Recommit of the ill-fated r44474, this time with new compiling goodness.

Add multi-version delegation to Chrome Frame such that CF will scan for older versions on load and delegate to them. This is to support clean upgrade scenarios whereby a new version is registered while IE is running.

BUG=40117
TEST=Register a new CF version while an old one is loaded in IE. Open a few new tabs and observe nothing bad happening.

TBR=tommi
Review URL: http://codereview.chromium.org/1585037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@44522 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 28 insertions, 5 deletions

diff --git a/chrome_frame/chrome_tab.cc b/chrome_frame/chrome_tab.cc
index d8deec4..08e8a84 100644
--- a/chrome_frame/chrome_tab.cc
+++ b/chrome_frame/chrome_tab.cc
@@ -13,6 +13,7 @@
 #include "base/command_line.h"
 #include "base/file_util.h"
 #include "base/file_version_info.h"
+#include "base/lock.h"
 #include "base/logging.h"
 #include "base/logging_win.h"
 #include "base/path_service.h"
@@ -30,6 +31,7 @@
 #include "chrome_frame/chrome_frame_reporting.h"
 #include "chrome_frame/chrome_launcher.h"
 #include "chrome_frame/chrome_protocol.h"
+#include "chrome_frame/module_utils.h"
 #include "chrome_frame/resource.h"
 #include "chrome_frame/utils.h"
 #include "googleurl/src/url_util.h"
@@ -45,7 +47,6 @@ void InitGoogleUrl() {
   url_util::IsStandard(kDummyUrl,
                        url_parse::MakeRange(0, arraysize(kDummyUrl)));
 }
-
 }
 
 static const wchar_t kBhoRegistryPath[] =
@@ -72,6 +73,11 @@ 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;
+
 class ChromeTabModule
     : public AtlPerUserModule<CAtlDllModuleT<ChromeTabModule> > {
  public:
@@ -316,12 +322,29 @@ STDAPI DllCanUnloadNow() {
 
 // Returns a class factory to create an object of the requested type
 STDAPI DllGetClassObject(REFCLSID rclsid, REFIID riid, LPVOID* ppv) {
-  if (g_patch_helper.InitializeAndPatchProtocolsIfNeeded()) {
-    // We should only get here once.
-    UrlMkSetSessionOption(URLMON_OPTION_USERAGENT_REFRESH, NULL, 0, 0);
+  // 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();
   }
 
-  return _AtlModule.DllGetClassObject(rclsid, riid, ppv);
+  if (redir_ptr) {
+    return 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);
+  }
 }
 
 // DllRegisterServer - Adds entries to the system registry