// Copyright (c) 2009 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 "base/scoped_ptr.h"
#include "base/stats_counters.h"
#include "flip_framer.h" // cross-google3 directory naming.
#include "flip_frame_builder.h"
#include "flip_bitmasks.h"
#if defined(USE_SYSTEM_ZLIB)
#include <zlib.h>
#else
#include "third_party/zlib/zlib.h"
#endif
namespace flip {
// The initial size of the control frame buffer; this is used internally
// as we parse through control frames.
static const size_t kControlFrameBufferInitialSize = 32 * 1024;
// The maximum size of the control frame buffer that we support.
// TODO(mbelshe): We should make this stream-based so there are no limits.
static const size_t kControlFrameBufferMaxSize = 64 * 1024;
// By default is compression on or off.
bool FlipFramer::compression_default_ = true;
#ifdef DEBUG_FLIP_STATE_CHANGES
#define CHANGE_STATE(newstate) \
{ \
do { \
LOG(INFO) << "Changing state from: " \
<< StateToString(state_) \
<< " to " << StateToString(newstate) << "\n"; \
state_ = newstate; \
} while (false); \
}
#else
#define CHANGE_STATE(newstate) (state_ = newstate)
#endif
FlipFramer::FlipFramer()
: state_(FLIP_RESET),
error_code_(FLIP_NO_ERROR),
remaining_payload_(0),
remaining_control_payload_(0),
current_frame_buffer_(NULL),
current_frame_len_(0),
current_frame_capacity_(0),
enable_compression_(compression_default_),
visitor_(NULL) {
}
FlipFramer::~FlipFramer() {
if (compressor_.get()) {
deflateEnd(compressor_.get());
}
if (decompressor_.get()) {
inflateEnd(decompressor_.get());
}
delete [] current_frame_buffer_;
}
void FlipFramer::Reset() {
state_ = FLIP_RESET;
error_code_ = FLIP_NO_ERROR;
remaining_payload_ = 0;
remaining_control_payload_ = 0;
current_frame_len_ = 0;
if (current_frame_capacity_ != kControlFrameBufferInitialSize) {
delete [] current_frame_buffer_;
current_frame_buffer_ = 0;
current_frame_capacity_ = 0;
ExpandControlFrameBuffer(kControlFrameBufferInitialSize);
}
}
const char* FlipFramer::StateToString(int state) {
switch (state) {
case FLIP_ERROR:
return "ERROR";
case FLIP_DONE:
return "DONE";
case FLIP_AUTO_RESET:
return "AUTO_RESET";
case FLIP_RESET:
return "RESET";
case FLIP_READING_COMMON_HEADER:
return "READING_COMMON_HEADER";
case FLIP_INTERPRET_CONTROL_FRAME_COMMON_HEADER:
return "INTERPRET_CONTROL_FRAME_COMMON_HEADER";
case FLIP_CONTROL_FRAME_PAYLOAD:
return "CONTROL_FRAME_PAYLOAD";
case FLIP_IGNORE_REMAINING_PAYLOAD:
return "IGNORE_REMAINING_PAYLOAD";
case FLIP_FORWARD_STREAM_FRAME:
return "FORWARD_STREAM_FRAME";
}
return "UNKNOWN_STATE";
}
size_t FlipFramer::BytesSafeToRead() const {
switch (state_) {
case FLIP_ERROR:
case FLIP_DONE:
case FLIP_AUTO_RESET:
case FLIP_RESET:
return 0;
case FLIP_READING_COMMON_HEADER:
DCHECK(current_frame_len_ < FlipFrame::size());
return FlipFrame::size() - current_frame_len_;
case FLIP_INTERPRET_CONTROL_FRAME_COMMON_HEADER:
return 0;
case FLIP_CONTROL_FRAME_PAYLOAD:
case FLIP_IGNORE_REMAINING_PAYLOAD:
case FLIP_FORWARD_STREAM_FRAME:
return remaining_payload_;
}
// We should never get to here.
