[libsoup] soup-cache: Add versioning support to SoupCache

[Sergio Villar Senin <svillar src gnome org>]

commit a85f923f5096b3918a4274af96d18a5fe05224f7
Author: Sergio Villar Senin <svillar igalia com>
Date:   Tue Jun 14 13:37:05 2011 +0200

    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

 libsoup/soup-cache.c |   54 +++++++++++++++++++++++++++++++++++++++++++++----
 1 files changed, 49 insertions(+), 5 deletions(-)
---
diff --git a/libsoup/soup-cache.c b/libsoup/soup-cache.c
index d5a845f..b430610 100644
--- 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,