concurrency]),
    ets:insert(?COVER_MAPPING_TABLE, {{counters,Mod},Cref}),
    Cref.

patch_code(Mod, Forms, Local) ->
    case has_native_coverage() of
        true ->
            _ = catch code:reset_coverage(Mod),
            Forms;
        false when Local =:= false ->
            A = erl_anno:new(0),
            AbstrKey = {tuple,A,[{atom,A,?MODULE},{atom,A,Mod}]},
            patch_code1(Forms, {distributed,AbstrKey});
        false when Local =:= true ->
            Cref = create_counters(Mod),
            AbstrCref = cid_to_abstract(Cref),
            patch_code1(Forms, {local_only,AbstrCref})
    end.

%% Go through the abstract code and replace 'executable_line' forms
%% with the actual code to increment the counters.
patch_code1({executable_line,_Anno,Index}, {distributed,AbstrKey}) ->
    %% Replace with counters:add(persistent_term:get(Key), Index, 1).
    %% This code will work on any node.
    A = element(2, AbstrKey),
    GetCref = {call,A,{remote,A,{atom,A,persistent_term},{atom,A,get}},
               [AbstrKey]},
    {call,A,{remote,A,{atom,A,counters},{atom,A,add}},
     [GetCref,{integer,A,Index},{integer,A,1}]};
patch_code1({executable_line,_Anno,Index}, {local_only,AbstrCref}) ->
    %% Replace with counters:add(Cref, Index, 1). This code
    %% will only work on the local node.
    A = element(2, AbstrCref),
    {call,A,{remote,A,{atom,A,counters},{atom,A,add}},
     [AbstrCref,{integer,A,Index},{integer,A,1}]};
patch_code1({clauses,Cs}, Key) ->
    {clauses,[patch_code1(El, Key) || El <- Cs]};
patch_code1({attribute, _, _, _} = Attribute, _Key) ->
    Attribute;
patch_code1([_|_]=List, Key) ->
    [patch_code1(El, Key) || El <- List];
patch_code1(Tuple, Key) when tuple_size(Tuple) >= 3 ->
    Acc = [element(2, Tuple),element(1, Tuple)],
    patch_code_tuple(3, tuple_size(Tuple), Tuple, Key, Acc);
patch_code1(Other, _Key) ->
    Other.

patch_code_tuple(I, Size, Tuple, Key, Acc) when I =< Size ->
    El = patch_code1(element(I, Tuple), Key),
    patch_code_tuple(I + 1, Size, Tuple, Key, [El|Acc]);
patch_code_tuple(_I, _Size, _Tuple, _Key, Acc) ->
    list_to_tuple(lists:reverse(Acc)).

%% Don't try this at home! Assumes knowledge of the internal
%% representation of a counter ref.
cid_to_abstract(Cref0) ->
    A = erl_anno:new(0),
    %% Disable dialyzer warning for breaking opacity.
    Cref = binary_to_term(term_to_binary(Cref0)),
    {write_concurrency,Ref} = Cref,
    {tuple,A,[{atom,A,write_concurrency},{integer,A,Ref}]}.

%% Called on the remote node. Collect and send counters to
%% the main node. Also zero the counters.
send_counters(Mod, CollectorPid) ->
    Process = fun(Chunk) -> send_chunk(CollectorPid, Chunk) end,
    move_counters(Mod, Process).

%% Called on the main node. Collect the counters and consolidate
%% them into the collection table. Also zero the counters.
move_counters(Mod) ->
    Process = fun insert_in_collection_table/1,
    move_counters(Mod, Process).

move_counters(Mod, Process) ->
    Move = case has_native_coverage() of
               true ->
                   native_move(Mod);
               false ->
                   standard_move(Mod)
           end,
    Pattern = {#bump{module=Mod,_='_'},'_'},
    Matches = ets:match_object(?COVER_MAPPING_TABLE, Pattern, ?CHUNK_SIZE),
    move_counters1(Matches, Move, Process).

move_counters1({Mappings,Continuation}, Move, Process) ->
    Moved = [Move(Item) || Item <- Mappings],
    Process(Moved),
    move_counters1(ets:match_object(Continuation), Move, Process);
move_counters1('$end_of_table', _Move, _Process) ->
    ok.

