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fs: add positioned file writing feature to fs.WriteStream

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Patterned on same feature in ReadStream; a small bit of new code added
plus two refactorings of previous code; added two test files.

Fixes #1645.
This commit is contained in:
Thomas Shinnick 2011-09-11 15:30:01 -05:00 committed by koichik
parent e4ebeb630e
commit e58c036c27
4 changed files with 335 additions and 16 deletions
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5
doc/api/fs.markdown
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@ -496,3 +496,8 @@ Returns a new WriteStream object (See `Writable Stream`).
{ flags: 'w',
encoding: null,
mode: 0666 }
`options` may also include a `start` option to allow writing data at
some position past the beginning of the file. Modifying a file rather
than replacing it may require a `flags` mode of `r+` rather than the
default mode `w`.

42
lib/fs.js
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@ -1112,6 +1112,14 @@ var WriteStream = fs.WriteStream = function(path, options) {
this[key] = options[key];
}
if (this.start !== undefined) {
if (this.start < 0) {
throw new Error('start must be >= zero');
}
this.pos = this.start;
}
this.busy = false;
this._queue = [];
@ -1153,10 +1161,18 @@ WriteStream.prototype.flush = function() {
if (method == fs.write) {
self.bytesWritten += arguments[1];
}
if (cb) {
// write callback
cb(null, arguments[1]);
}
// stop flushing after close
if (method === fs.close) {
} else if (method === fs.open) {
// save reference for file pointer
self.fd = arguments[1];
self.emit('open', self.fd);
} else if (method === fs.close) {
// stop flushing after close
if (cb) {
cb(null);
}
@ -1164,15 +1180,6 @@ WriteStream.prototype.flush = function() {
return;
}
// save reference for file pointer
if (method === fs.open) {
self.fd = arguments[1];
self.emit('open', self.fd);
} else if (cb) {
// write callback
cb(null, arguments[1]);
}
self.flush();
});
@ -1197,14 +1204,17 @@ WriteStream.prototype.write = function(data) {
cb = arguments[arguments.length - 1];
}
if (Buffer.isBuffer(data)) {
this._queue.push([fs.write, data, 0, data.length, null, cb]);
} else {
if (!Buffer.isBuffer(data)) {
var encoding = 'utf8';
if (typeof(arguments[1]) == 'string') encoding = arguments[1];
this._queue.push([fs.write, data, undefined, encoding, cb]);
data = new Buffer('' + data, encoding);
}
this._queue.push([fs.write, data, 0, data.length, this.pos, cb]);
if (this.pos !== undefined) {
this.pos += data.length;
}
this.flush();

98
test/simple/test-file-write-stream2.js Normal file
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@ -0,0 +1,98 @@
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
var common = require('../common');
var assert = require('assert');
var path = require('path'),
fs = require('fs'),
util = require('util');
var filepath = path.join(common.tmpDir, 'write.txt'),
file;
var EXPECTED = '012345678910';
var cb_expected = 'write open drain write drain close error ',
cb_occurred = '';
var countDrains = 0;
process.on('exit', function() {
removeTestFile();
if ( cb_occurred !== cb_expected) {
console.log(' Test callback events missing or out of order:');
console.log(' expected: %j', cb_expected);
console.log(' occurred: %j', cb_occurred);
assert.strictEqual(cb_occurred, cb_expected,
'events missing or out of order: "' +
cb_occurred + '" !== "' + cb_expected + '"');
}
});
function removeTestFile() {
try {
fs.unlinkSync(filepath);
} catch (e) {}
}
removeTestFile();
file = fs.createWriteStream(filepath);
file.on('open', function(fd) {
cb_occurred += 'open ';
assert.equal(typeof fd, 'number');
});
file.on('drain', function() {
cb_occurred += 'drain ';
++countDrains;
if (countDrains === 1) {
assert.equal(fs.readFileSync(filepath), EXPECTED);
file.write(EXPECTED);
cb_occurred += 'write ';
} else if (countDrains == 2) {
assert.equal(fs.readFileSync(filepath), EXPECTED + EXPECTED);
file.end();
}
});
file.on('close', function() {
cb_occurred += 'close ';
assert.strictEqual(file.bytesWritten, EXPECTED.length * 2);
file.write('should not work anymore');
});
file.on('error', function(err) {
cb_occurred += 'error ';
assert.ok(err.message.indexOf('not writable') >= 0);
});
for (var i = 0; i < 11; i++) {
assert.strictEqual(file.write(i), false);
}
cb_occurred += 'write ';

