Expose ServiceWorkerCache objects to ServiceWorkerCacheStorageManager clients.

content/browser/service_worker/service_worker_cache.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_H_
 #define CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_CACHE_H_
 
 #include "base/callback.h"
 #include "base/files/file_path.h"
+#include "base/memory/ref_counted.h"
 #include "base/memory/weak_ptr.h"
 #include "content/common/service_worker/service_worker_types.h"
 #include "net/base/completion_callback.h"
 #include "net/disk_cache/disk_cache.h"
 
 namespace net {
 class URLRequestContext;
 class IOBufferWithSize;
 }
 
 namespace storage {
 class BlobData;
 class BlobDataHandle;
 class BlobStorageContext;
 }
 
 namespace content {
 class ChromeBlobStorageContext;
 class ServiceWorkerRequestResponseHeaders;
 
 // TODO(jkarlin): Unload cache backend from memory once the cache object is no
 // longer referenced in javascript.
 
 // Represents a ServiceWorker Cache as seen in
 // https://slightlyoff.github.io/ServiceWorker/spec/service_worker/index.html.
 // InitializeIfNeeded must be called before calling the other public members.
-class CONTENT_EXPORT ServiceWorkerCache {
+class CONTENT_EXPORT ServiceWorkerCache
+    : public base::RefCounted<ServiceWorkerCache> {
  public:
   enum ErrorType {
     ErrorTypeOK = 0,
     ErrorTypeExists,
     ErrorTypeStorage,
     ErrorTypeNotFound
   };
   enum EntryIndex { INDEX_HEADERS = 0, INDEX_RESPONSE_BODY };
   typedef base::Callback<void(ErrorType)> ErrorCallback;
   typedef base::Callback<void(ErrorType,
                               scoped_ptr<ServiceWorkerResponse>,
                               scoped_ptr<storage::BlobDataHandle>)>
       ResponseCallback;
   typedef std::vector<ServiceWorkerFetchRequest> Requests;
   typedef base::Callback<void(ErrorType, scoped_ptr<Requests>)>
       RequestsCallback;
 
-  static scoped_ptr<ServiceWorkerCache> CreateMemoryCache(
+  static scoped_refptr<ServiceWorkerCache> CreateMemoryCache(
       net::URLRequestContext* request_context,
       base::WeakPtr<storage::BlobStorageContext> blob_context);
-  static scoped_ptr<ServiceWorkerCache> CreatePersistentCache(
+  static scoped_refptr<ServiceWorkerCache> CreatePersistentCache(
       const base::FilePath& path,
       net::URLRequestContext* request_context,
       base::WeakPtr<storage::BlobStorageContext> blob_context);
 
-  // Operations in progress will complete after the cache is deleted but pending
-  // operations (those operations waiting for init to finish) won't.
-  virtual ~ServiceWorkerCache();
-
   // Returns ErrorTypeNotFound if not found. The callback will always be called.
-  // |request| must remain valid until the callback is called.
   void Match(scoped_ptr<ServiceWorkerFetchRequest> request,
              const ResponseCallback& callback);
 
   // Puts the request and response object in the cache. The response body (if
   // present) is stored in the cache, but not the request body. Returns
-  // ErrorTypeOK on success. The callback will always be called. |request| and
-  // |response| must remain valid until the callback is called.
+  // ErrorTypeOK on success. The callback will always be called.
   void Put(scoped_ptr<ServiceWorkerFetchRequest> request,
            scoped_ptr<ServiceWorkerResponse> response,
            const ErrorCallback& callback);
 
   // Returns ErrorNotFound if not found. Otherwise deletes and returns
-  // ErrorTypeOK. The callback will always be called. |request| must remain
-  // valid until the callback is called.
+  // ErrorTypeOK. The callback will always be called.
   void Delete(scoped_ptr<ServiceWorkerFetchRequest> request,
               const ErrorCallback& callback);
 
   // TODO(jkarlin): Have keys take an optional ServiceWorkerFetchRequest.
   // Returns ErrorTypeOK and a vector of requests if there are no errors. The
   // callback will always be called.
   void Keys(const RequestsCallback& callback);
 
+  // Prevent further operations on this object and delete the backend.
+  void Close();
+
   void set_backend(scoped_ptr<disk_cache::Backend> backend) {
     backend_ = backend.Pass();
   }
 
   base::WeakPtr<ServiceWorkerCache> AsWeakPtr();
 
  private:
+  friend class base::RefCounted<ServiceWorkerCache>;
+
   struct KeysContext;
   typedef std::vector<disk_cache::Entry*> Entries;
 
   ServiceWorkerCache(const base::FilePath& path,
                      net::URLRequestContext* request_context,
                      base::WeakPtr<storage::BlobStorageContext> blob_context);
 
+  // Operations in progress will complete after the cache is deleted but pending
+  // operations (those operations waiting for init to finish) won't.
+  virtual ~ServiceWorkerCache();
+
   void PutImpl(scoped_ptr<ServiceWorkerFetchRequest> request,
                scoped_ptr<ServiceWorkerResponse> response,
                scoped_ptr<storage::BlobDataHandle> blob_data_handle,
                const ErrorCallback& callback);
 
   // Static callbacks for the Keys function.
   static void KeysDidOpenNextEntry(scoped_ptr<KeysContext> keys_context,
                                    int rv);
   static void KeysProcessNextEntry(scoped_ptr<KeysContext> keys_context,
                                    const Entries::iterator& iter);
   static void KeysDidReadHeaders(
       scoped_ptr<KeysContext> keys_context,
       const Entries::iterator& iter,
       scoped_ptr<ServiceWorkerRequestResponseHeaders> headers);
 
   // Loads the backend and calls the callback with the result (true for
   // success). The callback will always be called.
   void CreateBackend(const ErrorCallback& callback);
 
   void Init(const base::Closure& callback);
   void InitDone(ErrorType error);
 
+  // The backend can be deleted via the Close function at any time so always
+  // check for its existence before use.
   scoped_ptr<disk_cache::Backend> backend_;
   base::FilePath path_;
   net::URLRequestContext* request_context_;
   base::WeakPtr<storage::BlobStorageContext> blob_storage_context_;
   bool initialized_;
   std::vector<base::Closure> init_callbacks_;
 
   base::WeakPtrFactory<ServiceWorkerCache> weak_ptr_factory_;
 
   DISALLOW_COPY_AND_ASSIGN(ServiceWorkerCache);
 };
 
 }  // namespace content
 
 #endif  // CONTENT_BROWSER_SERVICE_WORKER_SERVICE_WORKER_CACHE_H_