Emit end event only once

fixes nodejs#2888

Previously a pair of end events would be emitted if a response was
paused/resumed, and the underlying socket was closed while the
response was paused

lib/http.js

@@ -149,7 +149,7 @@ var parsers = new FreeList('parsers', 1000, function() {
         parser.incoming._pendings.push(END_OF_FILE);
       } else {
         parser.incoming.readable = false;
-        parser.incoming.emit('end');
+        parser.incoming._emitEnd();
       }
     }
 
@@ -261,6 +261,8 @@ function IncomingMessage(socket) {
   this._paused = false;
   this._pendings = [];
 
+  this._endEmitted = false;
+
   // request (server) only
   this.url = '';
 
@@ -298,6 +300,12 @@ IncomingMessage.prototype.resume = function() {
   if (this.socket) {
     this.socket.resume();
   }
+
+  this._emitPending();
+};
+
+
+IncomingMessage.prototype._emitPending = function(callback) {
   if (this._pendings.length) {
     var self = this;
     process.nextTick(function() {
@@ -309,10 +317,16 @@ IncomingMessage.prototype.resume = function() {
         } else {
           assert(self._pendings.length === 0);
           self.readable = false;
-          self.emit('end');
+          self._emitEnd();
         }
       }
+
+      if (callback) {
+        callback();
+      }
     });
+  } else if (callback) {
+    callback();
   }
 };
 
@@ -329,6 +343,15 @@ IncomingMessage.prototype._emitData = function(d) {
 };
 
 
+IncomingMessage.prototype._emitEnd = function() {
+  if (!this._endEmitted) {
+    this.emit('end');
+  }
+
+  this._endEmitted = true;
+};
+
+
 // Add the given (field, value) pair to the message
 //
 // Per RFC2616, section 4.2 it is acceptable to join multiple instances of the
@@ -1315,8 +1338,10 @@ ClientRequest.prototype.onSocket = function(socket) {
       if (req.res && req.res.readable) {
         // Socket closed before we emitted 'end' below.
         req.res.emit('aborted');
-        req.res.emit('end');
-        req.res.emit('close');
+        req.res._emitPending(function() {
+          req.res._emitEnd();
+          req.res.emit('close');
+        });
       } else if (!req.res && !req._hadError) {
         // This socket error fired before we started to
         // receive a response. The error needs to

test/simple/test-http-pause-resume-one-end.js

@@ -0,0 +1,58 @@
+// 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 http = require('http');
+
+var server = http.Server(function(req, res) {
+  res.writeHead(200, {'Content-Type': 'text/plain'});
+  res.end('Hello World\n');
+  server.close();
+});
+
+
+var dataCount = 0, endCount = 0;
+
+server.listen(common.PORT, function() {
+  var opts = {
+    port: common.PORT,
+    headers: { connection: 'close' }
+  };
+
+  http.get(opts, function(res) {
+    res.on('data', function(chunk) {
+      dataCount++;
+      res.pause();
+    });
+
+    res.on('end', function() {
+      endCount++;
+      res.resume();
+    });
+  });
+});
+
+
+process.on('exit', function() {
+  assert.equal(1, dataCount);
+  assert.equal(1, endCount);
+});