widget/windows/WindowHook.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
   2  *
   3  * This Source Code Form is subject to the terms of the Mozilla Public
   4  * License, v. 2.0. If a copy of the MPL was not distributed with this
   5  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
   6
   7 #include "WindowHook.h"
   8 #include "nsWindow.h"
   9 #include "nsWindowDefs.h"
  10
  11 namespace mozilla {
  12 namespace widget {
  13
  14 nsresult WindowHook::AddHook(UINT nMsg, Callback callback, void* context) {
  15   MessageData* data = LookupOrCreate(nMsg);
  16
  17   if (!data) return NS_ERROR_OUT_OF_MEMORY;
  18
  19   // Ensure we don't overwrite another hook
  20   NS_ENSURE_TRUE(nullptr == data->hook.cb, NS_ERROR_UNEXPECTED);
  21
  22   data->hook = CallbackData(callback, context);
  23
  24   return NS_OK;
  25 }
  26
  27 nsresult WindowHook::RemoveHook(UINT nMsg, Callback callback, void* context) {
  28   CallbackData cbdata(callback, context);
  29   MessageData* data = Lookup(nMsg);
  30   if (!data) return NS_ERROR_UNEXPECTED;
  31   if (data->hook != cbdata) return NS_ERROR_UNEXPECTED;
  32   data->hook = CallbackData();
  33
  34   DeleteIfEmpty(data);
  35   return NS_OK;
  36 }
  37
  38 nsresult WindowHook::AddMonitor(UINT nMsg, Callback callback, void* context) {
  39   MessageData* data = LookupOrCreate(nMsg);
  40   return (data && data->monitors.AppendElement(CallbackData(callback, context),
  41                                                fallible))
  42              ? NS_OK
  43              : NS_ERROR_OUT_OF_MEMORY;
  44 }
  45
  46 nsresult WindowHook::RemoveMonitor(UINT nMsg, Callback callback,
  47                                    void* context) {
  48   CallbackData cbdata(callback, context);
  49   MessageData* data = Lookup(nMsg);
  50   if (!data) return NS_ERROR_UNEXPECTED;
  51   CallbackDataArray::index_type idx = data->monitors.IndexOf(cbdata);
  52   if (idx == CallbackDataArray::NoIndex) return NS_ERROR_UNEXPECTED;
  53   data->monitors.RemoveElementAt(idx);
  54   DeleteIfEmpty(data);
  55   return NS_OK;
  56 }
  57
  58 WindowHook::MessageData* WindowHook::Lookup(UINT nMsg) {
  59   MessageDataArray::index_type idx;
  60   for (idx = 0; idx < mMessageData.Length(); idx++) {
  61     MessageData& data = mMessageData[idx];
  62     if (data.nMsg == nMsg) return &data;
  63   }
  64   return nullptr;
  65 }
  66
  67 WindowHook::MessageData* WindowHook::LookupOrCreate(UINT nMsg) {
  68   MessageData* data = Lookup(nMsg);
  69   if (!data) {
  70     data = mMessageData.AppendElement();
  71
  72     if (!data) return nullptr;
  73
  74     data->nMsg = nMsg;
  75   }
  76   return data;
  77 }
  78
  79 void WindowHook::DeleteIfEmpty(MessageData* data) {
  80   // Never remove a MessageData that has still a hook or monitor entries.
  81   if (data->hook || !data->monitors.IsEmpty()) return;
  82
  83   MessageDataArray::index_type idx;
  84   idx = data - mMessageData.Elements();
  85   NS_ASSERTION(
  86       idx < mMessageData.Length(),
  87       "Attempted to delete MessageData that doesn't belong to this array!");
  88   mMessageData.RemoveElementAt(idx);
  89 }
  90
  91 bool WindowHook::Notify(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam,
  92                         MSGResult& aResult) {
  93   MessageData* data = Lookup(nMsg);
  94   if (!data) return false;
  95
  96   uint32_t length = data->monitors.Length();
  97   for (uint32_t midx = 0; midx < length; midx++) {
  98     data->monitors[midx].Invoke(hWnd, nMsg, wParam, lParam, &aResult.mResult);
  99   }
 100
 101   aResult.mConsumed =
 102       data->hook.Invoke(hWnd, nMsg, wParam, lParam, &aResult.mResult);
 103   return aResult.mConsumed;
 104 }
 105
 106 bool WindowHook::CallbackData::Invoke(HWND hWnd, UINT msg, WPARAM wParam,
 107                                       LPARAM lParam, LRESULT* aResult) {
 108   if (!cb) return false;
 109   return cb(context, hWnd, msg, wParam, lParam, aResult);
 110 }
 111
 112 }  // namespace widget
 113 }  // namespace mozilla