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// Copyright 2021 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/optimization_guide/content/renderer/page_text_agent.h"
#include "base/functional/callback_helpers.h"
#include "content/public/renderer/render_frame.h"
#include "mojo/public/cpp/bindings/remote.h"
#include "third_party/blink/public/common/associated_interfaces/associated_interface_registry.h"
#include "third_party/blink/public/platform/web_string.h"
#include "third_party/blink/public/web/web_frame_content_dumper.h"
namespace optimization_guide {
namespace {
constexpr size_t kChunkSize = 4096;
std::optional<mojom::TextDumpEvent> LayoutEventAsMojoEvent(
blink::WebMeaningfulLayout layout_event) {
switch (layout_event) {
case blink::WebMeaningfulLayout::kFinishedParsing:
return mojom::TextDumpEvent::kFirstLayout;
case blink::WebMeaningfulLayout::kFinishedLoading:
return mojom::TextDumpEvent::kFinishedLoad;
default:
break;
}
return std::nullopt;
}
} // namespace
PageTextAgent::PageTextAgent(content::RenderFrame* frame)
: content::RenderFrameObserver(frame),
content::RenderFrameObserverTracker<PageTextAgent>(frame) {
if (!frame) {
// For unittesting.
return;
}
frame->GetAssociatedInterfaceRegistry()->AddInterface<mojom::PageTextService>(
base::BindRepeating(&PageTextAgent::Bind, weak_factory_.GetWeakPtr()));
}
PageTextAgent::~PageTextAgent() = default;
void PageTextAgent::Bind(
mojo::PendingAssociatedReceiver<mojom::PageTextService> receiver) {
receivers_.Add(this, std::move(receiver));
}
base::OnceCallback<void(scoped_refptr<const base::RefCountedString16>)>
PageTextAgent::MaybeRequestTextDumpOnLayoutEvent(
blink::WebMeaningfulLayout event,
uint32_t* max_size) {
// This code path is only supported for mainframes, when there is a frame.
if (render_frame() && !render_frame()->IsMainFrame()) {
return base::NullCallback();
}
std::optional<mojom::TextDumpEvent> mojo_event =
LayoutEventAsMojoEvent(event);
if (!mojo_event) {
return base::NullCallback();
}
auto requests_iter = requests_by_event_.find(*mojo_event);
if (requests_iter == requests_by_event_.end()) {
return base::NullCallback();
}
// Move the pending consumer remote out of the map. The map entry will be
// destroyed since it's not needed anymore, but the pending remote will be
// given to the callback for when the text is ready.
mojo::PendingRemote<mojom::PageTextConsumer> pending_consumer =
std::move(requests_iter->second.second);
*max_size = std::max(*max_size, requests_iter->second.first->max_size);
requests_by_event_.erase(*mojo_event);
return base::BindOnce(&PageTextAgent::OnPageTextDump,
weak_factory_.GetWeakPtr(),
std::move(pending_consumer));
}
void PageTextAgent::OnPageTextDump(
mojo::PendingRemote<mojom::PageTextConsumer> pending_consumer,
scoped_refptr<const base::RefCountedString16> content) {
mojo::Remote<mojom::PageTextConsumer> consumer;
consumer.Bind(std::move(pending_consumer));
if (content) {
for (size_t i = 0; i < content->as_string().size(); i += kChunkSize) {
// Take a substring of length |kChunkSize|, or whatever is left in
// |content|, whichever is less.
size_t chunk_size = std::min(kChunkSize, content->as_string().size() - i);
// Either mojo will end up making a copy of the string (if passed a const
// ref), or we will. Might as well just do it now to make this less
// complex, but std::move it.
std::u16string chunk = content->as_string().substr(i, chunk_size);
consumer->OnTextDumpChunk(std::move(chunk));
}
}
consumer->OnChunksEnd();
}
void PageTextAgent::DidFinishLoad() {
if (!render_frame()) {
return;
}
// Only subframes should use this code path.
if (render_frame()->IsMainFrame()) {
return;
}
// Only AMP subframes are supported.
if (!is_amp_page_) {
return;
}
auto requests_iter =
requests_by_event_.find(mojom::TextDumpEvent::kFinishedLoad);
if (requests_iter == requests_by_event_.end()) {
return;
}
mojo::PendingRemote<mojom::PageTextConsumer> pending_consumer =
std::move(requests_iter->second.second);
uint32_t max_size = requests_iter->second.first->max_size;
requests_by_event_.erase(mojom::TextDumpEvent::kFinishedLoad);
auto content = base::MakeRefCounted<const base::RefCountedString16>(
blink::WebFrameContentDumper::DumpFrameTreeAsText(
render_frame()->GetWebFrame(), max_size)
.Utf16());
OnPageTextDump(std::move(pending_consumer), std::move(content));
}
void PageTextAgent::DidStartNavigation(
const GURL& url,
std::optional<blink::WebNavigationType> navigation_type) {
is_amp_page_ = false;
// Note that |requests_by_event_| should NOT be reset here. Requests and
// navigations from the browser race with each other, and the text dump
// request normally wins. We don't want to drop a request when its navigation
// is just about to start.
}
void PageTextAgent::DidObserveLoadingBehavior(
blink::LoadingBehaviorFlag behavior) {
is_amp_page_ |=
behavior & blink::LoadingBehaviorFlag::kLoadingBehaviorAmpDocumentLoaded;
}
void PageTextAgent::RequestPageTextDump(
mojom::PageTextDumpRequestPtr request,
mojo::PendingRemote<mojom::PageTextConsumer> consumer) {
// Save the request and consumer until the event comes along.
mojom::TextDumpEvent event = request->event;
requests_by_event_.emplace(
event, std::make_pair(std::move(request), std::move(consumer)));
}
} // namespace optimization_guide
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