counters_mapping_table(Mod) ->
    Mapping = counters_mapping(Mod),
    case has_native_coverage() of
        false ->
            Cref = get_counters_ref(Mod),
            #{size:=Size} = counters:info(Cref),
            [{Mod,Size}|Mapping];
        true ->
            Mapping
    end.

get_counters_ref(Mod) ->
    ets:lookup_element(?COVER_MAPPING_TABLE, {counters,Mod}, 2).

counters_mapping(Mod) ->
    Pattern = {#bump{module=Mod,_='_'},'_'},
    ets:match_object(?COVER_MAPPING_TABLE, Pattern).

clear_counters(Mod) ->
    _ = persistent_term:erase({?MODULE,Mod}),
    ets:delete(?COVER_MAPPING_TABLE, Mod),
    Pattern = {#bump{module=Mod,_='_'},'_'},
    _ = ets:match_delete(?COVER_MAPPING_TABLE, Pattern),
    ok.

standard_move(Mod) ->
    Cref = get_counters_ref(Mod),
    fun({Key,Index}) ->
            Count = counters:get(Cref, Index),
            ok = counters:sub(Cref, Index, Count),
            {Key,Count}
    end.

native_move(Mod) ->
    Coverage = maps:from_list(code:get_coverage(cover_id_line, Mod)),
    _ = code:reset_coverage(Mod),
    fun({#bump{}=Key,Index}) ->
            case Coverage of
                #{Index := false} ->
                    {Key,0};
                #{Index := true} ->
                    {Key,1};
                #{Index := N} when is_integer(N), N >= 0 ->
                    {Key,N};
                #{} ->
                    {Key,0}
            end
    end.

%% Reset counters (set counters to 0).
reset_counters(Mod) ->
    case has_native_coverage() of
        true ->
            _ = catch code:reset_coverage(Mod),
            ok;
        false ->
            Pattern = {#bump{module=Mod,_='_'},'$1'},
            MatchSpec = [{Pattern,[],['$1']}],
            Matches = ets:select(?COVER_MAPPING_TABLE,
                                 MatchSpec, ?CHUNK_SIZE),
            Cref = get_counters_ref(Mod),
            reset_counters1(Matches, Cref)
    end.

reset_counters1({Indices,Continuation}, Cref) ->
    _ = [counters:put(Cref, N, 0) || N <- Indices],
    reset_counters1(ets:select(Continuation), Cref);
reset_counters1('$end_of_table', _Cref) ->
    ok.

delete_all_counters() ->
    _ = [persistent_term:erase(Key) || {?MODULE,_}=Key <- persistent_term:get()],
    ok.

%%%--Analysis------------------------------------------------------------

%% Collect data for all modules
collect(Nodes) ->
    Modules = [Module || {Module,_} <- ets:tab2list(?BINARY_TABLE)],
    collect_modules(Modules, Nodes).

%% Collect data for a list of modules
collect(Modules0, Nodes) ->
    Modules = [Module || Module <- Modules0, ets:member(?BINARY_TABLE, Module)],
    collect_modules(Modules, Nodes).

collect_modules(Modules, Nodes) ->
    Mon1 = spawn_monitor(fun() -> pmap(fun move_modules/1, Modules) end),
    Mon2 = spawn_monitor(fun() -> remote_collect('_', Nodes, false) end),
    get_downs([Mon1,Mon2]).

%% Collect data for one module
collect_module(Module, #main_state{nodes=Nodes}) ->
    move_modules(Module),
    remote_collect([Module], Nodes, false).

%% When analysing, the data from the local ?COVER_TABLE is moved to the
%% ?COLLECTION_TABLE. Resetting data in ?COVER_TABLE
move_modules(Module) when is_atom(Module) ->
    move_counters(Module).

