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fs: Fix default params for fs.write(Sync)
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Add support for fs.write(fd, buffer, cb) and fs.write(fd, buffer, offset, cb)
as documented at
https://nodejs.org/api/fs.html#fs_fs_write_fd_data_position_encoding_callback
and equivalently for fs.writeSync

Update docs and code comments to reflect the implementation.

PR-URL: #7856
Reviewed-By: Sam Roberts <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Brian White <[email protected]>
Reviewed-By: Yorkie Liu <[email protected]>
Reviewed-By: Gibson Fahnestock <[email protected]>
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papandreou authored and Fishrock123 committed Nov 22, 2016
1 parent bbd5853 commit 8a9c45a
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Showing 4 changed files with 171 additions and 52 deletions.
20 changes: 10 additions & 10 deletions doc/api/fs.md
Original file line number Diff line number Diff line change
Expand Up @@ -1816,13 +1816,13 @@ _Note: [`fs.watch()`][] is more efficient than `fs.watchFile` and
`fs.unwatchFile`. `fs.watch` should be used instead of `fs.watchFile` and
`fs.unwatchFile` when possible._

## fs.write(fd, buffer, offset, length[, position], callback)
## fs.write(fd, buffer[, offset[, length[, position]]], callback)
<!-- YAML
added: v0.0.2
-->

* `fd` {Integer}
* `buffer` {String | Buffer}
* `buffer` {Buffer}
* `offset` {Integer}
* `length` {Integer}
* `position` {Integer}
Expand All @@ -1847,19 +1847,19 @@ On Linux, positional writes don't work when the file is opened in append mode.
The kernel ignores the position argument and always appends the data to
the end of the file.

## fs.write(fd, data[, position[, encoding]], callback)
## fs.write(fd, string[, position[, encoding]], callback)
<!-- YAML
added: v0.11.5
-->

* `fd` {Integer}
* `data` {String | Buffer}
* `string` {String}
* `position` {Integer}
* `encoding` {String}
* `callback` {Function}

Write `data` to the file specified by `fd`. If `data` is not a Buffer instance
then the value will be coerced to a string.
Write `string` to the file specified by `fd`. If `string` is not a string, then
the value will be coerced to one.

`position` refers to the offset from the beginning of the file where this data
should be written. If `typeof position !== 'number'` the data will be written at
Expand Down Expand Up @@ -1940,24 +1940,24 @@ added: v0.1.29

The synchronous version of [`fs.writeFile()`][]. Returns `undefined`.

## fs.writeSync(fd, buffer, offset, length[, position])
## fs.writeSync(fd, buffer[, offset[, length[, position]]])
<!-- YAML
added: v0.1.21
-->

* `fd` {Integer}
* `buffer` {String | Buffer}
* `buffer` {Buffer}
* `offset` {Integer}
* `length` {Integer}
* `position` {Integer}

## fs.writeSync(fd, data[, position[, encoding]])
## fs.writeSync(fd, string[, position[, encoding]])
<!-- YAML
added: v0.11.5
-->

* `fd` {Integer}
* `data` {String | Buffer}
* `string` {String}
* `position` {Integer}
* `encoding` {String}

Expand Down
20 changes: 14 additions & 6 deletions lib/fs.js
Original file line number Diff line number Diff line change
Expand Up @@ -662,7 +662,7 @@ fs.readSync = function(fd, buffer, offset, length, position) {
};

// usage:
// fs.write(fd, buffer, offset, length[, position], callback);
// fs.write(fd, buffer[, offset[, length[, position]]], callback);
// OR
// fs.write(fd, string[, position[, encoding]], callback);
fs.write = function(fd, buffer, offset, length, position, callback) {
Expand All @@ -675,12 +675,16 @@ fs.write = function(fd, buffer, offset, length, position, callback) {
req.oncomplete = wrapper;

if (buffer instanceof Buffer) {
// if no position is passed then assume null
if (typeof position === 'function') {
callback = position;
callback = maybeCallback(callback || position || length || offset);
if (typeof offset !== 'number') {
offset = 0;
}
if (typeof length !== 'number') {
length = buffer.length - offset;
}
if (typeof position !== 'number') {
position = null;
}
callback = maybeCallback(callback);
return binding.writeBuffer(fd, buffer, offset, length, position, req);
}

Expand All @@ -700,13 +704,17 @@ fs.write = function(fd, buffer, offset, length, position, callback) {
};

// usage:
// fs.writeSync(fd, buffer, offset, length[, position]);
// fs.writeSync(fd, buffer[, offset[, length[, position]]]);
// OR
// fs.writeSync(fd, string[, position[, encoding]]);
fs.writeSync = function(fd, buffer, offset, length, position) {
if (buffer instanceof Buffer) {
if (position === undefined)
position = null;
if (typeof offset !== 'number')
offset = 0;
if (typeof length !== 'number')
length = buffer.length - offset;
return binding.writeBuffer(fd, buffer, offset, length, position);
}
if (typeof buffer !== 'string')
Expand Down
120 changes: 99 additions & 21 deletions test/parallel/test-fs-write-buffer.js
Original file line number Diff line number Diff line change
Expand Up @@ -2,29 +2,107 @@
const common = require('../common');
const assert = require('assert');
const path = require('path');
const Buffer = require('buffer').Buffer;
const fs = require('fs');
const filename = path.join(common.tmpDir, 'write.txt');
const expected = Buffer.from('hello');

common.refreshTmpDir();

