fs: fix naming of truncate/ftruncate functions

For backwards compatibility, fs.truncate(<number>) will proxy to
fs.ftruncate.

Fix #3805

Author: isaacs

doc/api/fs.markdown

@@ -71,15 +71,24 @@ to the completion callback.
 
 Synchronous rename(2).
 
-## fs.truncate(fd, len, [callback])
+## fs.ftruncate(fd, len, [callback])
 
 Asynchronous ftruncate(2). No arguments other than a possible exception are
 given to the completion callback.
 
-## fs.truncateSync(fd, len)
+## fs.ftruncateSync(fd, len)
 
 Synchronous ftruncate(2).
 
+## fs.truncate(path, len, [callback])
+
+Asynchronous truncate(2). No arguments other than a possible exception are
+given to the completion callback.
+
+## fs.truncateSync(path, len)
+
+Synchronous truncate(2).
+
 ## fs.chown(path, uid, gid, [callback])
 
 Asynchronous chown(2). No arguments other than a possible exception are given

lib/fs.js

@@ -440,12 +440,60 @@ fs.renameSync = function(oldPath, newPath) {
                         pathModule._makeLong(newPath));
 };
 
-fs.truncate = function(fd, len, callback) {
-  binding.truncate(fd, len, makeCallback(callback));
+fs.truncate = function(path, len, callback) {
+  if (typeof path === 'number') {
+    // legacy
+    return fs.ftruncate(path, len, callback);
+  }
+  if (typeof len === 'function') {
+    callback = len;
+    len = 0;
+  } else if (typeof len === 'undefined') {
+    len = 0;
+  }
+  fs.open(path, 'w', function(er, fd) {
+    if (er) return callback(er);
+    binding.ftruncate(fd, len, function(er) {
+      fs.close(fd, function(er2) {
+        callback(er || er2);
+      });
+    });
+  });
 };
 
-fs.truncateSync = function(fd, len) {
-  return binding.truncate(fd, len);
+fs.truncateSync = function(path, len) {
+  if (typeof path === 'number') {
+    // legacy
+    return fs.ftruncateSync(path, len, callback);
+  }
+  if (typeof len === 'undefined') {
+    len = 0;
+  }
+  // allow error to be thrown, but still close fd.
+  var fd = fs.openSync(path, 'w');
+  try {
+    var ret = fs.ftruncateSync(fd, len);
+  } finally {
+    fs.closeSync(fd);
+  }
+  return ret;
+};
+
+fs.ftruncate = function(fd, len, callback) {
+  if (typeof len === 'function') {
+    callback = len;
+    len = 0;
+  } else if (typeof len === 'undefined') {
+    len = 0;
+  }
+  binding.ftruncate(fd, len, makeCallback(callback));
+};
+
+fs.ftruncateSync = function(fd, len) {
+  if (typeof len === 'undefined') {
+    len = 0;
+  }
+  return binding.ftruncate(fd, len);
 };
 
 fs.rmdir = function(path, callback) {

src/node_file.cc

@@ -486,7 +486,7 @@ static Handle<Value> Rename(const Arguments& args) {
   }
 }
 
-static Handle<Value> Truncate(const Arguments& args) {
+static Handle<Value> FTruncate(const Arguments& args) {
   HandleScope scope;
 
   if (args.Length() < 2 || !args[0]->IsInt32()) {
@@ -941,7 +941,7 @@ void File::Initialize(Handle<Object> target) {
   NODE_SET_METHOD(target, "fdatasync", Fdatasync);
   NODE_SET_METHOD(target, "fsync", Fsync);
   NODE_SET_METHOD(target, "rename", Rename);
-  NODE_SET_METHOD(target, "truncate", Truncate);
+  NODE_SET_METHOD(target, "ftruncate", FTruncate);
   NODE_SET_METHOD(target, "rmdir", RMDir);
   NODE_SET_METHOD(target, "mkdir", MKDir);
   NODE_SET_METHOD(target, "sendfile", SendFile);

test/fixtures/create-file.js

@@ -24,6 +24,4 @@ var fs = require('fs');
 var file_name = process.argv[2];
 var file_size = parseInt(process.argv[3]);
 
-var fd = fs.openSync(file_name, 'w');
-fs.truncateSync(fd, file_size);
-fs.closeSync(fd);
+fs.truncateSync(file_name, file_size);

test/simple/test-fs-truncate.js

@@ -0,0 +1,135 @@
+// 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');
+var fs = require('fs');
+var tmp = common.tmpDir;
+var filename = path.resolve(tmp, 'truncate-file.txt');
+var data = new Buffer(1024 * 16);
+data.fill('x');
+
+var stat;
+
+// truncateSync
+fs.writeFileSync(filename, data);
+stat = fs.statSync(filename);
+assert.equal(stat.size, 1024 * 16);
+
+fs.truncateSync(filename, 1024);
+stat = fs.statSync(filename);
+assert.equal(stat.size, 1024);
+
+fs.truncateSync(filename);
+stat = fs.statSync(filename);
+assert.equal(stat.size, 0);
+
+// ftruncateSync
+fs.writeFileSync(filename, data);
+var fd = fs.openSync(filename, 'a');
+
+stat = fs.statSync(filename);
+assert.equal(stat.size, 1024 * 16);
+
+fs.ftruncateSync(fd, 1024);
+stat = fs.statSync(filename);
+assert.equal(stat.size, 1024);
+
+fs.ftruncateSync(fd);
+stat = fs.statSync(filename);
+assert.equal(stat.size, 0);
+
+fs.closeSync(fd);
+
+// async tests
+var success = 0;
+testTruncate(function(er) {
+  if (er) throw er;
+  success++;
+  testFtruncate(function(er) {
+    if (er) throw er;
+    success++;
+  });
+});
+
+process.on('exit', function() {
+  assert.equal(success, 2);
+  console.log('ok');
+});
+
+function testTruncate(cb) {
+  fs.writeFile(filename, data, function(er) {
+    if (er) return cb(er);
+    fs.stat(filename, function(er, stat) {
+      if (er) return cb(er);
+      assert.equal(stat.size, 1024 * 16);
+
+      fs.truncate(filename, 1024, function(er) {
+        if (er) return cb(er);
+        fs.stat(filename, function(er, stat) {
+          if (er) return cb(er);
+          assert.equal(stat.size, 1024);
+
+          fs.truncate(filename, function(er) {
+            if (er) return cb(er);
+            fs.stat(filename, function(er, stat) {
+              if (er) return cb(er);
+              assert.equal(stat.size, 0);
+              cb();
+            });
+          });
+        });
+      });
+    });
+  });
+}
+
+
+function testFtruncate(cb) {
+  fs.writeFile(filename, data, function(er) {
+    if (er) return cb(er);
+    fs.stat(filename, function(er, stat) {
+      if (er) return cb(er);
+      assert.equal(stat.size, 1024 * 16);
+
+      fs.open(filename, 'w', function(er, fd) {
+        if (er) return cb(er);
+        fs.ftruncate(fd, 1024, function(er) {
+          if (er) return cb(er);
+          fs.stat(filename, function(er, stat) {
+            if (er) return cb(er);
+            assert.equal(stat.size, 1024);
+
+            fs.ftruncate(fd, function(er) {
+              if (er) return cb(er);
+              fs.stat(filename, function(er, stat) {
+                if (er) return cb(er);
+                assert.equal(stat.size, 0);
+                fs.close(fd, cb);
+              });
+            });
+          });
+        });
+      });
+    });
+  });
+}