fs: fix ReadStream / WriteStream double close bug

* Calling fs.ReadStream.destroy() or fs.WriteStream.destroy() twice would close
  the file descriptor twice. That's bad because the file descriptor may have
  been repurposed in the mean time.

* A bad value check in fs.ReadStream.prototype.destroy() would prevent a stream
  created with fs.createReadStream({fd:0}) from getting closed.

lib/fs.js

@@ -1167,6 +1167,8 @@ ReadStream.prototype._emitData = function(d) {
 
 ReadStream.prototype.destroy = function(cb) {
   var self = this;
+
+  if (!this.readable) return;
   this.readable = false;
 
   function close() {
@@ -1182,10 +1184,10 @@ ReadStream.prototype.destroy = function(cb) {
     });
   }
 
-  if (this.fd) {
-    close();
-  } else {
+  if (this.fd === null) {
     this.addListener('open', close);
+  } else {
+    close();
   }
 };
 
@@ -1367,6 +1369,8 @@ WriteStream.prototype.end = function(data, encoding, cb) {
 
 WriteStream.prototype.destroy = function(cb) {
   var self = this;
+
+  if (!this.writable) return;
   this.writable = false;
 
   function close() {
@@ -1382,10 +1386,10 @@ WriteStream.prototype.destroy = function(cb) {
     });
   }
 
-  if (this.fd) {
-    close();
-  } else {
+  if (this.fd === null) {
     this.addListener('open', close);
+  } else {
+    close();
   }
 };
 

test/simple/test-fs-stream-double-close.js

@@ -0,0 +1,61 @@
+// 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');
+
+test1(fs.createReadStream(__filename));
+test2(fs.createReadStream(__filename));
+test3(fs.createReadStream(__filename));
+
+test1(fs.createWriteStream(common.tmpDir + '/dummy1'));
+test2(fs.createWriteStream(common.tmpDir + '/dummy2'));
+test3(fs.createWriteStream(common.tmpDir + '/dummy3'));
+
+function test1(stream) {
+  stream.destroy();
+  stream.destroy();
+}
+
+function test2(stream) {
+  stream.destroy();
+  stream.on('open', function(fd) {
+    stream.destroy();
+    open_cb_called++;
+  });
+  process.on('exit', function() {
+    assert.equal(open_cb_called, 1);
+  });
+  var open_cb_called = 0;
+}
+
+function test3(stream) {
+  stream.on('open', function(fd) {
+    stream.destroy();
+    stream.destroy();
+    open_cb_called++;
+  });
+  process.on('exit', function() {
+    assert.equal(open_cb_called, 1);
+  });
+  var open_cb_called = 0;
+}