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'use strict';
const Buffer = require('buffer').Buffer;
const internalUtil = require('internal/util');
const Transform = require('_stream_transform');
const binding = process.binding('zlib');
const assert = require('assert').ok;
const kMaxLength = require('buffer').kMaxLength;
const kRangeErrorMessage = 'Cannot create final Buffer. It would be larger ' +
`than 0x${kMaxLength.toString(16)} bytes`;
const constants = process.binding('constants').zlib;
const createClassWrapper = internalUtil.createClassWrapper;
// translation table for return codes.
const codes = {
Z_OK: constants.Z_OK,
Z_STREAM_END: constants.Z_STREAM_END,
Z_NEED_DICT: constants.Z_NEED_DICT,
Z_ERRNO: constants.Z_ERRNO,
Z_STREAM_ERROR: constants.Z_STREAM_ERROR,
Z_DATA_ERROR: constants.Z_DATA_ERROR,
Z_MEM_ERROR: constants.Z_MEM_ERROR,
Z_BUF_ERROR: constants.Z_BUF_ERROR,
Z_VERSION_ERROR: constants.Z_VERSION_ERROR
};
const ckeys = Object.keys(codes);
for (var ck = 0; ck < ckeys.length; ck++) {
var ckey = ckeys[ck];
codes[codes[ckey]] = ckey;
}
function isInvalidFlushFlag(flag) {
return typeof flag !== 'number' ||
flag < constants.Z_NO_FLUSH ||
flag > constants.Z_BLOCK;
// Covers: constants.Z_NO_FLUSH (0),
// constants.Z_PARTIAL_FLUSH (1),
// constants.Z_SYNC_FLUSH (2),
// constants.Z_FULL_FLUSH (3),
// constants.Z_FINISH (4), and
// constants.Z_BLOCK (5)
}
function isInvalidStrategy(strategy) {
return typeof strategy !== 'number' ||
strategy < constants.Z_DEFAULT_STRATEGY ||
strategy > constants.Z_FIXED;
// Covers: constants.Z_FILTERED, (1)
// constants.Z_HUFFMAN_ONLY (2),
// constants.Z_RLE (3),
// constants.Z_FIXED (4), and
// constants.Z_DEFAULT_STRATEGY (0)
}
function zlibBuffer(engine, buffer, callback) {
var buffers = [];
var nread = 0;
engine.on('error', onError);
engine.on('end', onEnd);
engine.end(buffer);
flow();
function flow() {
var chunk;
while (null !== (chunk = engine.read())) {
buffers.push(chunk);
nread += chunk.length;
}
engine.once('readable', flow);
}
function onError(err) {
engine.removeListener('end', onEnd);
engine.removeListener('readable', flow);
callback(err);
}
function onEnd() {
var buf;
var err = null;
if (nread >= kMaxLength) {
err = new RangeError(kRangeErrorMessage);
} else {
buf = Buffer.concat(buffers, nread);
}
buffers = [];
engine.close();
callback(err, buf);
}
}
function zlibBufferSync(engine, buffer) {
if (typeof buffer === 'string')
buffer = Buffer.from(buffer);
if (!(buffer instanceof Buffer))
throw new TypeError('Not a string or buffer');
var flushFlag = engine._finishFlushFlag;
return engine._processChunk(buffer, flushFlag);
}
function zlibOnError(message, errno) {
// there is no way to cleanly recover.
// continuing only obscures problems.
