[BlobAsync] Renderer support for blob file writing.

content/child/blob_storage/blob_transport_controller.cc

 // 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.
 
 #include "content/child/blob_storage/blob_transport_controller.h"
 
+#include <limits>
 #include <utility>
 #include <vector>
 
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/callback.h"
+#include "base/files/file.h"
 #include "base/lazy_instance.h"
+#include "base/location.h"
+#include "base/memory/ptr_util.h"
 #include "base/memory/scoped_vector.h"
 #include "base/memory/shared_memory.h"
 #include "base/single_thread_task_runner.h"
 #include "base/stl_util.h"
+#include "base/task_runner.h"
 #include "content/child/blob_storage/blob_consolidation.h"
 #include "content/child/child_process.h"
 #include "content/child/thread_safe_sender.h"
 #include "content/common/fileapi/webblob_messages.h"
+#include "ipc/ipc_message.h"
 #include "ipc/ipc_sender.h"
 #include "storage/common/blob_storage/blob_item_bytes_request.h"
 #include "storage/common/blob_storage/blob_item_bytes_response.h"
 #include "storage/common/data_element.h"
 #include "third_party/WebKit/public/platform/Platform.h"
 
+using base::File;
 using base::SharedMemory;
 using base::SharedMemoryHandle;
 using storage::BlobItemBytesRequest;
 using storage::BlobItemBytesResponse;
 using storage::IPCBlobItemRequestStrategy;
 using storage::DataElement;
 using storage::kBlobStorageIPCThresholdBytes;
 
+using storage::BlobItemBytesResponse;
+using storage::BlobItemBytesRequest;
+using storage::IPCBlobCreationCancelCode;
+
 namespace content {
-
-using storage::IPCBlobCreationCancelCode;
+using ResponseCallback = base::Callback<void(
+    const std::vector<storage::BlobItemBytesResponse>& /* responses */)>;
+using CancelCallback =
+    base::Callback<void(storage::IPCBlobCreationCancelCode /* reason */)>;
 
 using ConsolidatedItem = BlobConsolidation::ConsolidatedItem;
 using ReadStatus = BlobConsolidation::ReadStatus;
 
 namespace {
 static base::LazyInstance<BlobTransportController>::Leaky g_controller =
     LAZY_INSTANCE_INITIALIZER;
 
 // This keeps the process alive while blobs are being transferred.
 // These need to be called on the main thread.
 void IncChildProcessRefCount() {
   blink::Platform::current()->suddenTerminationChanged(false);
   ChildProcess::current()->AddRefProcess();
 }
 
 void DecChildProcessRefCount() {
   blink::Platform::current()->suddenTerminationChanged(true);
   ChildProcess::current()->ReleaseProcess();
 }
+
+bool WriteSingleChunk(base::File* file,
+                      size_t total_read,
+                      const char* memory,
+                      size_t size) {
+  size_t written = 0;
+  size_t max_int = static_cast<size_t>(std::numeric_limits<int>::max());
+  while (written < size) {
+    size_t writing_size = std::min(max_int, size - written);
+    int actual_written =
+        file->WriteAtCurrentPos(memory, static_cast<int>(writing_size));
+    if (actual_written < 0) {
+      LOG(ERROR) << "Error writing to file " << actual_written;
+      return false;
+    }
+    written += writing_size;
+  }
+  return true;
+}
+
+bool WriteSingleRequestToDisk(const BlobConsolidation* consolidation,
+                              const BlobItemBytesRequest& request,
+                              const IPC::PlatformFileForTransit& transit_file) {
+  File file = IPC::PlatformFileForTransitToFile(transit_file);
+  if (!file.IsValid())
+    return false;
+  CHECK_LE(request.handle_offset,
+           static_cast<uint64_t>(std::numeric_limits<int64_t>::max()));
+  int64_t seek_distance =
+      file.Seek(File::FROM_BEGIN, static_cast<int64_t>(request.handle_offset));
+  if (seek_distance < 0) {
+    LOG(ERROR) << "Error seeking " << request.handle_offset << " in file, got "
+               << seek_distance
+               << ". File error: " << File::ErrorToString(file.error_details());
+    return false;
+  }
+  BlobConsolidation::ReadStatus status = consolidation->VisitMemory(
+      request.renderer_item_index, request.renderer_item_offset, request.size,
+      base::Bind(&WriteSingleChunk, &file));
+  // We need to release the file so we don't automatically close the file.
+  file.TakePlatformFile();
+  return status == ReadStatus::OK;
+}
+
+void WriteDiskRequests(
+    scoped_refptr<BlobConsolidation> consolidation,
+    std::unique_ptr<std::vector<BlobItemBytesRequest>> requests,
+    const std::vector<IPC::PlatformFileForTransit>& file_handles,
+    const ResponseCallback& response_callback,
+    const CancelCallback& error_callback,
+    scoped_refptr<base::TaskRunner> io_task_runner) {
+  for (const auto& request : *requests) {
+    bool success = WriteSingleRequestToDisk(consolidation.get(), request,
+                                            file_handles[request.handle_index]);
+    if (!success) {
+      io_task_runner->PostTask(
+          FROM_HERE, base::Bind(error_callback,
+                                IPCBlobCreationCancelCode::FILE_WRITE_FAILED));
+      return;
+    }
+    io_task_runner->PostTask(
+        FROM_HERE,
+        base::Bind(response_callback,
+                   std::vector<BlobItemBytesResponse>{
+                       BlobItemBytesResponse(request.request_number)}));

