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add positioned writing feature to fs.WriteStream #1645

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@@ -493,3 +493,8 @@ 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`.
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@@ -928,10 +928,10 @@ var ReadStream = fs.ReadStream = function(path, options) {
}
if (this.start > this.end) {
- this.emit('error', new Error('start must be <= end'));
- } else {
- this._firstRead = true;
+ throw new Error('start must be <= end');
}
+
+ this.pos = this.start;
}
if (this.fd !== null) {
@@ -962,9 +962,9 @@ ReadStream.prototype.setEncoding = function(encoding) {
ReadStream.prototype._read = function() {
var self = this;
- if (!self.readable || self.paused || self.reading) return;
+ if (!this.readable || this.paused || this.reading) return;
- self.reading = true;
+ this.reading = true;
if (!pool || pool.length - pool.used < kMinPoolSpace) {
// discard the old pool. Can't add to the free list because
@@ -973,11 +973,6 @@ ReadStream.prototype._read = function() {
allocNewPool();
}
- if (self.start !== undefined && self._firstRead) {
- self.pos = self.start;
- self._firstRead = false;
- }
-
// Grab another reference to the pool in the case that while we're in the
// thread pool another read() finishes up the pool, and allocates a new
// one.
@@ -1022,10 +1017,10 @@ ReadStream.prototype._read = function() {
self._read();
}
- fs.read(self.fd, pool, pool.used, toRead, self.pos, afterRead);
+ fs.read(this.fd, pool, pool.used, toRead, this.pos, afterRead);
- if (self.pos !== undefined) {
- self.pos += toRead;
+ if (this.pos !== undefined) {
+ this.pos += toRead;
}
pool.used += toRead;
};
@@ -1114,6 +1109,14 @@ 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 = [];
@@ -1132,7 +1135,7 @@ WriteStream.prototype.flush = function() {
var args = this._queue.shift();
if (!args) {
- if (this.drainable) { self.emit('drain'); }
+ if (this.drainable) { this.emit('drain'); }
return;
}
@@ -1141,8 +1144,6 @@ WriteStream.prototype.flush = function() {
var method = args.shift(),
cb = args.pop();
- var self = this;
-
args.push(function(err) {
self.busy = false;
@@ -1157,40 +1158,39 @@ WriteStream.prototype.flush = function() {
if (method == fs.write) {
self.bytesWritten += arguments[1];
- }
+ if (cb) {
+ // write callback
+ cb(null, arguments[1]);
+ }
+
+ } else if (method === fs.open) {
+ // save reference for file pointer
+ self.fd = arguments[1];
+ self.emit('open', self.fd);
- // stop flushing after close
- if (method === fs.close) {
+ } else if (method === fs.close) {
+ // stop flushing after close
if (cb) {
cb(null);
}
self.emit('close');
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();
});
// Inject the file pointer
if (method !== fs.open) {
- args.unshift(self.fd);
+ args.unshift(this.fd);
}
method.apply(this, args);
};
WriteStream.prototype.write = function(data) {
if (!this.writable) {
- this.emit("error", new Error('stream not writable'));
+ this.emit('error', new Error('stream not writable'));
return false;
}
@@ -1201,14 +1201,17 @@ 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();
@@ -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 ';
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