library.c

/*
Copyright (C) 2004-2009, Parrot Foundation.
$Id$

=head1 NAME

src/library.c - Interface to Parrot's bytecode library

=head1 DESCRIPTION

This file contains C functions to access Parrot's bytecode library functions,
for include files (via C<.include>), library files (via C<load_bytecode>), and
dynext files (via C<loadlib>).

=head2 Functions

=over 4

=cut

*/

#include "parrot/parrot.h"
#include "parrot/dynext.h"
#include "library.str"

/* HEADERIZER HFILE: include/parrot/library.h */

/* HEADERIZER BEGIN: static */
/* Don't modify between HEADERIZER BEGIN / HEADERIZER END.  Your changes will be lost. */

static void cnv_to_win32_filesep(ARGMOD(STRING *path))
        __attribute__nonnull__(1)
        FUNC_MODIFIES(*path);

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static PMC* get_search_paths(PARROT_INTERP, enum_lib_paths which)
        __attribute__nonnull__(1);

PARROT_PURE_FUNCTION
static int is_abs_path(ARGIN(const STRING *file))
        __attribute__nonnull__(1);

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static STRING* path_append(PARROT_INTERP,
    ARGMOD(STRING *l_path),
    ARGMOD(STRING *r_path))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        FUNC_MODIFIES(*l_path)
        FUNC_MODIFIES(*r_path);

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static STRING* path_concat(PARROT_INTERP,
    ARGMOD(STRING *l_path),
    ARGMOD(STRING *r_path))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        __attribute__nonnull__(3)
        FUNC_MODIFIES(*l_path)
        FUNC_MODIFIES(*r_path);

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static STRING* path_finalize(PARROT_INTERP, ARGMOD(STRING *path))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        FUNC_MODIFIES(*path);

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static STRING* path_guarantee_trailing_separator(PARROT_INTERP,
    ARGMOD(STRING *path))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        FUNC_MODIFIES(*path);

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static STRING* try_bytecode_extensions(PARROT_INTERP, ARGMOD(STRING* path))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        FUNC_MODIFIES(* path);

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static STRING* try_load_path(PARROT_INTERP, ARGMOD(STRING* path))
        __attribute__nonnull__(1)
        __attribute__nonnull__(2)
        FUNC_MODIFIES(* path);

#define ASSERT_ARGS_cnv_to_win32_filesep __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(path))
#define ASSERT_ARGS_get_search_paths __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(interp))
#define ASSERT_ARGS_is_abs_path __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(file))
#define ASSERT_ARGS_path_append __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(interp) \
    , PARROT_ASSERT_ARG(l_path) \
    , PARROT_ASSERT_ARG(r_path))
#define ASSERT_ARGS_path_concat __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(interp) \
    , PARROT_ASSERT_ARG(l_path) \
    , PARROT_ASSERT_ARG(r_path))
#define ASSERT_ARGS_path_finalize __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(interp) \
    , PARROT_ASSERT_ARG(path))
#define ASSERT_ARGS_path_guarantee_trailing_separator \
     __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(interp) \
    , PARROT_ASSERT_ARG(path))
#define ASSERT_ARGS_try_bytecode_extensions __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(interp) \
    , PARROT_ASSERT_ARG(path))
#define ASSERT_ARGS_try_load_path __attribute__unused__ int _ASSERT_ARGS_CHECK = (\
       PARROT_ASSERT_ARG(interp) \
    , PARROT_ASSERT_ARG(path))
/* Don't modify between HEADERIZER BEGIN / HEADERIZER END.  Your changes will be lost. */
/* HEADERIZER END: static */


/*

=item C<void parrot_init_library_paths(PARROT_INTERP)>

Create an array of StringArrays with library searchpaths and shared
extension used for loading various files at runtime. The created
structures looks like this:

  lib_paths = [
    [ "runtime/parrot/include", ... ],   # paths for .include 'file'
    [ "runtime/parrot/library", ... ],   # paths for load_bytecode
    [ "runtime/parrot/dynext", ... ],    # paths for loadlib
    [ "languages", ... ],                # paths for languages
    [ ".so", ... ]                       # list of shared extensions
  ]

If the platform defines

  #define PARROT_PLATFORM_LIB_PATH_INIT_HOOK the_init_hook

it will be called as a function with this prototype:

  void the_init_hook(PARROT_INTERP, PMC *lib_paths);

Platform code may add, delete, or replace search path entries as needed. See
also F<include/parrot/library.h> for C<enum_lib_paths>.

