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.


Review URL: http://codereview.chromium.org/1562018

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@44473 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 80 insertions, 0 deletions

diff --git a/chrome_frame/module_utils.h b/chrome_frame/module_utils.h
new file mode 100644
index 0000000..e5d8a68
--- /dev/null
+++ b/chrome_frame/module_utils.h
@@ -0,0 +1,80 @@
+// Copyright (c) 2010 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.
+
+#ifndef CHROME_FRAME_MODULE_UTILS_H_
+#define CHROME_FRAME_MODULE_UTILS_H_
+
+#include <ObjBase.h>
+#include <windows.h>
+
+#include <map>
+
+// A helper class that will find the named loaded module in the current
+// process with the lowest version, increment its ref count and return
+// a pointer to its DllGetClassObject() function if it exports one. If
+// the oldest named module is the current module, then this class does nothing
+// (does not muck with module ref count) and calls to
+// get_dll_get_class_object_ptr() will return NULL.
+class DllRedirector {
+ public:
+  typedef std::map<std::wstring, HMODULE> PathToHModuleMap;
+
+  DllRedirector();
+  ~DllRedirector();
+
+  // Must call this before calling get_dll_get_class_object_ptr(). On first call
+  // this performs the work of scanning the loaded modules for an old version
+  // to delegate to. Not thread safe.
+  void EnsureInitialized(const wchar_t* module_name, REFCLSID clsid);
+
+  LPFNGETCLASSOBJECT get_dll_get_class_object_ptr() const;
+
+ private:
+
+  // Returns the pointer to the named loaded module's DllGetClassObject export
+  // or NULL if either the pointer could not be found or if the pointer would
+  // point into the current module.
+  // Sets module_handle_ and increments the modules reference count.
+  //
+  // For sanity's sake, the module must return a non-null class factory for
+  // the given class id.
+  LPFNGETCLASSOBJECT GetDllGetClassObjectFromModuleName(
+      const wchar_t* module_name, REFCLSID clsid);
+
+  // Returns a handle in |module_handle| to the loaded module called
+  // |module_name| in the current process. If there are multiple modules with
+  // the same name, it returns the module with the oldest version number in its
+  // VERSIONINFO block. The version string is expected to be of a form that
+  // base::Version can parse.
+  //
+  // For sanity's sake, when there are multiple instances of the module,
+  // |product_short_name|, if non-NULL, must match the module's
+  // ProductShortName value
+  //
+  // Returns true if a named module with the given ProductShortName can be
+  // found, returns false otherwise. Can return the current module handle.
+  bool GetOldestNamedModuleHandle(const std::wstring& module_name,
+                                  REFCLSID clsid,
+                                  HMODULE* module_handle);
+
+  // Given a PathToBaseAddressMap, iterates over the module images whose paths
+  // are the keys and returns the handle to the module with the lowest
+  // version number in its VERSIONINFO block whose DllGetClassObject returns a
+  // class factory for the given CLSID.
+  HMODULE GetHandleOfOldestModule(const PathToHModuleMap& map, REFCLSID clsid);
+
+ private:
+  // Helper function to return the DllGetClassObject function pointer from
+  // the given module. On success, the return value is non-null and module
+  // will have had its reference count incremented.
+  LPFNGETCLASSOBJECT GetDllGetClassObjectPtr(HMODULE module);
+
+  HMODULE module_handle_;
+  LPFNGETCLASSOBJECT dcgo_ptr_;
+  bool initialized_;
+
+  friend class ModuleUtilsTest;
+};
+
+#endif  // CHROME_FRAME_MODULE_UTILS_H_