chrome_frame/buggy_bho_handling.h

   1 // Copyright (c) 2010 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef CHROME_FRAME_BUGGY_BHO_HANDLING_H_
   6 #define CHROME_FRAME_BUGGY_BHO_HANDLING_H_
   7
   8 #include <atlbase.h>
   9 #include <atlcom.h>
  10 #include <exdisp.h>
  11
  12 #include <vector>
  13
  14 #include "base/threading/thread_local.h"
  15 #include "base/win/scoped_comptr.h"
  16
  17 namespace buggy_bho {
  18
  19 // Method prototype for IDispatch::Invoke.
  20 typedef HRESULT (__stdcall* InvokeFunc)(IDispatch* me, DISPID dispid,
  21                                         REFIID riid, LCID lcid, WORD flags,
  22                                         DISPPARAMS* params, VARIANT* result,
  23                                         EXCEPINFO* ei, UINT* err);
  24
  25 // Construct a per thread instance of this class before firing web browser
  26 // events that can be sent to buggy BHOs.  This class will intercept those
  27 // BHOs (see list in cc file) and ignore notifications to those components
  28 // as long as ChromeFrame is the active view.
  29 class BuggyBhoTls {
  30  public:
  31   // This method traverses the list of DWebBrowserEvents and DWebBrowserEvents2
  32   // subscribers and checks if any of the sinks belong to a list of
  33   // known-to-be-buggy BHOs.
  34   // For each of those, a patch will be applied that temporarily ignores certain
  35   // invokes.
  36   HRESULT PatchBuggyBHOs(IWebBrowser2* browser);
  37
  38   // Returns the instance of the BuggyBhoTls object for the current thread.
  39   static BuggyBhoTls* GetInstance();
  40
  41   // Destroys the BuggyBhoTls instance foe the current thread.
  42   static void DestroyInstance();
  43
  44   void set_web_browser(IWebBrowser2* web_browser2) {
  45     web_browser2_ = web_browser2;
  46   }
  47
  48  protected:
  49   BuggyBhoTls();
  50   ~BuggyBhoTls();
  51   // internal implementation:
  52
  53   // Called when a buggy instance is found to be subscribing to browser events.
  54   void AddBuggyObject(IDispatch* obj);
  55
  56   // Called from our patch to check if calls for this object should be ignored.
  57   // The reason we do this check is because there might be more than one browser
  58   // object running on the same thread (e.g. IE6) with one running CF and the
  59   // other MSHTML.  We don't want to drop events being fired by MSHTML, only
  60   // events fired by CF since these BHOs should handle MSHTML correctly.
  61   bool ShouldSkipInvoke(IDispatch* obj) const;
  62
  63   // Static, protected member methods
  64
  65   // Patches a subscriber if it belongs to a buggy dll.
  66   bool PatchIfBuggy(IUnknown* unk, const IID& diid);
  67
  68   // Patches the IDispatch::Invoke method.
  69   static HRESULT PatchInvokeMethod(PROC* invoke);
  70
  71   // This is our substitute function that is called instead of the buggy DLLs.
  72   // Here we call IsBuggyObject to check if we should ignore invokes or allow
  73   // them to go through.
  74   static STDMETHODIMP BuggyBhoInvoke(InvokeFunc original, IDispatch* me,
  75       DISPID dispid, REFIID riid, LCID lcid, WORD flags, DISPPARAMS* params,
  76       VARIANT* result, EXCEPINFO* ei, UINT* err);
  77
  78  protected:
  79   // List of buggy subscribers.
  80   std::vector<IDispatch*> bad_objects_;
  81   // Where we store the current thread's instance.
  82   static base::ThreadLocalPointer<BuggyBhoTls> s_bad_object_tls_;
  83   // The IWebBrowser2 instance for this thread.
  84   base::win::ScopedComPtr<IWebBrowser2> web_browser2_;
  85   // Set to true when we are done patching the event sinks of buggy bho's.
  86   bool patched_;
  87 };
  88
  89 }  // end namespace buggy_bho
  90
  91 #endif  // CHROME_FRAME_BUGGY_BHO_HANDLING_H_