=cut

*/

void
parrot_init_library_paths(PARROT_INTERP)
{
    ASSERT_ARGS(parrot_init_library_paths)
    PMC    *paths;
    STRING *entry;
    STRING *versionlib      = NULL;
    STRING *builddir        = NULL;
    PMC * const iglobals    = interp->iglobals;
    PMC * const config_hash = VTABLE_get_pmc_keyed_int(interp, iglobals,
                                (INTVAL)IGLOBALS_CONFIG_HASH);

    /* create the lib_paths array */
    PMC * const lib_paths   = Parrot_pmc_new_init_int(interp,
            enum_class_FixedPMCArray, PARROT_LIB_PATH_SIZE);
    VTABLE_set_pmc_keyed_int(interp, iglobals,
            IGLOBALS_LIB_PATHS, lib_paths);

    if (VTABLE_elements(interp, config_hash)) {
        STRING * const libkey      = CONST_STRING(interp, "libdir");
        STRING * const verkey      = CONST_STRING(interp, "versiondir");
        STRING * const builddirkey = CONST_STRING(interp, "build_dir");
        STRING * const installed   = CONST_STRING(interp, "installed");

        versionlib = VTABLE_get_string_keyed_str(interp, config_hash, libkey);
        entry      = VTABLE_get_string_keyed_str(interp, config_hash, verkey);
        versionlib = Parrot_str_concat(interp, versionlib, entry);

        if (!VTABLE_get_integer_keyed_str(interp, config_hash, installed))
            builddir = VTABLE_get_string_keyed_str(interp,
                                config_hash, builddirkey);
    }

    /* each is an array of strings */
    /* define include paths */
    paths = Parrot_pmc_new(interp, enum_class_ResizableStringArray);
    VTABLE_set_pmc_keyed_int(interp, lib_paths,
            PARROT_LIB_PATH_INCLUDE, paths);
    { /* EXPERIMENTAL: add include path from environment */
        const char *envvar = Parrot_getenv(interp,
                                           Parrot_str_new_constant(interp, "PARROT_INCLUDE"));
        if (envvar != NULL  && envvar[0]) {
            entry = Parrot_str_new(interp, envvar, 0);
            VTABLE_push_string(interp, paths, entry);
        }
    }
    if (!STRING_IS_NULL(builddir)) {
        entry = Parrot_str_concat(interp, builddir, CONST_STRING(interp, "/"));
        VTABLE_push_string(interp, paths, entry);
        entry = Parrot_str_concat(interp, builddir, CONST_STRING(interp, "/runtime/parrot/include/"));
        VTABLE_push_string(interp, paths, entry);
    }
    entry = CONST_STRING(interp, "./");
    VTABLE_push_string(interp, paths, entry);
    if (!STRING_IS_NULL(versionlib)) {
        entry = Parrot_str_concat(interp, versionlib, CONST_STRING(interp, "/include/"));
        VTABLE_push_string(interp, paths, entry);
    }

    /* define library paths */
    paths = Parrot_pmc_new(interp, enum_class_ResizableStringArray);
    VTABLE_set_pmc_keyed_int(interp, lib_paths,
            PARROT_LIB_PATH_LIBRARY, paths);
    { /* EXPERIMENTAL: add library path from environment */
        const char *envvar = Parrot_getenv(interp,
                                           Parrot_str_new_constant(interp, "PARROT_LIBRARY"));
        if (envvar != NULL && envvar[0]) {
            entry = Parrot_str_new(interp, envvar, 0);
            VTABLE_push_string(interp, paths, entry);
        }
    }
    if (!STRING_IS_NULL(builddir)) {
        entry = Parrot_str_concat(interp, builddir, CONST_STRING(interp, "/runtime/parrot/library/"));
        VTABLE_push_string(interp, paths, entry);
    }
    entry = CONST_STRING(interp, "./");
    VTABLE_push_string(interp, paths, entry);
    if (!STRING_IS_NULL(versionlib)) {
        entry = Parrot_str_concat(interp, versionlib, CONST_STRING(interp, "/library/"));
        VTABLE_push_string(interp, paths, entry);
    }

