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// Copyright 2015 Google Inc. All Rights Reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "cobalt/media/fetcher_buffered_data_source.h"
#include <algorithm>
#include <string>
#include "base/bind.h"
#include "base/callback_helpers.h"
#include "base/string_number_conversions.h"
#include "net/http/http_response_headers.h"
#include "net/http/http_status_code.h"
namespace cobalt {
namespace media {
namespace {
const uint32 kBackwardBytes = 256 * 1024;
const uint32 kInitialForwardBytes = 3 * 256 * 1024;
const uint32 kInitialBufferCapacity = kBackwardBytes + kInitialForwardBytes;
} // namespace
using base::CircularBufferShell;
FetcherBufferedDataSource::FetcherBufferedDataSource(
const scoped_refptr<base::MessageLoopProxy>& message_loop, const GURL& url,
const csp::SecurityCallback& security_callback,
network::NetworkModule* network_module)
: message_loop_(message_loop),
url_(url),
network_module_(network_module),
buffer_(kInitialBufferCapacity, CircularBufferShell::kReserve),
buffer_offset_(0),
error_occured_(false),
last_request_offset_(0),
last_request_size_(0),
last_read_position_(0),
pending_read_position_(0),
pending_read_size_(0),
pending_read_data_(NULL),
security_callback_(security_callback) {
DCHECK(message_loop_);
DCHECK(network_module);
}
FetcherBufferedDataSource::~FetcherBufferedDataSource() {
if (cancelable_create_fetcher_closure_) {
cancelable_create_fetcher_closure_->Cancel();
}
}
void FetcherBufferedDataSource::Read(int64 position, int size, uint8* data,
const ReadCB& read_cb) {
DCHECK_GE(position, 0);
DCHECK_GE(size, 0);
if (position < 0 || size < 0) {
read_cb.Run(kInvalidSize);
return;
}
base::AutoLock auto_lock(lock_);
Read_Locked(static_cast<uint64>(position), static_cast<size_t>(size), data,
read_cb);
}
void FetcherBufferedDataSource::Stop() {
{
base::AutoLock auto_lock(lock_);
if (!pending_read_cb_.is_null()) {
base::ResetAndReturn(&pending_read_cb_).Run(0);
}
// From this moment on, any call to Read() should be treated as an error.
// Note that we cannot reset |fetcher_| here because of:
// 1. Fetcher has to be destroyed on the thread that it is created, however
// Stop() is usually called from the pipeline thread where |fetcher_| is
// created on the web thread.
// 2. We cannot post a task to the web thread to destroy |fetcher_| as the
// web thread is blocked by WMPI::Destroy().
// Once error_occured_ is set to true, the fetcher callbacks return
// immediately so it is safe to destroy |fetcher_| inside the dtor.
error_occured_ = true;
}
}
bool FetcherBufferedDataSource::GetSize(int64* size_out) {
base::AutoLock auto_lock(lock_);
if (total_size_of_resource_) {
*size_out = static_cast<int64>(total_size_of_resource_.value());
DCHECK_GE(*size_out, 0);
} else {
*size_out = kInvalidSize;
}
return *size_out != kInvalidSize;
}
void FetcherBufferedDataSource::OnURLFetchResponseStarted(
const net::URLFetcher* source) {
DCHECK(message_loop_->BelongsToCurrentThread());
base::AutoLock auto_lock(lock_);
if (fetcher_.get() != source || error_occured_) {
return;
}
if (!source->GetStatus().is_success()) {
// The error will be handled on OnURLFetchComplete()
error_occured_ = true;
return;
} else if (source->GetResponseCode() == -1) {
// Could be a file URL, so we won't expect headers.
return;
}
// In the event of a redirect, re-check the security policy.
if (source->GetURL() != source->GetOriginalURL()) {
if (!security_callback_.is_null() &&
!security_callback_.Run(source->GetURL(), true /*did redirect*/)) {
error_occured_ = true;
if (!pending_read_cb_.is_null()) {
base::ResetAndReturn(&pending_read_cb_).Run(-1);
}
return;
}
}
scoped_refptr<net::HttpResponseHeaders> headers =
source->GetResponseHeaders();
DCHECK(headers);
uint64 first_byte_offset = 0;
if (headers->response_code() == net::HTTP_PARTIAL_CONTENT) {
int64 first_byte_position = -1;
int64 last_byte_position = -1;
int64 instance_length = -1;
bool is_range_valid =
headers &&
headers->GetContentRange(&first_byte_position, &last_byte_position,
&instance_length);
if (is_range_valid) {
if (first_byte_position >= 0) {
first_byte_offset = static_cast<uint64>(first_byte_position);
}
if (!total_size_of_resource_ && instance_length > 0) {
total_size_of_resource_ = static_cast<uint64>(instance_length);
}
}
}
DCHECK_LE(first_byte_offset, last_request_offset_);
if (first_byte_offset < last_request_offset_) {
last_request_size_ += last_request_offset_ - first_byte_offset;
last_request_offset_ = first_byte_offset;
}
}
void FetcherBufferedDataSource::OnURLFetchDownloadData(
const net::URLFetcher* source, scoped_ptr<std::string> download_data) {
UNREFERENCED_PARAMETER(source);
DCHECK(message_loop_->BelongsToCurrentThread());
size_t size = download_data->size();
if (size == 0) {
return;
}
const uint8* data = reinterpret_cast<const uint8*>(download_data->data());
base::AutoLock auto_lock(lock_);
if (fetcher_.get() != source || error_occured_) {
return;
}
size = static_cast<size_t>(std::min<uint64>(size, last_request_size_));
if (size == 0) {
// The server side doesn't support range request. Delete the fetcher to
// stop the current request.
