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
  15 WindowHook::AddHook(UINT nMsg, Callback callback, void *context) {
  16   MessageData *data = LookupOrCreate(nMsg);
  17
  18   if (!data)
  19     return NS_ERROR_OUT_OF_MEMORY;
  20
  21   // Ensure we don't overwrite another hook
  22   NS_ENSURE_TRUE(nullptr == data->hook.cb, NS_ERROR_UNEXPECTED);
  23
  24   data->hook = CallbackData(callback, context);
  25
  26   return NS_OK;
  27 }
  28
  29 nsresult
  30 WindowHook::RemoveHook(UINT nMsg, Callback callback, void *context) {
  31   CallbackData cbdata(callback, context);
  32   MessageData *data = Lookup(nMsg);
  33   if (!data)
  34     return NS_ERROR_UNEXPECTED;
  35   if (data->hook != cbdata)
  36     return NS_ERROR_UNEXPECTED;
  37   data->hook = CallbackData();
  38
  39   DeleteIfEmpty(data);
  40   return NS_OK;
  41 }
  42
  43 nsresult
  44 WindowHook::AddMonitor(UINT nMsg, Callback callback, void *context) {
  45   MessageData *data = LookupOrCreate(nMsg);
  46   return (data && data->monitors.AppendElement(CallbackData(callback, context)))
  47          ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
  48 }
  49
  50 nsresult
  51 WindowHook::RemoveMonitor(UINT nMsg, Callback callback, void *context) {
  52   CallbackData cbdata(callback, context);
  53   MessageData *data = Lookup(nMsg);
  54   if (!data)
  55     return NS_ERROR_UNEXPECTED;
  56   CallbackDataArray::index_type idx = data->monitors.IndexOf(cbdata);
  57   if (idx == CallbackDataArray::NoIndex)
  58     return NS_ERROR_UNEXPECTED;
  59   data->monitors.RemoveElementAt(idx);
  60   DeleteIfEmpty(data);
  61   return NS_OK;
  62 }
  63
  64 WindowHook::MessageData *
  65 WindowHook::Lookup(UINT nMsg) {
  66   MessageDataArray::index_type idx;
  67   for (idx = 0; idx < mMessageData.Length(); idx++) {
  68     MessageData &data = mMessageData[idx];
  69     if (data.nMsg == nMsg)
  70       return &data;
  71   }
  72   return nullptr;
  73 }
  74
  75 WindowHook::MessageData *
  76 WindowHook::LookupOrCreate(UINT nMsg) {
  77   MessageData *data = Lookup(nMsg);
  78   if (!data) {
  79     data = mMessageData.AppendElement();
  80
  81     if (!data)
  82       return nullptr;
  83
  84     data->nMsg = nMsg;
  85   }
  86   return data;
  87 }
  88
  89 void
  90 WindowHook::DeleteIfEmpty(MessageData *data) {
  91   // Never remove a MessageData that has still a hook or monitor entries.
  92   if (data->hook || !data->monitors.IsEmpty())
  93     return;
  94
  95   MessageDataArray::index_type idx;
  96   idx = data - mMessageData.Elements();
  97   NS_ASSERTION(idx >= 0 && idx < mMessageData.Length(), "Attempted to delete MessageData that doesn't belong to this array!");
  98   mMessageData.RemoveElementAt(idx);
  99 }
 100
 101 bool
 102 WindowHook::Notify(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam,
 103                    MSGResult& aResult)
 104 {
 105   MessageData *data = Lookup(nMsg);
 106   if (!data)
 107     return false;
 108
 109   uint32_t length = data->monitors.Length();
 110   for (uint32_t midx = 0; midx < length; midx++) {
 111     data->monitors[midx].Invoke(hWnd, nMsg, wParam, lParam, &aResult.mResult);
 112   }
 113
 114   aResult.mConsumed =
 115     data->hook.Invoke(hWnd, nMsg, wParam, lParam, &aResult.mResult);
 116   return aResult.mConsumed;
 117 }
 118
 119 bool
 120 WindowHook::CallbackData::Invoke(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam,
 121                                  LRESULT *aResult) {
 122   if (!cb)
 123     return false;
 124   return cb(context, hWnd, msg, wParam, lParam, aResult);
 125 }
 126 } // namespace widget
 127 } // namespace mozilla
 128