    /* define languages paths */
    paths = Parrot_pmc_new(interp, enum_class_ResizableStringArray);
    VTABLE_set_pmc_keyed_int(interp, lib_paths,
            PARROT_LIB_PATH_LANG, paths);
    if (!STRING_IS_NULL(builddir)) {
        entry = Parrot_str_concat(interp, builddir, CONST_STRING(interp, "/runtime/parrot/languages/"));
        VTABLE_push_string(interp, paths, entry);
    }
    entry = CONST_STRING(interp, "./");
    VTABLE_push_string(interp, paths, entry);
    if (!STRING_IS_NULL(versionlib)) {
        entry = Parrot_str_concat(interp, versionlib, CONST_STRING(interp, "/languages/"));
        VTABLE_push_string(interp, paths, entry);
    }

    /* define dynext paths */
    paths = Parrot_pmc_new(interp, enum_class_ResizableStringArray);
    VTABLE_set_pmc_keyed_int(interp, lib_paths,
            PARROT_LIB_PATH_DYNEXT, paths);
    if (!STRING_IS_NULL(builddir)) {
        entry = Parrot_str_concat(interp, builddir, CONST_STRING(interp, "/runtime/parrot/dynext/"));
        VTABLE_push_string(interp, paths, entry);
    }
    entry = CONST_STRING(interp, "dynext/");
    VTABLE_push_string(interp, paths, entry);
    if (!STRING_IS_NULL(versionlib)) {
        entry = Parrot_str_concat(interp, versionlib, CONST_STRING(interp, "/dynext/"));
        VTABLE_push_string(interp, paths, entry);
    }

    /* shared exts */
    paths = Parrot_pmc_new(interp, enum_class_ResizableStringArray);
    VTABLE_set_pmc_keyed_int(interp, lib_paths,
            PARROT_LIB_DYN_EXTS, paths);
    /* no CONST_STRING here - the c2str.pl preprocessor needs "real strs" */
    entry = Parrot_str_new_constant(interp, PARROT_LOAD_EXT);
    VTABLE_push_string(interp, paths, entry);
    /* OS/X has .dylib and .bundle */
    if (!STREQ(PARROT_LOAD_EXT, PARROT_SHARE_EXT)) {
        entry = Parrot_str_new_constant(interp, PARROT_SHARE_EXT);
        VTABLE_push_string(interp, paths, entry);
    }

#ifdef PARROT_PLATFORM_LIB_PATH_INIT_HOOK
    PARROT_PLATFORM_LIB_PATH_INIT_HOOK(interp, lib_paths);
#endif
}

/*

=item C<static PMC* get_search_paths(PARROT_INTERP, enum_lib_paths which)>

Return lib_paths as array of StringArrays with library searchpaths and shared
extension used for loading various files at runtime.
The structure looks like this:

  lib_paths = [
    [ "runtime/parrot/include", ... ],   # paths for .include 'file'
    [ "runtime/parrot/library", ... ],   # paths for load_bytecode
    [ "runtime/parrot/dynext", ... ],    # paths for loadlib
    [ "languages", ... ],                # paths for languages
    [ ".so", ... ]                       # list of shared extensions
  ]

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static PMC*
get_search_paths(PARROT_INTERP, enum_lib_paths which)
{
    ASSERT_ARGS(get_search_paths)
    PMC * const iglobals = interp->iglobals;
    PMC * const lib_paths = VTABLE_get_pmc_keyed_int(interp, iglobals,
            IGLOBALS_LIB_PATHS);
    return VTABLE_get_pmc_keyed_int(interp, lib_paths, which);
}

static const char path_separator = '/';

#ifdef WIN32

static const char win32_path_separator = '\\';

#endif

/*

=item C<static int is_abs_path(const STRING *file)>

Determines whether a file name given by a fixed-8 or utf8 C<STRING> is an
absolute file name. Returns C<1> if the filename is absolute, returns C<0>
otherwise.