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

is BlobItemBytesResponse.time_file_modified not needed? maybe it's used
elsewhere?

[dmurph, 2016/04/22 22:37:09]

Oh right, I need to add that.

+  }
+}
 }  // namespace
 
 BlobTransportController* BlobTransportController::GetInstance() {
   return g_controller.Pointer();
 }
 
 // static
 void BlobTransportController::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) {
   if (main_runner->BelongsToCurrentThread()) {
     IncChildProcessRefCount();
   } else {
     main_runner->PostTask(FROM_HERE, base::Bind(&IncChildProcessRefCount));
   }
 
   std::vector<storage::DataElement> descriptions;
   std::set<std::string> referenced_blobs = consolidation->referenced_blobs();
   BlobTransportController::GetDescriptions(
       consolidation.get(), kBlobStorageIPCThresholdBytes, &descriptions);
   // I post the task first to make sure that we store our consolidation before
   // we get a request back from the browser.
   io_runner->PostTask(
       FROM_HERE,
       base::Bind(&BlobTransportController::StoreBlobDataForRequests,
                  base::Unretained(BlobTransportController::GetInstance()), uuid,
-                 base::Passed(std::move(consolidation)),
-                 base::Passed(std::move(main_runner))));
+                 base::Passed(&consolidation), base::Passed(&main_runner)));
   // TODO(dmurph): Merge register and start messages.
   sender->Send(new BlobStorageMsg_RegisterBlobUUID(uuid, content_type, "",
                                                    referenced_blobs));
   sender->Send(new BlobStorageMsg_StartBuildingBlob(uuid, descriptions));
 }
 
 void BlobTransportController::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,
+    base::TaskRunner* file_runner,
+    const IPCSender& ipc_sender) {
   std::vector<storage::BlobItemBytesResponse> responses;
-  ResponsesStatus status =
-      GetResponses(uuid, requests, memory_handles, file_handles, &responses);
+  ResponsesStatus status = GetResponses(
+      uuid, requests, memory_handles, file_handles, &responses,
+      std::move(io_runner), file_runner,
+      base::Bind(&BlobTransportController::SendResponses,
+                 base::Unretained(this), ipc_sender, uuid),
+      base::Bind(&BlobTransportController::SendCancelAndReleaseConsolidation,
+                 base::Unretained(this), ipc_sender, uuid));
 
   switch (status) {
     case ResponsesStatus::BLOB_NOT_FOUND:
       // sender->Send(new BlobStorageMsg_CancelBuildingBlob(uuid,

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

is this needed?

[dmurph, 2016/04/22 22:37:09]

Probably not. Removed.

