Implement cancelling an appcache update. An update is cancelled when its application cache group is no longer in use. Refcounting of caches and groups changed to make cancelling an update work.

TEST=updated existing tests, verify deleting group cancels update, verify new refcounting behavior
BUG=none


Review URL: http://codereview.chromium.org/274013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@29291 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 21 insertions, 5 deletions

diff --git a/webkit/appcache/appcache_host.h b/webkit/appcache/appcache_host.h
index 5be3c5c..1ebb68b 100644
--- a/webkit/appcache/appcache_host.h
+++ b/webkit/appcache/appcache_host.h
@@ -11,6 +11,7 @@
 #include "googleurl/src/gurl.h"
 #include "testing/gtest/include/gtest/gtest_prod.h"
 #include "webkit/appcache/appcache.h"
+#include "webkit/appcache/appcache_group.h"
 #include "webkit/appcache/appcache_interfaces.h"
 #include "webkit/appcache/appcache_service.h"
 #include "webkit/appcache/appcache_storage.h"
@@ -21,7 +22,6 @@ namespace appcache {
 
 class AppCache;
 class AppCacheFrontend;
-class AppCacheGroup;
 class AppCacheRequestHandler;
 
 typedef Callback2<Status, void*>::Type GetStatusCallback;
@@ -29,7 +29,8 @@ typedef Callback2<bool, void*>::Type StartUpdateCallback;
 typedef Callback2<bool, void*>::Type SwapCacheCallback;
 
 // Server-side representation of an application cache host.
-class AppCacheHost : public AppCacheStorage::Delegate {
+class AppCacheHost : public AppCacheStorage::Delegate,
+                     public AppCacheGroup::UpdateObserver {
  public:
 
   class Observer {
@@ -76,6 +77,10 @@ class AppCacheHost : public AppCacheStorage::Delegate {
   // or by the update algorithm (see AppCacheUpdateJob).
   void AssociateCache(AppCache* cache);
 
+  // Adds a reference to the newest complete cache in a group, unless it's the
+  // same as the cache that is currently associated with the host.
+  void SetSwappableCache(AppCacheGroup* group);
+
   int host_id() const { return host_id_; }
   AppCacheService* service() const { return service_; }
   AppCacheFrontend* frontend() const { return frontend_; }
@@ -100,15 +105,25 @@ class AppCacheHost : public AppCacheStorage::Delegate {
   void DoPendingStartUpdate();
   void DoPendingSwapCache();
 
+  void ObserveGroupBeingUpdated(AppCacheGroup* group);
+
+  // AppCacheGroup::UpdateObserver method
+  virtual void OnUpdateComplete(AppCacheGroup* group);
+
   // Identifies the corresponding appcache host in the child process.
   int host_id_;
 
   // The cache associated with this host, if any.
   scoped_refptr<AppCache> associated_cache_;
 
-  // The reference to the group ensures the group exists
-  // while we have an association with a cache in the group.
-  scoped_refptr<AppCacheGroup> group_;
+  // Hold a reference to the newest complete cache (if associated cache is
+  // not the newest) to keep the newest cache in existence while the app cache
+  // group is in use. The newest complete cache may have no associated hosts
+  // holding any references to it and would otherwise be deleted prematurely.
+  scoped_refptr<AppCache> swappable_cache_;
+
+  // Keep a reference to the group being updated until the update completes.
+  scoped_refptr<AppCacheGroup> group_being_updated_;
 
   // Cache loading is async, if we're loading a specific cache or group
   // for the purposes of cache selection, one or the other of these will
@@ -145,6 +160,7 @@ class AppCacheHost : public AppCacheStorage::Delegate {
   FRIEND_TEST(AppCacheHostTest, ForeignEntry);
   FRIEND_TEST(AppCacheHostTest, FailedCacheLoad);
   FRIEND_TEST(AppCacheHostTest, FailedGroupLoad);
+  FRIEND_TEST(AppCacheHostTest, SetSwappableCache);
   DISALLOW_COPY_AND_ASSIGN(AppCacheHost);
 };