%% Given a .beam file, find the .erl file. Look first in same directory as
%% the .beam file, then in ../src, then in compile info.
find_source(Module, File0) ->
    try
        Root = filename:rootname(File0, ".beam"),
        Root == File0 andalso throw(File0),  %% not .beam
        %% Look for .erl in pwd.
        File = Root ++ ".erl",
        throw_file(File),
        %% Not in pwd: look in ../src.
        BeamDir = filename:dirname(File),
        Base = filename:basename(File),
        throw_file(filename:join([BeamDir, "..", "src", Base])),
        %% Not in ../src: look for source path in compile info, but
        %% first look relative the beam directory.
        Info =
            try lists:keyfind(source, 1, Module:module_info(compile))
            catch error:undef ->
                    %% The module might have been imported
                    %% and the beam not available
                    throw({beam, File0})
            end,
        false == Info andalso throw({beam, File0}),  %% stripped
        {source, SrcFile} = Info,
        throw_file(splice(BeamDir, SrcFile)),  %% below ../src
        throw_file(SrcFile),                   %% or absolute
        %% No success means that source is either not under ../src or
        %% its relative path differs from that of compile info. (For
        %% example, compiled under src/x but installed under src/y.)
        %% An option to specify an arbitrary source path explicitly is
        %% probably a better solution than either more heuristics or a
        %% potentially slow filesystem search.
        {beam, File0}
    catch
        Path -> Path
    end.

throw_file(Path) ->
    false /= Path andalso filelib:is_file(Path) andalso throw(Path).

%% Splice the tail of a source path, starting from the last "src"
%% component, onto the parent of a beam directory, or return false if
%% no "src" component is found.
%%
%% Eg. splice("/path/to/app-1.0/ebin", "/compiled/path/to/app/src/x/y.erl")
%%        --> "/path/to/app-1.0/ebin/../src/x/y.erl"
%%
%% This handles the case of source in subdirectories of ../src with
%% beams that have moved since compilation.
%%
splice(BeamDir, SrcFile) ->
    case lists:splitwith(fun(C) -> C /= "src" end, revsplit(SrcFile)) of
        {T, [_|_]} ->  %% found src component
            filename:join([BeamDir, "..", "src" | lists:reverse(T)]);
        {_, []} ->     %% or not
            false
    end.

revsplit(Path) ->
    lists:reverse(filename:split(Path)).

analyse_list(Modules, Analysis, Level, State) ->
    {LoadedMF, ImportedMF, Error} = are_loaded(Modules, State, [], [], []),
    Loaded = [M || {M,_} <- LoadedMF],
    Imported = [M || {M,_} <- ImportedMF],
    collect(Loaded, State#main_state.nodes),
    All = Loaded ++ Imported,
    Fun = fun(Module) ->
		  do_analyse(Module, Analysis, Level)
	  end,
    {result, lists:flatten(pmap(Fun, All)), Error}.

analyse_all(Analysis, Level, State) ->
    collect(State#main_state.nodes),
    All = ets:tab2list(?BINARY_TABLE),
    Fun = fun({Module,_}) ->
		  do_analyse(Module, Analysis, Level)
	  end,
    {result, lists:flatten(pmap(Fun, All)), []}.

do_parallel_analysis(Module, Analysis, Level, Loaded, From, State) ->
    analyse_info(Module,State#main_state.imported),
    _ = case Loaded of
	    {loaded, _File} ->
		collect_module(Module, State);
	    _ ->
                ok
	end,
    R = do_analyse(Module, Analysis, Level),
    reply(From, {ok,R}).

%% do_analyse(Module, Analysis, Level, Clauses)-> {ok,Answer} | {error,Error}
%%   Clauses = [{Module,Function,Arity,Clause,Lines}]
do_analyse(Module, Analysis, line) ->
    Pattern = {#bump{module=Module},'_'},
    Bumps = ets:match_object(?COLLECTION_TABLE, Pattern),
    Fun = case Analysis of
	      coverage ->
		  fun({#bump{line=L}, 0}) ->
			  {{Module,L}, {0,1}};
		     ({#bump{line=L}, _N}) ->
			  {{Module,L}, {1,0}}
		  end;
	      calls ->
		  fun({#bump{line=L}, N}) ->
			  {{Module,L}, N}
		  end
	  end,
    L = lists:keysort(1, lists:map(Fun, Bumps)),
    merge_dup_lines(L);
do_analyse(Module, Analysis, clause) ->
    Pattern = {#bump{module=Module},'_'},
    Bumps = lists:keysort(1,ets:match_object(?COLLECTION_TABLE, Pattern)),
    analyse_clause(Analysis,Bumps);
do_analyse(Module, Analysis, function) ->
    ClauseResult = do_analyse(Module, Analysis, clause),
    merge_clauses(ClauseResult, merge_fun(Analysis));
do_analyse(Module, Analysis, module) ->
    FunctionResult = do_analyse(Module, Analysis, function),
    Result = merge_functions(FunctionResult, merge_fun(Analysis)),
    {Module,Result}.

