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// Copyright 2018 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 "third_party/blink/renderer/platform/loader/fetch/buffering_bytes_consumer.h"
#include "base/feature_list.h"
#include "base/metrics/field_trial_params.h"
#include "third_party/blink/renderer/platform/wtf/std_lib_extras.h"
namespace blink {
namespace {
constexpr int32_t kDelayMilliseconds = 50;
} // namespace
// static
BufferingBytesConsumer* BufferingBytesConsumer::CreateWithDelay(
BytesConsumer* bytes_consumer,
scoped_refptr<base::SingleThreadTaskRunner> timer_task_runner) {
return MakeGarbageCollected<BufferingBytesConsumer>(
base::PassKey<BufferingBytesConsumer>(), bytes_consumer,
std::move(timer_task_runner),
base::TimeDelta::FromMilliseconds(kDelayMilliseconds));
}
// static
BufferingBytesConsumer* BufferingBytesConsumer::Create(
BytesConsumer* bytes_consumer) {
return MakeGarbageCollected<BufferingBytesConsumer>(
base::PassKey<BufferingBytesConsumer>(), bytes_consumer, nullptr,
base::TimeDelta());
}
BufferingBytesConsumer::BufferingBytesConsumer(
base::PassKey<BufferingBytesConsumer> key,
BytesConsumer* bytes_consumer,
scoped_refptr<base::SingleThreadTaskRunner> timer_task_runner,
base::TimeDelta buffering_start_delay)
: bytes_consumer_(bytes_consumer),
timer_(std::move(timer_task_runner),
this,
&BufferingBytesConsumer::OnTimerFired) {
bytes_consumer_->SetClient(this);
if (buffering_start_delay.is_zero()) {
MaybeStartBuffering();
return;
}
timer_.StartOneShot(buffering_start_delay, FROM_HERE);
}
BufferingBytesConsumer::~BufferingBytesConsumer() = default;
void BufferingBytesConsumer::MaybeStartBuffering() {
if (buffering_state_ != BufferingState::kDelayed)
return;
timer_.Stop();
buffering_state_ = BufferingState::kStarted;
BufferData();
}
void BufferingBytesConsumer::StopBuffering() {
timer_.Stop();
buffering_state_ = BufferingState::kStopped;
}
BytesConsumer::Result BufferingBytesConsumer::BeginRead(const char** buffer,
size_t* available) {
// Stop delaying buffering on the first read as it will no longer be safe to
// drain the underlying |bytes_consumer_| anyway.
MaybeStartBuffering();
if (buffer_.IsEmpty()) {
if (buffering_state_ != BufferingState::kStarted)
return bytes_consumer_->BeginRead(buffer, available);
if (has_seen_error_)
return Result::kError;
if (has_seen_end_of_data_) {
ClearClient();
return Result::kDone;
}
BufferData();
if (has_seen_error_)
return Result::kError;
if (buffer_.IsEmpty())
return has_seen_end_of_data_ ? Result::kDone : Result::kShouldWait;
}
DCHECK_LT(offset_for_first_chunk_, buffer_[0].size());
*buffer = buffer_[0].data() + offset_for_first_chunk_;
*available = buffer_[0].size() - offset_for_first_chunk_;
return Result::kOk;
}
BytesConsumer::Result BufferingBytesConsumer::EndRead(size_t read_size) {
if (buffer_.IsEmpty()) {
if (buffering_state_ != BufferingState::kStarted)
return bytes_consumer_->EndRead(read_size);
DCHECK(has_seen_error_);
return Result::kError;
}
DCHECK_LE(offset_for_first_chunk_ + read_size, buffer_[0].size());
offset_for_first_chunk_ += read_size;
if (offset_for_first_chunk_ == buffer_[0].size()) {
offset_for_first_chunk_ = 0;
buffer_.pop_front();
}
if (buffer_.IsEmpty() && has_seen_end_of_data_) {
ClearClient();
return Result::kDone;
}
return Result::kOk;
}
scoped_refptr<BlobDataHandle> BufferingBytesConsumer::DrainAsBlobDataHandle(
BlobSizePolicy policy) {
return bytes_consumer_->DrainAsBlobDataHandle(policy);
}
scoped_refptr<EncodedFormData> BufferingBytesConsumer::DrainAsFormData() {
return bytes_consumer_->DrainAsFormData();
}
mojo::ScopedDataPipeConsumerHandle BufferingBytesConsumer::DrainAsDataPipe() {
if (buffering_state_ != BufferingState::kStarted)
return bytes_consumer_->DrainAsDataPipe();
// We intentionally return an empty handle here, because returning a DataPipe
// may activate back pressure.
return {};
}
void BufferingBytesConsumer::SetClient(BytesConsumer::Client* client) {
client_ = client;
}
void BufferingBytesConsumer::ClearClient() {
client_ = nullptr;
}
void BufferingBytesConsumer::Cancel() {
ClearClient();
bytes_consumer_->Cancel();
}
BytesConsumer::PublicState BufferingBytesConsumer::GetPublicState() const {
if (buffer_.IsEmpty())
return bytes_consumer_->GetPublicState();
return PublicState::kReadableOrWaiting;
}
BytesConsumer::Error BufferingBytesConsumer::GetError() const {
return bytes_consumer_->GetError();
}
void BufferingBytesConsumer::Trace(Visitor* visitor) const {
visitor->Trace(bytes_consumer_);
visitor->Trace(client_);
visitor->Trace(timer_);
BytesConsumer::Trace(visitor);
BytesConsumer::Client::Trace(visitor);
}
void BufferingBytesConsumer::OnTimerFired(TimerBase*) {
MaybeStartBuffering();
}
void BufferingBytesConsumer::OnStateChange() {
BytesConsumer::Client* client = client_;
BufferData();
if (client)
client->OnStateChange();
}
void BufferingBytesConsumer::BufferData() {
if (buffering_state_ != BufferingState::kStarted)
return;
while (true) {
const char* p = nullptr;
size_t available = 0;
auto result = bytes_consumer_->BeginRead(&p, &available);
if (result == Result::kShouldWait)
return;
if (result == Result::kOk) {
Vector<char> chunk;
chunk.Append(p, SafeCast<wtf_size_t>(available));
buffer_.push_back(std::move(chunk));
result = bytes_consumer_->EndRead(available);
}
if (result == Result::kDone) {
has_seen_end_of_data_ = true;
ClearClient();
return;
}
if (result != Result::kOk) {
buffer_.clear();
has_seen_error_ = true;
ClearClient();
return;
}
}
}
} // namespace blink
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