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// Copyright 2012 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "components/no_state_prefetch/renderer/no_state_prefetch_helper.h"
#include "base/metrics/field_trial.h"
#include "base/metrics/histogram_macros.h"
#include "components/no_state_prefetch/common/no_state_prefetch_url_loader_throttle.h"
#include "content/public/renderer/render_frame.h"
#include "content/public/renderer/render_thread.h"
#include "third_party/blink/public/platform/browser_interface_broker_proxy.h"
#include "third_party/blink/public/web/web_local_frame.h"
namespace prerender {
NoStatePrefetchHelper::NoStatePrefetchHelper(
content::RenderFrame* render_frame,
const std::string& histogram_prefix)
: content::RenderFrameObserver(render_frame),
content::RenderFrameObserverTracker<NoStatePrefetchHelper>(render_frame),
histogram_prefix_(histogram_prefix),
start_time_(base::TimeTicks::Now()) {}
NoStatePrefetchHelper::~NoStatePrefetchHelper() = default;
// static
std::unique_ptr<blink::URLLoaderThrottle>
NoStatePrefetchHelper::MaybeCreateThrottle(
const blink::LocalFrameToken& frame_token) {
// Currently NoStatePrefetchHelper doesn't work on the background thread.
if (!content::RenderThread::IsMainThread()) {
return nullptr;
}
blink::WebLocalFrame* web_frame =
blink::WebLocalFrame::FromFrameToken(frame_token);
if (!web_frame) {
return nullptr;
}
content::RenderFrame* render_frame =
content::RenderFrame::FromWebFrame(web_frame);
auto* helper =
render_frame
? NoStatePrefetchHelper::Get(render_frame->GetMainRenderFrame())
: nullptr;
if (!helper) {
return nullptr;
}
mojo::PendingRemote<mojom::NoStatePrefetchCanceler> canceler;
render_frame->GetBrowserInterfaceBroker().GetInterface(
canceler.InitWithNewPipeAndPassReceiver());
auto throttle =
std::make_unique<NoStatePrefetchURLLoaderThrottle>(std::move(canceler));
helper->AddThrottle(*throttle);
return throttle;
}
// static.
bool NoStatePrefetchHelper::IsPrefetching(
const content::RenderFrame* render_frame) {
return NoStatePrefetchHelper::Get(render_frame) != nullptr;
}
void NoStatePrefetchHelper::DidDispatchDOMContentLoadedEvent() {
prefetch_finished_ = true;
if (prefetch_count_ == 0) {
SendPrefetchFinished();
}
}
void NoStatePrefetchHelper::OnDestruct() {
delete this;
}
void NoStatePrefetchHelper::AddThrottle(
NoStatePrefetchURLLoaderThrottle& throttle) {
// Keep track of how many pending throttles we have, as we want to defer
// sending the "prefetch finished" signal until they are destroyed. This is
// important since that signal tells the browser that it can tear down this
// renderer which could interrupt subresource prefetching.
prefetch_count_++;
throttle.set_destruction_closure(base::BindOnce(
&NoStatePrefetchHelper::OnThrottleDestroyed, weak_factory_.GetWeakPtr()));
}
void NoStatePrefetchHelper::OnThrottleDestroyed() {
if (--prefetch_count_ == 0 && prefetch_finished_) {
SendPrefetchFinished();
}
}
void NoStatePrefetchHelper::SendPrefetchFinished() {
DCHECK(prefetch_count_ == 0 && prefetch_finished_);
mojo::Remote<mojom::NoStatePrefetchCanceler> canceler;
render_frame()->GetBrowserInterfaceBroker().GetInterface(
canceler.BindNewPipeAndPassReceiver());
canceler->CancelNoStatePrefetchAfterSubresourcesDiscovered();
}
} // namespace prerender
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