Use mojo for Chrome Loading, Part 1

content/browser/loader/mojo_async_resource_handler.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/browser/loader/mojo_async_resource_handler.h"
+
+#include <utility>
+
+#include "base/command_line.h"
+#include "base/containers/hash_tables.h"
+#include "base/logging.h"
+#include "base/macros.h"
+#include "base/metrics/histogram_macros.h"
+#include "base/strings/string_number_conversions.h"
+#include "base/time/time.h"
+#include "content/browser/loader/netlog_observer.h"
+#include "content/browser/loader/resource_dispatcher_host_impl.h"
+#include "content/browser/loader/resource_message_filter.h"
+#include "content/browser/loader/resource_request_info_impl.h"
+#include "content/common/resource_request_completion_status.h"
+#include "content/public/browser/resource_dispatcher_host_delegate.h"
+#include "content/public/common/resource_response.h"
+#include "net/base/io_buffer.h"
+#include "net/base/load_flags.h"
+#include "net/log/net_log.h"
+#include "net/url_request/redirect_info.h"
+
+namespace content {
+namespace {
+
+int maxAllocationSize = 1024 * 32;

[mmenke, 2016/05/25 16:17:20]

max_allocation_size, or better, g_max_allocation_size (As suggested, but not
required, by style guide).

[yhirano, 2016/05/26 15:42:44]

Thanks, done.

+
+void GetNumericArg(const std::string& name, int* result) {
+  const std::string& value =
+      base::CommandLine::ForCurrentProcess()->GetSwitchValueASCII(name);
+  if (!value.empty())
+    base::StringToInt(value, result);
+}
+
+void InitializeResourceBufferConstants() {
+  static bool did_init = false;
+  if (did_init)
+    return;
+  did_init = true;
+
+  GetNumericArg("resource-buffer-max-allocation-size", &maxAllocationSize);

[mmenke, 2016/05/25 16:17:20]

Wow..I was going to complain about this being weird and ugly, but it's just what
AsyncResourceHandler does.  :(

