Allow multiple exits from LaunchUpdateCommand() for safety and clarity.

chrome_frame/update_launcher.cc

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "chrome_frame/update_launcher.h"
 
 #include <windows.h>
 #include <Shellapi.h>
 
 #include "base/win/scoped_com_initializer.h"
@@ skipping 32 matching lines @@
     if (args) {
       if (num_args == 3 && _wcsicmp(args[1], kUpdateCommandFlag) == 0)
         command = args[2];
       ::LocalFree(args);
     }
   }
 
   return command;
 }
 
-// Because we do not have 'base' and all of its pretty RAII helpers, please
-// ensure that this function only ever contains a single 'return', in order
-// to reduce the chance of introducing a leak.
 DWORD LaunchUpdateCommand(const std::wstring& command) {
-  DWORD exit_code = kLaunchFailureExitCode;
+  base::win::ScopedCOMInitializer com_initializer;
+  if (!com_initializer.succeeded())
+    return kLaunchFailureExitCode;
 
-  base::win::ScopedCOMInitializer com_initializer;
-  if (com_initializer.succeeded()) {
-    base::win::ScopedComPtr<IProcessLauncher> ipl;
-    HANDLE process = NULL;
+  base::win::ScopedComPtr<IProcessLauncher> ipl;
+  if (FAILED(ipl.CreateInstance(__uuidof(ProcessLauncherClass))))
+    return kLaunchFailureExitCode;
 
-    HRESULT hr = ipl.CreateInstance(__uuidof(ProcessLauncherClass));
+  ULONG_PTR phandle = NULL;

[grt (UTC plus 2), 2013/04/15 23:32:54]

can this be a base::win::ScopedHandle, using its Receive() method on line 64? if
not, how about making |process| on line 67 a ScopedHandle?

[Peter Kasting, 2013/04/16 00:09:22]

I don't think using Receive() will work because the callee expects a ULONG_PTR*.
 But I converted |process| to be a ScopedHandle.

+  if (FAILED(ipl->LaunchCmdElevated(kChromeFrameGuid, command.c_str(),
+                                    ::GetCurrentProcessId(), &phandle)))
+    return kLaunchFailureExitCode;
 
-    if (SUCCEEDED(hr)) {
-      ULONG_PTR phandle = NULL;
-      DWORD id = ::GetCurrentProcessId();
-
-      hr = ipl->LaunchCmdElevated(kChromeFrameGuid,
-                                  command.c_str(), id, &phandle);
-      if (SUCCEEDED(hr)) {
-        process = reinterpret_cast<HANDLE>(phandle);
-        exit_code = WaitForProcessExitCode(process);
-      }
-    }
-
-    if (process)
-      ::CloseHandle(process);
-  }
-
+  HANDLE process = reinterpret_cast<HANDLE>(phandle);
+  DWORD exit_code = WaitForProcessExitCode(process);
+  if (process)
+    ::CloseHandle(process);
   return exit_code;
 }
 
 }  // namespace process_launcher