NONE,

DEFLATE,

INFLATE,

GZIP,

GUNZIP,

DEFLATERAW,

INFLATERAW,

UNZIP

public:

ZCtx(Environment* env, Local<Object> wrap, node_zlib_mode mode)

: AsyncWrap(env, wrap, AsyncWrap::PROVIDER_ZLIB),

dictionary_(nullptr),

dictionary_len_(0),

err_(0),

flush_(0),

init_done_(false),

level_(0),

memLevel_(0),

mode_(mode),

strategy_(0),

windowBits_(0),

write_in_progress_(false),

pending_close_(false),

refs_(0),

gzip_id_bytes_read_(0) {

MakeWeak<ZCtx>(this);

Wrap(wrap, this);

}

~ZCtx() override {

CHECK_EQ(false, write_in_progress_ && "write in progress");

Close();

}

void Close() {

if (write_in_progress_) {

pending_close_ = true;

return;

}

pending_close_ = false;

CHECK(init_done_ && "close before init");

CHECK_LE(mode_, UNZIP);

if (mode_ == DEFLATE || mode_ == GZIP || mode_ == DEFLATERAW) {

(void)deflateEnd(&strm_);

int64_t change_in_bytes = -static_cast<int64_t>(kDeflateContextSize);

env()->isolate()->AdjustAmountOfExternalAllocatedMemory(change_in_bytes);

} else if (mode_ == INFLATE || mode_ == GUNZIP || mode_ == INFLATERAW ||

mode_ == UNZIP) {

(void)inflateEnd(&strm_);

int64_t change_in_bytes = -static_cast<int64_t>(kInflateContextSize);

env()->isolate()->AdjustAmountOfExternalAllocatedMemory(change_in_bytes);

}

mode_ = NONE;

if (dictionary_ != nullptr) {

delete[] dictionary_;

dictionary_ = nullptr;

}

}

static void Close(const FunctionCallbackInfo<Value>& args) {

ZCtx* ctx;

ASSIGN_OR_RETURN_UNWRAP(&ctx, args.Holder());

ctx->Close();

}

// write(flush, in, in_off, in_len, out, out_off, out_len)

template <bool async>

static void Write(const FunctionCallbackInfo<Value>& args) {

CHECK_EQ(args.Length(), 7);

ZCtx* ctx;

ASSIGN_OR_RETURN_UNWRAP(&ctx, args.Holder());

CHECK(ctx->init_done_ && "write before init");

CHECK(ctx->mode_ != NONE && "already finalized");

CHECK_EQ(false, ctx->write_in_progress_ && "write already in progress");

CHECK_EQ(false, ctx->pending_close_ && "close is pending");

ctx->write_in_progress_ = true;

ctx->Ref();

CHECK_EQ(false, args[0]->IsUndefined() && "must provide flush value");

unsigned int flush = args[0]->Uint32Value();

if (flush != Z_NO_FLUSH &&

flush != Z_PARTIAL_FLUSH &&

flush != Z_SYNC_FLUSH &&

flush != Z_FULL_FLUSH &&

flush != Z_FINISH &&

flush != Z_BLOCK) {

CHECK(0 && "Invalid flush value");

}

Bytef *in;

Bytef *out;

size_t in_off, in_len, out_off, out_len;

Environment* env = ctx->env();

if (args[1]->IsNull()) {

// just a flush

in = nullptr;

in_len = 0;

in_off = 0;

} else {

CHECK(Buffer::HasInstance(args[1]));

Local<Object> in_buf;

in_buf = args[1]->ToObject(env->isolate());

in_off = args[2]->Uint32Value();

in_len = args[3]->Uint32Value();

CHECK(Buffer::IsWithinBounds(in_off, in_len, Buffer::Length(in_buf)));

in = reinterpret_cast<Bytef *>(Buffer::Data(in_buf) + in_off);

}

CHECK(Buffer::HasInstance(args[4]));