fs.open(filename, 'w', 0o644, common.mustCall(function(err, fd) {
if (err) throw err;

fs.write(fd,
expected,
0,
expected.length,
null,
common.mustCall(function(err, written) {
if (err) throw err;

assert.equal(expected.length, written);
fs.closeSync(fd);

var found = fs.readFileSync(filename, 'utf8');
assert.deepStrictEqual(expected.toString(), found);
fs.unlinkSync(filename);
}));
}));
// fs.write with all parameters provided:
{
const filename = path.join(common.tmpDir, 'write1.txt');
fs.open(filename, 'w', 0o644, common.mustCall(function(err, fd) {
assert.ifError(err);

const cb = common.mustCall(function(err, written) {
assert.ifError(err);

assert.strictEqual(expected.length, written);
fs.closeSync(fd);

var found = fs.readFileSync(filename, 'utf8');
assert.deepStrictEqual(expected.toString(), found);
});

fs.write(fd, expected, 0, expected.length, null, cb);
}));
}

// fs.write with a buffer, without the length parameter:
{
const filename = path.join(common.tmpDir, 'write2.txt');
fs.open(filename, 'w', 0o644, common.mustCall(function(err, fd) {
assert.ifError(err);

const cb = common.mustCall(function(err, written) {
assert.ifError(err);

assert.strictEqual(2, written);
fs.closeSync(fd);

const found = fs.readFileSync(filename, 'utf8');
assert.deepStrictEqual('lo', found);
});

fs.write(fd, Buffer.from('hello'), 3, cb);
}));
}

// fs.write with a buffer, without the offset and length parameters:
{
const filename = path.join(common.tmpDir, 'write3.txt');
fs.open(filename, 'w', 0o644, common.mustCall(function(err, fd) {
assert.ifError(err);

const cb = common.mustCall(function(err, written) {
assert.ifError(err);

assert.strictEqual(expected.length, written);
fs.closeSync(fd);

const found = fs.readFileSync(filename, 'utf8');
assert.deepStrictEqual(expected.toString(), found);
});

fs.write(fd, expected, cb);
}));
}

// fs.write with the offset passed as undefined followed by the callback:
{
const filename = path.join(common.tmpDir, 'write4.txt');
fs.open(filename, 'w', 0o644, common.mustCall(function(err, fd) {
assert.ifError(err);

const cb = common.mustCall(function(err, written) {
assert.ifError(err);

assert.strictEqual(expected.length, written);
fs.closeSync(fd);

const found = fs.readFileSync(filename, 'utf8');
assert.deepStrictEqual(expected.toString(), found);
});

fs.write(fd, expected, undefined, cb);
}));
}

// fs.write with offset and length passed as undefined followed by the callback:
{
const filename = path.join(common.tmpDir, 'write5.txt');
fs.open(filename, 'w', 0o644, common.mustCall(function(err, fd) {
assert.ifError(err);

const cb = common.mustCall(function(err, written) {
assert.ifError(err);

assert.strictEqual(expected.length, written);
fs.closeSync(fd);

const found = fs.readFileSync(filename, 'utf8');
assert.deepStrictEqual(expected.toString(), found);
});

fs.write(fd, expected, undefined, undefined, cb);
}));
}
63 changes: 48 additions & 15 deletions test/parallel/test-fs-write-sync.js
Original file line number Diff line number Diff line change
@@ -1,23 +1,56 @@
'use strict';
var common = require('../common');
var assert = require('assert');
var path = require('path');
var fs = require('fs');
var fn = path.join(common.tmpDir, 'write.txt');
const common = require('../common');
const assert = require('assert');
const path = require('path');
const fs = require('fs');
const filename = path.join(common.tmpDir, 'write.txt');

common.refreshTmpDir();

var foo = 'foo';
var fd = fs.openSync(fn, 'w');
// fs.writeSync with all parameters provided:
{
const fd = fs.openSync(filename, 'w');

var written = fs.writeSync(fd, '');
assert.strictEqual(0, written);
let written = fs.writeSync(fd, '');
assert.strictEqual(0, written);

fs.writeSync(fd, foo);
fs.writeSync(fd, 'foo');

var bar = 'bár';
written = fs.writeSync(fd, Buffer.from(bar), 0, Buffer.byteLength(bar));
assert.ok(written > 3);
fs.closeSync(fd);
written = fs.writeSync(fd, Buffer.from('bár'), 0, Buffer.byteLength('bár'));
assert.ok(written > 3);
fs.closeSync(fd);

assert.equal(fs.readFileSync(fn), 'foobár');
assert.strictEqual(fs.readFileSync(filename, 'utf-8'), 'foobár');
}

// fs.writeSync with a buffer, without the length parameter:
{
const fd = fs.openSync(filename, 'w');

let written = fs.writeSync(fd, '');
assert.strictEqual(0, written);

fs.writeSync(fd, 'foo');

written = fs.writeSync(fd, Buffer.from('bár'), 0);
assert.ok(written > 3);
fs.closeSync(fd);

assert.strictEqual(fs.readFileSync(filename, 'utf-8'), 'foobár');
}

// fs.writeSync with a buffer, without the offset and length parameters:
{
const fd = fs.openSync(filename, 'w');

let written = fs.writeSync(fd, '');
assert.strictEqual(0, written);

fs.writeSync(fd, 'foo');

written = fs.writeSync(fd, Buffer.from('bár'));
assert.ok(written > 3);
fs.closeSync(fd);

assert.strictEqual(fs.readFileSync(filename, 'utf-8'), 'foobár');
}

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