Add a helper process to Chrome Frame to allow for non-administrative installs...

chrome_frame/bho_loader.cc

+// 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.
+
+#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";
+
+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")) {
+    // Step 2: Check to see if the window is of the right class.
+    // 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.
+    if (IsWindowOfClass(window, kStatusBarWindowClass)) {
+      HWND parent_window = GetParent(window);
+      // Step 3:
+      // Parent window of status bar window is the web browser window. Try to
+      // get its IWebBrowser2 interface
+      CComPtr<IWebBrowser2> browser;
+      UtilGetWebBrowserObjectFromWindow(parent_window, __uuidof(browser),
+                                        reinterpret_cast<void**>(&browser));
+      if (browser) {
+        // TODO(robertshield): We may need to find a way to prevent doing this
+        // twice. A marker of some kind would do. Ask during review for good
+        // suggestions.
+
+        // Step 4:
+        // We have the IWebBrowser2 interface. Now create the BHO instance
+        CComPtr<IObjectWithSite> bho_object;
+        HRESULT error_code =  bho_object.CoCreateInstance(CLSID_ChromeFrameBHO,
+                                                          NULL,
+                                                          CLSCTX_INPROC_SERVER);
+
+        if (SUCCEEDED(error_code) && bho_object) {
+          // Step 5:
+          // Initialize the BHO by calling SetSite and passing it IWebBrowser2
+          error_code = bho_object->SetSite(browser);
+          if (SUCCEEDED(error_code)) {
+            // 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.
+            wchar_t bho_clsid_as_string[MAX_PATH] = {0};
+            StringFromGUID2(CLSID_ChromeFrameBHO, bho_clsid_as_string,
+                            ARRAYSIZE(bho_clsid_as_string));
+
+            CComBSTR bho_clsid_as_string_bstr(bho_clsid_as_string);
+            CComVariant object_variant(bho_object);
+
+            browser->PutProperty(bho_clsid_as_string_bstr, object_variant);
+          }
+        }
+      }
+    }
+  }
+}
+
+bool BHOLoader::StartHook() {
+  return hooker_->StartHook();
+}
+
+void BHOLoader::StopHook() {
+  hooker_->StopHook();
+}
+
+BHOLoader* BHOLoader::GetInstance() {
+  static BHOLoader loader;
+  return &loader;
+}