analyse_clause(_,[]) ->
    [];
analyse_clause(coverage,
	       [{#bump{module=M,function=F,arity=A,clause=C},_}|_]=Bumps) ->
    analyse_clause_cov(Bumps,{M,F,A,C},0,0,[]);
analyse_clause(calls,Bumps) ->
    analyse_clause_calls(Bumps,{x,x,x,x},[]).

analyse_clause_cov([{#bump{module=M,function=F,arity=A,clause=C},N}|Bumps],
		   {M,F,A,C}=Clause,Ls,NotCov,Acc) ->
    analyse_clause_cov(Bumps,Clause,Ls+1,if N==0->NotCov+1; true->NotCov end,Acc);
analyse_clause_cov([{#bump{module=M1,function=F1,arity=A1,clause=C1},_}|_]=Bumps,
		    Clause,Ls,NotCov,Acc) ->
    analyse_clause_cov(Bumps,{M1,F1,A1,C1},0,0,[{Clause,{Ls-NotCov,NotCov}}|Acc]);
analyse_clause_cov([],Clause,Ls,NotCov,Acc) ->
    lists:reverse(Acc,[{Clause,{Ls-NotCov,NotCov}}]).

analyse_clause_calls([{#bump{module=M,function=F,arity=A,clause=C},_}|Bumps],
		     {M,F,A,C}=Clause,Acc) ->
    analyse_clause_calls(Bumps,Clause,Acc);
analyse_clause_calls([{#bump{module=M1,function=F1,arity=A1,clause=C1},N}|Bumps],
		     _Clause,Acc) ->
    analyse_clause_calls(Bumps,{M1,F1,A1,C1},[{{M1,F1,A1,C1},N}|Acc]);
analyse_clause_calls([],_Clause,Acc) ->
    lists:reverse(Acc).

merge_fun(coverage) ->
    fun({Cov1,NotCov1}, {Cov2,NotCov2}) ->
	    {Cov1+Cov2, NotCov1+NotCov2}
    end;
merge_fun(calls) ->
    fun(Calls1, Calls2) ->
	    Calls1+Calls2
    end.

merge_clauses(Clauses, MFun) -> merge_clauses(Clauses, MFun, []).
merge_clauses([{{M,F,A,_C1},R1},{{M,F,A,C2},R2}|Clauses], MFun, Result) ->
    merge_clauses([{{M,F,A,C2},MFun(R1,R2)}|Clauses], MFun, Result);
merge_clauses([{{M,F,A,_C},R}|Clauses], MFun, Result) ->
    merge_clauses(Clauses, MFun, [{{M,F,A},R}|Result]);
merge_clauses([], _Fun, Result) ->
    lists:reverse(Result).

merge_functions([{_MFA,R}|Functions], MFun) ->
    merge_functions(Functions, MFun, R);
merge_functions([],_MFun) ->         % There are no clauses.
    {0,0}.                           % No function can be covered or notcov.

merge_functions([{_MFA,R}|Functions], MFun, Result) ->
    merge_functions(Functions, MFun, MFun(Result, R));
merge_functions([], _MFun, Result) ->
    Result.

analyse_list_to_file(Modules, Opts, State) ->
    {LoadedMF, ImportedMF, Error} = are_loaded(Modules, State, [], [], []),
    collect([M || {M,_} <- LoadedMF], State#main_state.nodes),
    OutDir = proplists:get_value(outdir,Opts),
    HTML = lists:member(html,Opts),
    Fun = fun({Module,File}) ->
		  OutFile = outfilename(OutDir,Module,HTML),
		  do_analyse_to_file(Module,File,OutFile,HTML,State)
	  end,
    {Ok,Error1} = split_ok_error(pmap(Fun, LoadedMF++ImportedMF),[],[]),
    {result,Ok,Error ++ Error1}.

analyse_all_to_file(Opts, State) ->
    collect(State#main_state.nodes),
    AllModules = get_all_modules(State),
    OutDir = proplists:get_value(outdir,Opts),
    HTML = lists:member(html,Opts),
    Fun = fun({Module,File}) ->
		  OutFile = outfilename(OutDir,Module,HTML),
		  do_analyse_to_file(Module,File,OutFile,HTML,State)
	  end,
    {Ok,Error} = split_ok_error(pmap(Fun, AllModules),[],[]),
    {result,Ok,Error}.

