nodejs/test/parallel/test-fs-readfile-fd.js

97 lines
2.4 KiB
JavaScript

'use strict';
const common = require('../common');
// Test fs.readFile using a file descriptor.
const fixtures = require('../common/fixtures');
const assert = require('assert');
const fs = require('fs');
const fn = fixtures.path('empty.txt');
const join = require('path').join;
const tmpdir = require('../common/tmpdir');
tmpdir.refresh();
tempFd(function(fd, close) {
fs.readFile(fd, function(err, data) {
assert.ok(data);
close();
});
});
tempFd(function(fd, close) {
fs.readFile(fd, 'utf8', function(err, data) {
assert.strictEqual(data, '');
close();
});
});
tempFdSync(function(fd) {
assert.ok(fs.readFileSync(fd));
});
tempFdSync(function(fd) {
assert.strictEqual(fs.readFileSync(fd, 'utf8'), '');
});
function tempFd(callback) {
fs.open(fn, 'r', function(err, fd) {
assert.ifError(err);
callback(fd, function() {
fs.close(fd, function(err) {
assert.ifError(err);
});
});
});
}
function tempFdSync(callback) {
const fd = fs.openSync(fn, 'r');
callback(fd);
fs.closeSync(fd);
}
{
/*
* This test makes sure that `readFile()` always reads from the current
* position of the file, instead of reading from the beginning of the file,
* when used with file descriptors.
*/
const filename = join(tmpdir.path, 'test.txt');
fs.writeFileSync(filename, 'Hello World');
{
/* Tests the fs.readFileSync(). */
const fd = fs.openSync(filename, 'r');
/* Read only five bytes, so that the position moves to five. */
const buf = Buffer.alloc(5);
assert.deepStrictEqual(fs.readSync(fd, buf, 0, 5), 5);
assert.deepStrictEqual(buf.toString(), 'Hello');
/* readFileSync() should read from position five, instead of zero. */
assert.deepStrictEqual(fs.readFileSync(fd).toString(), ' World');
}
{
/* Tests the fs.readFile(). */
fs.open(filename, 'r', common.mustCall((err, fd) => {
assert.ifError(err);
const buf = Buffer.alloc(5);
/* Read only five bytes, so that the position moves to five. */
fs.read(fd, buf, 0, 5, null, common.mustCall((err, bytes) => {
assert.ifError(err);
assert.strictEqual(bytes, 5);
assert.deepStrictEqual(buf.toString(), 'Hello');
fs.readFile(fd, common.mustCall((err, data) => {
assert.ifError(err);
/* readFile() should read from position five, instead of zero. */
assert.deepStrictEqual(data.toString(), ' World');
}));
}));
}));
}
}