The Tor Browser: comparison addon-sdk/source/lib/sdk/io/text-streams.js

comparison: addon-sdk/source/lib/sdk/io/text-streams.js

addon-sdk/source/lib/sdk/io/text-streams.js

changeset 0: 6474c204b198

equal deleted inserted replaced

--1:000000000000
+:f06a842e7472
+/* 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"
+};
+const {Cc,Ci,Cu,components} = require("chrome");
+var NetUtil = {};
+Cu.import("resource://gre/modules/NetUtil.jsm", NetUtil);
+NetUtil = NetUtil.NetUtil;
+// NetUtil.asyncCopy() uses this buffer length, and since we call it, for best
+// performance we use it, too.
+const BUFFER_BYTE_LEN = 0x8000;
+const PR_UINT32_MAX = 0xffffffff;
+const DEFAULT_CHARSET = "UTF-8";
+exports.TextReader = TextReader;
+exports.TextWriter = TextWriter;
+/**
+* An input stream that reads text from a backing stream using a given text
+* encoding.
+*
+* @param inputStream
+*        The stream is backed by this nsIInputStream.  It must already be
+*        opened.
+* @param charset
+*        Text in inputStream is expected to be in this character encoding.  If
+*        not given, "UTF-8" is assumed.  See nsICharsetConverterManager.idl for
+*        documentation on how to determine other valid values for this.
+*/
+function TextReader(inputStream, charset) {
+const self = this;
+charset = checkCharset(charset);
+let stream = Cc["@mozilla.org/intl/converter-input-stream;1"].
+createInstance(Ci.nsIConverterInputStream);
+stream.init(inputStream, charset, BUFFER_BYTE_LEN,
+Ci.nsIConverterInputStream.DEFAULT_REPLACEMENT_CHARACTER);
+let manager = new StreamManager(this, stream);
+/**
+* Reads a string from the stream.  If the stream is closed, an exception is
+* thrown.
+*
+* @param  numChars
+*         The number of characters to read.  If not given, the remainder of
+*         the stream is read.
+* @return The string read.  If the stream is already at EOS, returns the
+*         empty string.
+*/
+this.read = function TextReader_read(numChars) {
+manager.ensureOpened();
+let readAll = false;
+if (typeof(numChars) === "number")
+numChars = Math.max(numChars, 0);
+else
+readAll = true;
+let str = "";
+let totalRead = 0;
+let chunkRead = 1;
+// Read in numChars or until EOS, whichever comes first.  Note that the
+// units here are characters, not bytes.
+while (true) {
+let chunk = {};
+let toRead = readAll ?
+PR_UINT32_MAX :
+Math.min(numChars - totalRead, PR_UINT32_MAX);
+if (toRead <= 0 || chunkRead <= 0)
+break;
+// The converter stream reads in at most BUFFER_BYTE_LEN bytes in a call
+// to readString, enough to fill its byte buffer.  chunkRead will be the
+// number of characters encoded by the bytes in that buffer.
+chunkRead = stream.readString(toRead, chunk);
+str += chunk.value;
+totalRead += chunkRead;
+}
+return str;
+};
+}
+/**
+* A buffered output stream that writes text to a backing stream using a given
+* text encoding.
+*
+* @param outputStream
+*        The stream is backed by this nsIOutputStream.  It must already be
+*        opened.
+* @param charset
+*        Text will be written to outputStream using this character encoding.
+*        If not given, "UTF-8" is assumed.  See nsICharsetConverterManager.idl
+*        for documentation on how to determine other valid values for this.
+*/
+function TextWriter(outputStream, charset) {
+const self = this;
+charset = checkCharset(charset);
+let stream = outputStream;
+// Buffer outputStream if it's not already.
+let ioUtils = Cc["@mozilla.org/io-util;1"].getService(Ci.nsIIOUtil);
+if (!ioUtils.outputStreamIsBuffered(outputStream)) {
+stream = Cc["@mozilla.org/network/buffered-output-stream;1"].
+createInstance(Ci.nsIBufferedOutputStream);
+stream.init(outputStream, BUFFER_BYTE_LEN);
+}
+// I'd like to use nsIConverterOutputStream.  But NetUtil.asyncCopy(), which
+// we use below in writeAsync(), naturally expects its sink to be an instance
+// of nsIOutputStream, which nsIConverterOutputStream's only implementation is
+// not.  So we use uconv and manually convert all strings before writing to
+// outputStream.
+let uconv = Cc["@mozilla.org/intl/scriptableunicodeconverter"].
+createInstance(Ci.nsIScriptableUnicodeConverter);
+uconv.charset = charset;
+let manager = new StreamManager(this, stream);
+/**
+* Flushes the backing stream's buffer.
+*/
+this.flush = function TextWriter_flush() {
+manager.ensureOpened();
+stream.flush();
+};
+/**
+* Writes a string to the stream.  If the stream is closed, an exception is
+* thrown.
+*
+* @param str
+*        The string to write.
+*/
+this.write = function TextWriter_write(str) {
+manager.ensureOpened();
+let istream = uconv.convertToInputStream(str);
+let len = istream.available();
+while (len > 0) {
+stream.writeFrom(istream, len);
+len = istream.available();
+}
+istream.close();
+};
+/**
+* Writes a string on a background thread.  After the write completes, the
+* backing stream's buffer is flushed, and both the stream and the backing
+* stream are closed, also on the background thread.  If the stream is already
+* closed, an exception is thrown immediately.
+*
+* @param str
+*        The string to write.
+* @param callback
+*        An optional function.  If given, it's called as callback(error) when
+*        the write completes.  error is an Error object or undefined if there
+*        was no error.  Inside callback, |this| is the stream object.
+*/
+this.writeAsync = function TextWriter_writeAsync(str, callback) {
+manager.ensureOpened();
+let istream = uconv.convertToInputStream(str);
+NetUtil.asyncCopy(istream, stream, function (result) {
+let err = components.isSuccessCode(result) ? undefined :
+new Error("An error occured while writing to the stream: " + result);
+if (err)
+console.error(err);
+// asyncCopy() closes its output (and input) stream.
+manager.opened = false;
+if (typeof(callback) === "function") {
+try {
+callback.call(self, err);
+}
+catch (exc) {
+console.exception(exc);
+}
+}
+});
+};
+}
+// This manages the lifetime of stream, a TextReader or TextWriter.  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;
+/**
+* True iff the stream is closed.
+*/
+stream.__defineGetter__("closed", function stream_closed() {
+return !self.opened;
+});
+/**
+* Closes both the stream and its backing stream.  If the stream is already
+* closed, an exception is thrown.  For TextWriters, this first flushes the
+* backing stream's buffer.
+*/
+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() {
+// TextWriter.writeAsync() causes rawStream to close and therefore sets
+// opened to false, so check that we're still opened.
+if (this.opened) {
+// Calling close() on both an nsIUnicharInputStream and
+// nsIBufferedOutputStream closes their backing streams.  It also forces
+// nsIOutputStreams to flush first.
+this.rawStream.close();
+this.opened = false;
+}
+}
+};
+function checkCharset(charset) {
+return typeof(charset) === "string" ? charset : DEFAULT_CHARSET;
+}