path: use XDG cache and XDG data dirs by default

Currently, mpv stores some non-config data in ~/.config by default. For
users that back up their dotconfigs, this can be annoying. This reworks
the path logic to make use of the XDG_CACHE_HOME and XDG_DATA_HOME
environment variables with the appropriate fallbacks if they don't
exist.

mpv's watch_later directory is now stored in the data directory
(~/.local/share/mpv for most users). This part of the change only
affects *nix users. Other platforms will still use the config directory
since the XDG paradigm doesn't exist there. In a separate but related
change, the --cache-dir options defaults to the cache directory
(~/.cache/mpv for most users). The change in where to store cache does
affect all platforms. For those that aren't on *nix systems, the default
cache directory is the same as their config directory.

Both of these new directories are only used if the user is using
XDG_CONFIG_HOME (or the default ~/.config/mpv fallback). If the user is
using the old compatibility path (~/.mpv) or has forced a config
directory (either using the --configdir option or the MPV_HOME
environment variable), then everything is stored in the config directory
like before and there is no splitting of data.

Internally, this change modifies the mp_find_user_config_file and
mp_mk_config_dir functions to make them slightly more generic (now named
mp_find_user_file and mp_mk_user_dir respectively).

DOCS/interface-changes.rst

@@ -29,6 +29,9 @@ Interface changes
  --- mpv 0.34.0 ---
     - add `--screen-name` and `--fs-screen-name` flags to allow selecting the 
       screen by its name instead of the index
+    - the watch_later directory is now stored in "~/.local/share/mpv" by default (unix)
+    - the cache-dir option defaults to "~/.cache/mpv" instead of none (unix). For
+      other platforms/configurations, the cache is stored in mpv's config directory.
  --- mpv 0.33.0 ---
     - add `--d3d11-exclusive-fs` flag to enable D3D11 exclusive fullscreen mode
       when the player enters fullscreen.

DOCS/man/mpv.rst

@@ -1561,7 +1561,7 @@ For Windows-specifics, see `FILES ON WINDOWS`_ section.
 
     See `Script location`_ for details.
 
-``~/.config/mpv/watch_later/``
+``~/.local/share/mpv/watch_later/``
     Contains temporary config files needed for resuming playback of files with
     the watch later feature. See for example the ``Q`` key binding, or the
     ``quit-watch-later`` input command.

DOCS/man/options.rst

@@ -754,7 +754,7 @@ Program Behavior
     The directory in which to store the "watch later" temporary files.
 
     The default is a subdirectory named "watch_later" underneath the
-    config directory (usually ``~/.config/mpv/``).
+    local data directory (usually ``~/.local/share/mpv/``).
 
 ``--dump-stats=<filename>``
     Write certain statistics to the given file. The file is truncated on
@@ -4585,8 +4585,6 @@ Cache
     This makes sense only with ``--cache``. If the normal cache is disabled,
     this option is ignored.
 
-    You need to set ``--cache-dir`` to use this.
-
     The cache file is append-only. Even if the player appears to prune data, the
     file space freed by it is not reused. The cache file is deleted when
     playback is closed.
@@ -4609,7 +4607,7 @@ Cache
     continue to use the cache file that was opened first.
 
 ``--cache-dir=<path>``
-    Directory where to create temporary files (default: none).
+    Directory where to create temporary files (usually ``~/.cache/mpv``).
 
     Currently, this is used for ``--cache-on-disk`` only.
 

demux/cache.c

@@ -100,10 +100,11 @@ struct demux_cache *demux_cache_create(struct mpv_global *global,
     cache->fd = -1;
 
     char *cache_dir = cache->opts->cache_dir;
-    if (!(cache_dir && cache_dir[0])) {
-        MP_ERR(cache, "No cache data directory supplied.\n");
-        goto fail;
-    }
+    if (!(cache_dir && cache_dir[0]))
+        cache_dir = mp_find_user_file(NULL, global, "cache", "");
+
+    if (!mp_path_exists(cache_dir))
+        mp_mk_user_dir(global, "cache", cache_dir);
 
     cache->filename = mp_path_join(cache, cache_dir, "mpv-cache-XXXXXX.dat");
     cache->fd = mp_mkostemps(cache->filename, 4, O_CLOEXEC);

options/path.c

@@ -100,15 +100,21 @@ static const char *mp_get_platform_path(void *talloc_ctx,
     return NULL;
 }
 
