[BlobAsync] Renderer support for blob file writing.

content/child/blob_storage/blob_transport_controller.h

 // Copyright 2015 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_CHILD_BLOB_STORAGE_BLOB_TRANSPORT_CONTROLLER_H_
 #define CONTENT_CHILD_BLOB_STORAGE_BLOB_TRANSPORT_CONTROLLER_H_
 
 #include <stddef.h>
 
 #include <map>
 #include <memory>
 #include <string>
 #include <vector>
 
+#include "base/callback_forward.h"
 #include "base/gtest_prod_util.h"
 #include "base/macros.h"
 #include "base/memory/ref_counted.h"
 #include "base/memory/shared_memory_handle.h"
 #include "content/common/content_export.h"
 #include "ipc/ipc_platform_file.h"
 #include "storage/common/blob_storage/blob_storage_constants.h"
 
 namespace base {
 template <typename T>
 struct DefaultLazyInstanceTraits;
 class SingleThreadTaskRunner;
+class TaskRunner;
 }
 
 namespace storage {
 class DataElement;
 struct BlobItemBytesRequest;
 struct BlobItemBytesResponse;
 }
 
 namespace IPC {
+class Message;
 class Sender;
 }
 
 namespace content {
 
 class BlobConsolidation;
 class ThreadSafeSender;
 
 // This class is used to manage all the asynchronous transporation of blobs from
 // the Renderer to the Browser process, where it's handling the Renderer side.
 // The function of this class is to:
 // * Be a lazy singleton,
 // * hold all of the blob data that is being transported to the Browser process,
 // * create the blob item 'descriptions' for the browser,
 // * include shortcut data in the descriptions,
 // * generate responses to blob memory requests, and
 // * send IPC responses.
 // Must be used on the IO thread.
 class CONTENT_EXPORT BlobTransportController {
  public:
+  using IPCSender = base::Callback<void(std::unique_ptr<IPC::Message>)>;
+
   static BlobTransportController* GetInstance();
 
   // This kicks off a blob transfer to the browser thread, which involves
   // sending an IPC message and storing the blob consolidation object. Designed
   // to be called by the main thread or a worker thread.
   // This also calls ChildProcess::AddRefProcess to keep our process around
   // while we transfer.
   static void InitiateBlobTransfer(
       const std::string& uuid,
       const std::string& content_type,
-      std::unique_ptr<BlobConsolidation> consolidation,
+      scoped_refptr<BlobConsolidation> consolidation,
       scoped_refptr<ThreadSafeSender> sender,
       base::SingleThreadTaskRunner* io_runner,
       scoped_refptr<base::SingleThreadTaskRunner> main_runner);
 
-  // This responds to the request using the sender.
+  // This responds to the request using the |ipc_sender| callback. If we need
+  // to save files then the call will happen asynchronously.

[michaeln, 2016/04/21 18:51:43]

maybe also mention that a single call to OnMemoryRequest can result in multiple
response messages being sent

   void OnMemoryRequest(
       const std::string& uuid,
       const std::vector<storage::BlobItemBytesRequest>& requests,
       std::vector<base::SharedMemoryHandle>* memory_handles,
       const std::vector<IPC::PlatformFileForTransit>& file_handles,
-      IPC::Sender* sender);
+      scoped_refptr<base::TaskRunner> io_runner,

[michaeln, 2016/04/21 01:58:41]

this method can only be called on the io thread so this arg shouldnt be needed,
i think you can use from with the method base::ThreadTaskRunnerHandle::Get()

[dmurph, 2016/04/22 22:37:10]

Done.

+      base::TaskRunner* file_runner,
+      const IPCSender& ipc_sender);

[michaeln, 2016/04/21 01:58:41]

we generally use the IPC::Sender interface for this

[dmurph, 2016/04/22 22:37:10]

Done.

 
   void OnCancel(const std::string& uuid,
                 storage::IPCBlobCreationCancelCode code);
 
   void OnDone(const std::string& uuid);
 
   bool IsTransporting(const std::string& uuid) {
     return blob_storage_.find(uuid) != blob_storage_.end();
   }
 
  private:
+  friend struct base::DefaultLazyInstanceTraits<BlobTransportController>;
   friend class BlobTransportControllerTest;
   FRIEND_TEST_ALL_PREFIXES(BlobTransportControllerTest, Descriptions);
   FRIEND_TEST_ALL_PREFIXES(BlobTransportControllerTest, Responses);
   FRIEND_TEST_ALL_PREFIXES(BlobTransportControllerTest, SharedMemory);
+  FRIEND_TEST_ALL_PREFIXES(BlobTransportControllerTest, Disk);
   FRIEND_TEST_ALL_PREFIXES(BlobTransportControllerTest, ResponsesErrors);
 