=cut

*/

PARROT_PURE_FUNCTION
static int
is_abs_path(ARGIN(const STRING *file))
{
    ASSERT_ARGS(is_abs_path)
    const char * const file_name = (const char *)file->strstart;
    if (file->strlen <= 1)
        return 0;
    PARROT_ASSERT(STRING_max_bytes_per_codepoint(file) == 1 ||
            file->encoding == Parrot_utf8_encoding_ptr);

    /* XXX  ../foo, ./bar */
    if (file_name[0] == path_separator
#ifdef WIN32
            || (file_name[0] == win32_path_separator ||
            (isalpha((unsigned char)file_name[0]) && file->strlen > 2 &&
             (strncmp(file_name+1, ":\\", 2) == 0 ||
              strncmp(file_name+1, ":/",  2) == 0)))
#endif
            /* no space before closing paren */)
        {
            return 1;
        }
    return 0;
}


#ifdef WIN32

/*

=item C<static void cnv_to_win32_filesep(STRING *path)>

Converts a path with forward slashes to one with backward slashes.

=cut

*/

static void
cnv_to_win32_filesep(ARGMOD(STRING *path))
{
    ASSERT_ARGS(cnv_to_win32_filesep)
    char *cnv = path->strstart;

    while ((cnv = strchr(cnv, path_separator)) != NULL)
        *cnv = win32_path_separator;
}

#endif

/*

=item C<static STRING* path_finalize(PARROT_INTERP, STRING *path)>

Ensures the given STRING C<path> has a C-style NULL character at the end. The
length of the string is not increased to account for this NULL, however. In
WIN32 systems, the path separator is switched from the unix-style "/" to the
Windows-style "\".

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static STRING*
path_finalize(PARROT_INTERP, ARGMOD(STRING *path))
{
    ASSERT_ARGS(path_finalize)

    /* TODO create a string API that just does that
     *      a lot of ICU lib functions also need 0-terminated strings
     *      the goal is just to have for sure an invisible 0 at end
     */

    STRING * const nul = string_chr(interp, '\0');

    path = Parrot_str_concat(interp, path, nul);
    --path->bufused;
    --path->strlen;

#ifdef WIN32
    cnv_to_win32_filesep(path);
#endif

    return path;
}

/*

=item C<static STRING* path_guarantee_trailing_separator(PARROT_INTERP, STRING
*path)>

unary path argument. the path string will have a
trailing path-separator appended if it is not
there already.

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static STRING*
path_guarantee_trailing_separator(PARROT_INTERP, ARGMOD(STRING *path))
{
    ASSERT_ARGS(path_guarantee_trailing_separator)
    STRING * const path_separator_string = string_chr(interp, path_separator);

    /* make sure the path has a trailing slash before appending the file */
    if (Parrot_str_indexed(interp, path , path->strlen - 1)
         != Parrot_str_indexed(interp, path_separator_string, 0))
        path = Parrot_str_concat(interp, path , path_separator_string);

    return path;
}

/*

=item C<static STRING* path_append(PARROT_INTERP, STRING *l_path, STRING
*r_path)>

binary path arguments, the left arg is modified.
a trailing separator is guaranteed for the left
argument and the right argument is appended

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static STRING*
path_append(PARROT_INTERP, ARGMOD(STRING *l_path), ARGMOD(STRING *r_path))
{
    ASSERT_ARGS(path_append)
    l_path = path_guarantee_trailing_separator(interp, l_path);
    l_path = Parrot_str_concat(interp, l_path, r_path);

    return l_path;
}

/*

=item C<static STRING* path_concat(PARROT_INTERP, STRING *l_path, STRING
*r_path)>

binary path arguments. A new string is created
that is the concatenation of the two path components
with a path-separator.

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CANNOT_RETURN_NULL
static STRING*
path_concat(PARROT_INTERP, ARGMOD(STRING *l_path), ARGMOD(STRING *r_path))
{
    ASSERT_ARGS(path_concat)
    STRING* join;

    join = path_guarantee_trailing_separator(interp, l_path);
    join = Parrot_str_concat(interp, join, r_path);

    return join;
}

/*

=item C<static STRING* try_load_path(PARROT_INTERP, STRING* path)>

Attempts to load a file with name C<path>. If the file is successfully located,
the finalized name of the file is returned as a STRING. Otherwise, returns
NULL.

