--- /dev/null
+// A bit simpler than readable streams.
+// Implement an async ._write(chunk, encoding, cb), and it'll handle all
+// the drain event emission and buffering.
+
+'use strict';
+
+module.exports = Writable;
+
+/*<replacement>*/
+var processNextTick = require('process-nextick-args');
+/*</replacement>*/
+
+/*<replacement>*/
+var asyncWrite = !process.browser && ['v0.10', 'v0.9.'].indexOf(process.version.slice(0, 5)) > -1 ? setImmediate : processNextTick;
+/*</replacement>*/
+
+/*<replacement>*/
+var Buffer = require('buffer').Buffer;
+/*</replacement>*/
+
+Writable.WritableState = WritableState;
+
+/*<replacement>*/
+var util = require('core-util-is');
+util.inherits = require('inherits');
+/*</replacement>*/
+
+/*<replacement>*/
+var internalUtil = {
+ deprecate: require('util-deprecate')
+};
+/*</replacement>*/
+
+/*<replacement>*/
+var Stream;
+(function () {
+ try {
+ Stream = require('st' + 'ream');
+ } catch (_) {} finally {
+ if (!Stream) Stream = require('events').EventEmitter;
+ }
+})();
+/*</replacement>*/
+
+var Buffer = require('buffer').Buffer;
+
+util.inherits(Writable, Stream);
+
+function nop() {}
+
+function WriteReq(chunk, encoding, cb) {
+ this.chunk = chunk;
+ this.encoding = encoding;
+ this.callback = cb;
+ this.next = null;
+}
+
+var Duplex;
+function WritableState(options, stream) {
+ Duplex = Duplex || require('./_stream_duplex');
+
+ options = options || {};
+
+ // object stream flag to indicate whether or not this stream
+ // contains buffers or objects.
+ this.objectMode = !!options.objectMode;
+
+ if (stream instanceof Duplex) this.objectMode = this.objectMode || !!options.writableObjectMode;
+
+ // the point at which write() starts returning false
+ // Note: 0 is a valid value, means that we always return false if
+ // the entire buffer is not flushed immediately on write()
+ var hwm = options.highWaterMark;
+ var defaultHwm = this.objectMode ? 16 : 16 * 1024;
+ this.highWaterMark = hwm || hwm === 0 ? hwm : defaultHwm;
+
+ // cast to ints.
+ this.highWaterMark = ~ ~this.highWaterMark;
+
+ this.needDrain = false;
+ // at the start of calling end()
+ this.ending = false;
+ // when end() has been called, and returned
+ this.ended = false;
+ // when 'finish' is emitted
+ this.finished = false;
+
+ // should we decode strings into buffers before passing to _write?
+ // this is here so that some node-core streams can optimize string
+ // handling at a lower level.
+ var noDecode = options.decodeStrings === false;
+ this.decodeStrings = !noDecode;
+
+ // Crypto is kind of old and crusty. Historically, its default string
+ // encoding is 'binary' so we have to make this configurable.
+ // Everything else in the universe uses 'utf8', though.
+ this.defaultEncoding = options.defaultEncoding || 'utf8';
+
+ // not an actual buffer we keep track of, but a measurement
+ // of how much we're waiting to get pushed to some underlying
+ // socket or file.
+ this.length = 0;
+
+ // a flag to see when we're in the middle of a write.
+ this.writing = false;
+
+ // when true all writes will be buffered until .uncork() call
+ this.corked = 0;
+
+ // a flag to be able to tell if the onwrite cb is called immediately,
+ // or on a later tick. We set this to true at first, because any
+ // actions that shouldn't happen until "later" should generally also
+ // not happen before the first write call.
+ this.sync = true;
+
+ // a flag to know if we're processing previously buffered items, which
+ // may call the _write() callback in the same tick, so that we don't
+ // end up in an overlapped onwrite situation.
