[build] Copy readline module to line_input so we can fork it.

This will aid in correct history expansion (#231) as well as completion
on OS X (#228).

Tested:

- dev build with line_input.so
- Building _bin/oil.ovm{,-dbg} in the repo
- tarball build on my machine (build/test.sh)
- tarball build in Alpine Linux, without readline (test/alpine.sh)

Python-2.7.13/Modules/main.c

@@ -335,14 +335,6 @@ Ovm_Main(int argc, char **argv)
 
     setenv("_OVM_IS_BUNDLE", "1", 1);  // for .zip resources
 
-    // Communicate C build configuration to Python env.
-    // TODO: Could rename back to _OVM_HAVE_READLINE.
-#ifdef HAVE_READLINE
-    setenv("_HAVE_READLINE", "1", 1);
-#else
-    setenv("_HAVE_READLINE", "", 1);
-#endif
-
     // NOTE: I think we need sys.path to find runpy in the first place.  But
     // then runpy mutates sys.path again.
     if (run_self) {

bin/oil.py

@@ -80,12 +80,10 @@ def _tlog(msg):
 value_e = runtime_asdl.value_e
 builtin_e = runtime_asdl.builtin_e
 
-# Set in Modules/main.c.
-HAVE_READLINE = posix.environ.get('_HAVE_READLINE') != ''
-if HAVE_READLINE:
-  import readline
-else:
-  readline = None
+try:
+  import line_input
+except ImportError:
+  line_input = None
 
 log = util.log
 
@@ -146,10 +144,10 @@ def _InitDefaultCompletions(ex, complete_builtin, comp_lookup):
 
 
 def _MaybeWriteHistoryFile(history_filename):
-  if not readline:
+  if not line_input:
     return
   try:
-    readline.write_history_file(history_filename)
+    line_input.write_history_file(history_filename)
   except IOError:
     pass
 
@@ -283,7 +281,7 @@ def ShellMain(lang, argv0, argv, login_shell):
   funcs = {}
 
   fd_state = process.FdState()
-  exec_opts = state.ExecOpts(mem, readline)
+  exec_opts = state.ExecOpts(mem, line_input)
   builtin.SetExecOpts(exec_opts, opts.opt_changes)
   aliases = {}  # feedback between runtime and parser
 
@@ -367,7 +365,7 @@ def ShellMain(lang, argv0, argv, login_shell):
   comp_lookup = completion.Lookup()
 
   builtins = {  # Lookup
-      builtin_e.HISTORY: builtin.History(readline),
+      builtin_e.HISTORY: builtin.History(line_input),
 
       builtin_e.COMPOPT: builtin_comp.CompOpt(comp_state),
       builtin_e.COMPADJUST: builtin_comp.CompAdjust(mem),
@@ -413,8 +411,8 @@ def ShellMain(lang, argv0, argv, login_shell):
   exec_deps.prompt_ev = prompt_ev
   word_ev.prompt_ev = prompt_ev  # HACK for circular deps
 
-  # History evaluation is a no-op if readline is None.
-  hist_ev = reader.HistoryEvaluator(readline, hist_ctx, debug_f)
+  # History evaluation is a no-op if line_input is None.
+  hist_ev = reader.HistoryEvaluator(line_input, hist_ctx, debug_f)
 
   # Calculate ~/.config/oil/oshrc or oilrc
   # Use ~/.config/oil to avoid cluttering the user's home directory.  Some
@@ -470,12 +468,12 @@ def ShellMain(lang, argv0, argv, login_shell):
   if exec_opts.interactive:
     # NOTE: We're using a different evaluator here.  The completion system can
     # also run functions... it gets the Executor through Executor._Complete.
-    if readline:
+    if line_input:
       ev = word_eval.CompletionWordEvaluator(mem, exec_opts, exec_deps, arena)
       progress_f = ui.StatusLine()
       root_comp = completion.RootCompleter(ev, mem, comp_lookup, comp_state,
                                            comp_ctx, progress_f, debug_f)
-      _InitReadline(readline, history_filename, root_comp, debug_f)
+      _InitReadline(line_input, history_filename, root_comp, debug_f)
       _InitDefaultCompletions(ex, complete_builtin, comp_lookup)
 
     # NOTE: Call this AFTER _InitDefaultCompletions.

build/actions.sh

@@ -128,18 +128,18 @@ make-dotd() {
 
 extdecls() {
   for mod in "$@"; do
-    test "$mod" = readline && echo "#ifdef HAVE_READLINE"
+    test "$mod" = line_input && echo "#ifdef HAVE_READLINE"
     echo "extern void init$mod(void);"
-    test "$mod" = readline && echo "#endif"
+    test "$mod" = line_input && echo "#endif"
   done
   return 0  # because test can fail
 }
 
 initbits() {
   for mod in "$@"; do
-    test "$mod" = readline && echo "#ifdef HAVE_READLINE"
+    test "$mod" = line_input && echo "#ifdef HAVE_READLINE"
     echo "    {\"$mod\", init$mod},"
-    test "$mod" = readline && echo "#endif"
+    test "$mod" = line_input && echo "#endif"
   done
   return 0  # because test can fail
 }

build/c_module_srcs.py

@@ -26,7 +26,7 @@ def main(argv):
 
       # Hard-coded special cases for now.
 
-      if mod_name in ('libc', 'fastlex'):  # Our own modules
+      if mod_name in ('libc', 'fastlex', 'line_input'):  # Our own modules
         # Relative to Python-2.7.13 dir
         print('../native/%s.c' % mod_name)
 

build/compile.sh

@@ -202,7 +202,7 @@ build() {
     readline_flags+="-l readline -D HAVE_READLINE"
   else
     # don't fail
-    c_module_src_list=$(grep -v '/readline.c' $abs_c_module_srcs || true)
+    c_module_src_list=$(grep -E -v '/readline.c|/line_input.c' $abs_c_module_srcs || true)
   fi
 
   # $PREFIX comes from ./configure and defaults to /usr/local.

build/cpython_defs.py

@@ -222,6 +222,7 @@ def out(msg, *args):
     # My Own
     'libc.c',
     'fastlex.c',
+    'line_input.c',
 
     'import.c',
     'marshal.c',  # additional filters below

build/dev.sh

@@ -148,6 +148,11 @@ fastlex() {
   native/fastlex_test.py
 }
 
+line-input() {
+  py-ext line_input build/setup_line_input.py
+  native/line_input_test.py "$@"
+}
+
 clean() {
   rm -f --verbose libc.so fastlex.so
   rm -r -f --verbose _devbuild/py-ext
@@ -175,6 +180,7 @@ minimal() {
   asdl/run.sh gen-typed-arith-asdl
 
   pylibc
+  line-input
 }
 
 # Prerequisites: build/codegen.sh {download,install}-re2c

build/setup_line_input.py

@@ -0,0 +1,13 @@
+#!/usr/bin/env python
+from distutils.core import setup, Extension
+
+module = Extension('line_input',
+                    sources = ['native/line_input.c'],
+                    undef_macros = ['NDEBUG'],
+                    libraries = ['readline']
+                    )
+
+setup(name = 'line_input',
+      version = '1.0',
+      description = 'Our readline/libedit binding',
+      ext_modules = [module])

native/fastlex_test.py

@@ -5,10 +5,10 @@
 # You may obtain a copy of the License at
 #
 #   http://www.apache.org/licenses/LICENSE-2.0
-from __future__ import print_function
 """
-libc_test.py: Tests for libc.py
+fastlex_test.py: Tests for fastlex
 """
+from __future__ import print_function
 
 import unittest