+}
+
+}  // namespace
+
+MojoAsyncResourceHandler::MojoAsyncResourceHandler(
+    net::URLRequest* request,
+    ResourceDispatcherHostImpl* rdh,
+    std::unique_ptr<mojom::URLLoader> url_loader,
+    mojom::URLLoaderClientPtr url_loader_client)
+    : ResourceHandler(request),
+      rdh_(rdh),
+      url_loader_(std::move(url_loader)),
+      url_loader_client_(std::move(url_loader_client)) {
+  DCHECK(url_loader_);
+  DCHECK(url_loader_client_);
+  InitializeResourceBufferConstants();
+}
+
+MojoAsyncResourceHandler::~MojoAsyncResourceHandler() {
+  if (has_checked_for_sufficient_resources_)
+    rdh_->FinishedWithResourcesForRequest(request());
+}
+
+void MojoAsyncResourceHandler::OnFollowRedirect(int request_id) {
+  NOTREACHED();
+}
+
+bool MojoAsyncResourceHandler::OnRequestRedirected(
+    const net::RedirectInfo& redirect_info,
+    ResourceResponse* response,
+    bool* defer) {
+  // Not implemented.
+  return false;
+}
+
+bool MojoAsyncResourceHandler::OnResponseStarted(ResourceResponse* response,
+                                                 bool* defer) {
+  // For changes to the main frame, inform the renderer of the new URL's
+  // per-host settings before the request actually commits.  This way the
+  // renderer will be able to set these precisely at the time the
+  // request commits, avoiding the possibility of e.g. zooming the old content
+  // or of having to layout the new content twice.
+
+  response_started_ticks_ = base::TimeTicks::Now();
+
+  const ResourceRequestInfoImpl* info = GetRequestInfo();
+  if (!info->filter())
+    return false;
+
+  if (rdh_->delegate()) {
+    rdh_->delegate()->OnResponseStarted(request(), info->GetContext(), response,
+                                        info->filter());
+  }
+
+  NetLogObserver::PopulateResponseInfo(request(), response);
+
+  // If the parent handler downloaded the resource to a file, grant the child
+  // read permissions on it.
+  if (!response->head.download_file_path.empty()) {
+    rdh_->RegisterDownloadedTempFile(info->GetChildID(), info->GetRequestID(),
+                                     response->head.download_file_path);
+  }
+
+  response->head.request_start = request()->creation_time();
+  response->head.response_start = base::TimeTicks::Now();
+  sent_received_response_message_ = true;
+  url_loader_client_->OnReceiveResponse(response->head);
+  return true;
+}
+
+bool MojoAsyncResourceHandler::OnWillStart(const GURL& url, bool* defer) {
+  return true;
+}
+
+bool MojoAsyncResourceHandler::OnBeforeNetworkStart(const GURL& url,
+                                                    bool* defer) {
+  return true;
+}
+
+bool MojoAsyncResourceHandler::OnWillRead(scoped_refptr<net::IOBuffer>* buf,
+                                          int* buf_size,
+                                          int min_size) {
+  DCHECK_EQ(-1, min_size);
+
+  if (!CheckForSufficientResource())
+    return false;
+
+  void* buffer = nullptr;
+  uint32_t available = 0;
+  if (!writer_.is_valid()) {
+    MojoCreateDataPipeOptions options;
+    options.struct_size = sizeof(MojoCreateDataPipeOptions);
+    options.flags = MOJO_CREATE_DATA_PIPE_OPTIONS_FLAG_NONE;
+    options.element_num_bytes = 1;
+    options.capacity_num_bytes = maxAllocationSize;
+    mojo::DataPipe data_pipe(options);
+
+    writer_ = std::move(data_pipe.producer_handle);
+    ResourceMessageFilter* filter = GetRequestInfo()->filter();
+    if (filter) {
+      url_loader_client_->OnStartLoadingResponseBody(
+          std::move(data_pipe.consumer_handle));
+    }
+  }
+  if (!writer_.is_valid()) {
+    controller()->CancelWithError(net::ERR_FAILED);
+    return false;
+  }
+
+  MojoResult result = mojo::BeginWriteDataRaw(
+      writer_.get(), &buffer, &available, MOJO_WRITE_DATA_FLAG_NONE);
+  // SHOULD_WAIT should be handled in OnReadCompleted.
+  if (result == MOJO_RESULT_OK) {
+    *buf = new net::WrappedIOBuffer(static_cast<const char*>(buffer));
+    *buf_size = available;
+    return true;
+  }
+  controller()->CancelWithError(net::ERR_FAILED);
+  return false;
+}
+
+bool MojoAsyncResourceHandler::OnReadCompleted(int bytes_read, bool* defer) {
+  DCHECK_GE(bytes_read, 0);
+
+  if (!bytes_read)
+    return true;
+
+  MojoResult result = mojo::EndWriteDataRaw(writer_.get(), bytes_read);
+  if (result != MOJO_RESULT_OK)
+    return false;
+  void* buffer = nullptr;
+  uint32_t available = 0;
+  // To see if the handle is still writable.
+  result = mojo::BeginWriteDataRaw(writer_.get(), &buffer, &available,
+                                   MOJO_WRITE_DATA_FLAG_NONE);
+  if (result == MOJO_RESULT_SHOULD_WAIT ||
+      (result == MOJO_RESULT_OK && available == 0)) {
+    *defer = did_defer_ = true;
+    OnDefer();
+    handle_watcher_.Start(writer_.get(), MOJO_HANDLE_SIGNAL_WRITABLE,
+                          MOJO_DEADLINE_INDEFINITE,
+                          base::Bind(&MojoAsyncResourceHandler::OnWritable,
+                                     base::Unretained(this)));
+  }
+  if (result == MOJO_RESULT_OK)
+    mojo::EndWriteDataRaw(writer_.get(), 0);
+  return true;
+}
+
+void MojoAsyncResourceHandler::OnDataDownloaded(int bytes_downloaded) {
+  // Not implemented.

[kinuko, 2016/05/26 08:43:12]

NOTIMPLEMENTED() ?

[yhirano, 2016/05/26 15:42:44]

I think it's not good to output error messages.

+}
+
+void MojoAsyncResourceHandler::OnResponseCompleted(
+    const net::URLRequestStatus& status,
+    const std::string& security_info,
+    bool* defer) {
+  const ResourceRequestInfoImpl* info = GetRequestInfo();
+  if (!info->filter())
+    return;
+
+  // TODO(gavinp): Remove this CHECK when we figure out the cause of
+  // http://crbug.com/124680 . This check mirrors closely check in
+  // WebURLLoaderImpl::OnCompletedRequest that routes this message to a WebCore
+  // ResourceHandleInternal which asserts on its state and crashes. By crashing
+  // when the message is sent, we should get better crash reports.
+  CHECK(status.status() != net::URLRequestStatus::SUCCESS ||
+        sent_received_response_message_);

[kinuko, 2016/05/26 08:43:12]

Not entirely sure if we should mirror these CHECK and TODO comment...

