diff options
Diffstat (limited to 'tools/addon-sdk-1.7/packages/api-utils/lib/byte-streams.js')
-rw-r--r-- | tools/addon-sdk-1.7/packages/api-utils/lib/byte-streams.js | 102 |
1 files changed, 102 insertions, 0 deletions
diff --git a/tools/addon-sdk-1.7/packages/api-utils/lib/byte-streams.js b/tools/addon-sdk-1.7/packages/api-utils/lib/byte-streams.js new file mode 100644 index 0000000..edc8407 --- /dev/null +++ b/tools/addon-sdk-1.7/packages/api-utils/lib/byte-streams.js @@ -0,0 +1,102 @@ +/* -*- Mode: Java; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim:set ts=2 sw=2 sts=2 et filetype=javascript + * 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"; + +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("./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; + } +}; |