_close(this);
this._hadError = true;
var error = new Error(message);
error.errno = errno;
error.code = codes[errno];
this.emit('error', error);
}
function flushCallback(level, strategy, callback) {
assert(this._handle, 'zlib binding closed');
this._handle.params(level, strategy);
if (!this._hadError) {
this._level = level;
this._strategy = strategy;
if (callback) callback();
}
}
// the Zlib class they all inherit from
// This thing manages the queue of requests, and returns
// true or false if there is anything in the queue when
// you call the .write() method.
class Zlib extends Transform {
constructor(opts, mode) {
opts = opts || {};
super(opts);
this._opts = opts;
this._chunkSize = opts.chunkSize || constants.Z_DEFAULT_CHUNK;
if (opts.flush && isInvalidFlushFlag(opts.flush)) {
throw new RangeError('Invalid flush flag: ' + opts.flush);
}
if (opts.finishFlush && isInvalidFlushFlag(opts.finishFlush)) {
throw new RangeError('Invalid flush flag: ' + opts.finishFlush);
}
this._flushFlag = opts.flush || constants.Z_NO_FLUSH;
this._finishFlushFlag = opts.finishFlush !== undefined ?
opts.finishFlush : constants.Z_FINISH;
if (opts.chunkSize) {
if (opts.chunkSize < constants.Z_MIN_CHUNK) {
throw new RangeError('Invalid chunk size: ' + opts.chunkSize);
}
}
if (opts.windowBits) {
if (opts.windowBits < constants.Z_MIN_WINDOWBITS ||
opts.windowBits > constants.Z_MAX_WINDOWBITS) {
throw new RangeError('Invalid windowBits: ' + opts.windowBits);
}
}
if (opts.level) {
if (opts.level < constants.Z_MIN_LEVEL ||
opts.level > constants.Z_MAX_LEVEL) {
throw new RangeError('Invalid compression level: ' + opts.level);
}
}
if (opts.memLevel) {
if (opts.memLevel < constants.Z_MIN_MEMLEVEL ||
opts.memLevel > constants.Z_MAX_MEMLEVEL) {
throw new RangeError('Invalid memLevel: ' + opts.memLevel);
}
}
if (opts.strategy && isInvalidStrategy(opts.strategy))
throw new TypeError('Invalid strategy: ' + opts.strategy);
if (opts.dictionary) {
if (!(opts.dictionary instanceof Buffer)) {
throw new TypeError(
'Invalid dictionary: it should be a Buffer instance');
}
}
this._handle = new binding.Zlib(mode);
this._handle.onerror = zlibOnError.bind(this);
this._hadError = false;
var level = constants.Z_DEFAULT_COMPRESSION;
if (typeof opts.level === 'number') level = opts.level;
var strategy = constants.Z_DEFAULT_STRATEGY;
if (typeof opts.strategy === 'number') strategy = opts.strategy;
this._handle.init(opts.windowBits || constants.Z_DEFAULT_WINDOWBITS,
level,
opts.memLevel || constants.Z_DEFAULT_MEMLEVEL,
strategy,
opts.dictionary);
this._buffer = Buffer.allocUnsafe(this._chunkSize);
this._offset = 0;
this._level = level;
this._strategy = strategy;
this.once('end', this.close);
}
get _closed() {
return !this._handle;
}
params(level, strategy, callback) {
if (level < constants.Z_MIN_LEVEL ||
level > constants.Z_MAX_LEVEL) {
throw new RangeError('Invalid compression level: ' + level);
}
if (isInvalidStrategy(strategy))
throw new TypeError('Invalid strategy: ' + strategy);
if (this._level !== level || this._strategy !== strategy) {
this.flush(constants.Z_SYNC_FLUSH,
flushCallback.bind(this, level, strategy, callback));
} else {
process.nextTick(callback);
}
}
reset() {
assert(this._handle, 'zlib binding closed');
return this._handle.reset();
}
// This is the _flush function called by the transform class,
// internally, when the last chunk has been written.
