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-rw-r--r--toolkit/jetpack/sdk/io/byte-streams.js104
1 files changed, 104 insertions, 0 deletions
diff --git a/toolkit/jetpack/sdk/io/byte-streams.js b/toolkit/jetpack/sdk/io/byte-streams.js
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index 000000000..6afab4369
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+++ b/toolkit/jetpack/sdk/io/byte-streams.js
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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;
+ }
+};