[BlobAsync] Renderer support for blob file writing.

content/child/blob_storage/blob_transport_controller.h

Index: content/child/blob_storage/blob_transport_controller.h
diff --git a/content/child/blob_storage/blob_transport_controller.h b/content/child/blob_storage/blob_transport_controller.h
index c9c62ce55ba69e36a4b5bcd6f7ddcc52c421057e..dac489bd9f46fa76338d10c0d863a0624596058b 100644
--- a/content/child/blob_storage/blob_transport_controller.h
+++ b/content/child/blob_storage/blob_transport_controller.h
@@ -12,6 +12,7 @@
 #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"
@@ -24,6 +25,7 @@ namespace base {
 template <typename T>
 struct DefaultLazyInstanceTraits;
 class SingleThreadTaskRunner;
+class TaskRunner;
 }
 
 namespace storage {
@@ -33,6 +35,7 @@ struct BlobItemBytesResponse;
 }
 
 namespace IPC {
+class Message;
 class Sender;
 }
 
@@ -53,6 +56,8 @@ class ThreadSafeSender;
 // 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
@@ -63,18 +68,21 @@ class CONTENT_EXPORT BlobTransportController {
   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);
@@ -86,12 +94,26 @@ class CONTENT_EXPORT BlobTransportController {
   }
 
  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);
@@ -103,16 +125,19 @@ class CONTENT_EXPORT BlobTransportController {
   // 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(
@@ -120,7 +145,11 @@ class CONTENT_EXPORT BlobTransportController {
       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
@@ -128,7 +157,7 @@ class CONTENT_EXPORT BlobTransportController {
   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);
 };