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

comparison: addon-sdk/source/lib/sdk/io/buffer.js

addon-sdk/source/lib/sdk/io/buffer.js

branch: TOR_BUG_9701
changeset 15: b8a032363ba2

equal deleted inserted replaced

--1:000000000000
+:5db294e8518e
+/* 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'
+};
+/*
+* Encodings supported by TextEncoder/Decoder:
+* utf-8, utf-16le, utf-16be
+* http://encoding.spec.whatwg.org/#interface-textencoder
+*
+* Node however supports the following encodings:
+* ascii, utf-8, utf-16le, usc2, base64, hex
+*/
+const { Cu } = require('chrome');
+const { isNumber } = require('sdk/lang/type');
+const { TextEncoder, TextDecoder } = Cu.import('resource://gre/modules/commonjs/toolkit/loader.js', {});
+exports.TextEncoder = TextEncoder;
+exports.TextDecoder = TextDecoder;
+/**
+* Use WeakMaps to work around Bug 929146, which prevents us from adding
+* getters or values to typed arrays
+* https://bugzilla.mozilla.org/show_bug.cgi?id=929146
+*/
+const parents = new WeakMap();
+const views = new WeakMap();
+function Buffer(subject, encoding /*, bufferLength */) {
+// Allow invocation without `new` constructor
+if (!(this instanceof Buffer))
+return new Buffer(subject, encoding, arguments[2]);
+var type = typeof(subject);
+switch (type) {
+case 'number':
+// Create typed array of the given size if number.
+try {
+let buffer = new Uint8Array(subject > 0 ? Math.floor(subject) : 0);
+return buffer;
+} catch (e) {
+if (/size and count too large/.test(e.message) ||
+/invalid arguments/.test(e.message))
+throw new RangeError('Could not instantiate buffer: size of buffer may be too large');
+else
+throw new Error('Could not instantiate buffer');
+}
+break;
+case 'string':
+// If string encode it and use buffer for the returned Uint8Array
+// to create a local patched version that acts like node buffer.
+encoding = encoding || 'utf8';
+return new Uint8Array(new TextEncoder(encoding).encode(subject).buffer);
+case 'object':
+// This form of the constructor uses the form of
+// new Uint8Array(buffer, offset, length);
+// So we can instantiate a typed array within the constructor
+// to inherit the appropriate properties, where both the
+// `subject` and newly instantiated buffer share the same underlying
+// data structure.
+if (arguments.length === 3)
+return new Uint8Array(subject, encoding, arguments[2]);
+// If array or alike just make a copy with a local patched prototype.
+else
+return new Uint8Array(subject);
+default:
+throw new TypeError('must start with number, buffer, array or string');
+}
+}
+exports.Buffer = Buffer;
+// Tests if `value` is a Buffer.
+Buffer.isBuffer = value => value instanceof Buffer
+// Returns true if the encoding is a valid encoding argument & false otherwise
+Buffer.isEncoding = function (encoding) {
+if (!encoding) return false;
+try {
+new TextDecoder(encoding);
+} catch(e) {
+return false;
+}
+return true;
+}
+// Gives the actual byte length of a string. encoding defaults to 'utf8'.
+// This is not the same as String.prototype.length since that returns the
+// number of characters in a string.
+Buffer.byteLength = (value, encoding = 'utf8') =>
+new TextEncoder(encoding).encode(value).byteLength
+// Direct copy of the nodejs's buffer implementation:
+// https://github.com/joyent/node/blob/b255f4c10a80343f9ce1cee56d0288361429e214/lib/buffer.js#L146-L177
+Buffer.concat = function(list, length) {
+if (!Array.isArray(list))
+throw new TypeError('Usage: Buffer.concat(list[, length])');
+if (typeof length === 'undefined') {
+length = 0;
+for (var i = 0; i < list.length; i++)
+length += list[i].length;
+} else {
+length = ~~length;
+}
+if (length < 0)
+length = 0;
+if (list.length === 0)
+return new Buffer(0);
+else if (list.length === 1)
+return list[0];
+if (length < 0)
+throw new RangeError('length is not a positive number');
+var buffer = new Buffer(length);
+var pos = 0;
+for (var i = 0; i < list.length; i++) {
+var buf = list[i];
+buf.copy(buffer, pos);
+pos += buf.length;
+}
+return buffer;
+};
+// Node buffer is very much like Uint8Array although it has bunch of methods
+// that typically can be used in combination with `DataView` while preserving
+// access by index. Since in SDK each module has it's own set of bult-ins it
+// ok to patch ours to make it nodejs Buffer compatible.
+Buffer.prototype = Uint8Array.prototype;
+Object.defineProperties(Buffer.prototype, {
+parent: {
+get: function() { return parents.get(this, undefined); }
+},
+view: {
+get: function () {
+let view = views.get(this, undefined);
+if (view) return view;
+view = new DataView(this.buffer);
+views.set(this, view);
+return view;
+}
+},
+toString: {
+value: function(encoding, start, end) {
+encoding = !!encoding ? (encoding + '').toLowerCase() : 'utf8';
+start = Math.max(0, ~~start);
+end = Math.min(this.length, end === void(0) ? this.length : ~~end);
+return new TextDecoder(encoding).decode(this.subarray(start, end));
+}
+},
+toJSON: {
+value: function() {
+return { type: 'Buffer', data: Array.slice(this, 0) };