Local<Object> out_buf = args[4]->ToObject(env->isolate());

out_off = args[5]->Uint32Value();

out_len = args[6]->Uint32Value();

CHECK(Buffer::IsWithinBounds(out_off, out_len, Buffer::Length(out_buf)));

out = reinterpret_cast<Bytef *>(Buffer::Data(out_buf) + out_off);

// build up the work request

uv_work_t* work_req = &(ctx->work_req_);

ctx->strm_.avail_in = in_len;

ctx->strm_.next_in = in;

ctx->strm_.avail_out = out_len;

ctx->strm_.next_out = out;

ctx->flush_ = flush;

if (!async) {

// sync version

ctx->env()->PrintSyncTrace();

Process(work_req);

if (CheckError(ctx))

AfterSync(ctx, args);

return;

}

// async version

uv_queue_work(ctx->env()->event_loop(),

work_req,

ZCtx::Process,

ZCtx::After);

args.GetReturnValue().Set(ctx->object());

}

static void AfterSync(ZCtx* ctx, const FunctionCallbackInfo<Value>& args) {

Environment* env = ctx->env();

Local<Integer> avail_out = Integer::New(env->isolate(),

ctx->strm_.avail_out);

Local<Integer> avail_in = Integer::New(env->isolate(),

ctx->strm_.avail_in);

ctx->write_in_progress_ = false;

Local<Array> result = Array::New(env->isolate(), 2);

result->Set(0, avail_in);

result->Set(1, avail_out);

args.GetReturnValue().Set(result);

ctx->Unref();

}

// thread pool!

// This function may be called multiple times on the uv_work pool

// for a single write() call, until all of the input bytes have

// been consumed.

static void Process(uv_work_t* work_req) {

ZCtx *ctx = ContainerOf(&ZCtx::work_req_, work_req);

const Bytef* next_expected_header_byte = nullptr;

// If the avail_out is left at 0, then it means that it ran out

// of room. If there was avail_out left over, then it means

// that all of the input was consumed.

switch (ctx->mode_) {

case DEFLATE:

case GZIP:

case DEFLATERAW:

ctx->err_ = deflate(&ctx->strm_, ctx->flush_);

break;

case UNZIP:

if (ctx->strm_.avail_in > 0) {

next_expected_header_byte = ctx->strm_.next_in;

}

switch (ctx->gzip_id_bytes_read_) {

case 0:

if (next_expected_header_byte == nullptr) {

break;

}

if (*next_expected_header_byte == GZIP_HEADER_ID1) {

ctx->gzip_id_bytes_read_ = 1;

next_expected_header_byte++;

if (ctx->strm_.avail_in == 1) {

// The only available byte was already read.

break;

}

} else {

ctx->mode_ = INFLATE;

break;

}

// fallthrough

case 1:

if (next_expected_header_byte == nullptr) {

break;

}

if (*next_expected_header_byte == GZIP_HEADER_ID2) {

ctx->gzip_id_bytes_read_ = 2;

ctx->mode_ = GUNZIP;

} else {

// There is no actual difference between INFLATE and INFLATERAW

// (after initialization).

ctx->mode_ = INFLATE;

}

break;

default:

CHECK(0 && "invalid number of gzip magic number bytes read");

}

// fallthrough

case INFLATE:

case GUNZIP:

case INFLATERAW:

ctx->err_ = inflate(&ctx->strm_, ctx->flush_);

// If data was encoded with dictionary (INFLATERAW will have it set in

// SetDictionary, don't repeat that here)

if (ctx->mode_ != INFLATERAW &&

ctx->err_ == Z_NEED_DICT &&

ctx->dictionary_ != nullptr) {

// Load it

ctx->err_ = inflateSetDictionary(&ctx->strm_,

ctx->dictionary_,

ctx->dictionary_len_);

if (ctx->err_ == Z_OK) {

// And try to decode again

ctx->err_ = inflate(&ctx->strm_, ctx->flush_);

} else if (ctx->err_ == Z_DATA_ERROR) {

// Both inflateSetDictionary() and inflate() return Z_DATA_ERROR.

