Change threading in ServiceWorkerCacheStorage

content/browser/service_worker/service_worker_cache_storage.h

 // Copyright 2014 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.
 
 #ifndef CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_CACHE_STORAGE_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_CACHE_STORAGE_H_
 
 #include <map>
 #include <string>
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
 #include "base/id_map.h"
-#include "base/threading/thread_checker.h"
+#include "base/memory/weak_ptr.h"
 
 namespace base {
-class MessageLoopProxy;
+class SequencedTaskRunner;
 }
 
 namespace content {
-
 class ServiceWorkerCache;
 
 // TODO(jkarlin): Constrain the total bytes used per origin.
-// The set of caches for a given origin. It is owned by the
-// ServiceWorkerCacheStorageManager. Provided callbacks are called on the
-// |callback_loop| provided in the constructor.
+
+// ServiceWorkerCacheStorage holds the set of caches for a given origin. It is
+// owned by the ServiceWorkerCacheStorageManager. This class expects to be run
+// on the IO thread.
 class ServiceWorkerCacheStorage {
  public:
   enum CacheStorageError {
     CACHE_STORAGE_ERROR_NO_ERROR,
     CACHE_STORAGE_ERROR_NOT_IMPLEMENTED,
     CACHE_STORAGE_ERROR_NOT_FOUND,
     CACHE_STORAGE_ERROR_EXISTS,
     CACHE_STORAGE_ERROR_STORAGE,
     CACHE_STORAGE_ERROR_EMPTY_KEY,
   };
 
   typedef base::Callback<void(bool, CacheStorageError)> BoolAndErrorCallback;
   typedef base::Callback<void(int, CacheStorageError)> CacheAndErrorCallback;
   typedef base::Callback<void(const std::vector<std::string>&,
                               CacheStorageError)> StringsAndErrorCallback;
 
-  ServiceWorkerCacheStorage(
-      const base::FilePath& origin_path,
-      bool memory_only,
-      const scoped_refptr<base::MessageLoopProxy>& callback_loop);
+  ServiceWorkerCacheStorage(const base::FilePath& origin_path,
+                            bool memory_only,
+                            base::SequencedTaskRunner* cache_task_runner);
 
   virtual ~ServiceWorkerCacheStorage();
 
   // Create a ServiceWorkerCache if it doesn't already exist and call the
   // callback with the cache's id. If it already
   // exists the callback is called with CACHE_STORAGE_ERROR_EXISTS.
   void CreateCache(const std::string& cache_name,
                    const CacheAndErrorCallback& callback);
 
   // Get the cache id for the given key. If not found returns
   // CACHE_STORAGE_ERROR_NOT_FOUND.
   void GetCache(const std::string& cache_name,
                 const CacheAndErrorCallback& callback);
 
   // Calls the callback with whether or not the cache exists.
   void HasCache(const std::string& cache_name,
                 const BoolAndErrorCallback& callback);
 
   // Deletes the cache if it exists. If it doesn't exist,
   // CACHE_STORAGE_ERROR_NOT_FOUND is returned.
   void DeleteCache(const std::string& cache_name,
                    const BoolAndErrorCallback& callback);
 
   // Calls the callback with a vector of cache names (keys) available.
   void EnumerateCaches(const StringsAndErrorCallback& callback);
 
   // TODO(jkarlin): Add match() function.
 
-  void InitializeCacheCallback(const ServiceWorkerCache* cache,
-                               const CacheAndErrorCallback& callback,
-                               bool success);
-
  private:
   class MemoryLoader;
   class SimpleCacheLoader;
   class CacheLoader;
 
   typedef IDMap<ServiceWorkerCache, IDMapOwnPointer> CacheMap;
   typedef CacheMap::KeyType CacheID;
   typedef std::map<std::string, CacheID> NameMap;
 
   ServiceWorkerCache* GetLoadedCache(const std::string& cache_name) const;
 
-  void LazyInit();
-  void InitCache(ServiceWorkerCache* cache);
+  // Initializer and its callback are below.
+  void LazyInit(const base::Closure& closure);
+  void LazyInitDidLoadIndex(
+      const base::Closure& callback,
+      scoped_ptr<std::vector<std::string> > indexed_cache_names);
+  void LazyInitIterateAndLoadCacheName(
+      const base::Closure& callback,
+      scoped_ptr<std::vector<std::string> > indexed_cache_names,
+      const std::vector<std::string>::const_iterator& iter,
+      scoped_ptr<ServiceWorkerCache> cache);
+  void LazyInitDone();
 
+  void DidCreateBackend(base::WeakPtr<ServiceWorkerCache> cache,
+                        const CacheAndErrorCallback& callback,
+                        bool success);
+
+  void AddCacheToMaps(scoped_ptr<ServiceWorkerCache> cache);
+
+  // The CreateCache callbacks are below.
+  void CreateCacheDidCreateCache(const std::string& cache_name,
+                                 const CacheAndErrorCallback& callback,
+                                 scoped_ptr<ServiceWorkerCache> cache);
+  void CreateCacheDidWriteIndex(const CacheAndErrorCallback& callback,
+                                base::WeakPtr<ServiceWorkerCache> cache,
+                                bool success);
+
+  // The DeleteCache callbacks are below.
+  void DeleteCacheDidWriteIndex(const std::string& cache_name,
+                                const BoolAndErrorCallback& callback,
+                                bool success);
+  void DeleteCacheDidCleanUp(const BoolAndErrorCallback& callback,
+                             bool success);
+
+  // Whether or not we've loaded the list of cache names into memory.
   bool initialized_;
+
+  // The list of operations waiting on initialization.
+  std::vector<base::Closure> init_callbacks_;
+
+  // The map of ServiceWorkerCache objects to their integer ids that
+  // ServiceWorkers reference.  Owns the cache objects.
   CacheMap cache_map_;
+
+  // The map of cache names to their integer ids.
   NameMap name_map_;
+
+  // The file path for this CacheStorage.
   base::FilePath origin_path_;
-  scoped_refptr<base::MessageLoopProxy> callback_loop_;
-  scoped_ptr<CacheLoader> cache_loader_;
+
+  // The TaskRunner to run file IO on.
+  scoped_refptr<base::SequencedTaskRunner> cache_task_runner_;
+
+  // Performs backend specific operations (memory vs disk).
+  scoped_refptr<CacheLoader> cache_loader_;
+
+  base::WeakPtrFactory<ServiceWorkerCacheStorage> weak_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerCacheStorage);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_CACHE_STORAGE_H_