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static STRING*
try_load_path(PARROT_INTERP, ARGMOD(STRING* path))
{
    ASSERT_ARGS(try_load_path)
    STRING * const final = path_finalize(interp, path);

    if (Parrot_stat_info_intval(interp, final, STAT_EXISTS)) {
        return final;
    }

    return NULL;
}

/*

=item C<static STRING* try_bytecode_extensions(PARROT_INTERP, STRING* path)>

Guess extensions, so that the user can drop the extensions
leaving it up to the build process/install whether or not
a .pbc, .pasm or a .pir file is used.

=cut

*/

PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
static STRING*
try_bytecode_extensions(PARROT_INTERP, ARGMOD(STRING* path))
{
    ASSERT_ARGS(try_bytecode_extensions)
    STRING *test_path, *result;
    STRING * const bytecode_extension = CONST_STRING(interp, ".pbc");
    STRING * const pir_extension      = CONST_STRING(interp, ".pir");
    STRING * const pasm_extension     = CONST_STRING(interp, ".pasm");

    test_path = path;

    /* First try the path as given. */
    result = try_load_path(interp, test_path);
    if (result)
        return result;

    /*
      If the original requested file doesn't exist, try it with a
      different extension. A requested PIR or PASM file will check for a
      corresponding bytecode file. A requested bytecode file will check
      first for a corresponding PIR file, then for a PASM file.
    */

    if (!STRING_IS_NULL(test_path)) {
        if (Parrot_str_byte_length(interp, test_path) > 4) {
            STRING *orig_ext = Parrot_str_substr(interp, test_path, -4, 4);
            /* First try substituting .pbc for the .pir extension */
            if (Parrot_str_equal(interp, orig_ext, pir_extension)) {
                STRING * const without_ext = Parrot_str_chopn(interp, test_path, 4);
                test_path = Parrot_str_concat(interp, without_ext, bytecode_extension);
                result = try_load_path(interp, test_path);
                if (result)
                    return result;
            }
            /* Next try substituting .pir, then .pasm for the .pbc extension */
            else if (Parrot_str_equal(interp, orig_ext, bytecode_extension)) {
                STRING * const without_ext = Parrot_str_chopn(interp, test_path, 4);
                test_path = Parrot_str_concat(interp, without_ext, pir_extension);
                result = try_load_path(interp, test_path);
                if (result)
                    return result;

                test_path = Parrot_str_concat(interp, without_ext, pasm_extension);
                result = try_load_path(interp, test_path);
                if (result)
                    return result;
            }

        }

        /* Finally, try substituting .pbc for the .pasm extension. */
        if (Parrot_str_byte_length(interp, test_path) > 5) {
            STRING * const orig_ext = Parrot_str_substr(interp, test_path, -5, 5);
            if (Parrot_str_equal(interp, orig_ext, pasm_extension)) {
                STRING * const without_ext = Parrot_str_chopn(interp, test_path, 5);
                test_path = Parrot_str_concat(interp, without_ext, bytecode_extension);
                result = try_load_path(interp, test_path);
                if (result)
                    return result;
            }
        }
    }

    return NULL;
}

/*

=item C<void Parrot_lib_add_path(PARROT_INTERP, STRING *path_str, enum_lib_paths
which)>

Add a path to the library searchpath of the given type (passing in a STRING).

=cut

*/

PARROT_EXPORT
void
Parrot_lib_add_path(PARROT_INTERP,
        ARGIN(STRING *path_str),
        enum_lib_paths which)
{
    ASSERT_ARGS(Parrot_lib_add_path)
    PMC * const iglobals = interp->iglobals;
    PMC * const lib_paths = VTABLE_get_pmc_keyed_int(interp, iglobals,
        IGLOBALS_LIB_PATHS);
    PMC * const paths = VTABLE_get_pmc_keyed_int(interp, lib_paths, which);
    VTABLE_unshift_string(interp, paths, path_str);
}

/*

=item C<void Parrot_lib_add_path_from_cstring(PARROT_INTERP, const char *path,
enum_lib_paths which)>

Add a path to the library searchpath of the given type (passing in a C string).

