fuchsia/http/url_loader_impl.cc - chromium/src - Git at Google

 // 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 "fuchsia/http/url_loader_impl.h"

 #include "base/fuchsia/fuchsia_logging.h"
 #include "base/message_loop/message_loop_current.h"
 #include "base/task/post_task.h"
 #include "fuchsia/base/mem_buffer_util.h"
 #include "net/base/chunked_upload_data_stream.h"
 #include "net/base/net_errors.h"
 #include "net/http/http_response_headers.h"
 #include "net/url_request/redirect_info.h"

 namespace oldhttp = ::fuchsia::net::oldhttp;

 namespace {
 // Capacity, in bytes, for buffers used to move data from client requests or
 // server responses.
 const size_t kReadCapacity = 1024;

 // The number of active requests. Used for testing.
 int g_active_requests = 0;

 // Converts |buffer| into a URLBody with the body set to a buffer. Returns
 // nullptr when an error occurs.
 oldhttp::URLBodyPtr CreateURLBodyFromBuffer(net::GrowableIOBuffer* buffer) {
   oldhttp::URLBodyPtr body = oldhttp::URLBody::New();

   // The response buffer size is exactly the offset.
   size_t total_size = buffer->offset();

   body->set_buffer(cr_fuchsia::MemBufferFromString(
       base::StringPiece(buffer->StartOfBuffer(), total_size),
       "cr-http-url-body"));

   return body;
 }

 int NetErrorToHttpError(int net_error) {
   // TODO(https://crbug.com/875533): Convert the Chromium //net error to their
   // Fuchsia counterpart.
   return net_error;
 }

 oldhttp::HttpErrorPtr BuildError(int net_error) {
   if (net_error == net::OK) {
     return nullptr;
   }

   oldhttp::HttpErrorPtr error = oldhttp::HttpError::New();
   error->code = NetErrorToHttpError(net_error);
   error->description = net::ErrorToString(net_error);
   return error;
 }

 std::unique_ptr<net::UploadDataStream> UploadDataStreamFromZxSocket(
     zx::socket stream) {
   // TODO(http://crbug.com/875534): Write a ZxStreamUploadStream class.
   std::unique_ptr<net::ChunkedUploadDataStream> upload_stream =
       std::make_unique<net::ChunkedUploadDataStream>(0);
   char buffer[kReadCapacity];
   size_t size = 0;
   zx_status_t result = ZX_OK;
   while (true) {
     result = stream.read(0, buffer, kReadCapacity, &size);
     if (result != ZX_OK) {
       ZX_DLOG(WARNING, result) << "zx_socket_read";
       return nullptr;
     }
     if (size < kReadCapacity) {
       upload_stream->AppendData(buffer, size, false);
       break;
     }
     upload_stream->AppendData(buffer, size, true);
   }

   return upload_stream;
 }

 std::unique_ptr<net::UploadDataStream> UploadDataStreamFromMemBuffer(
     fuchsia::mem::Buffer mem_buffer) {
   // TODO(http://crbug.com/875534): Write a ZxMemBufferUploadStream class.
   std::unique_ptr<net::ChunkedUploadDataStream> upload_stream =
       std::make_unique<net::ChunkedUploadDataStream>(0);

   char buffer[kReadCapacity];
   size_t size = mem_buffer.size;
   size_t offset = 0;
   zx_status_t result = ZX_OK;
   while (offset != size) {
     size_t length = std::min(size - offset, kReadCapacity);
     result = mem_buffer.vmo.read(buffer, offset, length);
     if (result != ZX_OK) {
       ZX_DLOG(WARNING, result) << "zx_vmo_read";
       return nullptr;
     }
     upload_stream->AppendData(buffer, length, false);
     offset += length;
   }

   return upload_stream;
 }

 }  // namespace

 URLLoaderImpl::URLLoaderImpl(std::unique_ptr<net::URLRequestContext> context,
                              fidl::InterfaceRequest<oldhttp::URLLoader> request)
     : binding_(this, std::move(request)),
       context_(std::move(context)),
       buffer_(new net::GrowableIOBuffer()),
       write_watch_(FROM_HERE) {
   binding_.set_error_handler([this](zx_status_t status) {
     ZX_LOG_IF(ERROR, status != ZX_ERR_PEER_CLOSED, status)
         << " URLLoader disconnected.";
     delete this;
   });
   g_active_requests++;
 }