-char *mp_find_user_config_file(void *talloc_ctx, struct mpv_global *global,
-                               const char *filename)
+char *mp_find_user_file(void *talloc_ctx, struct mpv_global *global,
+                        const char *type, const char *filename)
 {
     void *tmp = talloc_new(NULL);
-    char *res = (char *)mp_get_platform_path(tmp, global, config_dirs[0]);
+    char *res;
+    /* If the user forces a configdir, always return this path. */
+    if (global->configdir) {
+        res = (char *)mp_get_platform_path(tmp, global, config_dirs[0]);
+    } else {
+        res = (char *)mp_get_platform_path(tmp, global, type);
+    }
     if (res)
         res = mp_path_join(talloc_ctx, res, filename);
     talloc_free(tmp);
-    MP_DBG(global, "config path: '%s' -> '%s'\n", filename, res ? res : "-");
+    MP_DBG(global, "path: '%s' -> '%s'\n", filename, res ? res : "-");
     return res;
 }
 
@@ -376,9 +382,9 @@ void mp_mkdirp(const char *dir)
     talloc_free(path);
 }
 
-void mp_mk_config_dir(struct mpv_global *global, char *subdir)
+void mp_mk_user_dir(struct mpv_global *global, const char *type, char *subdir)
 {
-    char *dir = mp_find_user_config_file(NULL, global, subdir);
+    char *dir = mp_find_user_file(NULL, global, type, subdir);
     if (dir)
         mp_mkdirp(dir);
     talloc_free(dir);

options/path.h

@@ -34,11 +34,11 @@ void mp_init_paths(struct mpv_global *global, struct MPOpts *opts);
 char *mp_find_config_file(void *talloc_ctx, struct mpv_global *global,
                           const char *filename);
 
-// Like mp_find_config_file(), but search only the local writable user config
-// dir. Also, this returns a result even if the file does not exist. Calling
-// it with filename="" is equivalent to retrieving the user config dir.
-char *mp_find_user_config_file(void *talloc_ctx, struct mpv_global *global,
-                               const char *filename);
+// Search for local writable user files (config, data, or cache). This returns
+// a result even if the file does not exist. Calling it with filename="" is
+// equivalent to retrieving the user config dir.
+char *mp_find_user_file(void *talloc_ctx, struct mpv_global *global,
+                        const char *type, const char *filename);
 
 // Find all instances of the given config file. Paths are returned in order
 // from lowest to highest priority. filename can contain multiple names
@@ -90,6 +90,6 @@ bool mp_is_url(bstr path);
 bstr mp_split_proto(bstr path, bstr *out_url);
 
 void mp_mkdirp(const char *dir);
-void mp_mk_config_dir(struct mpv_global *global, char *subdir);
+void mp_mk_user_dir(struct mpv_global *global, const char *type, char *subdir);
 
 #endif /* MPLAYER_PATH_H */

osdep/path-unix.c

@@ -27,11 +27,15 @@ static pthread_once_t path_init_once = PTHREAD_ONCE_INIT;
 
 static char mpv_home[512];
 static char old_home[512];
+static char mpv_cache[512];
+static char mpv_data[512];
 
 static void path_init(void)
 {
     char *home = getenv("HOME");
     char *xdg_dir = getenv("XDG_CONFIG_HOME");
+    char *xdg_cache = getenv("XDG_CACHE_HOME");
+    char *xdg_data = getenv("XDG_DATA_HOME");
 
     if (xdg_dir && xdg_dir[0]) {
         snprintf(mpv_home, sizeof(mpv_home), "%s/mpv", xdg_dir);
@@ -43,10 +47,24 @@ static void path_init(void)
     if (home && home[0])
         snprintf(old_home, sizeof(old_home), "%s/.mpv", home);
 