get_all_modules(State) ->
    get_all_modules(State#main_state.compiled ++ State#main_state.imported,[]).
get_all_modules([{Module,File}|Rest],Acc) ->
    get_all_modules(Rest,[{Module,File}|Acc]);
get_all_modules([{Module,File,_}|Rest],Acc) ->
    case lists:keymember(Module,1,Acc) of
	true -> get_all_modules(Rest,Acc);
	false -> get_all_modules(Rest,[{Module,File}|Acc])
    end;
get_all_modules([],Acc) ->
    Acc.

split_ok_error([{ok,R}|Result],Ok,Error) ->
    split_ok_error(Result,[R|Ok],Error);
split_ok_error([{error,R}|Result],Ok,Error) ->
    split_ok_error(Result,Ok,[R|Error]);
split_ok_error([],Ok,Error) ->
    {Ok,Error}.

do_parallel_analysis_to_file(Module, Opts, Loaded, From, State) ->
    File = case Loaded of
	       {loaded, File0} ->
		   collect_module(Module, State),
		   File0;
	       {imported, File0, _} ->
		   File0
	   end,
    HTML = lists:member(html,Opts),
    OutFile =
	case proplists:get_value(outfile,Opts) of
	    undefined ->
		outfilename(proplists:get_value(outdir,Opts),Module,HTML);
	    F ->
		F
	end,
    reply(From, do_analyse_to_file(Module,File,OutFile,HTML,State)).

do_analyse_to_file(Module,File,OutFile,HTML,State) ->
    case find_source(Module, File) of
	{beam,_BeamFile} ->
	    {error,{no_source_code_found,Module}};
	ErlFile ->
	    analyse_info(Module,State#main_state.imported),
	    do_analyse_to_file1(Module,OutFile,ErlFile,HTML)
    end.

%% do_analyse_to_file1(Module,OutFile,ErlFile) -> {ok,OutFile} | {error,Error}
%%   Module = atom()
%%   OutFile = ErlFile = string()
do_analyse_to_file1(Module, OutFile, ErlFile, HTML) ->
    case file:open(ErlFile, [read,raw,read_ahead]) of
	{ok, InFd} ->
	    case file:open(OutFile, [write,raw,delayed_write]) of
		{ok, OutFd} ->
                    Enc = encoding(ErlFile),
		    if HTML ->
                            Header = create_header(OutFile, Enc),
                            H1Bin = unicode:characters_to_binary(Header,Enc,Enc),
                            ok = file:write(OutFd,H1Bin);
		       true -> ok
		    end,
		    
		    %% Write some initial information to the output file
		    {{Y,Mo,D},{H,Mi,S}} = calendar:local_time(),
                   Timestamp =
                       io_lib:format("~p-~s-~s at ~s:~s:~s",
                                     [Y,
                                      string:pad(integer_to_list(Mo), 2, leading, $0),
                                      string:pad(integer_to_list(D),  2, leading, $0),
                                      string:pad(integer_to_list(H),  2, leading, $0),
                                      string:pad(integer_to_list(Mi), 2, leading, $0),
                                      string:pad(integer_to_list(S),  2, leading, $0)]),

                   OutFileInfo =
                       if HTML ->
                            create_footer(ErlFile, Timestamp);
                          true ->
                            ["File generated from ",ErlFile," by COVER ",
                             Timestamp, "\n\n",
                             "**************************************"
                             "**************************************"
                             "\n\n"]
                          end,

                   H2Bin = unicode:characters_to_binary(OutFileInfo,Enc,Enc),
                   ok = file:write(OutFd, H2Bin),

		    Pattern = {#bump{module=Module,line='$1',_='_'},'$2'},
		    MS = [{Pattern,[{is_integer,'$1'},{'>','$1',0}],[{{'$1','$2'}}]}],
                    CovLines0 =
                        lists:keysort(1, ets:select(?COLLECTION_TABLE, MS)),
                    CovLines = merge_dup_lines(CovLines0),
		    print_lines(Module, CovLines, InFd, OutFd, 1, HTML),
		    
		    if HTML ->
                           ok = file:write(OutFd, close_html());
		       true -> ok
		    end,

		    ok = file:close(OutFd),
		    ok = file:close(InFd),

		    {ok, OutFile};

