fs: add appendFile() and appendFileSync() functions

doc/api/fs.markdown

@@ -387,6 +387,23 @@ Example:
 
 The synchronous version of `fs.writeFile`.
 
+### fs.appendFile(filename, data, encoding='utf8', [callback])
+
+Asynchronously append data to a file, creating the file if it not yet exists.
+`data` can be a string or a buffer. The `encoding` argument is ignored if
+`data` is a buffer.
+
+Example:
+
+    fs.appendFile('message.txt', 'data to append', function (err) {
+      if (err) throw err;
+      console.log('The "data to append" was appended to file!');
+    });
+
+### fs.appendFileSync(filename, data, encoding='utf8')
+
+The synchronous version of `fs.appendFile`.
+
 ### fs.watchFile(filename, [options], listener)
 
 Watch for changes on `filename`. The callback `listener` will be called each

lib/fs.js

@@ -582,9 +582,12 @@ fs.futimesSync = function(fd, atime, mtime) {
   binding.futimes(fd, atime, mtime);
 };
 
-function writeAll(fd, buffer, offset, length, callback) {
+function writeAll(fd, buffer, offset, length, position, callback) {
+  var callback_ = arguments[arguments.length - 1];
+  callback = (typeof(callback_) == 'function' ? callback_ : null);
+
   // write(fd, buffer, offset, length, position, callback)
-  fs.write(fd, buffer, offset, length, offset, function(writeErr, written) {
+  fs.write(fd, buffer, offset, length, position, function(writeErr, written) {
     if (writeErr) {
       fs.close(fd, function() {
         if (callback) callback(writeErr);
@@ -593,7 +596,7 @@ function writeAll(fd, buffer, offset, length, callback) {
       if (written === length) {
         fs.close(fd, callback);
       } else {
-        writeAll(fd, buffer, offset + written, length - written, callback);
+        writeAll(fd, buffer, offset + written, length - written, position + written, callback);
       }
     }
   });
@@ -609,7 +612,7 @@ fs.writeFile = function(path, data, encoding_, callback) {
     } else {
       var buffer = Buffer.isBuffer(data) ? data : new Buffer('' + data,
           encoding);
-      writeAll(fd, buffer, 0, buffer.length, callback);
+      writeAll(fd, buffer, 0, buffer.length, 0, callback);
     }
   });
 };
@@ -628,6 +631,42 @@ fs.writeFileSync = function(path, data, encoding) {
   fs.closeSync(fd);
 };
 
+fs.appendFile = function(path, data, encoding_, callback) {
+  var encoding = (typeof(encoding_) == 'string' ? encoding_ : 'utf8');
+  var callback_ = arguments[arguments.length - 1];
+  callback = (typeof(callback_) == 'function' ? callback_ : null);
+
+  fs.open(path, 'a', 438 /*=0666*/, function(err, fd) {
+    if (err) return callback(err);
+    var buffer = Buffer.isBuffer(data) ? data : new Buffer('' + data, encoding);
+    writeAll(fd, buffer, 0, buffer.length, null, callback);
+  });
+};
+
+fs.appendFileSync = function(path, data, encoding) {
+  var fd = fs.openSync(path, 'a');
+  if (!Buffer.isBuffer(data)) {
+    data = new Buffer('' + data, encoding || 'utf8');
+  }
+  var written = 0;
+  var position = null;
+  var length = data.length;
+
+  while (written < length) {
+    try {
+      written += fs.writeSync(fd, data, written, length - written, position);
+    } catch (e) {
+      try {
+        fs.closeSync(fd);
+      } catch (e) {
+        // swallow exception
+      }
+      throw e;
+    }
+    position += written;
+  }
+  fs.closeSync(fd);
+};
 
 function errnoException(errorno, syscall) {
   // TODO make this more compatible with ErrnoException from src/node.cc