return 0;
}
void FlipFramer::set_error(FlipError error) {
DCHECK(visitor_);
error_code_ = error;
CHANGE_STATE(FLIP_ERROR);
visitor_->OnError(this);
}
const char* FlipFramer::ErrorCodeToString(int error_code) {
switch (error_code) {
case FLIP_NO_ERROR:
return "NO_ERROR";
case FLIP_UNKNOWN_CONTROL_TYPE:
return "UNKNOWN_CONTROL_TYPE";
case FLIP_INVALID_CONTROL_FRAME:
return "INVALID_CONTROL_FRAME";
case FLIP_CONTROL_PAYLOAD_TOO_LARGE:
return "CONTROL_PAYLOAD_TOO_LARGE";
case FLIP_ZLIB_INIT_FAILURE:
return "ZLIB_INIT_FAILURE";
case FLIP_UNSUPPORTED_VERSION:
return "UNSUPPORTED_VERSION";
case FLIP_DECOMPRESS_FAILURE:
return "DECOMPRESS_FAILURE";
}
return "UNKNOWN_STATE";
}
size_t FlipFramer::ProcessInput(const char* data, size_t len) {
DCHECK(visitor_);
DCHECK(data);
size_t original_len = len;
while (len != 0) {
switch (state_) {
case FLIP_ERROR:
case FLIP_DONE:
goto bottom;
case FLIP_AUTO_RESET:
case FLIP_RESET:
Reset();
CHANGE_STATE(FLIP_READING_COMMON_HEADER);
continue;
case FLIP_READING_COMMON_HEADER: {
int bytes_read = ProcessCommonHeader(data, len);
len -= bytes_read;
data += bytes_read;
continue;
}
// Arguably, this case is not necessary, as no bytes are consumed here.
// I felt it was a nice partitioning, however (which probably indicates
// that it should be refactored into its own function!)
case FLIP_INTERPRET_CONTROL_FRAME_COMMON_HEADER:
ProcessControlFrameHeader();
continue;
case FLIP_CONTROL_FRAME_PAYLOAD: {
int bytes_read = ProcessControlFramePayload(data, len);
len -= bytes_read;
data += bytes_read;
}
// intentional fallthrough
case FLIP_IGNORE_REMAINING_PAYLOAD:
// control frame has too-large payload
// intentional fallthrough
case FLIP_FORWARD_STREAM_FRAME: {
int bytes_read = ProcessDataFramePayload(data, len);
len -= bytes_read;
data += bytes_read;
continue;
}
default:
break;
}
}
bottom:
return original_len - len;
}
size_t FlipFramer::ProcessCommonHeader(const char* data, size_t len) {
// This should only be called when we're in the FLIP_READING_COMMON_HEADER
// state.
DCHECK(state_ == FLIP_READING_COMMON_HEADER);
int original_len = len;
FlipFrame current_frame(current_frame_buffer_, false);
do {
if (current_frame_len_ < FlipFrame::size()) {
size_t bytes_desired = FlipFrame::size() - current_frame_len_;
size_t bytes_to_append = std::min(bytes_desired, len);
char* header_buffer = current_frame_buffer_;
memcpy(&header_buffer[current_frame_len_], data, bytes_to_append);
current_frame_len_ += bytes_to_append;
data += bytes_to_append;
len -= bytes_to_append;
// Check for an empty data frame.
if (current_frame_len_ == FlipFrame::size() &&
!current_frame.is_control_frame() &&
current_frame.length() == 0) {
if (current_frame.flags() & CONTROL_FLAG_FIN) {
FlipDataFrame data_frame(current_frame_buffer_, false);
visitor_->OnStreamFrameData(data_frame.stream_id(), NULL, 0);
}
CHANGE_STATE(FLIP_RESET);
}
break;
}
remaining_payload_ = current_frame.length();
// This is just a sanity check for help debugging early frame errors.
if (remaining_payload_ > 1000000u) {
LOG(ERROR) <<
"Unexpectedly large frame. Flip session is likely corrupt.";
}
// if we're here, then we have the common header all received.
