base::Bind: Implement a 1-arity CancelableCallback and use this to implement

webkit/appcache/appcache_service.cc

 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "webkit/appcache/appcache_service.h"
 
 #include "base/bind.h"
 #include "base/logging.h"
 #include "base/message_loop.h"
 #include "base/stl_util.h"
@@ skipping 10 matching lines @@
 #include "webkit/quota/special_storage_policy.h"
 
 namespace appcache {
 
 AppCacheInfoCollection::AppCacheInfoCollection() {}
 
 AppCacheInfoCollection::~AppCacheInfoCollection() {}
 
 // AsyncHelper -------
 
+class AppCacheService::NewAsyncHelper
+    : public AppCacheStorage::Delegate {
+ public:
+  NewAsyncHelper(AppCacheService* service,
+                 const net::CompletionCallback& callback)
+      : service_(service), callback_(callback) {
+    service_->pending_new_helpers_.insert(this);
+  }
+
+  virtual ~NewAsyncHelper() {
+    if (service_)
+      service_->pending_new_helpers_.erase(this);
+  }
+
+  virtual void Start() = 0;
+  virtual void Cancel();
+
+ protected:
+  void CallCallback(int rv) {
+    if (!callback_.is_null()) {
+      // Defer to guarantee async completion.
+      MessageLoop::current()->PostTask(
+          FROM_HERE, base::Bind(&DeferredCallCallback, callback_, rv));
+    }
+    callback_.Reset();
+  }
+
+  static void DeferredCallCallback(const net::CompletionCallback& callback,
+                                   int rv) {
+    callback.Run(rv);
+  }
+
+  AppCacheService* service_;
+  net::CompletionCallback callback_;
+};
+
+void AppCacheService::NewAsyncHelper::Cancel() {
+  if (!callback_.is_null()) {
+    callback_.Run(net::ERR_ABORTED);
+    callback_.Reset();
+  }
+
+  service_->storage()->CancelDelegateCallbacks(this);
+  service_ = NULL;
+}
+
 class AppCacheService::AsyncHelper
     : public AppCacheStorage::Delegate {
  public:
   AsyncHelper(
       AppCacheService* service, net::OldCompletionCallback* callback)
       : service_(service), callback_(callback) {
     service_->pending_helpers_.insert(this);
   }
 
   virtual ~AsyncHelper() {
@@ skipping 27 matching lines @@
   if (callback_) {
     callback_->Run(net::ERR_ABORTED);
     callback_ = NULL;
   }
   service_->storage()->CancelDelegateCallbacks(this);
   service_ = NULL;
 }
 
 // CanHandleOfflineHelper -------
 
-class AppCacheService::CanHandleOfflineHelper : AsyncHelper {
+class AppCacheService::CanHandleOfflineHelper : NewAsyncHelper {
  public:
   CanHandleOfflineHelper(
       AppCacheService* service, const GURL& url,
-      const GURL& first_party, net::OldCompletionCallback* callback)
-      : AsyncHelper(service, callback), url_(url), first_party_(first_party) {
+      const GURL& first_party, const net::CompletionCallback& callback)
+      : NewAsyncHelper(service, callback),
+        url_(url),
+        first_party_(first_party) {
   }
 
   virtual void Start() {
     AppCachePolicy* policy = service_->appcache_policy();
     if (policy && !policy->CanLoadAppCache(url_, first_party_)) {
       CallCallback(net::ERR_FAILED);
       delete this;
       return;
     }
+
     service_->storage()->FindResponseForMainRequest(url_, GURL(), 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, int64 group_id, const GURL& mainfest_url) OVERRIDE;
 
   GURL url_;
   GURL first_party_;
+
   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, int64 group_id, const GURL& manifest_url) {
   bool can = (entry.has_response_id() || fallback_entry.has_response_id());
   CallCallback(can ? net::OK : net::ERR_FAILED);
   delete this;
@@ skipping 304 matching lines @@
     quota_manager_proxy_->RegisterClient(quota_client_);
   }
 }
 
 AppCacheService::~AppCacheService() {
   DCHECK(backends_.empty());
   std::for_each(pending_helpers_.begin(),
                 pending_helpers_.end(),
                 std::mem_fun(&AsyncHelper::Cancel));
   STLDeleteElements(&pending_helpers_);
+  std::for_each(pending_new_helpers_.begin(),
+                pending_new_helpers_.end(),
+                std::mem_fun(&NewAsyncHelper::Cancel));
+  STLDeleteElements(&pending_new_helpers_);
   if (quota_client_)
     quota_client_->NotifyAppCacheDestroyed();
 
   // Destroy storage_ first; ~AppCacheStorageImpl accesses other data members
   // (special_storage_policy_).
   storage_.reset();
 }
 
 void AppCacheService::Initialize(const FilePath& cache_directory,
                                  base::MessageLoopProxy* db_thread,
                                  base::MessageLoopProxy* cache_thread) {
   DCHECK(!storage_.get());
   AppCacheStorageImpl* storage = new AppCacheStorageImpl(this);
   storage->Initialize(cache_directory, db_thread, cache_thread);
   storage_.reset(storage);
 }
 
 void AppCacheService::CanHandleMainResourceOffline(
     const GURL& url,
     const GURL& first_party,
-    net::OldCompletionCallback* callback) {
+    const net::CompletionCallback& callback) {
   CanHandleOfflineHelper* helper =
       new CanHandleOfflineHelper(this, url, first_party, callback);
   helper->Start();
 }
 
 void AppCacheService::GetAllAppCacheInfo(AppCacheInfoCollection* collection,
                                          net::OldCompletionCallback* callback) {
   DCHECK(collection);
   GetInfoHelper* helper = new GetInfoHelper(this, collection, callback);
   helper->Start();
@@ skipping 30 matching lines @@
   backends_.insert(
       BackendMap::value_type(backend_impl->process_id(), backend_impl));
 }
 
 void AppCacheService::UnregisterBackend(
     AppCacheBackendImpl* backend_impl) {
   backends_.erase(backend_impl->process_id());
 }
 
 }  // namespace appcache