util/disk_cache: Delete the old multifile cache if using the default.

Only after 7 days so people who switch all the time aren't impacted.

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/22339>

src/util/disk_cache.c

@@ -273,8 +273,14 @@ disk_cache_create(const char *gpu_name, const char *driver_id,
       cache_type = DISK_CACHE_SINGLE_FILE;
    else if (debug_get_bool_option("MESA_DISK_CACHE_MULTI_FILE", false))
       cache_type = DISK_CACHE_MULTI_FILE;
-   else
+   else {
       cache_type = DISK_CACHE_DATABASE;
+      /* Since switching the default cache to <mesa_shader_cache_db>, remove the
+       * old cache folder if it hasn't been modified for more than 7 days.
+       */
+      if (!getenv("MESA_SHADER_CACHE_DIR") && !getenv("MESA_GLSL_CACHE_DIR"))
+         disk_cache_delete_old_cache();
+   }
 
    /* Create main writable cache. */
    cache = disk_cache_type_create(gpu_name, driver_id, driver_flags,

src/util/disk_cache_os.c

@@ -1198,6 +1198,68 @@ disk_cache_db_load_cache_index(void *mem_ctx, struct disk_cache *cache)
 {
    return mesa_cache_db_multipart_open(&cache->cache_db, cache->path);
 }
+
+static void
+delete_dir(const char* path)
+{
+   DIR *dir = opendir(path);
+   if (!dir)
+      return;
+
+   struct dirent *p;
+   char *entry_path = NULL;
+
+   while ((p = readdir(dir)) != NULL) {
+      if (strcmp(p->d_name, ".") == 0 || strcmp(p->d_name, "..") == 0)
+         continue;
+
+      asprintf(&entry_path, "%s/%s", path, p->d_name);
+      if (!entry_path)
+         continue;
+
+      struct stat st;
+      if (stat(entry_path, &st)) {
+         free(entry_path);
+         continue;
+      }
+      if (S_ISDIR(st.st_mode))
+         delete_dir(entry_path);
+      else
+         unlink(entry_path);
+
+      free(entry_path);
+   }
+   closedir(dir);
+   rmdir(path);
+}
+
+/* Deletes old multi-file caches, to avoid having two default caches taking up disk space. */
+void
+disk_cache_delete_old_cache(void)
+{
+   void *ctx = ralloc_context(NULL);
+   char *dirname = disk_cache_generate_cache_dir(ctx, NULL, NULL, DISK_CACHE_MULTI_FILE);
+   if (!dirname)
+      goto finish;
+
+   /* The directory itself doesn't get updated, so use a marker timestamp */
+   char *index_path = ralloc_asprintf(ctx, "%s/marker", dirname);
+
+   struct stat attr;
+   if (stat(index_path, &attr) == -1)
+      goto finish;
+
+   time_t now = time(NULL);
+
+   /* Do not delete anything if the cache has been modified in the past week */
+   if (now - attr.st_mtime < 60 * 60 * 24 * 7)
+      goto finish;
+
+   delete_dir(dirname);
+
+finish:
+   ralloc_free(ctx);
+}
 #endif
 
 #endif /* ENABLE_SHADER_CACHE */

src/util/disk_cache_os.h

@@ -181,6 +181,9 @@ disk_cache_db_write_item_to_disk(struct disk_cache_put_job *dc_job);
 bool
 disk_cache_db_load_cache_index(void *mem_ctx, struct disk_cache *cache);
 
+void
+disk_cache_delete_old_cache(void);
+
 #ifdef __cplusplus
 }
 #endif