if (!current_frame.is_control_frame())
CHANGE_STATE(FLIP_FORWARD_STREAM_FRAME);
else
CHANGE_STATE(FLIP_INTERPRET_CONTROL_FRAME_COMMON_HEADER);
} while (false);
return original_len - len;
}
void FlipFramer::ProcessControlFrameHeader() {
DCHECK_EQ(FLIP_NO_ERROR, error_code_);
DCHECK_LE(FlipFrame::size(), current_frame_len_);
FlipControlFrame current_control_frame(current_frame_buffer_, false);
// Do some sanity checking on the control frame sizes.
switch (current_control_frame.type()) {
case SYN_STREAM:
if (current_control_frame.length() <
FlipSynStreamControlFrame::size() - FlipControlFrame::size())
set_error(FLIP_INVALID_CONTROL_FRAME);
break;
case SYN_REPLY:
if (current_control_frame.length() <
FlipSynReplyControlFrame::size() - FlipControlFrame::size())
set_error(FLIP_INVALID_CONTROL_FRAME);
break;
case FIN_STREAM:
if (current_control_frame.length() !=
FlipFinStreamControlFrame::size() - FlipFrame::size())
set_error(FLIP_INVALID_CONTROL_FRAME);
break;
case NOOP:
// NOOP. Swallow it.
CHANGE_STATE(FLIP_AUTO_RESET);
return;
default:
set_error(FLIP_UNKNOWN_CONTROL_TYPE);
break;
}
// We only support version 1 of this protocol.
if (current_control_frame.version() != kFlipProtocolVersion)
set_error(FLIP_UNSUPPORTED_VERSION);
remaining_control_payload_ = current_control_frame.length();
if (remaining_control_payload_ > kControlFrameBufferMaxSize)
set_error(FLIP_CONTROL_PAYLOAD_TOO_LARGE);
if (error_code_)
return;
ExpandControlFrameBuffer(remaining_control_payload_);
CHANGE_STATE(FLIP_CONTROL_FRAME_PAYLOAD);
}
size_t FlipFramer::ProcessControlFramePayload(const char* data, size_t len) {
size_t original_len = len;
do {
if (remaining_control_payload_) {
size_t amount_to_consume = std::min(remaining_control_payload_, len);
memcpy(¤t_frame_buffer_[current_frame_len_], data,
amount_to_consume);
current_frame_len_ += amount_to_consume;
data += amount_to_consume;
len -= amount_to_consume;
remaining_control_payload_ -= amount_to_consume;
remaining_payload_ -= amount_to_consume;
if (remaining_control_payload_)
break;
}
FlipControlFrame control_frame(current_frame_buffer_, false);
visitor_->OnControl(&control_frame);
// If this is a FIN, tell the caller.
if (control_frame.type() == SYN_REPLY &&
control_frame.flags() & CONTROL_FLAG_FIN)
visitor_->OnStreamFrameData(control_frame.stream_id(), NULL, 0);
CHANGE_STATE(FLIP_IGNORE_REMAINING_PAYLOAD);
} while (false);
return original_len - len;
}
size_t FlipFramer::ProcessDataFramePayload(const char* data, size_t len) {
size_t original_len = len;
FlipDataFrame current_data_frame(current_frame_buffer_, false);
if (remaining_payload_) {
size_t amount_to_forward = std::min(remaining_payload_, len);
if (amount_to_forward && state_ != FLIP_IGNORE_REMAINING_PAYLOAD) {
if (current_data_frame.flags() & DATA_FLAG_COMPRESSED) {
// TODO(mbelshe): Assert that the decompressor is init'ed.
if (!InitializeDecompressor())
return NULL;
size_t decompressed_max_size = amount_to_forward * 100;
scoped_ptr<char> decompressed(new char[decompressed_max_size]);
decompressor_->next_in = reinterpret_cast<Bytef*>(
const_cast<char*>(data));
decompressor_->avail_in = amount_to_forward;
decompressor_->next_out =
reinterpret_cast<Bytef*>(decompressed.get());
decompressor_->avail_out = decompressed_max_size;
int rv = inflate(decompressor_.get(), Z_SYNC_FLUSH);
if (rv != Z_OK) {
set_error(FLIP_DECOMPRESS_FAILURE);
return 0;
}
size_t decompressed_size = decompressed_max_size -
decompressor_->avail_out;
// Only inform the visitor if there is data.
if (decompressed_size)
visitor_->OnStreamFrameData(current_data_frame.stream_id(),
decompressed.get(),
decompressed_size);
amount_to_forward -= decompressor_->avail_in;
} else {
// The data frame was not compressed.
