diff --git a/lib/buffer.js b/lib/buffer.js index 2472390086057c..08575c10890c63 100644 --- a/lib/buffer.js +++ b/lib/buffer.js @@ -2,8 +2,14 @@ 'use strict'; const binding = process.binding('buffer'); +const { isArrayBuffer } = process.binding('util'); const bindingObj = {}; +class FastBuffer extends Uint8Array {} + +FastBuffer.prototype.constructor = Buffer; +Buffer.prototype = FastBuffer.prototype; + exports.Buffer = Buffer; exports.SlowBuffer = SlowBuffer; exports.INSPECT_MAX_BYTES = 50; @@ -62,12 +68,10 @@ Buffer.prototype.swap32 = function swap32() { const flags = bindingObj.flags; const kNoZeroFill = 0; -function createBuffer(size, noZeroFill) { - flags[kNoZeroFill] = noZeroFill ? 1 : 0; +function createUnsafeBuffer(size) { + flags[kNoZeroFill] = 1; try { - const ui8 = new Uint8Array(size); - Object.setPrototypeOf(ui8, Buffer.prototype); - return ui8; + return new FastBuffer(size); } finally { flags[kNoZeroFill] = 0; } @@ -75,7 +79,7 @@ function createBuffer(size, noZeroFill) { function createPool() { poolSize = Buffer.poolSize; - allocPool = createBuffer(poolSize, true); + allocPool = createUnsafeBuffer(poolSize); poolOffset = 0; } createPool(); @@ -133,7 +137,6 @@ Buffer.from = function(value, encodingOrOffset, length) { return fromObject(value); }; -Object.setPrototypeOf(Buffer.prototype, Uint8Array.prototype); Object.setPrototypeOf(Buffer, Uint8Array); function assertSize(size) { @@ -153,18 +156,16 @@ function assertSize(size) { **/ Buffer.alloc = function(size, fill, encoding) { assertSize(size); - if (size <= 0) - return createBuffer(size); - if (fill !== undefined) { + if (size > 0 && fill !== undefined) { // Since we are filling anyway, don't zero fill initially. // Only pay attention to encoding if it's a string. This // prevents accidentally sending in a number that would // be interpretted as a start offset. - return typeof encoding === 'string' ? - createBuffer(size, true).fill(fill, encoding) : - createBuffer(size, true).fill(fill); + if (typeof encoding !== 'string') + encoding = undefined; + return createUnsafeBuffer(size).fill(fill, encoding); } - return createBuffer(size); + return new FastBuffer(size); }; /** @@ -183,7 +184,7 @@ Buffer.allocUnsafe = function(size) { **/ Buffer.allocUnsafeSlow = function(size) { assertSize(size); - return createBuffer(size, true); + return createUnsafeBuffer(size); }; // If --zero-fill-buffers command line argument is set, a zero-filled @@ -191,7 +192,7 @@ Buffer.allocUnsafeSlow = function(size) { function SlowBuffer(length) { if (+length != length) length = 0; - return createBuffer(+length, true); + return createUnsafeBuffer(+length); } Object.setPrototypeOf(SlowBuffer.prototype, Uint8Array.prototype); @@ -200,7 +201,7 @@ Object.setPrototypeOf(SlowBuffer, Uint8Array); function allocate(size) { if (size <= 0) { - return createBuffer(0); + return new FastBuffer(); } if (size < (Buffer.poolSize >>> 1)) { if (size > (poolSize - poolOffset)) @@ -213,7 +214,7 @@ function allocate(size) { // Even though this is checked above, the conditional is a safety net and // sanity check to prevent any subsequent typed array allocation from not // being zero filled. - return createBuffer(size, true); + return createUnsafeBuffer(size); } } @@ -226,7 +227,7 @@ function fromString(string, encoding) { throw new TypeError('"encoding" must be a valid string encoding'); if (string.length === 0) - return Buffer.alloc(0); + return new FastBuffer(); var length = byteLength(string, encoding); @@ -246,18 +247,30 @@ function fromArrayLike(obj) { const length = obj.length; const b = allocate(length); for (var i = 0; i < length; i++) - b[i] = obj[i] & 255; + b[i] = obj[i]; return b; } function fromArrayBuffer(obj, byteOffset, length) { + if (!isArrayBuffer(obj)) + throw new TypeError('argument is not an ArrayBuffer'); + byteOffset >>>= 0; - if (typeof length === 'undefined') - return binding.createFromArrayBuffer(obj, byteOffset); + const maxLength = obj.byteLength - byteOffset; + + if (maxLength <= 0) + throw new RangeError("'offset' is out of bounds"); + + if (length === undefined) { + length = maxLength; + } else { + length >>>= 0; + if (length > maxLength) + throw new RangeError("'length' is out of bounds"); + } - length >>>= 0; - return binding.createFromArrayBuffer(obj, byteOffset, length); + return new FastBuffer(obj, byteOffset, length); } function fromObject(obj) { @@ -274,7 +287,7 @@ function fromObject(obj) { if (obj) { if (obj.buffer instanceof ArrayBuffer || 'length' in obj) { if (typeof obj.length !== 'number' || obj.length !== obj.length) { - return allocate(0); + return new FastBuffer(); } return fromArrayLike(obj); } @@ -341,7 +354,7 @@ Buffer.concat = function(list, length) { throw new TypeError('"list" argument must be an Array of Buffers'); if (list.length === 0) - return Buffer.alloc(0); + return new FastBuffer(); if (length === undefined) { length = 0; @@ -818,10 +831,26 @@ Buffer.prototype.toJSON = function() { }; +function adjustOffset(offset, length) { + offset = +offset; + if (offset === 0 || Number.isNaN(offset)) { + return 0; + } + if (offset < 0) { + offset += length; + return offset > 0 ? offset : 0; + } else { + return offset < length ? offset : length; + } +} + + Buffer.prototype.slice = function slice(start, end) { - const buffer = this.subarray(start, end); - Object.setPrototypeOf(buffer, Buffer.prototype); - return buffer; + const srcLength = this.length; + start = adjustOffset(start, srcLength); + end = end !== undefined ? adjustOffset(end, srcLength) : srcLength; + const newLength = end > start ? end - start : 0; + return new FastBuffer(this.buffer, this.byteOffset + start, newLength); }; diff --git a/src/node_buffer.cc b/src/node_buffer.cc index bb77387e8f87b7..345e6fe4c5b782 100644 --- a/src/node_buffer.cc +++ b/src/node_buffer.cc @@ -427,33 +427,6 @@ void CreateFromString(const FunctionCallbackInfo& args) { } -void CreateFromArrayBuffer(const FunctionCallbackInfo& args) { - Environment* env = Environment::GetCurrent(args); - if (!args[0]->IsArrayBuffer()) - return env->ThrowTypeError("argument is not an ArrayBuffer"); - Local ab = args[0].As(); - - size_t ab_length = ab->ByteLength(); - size_t offset; - size_t max_length; - - CHECK_NOT_OOB(ParseArrayIndex(args[1], 0, &offset)); - CHECK_NOT_OOB(ParseArrayIndex(args[2], ab_length - offset, &max_length)); - - if (offset >= ab_length) - return env->ThrowRangeError("'offset' is out of bounds"); - if (max_length > ab_length - offset) - return env->ThrowRangeError("'length' is out of bounds"); - - Local ui = Uint8Array::New(ab, offset, max_length); - Maybe mb = - ui->SetPrototype(env->context(), env->buffer_prototype_object()); - if (!mb.FromMaybe(false)) - return env->ThrowError("Unable to set Object prototype"); - args.GetReturnValue().Set(ui); -} - - template void StringSlice(const FunctionCallbackInfo& args) { Environment* env = Environment::GetCurrent(args); @@ -1246,7 +1219,6 @@ void Initialize(Local target, env->SetMethod(target, "setupBufferJS", SetupBufferJS); env->SetMethod(target, "createFromString", CreateFromString); - env->SetMethod(target, "createFromArrayBuffer", CreateFromArrayBuffer); env->SetMethod(target, "byteLengthUtf8", ByteLengthUtf8); env->SetMethod(target, "compare", Compare);