text: /*
   * Copyright (C) the libgit2 contributors. All rights reserved.
   *
   * This file is part of libgit2, distributed under the GNU GPL v2 with
   * a Linking Exception. For full terms see the included COPYING file.
   */
  
  #include "common.h"
  #include "sysdir.h"
  #include "global.h"
  #include "buffer.h"
  #include "path.h"
  #include <ctype.h>
  #if GIT_WIN32
  #include "win32/findfile.h"
  #endif
  
  static int git_sysdir_guess_system_dirs(git_buf *out)
  {
  #ifdef GIT_WIN32
  	return git_win32__find_system_dirs(out, L"etc\\");
  #else
  	return git_buf_sets(out, "/etc");
  #endif
  }
  
  static int git_sysdir_guess_global_dirs(git_buf *out)
  {
  #ifdef GIT_WIN32
  	return git_win32__find_global_dirs(out);
  #else
  	return git_buf_sets(out, getenv("HOME"));
  #endif
  }
  
  static int git_sysdir_guess_xdg_dirs(git_buf *out)
  {
  #ifdef GIT_WIN32
  	return git_win32__find_xdg_dirs(out);
  #else
  	const char *env = NULL;
  
  	if ((env = getenv("XDG_CONFIG_HOME")) != NULL)
  		return git_buf_joinpath(out, env, "git");
  	else if ((env = getenv("HOME")) != NULL)
  		return git_buf_joinpath(out, env, ".config/git");
  
  	git_buf_clear(out);
  	return 0;
  #endif
  }
  
  static int git_sysdir_guess_template_dirs(git_buf *out)
  {
  #ifdef GIT_WIN32
  	return git_win32__find_system_dirs(out, L"share\\git-core\\templates");
  #else
  	return git_buf_sets(out, "/usr/share/git-core/templates");
  #endif
  }
  
  typedef int (*git_sysdir_guess_cb)(git_buf *out);
  
  static git_buf git_sysdir__dirs[GIT_SYSDIR__MAX] =
  	{ GIT_BUF_INIT, GIT_BUF_INIT, GIT_BUF_INIT, GIT_BUF_INIT };
  
  static git_sysdir_guess_cb git_sysdir__dir_guess[GIT_SYSDIR__MAX] = {
  	git_sysdir_guess_system_dirs,
  	git_sysdir_guess_global_dirs,
  	git_sysdir_guess_xdg_dirs,
  	git_sysdir_guess_template_dirs,
  };
  
  static int git_sysdir__dirs_shutdown_set = 0;
  
  int git_sysdir_global_init(void)
  {
  	git_sysdir_t i;
  	const git_buf *path;
  	int error = 0;
  
  	for (i = 0; !error && i < GIT_SYSDIR__MAX; i++)
  		error = git_sysdir_get(&path, i);
  
  	return error;
  }
  
  void git_sysdir_global_shutdown(void)
  {
  	int i;
  	for (i = 0; i < GIT_SYSDIR__MAX; ++i)
  		git_buf_free(&git_sysdir__dirs[i]);
  
  	git_sysdir__dirs_shutdown_set = 0;
  }
  
  static int git_sysdir_check_selector(git_sysdir_t which)
  {
  	if (which < GIT_SYSDIR__MAX)
  		return 0;
  
  	giterr_set(GITERR_INVALID, "config directory selector out of range");
  	return -1;
  }
  
  
  int git_sysdir_get(const git_buf **out, git_sysdir_t which)
  {
  	assert(out);
  
  	*out = NULL;
  
  	GITERR_CHECK_ERROR(git_sysdir_check_selector(which));
  
  	if (!git_buf_len(&git_sysdir__dirs[which])) {
  		/* prepare shutdown if we're going to need it */
  		if (!git_sysdir__dirs_shutdown_set) {
  			git__on_shutdown(git_sysdir_global_shutdown);
  			git_sysdir__dirs_shutdown_set = 1;
  		}
  
  		GITERR_CHECK_ERROR(
  			git_sysdir__dir_guess[which](&git_sysdir__dirs[which]));
  	}
  
  	*out = &git_sysdir__dirs[which];
  	return 0;
  }
  
  int git_sysdir_get_str(
  	char *out,
  	size_t outlen,
  	git_sysdir_t which)
  {
  	const git_buf *path = NULL;
  
