nodejs-mozilla/lib/v8.js

293 lines
9.1 KiB
JavaScript

// Copyright (c) 2014, StrongLoop Inc.
//
// Permission to use, copy, modify, and/or distribute this software for any
// purpose with or without fee is hereby granted, provided that the above
// copyright notice and this permission notice appear in all copies.
//
// THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
// WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
// MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
// ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
// WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
// ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
// OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
'use strict';
const {
Array,
ArrayBuffer,
Error,
Float32Array,
Float64Array,
Int16Array,
Int32Array,
Int8Array,
Map,
ObjectPrototypeToString,
Uint16Array,
Uint32Array,
Uint8Array,
Uint8ClampedArray,
} = primordials;
const { Buffer } = require('buffer');
const { validateString } = require('internal/validators');
const {
Serializer: _Serializer,
Deserializer: _Deserializer
} = internalBinding('serdes');
const assert = require('internal/assert');
const { copy } = internalBinding('buffer');
const { inspect } = require('internal/util/inspect');
const { FastBuffer } = require('internal/buffer');
const { getValidatedPath } = require('internal/fs/utils');
const { toNamespacedPath } = require('path');
const {
createHeapSnapshotStream,
triggerHeapSnapshot
} = internalBinding('heap_utils');
const { HeapSnapshotStream } = require('internal/heap_utils');
function writeHeapSnapshot(filename) {
if (filename !== undefined) {
filename = getValidatedPath(filename);
filename = toNamespacedPath(filename);
}
return triggerHeapSnapshot(filename);
}
function getHeapSnapshot() {
const handle = createHeapSnapshotStream();
assert(handle);
return new HeapSnapshotStream(handle);
}
// Calling exposed c++ functions directly throws exception as it expected to be
// called with new operator and caused an assert to fire.
// Creating JS wrapper so that it gets caught at JS layer.
class Serializer extends _Serializer { }
class Deserializer extends _Deserializer { }
const {
cachedDataVersionTag,
setFlagsFromString: _setFlagsFromString,
heapStatisticsArrayBuffer,
heapSpaceStatisticsArrayBuffer,
heapCodeStatisticsArrayBuffer,
updateHeapStatisticsArrayBuffer,
updateHeapSpaceStatisticsArrayBuffer,
updateHeapCodeStatisticsArrayBuffer,
// Properties for heap statistics buffer extraction.
kTotalHeapSizeIndex,
kTotalHeapSizeExecutableIndex,
kTotalPhysicalSizeIndex,
kTotalAvailableSize,
kUsedHeapSizeIndex,
kHeapSizeLimitIndex,
kDoesZapGarbageIndex,
kMallocedMemoryIndex,
kPeakMallocedMemoryIndex,
kNumberOfNativeContextsIndex,
kNumberOfDetachedContextsIndex,
// Properties for heap spaces statistics buffer extraction.
kHeapSpaces,
kHeapSpaceStatisticsPropertiesCount,
kSpaceSizeIndex,
kSpaceUsedSizeIndex,
kSpaceAvailableSizeIndex,
kPhysicalSpaceSizeIndex,
// Properties for heap code statistics buffer extraction.
kCodeAndMetadataSizeIndex,
kBytecodeAndMetadataSizeIndex,
kExternalScriptSourceSizeIndex
} = internalBinding('v8');
const kNumberOfHeapSpaces = kHeapSpaces.length;
const heapStatisticsBuffer =
new Float64Array(heapStatisticsArrayBuffer);
const heapSpaceStatisticsBuffer =
new Float64Array(heapSpaceStatisticsArrayBuffer);
const heapCodeStatisticsBuffer =
new Float64Array(heapCodeStatisticsArrayBuffer);
function setFlagsFromString(flags) {
validateString(flags, 'flags');
_setFlagsFromString(flags);
}
function getHeapStatistics() {
const buffer = heapStatisticsBuffer;
updateHeapStatisticsArrayBuffer();
return {
'total_heap_size': buffer[kTotalHeapSizeIndex],
'total_heap_size_executable': buffer[kTotalHeapSizeExecutableIndex],
'total_physical_size': buffer[kTotalPhysicalSizeIndex],
'total_available_size': buffer[kTotalAvailableSize],
'used_heap_size': buffer[kUsedHeapSizeIndex],
'heap_size_limit': buffer[kHeapSizeLimitIndex],
'malloced_memory': buffer[kMallocedMemoryIndex],
'peak_malloced_memory': buffer[kPeakMallocedMemoryIndex],
'does_zap_garbage': buffer[kDoesZapGarbageIndex],
'number_of_native_contexts': buffer[kNumberOfNativeContextsIndex],
