pointer.js
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var assert = require('assert')
var weak = require('weak')
var ref = require('../')
describe('pointer', function () {
var test = new Buffer('hello world')
beforeEach(gc)
it('should write and read back a pointer (Buffer) in a Buffer', function () {
var buf = new Buffer(ref.sizeof.pointer)
ref.writePointer(buf, 0, test)
var out = ref.readPointer(buf, 0, test.length)
assert.strictEqual(out.length, test.length)
for (var i = 0, l = out.length; i < l; i++) {
assert.strictEqual(out[i], test[i])
}
assert.strictEqual(ref.address(out), ref.address(test))
})
it('should retain references to a written pointer in a Buffer', function (done) {
var child_gc = false
var parent_gc = false
var child = new Buffer('a pointer holding some data...')
var parent = new Buffer(ref.sizeof.pointer)
weak(child, function () { child_gc = true })
weak(parent, function () { parent_gc = true })
ref.writePointer(parent, 0, child)
assert(!child_gc, '"child" has been garbage collected too soon')
assert(!parent_gc, '"parent" has been garbage collected too soon')
// try to GC `child`
child = null
gc()
assert(!child_gc, '"child" has been garbage collected too soon')
assert(!parent_gc, '"parent" has been garbage collected too soon')
// now GC `parent`
parent = null
setImmediate(function () {
gc()
assert(parent_gc, '"parent" has not been garbage collected')
assert(child_gc, '"child" has not been garbage collected')
done()
});
})
it('should throw an Error when reading from the NULL pointer', function () {
assert.throws(function () {
ref.NULL.readPointer()
})
})
it('should return a 0-length Buffer when reading a NULL pointer', function () {
var buf = new Buffer(ref.sizeof.pointer)
ref.writePointer(buf, 0, ref.NULL)
var out = ref.readPointer(buf, 0, 100)
assert.strictEqual(out.length, 0)
})
describe('offset', function () {
it('should read two pointers next to each other in memory', function () {
var buf = new Buffer(ref.sizeof.pointer * 2)
var a = new Buffer('hello')
var b = new Buffer('world')
buf.writePointer(a, 0 * ref.sizeof.pointer)
buf.writePointer(b, 1 * ref.sizeof.pointer)
var _a = buf.readPointer(0 * ref.sizeof.pointer)
var _b = buf.readPointer(1 * ref.sizeof.pointer)
assert.equal(a.address(), _a.address())
assert.equal(b.address(), _b.address())
})
})
})