		{error, Reason} ->
		    {error, {file, OutFile, Reason}}
	    end;

	{error, Reason} ->
	    {error, {file, ErlFile, Reason}}
    end.

merge_dup_lines(CovLines) ->
    merge_dup_lines(CovLines, []).
merge_dup_lines([{L, {N1, _N2}}|T], [{L, {NAcc1, _NAcc2}}|TAcc]) ->
    case N1 + NAcc1 of
        0 ->
            merge_dup_lines(T, [{L, {0, 1}}|TAcc]);
        _ ->
            merge_dup_lines(T, [{L, {1, 0}}|TAcc])
    end;
merge_dup_lines([{L, N}|T], [{L, NAcc}|TAcc]) ->
    merge_dup_lines(T, [{L, NAcc + N}|TAcc]);
merge_dup_lines([{L, N}|T], Acc) ->
    merge_dup_lines(T, [{L, N}|Acc]);
merge_dup_lines([], Acc) ->
    lists:reverse(Acc).

print_lines(Module, CovLines, InFd, OutFd, L, HTML) ->
    case file:read_line(InFd) of
	eof ->
	    ignore;
	{ok,RawLine} ->
	    Line = escape_lt_and_gt(RawLine,HTML),
	    case CovLines of
	       [{L,N}|CovLines1] ->
                    if N=:=0, HTML=:=true ->
                           MissedLine = table_row("miss", Line, L, N),
                           ok = file:write(OutFd, MissedLine);
                       HTML=:=true ->
                           HitLine = table_row("hit", Line, L, N),
                           ok = file:write(OutFd, HitLine);
                       N < 1000000 ->
                           Str = string:pad(integer_to_list(N), 6, leading, $\s),
                           ok = file:write(OutFd, [Str,fill1(),Line]);
                       N < 10000000 ->
                           Str = integer_to_list(N),
                           ok = file:write(OutFd, [Str,fill2(),Line]);
                       true ->
                           Str = integer_to_list(N),
                           ok = file:write(OutFd, [Str,fill3(),Line])
                    end,
		    print_lines(Module, CovLines1, InFd, OutFd, L+1, HTML);
		_ ->                            %Including comment lines
        NonCoveredContent =
                    if HTML -> table_row(Line, L);
                    true -> [tab(),Line]
                    end,
		    ok = file:write(OutFd, NonCoveredContent),
		    print_lines(Module, CovLines, InFd, OutFd, L+1, HTML)
	    end
    end.

tab() ->  "        |  ".
fill1() ->      "..|  ".
fill2() ->       ".|  ".
fill3() ->        "|  ".

%% HTML sections
create_header(OutFile, Enc) ->
    ["<!doctype html>\n"
    "<html>\n"
    "<head>\n"
    "<meta charset=\"",html_encoding(Enc),"\">\n"
    "<title>",OutFile,"</title>\n"
    "<style>"] ++
    read_stylesheet() ++
    ["</style>\n",
    "</head>\n"
    "<body>\n"
    "<h1><code>",OutFile,"</code></h1>\n"].

create_footer(ErlFile, Timestamp) ->
    ["<footer><p>File generated from <code>",ErlFile,
    "</code> by <a href=\"http://erlang.org/doc/man/cover.html\">cover</a> at ",
    Timestamp,"</p></footer>\n<table>\n<tbody>\n"].

close_html() ->
    ["</tbody>\n",
     "<thead>\n",
     "<tr>\n",
     "<th>Line</th>\n",
     "<th>Hits</th>\n",
     "<th>Source</th>\n",
     "</tr>\n",
     "</thead>\n",
     "</table>\n",
     "</body>\n"
     "</html>\n"].

table_row(CssClass, Line, L, N) ->
    ["<tr class=\"",CssClass,"\">\n", table_data(Line, L, N)].
table_row(Line, L) ->
    ["<tr>\n", table_data(Line, L, "")].

table_data(Line, L, N) ->
   LineNoNL = Line -- "\n",
   ["<td class=\"line\" id=\"L",integer_to_list(L),"\">",
    "<a href=\"#L",integer_to_list(L),"\">",
    integer_to_list(L),
    "</a></td>\n",
   "<td class=\"hits\">",maybe_integer_to_list(N),"</td>\n",
   "<td class=\"source\"><code>",LineNoNL,"</code></td>\n</tr>\n"].

maybe_integer_to_list(0) -> "<pre style=\"display: inline;\">:-(</pre>";
maybe_integer_to_list(N) when is_integer(N) -> integer_to_list(N);
maybe_integer_to_list(_) -> "".

read_stylesheet() ->
    PrivDir = code:priv_dir(?TOOLS_APP),
    {ok, Css} = file:read_file(filename:join(PrivDir, ?STYLESHEET)),
    [Css].