_flush(callback) {
this._transform(Buffer.alloc(0), '', callback);
}
flush(kind, callback) {
var ws = this._writableState;
if (typeof kind === 'function' || (kind === undefined && !callback)) {
callback = kind;
kind = constants.Z_FULL_FLUSH;
}
if (ws.ended) {
if (callback)
process.nextTick(callback);
} else if (ws.ending) {
if (callback)
this.once('end', callback);
} else if (ws.needDrain) {
if (callback) {
const drainHandler = () => this.flush(kind, callback);
this.once('drain', drainHandler);
}
} else {
this._flushFlag = kind;
this.write(Buffer.alloc(0), '', callback);
}
}
close(callback) {
_close(this, callback);
process.nextTick(emitCloseNT, this);
}
_transform(chunk, encoding, cb) {
var flushFlag;
var ws = this._writableState;
var ending = ws.ending || ws.ended;
var last = ending && (!chunk || ws.length === chunk.length);
if (chunk !== null && !(chunk instanceof Buffer))
return cb(new TypeError('invalid input'));
if (!this._handle)
return cb(new Error('zlib binding closed'));
// If it's the last chunk, or a final flush, we use the Z_FINISH flush flag
// (or whatever flag was provided using opts.finishFlush).
// If it's explicitly flushing at some other time, then we use
// Z_FULL_FLUSH. Otherwise, use Z_NO_FLUSH for maximum compression
// goodness.
if (last)
flushFlag = this._finishFlushFlag;
else {
flushFlag = this._flushFlag;
// once we've flushed the last of the queue, stop flushing and
// go back to the normal behavior.
if (chunk.length >= ws.length) {
this._flushFlag = this._opts.flush || constants.Z_NO_FLUSH;
}
}
this._processChunk(chunk, flushFlag, cb);
}
_processChunk(chunk, flushFlag, cb) {
var availInBefore = chunk && chunk.length;
var availOutBefore = this._chunkSize - this._offset;
var inOff = 0;
var self = this;
var async = typeof cb === 'function';
if (!async) {
var buffers = [];
var nread = 0;
var error;
this.on('error', function(er) {
error = er;
});
assert(this._handle, 'zlib binding closed');
do {
var res = this._handle.writeSync(flushFlag,
chunk, // in
inOff, // in_off
availInBefore, // in_len
this._buffer, // out
this._offset, //out_off
availOutBefore); // out_len
} while (!this._hadError && callback(res[0], res[1]));
if (this._hadError) {
throw error;
}
if (nread >= kMaxLength) {
_close(this);
throw new RangeError(kRangeErrorMessage);
}
var buf = Buffer.concat(buffers, nread);
_close(this);
return buf;
}
assert(this._handle, 'zlib binding closed');
var req = this._handle.write(flushFlag,
chunk, // in
inOff, // in_off
availInBefore, // in_len
this._buffer, // out
this._offset, //out_off
availOutBefore); // out_len
req.buffer = chunk;
req.callback = callback;
function callback(availInAfter, availOutAfter) {
// When the callback is used in an async write, the callback's
// context is the `req` object that was created. The req object
// is === this._handle, and that's why it's important to null
// out the values after they are done being used. `this._handle`
// can stay in memory longer than the callback and buffer are needed.
if (this) {
this.buffer = null;
this.callback = null;
}
if (self._hadError)
return;
var have = availOutBefore - availOutAfter;
assert(have >= 0, 'have should not go down');
if (have > 0) {
var out = self._buffer.slice(self._offset, self._offset + have);
self._offset += have;
// serve some output to the consumer.
if (async) {
self.push(out);
} else {
buffers.push(out);
nread += out.length;
}
}
// exhausted the output buffer, or used all the input create a new one.
if (availOutAfter === 0 || self._offset >= self._chunkSize) {
availOutBefore = self._chunkSize;
self._offset = 0;
self._buffer = Buffer.allocUnsafe(self._chunkSize);
}
if (availOutAfter === 0) {
// Not actually done. Need to reprocess.
