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