%%%--Export--------------------------------------------------------------
do_export(Module, OutFile, From, State) ->
    case file:open(OutFile,[write,binary,raw,delayed_write]) of
	{ok,Fd} ->
	    Reply = 
		case Module of
		    '_' ->
			export_info(State#main_state.imported),
			collect(State#main_state.nodes),
			do_export_table(State#main_state.compiled,
					State#main_state.imported,
					Fd);
		    _ ->
			export_info(Module,State#main_state.imported),
			try is_loaded(Module, State) of
			    {loaded, File} ->
				collect_module(Module, State),
				do_export_table([{Module,File}],[],Fd);
			    {imported, File, ImportFiles} ->
				%% don't know if I should allow this - 
				%% export a module which is only imported
				Imported = [{Module,File,ImportFiles}],
				do_export_table([],Imported,Fd)
			catch throw:_ ->
				{error,{not_cover_compiled,Module}}
			end
		end,
	    ok = file:close(Fd),
	    reply(From, Reply);
	{error,Reason} ->
	    reply(From, {error, {cant_open_file,OutFile,Reason}})

    end.

do_export_table(Compiled, Imported, Fd) ->
    ModList = merge(Imported,Compiled),
    write_module_data(ModList,Fd).

merge([{Module,File,_ImportFiles}|Imported],ModuleList) ->
    case lists:keymember(Module,1,ModuleList) of
	true ->
	    merge(Imported,ModuleList);
	false ->
	    merge(Imported,[{Module,File}|ModuleList])
    end;
merge([],ModuleList) ->
    ModuleList.

write_module_data([{Module,File}|ModList], Fd) ->
    write({file,Module,File}, Fd),
    ModuleData = ets:match_object(?COLLECTION_TABLE, {#bump{module=Module},'_'}),
    do_write_module_data(ModuleData, Fd),
    write_module_data(ModList, Fd);
write_module_data([], _Fd) ->
    ok.

do_write_module_data([H|T],Fd) ->
    write(H,Fd),
    do_write_module_data(T,Fd);
do_write_module_data([],_Fd) ->
    ok.

write(Element,Fd) ->
    Bin = term_to_binary(Element,[compressed]),
    case byte_size(Bin) of
	Size when Size > 255 ->
	    SizeBin = term_to_binary({'$size',Size}),
	    ok = file:write(Fd, <<(byte_size(SizeBin)):8,SizeBin/binary,Bin/binary>>);
	Size ->
	    ok = file:write(Fd,<<Size:8,Bin/binary>>)
    end,
    ok.    

%%%--Import--------------------------------------------------------------
do_import_to_table(Fd,ImportFile,Imported) ->
    do_import_to_table(Fd,ImportFile,Imported,[]).
do_import_to_table(Fd,ImportFile,Imported,DontImport) ->
    case get_term(Fd) of
	{file,Module,File} ->
	    case add_imported(Module, File, ImportFile, Imported) of
		{ok,NewImported} ->
		    do_import_to_table(Fd,ImportFile,NewImported,DontImport);
		dont_import ->
		    do_import_to_table(Fd,ImportFile,Imported,
				       [Module|DontImport])
	    end;
	{Key=#bump{module=Module},Val} ->
	    case lists:member(Module,DontImport) of
		false ->
		    insert_in_collection_table(Key,Val);
		true ->
		    ok
	    end,
	    do_import_to_table(Fd,ImportFile,Imported,DontImport);
	eof ->
	    Imported
    end.
	    

get_term(Fd) ->
    case file:read(Fd,1) of
	{ok,<<Size1:8>>} ->
	    {ok,Bin1} = file:read(Fd,Size1),
	    case binary_to_term(Bin1) of
		{'$size',Size2} -> 
		    {ok,Bin2} = file:read(Fd,Size2),
		    binary_to_term(Bin2);
		Term ->
		    Term
	    end;
	eof ->
	    eof
    end.

