electron/lib/common/buffer-utils.js
Thiago de Arruda 6ff111a141 perf: don't use JSON to send the result of ipcRenderer.sendSync. (#8953)
* Don't use JSON to send the result of `ipcRenderer.sendSync`.

- Change the return type of AtomViewHostMsg_Message_Sync from `base::string16`
  to `base::ListValue`
- Adjust lib/browser/api/web-contents.js and /lib/renderer/api/ipc-renderer.js
  to wrap/unwrap return values to/from array, instead of
  serializing/deserializing JSON.

This change can greatly improve `ipcRenderer.sendSync` calls where the return
value contains Buffer instances, because those are converted to Array before
being serialized to JSON(which has no efficient way of representing byte
arrays).

A simple benchmark where remote.require('fs') was used to read a 16mb file got
at least 5x faster, not to mention it used a lot less memory.  This difference
tends increases with larger buffers.

* Don't base64 encode Buffers

* Don't allocate V8ValueConverter on the heap

* Replace hidden global.sandbox with NodeBindings::IsInitialized()

* Refactoring: check NodeBindings::IsInitialized() in V8ValueConverter

* Refactor problematic test to make it more reliable

* Add tests for NaN and Infinity
2018-06-13 17:38:31 +10:00

64 lines
1.4 KiB
JavaScript

// Note: Don't use destructuring assignment for `Buffer`, or we'll hit a
// browserify bug that makes the statement invalid, throwing an error in
// sandboxed renderer.
const Buffer = require('buffer').Buffer
const typedArrays = {
Buffer,
ArrayBuffer,
Int8Array,
Uint8Array,
Uint8ClampedArray,
Int16Array,
Uint16Array,
Int32Array,
Uint32Array,
Float32Array,
Float64Array
}
function getType (value) {
for (const type of Object.keys(typedArrays)) {
if (value instanceof typedArrays[type]) {
return type
}
}
return null
}
function getBuffer (value) {
if (value instanceof Buffer) {
return value
} else if (value instanceof ArrayBuffer) {
return Buffer.from(value)
} else {
return Buffer.from(value.buffer, value.byteOffset, value.byteLength)
}
}
exports.isBuffer = function (value) {
return ArrayBuffer.isView(value) || value instanceof ArrayBuffer
}
exports.bufferToMeta = function (value) {
return {
type: getType(value),
data: getBuffer(value),
length: value.length
}
}
exports.metaToBuffer = function (value) {
const constructor = typedArrays[value.type]
const data = getBuffer(value.data)
if (constructor === Buffer) {
return data
} else if (constructor === ArrayBuffer) {
return data.buffer
} else if (constructor) {
return new constructor(data.buffer, data.byteOffset, value.length)
} else {
return data
}
}