// Only inform the visitor if there is data.
if (amount_to_forward)
visitor_->OnStreamFrameData(current_data_frame.stream_id(),
data, amount_to_forward);
}
}
data += amount_to_forward;
len -= amount_to_forward;
remaining_payload_ -= amount_to_forward;
// If the FIN flag is set, and there is no more data in this data
// frame, inform the visitor of EOF via a 0-length data frame.
if (!remaining_payload_ &&
current_data_frame.flags() & DATA_FLAG_FIN)
visitor_->OnStreamFrameData(current_data_frame.stream_id(), NULL,
0);
} else {
CHANGE_STATE(FLIP_AUTO_RESET);
}
return original_len - len;
}
void FlipFramer::ExpandControlFrameBuffer(size_t size) {
DCHECK(size < kControlFrameBufferMaxSize);
if (size < current_frame_capacity_)
return;
int alloc_size = size + FlipFrame::size();
char* new_buffer = new char[alloc_size];
memcpy(new_buffer, current_frame_buffer_, current_frame_len_);
current_frame_capacity_ = alloc_size;
current_frame_buffer_ = new_buffer;
}
bool FlipFramer::ParseHeaderBlock(const FlipFrame* frame,
FlipHeaderBlock* block) {
FlipControlFrame control_frame(frame->data(), false);
uint32 type = control_frame.type();
if (type != SYN_STREAM && type != SYN_REPLY)
return false;
// Find the header data within the control frame.
scoped_ptr<FlipFrame> decompressed_frame(DecompressFrame(frame));
if (!decompressed_frame.get())
return false;
FlipSynStreamControlFrame syn_frame(decompressed_frame->data(), false);
const char *header_data = syn_frame.header_block();
int header_length = syn_frame.header_block_len();
FlipFrameBuilder builder(header_data, header_length);
void* iter = NULL;
uint16 num_headers;
if (builder.ReadUInt16(&iter, &num_headers)) {
for (int index = 0; index < num_headers; ++index) {
std::string name;
std::string value;
if (!builder.ReadString(&iter, &name))
break;
if (!builder.ReadString(&iter, &value))
break;
if (block->find(name) == block->end()) {
(*block)[name] = value;
} else {
return false;
}
}
return true;
}
return false;
}
FlipSynStreamControlFrame* FlipFramer::CreateSynStream(
FlipStreamId stream_id, int priority, FlipControlFlags flags,
bool compressed, FlipHeaderBlock* headers) {
FlipFrameBuilder frame;
frame.WriteUInt16(kControlFlagMask | kFlipProtocolVersion);
frame.WriteUInt16(SYN_STREAM);
frame.WriteUInt32(0); // Placeholder for the length and flags
frame.WriteUInt32(stream_id);
frame.WriteUInt16(ntohs(priority) << 6); // Priority.
frame.WriteUInt16(headers->size()); // Number of headers.