 URLLoaderImpl::~URLLoaderImpl() {
   g_active_requests--;
 }

 int URLLoaderImpl::GetNumActiveRequestsForTests() {
   return g_active_requests;
 }

 void URLLoaderImpl::Start(oldhttp::URLRequest request, Callback callback) {
   if (net_request_) {
     callback(BuildResponse(net::ERR_IO_PENDING));
     return;
   }

   done_callback_ = std::move(callback);
   net_error_ = net::OK;

   // Create the URLRequest and set this object as the delegate.
   net_request_ = context_->CreateRequest(GURL(request.url),
                                          net::RequestPriority::MEDIUM, this);
   net_request_->set_method(request.method);

   // Set extra headers.
   if (request.headers) {
     for (oldhttp::HttpHeader header : *(request.headers)) {
       net_request_->SetExtraRequestHeaderByName(header.name, header.value,
                                                 false);
     }
   }
   if (request.cache_mode == oldhttp::CacheMode::BYPASS_CACHE) {
     net_request_->SetExtraRequestHeaderByName("Cache-Control", "nocache",
                                               false);
   }

   std::unique_ptr<net::UploadDataStream> upload_stream;
   // Set body.
   if (request.body) {
     if (request.body->is_stream()) {
       upload_stream =
           UploadDataStreamFromZxSocket(std::move(request.body->stream()));
     } else {
       upload_stream =
           UploadDataStreamFromMemBuffer(std::move(request.body->buffer()));
     }

     if (!upload_stream) {
       std::move(done_callback_)(BuildResponse(net::ERR_ACCESS_DENIED));
       return;
     }
     net_request_->set_upload(std::move(upload_stream));
   }

   auto_follow_redirects_ = request.auto_follow_redirects;
   response_body_mode_ = request.response_body_mode;

   // Start the request.
   net_request_->Start();
 }

 void URLLoaderImpl::FollowRedirect(Callback callback) {
   if (!net_request_ || auto_follow_redirects_ ||
       !net_request_->is_redirecting()) {
     callback(BuildResponse(net::ERR_INVALID_HANDLE));
   }

   done_callback_ = std::move(callback);
   net_request_->FollowDeferredRedirect(base::nullopt /* removed_headers */,
                                        base::nullopt /* modified_headers */);
 }

 void URLLoaderImpl::QueryStatus(QueryStatusCallback callback) {
   oldhttp::URLLoaderStatus status;

   if (!net_request_) {
     status.is_loading = false;
   } else if (net_request_->is_pending() || net_request_->is_redirecting()) {
     status.is_loading = true;
   } else {
     status.is_loading = false;
     status.error = BuildError(net_error_);
   }

   callback(std::move(status));
 }

 void URLLoaderImpl::OnReceivedRedirect(net::URLRequest* request,
                                        const net::RedirectInfo& redirect_info,
                                        bool* defer_redirect) {
   DCHECK_EQ(net_request_.get(), request);
   // Follow redirect depending on policy.
   *defer_redirect = !auto_follow_redirects_;

   if (!auto_follow_redirects_) {
     oldhttp::URLResponse response = BuildResponse(net::OK);
     response.redirect_method = redirect_info.new_method;
     response.redirect_url = redirect_info.new_url.spec();
     response.redirect_referrer = redirect_info.new_referrer;
     std::move(done_callback_)(std::move(response));
   }
 }

 void URLLoaderImpl::OnAuthRequired(net::URLRequest* request,
                                    const net::AuthChallengeInfo& auth_info) {
   NOTIMPLEMENTED();
   DCHECK_EQ(net_request_.get(), request);
   request->CancelAuth();
 }

 void URLLoaderImpl::OnCertificateRequested(
     net::URLRequest* request,
     net::SSLCertRequestInfo* cert_request_info) {
   NOTIMPLEMENTED();
   DCHECK_EQ(net_request_.get(), request);
   request->ContinueWithCertificate(nullptr, nullptr);
 }

 void URLLoaderImpl::OnSSLCertificateError(net::URLRequest* request,
                                           int net_error,
                                           const net::SSLInfo& ssl_info,
                                           bool fatal) {
   NOTIMPLEMENTED();
   DCHECK_EQ(net_request_.get(), request);
   request->Cancel();
 }

 void URLLoaderImpl::OnResponseStarted(net::URLRequest* request, int net_error) {
   DCHECK_EQ(net_request_.get(), request);
   net_error_ = net_error;

