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// Copyright 2020 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "remoting/base/protobuf_http_stream_parser.h"
#include <string.h>
#include "base/logging.h"
#include "net/base/io_buffer.h"
#include "remoting/base/protobuf_http_client_messages.pb.h"
#include "remoting/base/protobuf_http_status.h"
#include "third_party/protobuf/src/google/protobuf/io/coded_stream.h"
#include "third_party/protobuf/src/google/protobuf/wire_format_lite.h"
namespace remoting {
namespace {
using ::google::protobuf::internal::WireFormatLite;
constexpr int kReadBufferSpareCapacity = 512;
} // namespace
ProtobufHttpStreamParser::ProtobufHttpStreamParser(
const MessageCallback& message_callback,
StreamClosedCallback stream_closed_callback)
: message_callback_(message_callback),
stream_closed_callback_(std::move(stream_closed_callback)) {
DCHECK(message_callback_);
DCHECK(stream_closed_callback_);
}
ProtobufHttpStreamParser::~ProtobufHttpStreamParser() = default;
void ProtobufHttpStreamParser::Append(base::StringPiece data) {
int required_remaining_capacity = data.size() + kReadBufferSpareCapacity;
if (!read_buffer_) {
read_buffer_ = base::MakeRefCounted<net::GrowableIOBuffer>();
read_buffer_->SetCapacity(required_remaining_capacity);
} else if (read_buffer_->RemainingCapacity() < required_remaining_capacity) {
read_buffer_->SetCapacity(read_buffer_->offset() +
required_remaining_capacity);
}
DCHECK_GE(read_buffer_->RemainingCapacity(), static_cast<int>(data.size()));
memcpy(read_buffer_->data(), data.data(), data.size());
read_buffer_->set_offset(read_buffer_->offset() + data.size());
ParseStreamIfAvailable();
}
bool ProtobufHttpStreamParser::HasPendingData() const {
return read_buffer_ && read_buffer_->offset() > 0;
}
void ProtobufHttpStreamParser::ParseStreamIfAvailable() {
DCHECK(read_buffer_);
google::protobuf::io::CodedInputStream input_stream(
reinterpret_cast<const uint8_t*>(read_buffer_->StartOfBuffer()),
read_buffer_->offset());
int bytes_consumed = 0;
auto weak_this = weak_factory_.GetWeakPtr();
// We can't use StreamBody::ParseFromString() here, as it can't do partial
// parsing, nor can it tell how many bytes are consumed.
while (bytes_consumed < read_buffer_->offset()) {
bool is_successful = ParseOneField(&input_stream);
if (!weak_this) {
// The callback might have deleted |this|, in which case we need to
// carefully return without touching any member of |this|.
return;
}
if (is_successful) {
// Only update |bytes_consumed| if the whole field is decoded.
// |input_stream| can still advance when the field is not decodable.
bytes_consumed = input_stream.CurrentPosition();
} else {
// The stream data can't be fully decoded yet.
break;
}
}
if (bytes_consumed == 0) {
return;
}
CHECK_LE(bytes_consumed, read_buffer_->offset());
int bytes_not_consumed = read_buffer_->offset() - bytes_consumed;
memmove(read_buffer_->StartOfBuffer(),
read_buffer_->StartOfBuffer() + bytes_consumed, bytes_not_consumed);
read_buffer_->set_offset(bytes_not_consumed);
}
bool ProtobufHttpStreamParser::ParseOneField(
google::protobuf::io::CodedInputStream* input_stream) {
// Note that the StreamBody definition is only significant in its tag ID
// allocations for "messages" and "status". There isn't any clear boundary
// between two StreamBody instances.
//
// A typical stream looks like:
//
// [message tag] <length> <message> [message tag] <length> <message> ...
// [status tag] <status> EOF
//
// Stream data failing to comply with this format usually means more data is
// needed.
uint32_t message_tag = input_stream->ReadTag();
if (message_tag == 0) {
VLOG(1) << "Can't read message tag yet.";
return false;
}
WireFormatLite::WireType wire_type =
WireFormatLite::GetTagWireType(message_tag);
int field_number = WireFormatLite::GetTagFieldNumber(message_tag);
switch (field_number) {
case protobufhttpclient::StreamBody::kMessagesFieldNumber: {
DCHECK_EQ(WireFormatLite::WireType::WIRETYPE_LENGTH_DELIMITED, wire_type);
std::string message;
if (!WireFormatLite::ReadBytes(input_stream, &message)) {
VLOG(1) << "Can't read stream message yet.";
return false;
}
VLOG(1) << "Stream message decoded.";
message_callback_.Run(message);
break;
}
case protobufhttpclient::StreamBody::kStatusFieldNumber: {
DCHECK_EQ(WireFormatLite::WireType::WIRETYPE_LENGTH_DELIMITED, wire_type);
protobufhttpclient::Status status;
if (!WireFormatLite::ReadMessage(input_stream, &status)) {
VLOG(1) << "Can't read status yet.";
return false;
}
VLOG(1) << "Client status decoded.";
std::move(stream_closed_callback_).Run(ProtobufHttpStatus(status));
break;
}
default:
if (field_number == protobufhttpclient::StreamBody::kNoopFieldNumber) {
VLOG(1) << "Found noop field.";
} else {
LOG(WARNING) << "Skipping unrecognized StreamBody field: "
<< field_number
<< ", wire type: " << static_cast<int>(wire_type);
}
if (!WireFormatLite::SkipField(input_stream, message_tag)) {
VLOG(1) << "Can't skip the field yet.";
return false;
}
break;
}
return true;
}
} // namespace remoting
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