FlipHeaderBlock::iterator it;
for (it = headers->begin(); it != headers->end(); ++it) {
frame.WriteString(it->first);
frame.WriteString(it->second);
}
// Write the length and flags.
size_t length = frame.length() - FlipFrame::size();
DCHECK(length < static_cast<size_t>(kLengthMask));
FlagsAndLength flags_length;
flags_length.length_ = htonl(static_cast<uint32>(length));
flags_length.flags_[0] = flags;
frame.WriteBytesToOffset(4, &flags_length, sizeof(flags_length));
scoped_ptr<FlipFrame> syn_frame(frame.take());
if (compressed) {
return reinterpret_cast<FlipSynStreamControlFrame*>(
CompressFrame(syn_frame.get()));
}
return reinterpret_cast<FlipSynStreamControlFrame*>(syn_frame.release());
}
/* static */
FlipFinStreamControlFrame* FlipFramer::CreateFinStream(FlipStreamId stream_id,
int status) {
FlipFrameBuilder frame;
frame.WriteUInt16(kControlFlagMask | kFlipProtocolVersion);
frame.WriteUInt16(FIN_STREAM);
frame.WriteUInt32(8);
frame.WriteUInt32(stream_id);
frame.WriteUInt32(status);
return reinterpret_cast<FlipFinStreamControlFrame*>(frame.take());
}
FlipSynReplyControlFrame* FlipFramer::CreateSynReply(FlipStreamId stream_id,
FlipControlFlags flags, bool compressed, FlipHeaderBlock* headers) {
FlipFrameBuilder frame;
frame.WriteUInt16(kControlFlagMask | kFlipProtocolVersion);
frame.WriteUInt16(SYN_REPLY);
frame.WriteUInt32(0); // Placeholder for the length and flags.
frame.WriteUInt32(stream_id);
frame.WriteUInt16(0); // Unused
frame.WriteUInt16(headers->size()); // Number of headers.
FlipHeaderBlock::iterator it;
for (it = headers->begin(); it != headers->end(); ++it) {
// TODO(mbelshe): Headers need to be sorted.
frame.WriteString(it->first);
frame.WriteString(it->second);
}
// Write the length
size_t length = frame.length() - FlipFrame::size();
DCHECK(length < static_cast<size_t>(kLengthMask));
FlagsAndLength flags_length;
flags_length.length_ = htonl(static_cast<uint32>(length));
flags_length.flags_[0] = flags;
frame.WriteBytesToOffset(4, &flags_length, sizeof(flags_length));
scoped_ptr<FlipFrame> reply_frame(frame.take());
if (compressed) {
return reinterpret_cast<FlipSynReplyControlFrame*>(
CompressFrame(reply_frame.get()));
}
return reinterpret_cast<FlipSynReplyControlFrame*>(reply_frame.release());
}
FlipDataFrame* FlipFramer::CreateDataFrame(FlipStreamId stream_id,
const char* data,
uint32 len, FlipDataFlags flags) {
FlipFrameBuilder frame;
frame.WriteUInt32(stream_id);
DCHECK(len < static_cast<size_t>(kLengthMask));
FlagsAndLength flags_length;
flags_length.length_ = htonl(len);
flags_length.flags_[0] = flags;
frame.WriteBytes(&flags_length, sizeof(flags_length));
frame.WriteBytes(data, len);
scoped_ptr<FlipFrame> data_frame(frame.take());
if (flags & DATA_FLAG_COMPRESSED)
return reinterpret_cast<FlipDataFrame*>(CompressFrame(data_frame.get()));
return reinterpret_cast<FlipDataFrame*>(data_frame.release());
}
/* static */
FlipControlFrame* FlipFramer::CreateNopFrame() {
FlipFrameBuilder frame;
frame.WriteUInt16(kControlFlagMask | kFlipProtocolVersion);
frame.WriteUInt16(NOOP);
frame.WriteUInt32(0);
return reinterpret_cast<FlipControlFrame*>(frame.take());
}
static const int kCompressorLevel = Z_DEFAULT_COMPRESSION;
// This is just a hacked dictionary to use for shrinking HTTP-like headers.