       // IPCBlobCreationCancelCode::UNKNOWN));
       return;
     case ResponsesStatus::SHARED_MEMORY_MAP_FAILED:
       // This would happen if the renderer process doesn't have enough memory
       // to map the shared memory, which is possible if we don't have much
       // memory. If this scenario happens often, we could delay the response
       // until we have enough memory.  For now we just fail.
       CHECK(false) << "Unable to map shared memory to send blob " << uuid
                    << ".";
       break;
     case ResponsesStatus::SUCCESS:
+    case ResponsesStatus::PENDING_IO:
       break;
   }
 
-  sender->Send(new BlobStorageMsg_MemoryItemResponse(uuid, responses));
+  if (!responses.empty())
+    ipc_sender.Run(base::WrapUnique(

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

As coded, the GetResponses helper is responsible for sending the async messages
and its caller is responsible for sending the immediate messages? Seems like an
unnecessary split of responsibility. As a simplification, I think you should
consider hoisting all of GetResponses in to this method, and getting rid of the
helper. 

OnMemoryRequest produces some number of ipc messages in response, perhaps
asyncly. I think that lends itself well to testing, call it, examine the ipcsink
for messages expected immediately,  RunTillIdle() and examine expected async
messages.

[dmurph, 2016/04/22 22:37:09]

Ok, done, check it out.

[dmurph, 2016/04/22 22:37:09]

sgtm.

+        new BlobStorageMsg_MemoryItemResponse(uuid, responses)));
 }
 
 void BlobTransportController::OnCancel(
     const std::string& uuid,
     storage::IPCBlobCreationCancelCode code) {
   DVLOG(1) << "Received blob cancel for blob " << uuid
            << " with code: " << static_cast<int>(code);
   ReleaseBlobConsolidation(uuid);
 }
 
@@ skipping 60 matching lines @@
 BlobTransportController::~BlobTransportController() {}
 
 void BlobTransportController::ClearForTesting() {
   if (!blob_storage_.empty() && main_thread_runner_) {
     main_thread_runner_->PostTask(FROM_HERE,
                                   base::Bind(&DecChildProcessRefCount));
   }
   blob_storage_.clear();
 }
 
+void BlobTransportController::SendResponses(
+    const IPCSender& ipc_sender,
+    const std::string& uuid,
+    const std::vector<storage::BlobItemBytesResponse>& responses) {
+  ipc_sender.Run(
+      base::WrapUnique(new BlobStorageMsg_MemoryItemResponse(uuid, responses)));
+}
+
+void BlobTransportController::SendCancelAndReleaseConsolidation(
+    const IPCSender& ipc_sender,
+    const std::string& uuid,
+    storage::IPCBlobCreationCancelCode reason) {
+  ipc_sender.Run(
+      base::WrapUnique(new BlobStorageMsg_CancelBuildingBlob(uuid, reason)));
+  ReleaseBlobConsolidation(uuid);
+}
+
 void BlobTransportController::StoreBlobDataForRequests(
     const std::string& uuid,
-    std::unique_ptr<BlobConsolidation> consolidation,
+    scoped_refptr<BlobConsolidation> consolidation,
     scoped_refptr<base::SingleThreadTaskRunner> main_runner) {
   if (!main_thread_runner_.get()) {
     main_thread_runner_ = std::move(main_runner);
   }
   blob_storage_[uuid] = std::move(consolidation);
 }
 
 BlobTransportController::ResponsesStatus BlobTransportController::GetResponses(
     const std::string& uuid,
     const std::vector<BlobItemBytesRequest>& requests,
     std::vector<SharedMemoryHandle>* memory_handles,
     const std::vector<IPC::PlatformFileForTransit>& file_handles,
-    std::vector<BlobItemBytesResponse>* out) {
+    std::vector<BlobItemBytesResponse>* out,
+    scoped_refptr<base::TaskRunner> io_runner,
+    base::TaskRunner* file_runner,
+    const ResponseCallback& response_callback,
+    const CancelCallback& error_callback) {
   DCHECK(out->empty());
   auto it = blob_storage_.find(uuid);
   if (it == blob_storage_.end())
     return ResponsesStatus::BLOB_NOT_FOUND;
 
   BlobConsolidation* consolidation = it->second.get();
   const auto& consolidated_items = consolidation->consolidated_items();
 