=cut

*/

PARROT_EXPORT
void
Parrot_lib_add_path_from_cstring(PARROT_INTERP,
        ARGIN(const char *path),
        enum_lib_paths which)
{
    ASSERT_ARGS(Parrot_lib_add_path_from_cstring)
    STRING * const path_str = Parrot_str_new(interp, path, 0);
    Parrot_lib_add_path(interp, path_str, which);
}

/*

=item C<STRING* Parrot_locate_runtime_file_str(PARROT_INTERP, STRING *file,
enum_runtime_ft type)>

Locate the full path for C<file_name> and the given file type(s).

The C<enum_runtime_ft type> is one or more of the types defined in
F<include/parrot/library.h>.

=cut

*/

PARROT_EXPORT
PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
STRING*
Parrot_locate_runtime_file_str(PARROT_INTERP, ARGMOD(STRING *file),
        enum_runtime_ft type)
{
    ASSERT_ARGS(Parrot_locate_runtime_file_str)
    STRING *prefix;
    STRING *full_name;
    PMC    *paths;
    INTVAL  i, n;

    /* if this is an absolute path return it as is */
    if (is_abs_path(file))
        return file;

    if (type & PARROT_RUNTIME_FT_LANG)
        paths = get_search_paths(interp, PARROT_LIB_PATH_LANG);
    else if (type & PARROT_RUNTIME_FT_DYNEXT)
        paths = get_search_paths(interp, PARROT_LIB_PATH_DYNEXT);
    else if (type & (PARROT_RUNTIME_FT_PBC | PARROT_RUNTIME_FT_SOURCE))
        paths = get_search_paths(interp, PARROT_LIB_PATH_LIBRARY);
    else
        paths = get_search_paths(interp, PARROT_LIB_PATH_INCLUDE);

    prefix = Parrot_get_runtime_path(interp);
    n = VTABLE_elements(interp, paths);

    for (i = 0; i < n; ++i) {
        STRING * const path = VTABLE_get_string_keyed_int(interp, paths, i);
        STRING *found_name;

        full_name = path_append(interp, path, file);

        found_name =
            (type & PARROT_RUNTIME_FT_DYNEXT)
                ? try_load_path(interp, full_name)
                : try_bytecode_extensions(interp, full_name);

        if (found_name)
            return found_name;

        if (Parrot_str_byte_length(interp, prefix) && !is_abs_path(path)) {
            full_name = path_concat(interp, prefix, full_name);

            found_name =
                (type & PARROT_RUNTIME_FT_DYNEXT)
                    ? try_load_path(interp, full_name)
                    : try_bytecode_extensions(interp, full_name);

            if (found_name)
                return found_name;
        }
    }

    full_name =
        (type & PARROT_RUNTIME_FT_DYNEXT)
            ? try_load_path(interp, file)
            : try_bytecode_extensions(interp, file);

    return full_name;
}

/*

=item C<char* Parrot_locate_runtime_file(PARROT_INTERP, const char *file_name,
enum_runtime_ft type)>

Locate the full path for C<file_name> and the given file type(s). If
successful, returns a C-string allocated with C<Parrot_str_to_cstring> or
NULL otherwise.  Remember to free the string with C<Parrot_str_free_cstring()>.

If successful, the returned STRING is 0-terminated so that
C<result-E<gt>strstart> is usable as B<const char*> c-string for C library
functions like fopen(3).  This is the preferred API function.

The C<enum_runtime_ft type> is one or more of the types defined in
F<include/parrot/library.h>.

=cut

*/


PARROT_EXPORT
PARROT_WARN_UNUSED_RESULT
PARROT_CAN_RETURN_NULL
PARROT_MALLOC
char*
Parrot_locate_runtime_file(PARROT_INTERP, ARGIN(const char *file_name),
        enum_runtime_ft type)
{
    ASSERT_ARGS(Parrot_locate_runtime_file)
    STRING * const file   = Parrot_str_new(interp, file_name, 0);
    STRING * const result = Parrot_locate_runtime_file_str(interp, file, type);
    /*
     * XXX valgrind shows e.g.
     *     invalid read of size 8 inside a string of length 69
     *     at position 64
     *     it seems that dlopen accesses words beyond the string end
     *
     *     see also the log at #37814
     */
    return result ? Parrot_str_to_cstring(interp, result) : NULL;
}

/*

=item C<STRING * Parrot_get_runtime_path(PARROT_INTERP)>

Return a string for the runtime prefix.