   // Return early if the request failed.
   if (net_error_ != net::OK) {
     std::move(done_callback_)(BuildResponse(net_error_));
     return;
   }

   // In stream mode, call the callback now and write to the socket.
   if (response_body_mode_ == oldhttp::ResponseBodyMode::STREAM ||
       response_body_mode_ == oldhttp::ResponseBodyMode::BUFFER_OR_STREAM) {
     zx::socket read_socket;
     zx_status_t result = zx::socket::create(0, &read_socket, &write_socket_);
     if (result != ZX_OK) {
       ZX_DLOG(WARNING, result) << "zx_socket_create";
       std::move(done_callback_)(BuildResponse(net::ERR_INSUFFICIENT_RESOURCES));
       return;
     }
     oldhttp::URLResponse response = BuildResponse(net::OK);
     response.body = oldhttp::URLBody::New();
     response.body->set_stream(std::move(read_socket));
     std::move(done_callback_)(std::move(response));
   }

   // In stream mode, the buffer is used as a temporary buffer to write to the
   // socket. In buffer mode, it is expanded as more of the response is read.
   buffer_->SetCapacity(kReadCapacity);

   ReadNextBuffer();
 }

 void URLLoaderImpl::OnReadCompleted(net::URLRequest* request, int bytes_read) {
   DCHECK_EQ(net_request_.get(), request);
   if (WriteResponseBytes(bytes_read)) {
     ReadNextBuffer();
   }
 }

 void URLLoaderImpl::OnZxHandleSignalled(zx_handle_t handle,
                                         zx_signals_t signals) {
   // We should never have to process signals we didn't ask for.
   DCHECK((ZX_CHANNEL_WRITABLE | ZX_CHANNEL_PEER_CLOSED) & signals);
   DCHECK_GT(buffered_bytes_, 0);

   if (signals & ZX_CHANNEL_PEER_CLOSED) {
     return;
   }

   if (WriteResponseBytes(buffered_bytes_))
     ReadNextBuffer();
   buffered_bytes_ = 0;
 }

 void URLLoaderImpl::ReadNextBuffer() {
   int net_result;
   do {
     net_result = net_request_->Read(buffer_.get(), kReadCapacity);
     if (net_result == net::ERR_IO_PENDING) {
       return;
     }
   } while (WriteResponseBytes(net_result));
 }

 bool URLLoaderImpl::WriteResponseBytes(int result) {
   if (result < 0) {
     // Signal read error back to the client.
     if (write_socket_) {
       DCHECK(response_body_mode_ == oldhttp::ResponseBodyMode::STREAM ||
              response_body_mode_ ==
                  oldhttp::ResponseBodyMode::BUFFER_OR_STREAM);
       // There is no need to check the return value of this call as there is no
       // way to recover from a failed socket close.
       write_socket_ = zx::socket();
     } else {
       DCHECK_EQ(response_body_mode_, oldhttp::ResponseBodyMode::BUFFER);
       std::move(done_callback_)(BuildResponse(result));
     }
     return false;
   }

   if (result == 0) {
     // Read complete.
     if (write_socket_) {
       DCHECK(response_body_mode_ == oldhttp::ResponseBodyMode::STREAM ||
              response_body_mode_ ==
                  oldhttp::ResponseBodyMode::BUFFER_OR_STREAM);
       // In socket mode, attempt to shut down the socket and close it.
       write_socket_.shutdown(ZX_SOCKET_SHUTDOWN_WRITE);
       write_socket_ = zx::socket();
     } else {
       DCHECK_EQ(response_body_mode_, oldhttp::ResponseBodyMode::BUFFER);
       // In buffer mode, build the response and call the callback.
       oldhttp::URLBodyPtr body = CreateURLBodyFromBuffer(buffer_.get());
       if (body) {
         oldhttp::URLResponse response = BuildResponse(net::OK);
         response.body = std::move(body);
         std::move(done_callback_)(std::move(response));
       } else {
         std::move(done_callback_)(
             BuildResponse(net::ERR_INSUFFICIENT_RESOURCES));
       }
     }
     return false;
   }

