Mojo: Armed Watchers

content/child/url_response_body_consumer.cc

 // Copyright 2016 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/url_response_body_consumer.h"
 
 #include "base/auto_reset.h"
 #include "base/bind.h"
 #include "base/macros.h"
 #include "base/memory/ptr_util.h"
@@ skipping 30 matching lines @@
 };
 
 URLResponseBodyConsumer::URLResponseBodyConsumer(
     int request_id,
     ResourceDispatcher* resource_dispatcher,
     mojo::ScopedDataPipeConsumerHandle handle,
     scoped_refptr<base::SingleThreadTaskRunner> task_runner)
     : request_id_(request_id),
       resource_dispatcher_(resource_dispatcher),
       handle_(std::move(handle)),
-      handle_watcher_(FROM_HERE, task_runner),
+      handle_watcher_(FROM_HERE,
+                      mojo::SimpleWatcher::ArmingPolicy::MANUAL,
+                      task_runner),
       task_runner_(task_runner),
       has_seen_end_of_data_(!handle_.is_valid()) {
-  handle_watcher_.Start(
+  handle_watcher_.Watch(
       handle_.get(), MOJO_HANDLE_SIGNAL_READABLE,
       base::Bind(&URLResponseBodyConsumer::OnReadable, base::Unretained(this)));
-  task_runner_->PostTask(
-      FROM_HERE, base::Bind(&URLResponseBodyConsumer::OnReadable, AsWeakPtr(),
-                            MOJO_RESULT_OK));
+  handle_watcher_.ArmOrNotify();
 }
 
 URLResponseBodyConsumer::~URLResponseBodyConsumer() {}
 
 void URLResponseBodyConsumer::OnComplete(
     const ResourceRequestCompletionStatus& status) {
   if (has_been_cancelled_)
     return;
   has_received_completion_ = true;
   completion_status_ = status;
@@ skipping 14 matching lines @@
   OnReadable(MOJO_RESULT_OK);
 }
 
 void URLResponseBodyConsumer::Reclaim(uint32_t size) {
   MojoResult result = mojo::EndReadDataRaw(handle_.get(), size);
   DCHECK_EQ(MOJO_RESULT_OK, result);
 
   if (is_in_on_readable_)
     return;
 
-  task_runner_->PostTask(
-      FROM_HERE, base::Bind(&URLResponseBodyConsumer::OnReadable, AsWeakPtr(),
-                            MOJO_RESULT_OK));
+  handle_watcher_.ArmOrNotify();
 }
 
 void URLResponseBodyConsumer::OnReadable(MojoResult unused) {
   if (has_been_cancelled_ || has_seen_end_of_data_ || is_deferred_)
     return;
 
   DCHECK(!is_in_on_readable_);
   uint32_t num_bytes_consumed = 0;
 
   // Protect |this| as RequestPeer::OnReceivedData may call deref.
   scoped_refptr<URLResponseBodyConsumer> protect(this);
   base::AutoReset<bool> is_in_on_readable(&is_in_on_readable_, true);
 
   while (!has_been_cancelled_ && !is_deferred_) {
     const void* buffer = nullptr;
     uint32_t available = 0;
     MojoResult result = mojo::BeginReadDataRaw(
         handle_.get(), &buffer, &available, MOJO_READ_DATA_FLAG_NONE);
-    if (result == MOJO_RESULT_SHOULD_WAIT || result == MOJO_RESULT_BUSY)
+    if (result == MOJO_RESULT_SHOULD_WAIT) {
+      handle_watcher_.ArmOrNotify();
+      return;
+    }
+    if (result == MOJO_RESULT_BUSY)
       return;
     if (result == MOJO_RESULT_FAILED_PRECONDITION) {
       has_seen_end_of_data_ = true;
       NotifyCompletionIfAppropriate();
       return;
     }
     if (result != MOJO_RESULT_OK) {
       completion_status_.error_code = net::ERR_FAILED;
       has_seen_end_of_data_ = true;
       has_received_completion_ = true;
       NotifyCompletionIfAppropriate();
       return;
     }
     DCHECK_LE(num_bytes_consumed, kMaxNumConsumedBytesInTask);
     available =
         std::min(available, kMaxNumConsumedBytesInTask - num_bytes_consumed);
     if (available == 0) {
       // We've already consumed many bytes in this task. Defer the remaining
       // to the next task.
       result = mojo::EndReadDataRaw(handle_.get(), 0);
       DCHECK_EQ(result, MOJO_RESULT_OK);
-      task_runner_->PostTask(FROM_HERE,
-                             base::Bind(&URLResponseBodyConsumer::OnReadable,
-                                        AsWeakPtr(), MOJO_RESULT_OK));
+      handle_watcher_.ArmOrNotify();
       return;
     }
     num_bytes_consumed += available;
     ResourceDispatcher::PendingRequestInfo* request_info =
         resource_dispatcher_->GetPendingRequestInfo(request_id_);
     DCHECK(request_info);
 
     // Check whether this response data is compliant with our cross-site
     // document blocking policy. We only do this for the first chunk of data.
     if (request_info->site_isolation_metadata.get()) {
@@ skipping 15 matching lines @@
     return;
   // Cancel this instance in order not to notify twice.
   Cancel();
 
   resource_dispatcher_->DispatchMessage(
       ResourceMsg_RequestComplete(request_id_, completion_status_));
   // |this| may be deleted.
 }
 
 }  // namespace content