%%%--Reset---------------------------------------------------------------

%% Reset main node and all remote nodes
do_reset_main_node(Module,Nodes) ->
    reset_counters(Module),
    do_reset_collection_table(Module),
    remote_reset(Module,Nodes).

do_reset_collection_table(Module) ->
    ets:match_delete(?COLLECTION_TABLE, {#bump{module=Module},'_'}).

do_clear(Module) ->
    clear_counters(Module),
    case lists:member(?COLLECTION_TABLE, ets:all()) of
	true ->
	    %% We're on the main node
            ets:match_delete(?BINARY_TABLE, {Module,'_'}),
	    ets:match_delete(?COLLECTION_TABLE, {#bump{module=Module},'_'});
	false ->
	    ok
    end.

not_loaded(Module, unloaded, State) ->
    do_clear(Module),
    remote_unload(State#main_state.nodes,[Module]),
    Compiled = update_compiled([Module],
			       State#main_state.compiled),
    State#main_state{ compiled = Compiled };
not_loaded(_Module,_Else, State) ->
    State.



%%%--Div-----------------------------------------------------------------

escape_lt_and_gt(Rawline,HTML) when HTML =/= true ->
    Rawline;
escape_lt_and_gt(Rawline,_HTML) ->
    escape_lt_and_gt1(Rawline,[]).

escape_lt_and_gt1([$<|T],Acc) ->
    escape_lt_and_gt1(T,[$;,$t,$l,$&|Acc]);
escape_lt_and_gt1([$>|T],Acc) ->
    escape_lt_and_gt1(T,[$;,$t,$g,$&|Acc]);
escape_lt_and_gt1([$&|T],Acc) ->
    escape_lt_and_gt1(T,[$;,$p,$m,$a,$&|Acc]);
escape_lt_and_gt1([],Acc) ->
    lists:reverse(Acc);
escape_lt_and_gt1([H|T],Acc) ->
    escape_lt_and_gt1(T,[H|Acc]).

%%%--Internal functions for parallelization------------------------------
pmap(Fun,List) ->
    NTot = length(List),
    NProcs = erlang:system_info(schedulers) * 2,
    NPerProc = (NTot div NProcs) + 1,
    Mons = pmap_spawn(Fun,NPerProc,List,[]),
    pmap_collect(Mons,[]).

pmap_spawn(_,_,[],Mons) ->
    Mons;
pmap_spawn(Fun,NPerProc,List,Mons) ->
    {L1,L2} = if length(List)>=NPerProc -> lists:split(NPerProc,List);
		 true -> {List,[]} % last chunk
	      end,
    Mon =
	spawn_monitor(
	  fun() ->
		  exit({pmap_done,lists:map(Fun,L1)})
	  end),
    pmap_spawn(Fun,NPerProc,L2,[Mon|Mons]).

pmap_collect([],Acc) ->
    lists:append(Acc);
pmap_collect(Mons,Acc) ->
    receive
	{'DOWN', Ref, process, Pid, {pmap_done,Result}} ->
	    pmap_collect(lists:delete({Pid,Ref},Mons),[Result|Acc]);
	{'DOWN', Ref, process, Pid, Reason} = Down ->
	    case lists:member({Pid,Ref},Mons) of
		true ->
		    %% Something went really wrong - don't hang!
		    exit(Reason);
		false ->
		    %% This should be handled somewhere else
		    self() ! Down,
		    pmap_collect(Mons,Acc)
	    end
    end.

%%%-----------------------------------------------------------------
%%% Decide which encoding to use when analyzing to file.
%%% The target file contains the file path, so if either the file name
%%% encoding or the encoding of the source file is utf8, then we need
%%% to use utf8.
encoding(File) ->
    case file:native_name_encoding() of
        latin1 ->
            case epp:read_encoding(File) of
                none ->
                    epp:default_encoding();
                E ->
                    E
            end;
        utf8 ->
            utf8
    end.

html_encoding(latin1) ->
    "iso-8859-1";
html_encoding(utf8) ->
    "utf-8".

has_native_coverage() ->
    code:coverage_support().