#define DISABLE_SIGN_COMPARE_WARNINGS

#include "git-compat-util.h"

#include "gettext.h"

#include "setup.h"

#include "symlinks.h"

static int threaded_check_leading_path(struct cache_def *cache, const char *name,

               int len, int warn_on_lstat_err);

static int threaded_has_dirs_only_path(struct cache_def *cache, const char *name, int len, int prefix_len);

/*

 * Returns the length (on a path component basis) of the longest

 * common prefix match of 'name_a' and 'name_b'.

 */

static int longest_path_match(const char *name_a, int len_a,

            const char *name_b, int len_b,

            int *previous_slash)

{

  int max_len, match_len = 0, match_len_prev = 0, i = 0;

  max_len = len_a < len_b ? len_a : len_b;

  while (i < max_len && name_a[i] == name_b[i]) {

    if (name_a[i] == '/') {

      match_len_prev = match_len;

      match_len = i;

    }

    i++;

  }

  /*

   * Is 'name_b' a substring of 'name_a', the other way around,

   * or is 'name_a' and 'name_b' the exact same string?

   */

  if (i >= max_len && ((len_a > len_b && name_a[len_b] == '/') ||

           (len_a < len_b && name_b[len_a] == '/') ||

           (len_a == len_b))) {

    match_len_prev = match_len;

    match_len = i;

  }

  *previous_slash = match_len_prev;

  return match_len;

}

static struct cache_def default_cache = CACHE_DEF_INIT;

static inline void reset_lstat_cache(struct cache_def *cache)

{

  strbuf_reset(&cache->path);

  cache->flags = 0;

  /*

   * The track_flags and prefix_len_stat_func members is only

   * set by the safeguard rule inside lstat_cache()

   */

}

#define FL_DIR      (1 << 0)

#define FL_NOENT    (1 << 1)

#define FL_SYMLINK  (1 << 2)

#define FL_LSTATERR (1 << 3)

#define FL_ERR      (1 << 4)

#define FL_FULLPATH (1 << 5)

/*

 * Check if name 'name' of length 'len' has a symlink leading

 * component, or if the directory exists and is real, or not.

 *

 * To speed up the check, some information is allowed to be cached.

 * This can be indicated by the 'track_flags' argument, which also can

 * be used to indicate that we should check the full path.

 *

 * The 'prefix_len_stat_func' parameter can be used to set the length

 * of the prefix, where the cache should use the stat() function

 * instead of the lstat() function to test each path component.

 */

static int lstat_cache_matchlen(struct cache_def *cache,

        const char *name, int len,

        unsigned int *ret_flags, unsigned int track_flags,

        int prefix_len_stat_func)

{

  int match_len, last_slash, last_slash_dir, previous_slash;

  unsigned int save_flags;

  int ret, saved_errno = 0;

  struct stat st;

  if (cache->track_flags != track_flags ||

      cache->prefix_len_stat_func != prefix_len_stat_func) {

    /*

     * As a safeguard rule we clear the cache if the

     * values of track_flags and/or prefix_len_stat_func

     * does not match with the last supplied values.

     */

    reset_lstat_cache(cache);

    cache->track_flags = track_flags;

    cache->prefix_len_stat_func = prefix_len_stat_func;

    match_len = last_slash = 0;

  } else {

    /*

     * Check to see if we have a match from the cache for

     * the 2 "excluding" path types.

     */

    match_len = last_slash =

      longest_path_match(name, len, cache->path.buf,

             cache->path.len, &previous_slash);

    *ret_flags = cache->flags & track_flags & (FL_NOENT|FL_SYMLINK);

    if (!(track_flags & FL_FULLPATH) && match_len == len)

      match_len = last_slash = previous_slash;

    if (*ret_flags && match_len == cache->path.len)

      return match_len;

    /*

     * If we now have match_len > 0, we would know that

     * the matched part will always be a directory.

     *

     * Also, if we are tracking directories and 'name' is

     * a substring of the cache on a path component basis,

     * we can return immediately.

     */

    *ret_flags = track_flags & FL_DIR;

    if (*ret_flags && len == match_len)

      return match_len;

  }

  /*

   * Okay, no match from the cache so far, so now we have to

   * check the rest of the path components.

   */

  *ret_flags = FL_DIR;

  last_slash_dir = last_slash;

  if (len > cache->path.len)

    strbuf_grow(&cache->path, len - cache->path.len);

  while (match_len < len) {

    do {

      cache->path.buf[match_len] = name[match_len];

      match_len++;

    } while (match_len < len && name[match_len] != '/');

    if (match_len >= len && !(track_flags & FL_FULLPATH))

      break;

    last_slash = match_len;

    cache->path.buf[last_slash] = '\0';

    if (last_slash <= prefix_len_stat_func)

      ret = stat(cache->path.buf, &st);

    else

      ret = lstat(cache->path.buf, &st);

    if (ret) {

      *ret_flags = FL_LSTATERR;

      saved_errno = errno;

      if (errno == ENOENT)

        *ret_flags |= FL_NOENT;

    } else if (S_ISDIR(st.st_mode)) {

      last_slash_dir = last_slash;

      continue;

    } else if (S_ISLNK(st.st_mode)) {

      *ret_flags = FL_SYMLINK;

    } else {

      *ret_flags = FL_ERR;

    }

    break;

  }

  /*

   * At the end update the cache.  Note that max 3 different

   * path types, FL_NOENT, FL_SYMLINK and FL_DIR, can be cached

   * for the moment!