// TODO(mbelshe): Use a scientific methodology for computing the dictionary.
static const char dictionary[] =
"optionsgetheadpostputdeletetraceacceptaccept-charsetaccept-encodingaccept-"
"languageauthorizationexpectfromhostif-modified-sinceif-matchif-none-matchi"
"f-rangeif-unmodifiedsincemax-forwardsproxy-authorizationrangerefererteuser"
"-agent10010120020120220320420520630030130230330430530630740040140240340440"
"5406407408409410411412413414415416417500501502503504505accept-rangesageeta"
"glocationproxy-authenticatepublicretry-afterservervarywarningwww-authentic"
"ateallowcontent-basecontent-encodingcache-controlconnectiondatetrailertran"
"sfer-encodingupgradeviawarningcontent-languagecontent-lengthcontent-locati"
"oncontent-md5content-rangecontent-typeetagexpireslast-modifiedset-cookieMo"
"ndayTuesdayWednesdayThursdayFridaySaturdaySundayJanFebMarAprMayJunJulAugSe"
"pOctNovDecchunkedtext/htmlimage/pngimage/jpgimage/gifapplication/xmlapplic"
"ation/xhtmltext/plainpublicmax-agecharset=iso-8859-1utf-8gzipdeflateHTTP/1"
".1statusversionurl";
static uLong dictionary_id = 0;
bool FlipFramer::InitializeCompressor() {
if (compressor_.get())
return true; // Already initialized.
compressor_.reset(new z_stream);
memset(compressor_.get(), 0, sizeof(z_stream));
int success = deflateInit(compressor_.get(), kCompressorLevel);
if (success == Z_OK)
success = deflateSetDictionary(compressor_.get(),
reinterpret_cast<const Bytef*>(dictionary),
sizeof(dictionary));
if (success != Z_OK)
compressor_.reset(NULL);
return success == Z_OK;
}
bool FlipFramer::InitializeDecompressor() {
if (decompressor_.get())
return true; // Already initialized.
decompressor_.reset(new z_stream);
memset(decompressor_.get(), 0, sizeof(z_stream));
// Compute the id of our dictionary so that we know we're using the
// right one when asked for it.
if (dictionary_id == 0) {
dictionary_id = adler32(0L, Z_NULL, 0);
dictionary_id = adler32(dictionary_id,
reinterpret_cast<const Bytef*>(dictionary),
sizeof(dictionary));
}
int success = inflateInit(decompressor_.get());
if (success != Z_OK)
decompressor_.reset(NULL);
return success == Z_OK;
}
bool FlipFramer::GetFrameBoundaries(const FlipFrame* frame,
int* payload_length,
int* header_length,
const char** payload) const {
if (frame->is_control_frame()) {
const FlipControlFrame* control_frame =
reinterpret_cast<const FlipControlFrame*>(frame);
switch (control_frame->type()) {
case SYN_STREAM:
case SYN_REPLY:
{
const FlipSynStreamControlFrame *syn_frame =
reinterpret_cast<const FlipSynStreamControlFrame*>(frame);
*payload_length = syn_frame->header_block_len();
*header_length = syn_frame->size();
*payload = frame->data() + *header_length;
}
break;
default:
// TODO(mbelshe): set an error?
return false; // We can't compress this frame!
}
} else {
*header_length = FlipFrame::size();
*payload_length = frame->length();
*payload = frame->data() + FlipFrame::size();
}
DCHECK(static_cast<size_t>(*header_length) <=
FlipFrame::size() + *payload_length);
return true;
}
FlipFrame* FlipFramer::CompressFrame(const FlipFrame* frame) {
int payload_length;
int header_length;
const char* payload;
static StatsCounter pre_compress_bytes("flip.PreCompressSize");
static StatsCounter post_compress_bytes("flip.PostCompressSize");
if (!enable_compression_)
return DuplicateFrame(frame);
if (!GetFrameBoundaries(frame, &payload_length, &header_length, &payload))
return NULL;
if (!InitializeCompressor())
return NULL;
// TODO(mbelshe): Should we have a zlib header like what http servers do?