// Make it possible for After() to tell a bad dictionary from bad

// input.

ctx->err_ = Z_NEED_DICT;

}

}

while (ctx->strm_.avail_in > 0 &&

ctx->mode_ == GUNZIP &&

ctx->err_ == Z_STREAM_END &&

ctx->strm_.next_in[0] != 0x00) {

// Bytes remain in input buffer. Perhaps this is another compressed

// member in the same archive, or just trailing garbage.

// Trailing zero bytes are okay, though, since they are frequently

// used for padding.

Reset(ctx);

ctx->err_ = inflate(&ctx->strm_, ctx->flush_);

}

break;

default:

UNREACHABLE();

}

// pass any errors back to the main thread to deal with.

// now After will emit the output, and

// either schedule another call to Process,

// or shift the queue and call Process.

}

static bool CheckError(ZCtx* ctx) {

// Acceptable error states depend on the type of zlib stream.

switch (ctx->err_) {

case Z_OK:

case Z_BUF_ERROR:

if (ctx->strm_.avail_out != 0 && ctx->flush_ == Z_FINISH) {

ZCtx::Error(ctx, "unexpected end of file");

return false;

}

case Z_STREAM_END:

// normal statuses, not fatal

break;

case Z_NEED_DICT:

if (ctx->dictionary_ == nullptr)

ZCtx::Error(ctx, "Missing dictionary");

else

ZCtx::Error(ctx, "Bad dictionary");

return false;

default:

// something else.

ZCtx::Error(ctx, "Zlib error");

return false;

}

return true;

}

// v8 land!

static void After(uv_work_t* work_req, int status) {

CHECK_EQ(status, 0);

ZCtx* ctx = ContainerOf(&ZCtx::work_req_, work_req);

Environment* env = ctx->env();

HandleScope handle_scope(env->isolate());

Context::Scope context_scope(env->context());

if (!CheckError(ctx))

return;

Local<Integer> avail_out = Integer::New(env->isolate(),

ctx->strm_.avail_out);

Local<Integer> avail_in = Integer::New(env->isolate(),

ctx->strm_.avail_in);

ctx->write_in_progress_ = false;

// call the write() cb

Local<Value> args[2] = { avail_in, avail_out };

ctx->MakeCallback(env->callback_string(), arraysize(args), args);

ctx->Unref();

if (ctx->pending_close_)

ctx->Close();

}

static void Error(ZCtx* ctx, const char* message) {

Environment* env = ctx->env();

// If you hit this assertion, you forgot to enter the v8::Context first.

CHECK_EQ(env->context(), env->isolate()->GetCurrentContext());

if (ctx->strm_.msg != nullptr) {

message = ctx->strm_.msg;

}

HandleScope scope(env->isolate());

Local<Value> args[2] = {

OneByteString(env->isolate(), message),

Number::New(env->isolate(), ctx->err_)

};

ctx->MakeCallback(env->onerror_string(), arraysize(args), args);

// no hope of rescue.

if (ctx->write_in_progress_)

ctx->Unref();

ctx->write_in_progress_ = false;

if (ctx->pending_close_)

ctx->Close();

}

static void New(const FunctionCallbackInfo<Value>& args) {

Environment* env = Environment::GetCurrent(args);

if (args.Length() < 1 || !args[0]->IsInt32()) {

return env->ThrowTypeError("Bad argument");

}

node_zlib_mode mode = static_cast<node_zlib_mode>(args[0]->Int32Value());

if (mode < DEFLATE || mode > UNZIP) {

return env->ThrowTypeError("Bad argument");

}

new ZCtx(env, args.This(), mode);

