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// 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_BUGGY_BHO_HANDLING_H_
#define CHROME_FRAME_BUGGY_BHO_HANDLING_H_
#include <atlbase.h>
#include <atlcom.h>
#include <exdisp.h>
#include <vector>
#include "base/thread_local.h"
namespace buggy_bho {
// Method prototype for IDispatch::Invoke.
typedef HRESULT (__stdcall* InvokeFunc)(IDispatch* me, DISPID dispid,
REFIID riid, LCID lcid, WORD flags,
DISPPARAMS* params, VARIANT* result,
EXCEPINFO* ei, UINT* err);
// Construct an instance of this class on the stack when firing web browser
// events that can be sent to buggy BHOs. This class will intercept those
// BHOs (see list in cc file) and ignore notifications to those components
// for as long as the BuggyBhoTls instance on the stack lives.
class BuggyBhoTls {
public:
BuggyBhoTls();
~BuggyBhoTls();
// Call after instantiating an instance of BuggyBhoTls. This method traverses
// the list of DWebBrowserEvents and DWebBrowserEvents2 subscribers and checks
// if any of the sinks belong to a list of known-to-be-buggy BHOs.
// For each of those, a patch will be applied that temporarily ignores certain
// invokes.
static HRESULT PatchBuggyBHOs(IWebBrowser2* browser);
protected:
// internal implementation:
// Called when a buggy instance is found to be subscribing to browser events.
void AddBuggyObject(IDispatch* obj);
// Called from our patch to check if calls for this object should be ignored.
// The reason we do this check is because there might be more than one browser
// object running on the same thread (e.g. IE6) with one running CF and the
// other MSHTML. We don't want to drop events being fired by MSHTML, only
// events fired by CF since these BHOs should handle MSHTML correctly.
bool IsBuggyObject(IDispatch* obj) const;
// Static, protected member methods
// Returns the currently registered (TLS) BuggyBhoTls instance or NULL.
static BuggyBhoTls* FromCurrentThread();
// Patches a subscriber if it belongs to a buggy dll.
static bool PatchIfBuggy(CONNECTDATA* cd, const IID& diid);
// Patches the IDispatch::Invoke method.
static HRESULT PatchInvokeMethod(PROC* invoke);
// This is our substitute function that is called instead of the buggy DLLs.
// Here we call IsBuggyObject to check if we should ignore invokes or allow
// them to go through.
static STDMETHODIMP BuggyBhoInvoke(InvokeFunc original, IDispatch* me,
DISPID dispid, REFIID riid, LCID lcid, WORD flags, DISPPARAMS* params,
VARIANT* result, EXCEPINFO* ei, UINT* err);
protected:
// List of buggy subscribers.
std::vector<IDispatch*> bad_objects_;
// Pointer to a previous instance of BuggyBhoTls on this thread if any.
// Under regular circumstances, this will be NULL. However, there's a chance
// that we could get reentrant calls, hence we maintain a stack.
BuggyBhoTls* previous_instance_;
// Where we store the current thread's instance.
static base::ThreadLocalPointer<BuggyBhoTls> s_bad_object_tls_;
};
} // end namespace buggy_bho
#endif // CHROME_FRAME_BUGGY_BHO_HANDLING_H_
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