+  using ResponseCallback = base::Callback<void(
+      const std::vector<storage::BlobItemBytesResponse>& /* responses */)>;
+  using CancelCallback =
+      base::Callback<void(storage::IPCBlobCreationCancelCode /* reason */)>;
+
+  enum class ResponsesStatus {
+    BLOB_NOT_FOUND,
+    SHARED_MEMORY_MAP_FAILED,
+    PENDING_IO,
+    SUCCESS
+  };
+
   static void GetDescriptions(BlobConsolidation* consolidation,
                               size_t max_data_population,
                               std::vector<storage::DataElement>* out);
 
   BlobTransportController();
   ~BlobTransportController();
 
   // Clears all internal state. If our map wasn't previously empty, then we call
   // ChildProcess::ReleaseProcess to release our previous reference.
   void ClearForTesting();
 
-  enum class ResponsesStatus {
-    BLOB_NOT_FOUND,
-    SHARED_MEMORY_MAP_FAILED,
-    SUCCESS
-  };
-  friend struct base::DefaultLazyInstanceTraits<BlobTransportController>;
+  void SendResponses(
+      const IPCSender& ipc_sender,
+      const std::string& uuid,
+      const std::vector<storage::BlobItemBytesResponse>& responses);
+
+  void SendCancelAndReleaseConsolidation(
+      const IPCSender& ipc_sender,
+      const std::string& uuid,
+      storage::IPCBlobCreationCancelCode reason);
 
   void StoreBlobDataForRequests(
       const std::string& uuid,
-      std::unique_ptr<BlobConsolidation> consolidation,
+      scoped_refptr<BlobConsolidation> consolidation,
       scoped_refptr<base::SingleThreadTaskRunner> main_runner);
 
   ResponsesStatus GetResponses(
       const std::string& uuid,
       const std::vector<storage::BlobItemBytesRequest>& requests,
       std::vector<base::SharedMemoryHandle>* memory_handles,
       const std::vector<IPC::PlatformFileForTransit>& file_handles,
-      std::vector<storage::BlobItemBytesResponse>* output);
+      std::vector<storage::BlobItemBytesResponse>* output,
+      scoped_refptr<base::TaskRunner> io_runner,

[michaeln, 2016/04/21 01:58:41]

io_runner may not needed here for the same reason

[dmurph, 2016/04/22 22:37:10]

Done.

+      base::TaskRunner* file_runner,
+      const ResponseCallback& response_callback,
+      const CancelCallback& error_callback);

[michaeln, 2016/04/21 01:58:41]

ditto IPC::Sender

Since IPC::Sender would be a rawptr type, we'd need to be careful to not use a
dangling pointer. We generally do that with binding methods to objects via a
weakptr, and invalidating the weakptrs at an appropiate time

BlobTransportController::GetResponses(...) {
  // do stuff
  StartSomeAsyncStep(base::Bind(BlobTransportController::OnGotResponses),
                     weak_factory_.GetWeakPtr(), ...);
}

BlobTransportController::OnGotResponses(...) {
  // do stuff and produce
  sender->Send(msg)
}

// The filter would have to call this method
// upon nulling out its sender_ data member.
BlobTransportController::CancelAll() {
  blob_storage_.clear();
  weak_factory_.InvalidateWeakPtrs();
}

[kinuko, 2016/04/21 07:54:34]

Btw-- why don't we use ThreadSafeSender here and else?

[dmurph, 2016/04/22 22:37:10]

I don't have a thread safe version, I just have the IPC::Sender* from the
message filter.  I switched to using the raw pointer, but then letting the
client cancel running requests to invalidate the callbacks that use it.

That was after a discussion w/ Michael.

 
   // Deletes the consolidation, and if we removed the last consolidation from
   // our map, we call ChildProcess::ReleaseProcess to release our previous
   // reference.
   void ReleaseBlobConsolidation(const std::string& uuid);
 
   scoped_refptr<base::SingleThreadTaskRunner> main_thread_runner_;
-  std::map<std::string, std::unique_ptr<BlobConsolidation>> blob_storage_;
+  std::map<std::string, scoped_refptr<BlobConsolidation>> blob_storage_;
 
   DISALLOW_COPY_AND_ASSIGN(BlobTransportController);
 };
 
 }  // namespace content
 #endif  // CONTENT_CHILD_BLOB_STORAGE_BLOB_TRANSPORT_CONTROLLER_H_