Change to a simpler upgrade scheme for Chrome Frame whereby we register a win...

chrome_frame/chrome_tab.cc

 // Copyright (c) 2009 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.
 
 // chrome_tab.cc : Implementation of DLL Exports.
 
 // Include without path to make GYP build see it.
 #include "chrome_tab.h"  // NOLINT
 
 #include <atlsecurity.h>
@@ skipping 57 matching lines @@
 
 // Object entries go here instead of with each object, so that we can move
 // the objects to a lib. Also reduces magic.
 OBJECT_ENTRY_AUTO(CLSID_ChromeFrameBHO, Bho)
 OBJECT_ENTRY_AUTO(__uuidof(ChromeActiveDocument), ChromeActiveDocument)
 OBJECT_ENTRY_AUTO(__uuidof(ChromeFrame), ChromeFrameActivex)
 OBJECT_ENTRY_AUTO(__uuidof(ChromeProtocol), ChromeProtocol)
 
 
 // See comments in DllGetClassObject.
-DllRedirector g_dll_redirector;
-Lock g_redirector_lock;
+LPFNGETCLASSOBJECT g_dll_get_class_object_redir_ptr = NULL;
 
 class ChromeTabModule
     : public AtlPerUserModule<CAtlDllModuleT<ChromeTabModule> > {
  public:
   typedef AtlPerUserModule<CAtlDllModuleT<ChromeTabModule> > ParentClass;
 
   DECLARE_LIBID(LIBID_ChromeTabLib)
   DECLARE_REGISTRY_APPID_RESOURCEID(IDR_CHROMETAB,
                                     "{FD9B1B31-F4D8-436A-8F4F-D3C2E36733D3}")
 
@@ skipping 76 matching lines @@
     ATL::CTrace::s_trace.ChangeCategory(atlTraceRegistrar, 0,
                                         ATLTRACESTATUS_DISABLED);
 #endif
     InitGoogleUrl();
 
     g_exit_manager = new base::AtExitManager();
     CommandLine::Init(0, NULL);
     InitializeCrashReporting();
     logging::InitLogging(NULL, logging::LOG_ONLY_TO_SYSTEM_DEBUG_LOG,
                         logging::LOCK_LOG_FILE, logging::DELETE_OLD_LOG_FILE);
+
+    if (!DllRedirector::RegisterAsFirstCFModule()) {
+      // We are not the first ones in, get the module who registered first.
+      HMODULE original_module = DllRedirector::GetFirstCFModule();
+      DCHECK(original_module != NULL)
+          << "Could not get first CF module handle.";
+      HMODULE this_module = reinterpret_cast<HMODULE>(&__ImageBase);
+      if (original_module != this_module) {
+        // Someone else was here first, try and get a pointer to their
+        // DllGetClassObject export:
+        g_dll_get_class_object_redir_ptr =
+            DllRedirector::GetDllGetClassObjectPtr(original_module);
+        DCHECK(g_dll_get_class_object_redir_ptr != NULL)
+            << "Found CF module with no DllGetClassObject export.";
+      }
+    }
+
     // Enable ETW logging.
     logging::LogEventProvider::Initialize(kChromeFrameProvider);
   } else if (reason == DLL_PROCESS_DETACH) {
+    DllRedirector::UnregisterAsFirstCFModule();
     g_patch_helper.UnpatchIfNeeded();
     delete g_exit_manager;
     g_exit_manager = NULL;
     ShutdownCrashReporting();
   }
   return _AtlModule.DllMain(reason, reserved);
 }
 
 #ifdef _MANAGED
 #pragma managed(pop)
@@ skipping 126 matching lines @@
   return S_OK;
 }
 
 // Used to determine whether the DLL can be unloaded by OLE
 STDAPI DllCanUnloadNow() {
   return _AtlModule.DllCanUnloadNow();
 }
 
 // Returns a class factory to create an object of the requested type
 STDAPI DllGetClassObject(REFCLSID rclsid, REFIID riid, LPVOID* ppv) {
-  // On first call, we scan the loaded module list to see if an older version
-  // of Chrome Frame is already loaded. If it is, then we delegate all calls
-  // to DllGetClassObject to it. This is to avoid having instances of
-  // different versions of e.g. the BHO through an upgrade. It also prevents
-  // us from repeatedly patching.
-  LPFNGETCLASSOBJECT redir_ptr = NULL;
-  {
-    AutoLock lock(g_redirector_lock);
-    g_dll_redirector.EnsureInitialized(L"npchrome_frame.dll",
-                                       CLSID_ChromeActiveDocument);
-    redir_ptr = g_dll_redirector.get_dll_get_class_object_ptr();
-  }
-
-  if (redir_ptr) {
-    return redir_ptr(rclsid, riid, ppv);
+  // If we found another module present when we were loaded, then delegate to
+  // that:
+  if (g_dll_get_class_object_redir_ptr) {
+    return g_dll_get_class_object_redir_ptr(rclsid, riid, ppv);
   } else {
     if (g_patch_helper.InitializeAndPatchProtocolsIfNeeded()) {
       // We should only get here once.
       UrlMkSetSessionOption(URLMON_OPTION_USERAGENT_REFRESH, NULL, 0, 0);
     }
 
     return _AtlModule.DllGetClassObject(rclsid, riid, ppv);
   }
 }
 
@@ skipping 235 matching lines @@
     sd.GetDacl(&new_dacl);
     new_dacl.AddAllowedAce(token_.GetUser(), GENERIC_WRITE | GENERIC_READ);
     if (AtlSetDacl(object_name.c_str(), SE_REGISTRY_KEY, new_dacl)) {
       result = SetOrDeleteMimeHandlerKey(enable);
     }
   }
 
   backup.RestoreSecurity(object_name.c_str());
   return result;
 }