fetcher_.reset();
ProcessPendingRead_Locked();
return;
}
// Because we can only append data into the buffer_. We just check if the
// position of the first byte of the newly received data is overlapped with
// the range of the buffer_. If not, we can discard all data in the buffer_
// as there is no way to represent a gap or to prepend data.
if (last_request_offset_ < buffer_offset_ ||
last_request_offset_ > buffer_offset_ + buffer_.GetLength()) {
buffer_.Clear();
buffer_offset_ = last_request_offset_;
}
// If there is any overlapping, modify data/size accordingly.
if (buffer_offset_ + buffer_.GetLength() > last_request_offset_) {
uint64 difference =
buffer_offset_ + buffer_.GetLength() - last_request_offset_;
difference = std::min<uint64>(difference, size);
data += difference;
size -= difference;
last_request_offset_ += difference;
}
// If we are overflow, remove some data from the front of the buffer_.
if (buffer_.GetLength() + size > buffer_.GetMaxCapacity()) {
size_t bytes_skipped;
buffer_.Skip(buffer_.GetLength() + size - buffer_.GetMaxCapacity(),
&bytes_skipped);
// "+ 0" converts buffer_.GetMaxCapacity() into a r-value to avoid link
// error.
DCHECK_EQ(buffer_.GetLength() + size, buffer_.GetMaxCapacity() + 0);
buffer_offset_ += bytes_skipped;
}
size_t bytes_written;
bool result = buffer_.Write(data, size, &bytes_written);
DCHECK(result);
DCHECK_EQ(size, bytes_written);
last_request_offset_ += bytes_written;
last_request_size_ -= bytes_written;
ProcessPendingRead_Locked();
}
void FetcherBufferedDataSource::OnURLFetchComplete(
const net::URLFetcher* source) {
DCHECK(message_loop_->BelongsToCurrentThread());
base::AutoLock auto_lock(lock_);
if (fetcher_.get() != source || error_occured_) {
return;
}
const net::URLRequestStatus& status = source->GetStatus();
if (status.is_success()) {
if (total_size_of_resource_ && last_request_size_ != 0) {
total_size_of_resource_ = buffer_offset_ + buffer_.GetLength();
}
} else {
LOG(ERROR)
<< "FetcherBufferedDataSource::OnURLFetchComplete called with error "
<< status.error();
error_occured_ = true;
buffer_.Clear();
}
fetcher_.reset();
ProcessPendingRead_Locked();
}
void FetcherBufferedDataSource::CreateNewFetcher() {
DCHECK(message_loop_->BelongsToCurrentThread());
base::AutoLock auto_lock(lock_);
fetcher_.reset();
DCHECK_GE(static_cast<int64>(last_request_offset_), 0);
DCHECK_GE(static_cast<int64>(last_request_size_), 0);
// Check if there was an error or if the request is blocked by csp.
if (error_occured_ ||
(!security_callback_.is_null() && !security_callback_.Run(url_, false))) {
error_occured_ = true;
if (!pending_read_cb_.is_null()) {
base::ResetAndReturn(&pending_read_cb_).Run(-1);
}
return;
}
fetcher_.reset(net::URLFetcher::Create(url_, net::URLFetcher::GET, this));
fetcher_->SetRequestContext(network_module_->url_request_context_getter());
fetcher_->DiscardResponse();
std::string range_request =
"Range: bytes=" + base::Uint64ToString(last_request_offset_) + "-" +
base::Uint64ToString(last_request_offset_ + last_request_size_ - 1);
fetcher_->AddExtraRequestHeader(range_request);
fetcher_->Start();
}
void FetcherBufferedDataSource::Read_Locked(uint64 position, size_t size,
uint8* data,
const ReadCB& read_cb) {
lock_.AssertAcquired();
DCHECK(data);
DCHECK(!read_cb.is_null());
DCHECK(pending_read_cb_.is_null()); // One read operation at the same time.