   */

  save_flags = *ret_flags & track_flags & (FL_NOENT|FL_SYMLINK);

  if (save_flags && last_slash > 0) {

    cache->path.buf[last_slash] = '\0';

    cache->path.len = last_slash;

    cache->flags = save_flags;

  } else if ((track_flags & FL_DIR) && last_slash_dir > 0) {

    /*

     * We have a separate test for the directory case,

     * since it could be that we have found a symlink or a

     * non-existing directory and the track_flags says

     * that we cannot cache this fact, so the cache would

     * then have been left empty in this case.

     *

     * But if we are allowed to track real directories, we

     * can still cache the path components before the last

     * one (the found symlink or non-existing component).

     */

    cache->path.buf[last_slash_dir] = '\0';

    cache->path.len = last_slash_dir;

    cache->flags = FL_DIR;

  } else {

    reset_lstat_cache(cache);

  }

  if (saved_errno)

    errno = saved_errno;

  return match_len;

}

static unsigned int lstat_cache(struct cache_def *cache, const char *name, int len,

           unsigned int track_flags, int prefix_len_stat_func)

{

  unsigned int flags;

  (void)lstat_cache_matchlen(cache, name, len, &flags, track_flags,

      prefix_len_stat_func);

  return flags;

}

#define USE_ONLY_LSTAT  0

/*

 * Return non-zero if path 'name' has a leading symlink component

 */

int threaded_has_symlink_leading_path(struct cache_def *cache, const char *name, int len)

{

  return lstat_cache(cache, name, len, FL_SYMLINK|FL_DIR, USE_ONLY_LSTAT) & FL_SYMLINK;

}

int has_symlink_leading_path(const char *name, int len)

{

  return threaded_has_symlink_leading_path(&default_cache, name, len);

}

int check_leading_path(const char *name, int len, int warn_on_lstat_err)

{

  return threaded_check_leading_path(&default_cache, name, len,

             warn_on_lstat_err);

}

/*

 * Return zero if some leading path component of 'name' does not exist.

 *

 * Return -1 if leading path exists and is a directory.

 *

 * Return the length of a leading component if it either exists but it's not a

 * directory, or if we were unable to lstat() it. If warn_on_lstat_err is true,

 * also emit a warning for this error.

 */

static int threaded_check_leading_path(struct cache_def *cache, const char *name,

               int len, int warn_on_lstat_err)

{

  unsigned int flags;

  int match_len = lstat_cache_matchlen(cache, name, len, &flags,

         FL_SYMLINK|FL_NOENT|FL_DIR, USE_ONLY_LSTAT);

  int saved_errno = errno;

  if (flags & FL_NOENT)

    return 0;

  else if (flags & FL_DIR)

    return -1;

  if (warn_on_lstat_err && (flags & FL_LSTATERR)) {

    char *path = xmemdupz(name, match_len);

    errno = saved_errno;

    warning_errno(_("failed to lstat '%s'"), path);

    free(path);

  }

  return match_len;

}

int has_dirs_only_path(const char *name, int len, int prefix_len)

{

  return threaded_has_dirs_only_path(&default_cache, name, len, prefix_len);

}

/*

 * Return non-zero if all path components of 'name' exists as a

 * directory.  If prefix_len > 0, we will test with the stat()

 * function instead of the lstat() function for a prefix length of

 * 'prefix_len', thus we then allow for symlinks in the prefix part as

 * long as those points to real existing directories.

 */

static int threaded_has_dirs_only_path(struct cache_def *cache, const char *name, int len, int prefix_len)

{

  /*

   * Note: this function is used by the checkout machinery, which also

   * takes care to properly reset the cache when it performs an operation

   * that would leave the cache outdated. If this function starts caching

   * anything else besides FL_DIR, remember to also invalidate the cache

   * when creating or deleting paths that might be in the cache.

   */

  return lstat_cache(cache, name, len,

         FL_DIR|FL_FULLPATH, prefix_len) &

    FL_DIR;

}

static struct strbuf removal = STRBUF_INIT;

static void do_remove_scheduled_dirs(int new_len)

{

  while (removal.len > new_len) {

    removal.buf[removal.len] = '\0';

    if ((startup_info->original_cwd &&

         !strcmp(removal.buf, startup_info->original_cwd)) ||

        rmdir(removal.buf))

      break;

    do {

      removal.len--;

    } while (removal.len > new_len &&

       removal.buf[removal.len] != '/');

  }

  removal.len = new_len;

}

void schedule_dir_for_removal(const char *name, int len)

{

  int match_len, last_slash, i, previous_slash;

  if (startup_info->original_cwd &&

      !strcmp(name, startup_info->original_cwd))

    return; /* Do not remove the current working directory */

  match_len = last_slash = i =

    longest_path_match(name, len, removal.buf, removal.len,

           &previous_slash);

  /* Find last slash inside 'name' */

  while (i < len) {

    if (name[i] == '/')

      last_slash = i;

    i++;

  }

  /*

   * If we are about to go down the directory tree, we check if

   * we must first go upwards the tree, such that we then can

   * remove possible empty directories as we go upwards.

   */

  if (match_len < last_slash && match_len < removal.len)

    do_remove_scheduled_dirs(match_len);

  /*

   * If we go deeper down the directory tree, we only need to

   * save the new path components as we go down.

   */

  if (match_len < last_slash)

    strbuf_add(&removal, &name[match_len], last_slash - match_len);

}

void remove_scheduled_dirs(void)

{

  do_remove_scheduled_dirs(0);

}

void invalidate_lstat_cache(void)

{

  reset_lstat_cache(&default_cache);

}

#undef rmdir

int lstat_cache_aware_rmdir(const char *path)

{

  /* Any change in this function must be made also in `mingw_rmdir()` */

  int ret = rmdir(path);

  if (!ret)

    invalidate_lstat_cache();

  return ret;

}