test/simple/test-fs-append-file-sync.js

@@ -0,0 +1,92 @@
+// 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 join = require('path').join;
+var fs = require('fs');
+
+var currentFileData = 'ABCD';
+
+var num = 220;
+var data = '南越国是前203年至前111年存在于岭南地区的一个国家，国都位于番禺，疆域包括今天中国的广东、' +
+        '广西两省区的大部份地区，福建省、湖南、贵州、云南的一小部份地区和越南的北部。' +
+        '南越国是秦朝灭亡后，由南海郡尉赵佗于前203年起兵兼并桂林郡和象郡后建立。' +
+        '前196年和前179年，南越国曾先后两次名义上臣属于西汉，成为西汉的“外臣”。前112年，' +
+        '南越国末代君主赵建德与西汉发生战争，被汉武帝于前111年所灭。南越国共存在93年，' +
+        '历经五代君主。南越国是岭南地区的第一个有记载的政权国家，采用封建制和郡县制并存的制度，' +
+        '它的建立保证了秦末乱世岭南地区社会秩序的稳定，有效的改善了岭南地区落后的政治、##济现状。\n';
+
+// test that empty file will be created and have content added
+var filename = join(common.fixturesDir, 'append-sync.txt');
+
+common.error('appending to ' + filename);
+fs.appendFileSync(filename, data);
+
+var fileData = fs.readFileSync(filename);
+
+assert.equal(Buffer.byteLength(data), fileData.length);
+
+// test that appends data to a non empty file
+var filename2 = join(common.fixturesDir, 'append-sync2.txt');
+fs.writeFileSync(filename2, currentFileData);
+
+common.error('appending to ' + filename2);
+fs.appendFileSync(filename2, data);
+
+var fileData2 = fs.readFileSync(filename2);
+
+assert.equal(Buffer.byteLength(data) + currentFileData.length, fileData2.length);
+
+// test that appendFileSync accepts buffers
+var filename3 = join(common.fixturesDir, 'append-sync3.txt');
+fs.writeFileSync(filename3, currentFileData);
+
+common.error('appending to ' + filename3);
+
+var buf = new Buffer(data, 'utf8');
+fs.appendFileSync(filename3, buf);
+
+var fileData3 = fs.readFileSync(filename3);
+
+assert.equal(buf.length + currentFileData.length, fileData3.length);
+
+// test that appendFile accepts numbers.
+var filename4 = join(common.fixturesDir, 'append-sync4.txt');
+fs.writeFileSync(filename4, currentFileData);
+
+common.error('appending to ' + filename4);
+fs.appendFileSync(filename4, num);
+
+var fileData4 = fs.readFileSync(filename4);
+
+assert.equal(Buffer.byteLength('' + num) + currentFileData.length, fileData4.length);
+
+//exit logic for cleanup
+
+process.on('exit', function() {
+  common.error('done');
+
+  fs.unlinkSync(filename);
+  fs.unlinkSync(filename2);
+  fs.unlinkSync(filename3);
+  fs.unlinkSync(filename4);
+});

test/simple/test-fs-append-file.js

@@ -0,0 +1,126 @@
+// 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 fs = require('fs');
+var join = require('path').join;
+
+var filename = join(common.fixturesDir, 'append.txt');
+
+common.error('appending to ' + filename);
+
+var currentFileData = 'ABCD';
+
+var n = 220;
+var s = '南越国是前203年至前111年存在于岭南地区的一个国家，国都位于番禺，疆域包括今天中国的广东、' +
+        '广西两省区的大部份地区，福建省、湖南、贵州、云南的一小部份地区和越南的北部。' +
+        '南越国是秦朝灭亡后，由南海郡尉赵佗于前203年起兵兼并桂林郡和象郡后建立。' +
+        '前196年和前179年，南越国曾先后两次名义上臣属于西汉，成为西汉的“外臣”。前112年，' +
+        '南越国末代君主赵建德与西汉发生战争，被汉武帝于前111年所灭。南越国共存在93年，' +
+        '历经五代君主。南越国是岭南地区的第一个有记载的政权国家，采用封建制和郡县制并存的制度，' +
+        '它的建立保证了秦末乱世岭南地区社会秩序的稳定，有效的改善了岭南地区落后的政治、##济现状。\n';
+
+var ncallbacks = 0;
+
+// test that empty file will be created and have content added
+fs.appendFile(filename, s, function(e) {
+  if (e) throw e;
+
+  ncallbacks++;
+  common.error('appended to file');
+
+  fs.readFile(filename, function(e, buffer) {
+    if (e) throw e;
+    common.error('file read');
+    ncallbacks++;
+    assert.equal(Buffer.byteLength(s), buffer.length);
+  });
+});
+
+// test that appends data to a non empty file
+var filename2 = join(common.fixturesDir, 'append2.txt');
+fs.writeFileSync(filename2, currentFileData);
+
+fs.appendFile(filename2, s, function(e) {
+  if (e) throw e;
+
+  ncallbacks++;
+  common.error('appended to file2');
+
+  fs.readFile(filename2, function(e, buffer) {
+    if (e) throw e;
+    common.error('file2 read');
+    ncallbacks++;
+    assert.equal(Buffer.byteLength(s) + currentFileData.length, buffer.length);
+  });
+});
+
+// test that appendFile accepts buffers
+var filename3 = join(common.fixturesDir, 'append3.txt');
+fs.writeFileSync(filename3, currentFileData);
+
+var buf = new Buffer(s, 'utf8');
+common.error('appending to ' + filename3);
+
+fs.appendFile(filename3, buf, function(e) {
+   if (e) throw e;
+
+   ncallbacks++;
+   common.error('appended to file3');
+
+  fs.readFile(filename3, function(e, buffer) {
+    if (e) throw e;
+    common.error('file3 read');
+    ncallbacks++;
+    assert.equal(buf.length + currentFileData.length, buffer.length);
+  });
+});
+
+// test that appendFile accepts numbers.
+var filename4 = join(common.fixturesDir, 'append4.txt');
+fs.writeFileSync(filename4, currentFileData);
+
+common.error('appending to ' + filename4);
+
+fs.appendFile(filename4, n, function(e) {
+  if (e) throw e;
+
+  ncallbacks++;
+  common.error('appended to file4');
+
+  fs.readFile(filename4, function(e, buffer) {
+    if (e) throw e;
+    common.error('file4 read');
+    ncallbacks++;
+    assert.equal(Buffer.byteLength('' + n) + currentFileData.length, buffer.length);
+  });
+});
+
+process.on('exit', function() {
+  common.error('done');
+  assert.equal(8, ncallbacks);
+
+  fs.unlinkSync(filename);
+  fs.unlinkSync(filename2);
+  fs.unlinkSync(filename3);
+  fs.unlinkSync(filename4);
+});