AppCache: Add a helper method to AppCacheService to test if a request can be handled while offline.

BUG=65547, chromium-os:9559
TEST=none

Review URL: http://codereview.chromium.org/6269016

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@72433 0039d316-1c4b-4281-b951-d872f2087c98

webkit/appcache/appcache_service.cc

@@ -8,6 +8,7 @@
 #include "base/message_loop.h"
 #include "base/stl_util-inl.h"
 #include "webkit/appcache/appcache_backend_impl.h"
+#include "webkit/appcache/appcache_entry.h"
 #include "webkit/appcache/appcache_storage_impl.h"
 
 namespace appcache {
@@ -60,6 +61,43 @@ void AppCacheService::AsyncHelper::Cancel() {
   service_ = NULL;
 }
 
+// CanHandleOfflineHelper -------
+
+class AppCacheService::CanHandleOfflineHelper : AsyncHelper {
+ public:
+  CanHandleOfflineHelper(
+      AppCacheService* service, const GURL& url,
+      net::CompletionCallback* callback)
+      : AsyncHelper(service, callback), url_(url) {
+  }
+
+  virtual void Start() {
+    service_->storage()->FindResponseForMainRequest(url_, this);
+  }
+
+ private:
+  // AppCacheStorage::Delegate override
+  virtual void OnMainResponseFound(
+      const GURL& url, const AppCacheEntry& entry,
+      const GURL& fallback_url, const AppCacheEntry& fallback_entry,
+      int64 cache_id, const GURL& mainfest_url,
+      bool was_blocked_by_policy);
+
+  GURL url_;
+  DISALLOW_COPY_AND_ASSIGN(CanHandleOfflineHelper);
+};
+
+void AppCacheService::CanHandleOfflineHelper::OnMainResponseFound(
+      const GURL& url, const AppCacheEntry& entry,
+      const GURL& fallback_url, const AppCacheEntry& fallback_entry,
+      int64 cache_id, const GURL& mainfest_url,
+      bool was_blocked_by_policy) {
+  bool can = !was_blocked_by_policy &&
+             (entry.has_response_id() || fallback_entry.has_response_id());
+  CallCallback(can ? net::OK : net::ERR_FAILED);
+  delete this;
+}
+
 // DeleteHelper -------
 
 class AppCacheService::DeleteHelper : public AsyncHelper {
@@ -82,6 +120,7 @@ class AppCacheService::DeleteHelper : public AsyncHelper {
       appcache::AppCacheGroup* group, bool success);
 
   GURL manifest_url_;
+  DISALLOW_COPY_AND_ASSIGN(DeleteHelper);
 };
 
 void AppCacheService::DeleteHelper::OnGroupLoaded(
@@ -121,6 +160,7 @@ class AppCacheService::GetInfoHelper : AsyncHelper {
   virtual void OnAllInfo(AppCacheInfoCollection* collection);
 
   scoped_refptr<AppCacheInfoCollection> collection_;
+  DISALLOW_COPY_AND_ASSIGN(GetInfoHelper);
 };
 
 void AppCacheService::GetInfoHelper::OnAllInfo(
@@ -155,6 +195,14 @@ void AppCacheService::Initialize(const FilePath& cache_directory,
   storage_.reset(storage);
 }
 
+void AppCacheService::CanHandleMainResourceOffline(
+    const GURL& url,
+    net::CompletionCallback* callback) {
+  CanHandleOfflineHelper* helper =
+      new CanHandleOfflineHelper(this, url, callback);
+  helper->Start();
+}
+
 void AppCacheService::GetAllAppCacheInfo(AppCacheInfoCollection* collection,
                                          net::CompletionCallback* callback) {
   DCHECK(collection);

webkit/appcache/appcache_service.h

@@ -58,6 +58,11 @@ class AppCacheService {
       storage_->PurgeMemory();
   }
 
+  // Determines if a request for 'url' can be satisfied while offline.
+  // This method always completes asynchronously.
+  void CanHandleMainResourceOffline(const GURL& url,
+                                    net::CompletionCallback* callback);
+
   // Populates 'collection' with info about all of the appcaches stored
   // within the service, 'callback' is invoked upon completion. The service
   // acquires a reference to the 'collection' until until completion.
@@ -103,6 +108,7 @@ class AppCacheService {
 
  protected:
   class AsyncHelper;
+  class CanHandleOfflineHelper;
   class DeleteHelper;
   class GetInfoHelper;