}

// just pull the ints out of the args and call the other Init

static void Init(const FunctionCallbackInfo<Value>& args) {

CHECK((args.Length() == 4 || args.Length() == 5) &&

"init(windowBits, level, memLevel, strategy, [dictionary])");

ZCtx* ctx;

ASSIGN_OR_RETURN_UNWRAP(&ctx, args.Holder());

int windowBits = args[0]->Uint32Value();

CHECK((windowBits >= 8 && windowBits <= 15) && "invalid windowBits");

int level = args[1]->Int32Value();

CHECK((level >= -1 && level <= 9) && "invalid compression level");

int memLevel = args[2]->Uint32Value();

CHECK((memLevel >= 1 && memLevel <= 9) && "invalid memlevel");

int strategy = args[3]->Uint32Value();

CHECK((strategy == Z_FILTERED ||

strategy == Z_HUFFMAN_ONLY ||

strategy == Z_RLE ||

strategy == Z_FIXED ||

strategy == Z_DEFAULT_STRATEGY) && "invalid strategy");

char* dictionary = nullptr;

size_t dictionary_len = 0;

if (args.Length() >= 5 && Buffer::HasInstance(args[4])) {

Local<Object> dictionary_ = args[4]->ToObject(args.GetIsolate());

dictionary_len = Buffer::Length(dictionary_);

dictionary = new char[dictionary_len];

memcpy(dictionary, Buffer::Data(dictionary_), dictionary_len);

}

Init(ctx, level, windowBits, memLevel, strategy,

dictionary, dictionary_len);

SetDictionary(ctx);

}

static void Params(const FunctionCallbackInfo<Value>& args) {

CHECK(args.Length() == 2 && "params(level, strategy)");

ZCtx* ctx;

ASSIGN_OR_RETURN_UNWRAP(&ctx, args.Holder());

Params(ctx, args[0]->Int32Value(), args[1]->Int32Value());

}

static void Reset(const FunctionCallbackInfo<Value> &args) {

ZCtx* ctx;

ASSIGN_OR_RETURN_UNWRAP(&ctx, args.Holder());

Reset(ctx);

SetDictionary(ctx);

}

static void Init(ZCtx *ctx, int level, int windowBits, int memLevel,

int strategy, char* dictionary, size_t dictionary_len) {

ctx->level_ = level;

ctx->windowBits_ = windowBits;

ctx->memLevel_ = memLevel;

ctx->strategy_ = strategy;

ctx->strm_.zalloc = Z_NULL;

ctx->strm_.zfree = Z_NULL;

ctx->strm_.opaque = Z_NULL;

ctx->flush_ = Z_NO_FLUSH;

ctx->err_ = Z_OK;

if (ctx->mode_ == GZIP || ctx->mode_ == GUNZIP) {

ctx->windowBits_ += 16;

}

if (ctx->mode_ == UNZIP) {

ctx->windowBits_ += 32;

}

if (ctx->mode_ == DEFLATERAW || ctx->mode_ == INFLATERAW) {

ctx->windowBits_ *= -1;

}

switch (ctx->mode_) {

case DEFLATE:

case GZIP:

case DEFLATERAW:

ctx->err_ = deflateInit2(&ctx->strm_,

ctx->level_,

Z_DEFLATED,

ctx->windowBits_,

ctx->memLevel_,

ctx->strategy_);

ctx->env()->isolate()

->AdjustAmountOfExternalAllocatedMemory(kDeflateContextSize);

break;

case INFLATE:

case GUNZIP:

case INFLATERAW:

case UNZIP:

ctx->err_ = inflateInit2(&ctx->strm_, ctx->windowBits_);

ctx->env()->isolate()

->AdjustAmountOfExternalAllocatedMemory(kInflateContextSize);

break;

default:

UNREACHABLE();

}

ctx->dictionary_ = reinterpret_cast<Bytef *>(dictionary);

ctx->dictionary_len_ = dictionary_len;

ctx->write_in_progress_ = false;

ctx->init_done_ = true;

if (ctx->err_ != Z_OK) {

if (dictionary != nullptr) {

delete[] dictionary;

ctx->dictionary_ = nullptr;