   // Write data to the response buffer or socket.
   if (write_socket_) {
     DCHECK(response_body_mode_ == oldhttp::ResponseBodyMode::STREAM ||
            response_body_mode_ == oldhttp::ResponseBodyMode::BUFFER_OR_STREAM);
     // In socket mode, attempt to write to the socket.
     zx_status_t status =
         write_socket_.write(0, buffer_->data(), result, nullptr);
     if (status == ZX_ERR_SHOULD_WAIT) {
       // Wait until the socket is writable again.
       buffered_bytes_ = result;
       base::MessageLoopCurrentForIO::Get()->WatchZxHandle(
           write_socket_.get(), false /* persistent */,
           ZX_SOCKET_WRITABLE | ZX_SOCKET_PEER_CLOSED, &write_watch_, this);
       return false;
     }
     if (status != ZX_OK) {
       // Something went wrong, attempt to shut down the socket and close it.
       ZX_DLOG(WARNING, status) << "zx_socket_write";
       write_socket_ = zx::socket();
       return false;
     }
   } else {
     DCHECK_EQ(response_body_mode_, oldhttp::ResponseBodyMode::BUFFER);
     // In buffer mode, expand the buffer.
     buffer_->SetCapacity(buffer_->capacity() + result);
     buffer_->set_offset(buffer_->offset() + result);
   }

   return true;
 }

 oldhttp::URLResponse URLLoaderImpl::BuildResponse(int net_error) {
   oldhttp::URLResponse response;

   response.error = BuildError(net_error);
   if (response.error) {
     return response;
   }

   if (net_request_->url().is_valid()) {
     response.url = net_request_->url().spec();
   }
   response.status_code = net_request_->GetResponseCode();

   net::HttpResponseHeaders* response_headers = net_request_->response_headers();
   if (response_headers) {
     response.status_line = response_headers->GetStatusLine();
     std::string mime_type;
     if (response_headers->GetMimeType(&mime_type)) {
       response.mime_type = mime_type;
     }
     std::string charset;
     if (response_headers->GetCharset(&charset)) {
       response.charset = charset;
     }

     size_t iter = 0;
     std::string header_name;
     std::string header_value;
     response.headers.emplace();
     while (response_headers->EnumerateHeaderLines(&iter, &header_name,
                                                   &header_value)) {
       oldhttp::HttpHeader header;
       header.name = header_name;
       header.value = header_value;
       response.headers->push_back(header);
     }
   }

   return response;
 }
	// 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 "fuchsia/http/url_loader_impl.h"

	#include "base/fuchsia/fuchsia_logging.h"
	#include "base/message_loop/message_loop_current.h"
	#include "base/task/post_task.h"
	#include "fuchsia/base/mem_buffer_util.h"
	#include "net/base/chunked_upload_data_stream.h"
	#include "net/base/net_errors.h"
	#include "net/http/http_response_headers.h"
	#include "net/url_request/redirect_info.h"

	namespace oldhttp = ::fuchsia::net::oldhttp;

	namespace {
	// Capacity, in bytes, for buffers used to move data from client requests or
	// server responses.
	const size_t kReadCapacity = 1024;

	// The number of active requests. Used for testing.
	int g_active_requests = 0;

	// Converts \|buffer\| into a URLBody with the body set to a buffer. Returns
	// nullptr when an error occurs.
	oldhttp::URLBodyPtr CreateURLBodyFromBuffer(net::GrowableIOBuffer* buffer) {
	oldhttp::URLBodyPtr body = oldhttp::URLBody::New();

	// The response buffer size is exactly the offset.
	size_t total_size = buffer->offset();

	body->set_buffer(cr_fuchsia::MemBufferFromString(
	base::StringPiece(buffer->StartOfBuffer(), total_size),
	"cr-http-url-body"));

	return body;
	}

	int NetErrorToHttpError(int net_error) {
	// TODO(https://crbug.com/875533): Convert the Chromium //net error to their
	// Fuchsia counterpart.
	return net_error;
	}

	oldhttp::HttpErrorPtr BuildError(int net_error) {
	if (net_error == net::OK) {
	return nullptr;
	}

	oldhttp::HttpErrorPtr error = oldhttp::HttpError::New();
	error->code = NetErrorToHttpError(net_error);
	error->description = net::ErrorToString(net_error);
	return error;
	}