// Also, update the availInBefore to the availInAfter value,
// so that if we have to hit it a third (fourth, etc.) time,
// it'll have the correct byte counts.
inOff += (availInBefore - availInAfter);
availInBefore = availInAfter;
if (!async)
return true;
var newReq = self._handle.write(flushFlag,
chunk,
inOff,
availInBefore,
self._buffer,
self._offset,
self._chunkSize);
newReq.callback = callback; // this same function
newReq.buffer = chunk;
return;
}
if (!async)
return false;
// finished with the chunk.
cb();
}
}
}
function _close(engine, callback) {
if (callback)
process.nextTick(callback);
// Caller may invoke .close after a zlib error (which will null _handle).
if (!engine._handle)
return;
engine._handle.close();
engine._handle = null;
}
function emitCloseNT(self) {
self.emit('close');
}
// generic zlib
// minimal 2-byte header
class Deflate extends Zlib {
constructor(opts) {
super(opts, constants.DEFLATE);
}
}
class Inflate extends Zlib {
constructor(opts) {
super(opts, constants.INFLATE);
}
}
class Gzip extends Zlib {
constructor(opts) {
super(opts, constants.GZIP);
}
}
class Gunzip extends Zlib {
constructor(opts) {
super(opts, constants.GUNZIP);
}
}
class DeflateRaw extends Zlib {
constructor(opts) {
super(opts, constants.DEFLATERAW);
}
}
class InflateRaw extends Zlib {
constructor(opts) {
super(opts, constants.INFLATERAW);
}
}
class Unzip extends Zlib {
constructor(opts) {
super(opts, constants.UNZIP);
}
}
function createConvenienceMethod(type, sync) {
if (sync) {
return function(buffer, opts) {
return zlibBufferSync(new type(opts), buffer);
};
} else {
return function(buffer, opts, callback) {
if (typeof opts === 'function') {
callback = opts;
opts = {};
}
return zlibBuffer(new type(opts), buffer, callback);
};
}
}
function createProperty(type) {
return {
configurable: true,
enumerable: true,
value: type
};
}
module.exports = {
Deflate: createClassWrapper(Deflate),
Inflate: createClassWrapper(Inflate),
Gzip: createClassWrapper(Gzip),
Gunzip: createClassWrapper(Gunzip),
DeflateRaw: createClassWrapper(DeflateRaw),
InflateRaw: createClassWrapper(InflateRaw),
Unzip: createClassWrapper(Unzip),
// Convenience methods.
// compress/decompress a string or buffer in one step.
deflate: createConvenienceMethod(Deflate, false),
deflateSync: createConvenienceMethod(Deflate, true),
gzip: createConvenienceMethod(Gzip, false),
gzipSync: createConvenienceMethod(Gzip, true),
deflateRaw: createConvenienceMethod(DeflateRaw, false),
deflateRawSync: createConvenienceMethod(DeflateRaw, true),
unzip: createConvenienceMethod(Unzip, false),
unzipSync: createConvenienceMethod(Unzip, true),
inflate: createConvenienceMethod(Inflate, false),
inflateSync: createConvenienceMethod(Inflate, true),
gunzip: createConvenienceMethod(Gunzip, false),
gunzipSync: createConvenienceMethod(Gunzip, true),
inflateRaw: createConvenienceMethod(InflateRaw, false),
inflateRawSync: createConvenienceMethod(InflateRaw, true)
};
Object.defineProperties(module.exports, {
createDeflate: createProperty(module.exports.Deflate),
createInflate: createProperty(module.exports.Inflate),
createDeflateRaw: createProperty(module.exports.DeflateRaw),
createInflateRaw: createProperty(module.exports.InflateRaw),
createGzip: createProperty(module.exports.Gzip),
createGunzip: createProperty(module.exports.Gunzip),
createUnzip: createProperty(module.exports.Unzip),
constants: {
configurable: false,
enumerable: true,
value: constants
},
codes: {
enumerable: true,
writable: false,
value: Object.freeze(codes)
}
});
// These should be considered deprecated
// expose all the zlib constants
const bkeys = Object.keys(constants);
for (var bk = 0; bk < bkeys.length; bk++) {
var bkey = bkeys[bk];
Object.defineProperty(module.exports, bkey, {
enumerable: true, value: constants[bkey], writable: false
});
}
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