+    if (xdg_cache && xdg_cache[0]) {
+        snprintf(mpv_cache, sizeof(mpv_cache), "%s/mpv", xdg_cache);
+    } else if (home && home[0]) {
+        snprintf(mpv_cache, sizeof(mpv_cache), "%s/.cache/mpv", home);
+    }
+
+    if (xdg_data && xdg_data[0]) {
+        snprintf(mpv_data, sizeof(mpv_data), "%s/mpv", xdg_data);
+    } else if (home && home[0]) {
+        snprintf(mpv_data, sizeof(mpv_data), "%s/.local/share/mpv", home);
+    }
+
     // If the old ~/.mpv exists, and the XDG config dir doesn't, use the old
-    // config dir only.
+    // config dir only. Also do not use XDG cache or XDG data directories.
     if (mp_path_exists(old_home) && !mp_path_exists(mpv_home)) {
         snprintf(mpv_home, sizeof(mpv_home), "%s", old_home);
+        snprintf(mpv_cache, sizeof(mpv_cache), "%s", old_home);
+        snprintf(mpv_data, sizeof(mpv_data), "%s", old_home);
         old_home[0] = '\0';
     }
 }
@@ -58,6 +76,10 @@ const char *mp_get_platform_path_unix(void *talloc_ctx, const char *type)
         return mpv_home;
     if (strcmp(type, "old_home") == 0)
         return old_home;
+    if (strcmp(type, "cache") == 0)
+        return mpv_cache;
+    if (strcmp(type, "data") == 0)
+        return mpv_data;
     if (strcmp(type, "global") == 0)
         return MPV_CONFDIR;
     if (strcmp(type, "desktop") == 0)

osdep/path-uwp.c

@@ -26,7 +26,9 @@ WINBASEAPI DWORD WINAPI GetCurrentDirectoryW(DWORD nBufferLength, LPWSTR lpBuffe
 
 const char *mp_get_platform_path_uwp(void *talloc_ctx, const char *type)
 {
-    if (strcmp(type, "home") == 0) {
+    if (strcmp(type, "home") == 0 || strcmp(type, "cache") == 0 ||
+        strcmp(type, "data") == 0)
+    {
         wchar_t homeDir[_MAX_PATH];
         if (GetCurrentDirectoryW(_MAX_PATH, homeDir) != 0)
             return mp_to_utf8(talloc_ctx, homeDir);

osdep/path-win.c

@@ -85,10 +85,15 @@ const char *mp_get_platform_path_win(void *talloc_ctx, const char *type)
 {
     pthread_once(&path_init_once, path_init);
     if (portable_path) {
-        if (strcmp(type, "home") == 0)
+        if (strcmp(type, "home") == 0 || strcmp(type, "cache") == 0 ||
+            strcmp(type, "data") == 0)
+        {
             return portable_path;
+        }
     } else {
-        if (strcmp(type, "home") == 0)
+        if (strcmp(type, "home") == 0 || strmcp(type, "cache") == 0 ||
+            strcmp(type, "data") == 0)
+        {
             return mp_get_win_app_dir(talloc_ctx);
         if (strcmp(type, "exe_dir") == 0)
             return mp_get_win_exe_dir(talloc_ctx);

osdep/path.h

@@ -11,6 +11,13 @@
 //  "global"        the least priority, global config file location
 //  "desktop"       path to desktop contents
 //
+//  These additional type values are also defined. It is only used if
+//  the native mpv-specific user config dir is defined and only has any
+//  special meaning on unix platforms (elsewhere, the user config dir is
+//  returned).
+//  "cache"         path to local user cache files
+//  "data"          path to local user data files
+//
 // It is allowed to return a static string, so the caller must set talloc_ctx
 // to something other than NULL to avoid memory leaks.
 typedef const char *(*mp_get_platform_path_cb)(void *talloc_ctx, const char *type);

player/configfiles.c

@@ -63,7 +63,7 @@ void mp_parse_cfgfiles(struct MPContext *mpctx)
 {
     struct MPOpts *opts = mpctx->opts;
 
-    mp_mk_config_dir(mpctx->global, "");
+    mp_mk_user_dir(mpctx->global, "home", "");
 
     char *p1 = mp_get_user_path(NULL, mpctx->global, "~~home/");
     char *p2 = mp_get_user_path(NULL, mpctx->global, "~~old_home/");
@@ -226,7 +226,7 @@ static char *mp_get_playback_resume_config_filename(struct MPContext *mpctx,
 
     if (!mpctx->cached_watch_later_configdir) {
         mpctx->cached_watch_later_configdir =
-            mp_find_user_config_file(mpctx, mpctx->global, MP_WATCH_LATER_CONF);
+            mp_find_user_file(mpctx, mpctx->global, "data", MP_WATCH_LATER_CONF);
     }
 
     if (mpctx->cached_watch_later_configdir)
@@ -349,7 +349,7 @@ void mp_write_watch_later_conf(struct MPContext *mpctx)
     if (!conffile)
         goto exit;
 
-    mp_mk_config_dir(mpctx->global, mpctx->cached_watch_later_configdir);
+    mp_mk_user_dir(mpctx->global, "data", mpctx->cached_watch_later_configdir);
 
     MP_INFO(mpctx, "Saving state.\n");