	std::unique_ptr<net::UploadDataStream> UploadDataStreamFromZxSocket(
	zx::socket stream) {
	// TODO(http://crbug.com/875534): Write a ZxStreamUploadStream class.
	std::unique_ptr<net::ChunkedUploadDataStream> upload_stream =
	std::make_unique<net::ChunkedUploadDataStream>(0);
	char buffer[kReadCapacity];
	size_t size = 0;
	zx_status_t result = ZX_OK;
	while (true) {
	result = stream.read(0, buffer, kReadCapacity, &size);
	if (result != ZX_OK) {
	ZX_DLOG(WARNING, result) << "zx_socket_read";
	return nullptr;
	}
	if (size < kReadCapacity) {
	upload_stream->AppendData(buffer, size, false);
	break;
	}
	upload_stream->AppendData(buffer, size, true);
	}

	return upload_stream;
	}

	std::unique_ptr<net::UploadDataStream> UploadDataStreamFromMemBuffer(
	fuchsia::mem::Buffer mem_buffer) {
	// TODO(http://crbug.com/875534): Write a ZxMemBufferUploadStream class.
	std::unique_ptr<net::ChunkedUploadDataStream> upload_stream =
	std::make_unique<net::ChunkedUploadDataStream>(0);

	char buffer[kReadCapacity];
	size_t size = mem_buffer.size;
	size_t offset = 0;
	zx_status_t result = ZX_OK;
	while (offset != size) {
	size_t length = std::min(size - offset, kReadCapacity);
	result = mem_buffer.vmo.read(buffer, offset, length);
	if (result != ZX_OK) {
	ZX_DLOG(WARNING, result) << "zx_vmo_read";
	return nullptr;
	}
	upload_stream->AppendData(buffer, length, false);
	offset += length;
	}

	return upload_stream;
	}

	} // namespace

	URLLoaderImpl::URLLoaderImpl(std::unique_ptr<net::URLRequestContext> context,
	fidl::InterfaceRequest<oldhttp::URLLoader> request)
	: binding_(this, std::move(request)),
	context_(std::move(context)),
	buffer_(new net::GrowableIOBuffer()),
	write_watch_(FROM_HERE) {
	binding_.set_error_handler([this](zx_status_t status) {
	ZX_LOG_IF(ERROR, status != ZX_ERR_PEER_CLOSED, status)
	<< " URLLoader disconnected.";
	delete this;
	});
	g_active_requests++;
	}

	URLLoaderImpl::~URLLoaderImpl() {
	g_active_requests--;
	}

	int URLLoaderImpl::GetNumActiveRequestsForTests() {
	return g_active_requests;
	}

	void URLLoaderImpl::Start(oldhttp::URLRequest request, Callback callback) {
	if (net_request_) {
	callback(BuildResponse(net::ERR_IO_PENDING));
	return;
	}

	done_callback_ = std::move(callback);
	net_error_ = net::OK;

	// Create the URLRequest and set this object as the delegate.
	net_request_ = context_->CreateRequest(GURL(request.url),
	net::RequestPriority::MEDIUM, this);
	net_request_->set_method(request.method);

	// Set extra headers.
	if (request.headers) {
	for (oldhttp::HttpHeader header : *(request.headers)) {
	net_request_->SetExtraRequestHeaderByName(header.name, header.value,
	false);
	}
	}
	if (request.cache_mode == oldhttp::CacheMode::BYPASS_CACHE) {
	net_request_->SetExtraRequestHeaderByName("Cache-Control", "nocache",
	false);
	}

	std::unique_ptr<net::UploadDataStream> upload_stream;
	// Set body.
	if (request.body) {
	if (request.body->is_stream()) {
	upload_stream =
	UploadDataStreamFromZxSocket(std::move(request.body->stream()));
	} else {
	upload_stream =
	UploadDataStreamFromMemBuffer(std::move(request.body->buffer()));
	}

	if (!upload_stream) {
	std::move(done_callback_)(BuildResponse(net::ERR_ACCESS_DENIED));
	return;
	}
	net_request_->set_upload(std::move(upload_stream));
	}

	auto_follow_redirects_ = request.auto_follow_redirects;
	response_body_mode_ = request.response_body_mode;