+ this.bufferProcessing = false;
+
+ // the callback that's passed to _write(chunk,cb)
+ this.onwrite = function (er) {
+ onwrite(stream, er);
+ };
+
+ // the callback that the user supplies to write(chunk,encoding,cb)
+ this.writecb = null;
+
+ // the amount that is being written when _write is called.
+ this.writelen = 0;
+
+ this.bufferedRequest = null;
+ this.lastBufferedRequest = null;
+
+ // number of pending user-supplied write callbacks
+ // this must be 0 before 'finish' can be emitted
+ this.pendingcb = 0;
+
+ // emit prefinish if the only thing we're waiting for is _write cbs
+ // This is relevant for synchronous Transform streams
+ this.prefinished = false;
+
+ // True if the error was already emitted and should not be thrown again
+ this.errorEmitted = false;
+
+ // count buffered requests
+ this.bufferedRequestCount = 0;
+
+ // create the two objects needed to store the corked requests
+ // they are not a linked list, as no new elements are inserted in there
+ this.corkedRequestsFree = new CorkedRequest(this);
+ this.corkedRequestsFree.next = new CorkedRequest(this);
+}
+
+WritableState.prototype.getBuffer = function writableStateGetBuffer() {
+ var current = this.bufferedRequest;
+ var out = [];
+ while (current) {
+ out.push(current);
+ current = current.next;
+ }
+ return out;
+};
+
+(function () {
+ try {
+ Object.defineProperty(WritableState.prototype, 'buffer', {
+ get: internalUtil.deprecate(function () {
+ return this.getBuffer();
+ }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.')
+ });
+ } catch (_) {}
+})();
+
+var Duplex;
+function Writable(options) {
+ Duplex = Duplex || require('./_stream_duplex');
+
+ // Writable ctor is applied to Duplexes, though they're not
+ // instanceof Writable, they're instanceof Readable.
+ if (!(this instanceof Writable) && !(this instanceof Duplex)) return new Writable(options);
+
+ this._writableState = new WritableState(options, this);
+
+ // legacy.
+ this.writable = true;
+
+ if (options) {
+ if (typeof options.write === 'function') this._write = options.write;
+
+ if (typeof options.writev === 'function') this._writev = options.writev;
+ }
+
+ Stream.call(this);
+}
+
+// Otherwise people can pipe Writable streams, which is just wrong.
+Writable.prototype.pipe = function () {
+ this.emit('error', new Error('Cannot pipe. Not readable.'));
+};
+
+function writeAfterEnd(stream, cb) {
+ var er = new Error('write after end');
+ // TODO: defer error events consistently everywhere, not just the cb
+ stream.emit('error', er);
+ processNextTick(cb, er);
+}
+
+// If we get something that is not a buffer, string, null, or undefined,
+// and we're not in objectMode, then that's an error.
+// Otherwise stream chunks are all considered to be of length=1, and the
+// watermarks determine how many objects to keep in the buffer, rather than
+// how many bytes or characters.
+function validChunk(stream, state, chunk, cb) {
+ var valid = true;
+
+ if (!Buffer.isBuffer(chunk) && typeof chunk !== 'string' && chunk !== null && chunk !== undefined && !state.objectMode) {
+ var er = new TypeError('Invalid non-string/buffer chunk');
+ stream.emit('error', er);
+ processNextTick(cb, er);
+ valid = false;
+ }
+ return valid;
+}
+
+Writable.prototype.write = function (chunk, encoding, cb) {
+ var state = this._writableState;
+ var ret = false;
+
+ if (typeof encoding === 'function') {
+ cb = encoding;
+ encoding = null;
+ }
+
+ if (Buffer.isBuffer(chunk)) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;
+
+ if (typeof cb !== 'function') cb = nop;
+
+ if (state.ended) writeAfterEnd(this, cb);else if (validChunk(this, state, chunk, cb)) {
+ state.pendingcb++;
+ ret = writeOrBuffer(this, state, chunk, encoding, cb);
+ }
+
+ return ret;
+};
+
+Writable.prototype.cork = function () {
+ var state = this._writableState;
+
+ state.corked++;
+};
+
+Writable.prototype.uncork = function () {
+ var state = this._writableState;
+
+ if (state.corked) {
+ state.corked--;
+
+ if (!state.writing && !state.corked && !state.finished && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
+ }
+};
+
+Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
+ // node::ParseEncoding() requires lower case.
