+++ /dev/null
-// Copyright Joyent, Inc. and other Node contributors.
-//
-// Permission is hereby granted, free of charge, to any person obtaining a
-// copy of this software and associated documentation files (the
-// "Software"), to deal in the Software without restriction, including
-// without limitation the rights to use, copy, modify, merge, publish,
-// distribute, sublicense, and/or sell copies of the Software, and to permit
-// persons to whom the Software is furnished to do so, subject to the
-// following conditions:
-//
-// The above copyright notice and this permission notice shall be included
-// in all copies or substantial portions of the Software.
-//
-// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
-// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
-// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
-// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
-// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
-// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
-// USE OR OTHER DEALINGS IN THE SOFTWARE.
-// a transform stream is a readable/writable stream where you do
-// something with the data. Sometimes it's called a "filter",
-// but that's not a great name for it, since that implies a thing where
-// some bits pass through, and others are simply ignored. (That would
-// be a valid example of a transform, of course.)
-//
-// While the output is causally related to the input, it's not a
-// necessarily symmetric or synchronous transformation. For example,
-// a zlib stream might take multiple plain-text writes(), and then
-// emit a single compressed chunk some time in the future.
-//
-// Here's how this works:
-//
-// The Transform stream has all the aspects of the readable and writable
-// stream classes. When you write(chunk), that calls _write(chunk,cb)
-// internally, and returns false if there's a lot of pending writes
-// buffered up. When you call read(), that calls _read(n) until
-// there's enough pending readable data buffered up.
-//
-// In a transform stream, the written data is placed in a buffer. When
-// _read(n) is called, it transforms the queued up data, calling the
-// buffered _write cb's as it consumes chunks. If consuming a single
-// written chunk would result in multiple output chunks, then the first
-// outputted bit calls the readcb, and subsequent chunks just go into
-// the read buffer, and will cause it to emit 'readable' if necessary.
-//
-// This way, back-pressure is actually determined by the reading side,
-// since _read has to be called to start processing a new chunk. However,
-// a pathological inflate type of transform can cause excessive buffering
-// here. For example, imagine a stream where every byte of input is
-// interpreted as an integer from 0-255, and then results in that many
-// bytes of output. Writing the 4 bytes {ff,ff,ff,ff} would result in
-// 1kb of data being output. In this case, you could write a very small
-// amount of input, and end up with a very large amount of output. In
-// such a pathological inflating mechanism, there'd be no way to tell
-// the system to stop doing the transform. A single 4MB write could
-// cause the system to run out of memory.
-//
-// However, even in such a pathological case, only a single written chunk
-// would be consumed, and then the rest would wait (un-transformed) until
-// the results of the previous transformed chunk were consumed.
-'use strict';
-
-module.exports = Transform;
-
-var _require$codes = require('../errors').codes,
- ERR_METHOD_NOT_IMPLEMENTED = _require$codes.ERR_METHOD_NOT_IMPLEMENTED,
- ERR_MULTIPLE_CALLBACK = _require$codes.ERR_MULTIPLE_CALLBACK,
- ERR_TRANSFORM_ALREADY_TRANSFORMING = _require$codes.ERR_TRANSFORM_ALREADY_TRANSFORMING,
- ERR_TRANSFORM_WITH_LENGTH_0 = _require$codes.ERR_TRANSFORM_WITH_LENGTH_0;
-
-var Duplex = require('./_stream_duplex');
-
-require('inherits')(Transform, Duplex);
-
-function afterTransform(er, data) {
- var ts = this._transformState;
- ts.transforming = false;
- var cb = ts.writecb;
-
- if (cb === null) {
- return this.emit('error', new ERR_MULTIPLE_CALLBACK());
- }
-
- ts.writechunk = null;
- ts.writecb = null;
- if (data != null) // single equals check for both `null` and `undefined`
- this.push(data);
- cb(er);
- var rs = this._readableState;
- rs.reading = false;
-
- if (rs.needReadable || rs.length < rs.highWaterMark) {
- this._read(rs.highWaterMark);
- }
-}
-
-function Transform(options) {
- if (!(this instanceof Transform)) return new Transform(options);
- Duplex.call(this, options);
- this._transformState = {
- afterTransform: afterTransform.bind(this),
- needTransform: false,
- transforming: false,
- writecb: null,
- writechunk: null,
- writeencoding: null
- }; // start out asking for a readable event once data is transformed.
-
- this._readableState.needReadable = true; // we have implemented the _read method, and done the other things
- // that Readable wants before the first _read call, so unset the
- // sync guard flag.
-
- this._readableState.sync = false;
-
- if (options) {
- if (typeof options.transform === 'function') this._transform = options.transform;
- if (typeof options.flush === 'function') this._flush = options.flush;
- } // When the writable side finishes, then flush out anything remaining.
-
-
- this.on('prefinish', prefinish);
-}
-
-function prefinish() {
- var _this = this;
-
- if (typeof this._flush === 'function' && !this._readableState.destroyed) {
- this._flush(function (er, data) {
- done(_this, er, data);
- });
- } else {
- done(this, null, null);
- }
-}
-
-Transform.prototype.push = function (chunk, encoding) {
- this._transformState.needTransform = false;
- return Duplex.prototype.push.call(this, chunk, encoding);
-}; // This is the part where you do stuff!
-// override this function in implementation classes.
-// 'chunk' is an input chunk.
-//
-// Call `push(newChunk)` to pass along transformed output
-// to the readable side. You may call 'push' zero or more times.
-//
-// Call `cb(err)` when you are done with this chunk. If you pass
-// an error, then that'll put the hurt on the whole operation. If you
-// never call cb(), then you'll never get another chunk.
-
-
-Transform.prototype._transform = function (chunk, encoding, cb) {
- cb(new ERR_METHOD_NOT_IMPLEMENTED('_transform()'));
-};
-
-Transform.prototype._write = function (chunk, encoding, cb) {
- var ts = this._transformState;
- ts.writecb = cb;
- ts.writechunk = chunk;
- ts.writeencoding = encoding;
-
- if (!ts.transforming) {
- var rs = this._readableState;
- if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
- }
-}; // Doesn't matter what the args are here.
-// _transform does all the work.
-// That we got here means that the readable side wants more data.
-
-
-Transform.prototype._read = function (n) {
- var ts = this._transformState;
-
- if (ts.writechunk !== null && !ts.transforming) {
- ts.transforming = true;
-
- this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
- } else {
- // mark that we need a transform, so that any data that comes in
- // will get processed, now that we've asked for it.
- ts.needTransform = true;
- }
-};
-
-Transform.prototype._destroy = function (err, cb) {
- Duplex.prototype._destroy.call(this, err, function (err2) {
- cb(err2);
- });
-};
-
-function done(stream, er, data) {
- if (er) return stream.emit('error', er);
- if (data != null) // single equals check for both `null` and `undefined`
- stream.push(data); // TODO(BridgeAR): Write a test for these two error cases
- // if there's nothing in the write buffer, then that means
- // that nothing more will ever be provided
-
- if (stream._writableState.length) throw new ERR_TRANSFORM_WITH_LENGTH_0();
- if (stream._transformState.transforming) throw new ERR_TRANSFORM_ALREADY_TRANSFORMING();
- return stream.push(null);
-}
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projects / dotfiles / .git / blobdiff