}

ctx->mode_ = NONE;

ctx->env()->ThrowError("Init error");

}

}

static void SetDictionary(ZCtx* ctx) {

if (ctx->dictionary_ == nullptr)

return;

ctx->err_ = Z_OK;

switch (ctx->mode_) {

case DEFLATE:

case DEFLATERAW:

ctx->err_ = deflateSetDictionary(&ctx->strm_,

ctx->dictionary_,

ctx->dictionary_len_);

break;

case INFLATERAW:

// The other inflate cases will have the dictionary set when inflate()

// returns Z_NEED_DICT in Process()

ctx->err_ = inflateSetDictionary(&ctx->strm_,

ctx->dictionary_,

ctx->dictionary_len_);

break;

default:

break;

}

if (ctx->err_ != Z_OK) {

ZCtx::Error(ctx, "Failed to set dictionary");

}

}

static void Params(ZCtx* ctx, int level, int strategy) {

ctx->err_ = Z_OK;

switch (ctx->mode_) {

case DEFLATE:

case DEFLATERAW:

ctx->err_ = deflateParams(&ctx->strm_, level, strategy);

break;

default:

break;

}

if (ctx->err_ != Z_OK && ctx->err_ != Z_BUF_ERROR) {

ZCtx::Error(ctx, "Failed to set parameters");

}

}

static void Reset(ZCtx* ctx) {

ctx->err_ = Z_OK;

switch (ctx->mode_) {

case DEFLATE:

case DEFLATERAW:

case GZIP:

ctx->err_ = deflateReset(&ctx->strm_);

break;

case INFLATE:

case INFLATERAW:

case GUNZIP:

ctx->err_ = inflateReset(&ctx->strm_);

break;

default:

break;

}

if (ctx->err_ != Z_OK) {

ZCtx::Error(ctx, "Failed to reset stream");

}

}

size_t self_size() const override { return sizeof(*this); }

private:

void Ref() {

if (++refs_ == 1) {

ClearWeak();

}

}

void Unref() {

CHECK_GT(refs_, 0);

if (--refs_ == 0) {

MakeWeak<ZCtx>(this);

}

}

static const int kDeflateContextSize = 16384; // approximate

static const int kInflateContextSize = 10240; // approximate

Bytef* dictionary_;

size_t dictionary_len_;

int err_;

int flush_;

bool init_done_;

int level_;

int memLevel_;

node_zlib_mode mode_;

int strategy_;

z_stream strm_;

int windowBits_;

uv_work_t work_req_;

bool write_in_progress_;

bool pending_close_;

unsigned int refs_;

unsigned int gzip_id_bytes_read_;

Local<Value> unused,

Local<Context> context,

void* priv) {

Environment* env = Environment::GetCurrent(context);

Local<FunctionTemplate> z = env->NewFunctionTemplate(ZCtx::New);

z->InstanceTemplate()->SetInternalFieldCount(1);

AsyncWrap::AddWrapMethods(env, z);

env->SetProtoMethod(z, "write", ZCtx::Write<true>);

env->SetProtoMethod(z, "writeSync", ZCtx::Write<false>);

env->SetProtoMethod(z, "init", ZCtx::Init);

env->SetProtoMethod(z, "close", ZCtx::Close);

env->SetProtoMethod(z, "params", ZCtx::Params);

env->SetProtoMethod(z, "reset", ZCtx::Reset);

Local<String> zlibString = FIXED_ONE_BYTE_STRING(env->isolate(), "Zlib");

z->SetClassName(zlibString);

target->Set(zlibString, z->GetFunction());

target->Set(FIXED_ONE_BYTE_STRING(env->isolate(), "ZLIB_VERSION"),

FIXED_ONE_BYTE_STRING(env->isolate(), ZLIB_VERSION));