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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
"use strict";
module.metadata = {
"stability": "experimental"
};
exports.ByteReader = ByteReader;
exports.ByteWriter = ByteWriter;
const {Cc, Ci} = require("chrome");
// This just controls the maximum number of bytes we read in at one time.
const BUFFER_BYTE_LEN = 0x8000;
function ByteReader(inputStream) {
const self = this;
let stream = Cc["@mozilla.org/binaryinputstream;1"].
createInstance(Ci.nsIBinaryInputStream);
stream.setInputStream(inputStream);
let manager = new StreamManager(this, stream);
this.read = function ByteReader_read(numBytes) {
manager.ensureOpened();
if (typeof(numBytes) !== "number")
numBytes = Infinity;
let data = "";
let read = 0;
try {
while (true) {
let avail = stream.available();
let toRead = Math.min(numBytes - read, avail, BUFFER_BYTE_LEN);
if (toRead <= 0)
break;
data += stream.readBytes(toRead);
read += toRead;
}
}
catch (err) {
throw new Error("Error reading from stream: " + err);
}
return data;
};
}
function ByteWriter(outputStream) {
const self = this;
let stream = Cc["@mozilla.org/binaryoutputstream;1"].
createInstance(Ci.nsIBinaryOutputStream);
stream.setOutputStream(outputStream);
let manager = new StreamManager(this, stream);
this.write = function ByteWriter_write(str) {
manager.ensureOpened();
try {
stream.writeBytes(str, str.length);
}
catch (err) {
throw new Error("Error writing to stream: " + err);
}
};
}
// This manages the lifetime of stream, a ByteReader or ByteWriter. It defines
// closed and close() on stream and registers an unload listener that closes
// rawStream if it's still opened. It also provides ensureOpened(), which
// throws an exception if the stream is closed.
function StreamManager(stream, rawStream) {
const self = this;
this.rawStream = rawStream;
this.opened = true;
stream.__defineGetter__("closed", function stream_closed() {
return !self.opened;
});
stream.close = function stream_close() {
self.ensureOpened();
self.unload();
};
require("../system/unload").ensure(this);
}
StreamManager.prototype = {
ensureOpened: function StreamManager_ensureOpened() {
if (!this.opened)
throw new Error("The stream is closed and cannot be used.");
},
unload: function StreamManager_unload() {
this.rawStream.close();
this.opened = false;
}
};
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