if (error_occured_) {
read_cb.Run(-1);
return;
}
// Clamp the request to valid range of the resource if its size is known.
if (total_size_of_resource_) {
position = std::min(position, total_size_of_resource_.value());
if (size + position > total_size_of_resource_.value()) {
size = static_cast<size_t>(total_size_of_resource_.value() - position);
}
}
last_read_position_ = position;
if (size == 0) {
read_cb.Run(0);
return;
}
// Fulfill the read request now if we have the data.
if (position >= buffer_offset_ &&
position + size <= buffer_offset_ + buffer_.GetLength()) {
// All data is available
size_t bytes_peeked;
buffer_.Peek(data, size, static_cast<size_t>(position - buffer_offset_),
&bytes_peeked);
DCHECK_EQ(bytes_peeked, size);
DCHECK_GE(static_cast<int>(bytes_peeked), 0);
read_cb.Run(static_cast<int>(bytes_peeked));
// If we have a large buffer size, it could be ideal if we can keep sending
// small requests when the read offset is far from the beginning of the
// buffer. However as the ShellDemuxer will cache many frames and the
// buffer we are using is usually small, we will just avoid sending requests
// here to make code simple.
return;
}
// Save the read request as we are unable to fulfill it now.
pending_read_cb_ = read_cb;
pending_read_position_ = position;
pending_read_size_ = size;
pending_read_data_ = data;
// Combine the range of the buffer and any ongoing fetch to see if the read
// is overlapped with it.
if (fetcher_) {
uint64 begin = last_request_offset_;
uint64 end = last_request_offset_ + last_request_size_;
if (last_request_offset_ >= buffer_offset_ &&
last_request_offset_ <= buffer_offset_ + buffer_.GetLength()) {
begin = buffer_offset_;
}
if (position >= begin && position < end) {
// The read is overlapped with existing request, just wait.
return;
}
}
// Now we have to issue a new fetch and we no longer care about the range
// of the current fetch in progress if there is any. Ideally the request
// range starts at |last_read_position_ - kBackwardBytes| with length of
// buffer_.GetMaxCapacity().
if (last_read_position_ > kBackwardBytes) {
last_request_offset_ = last_read_position_ - kBackwardBytes;
} else {
last_request_offset_ = 0;
}
size_t required_size = static_cast<size_t>(
last_read_position_ - last_request_offset_ + pending_read_size_);
if (required_size > buffer_.GetMaxCapacity()) {
// The capacity of the current buffer is not large enough to hold the
// pending read.
size_t new_capacity =
std::max<size_t>(buffer_.GetMaxCapacity() * 2, required_size);
buffer_.IncreaseMaxCapacityTo(new_capacity);
}
last_request_size_ = buffer_.GetMaxCapacity();
if (last_request_offset_ >= buffer_offset_ &&
last_request_offset_ <= buffer_offset_ + buffer_.GetLength()) {
// Part of the Read() can be fulfilled by the current buffer and current
// request but cannot be fulfilled by the current request but we have to
// send another request to retrieve the rest.
last_request_size_ -=
buffer_offset_ + buffer_.GetLength() - last_request_offset_;
last_request_offset_ = buffer_offset_ + buffer_.GetLength();
}
if (cancelable_create_fetcher_closure_) {
cancelable_create_fetcher_closure_->Cancel();
}
base::Closure create_fetcher_closure = base::Bind(
&FetcherBufferedDataSource::CreateNewFetcher, base::Unretained(this));
cancelable_create_fetcher_closure_ =
new CancelableClosure(create_fetcher_closure);
message_loop_->PostTask(FROM_HERE,
cancelable_create_fetcher_closure_->AsClosure());
}
void FetcherBufferedDataSource::ProcessPendingRead_Locked() {
lock_.AssertAcquired();
if (!pending_read_cb_.is_null()) {
Read_Locked(pending_read_position_, pending_read_size_, pending_read_data_,
base::ResetAndReturn(&pending_read_cb_));
}
}
FetcherBufferedDataSource::CancelableClosure::CancelableClosure(
const base::Closure& closure)
: closure_(closure) {
DCHECK(!closure.is_null());
}
void FetcherBufferedDataSource::CancelableClosure::Cancel() {
base::AutoLock auto_lock(lock_);
closure_.Reset();
}
base::Closure FetcherBufferedDataSource::CancelableClosure::AsClosure() {
return base::Bind(&CancelableClosure::Call, this);
}
void FetcherBufferedDataSource::CancelableClosure::Call() {
base::AutoLock auto_lock(lock_);
// closure_.Run() has to be called when the lock is acquired to avoid race
// condition.
if (!closure_.is_null()) {
base::ResetAndReturn(&closure_).Run();
}
}
} // namespace media
} // namespace cobalt