+ if (typeof encoding === 'string') encoding = encoding.toLowerCase();
+ if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new TypeError('Unknown encoding: ' + encoding);
+ this._writableState.defaultEncoding = encoding;
+};
+
+function decodeChunk(state, chunk, encoding) {
+ if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
+ chunk = new Buffer(chunk, encoding);
+ }
+ return chunk;
+}
+
+// if we're already writing something, then just put this
+// in the queue, and wait our turn. Otherwise, call _write
+// If we return false, then we need a drain event, so set that flag.
+function writeOrBuffer(stream, state, chunk, encoding, cb) {
+ chunk = decodeChunk(state, chunk, encoding);
+
+ if (Buffer.isBuffer(chunk)) encoding = 'buffer';
+ var len = state.objectMode ? 1 : chunk.length;
+
+ state.length += len;
+
+ var ret = state.length < state.highWaterMark;
+ // we must ensure that previous needDrain will not be reset to false.
+ if (!ret) state.needDrain = true;
+
+ if (state.writing || state.corked) {
+ var last = state.lastBufferedRequest;
+ state.lastBufferedRequest = new WriteReq(chunk, encoding, cb);
+ if (last) {
+ last.next = state.lastBufferedRequest;
+ } else {
+ state.bufferedRequest = state.lastBufferedRequest;
+ }
+ state.bufferedRequestCount += 1;
+ } else {
+ doWrite(stream, state, false, len, chunk, encoding, cb);
+ }
+
+ return ret;
+}
+
+function doWrite(stream, state, writev, len, chunk, encoding, cb) {
+ state.writelen = len;
+ state.writecb = cb;
+ state.writing = true;
+ state.sync = true;
+ if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
+ state.sync = false;
+}
+
+function onwriteError(stream, state, sync, er, cb) {
+ --state.pendingcb;
+ if (sync) processNextTick(cb, er);else cb(er);
+
+ stream._writableState.errorEmitted = true;
+ stream.emit('error', er);
+}
+
+function onwriteStateUpdate(state) {
+ state.writing = false;
+ state.writecb = null;
+ state.length -= state.writelen;
+ state.writelen = 0;
+}
+
+function onwrite(stream, er) {
+ var state = stream._writableState;
+ var sync = state.sync;
+ var cb = state.writecb;
+
+ onwriteStateUpdate(state);
+
+ if (er) onwriteError(stream, state, sync, er, cb);else {
+ // Check if we're actually ready to finish, but don't emit yet
+ var finished = needFinish(state);
+
+ if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
+ clearBuffer(stream, state);
+ }
+
+ if (sync) {
+ /*<replacement>*/
+ asyncWrite(afterWrite, stream, state, finished, cb);
+ /*</replacement>*/
+ } else {
+ afterWrite(stream, state, finished, cb);
+ }
+ }
+}
+
+function afterWrite(stream, state, finished, cb) {
+ if (!finished) onwriteDrain(stream, state);
+ state.pendingcb--;
+ cb();
+ finishMaybe(stream, state);
+}
+
+// Must force callback to be called on nextTick, so that we don't
+// emit 'drain' before the write() consumer gets the 'false' return
+// value, and has a chance to attach a 'drain' listener.