206
test/simple/test-file-write-stream3.js Normal file
View File

@ -0,0 +1,206 @@
// Copyright Joyent, Inc. and other Node contributors.
//
// Permission is hereby granted, free of charge, to any person obtaining a
// copy of this software and associated documentation files (the
// "Software"), to deal in the Software without restriction, including
// without limitation the rights to use, copy, modify, merge, publish,
// distribute, sublicense, and/or sell copies of the Software, and to permit
// persons to whom the Software is furnished to do so, subject to the
// following conditions:
//
// The above copyright notice and this permission notice shall be included
// in all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
// USE OR OTHER DEALINGS IN THE SOFTWARE.
var common = require('../common');
var assert = require('assert');
var path = require('path'),
fs = require('fs'),
util = require('util');
var filepath = path.join(common.tmpDir, 'write_pos.txt');
var cb_expected = 'write open close write open close write open close ',
cb_occurred = '';
var fileDataInitial = 'abcdefghijklmnopqrstuvwxyz';
var fileDataExpected_1 = 'abcdefghijklmnopqrstuvwxyz';
var fileDataExpected_2 = 'abcdefghij123456qrstuvwxyz';
var fileDataExpected_3 = 'abcdefghij\u2026\u2026qrstuvwxyz';
process.on('exit', function() {
removeTestFile();
if ( cb_occurred !== cb_expected) {
console.log(' Test callback events missing or out of order:');
console.log(' expected: %j', cb_expected);
console.log(' occurred: %j', cb_occurred);
assert.strictEqual(cb_occurred, cb_expected,
'events missing or out of order: "' +
cb_occurred + '" !== "' + cb_expected + '"');
}
});
function removeTestFile() {
try {
fs.unlinkSync(filepath);
} catch (ex) { }
}
removeTestFile();
function run_test_1() {
var file, buffer, options;
options = {};
file = fs.createWriteStream(filepath, options);
console.log(' (debug: start ', file.start);
console.log(' (debug: pos ', file.pos);
file.on('open', function(fd) {
cb_occurred += 'open ';
});
file.on('close', function() {
cb_occurred += 'close ';
console.log(' (debug: bytesWritten ', file.bytesWritten);
console.log(' (debug: start ', file.start);
console.log(' (debug: pos ', file.pos);
assert.strictEqual(file.bytesWritten, buffer.length);
var fileData = fs.readFileSync(filepath, 'utf8');
console.log(' (debug: file data ', fileData);
console.log(' (debug: expected ', fileDataExpected_1);
assert.equal(fileData, fileDataExpected_1);
run_test_2();
});
file.on('error', function(err) {
cb_occurred += 'error ';
console.log(' (debug: err event ', err);
throw err;
});
buffer = new Buffer(fileDataInitial);
file.write(buffer);
cb_occurred += 'write ';
file.end();
}
function run_test_2() {
var file, buffer, options;
buffer = new Buffer('123456');
options = { start: 10,
flags: 'r+' };
file = fs.createWriteStream(filepath, options);
console.log(' (debug: start ', file.start);
console.log(' (debug: pos ', file.pos);
file.on('open', function(fd) {
cb_occurred += 'open ';
});
file.on('close', function() {
cb_occurred += 'close ';
console.log(' (debug: bytesWritten ', file.bytesWritten);
console.log(' (debug: start ', file.start);
console.log(' (debug: pos ', file.pos);
assert.strictEqual(file.bytesWritten, buffer.length);
var fileData = fs.readFileSync(filepath, 'utf8');
console.log(' (debug: file data ', fileData);
console.log(' (debug: expected ', fileDataExpected_2);
assert.equal(fileData, fileDataExpected_2);
run_test_3();
});
file.on('error', function(err) {
cb_occurred += 'error ';
console.log(' (debug: err event ', err);
throw err;
});
file.write(buffer);
cb_occurred += 'write ';
file.end();
}
function run_test_3() {
var file, buffer, options;
var data = '\u2026\u2026', // 3 bytes * 2 = 6 bytes in UTF-8
fileData;
options = { start: 10,
flags: 'r+' };
file = fs.createWriteStream(filepath, options);
console.log(' (debug: start ', file.start);
console.log(' (debug: pos ', file.pos);
file.on('open', function(fd) {
cb_occurred += 'open ';
});
file.on('close', function() {
cb_occurred += 'close ';
console.log(' (debug: bytesWritten ', file.bytesWritten);
console.log(' (debug: start ', file.start);
console.log(' (debug: pos ', file.pos);
assert.strictEqual(file.bytesWritten, data.length * 3);
fileData = fs.readFileSync(filepath, 'utf8');
console.log(' (debug: file data ', fileData);
console.log(' (debug: expected ', fileDataExpected_3);
assert.equal(fileData, fileDataExpected_3);
run_test_4();
});
file.on('error', function(err) {
cb_occurred += 'error ';
console.log(' (debug: err event ', err);
throw err;
});
file.write(data, 'utf8');
cb_occurred += 'write ';
file.end();
}
function run_test_4() {
var file, options;
options = { start: -5,
flags: 'r+' };
// Error: start must be >= zero
assert.throws(
function() {
file = fs.createWriteStream(filepath, options);
},
/start must be/
);
}
run_test_1();