c9-core/plugins/c9.nodeapi/stream.js

121 wiersze
2.7 KiB
JavaScript

define(function(require, exports, module) {
var events = require("events");
exports.Stream = Stream;
function Stream() {}
Stream.prototype = Object.create(events.EventEmitter.prototype, {
constructor: { value: Stream }
});
Stream.prototype.pipe = function(dest, options) {
var source = this;
function ondata(chunk) {
if (dest.writable) {
if (false === dest.write(chunk) && source.pause) {
source.pause();
}
}
}
source.on('data', ondata);
function ondrain() {
if (source.readable && source.resume) {
source.resume();
}
}
dest.on('drain', ondrain);
// If the 'end' option is not supplied, dest.end() will be called when
// source gets the 'end' or 'close' events. Only dest.end() once, and
// only when all sources have ended.
if (!dest._isStdio && (!options || options.end !== false)) {
dest._pipeCount = dest._pipeCount || 0;
dest._pipeCount++;
source.on('end', onend);
source.on('close', onclose);
}
var didOnEnd = false;
function onend() {
if (didOnEnd) return;
didOnEnd = true;
dest._pipeCount--;
// remove the listeners
cleanup();
if (dest._pipeCount > 0) {
// waiting for other incoming streams to end.
return;
}
dest.end();
}
function onclose() {
if (didOnEnd) return;
didOnEnd = true;
dest._pipeCount--;
// remove the listeners
cleanup();
if (dest._pipeCount > 0) {
// waiting for other incoming streams to end.
return;
}
dest.destroy();
}
// don't leave dangling pipes when there are errors.
function onerror(er) {
cleanup();
if (this.listeners('error').length === 0) {
throw er; // Unhandled stream error in pipe.
}
}
source.on('error', onerror);
dest.on('error', onerror);
// remove all the event listeners that were added.
function cleanup() {
source.removeListener('data', ondata);
dest.removeListener('drain', ondrain);
source.removeListener('end', onend);
source.removeListener('close', onclose);
source.removeListener('error', onerror);
dest.removeListener('error', onerror);
source.removeListener('end', cleanup);
source.removeListener('close', cleanup);
dest.removeListener('end', cleanup);
dest.removeListener('close', cleanup);
}
source.on('end', cleanup);
source.on('close', cleanup);
dest.on('end', cleanup);
dest.on('close', cleanup);
dest.emit('pipe', source);
// Allow for unix-like usage: A.pipe(B).pipe(C)
return dest;
};
});