widget/src/windows/WindowHook.cpp

   1 /* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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  16  * The Original Code is mozilla.org code.
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  20  * Portions created by the Initial Developer are Copyright (C) 2009
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  23  * Contributor(s):
  24  *   Rob Arnold <tellrob@gmail.com>
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  39
  40 #include "WindowHook.h"
  41 #include "nsWindow.h"
  42
  43 namespace mozilla {
  44 namespace widget {
  45
  46 nsresult
  47 WindowHook::AddHook(UINT nMsg, Callback callback, void *context) {
  48   MessageData *data = LookupOrCreate(nMsg);
  49
  50   if (!data)
  51     return NS_ERROR_OUT_OF_MEMORY;
  52
  53   // Ensure we don't overwrite another hook
  54   NS_ENSURE_TRUE(nsnull == data->hook.cb, NS_ERROR_UNEXPECTED);
  55
  56   data->hook = CallbackData(callback, context);
  57
  58   return NS_OK;
  59 }
  60
  61 nsresult
  62 WindowHook::RemoveHook(UINT nMsg, Callback callback, void *context) {
  63   CallbackData cbdata(callback, context);
  64   MessageData *data = Lookup(nMsg);
  65   if (!data)
  66     return NS_ERROR_UNEXPECTED;
  67   if (data->hook != cbdata)
  68     return NS_ERROR_UNEXPECTED;
  69   data->hook = CallbackData();
  70
  71   DeleteIfEmpty(data);
  72   return NS_OK;
  73 }
  74
  75 nsresult
  76 WindowHook::AddMonitor(UINT nMsg, Callback callback, void *context) {
  77   MessageData *data = LookupOrCreate(nMsg);
  78   return (data && data->monitors.AppendElement(CallbackData(callback, context)))
  79          ? NS_OK : NS_ERROR_OUT_OF_MEMORY;
  80 }
  81
  82 nsresult
  83 WindowHook::RemoveMonitor(UINT nMsg, Callback callback, void *context) {
  84   CallbackData cbdata(callback, context);
  85   MessageData *data = Lookup(nMsg);
  86   if (!data)
  87     return NS_ERROR_UNEXPECTED;
  88   CallbackDataArray::index_type idx = data->monitors.IndexOf(cbdata);
  89   if (idx == CallbackDataArray::NoIndex)
  90     return NS_ERROR_UNEXPECTED;
  91   data->monitors.RemoveElementAt(idx);
  92   DeleteIfEmpty(data);
  93   return NS_OK;
  94 }
  95
  96 WindowHook::MessageData *
  97 WindowHook::Lookup(UINT nMsg) {
  98   MessageDataArray::index_type idx;
  99   for (idx = 0; idx < mMessageData.Length(); idx++) {
 100     MessageData &data = mMessageData[idx];
 101     if (data.nMsg == nMsg)
 102       return &data;
 103   }
 104   return nsnull;
 105 }
 106
 107 WindowHook::MessageData *
 108 WindowHook::LookupOrCreate(UINT nMsg) {
 109   MessageData *data = Lookup(nMsg);
 110   if (!data) {
 111     data = mMessageData.AppendElement();
 112
 113     if (!data)
 114       return nsnull;
 115
 116     data->nMsg = nMsg;
 117   }
 118   return data;
 119 }
 120
 121 void
 122 WindowHook::DeleteIfEmpty(MessageData *data) {
 123   // Never remove a MessageData that has still a hook or monitor entries.
 124   if (data->hook || !data->monitors.IsEmpty())
 125     return;
 126
 127   MessageDataArray::index_type idx;
 128   idx = data - mMessageData.Elements();
 129   NS_ASSERTION(idx >= 0 && idx < mMessageData.Length(), "Attempted to delete MessageData that doesn't belong to this array!");
 130   mMessageData.RemoveElementAt(idx);
 131 }
 132
 133 PRBool
 134 WindowHook::Notify(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam,
 135                    LRESULT *aResult) {
 136   MessageData *data = Lookup(nMsg);
 137   if (!data)
 138     return PR_FALSE;
 139
 140   PRUint32 length = data->monitors.Length();
 141   for (PRUint32 midx = 0; midx < length; midx++) {
 142     data->monitors[midx].Invoke(hWnd, nMsg, wParam, lParam, aResult);
 143   }
 144
 145   return data->hook.Invoke(hWnd, nMsg, wParam, lParam, aResult);
 146 }
 147
 148 PRBool
 149 WindowHook::CallbackData::Invoke(HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam,
 150                                  LRESULT *aResult) {
 151   if (!cb)
 152     return PR_FALSE;
 153   return cb(context, hWnd, msg, wParam, lParam, aResult);
 154 }
 155 } // namespace widget
 156 } // namespace mozilla
 157