+}
+},
+get: {
+value: function(offset) {
+return this[offset];
+}
+},
+set: {
+value: function(offset, value) { this[offset] = value; }
+},
+copy: {
+value: function(target, offset, start, end) {
+let length = this.length;
+let targetLength = target.length;
+offset = isNumber(offset) ? offset : 0;
+start = isNumber(start) ? start : 0;
+if (start < 0)
+throw new RangeError('sourceStart is outside of valid range');
+if (end < 0)
+throw new RangeError('sourceEnd is outside of valid range');
+// If sourceStart > sourceEnd, or targetStart > targetLength,
+// zero bytes copied
+if (start > end ||
+offset > targetLength
+)
+return 0;
+// If `end` is not defined, or if it is defined
+// but would overflow `target`, redefine `end`
+// so we can copy as much as we can
+if (end - start > targetLength - offset ||
+end == null) {
+let remainingTarget = targetLength - offset;
+let remainingSource = length - start;
+if (remainingSource <= remainingTarget)
+end = length;
+else
+end = start + remainingTarget;
+}
+Uint8Array.set(target, this.subarray(start, end), offset);
+return end - start;
+}
+},
+slice: {
+value: function(start, end) {
+let length = this.length;
+start = ~~start;
+end = end != null ? end : length;
+if (start < 0) {
+start += length;
+if (start < 0) start = 0;
+} else if (start > length)
+start = length;
+if (end < 0) {
+end += length;
+if (end < 0) end = 0;
+} else if (end > length)
+end = length;
+if (end < start)
+end = start;
+// This instantiation uses the new Uint8Array(buffer, offset, length) version
+// of construction to share the same underling data structure
+let buffer = new Buffer(this.buffer, start, end - start);
+// If buffer has a value, assign its parent value to the
+// buffer it shares its underlying structure with. If a slice of
+// a slice, then use the root structure
+if (buffer.length > 0)
+parents.set(buffer, this.parent || this);
+return buffer;
+}
+},
+write: {
+value: function(string, offset, length, encoding = 'utf8') {
+// write(string, encoding);
+if (typeof(offset) === 'string' && Number.isNaN(parseInt(offset))) {
+([offset, length, encoding]) = [0, null, offset];
+}
+// write(string, offset, encoding);
+else if (typeof(length) === 'string')
+([length, encoding]) = [null, length];
+if (offset < 0 || offset > this.length)
+throw new RangeError('offset is outside of valid range');
+offset = ~~offset;
+// Clamp length if it would overflow buffer, or if its
+// undefined
+if (length == null || length + offset > this.length)
+length = this.length - offset;
+let buffer = new TextEncoder(encoding).encode(string);
+let result = Math.min(buffer.length, length);
+if (buffer.length !== length)
+buffer = buffer.subarray(0, length);
+Uint8Array.set(this, buffer, offset);
+return result;
+}
+},
+fill: {
+value: function fill(value, start, end) {
+let length = this.length;
+value = value || 0;
+start = start || 0;
+end = end || length;
+if (typeof(value) === 'string')
+value = value.charCodeAt(0);
+if (typeof(value) !== 'number' || isNaN(value))
+throw TypeError('value is not a number');
+if (end < start)
+throw new RangeError('end < start');
+// Fill 0 bytes; we're done
+if (end === start)
+return 0;
+if (length == 0)
+return 0;
+if (start < 0 || start >= length)
+throw RangeError('start out of bounds');
+if (end < 0 || end > length)
+throw RangeError('end out of bounds');
+let index = start;
+while (index < end) this[index++] = value;
+}
+}
+});
+// Define nodejs Buffer's getter and setter functions that just proxy
+// to internal DataView's equivalent methods.
+// TODO do we need to check architecture to see if it's default big/little endian?
+[['readUInt16LE', 'getUint16', true],
+['readUInt16BE', 'getUint16', false],
+['readInt16LE', 'getInt16', true],
+['readInt16BE', 'getInt16', false],
+['readUInt32LE', 'getUint32', true],
+['readUInt32BE', 'getUint32', false],
+['readInt32LE', 'getInt32', true],
+['readInt32BE', 'getInt32', false],
+['readFloatLE', 'getFloat32', true],
+['readFloatBE', 'getFloat32', false],
+['readDoubleLE', 'getFloat64', true],
+['readDoubleBE', 'getFloat64', false],
+['readUInt8', 'getUint8'],
+['readInt8', 'getInt8']].forEach(([alias, name, littleEndian]) => {
+Object.defineProperty(Buffer.prototype, alias, {
+value: function(offset) this.view[name](offset, littleEndian)
+});
+});
+[['writeUInt16LE', 'setUint16', true],
+['writeUInt16BE', 'setUint16', false],
+['writeInt16LE', 'setInt16', true],
+['writeInt16BE', 'setInt16', false],
+['writeUInt32LE', 'setUint32', true],
+['writeUInt32BE', 'setUint32', false],
+['writeInt32LE', 'setInt32', true],
+['writeInt32BE', 'setInt32', false],
+['writeFloatLE', 'setFloat32', true],
+['writeFloatBE', 'setFloat32', false],
+['writeDoubleLE', 'setFloat64', true],
+['writeDoubleBE', 'setFloat64', false],
+['writeUInt8', 'setUint8'],
+['writeInt8', 'setInt8']].forEach(([alias, name, littleEndian]) => {
+Object.defineProperty(Buffer.prototype, alias, {
+value: function(value, offset) this.view[name](offset, value, littleEndian)
+});
+});