98 lines
2.6 KiB
JavaScript
98 lines
2.6 KiB
JavaScript
var util = require("util"),
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stream = require("stream"),
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constants = require("./constants");
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// TODO: clear up specs on returning false from a write and emitting a drain event.
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// Does this mean if I return false from a write, I should ignore any write requests between that false return and the drain event?
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var WritableStreamBuffer = module.exports = function(opts) {
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var that = this;
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stream.Stream.call(this);
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opts = opts || {};
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var initialSize = opts.initialSize || constants.DEFAULT_INITIAL_SIZE;
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var incrementAmount = opts.incrementAmount || constants.DEFAULT_INCREMENT_AMOUNT;
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var buffer = new Buffer(initialSize);
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var size = 0;
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this.writable = true;
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this.readable = false;
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this.size = function() {
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return size;
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};
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this.maxSize = function() {
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return buffer.length;
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};
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this.getContents = function(length) {
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if(!size) return false;
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var data = new Buffer(Math.min(length || size, size));
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buffer.copy(data, 0, 0, data.length);
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if(data.length < size)
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buffer.copy(buffer, 0, data.length);
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size -= data.length;
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return data;
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};
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this.getContentsAsString = function(encoding, length) {
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if(!size) return false;
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var data = buffer.toString(encoding || "utf8", 0, Math.min(length || size, size));
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var dataLength = Buffer.byteLength(data);
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if(dataLength < size)
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buffer.copy(buffer, 0, dataLength);
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size -= dataLength;
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return data;
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};
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var increaseBufferIfNecessary = function(incomingDataSize) {
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if((buffer.length - size) < incomingDataSize) {
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var factor = Math.ceil((incomingDataSize - (buffer.length - size)) / incrementAmount);
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var newBuffer = new Buffer(buffer.length + (incrementAmount * factor));
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buffer.copy(newBuffer, 0, 0, size);
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buffer = newBuffer;
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}
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};
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this.write = function(data, encoding, callback) {
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if(!that.writable) return;
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if(Buffer.isBuffer(data)) {
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increaseBufferIfNecessary(data.length);
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data.copy(buffer, size, 0);
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size += data.length;
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}
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else {
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data = data + "";
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increaseBufferIfNecessary(Buffer.byteLength(data));
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buffer.write(data, size, encoding || "utf8");
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size += Buffer.byteLength(data);
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}
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if(typeof callback === "function") { callback() ;}
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};
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this.end = function() {
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var args = Array.prototype.slice.apply(arguments);
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if(args.length) that.write.apply(that, args);
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that.emit('finish');
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that.destroy();
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};
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this.destroySoon = this.destroy = function() {
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that.writable = false;
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that.emit("close");
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};
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};
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util.inherits(WritableStreamBuffer, stream.Stream);
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