=cut

*/

PARROT_EXPORT
PARROT_CANNOT_RETURN_NULL
STRING *
Parrot_get_runtime_path(PARROT_INTERP)
{
    ASSERT_ARGS(Parrot_get_runtime_path)
    char * const env = Parrot_getenv(interp, CONST_STRING(interp, "PARROT_RUNTIME"));
    STRING *result;

    if (env)
    {
        result = Parrot_str_new(interp, env, 0);
    }
    else {
        PMC    * const config_hash =
            VTABLE_get_pmc_keyed_int(interp, interp->iglobals, (INTVAL) IGLOBALS_CONFIG_HASH);

        if (VTABLE_elements(interp, config_hash)) {
            STRING * const key = CONST_STRING(interp, "prefix");
            result = VTABLE_get_string_keyed_str(interp, config_hash, key);
        }
        else
            result = CONST_STRING(interp, ".");
    }
    return result;
}

/*

=item C<STRING * parrot_split_path_ext(PARROT_INTERP, STRING *in, STRING
**wo_ext, STRING **ext)>

Split the pathstring C<in> into <path><filestem><ext>. Return the
C<filestem> of the pathstring. Set C<wo_ext> to the part without
extension and C<ext> to the extension or NULL.

=cut

*/

PARROT_IGNORABLE_RESULT
PARROT_CANNOT_RETURN_NULL
STRING *
parrot_split_path_ext(PARROT_INTERP, ARGMOD(STRING *in),
        ARGOUT(STRING **wo_ext), ARGOUT(STRING **ext))
{
    ASSERT_ARGS(parrot_split_path_ext)

    /* This is a quick fix for TT #65
     * TODO: redo it with the string reimplementation
     */
    STRING * const slash1 = Parrot_str_new_init(interp, "/", 1,
            in->encoding, PObj_external_FLAG|PObj_constant_FLAG);
    STRING * const slash2 = Parrot_str_new_init(interp, "\\", 1,
            in->encoding, PObj_external_FLAG|PObj_constant_FLAG);
    STRING * const dot    = Parrot_str_new_init(interp, ".", 1,
            in->encoding, PObj_external_FLAG|PObj_constant_FLAG);

    const INTVAL len = Parrot_str_byte_length(interp, in);
    STRING *stem;
    INTVAL pos_sl, pos_dot;

    pos_sl = STRING_rindex(interp, in, slash1, len);
    if (pos_sl == -1)
        pos_sl = STRING_rindex(interp, in, slash2, len);
    pos_dot = STRING_rindex(interp, in, dot, len);

    /* ignore dot in directory name */
    if (pos_dot != -1 && pos_dot < pos_sl)
        pos_dot = -1;

    ++pos_dot;
    ++pos_sl;
    if (pos_sl && pos_dot) {
        stem = Parrot_str_substr(interp, in, pos_sl, pos_dot - pos_sl - 1);
        *wo_ext = Parrot_str_substr(interp, in, 0, pos_dot - 1);
        *ext = Parrot_str_substr(interp, in, pos_dot, len - pos_dot);
    }
    else if (pos_dot) {
        stem = Parrot_str_substr(interp, in, 0, pos_dot - 1);
        *wo_ext = stem;
        *ext = Parrot_str_substr(interp, in, pos_dot, len - pos_dot);
    }
    else if (pos_sl) {
        stem = Parrot_str_substr(interp, in, pos_sl, len - pos_sl);
        *wo_ext = in;
        *ext = NULL;
    }
    else {
        stem = in;
        *wo_ext = stem;
        *ext = NULL;
    }
    return stem;
}

/*

=back

=head1 SEE ALSO

F<include/parrot/library.h>

=cut

*/


/*
 * Local variables:
 *   c-file-style: "parrot"
 * End:
 * vim: expandtab shiftwidth=4:
 */