'number_of_detached_contexts': buffer[kNumberOfDetachedContextsIndex]
};
}
function getHeapSpaceStatistics() {
const heapSpaceStatistics = new Array(kNumberOfHeapSpaces);
const buffer = heapSpaceStatisticsBuffer;
updateHeapSpaceStatisticsArrayBuffer();
for (let i = 0; i < kNumberOfHeapSpaces; i++) {
const propertyOffset = i * kHeapSpaceStatisticsPropertiesCount;
heapSpaceStatistics[i] = {
space_name: kHeapSpaces[i],
space_size: buffer[propertyOffset + kSpaceSizeIndex],
space_used_size: buffer[propertyOffset + kSpaceUsedSizeIndex],
space_available_size: buffer[propertyOffset + kSpaceAvailableSizeIndex],
physical_space_size: buffer[propertyOffset + kPhysicalSpaceSizeIndex]
};
}
return heapSpaceStatistics;
}
function getHeapCodeStatistics() {
const buffer = heapCodeStatisticsBuffer;
updateHeapCodeStatisticsArrayBuffer();
return {
'code_and_metadata_size': buffer[kCodeAndMetadataSizeIndex],
'bytecode_and_metadata_size': buffer[kBytecodeAndMetadataSizeIndex],
'external_script_source_size': buffer[kExternalScriptSourceSizeIndex]
};
}
/* V8 serialization API */
/* JS methods for the base objects */
Serializer.prototype._getDataCloneError = Error;
Deserializer.prototype.readRawBytes = function readRawBytes(length) {
const offset = this._readRawBytes(length);
// `this.buffer` can be a Buffer or a plain Uint8Array, so just calling
// `.slice()` doesn't work.
return new FastBuffer(this.buffer.buffer,
this.buffer.byteOffset + offset,
length);
};
/* Keep track of how to handle different ArrayBufferViews.
* The default Serializer for Node does not use the V8 methods for serializing
* those objects because Node's `Buffer` objects use pooled allocation in many
* cases, and their underlying `ArrayBuffer`s would show up in the
* serialization. Because a) those may contain sensitive data and the user
* may not be aware of that and b) they are often much larger than the `Buffer`
* itself, custom serialization is applied. */
const arrayBufferViewTypes = [Int8Array, Uint8Array, Uint8ClampedArray,
Int16Array, Uint16Array, Int32Array, Uint32Array,
Float32Array, Float64Array, DataView];
const arrayBufferViewTypeToIndex = new Map();
{
const dummy = new ArrayBuffer();
for (const [i, ctor] of arrayBufferViewTypes.entries()) {
const tag = ObjectPrototypeToString(new ctor(dummy));
arrayBufferViewTypeToIndex.set(tag, i);
}
}
const bufferConstructorIndex = arrayBufferViewTypes.push(FastBuffer) - 1;
class DefaultSerializer extends Serializer {
constructor() {
super();
this._setTreatArrayBufferViewsAsHostObjects(true);
}
_writeHostObject(abView) {
let i = 0;
if (abView.constructor === Buffer) {
i = bufferConstructorIndex;
} else {
const tag = ObjectPrototypeToString(abView);
i = arrayBufferViewTypeToIndex.get(tag);
if (i === undefined) {
throw new this._getDataCloneError(
`Unserializable host object: ${inspect(abView)}`);
}
}
this.writeUint32(i);
this.writeUint32(abView.byteLength);
this.writeRawBytes(new Uint8Array(abView.buffer,
abView.byteOffset,
abView.byteLength));
}
}
class DefaultDeserializer extends Deserializer {
_readHostObject() {
const typeIndex = this.readUint32();
const ctor = arrayBufferViewTypes[typeIndex];
const byteLength = this.readUint32();
const byteOffset = this._readRawBytes(byteLength);
const BYTES_PER_ELEMENT = ctor.BYTES_PER_ELEMENT || 1;
const offset = this.buffer.byteOffset + byteOffset;
if (offset % BYTES_PER_ELEMENT === 0) {
return new ctor(this.buffer.buffer,
offset,
byteLength / BYTES_PER_ELEMENT);
} else {
// Copy to an aligned buffer first.
const buffer_copy = Buffer.allocUnsafe(byteLength);
copy(this.buffer, buffer_copy, 0, byteOffset, byteOffset + byteLength);
return new ctor(buffer_copy.buffer,
buffer_copy.byteOffset,
byteLength / BYTES_PER_ELEMENT);
}
}
}
function serialize(value) {
const ser = new DefaultSerializer();
ser.writeHeader();
ser.writeValue(value);
return ser.releaseBuffer();
}
function deserialize(buffer) {
const der = new DefaultDeserializer(buffer);
der.readHeader();
return der.readValue();
}
module.exports = {
cachedDataVersionTag,
getHeapSnapshot,
getHeapStatistics,
getHeapSpaceStatistics,
getHeapCodeStatistics,
setFlagsFromString,
Serializer,
Deserializer,
DefaultSerializer,
DefaultDeserializer,
deserialize,
serialize,
writeHeapSnapshot,
};