// Create an output frame.
int compressed_max_size = deflateBound(compressor_.get(), payload_length);
int new_frame_size = header_length + compressed_max_size;
FlipFrame* new_frame = new FlipFrame(new_frame_size);
memcpy(new_frame->data(), frame->data(), frame->length() + FlipFrame::size());
compressor_->next_in = reinterpret_cast<Bytef*>(const_cast<char*>(payload));
compressor_->avail_in = payload_length;
compressor_->next_out = reinterpret_cast<Bytef*>(new_frame->data()) +
header_length;
compressor_->avail_out = compressed_max_size;
// Data packets have a 'compressed flag
if (!new_frame->is_control_frame()) {
FlipDataFrame* data_frame = reinterpret_cast<FlipDataFrame*>(new_frame);
data_frame->set_flags(data_frame->flags() | DATA_FLAG_COMPRESSED);
}
int rv = deflate(compressor_.get(), Z_SYNC_FLUSH);
if (rv != Z_OK) { // How can we know that it compressed everything?
// This shouldn't happen, right?
delete new_frame;
return NULL;
}
int compressed_size = compressed_max_size - compressor_->avail_out;
new_frame->set_length(header_length + compressed_size - FlipFrame::size());
pre_compress_bytes.Add(payload_length);
post_compress_bytes.Add(new_frame->length());
return new_frame;
}
FlipFrame* FlipFramer::DecompressFrame(const FlipFrame* frame) {
int payload_length;
int header_length;
const char* payload;
static StatsCounter pre_decompress_bytes("flip.PreDeCompressSize");
static StatsCounter post_decompress_bytes("flip.PostDeCompressSize");
if (!enable_compression_)
return DuplicateFrame(frame);
if (!GetFrameBoundaries(frame, &payload_length, &header_length, &payload))
return NULL;
if (!frame->is_control_frame()) {
const FlipDataFrame* data_frame =
reinterpret_cast<const FlipDataFrame*>(frame);
if ((data_frame->flags() & DATA_FLAG_COMPRESSED) == 0)
return DuplicateFrame(frame);
}
if (!InitializeDecompressor())
return NULL;
// TODO(mbelshe): Should we have a zlib header like what http servers do?
// Create an output frame. Assume it does not need to be longer than
// the input data.
int decompressed_max_size = kControlFrameBufferInitialSize;
int new_frame_size = header_length + decompressed_max_size;
FlipFrame* new_frame = new FlipFrame(new_frame_size);
memcpy(new_frame->data(), frame->data(), frame->length() + FlipFrame::size());
decompressor_->next_in = reinterpret_cast<Bytef*>(const_cast<char*>(payload));
decompressor_->avail_in = payload_length;
decompressor_->next_out = reinterpret_cast<Bytef*>(new_frame->data()) +
header_length;
decompressor_->avail_out = decompressed_max_size;
int rv = inflate(decompressor_.get(), Z_SYNC_FLUSH);
if (rv == Z_NEED_DICT) {
// Need to try again with the right dictionary.
if (decompressor_->adler == dictionary_id) {
rv = inflateSetDictionary(decompressor_.get(), (const Bytef*)dictionary,
sizeof(dictionary));
if (rv == Z_OK)
rv = inflate(decompressor_.get(), Z_SYNC_FLUSH);
}
}
if (rv != Z_OK) { // How can we know that it decompressed everything?
delete new_frame;
return NULL;
}
// Unset the compressed flag for data frames.
if (!new_frame->is_control_frame()) {
FlipDataFrame* data_frame = reinterpret_cast<FlipDataFrame*>(new_frame);
data_frame->set_flags(data_frame->flags() & ~DATA_FLAG_COMPRESSED);
}
int decompressed_size = decompressed_max_size - decompressor_->avail_out;
new_frame->set_length(header_length + decompressed_size - FlipFrame::size());
pre_decompress_bytes.Add(frame->length());
post_decompress_bytes.Add(new_frame->length());
return new_frame;
}
FlipFrame* FlipFramer::DuplicateFrame(const FlipFrame* frame) {
int size = FlipFrame::size() + frame->length();
FlipFrame* new_frame = new FlipFrame(size);
memcpy(new_frame->data(), frame->data(), size);
return new_frame;
}
void FlipFramer::set_enable_compression(bool value) {
enable_compression_ = value;
}
void FlipFramer::set_enable_compression_default(bool value) {
compression_default_ = value;
}
} // namespace flip