blob: 255bb6c0f455b72ba72cae2456c7a39b9dd87e7e [file] [log] [blame]
// Copyright (c) 2011 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.
#include "chrome_frame/bho_loader.h"
#include <atlbase.h>
#include <atlcomcli.h>
#include <exdisp.h>
#include "chrome_frame/chrome_frame_helper_util.h"
#include "chrome_frame/event_hooker.h"
#include "chrome_tab.h" // NOLINT
// Describes the window class we look for.
const wchar_t kStatusBarWindowClass[] = L"msctls_statusbar32";
// On IE9, the status bar is disabled by default, so we look for an
// AsyncBoundaryLayer window instead.
const wchar_t kAsyncBoundaryDnWindow[] = L"asynclayerboundarydn\0";
BHOLoader::BHOLoader() : hooker_(new EventHooker()) {
BHOLoader::~BHOLoader() {
if (hooker_) {
delete hooker_;
hooker_ = NULL;
void BHOLoader::OnHookEvent(DWORD event, HWND window) {
// Step 1: Make sure that we are in a process named iexplore.exe.
if (IsNamedProcess(L"iexplore.exe")) {
if (!IsWindowOfClass(window, kStatusBarWindowClass) &&
!IsWindowOfClass(window, kAsyncBoundaryDnWindow)) {
} else {
// We have the right sort of window, check to make sure it was created
// on the current thread.
DWORD thread_id = GetWindowThreadProcessId(window, NULL);
_ASSERTE(thread_id == GetCurrentThreadId());
// Step 2: Check to see if the window is of the right class.
HWND browser_hwnd = NULL;
if (IsWindowOfClass(window, kStatusBarWindowClass)) {
// For IE8 and under, IE loads BHOs in the WM_CREATE handler of the tab
// window approximately after it creates the status bar window. To be as
// close to IE as possible in our simulation on BHO loading, we watch for
// the status bar to be created and do our simulated BHO loading at that
// time.
browser_hwnd = GetParent(window);
} else if (IsWindowOfClass(window, kAsyncBoundaryDnWindow)) {
// For IE9, the status bar is disabled by default, so we look for an
// AsyncBoundaryWindow to be created. When we find that, look for a
// child window owned by the current thread named "tabwindowclass".
// That will be our browser window.
browser_hwnd = RecurseFindWindow(NULL, L"tabwindowclass", NULL,
_ASSERTE(NULL != browser_hwnd);
if (browser_hwnd != NULL) {
// Step 3:
// Parent window of status bar window is the web browser window. Try to
// get its IWebBrowser2 interface
CComPtr<IWebBrowser2> browser;
UtilGetWebBrowserObjectFromWindow(browser_hwnd, __uuidof(browser),
if (browser) {
if (IsSystemLevelChromeFrameInstalled()) {
// We're in the right place, but a system-level installation has
// appeared. We should leave now.
// Figure out if we're already in the property map.
wchar_t bho_clsid_as_string[MAX_PATH] = {0};
StringFromGUID2(CLSID_ChromeFrameBHO, bho_clsid_as_string,
CComBSTR bho_clsid_as_string_bstr(bho_clsid_as_string);
CComVariant existing_bho;
HRESULT hr = browser->GetProperty(bho_clsid_as_string_bstr,
if (V_VT(&existing_bho) != VT_DISPATCH &&
V_VT(&existing_bho) != VT_UNKNOWN) {
// Step 4:
// We have the IWebBrowser2 interface. Now create the BHO instance
CComPtr<IObjectWithSite> bho_object;
hr = bho_object.CoCreateInstance(CLSID_ChromeFrameBHO,
if (SUCCEEDED(hr) && bho_object) {
// Step 5:
// Initialize the BHO by calling SetSite and passing it IWebBrowser2
hr = bho_object->SetSite(browser);
if (SUCCEEDED(hr)) {
// Step 6:
// Now add the BHO to the collection of automation objects. This
// will ensure that BHO will be accessible from the web pages as
// any other BHO. Importantly, it will make sure that our BHO
// will be cleaned up at the right time along with other BHOs.
CComVariant object_variant(bho_object);
browser->PutProperty(bho_clsid_as_string_bstr, object_variant);
bool BHOLoader::StartHook() {
return hooker_->StartHook();
void BHOLoader::StopHook() {
BHOLoader* BHOLoader::GetInstance() {
static BHOLoader loader;
return &loader;