+function onwriteDrain(stream, state) {
+ if (state.length === 0 && state.needDrain) {
+ state.needDrain = false;
+ stream.emit('drain');
+ }
+}
+
+// if there's something in the buffer waiting, then process it
+function clearBuffer(stream, state) {
+ state.bufferProcessing = true;
+ var entry = state.bufferedRequest;
+
+ if (stream._writev && entry && entry.next) {
+ // Fast case, write everything using _writev()
+ var l = state.bufferedRequestCount;
+ var buffer = new Array(l);
+ var holder = state.corkedRequestsFree;
+ holder.entry = entry;
+
+ var count = 0;
+ while (entry) {
+ buffer[count] = entry;
+ entry = entry.next;
+ count += 1;
+ }
+
+ doWrite(stream, state, true, state.length, buffer, '', holder.finish);
+
+ // doWrite is always async, defer these to save a bit of time
+ // as the hot path ends with doWrite
+ state.pendingcb++;
+ state.lastBufferedRequest = null;
+ state.corkedRequestsFree = holder.next;
+ holder.next = null;
+ } else {
+ // Slow case, write chunks one-by-one
+ while (entry) {
+ var chunk = entry.chunk;
+ var encoding = entry.encoding;
+ var cb = entry.callback;
+ var len = state.objectMode ? 1 : chunk.length;
+
+ doWrite(stream, state, false, len, chunk, encoding, cb);
+ entry = entry.next;
+ // if we didn't call the onwrite immediately, then
+ // it means that we need to wait until it does.
+ // also, that means that the chunk and cb are currently
+ // being processed, so move the buffer counter past them.
+ if (state.writing) {
+ break;
+ }
+ }
+
+ if (entry === null) state.lastBufferedRequest = null;
+ }
+
+ state.bufferedRequestCount = 0;
+ state.bufferedRequest = entry;
+ state.bufferProcessing = false;
+}
+
+Writable.prototype._write = function (chunk, encoding, cb) {
+ cb(new Error('not implemented'));
+};
+
+Writable.prototype._writev = null;
+
+Writable.prototype.end = function (chunk, encoding, cb) {
+ var state = this._writableState;
+
+ if (typeof chunk === 'function') {
+ cb = chunk;
+ chunk = null;
+ encoding = null;
+ } else if (typeof encoding === 'function') {
+ cb = encoding;
+ encoding = null;
+ }
+
+ if (chunk !== null && chunk !== undefined) this.write(chunk, encoding);
+
+ // .end() fully uncorks
+ if (state.corked) {
+ state.corked = 1;
+ this.uncork();
+ }
+
+ // ignore unnecessary end() calls.
+ if (!state.ending && !state.finished) endWritable(this, state, cb);
+};
+
+function needFinish(state) {
+ return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
+}
+
+function prefinish(stream, state) {
+ if (!state.prefinished) {
+ state.prefinished = true;
+ stream.emit('prefinish');
+ }
+}
+
+function finishMaybe(stream, state) {
+ var need = needFinish(state);
+ if (need) {
+ if (state.pendingcb === 0) {
+ prefinish(stream, state);
+ state.finished = true;
+ stream.emit('finish');
+ } else {
+ prefinish(stream, state);
+ }
+ }
+ return need;
+}
+
+function endWritable(stream, state, cb) {
+ state.ending = true;
+ finishMaybe(stream, state);
+ if (cb) {
+ if (state.finished) processNextTick(cb);else stream.once('finish', cb);
+ }
+ state.ended = true;
+ stream.writable = false;
+}
+
+// It seems a linked list but it is not
+// there will be only 2 of these for each stream
+function CorkedRequest(state) {
+ var _this = this;
+
+ this.next = null;
+ this.entry = null;
+
+ this.finish = function (err) {
+ var entry = _this.entry;
+ _this.entry = null;
+ while (entry) {
+ var cb = entry.callback;
+ state.pendingcb--;
+ cb(err);
+ entry = entry.next;
+ }
+ if (state.corkedRequestsFree) {
+ state.corkedRequestsFree.next = _this;
+ } else {
+ state.corkedRequestsFree = _this;
+ }
+ };
+}
\ No newline at end of file
projects / yaffs-website / blobdiff