soup-cache: Add versioning support to SoupCache

Cache index file was renamed to soup.cache2. It now contains the version of
the cache used to store data. If the version used to save the file is not
the same than the current cache versions then cache files will be deleted.

https://bugzilla.gnome.org/show_bug.cgi?id=652554

diff --git a/libsoup/soup-cache.c b/libsoup/soup-cache.c
index d5a845f..b430610 100644 (file)
--- a/libsoup/soup-cache.c
+++ b/libsoup/soup-cache.c
@@ -52,6 +52,12 @@ static void soup_cache_session_feature_init (SoupSessionFeatureInterface *featur
                                        of the cache that can be
                                        filled by a single entry */
 
+/*
+ * Version 2: cache is now saved in soup.cache2. Added the version
+ * number to the beginning of the file.
+ */
+#define SOUP_CACHE_CURRENT_VERSION 2
+
 typedef struct _SoupCacheEntry {
        char *key;
        char *filename;
@@ -1537,11 +1543,12 @@ soup_cache_generate_conditional_request (SoupCache *cache, SoupMessage *original
        return msg;
 }
 
-#define SOUP_CACHE_FILE "soup.cache"
+#define OLD_SOUP_CACHE_FILE "soup.cache"
+#define SOUP_CACHE_FILE "soup.cache2"
 
 #define SOUP_CACHE_HEADERS_FORMAT "{ss}"
 #define SOUP_CACHE_PHEADERS_FORMAT "(ssbuuuuua" SOUP_CACHE_HEADERS_FORMAT ")"
-#define SOUP_CACHE_ENTRIES_FORMAT "a" SOUP_CACHE_PHEADERS_FORMAT
+#define SOUP_CACHE_ENTRIES_FORMAT "(ua" SOUP_CACHE_PHEADERS_FORMAT ")"
 
 /* Basically the same format than above except that some strings are
    prepended with &. This way the GVariant returns a pointer to the
@@ -1596,7 +1603,10 @@ soup_cache_dump (SoupCache *cache)
 
        /* Create the builder and iterate over all entries */
        g_variant_builder_init (&entries_builder, G_VARIANT_TYPE (SOUP_CACHE_ENTRIES_FORMAT));
+       g_variant_builder_add (&entries_builder, "u", SOUP_CACHE_CURRENT_VERSION);
+       g_variant_builder_open (&entries_builder, G_VARIANT_TYPE ("a" SOUP_CACHE_PHEADERS_FORMAT));
        g_list_foreach (cache->priv->lru_start, pack_entry, &entries_builder);
+       g_variant_builder_close (&entries_builder);
 
        /* Serialize and dump */
        cache_variant = g_variant_builder_end (&entries_builder);
@@ -1608,6 +1618,30 @@ soup_cache_dump (SoupCache *cache)
        g_variant_unref (cache_variant);
 }
 
+static void
+clear_cache_files (SoupCache *cache)
+{
+       GFileInfo *file_info;
+       GFileEnumerator *file_enumerator;
+       GFile *cache_dir_file = g_file_new_for_path (cache->priv->cache_dir);
+
+       file_enumerator = g_file_enumerate_children (cache_dir_file, G_FILE_ATTRIBUTE_STANDARD_NAME,
+                                                    G_FILE_QUERY_INFO_NONE, NULL, NULL);
+       if (file_enumerator) {
+               while ((file_info = g_file_enumerator_next_file (file_enumerator, NULL, NULL)) != NULL) {
+                       const gchar *filename = g_file_info_get_name (file_info);
+
+                       if (strcmp (filename, SOUP_CACHE_FILE) != 0) {
+                               GFile *cache_file = g_file_get_child (cache_dir_file, filename);
+                               g_file_delete (cache_file, NULL, NULL);
+                               g_object_unref (cache_file);
+                       }
+               }
+               g_object_unref (file_enumerator);
+       }
+       g_object_unref (cache_dir_file);
+}
+
 void
 soup_cache_load (SoupCache *cache)
 {
@@ -1616,24 +1650,34 @@ soup_cache_load (SoupCache *cache)
        time_t corrected_initial_age, response_time;
        char *key, *filename = NULL, *contents = NULL;
        GVariant *cache_variant;
-       GVariantIter entries_iter, *headers_iter = NULL;
+       GVariantIter *entries_iter = NULL, *headers_iter = NULL;
        gsize length, items;
        SoupCacheEntry *entry;
        SoupCachePrivate *priv = cache->priv;
+       guint version;
 
        filename = g_build_filename (priv->cache_dir, SOUP_CACHE_FILE, NULL);
        if (!g_file_get_contents (filename, &contents, &length, NULL)) {
                g_free (filename);
                g_free (contents);
+               clear_cache_files (cache);
                return;
        }
        g_free (filename);
 
        cache_variant = g_variant_new_from_data (G_VARIANT_TYPE (SOUP_CACHE_ENTRIES_FORMAT),
                                                 (const gchar *) contents, length, FALSE, g_free, contents);
-       items = g_variant_iter_init (&entries_iter, cache_variant);
+       g_variant_get (cache_variant, SOUP_CACHE_ENTRIES_FORMAT, &version, &entries_iter);
+       if (version != SOUP_CACHE_CURRENT_VERSION) {
+               g_variant_iter_free (entries_iter);
+               g_variant_unref (cache_variant);
+               clear_cache_files (cache);
+               return;
+       }
+
+       items = g_variant_iter_n_children (entries_iter);
 
-       while (g_variant_iter_loop (&entries_iter, SOUP_CACHE_PHEADERS_FORMAT,
+       while (g_variant_iter_loop (entries_iter, SOUP_CACHE_PHEADERS_FORMAT,
                                    &key, &filename, &must_revalidate,
                                    &freshness_lifetime, &corrected_initial_age,
                                    &response_time, &hits, &length,