+  scoped_ptr<std::vector<BlobItemBytesRequest>> file_requests(
+      new std::vector<BlobItemBytesRequest>());
+
   // Since we can be writing to the same shared memory handle from multiple
   // requests, we keep them in a vector and lazily create them.
   ScopedVector<SharedMemory> opened_memory;
   opened_memory.resize(memory_handles->size());
   for (const BlobItemBytesRequest& request : requests) {
     DCHECK_LT(request.renderer_item_index, consolidated_items.size())
         << "Invalid item index";
 
     const ConsolidatedItem& item =
         consolidated_items[request.renderer_item_index];
     DCHECK_LE(request.renderer_item_offset + request.size, item.length)
         << "Invalid data range";
     DCHECK_EQ(item.type, DataElement::TYPE_BYTES) << "Invalid element type";
 
-    out->push_back(BlobItemBytesResponse(request.request_number));
     switch (request.transport_strategy) {
       case IPCBlobItemRequestStrategy::IPC: {
+        out->push_back(BlobItemBytesResponse(request.request_number));
         BlobItemBytesResponse& response = out->back();
         ReadStatus status = consolidation->ReadMemory(
             request.renderer_item_index, request.renderer_item_offset,
             request.size, response.allocate_mutable_data(request.size));
         DCHECK(status == ReadStatus::OK)
             << "Error reading from consolidated blob: "
             << static_cast<int>(status);
         break;
       }
       case IPCBlobItemRequestStrategy::SHARED_MEMORY: {
+        out->push_back(BlobItemBytesResponse(request.request_number));
         DCHECK_LT(request.handle_index, memory_handles->size())
             << "Invalid handle index.";
         SharedMemory* memory = opened_memory[request.handle_index];
         if (!memory) {
           SharedMemoryHandle& handle = (*memory_handles)[request.handle_index];
           DCHECK(SharedMemory::IsHandleValid(handle));
           std::unique_ptr<SharedMemory> shared_memory(
               new SharedMemory(handle, false));
           if (!shared_memory->Map(request.size))
             return ResponsesStatus::SHARED_MEMORY_MAP_FAILED;
           memory = shared_memory.get();
           opened_memory[request.handle_index] = shared_memory.release();
         }
         CHECK(memory->memory()) << "Couldn't map memory for blob transfer.";
         ReadStatus status = consolidation->ReadMemory(
             request.renderer_item_index, request.renderer_item_offset,
             request.size,
             static_cast<char*>(memory->memory()) + request.handle_offset);
         DCHECK(status == ReadStatus::OK)
             << "Error reading from consolidated blob: "
             << static_cast<int>(status);
         break;
       }
       case IPCBlobItemRequestStrategy::FILE:
-        NOTREACHED() << "TODO(dmurph): Not implemented.";
+        DCHECK_LT(request.handle_index, file_handles.size())
+            << "Invalid handle index.";
+        file_requests->push_back(request);
         break;
       case IPCBlobItemRequestStrategy::UNKNOWN:
         NOTREACHED();
         break;
     }
   }
-  return ResponsesStatus::SUCCESS;
+  if (file_requests->empty()) {
+    return ResponsesStatus::SUCCESS;
+  }
+  file_runner->PostTask(
+      FROM_HERE,
+      base::Bind(&WriteDiskRequests, consolidation,
+                 base::Passed(&file_requests), file_handles, response_callback,
+                 error_callback, base::Passed(&io_runner)));

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

Passing in a reply task runner seems odd. I'd expect the caller to expect to be
called back on the same thread, and pass in a callback that proxies to the other
thread if necessary so this utility is ignorant of that complexity.

I think this is a good place to use PostTaskAndReply where the reply is
delivered to a method of this class which then sends the results via ipc.

[dmurph, 2016/04/22 22:37:09]

Done.

+  return ResponsesStatus::PENDING_IO;
 }
 
 void BlobTransportController::ReleaseBlobConsolidation(
     const std::string& uuid) {
   if (blob_storage_.erase(uuid)) {
     main_thread_runner_->PostTask(FROM_HERE,
                                   base::Bind(&DecChildProcessRefCount));
   }
 }
 
 }  // namespace content