  	GITERR_CHECK_ERROR(git_sysdir_check_selector(which));
  	GITERR_CHECK_ERROR(git_sysdir_get(&path, which));
  
  	if (!out || path->size >= outlen) {
  		giterr_set(GITERR_NOMEMORY, "Buffer is too short for the path");
  		return GIT_EBUFS;
  	}
  
  	git_buf_copy_cstr(out, outlen, path);
  	return 0;
  }
  
  #define PATH_MAGIC "$PATH"
  
  int git_sysdir_set(git_sysdir_t which, const char *search_path)
  {
  	const char *expand_path = NULL;
  	git_buf merge = GIT_BUF_INIT;
  
  	GITERR_CHECK_ERROR(git_sysdir_check_selector(which));
  
  	if (search_path != NULL)
  		expand_path = strstr(search_path, PATH_MAGIC);
  
  	/* init with default if not yet done and needed (ignoring error) */
  	if ((!search_path || expand_path) &&
  		!git_buf_len(&git_sysdir__dirs[which]))
  		git_sysdir__dir_guess[which](&git_sysdir__dirs[which]);
  
  	/* if $PATH is not referenced, then just set the path */
  	if (!expand_path)
  		return git_buf_sets(&git_sysdir__dirs[which], search_path);
  
  	/* otherwise set to join(before $PATH, old value, after $PATH) */
  	if (expand_path > search_path)
  		git_buf_set(&merge, search_path, expand_path - search_path);
  
  	if (git_buf_len(&git_sysdir__dirs[which]))
  		git_buf_join(&merge, GIT_PATH_LIST_SEPARATOR,
  			merge.ptr, git_sysdir__dirs[which].ptr);
  
  	expand_path += strlen(PATH_MAGIC);
  	if (*expand_path)
  		git_buf_join(&merge, GIT_PATH_LIST_SEPARATOR, merge.ptr, expand_path);
  
  	git_buf_swap(&git_sysdir__dirs[which], &merge);
  	git_buf_free(&merge);
  
  	return git_buf_oom(&git_sysdir__dirs[which]) ? -1 : 0;
  }
  
  static int git_sysdir_find_in_dirlist(
  	git_buf *path,
  	const char *name,
  	git_sysdir_t which,
  	const char *label)
  {
  	size_t len;
  	const char *scan, *next = NULL;
  	const git_buf *syspath;
  
  	GITERR_CHECK_ERROR(git_sysdir_get(&syspath, which));
  	if (!syspath || !git_buf_len(syspath))
  		goto done;
  
  	for (scan = git_buf_cstr(syspath); scan; scan = next) {
  		/* find unescaped separator or end of string */
  		for (next = scan; *next; ++next) {
  			if (*next == GIT_PATH_LIST_SEPARATOR &&
  				(next <= scan || next[-1] != '\\'))
  				break;
  		}
  
  		len = (size_t)(next - scan);
  		next = (*next ? next + 1 : NULL);
  		if (!len)
  			continue;
  
  		GITERR_CHECK_ERROR(git_buf_set(path, scan, len));
  		if (name)
  			GITERR_CHECK_ERROR(git_buf_joinpath(path, path->ptr, name));
  
  		if (git_path_exists(path->ptr))
  			return 0;
  	}
  
  done:
  	git_buf_free(path);
  	giterr_set(GITERR_OS, "The %s file '%s' doesn't exist", label, name);
  	return GIT_ENOTFOUND;
  }
  
  int git_sysdir_find_system_file(git_buf *path, const char *filename)
  {
  	return git_sysdir_find_in_dirlist(
  		path, filename, GIT_SYSDIR_SYSTEM, "system");
  }
  
  int git_sysdir_find_global_file(git_buf *path, const char *filename)
  {
  	return git_sysdir_find_in_dirlist(
  		path, filename, GIT_SYSDIR_GLOBAL, "global");
  }
  
  int git_sysdir_find_xdg_file(git_buf *path, const char *filename)
  {
  	return git_sysdir_find_in_dirlist(
  		path, filename, GIT_SYSDIR_XDG, "global/xdg");
  }
  
  int git_sysdir_find_template_dir(git_buf *path)
  {
  	return git_sysdir_find_in_dirlist(
  		path, NULL, GIT_SYSDIR_TEMPLATE, "template");
  }
  
  