	// Start the request.
	net_request_->Start();
	}

	void URLLoaderImpl::FollowRedirect(Callback callback) {
	if (!net_request_ \|\| auto_follow_redirects_ \|\|
	!net_request_->is_redirecting()) {
	callback(BuildResponse(net::ERR_INVALID_HANDLE));
	}

	done_callback_ = std::move(callback);
	net_request_->FollowDeferredRedirect(base::nullopt /* removed_headers */,
	base::nullopt /* modified_headers */);
	}

	void URLLoaderImpl::QueryStatus(QueryStatusCallback callback) {
	oldhttp::URLLoaderStatus status;

	if (!net_request_) {
	status.is_loading = false;
	} else if (net_request_->is_pending() \|\| net_request_->is_redirecting()) {
	status.is_loading = true;
	} else {
	status.is_loading = false;
	status.error = BuildError(net_error_);
	}

	callback(std::move(status));
	}

	void URLLoaderImpl::OnReceivedRedirect(net::URLRequest* request,
	const net::RedirectInfo& redirect_info,
	bool* defer_redirect) {
	DCHECK_EQ(net_request_.get(), request);
	// Follow redirect depending on policy.
	*defer_redirect = !auto_follow_redirects_;

	if (!auto_follow_redirects_) {
	oldhttp::URLResponse response = BuildResponse(net::OK);
	response.redirect_method = redirect_info.new_method;
	response.redirect_url = redirect_info.new_url.spec();
	response.redirect_referrer = redirect_info.new_referrer;
	std::move(done_callback_)(std::move(response));
	}
	}

	void URLLoaderImpl::OnAuthRequired(net::URLRequest* request,
	const net::AuthChallengeInfo& auth_info) {
	NOTIMPLEMENTED();
	DCHECK_EQ(net_request_.get(), request);
	request->CancelAuth();
	}

	void URLLoaderImpl::OnCertificateRequested(
	net::URLRequest* request,
	net::SSLCertRequestInfo* cert_request_info) {
	NOTIMPLEMENTED();
	DCHECK_EQ(net_request_.get(), request);
	request->ContinueWithCertificate(nullptr, nullptr);
	}

	void URLLoaderImpl::OnSSLCertificateError(net::URLRequest* request,
	int net_error,
	const net::SSLInfo& ssl_info,
	bool fatal) {
	NOTIMPLEMENTED();
	DCHECK_EQ(net_request_.get(), request);
	request->Cancel();
	}

	void URLLoaderImpl::OnResponseStarted(net::URLRequest* request, int net_error) {
	DCHECK_EQ(net_request_.get(), request);
	net_error_ = net_error;

	// Return early if the request failed.
	if (net_error_ != net::OK) {
	std::move(done_callback_)(BuildResponse(net_error_));
	return;
	}

	// In stream mode, call the callback now and write to the socket.
	if (response_body_mode_ == oldhttp::ResponseBodyMode::STREAM \|\|
	response_body_mode_ == oldhttp::ResponseBodyMode::BUFFER_OR_STREAM) {
	zx::socket read_socket;
	zx_status_t result = zx::socket::create(0, &read_socket, &write_socket_);
	if (result != ZX_OK) {
	ZX_DLOG(WARNING, result) << "zx_socket_create";
	std::move(done_callback_)(BuildResponse(net::ERR_INSUFFICIENT_RESOURCES));
	return;
	}
	oldhttp::URLResponse response = BuildResponse(net::OK);
	response.body = oldhttp::URLBody::New();
	response.body->set_stream(std::move(read_socket));
	std::move(done_callback_)(std::move(response));
	}

	// In stream mode, the buffer is used as a temporary buffer to write to the
	// socket. In buffer mode, it is expanded as more of the response is read.
	buffer_->SetCapacity(kReadCapacity);

	ReadNextBuffer();
	}

	void URLLoaderImpl::OnReadCompleted(net::URLRequest* request, int bytes_read) {
	DCHECK_EQ(net_request_.get(), request);
	if (WriteResponseBytes(bytes_read)) {
	ReadNextBuffer();
	}
	}

	void URLLoaderImpl::OnZxHandleSignalled(zx_handle_t handle,
	zx_signals_t signals) {
	// We should never have to process signals we didn't ask for.
	DCHECK((ZX_CHANNEL_WRITABLE \| ZX_CHANNEL_PEER_CLOSED) & signals);
	DCHECK_GT(buffered_bytes_, 0);

	if (signals & ZX_CHANNEL_PEER_CLOSED) {
	return;
	}

	if (WriteResponseBytes(buffered_bytes_))
	ReadNextBuffer();
	buffered_bytes_ = 0;
	}