[yhirano, 2016/05/26 15:42:44]

Deleted.

+
+  int error_code = status.error();
+  bool was_ignored_by_handler = info->WasIgnoredByHandler();
+
+  DCHECK(status.status() != net::URLRequestStatus::IO_PENDING);
+  // If this check fails, then we're in an inconsistent state because all
+  // requests ignored by the handler should be canceled (which should result in
+  // the ERR_ABORTED error code).
+  DCHECK(!was_ignored_by_handler || error_code == net::ERR_ABORTED);
+
+  // TODO(mkosiba): Fix up cases where we create a URLRequestStatus
+  // with a status() != SUCCESS and an error_code() == net::OK.
+  if (status.status() == net::URLRequestStatus::CANCELED &&
+      error_code == net::OK) {
+    error_code = net::ERR_ABORTED;
+  } else if (status.status() == net::URLRequestStatus::FAILED &&
+             error_code == net::OK) {
+    error_code = net::ERR_FAILED;
+  }
+
+  ResourceRequestCompletionStatus request_complete_data;
+  request_complete_data.error_code = error_code;
+  request_complete_data.was_ignored_by_handler = was_ignored_by_handler;
+  request_complete_data.exists_in_cache = request()->response_info().was_cached;
+  request_complete_data.security_info = security_info;
+  request_complete_data.completion_time = base::TimeTicks::Now();
+  request_complete_data.encoded_data_length =
+      request()->GetTotalReceivedBytes();
+
+  url_loader_client_->OnComplete(request_complete_data);
+
+  if (status.is_success())
+    RecordHistogram();
+}
+
+void MojoAsyncResourceHandler::ResumeIfDeferred() {
+  if (did_defer_) {
+    did_defer_ = false;
+    request()->LogUnblocked();
+    controller()->Resume();
+  }
+}
+
+void MojoAsyncResourceHandler::OnDefer() {
+  request()->LogBlockedBy("MojoAsyncResourceHandler");
+}
+
+bool MojoAsyncResourceHandler::CheckForSufficientResource() {
+  if (has_checked_for_sufficient_resources_)
+    return true;
+  has_checked_for_sufficient_resources_ = true;
+
+  if (rdh_->HasSufficientResourcesForRequest(request()))
+    return true;
+
+  controller()->CancelWithError(net::ERR_INSUFFICIENT_RESOURCES);
+  return false;
+}
+
+void MojoAsyncResourceHandler::RecordHistogram() {
+  int64_t elapsed_time =
+      (base::TimeTicks::Now() - response_started_ticks_).InMicroseconds();
+  int64_t encoded_length = request()->GetTotalReceivedBytes();
+  if (encoded_length < 2 * 1024) {
+    // The resource was smaller than the smallest required buffer size.
+    UMA_HISTOGRAM_CUSTOM_COUNTS("Net.ResourceLoader.ResponseStartToEnd.LT_2kB",
+                                elapsed_time, 1, 100000, 100);
+  } else if (encoded_length < 32 * 1024) {
+    // The resource was smaller than single chunk.
+    UMA_HISTOGRAM_CUSTOM_COUNTS("Net.ResourceLoader.ResponseStartToEnd.LT_32kB",
+                                elapsed_time, 1, 100000, 100);
+  } else if (encoded_length < 512 * 1024) {
+    // The resource was smaller than single chunk.
+    UMA_HISTOGRAM_CUSTOM_COUNTS(
+        "Net.ResourceLoader.ResponseStartToEnd.LT_512kB", elapsed_time, 1,
+        100000, 100);
+  } else {
+    UMA_HISTOGRAM_CUSTOM_COUNTS(
+        "Net.ResourceLoader.ResponseStartToEnd.Over_512kB", elapsed_time, 1,
+        100000, 100);

[kinuko, 2016/05/26 08:43:12]

We should probably use different histogram names for them, or just removing
these at all for now (these were added for tracking benefits of IPC-related
optimizations, having these as is here doesn't make much sense)

[yhirano, 2016/05/26 15:42:44]

Done.

+  }
+}
+
+void MojoAsyncResourceHandler::OnWritable(MojoResult unused) {
+  ResumeIfDeferred();
+}
+
+}  // namespace content