	void URLLoaderImpl::ReadNextBuffer() {
	int net_result;
	do {
	net_result = net_request_->Read(buffer_.get(), kReadCapacity);
	if (net_result == net::ERR_IO_PENDING) {
	return;
	}
	} while (WriteResponseBytes(net_result));
	}

	bool URLLoaderImpl::WriteResponseBytes(int result) {
	if (result < 0) {
	// Signal read error back to the client.
	if (write_socket_) {
	DCHECK(response_body_mode_ == oldhttp::ResponseBodyMode::STREAM \|\|
	response_body_mode_ ==
	oldhttp::ResponseBodyMode::BUFFER_OR_STREAM);
	// There is no need to check the return value of this call as there is no
	// way to recover from a failed socket close.
	write_socket_ = zx::socket();
	} else {
	DCHECK_EQ(response_body_mode_, oldhttp::ResponseBodyMode::BUFFER);
	std::move(done_callback_)(BuildResponse(result));
	}
	return false;
	}

	if (result == 0) {
	// Read complete.
	if (write_socket_) {
	DCHECK(response_body_mode_ == oldhttp::ResponseBodyMode::STREAM \|\|
	response_body_mode_ ==
	oldhttp::ResponseBodyMode::BUFFER_OR_STREAM);
	// In socket mode, attempt to shut down the socket and close it.
	write_socket_.shutdown(ZX_SOCKET_SHUTDOWN_WRITE);
	write_socket_ = zx::socket();
	} else {
	DCHECK_EQ(response_body_mode_, oldhttp::ResponseBodyMode::BUFFER);
	// In buffer mode, build the response and call the callback.
	oldhttp::URLBodyPtr body = CreateURLBodyFromBuffer(buffer_.get());
	if (body) {
	oldhttp::URLResponse response = BuildResponse(net::OK);
	response.body = std::move(body);
	std::move(done_callback_)(std::move(response));
	} else {
	std::move(done_callback_)(
	BuildResponse(net::ERR_INSUFFICIENT_RESOURCES));
	}
	}
	return false;
	}

	// Write data to the response buffer or socket.
	if (write_socket_) {
	DCHECK(response_body_mode_ == oldhttp::ResponseBodyMode::STREAM \|\|
	response_body_mode_ == oldhttp::ResponseBodyMode::BUFFER_OR_STREAM);
	// In socket mode, attempt to write to the socket.
	zx_status_t status =
	write_socket_.write(0, buffer_->data(), result, nullptr);
	if (status == ZX_ERR_SHOULD_WAIT) {
	// Wait until the socket is writable again.
	buffered_bytes_ = result;
	base::MessageLoopCurrentForIO::Get()->WatchZxHandle(
	write_socket_.get(), false /* persistent */,
	ZX_SOCKET_WRITABLE \| ZX_SOCKET_PEER_CLOSED, &write_watch_, this);
	return false;
	}
	if (status != ZX_OK) {
	// Something went wrong, attempt to shut down the socket and close it.
	ZX_DLOG(WARNING, status) << "zx_socket_write";
	write_socket_ = zx::socket();
	return false;
	}
	} else {
	DCHECK_EQ(response_body_mode_, oldhttp::ResponseBodyMode::BUFFER);
	// In buffer mode, expand the buffer.
	buffer_->SetCapacity(buffer_->capacity() + result);
	buffer_->set_offset(buffer_->offset() + result);
	}

	return true;
	}

	oldhttp::URLResponse URLLoaderImpl::BuildResponse(int net_error) {
	oldhttp::URLResponse response;

	response.error = BuildError(net_error);
	if (response.error) {
	return response;
	}

	if (net_request_->url().is_valid()) {
	response.url = net_request_->url().spec();
	}
	response.status_code = net_request_->GetResponseCode();

	net::HttpResponseHeaders* response_headers = net_request_->response_headers();
	if (response_headers) {
	response.status_line = response_headers->GetStatusLine();
	std::string mime_type;
	if (response_headers->GetMimeType(&mime_type)) {
	response.mime_type = mime_type;
	}
	std::string charset;
	if (response_headers->GetCharset(&charset)) {
	response.charset = charset;
	}

	size_t iter = 0;
	std::string header_name;
	std::string header_value;
	response.headers.emplace();
	while (response_headers->EnumerateHeaderLines(&iter, &header_name,
	&header_value)) {
	oldhttp::HttpHeader header;
	header.name = header_name;
	header.value = header_value;
	response.headers->push_back(header);
	}
	}

	return response;
	}