third_party/WebKit/Source/platform/EventDispatchForbiddenScope.h

   1 // Copyright 2014 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef EventDispatchForbiddenScope_h
   6 #define EventDispatchForbiddenScope_h
   7
   8 #include "platform/PlatformExport.h"
   9 #include "wtf/Assertions.h"
  10 #include "wtf/MainThread.h"
  11 #include "wtf/TemporaryChange.h"
  12
  13 namespace blink {
  14
  15 #if ENABLE(ASSERT)
  16
  17 class EventDispatchForbiddenScope {
  18 public:
  19     EventDispatchForbiddenScope()
  20     {
  21         ASSERT(isMainThread());
  22         ++s_count;
  23     }
  24
  25     ~EventDispatchForbiddenScope()
  26     {
  27         ASSERT(isMainThread());
  28         ASSERT(s_count);
  29         --s_count;
  30     }
  31
  32     static bool isEventDispatchForbidden()
  33     {
  34         if (!isMainThread())
  35             return false;
  36         return s_count;
  37     }
  38
  39     class AllowUserAgentEvents {
  40     public:
  41         AllowUserAgentEvents()
  42             : m_change(s_count, 0)
  43         {
  44             ASSERT(isMainThread());
  45         }
  46
  47         ~AllowUserAgentEvents()
  48         {
  49             ASSERT(!s_count);
  50         }
  51
  52         TemporaryChange<unsigned> m_change;
  53     };
  54
  55 private:
  56     PLATFORM_EXPORT static unsigned s_count;
  57 };
  58
  59 #else
  60
  61 class EventDispatchForbiddenScope {
  62 public:
  63     EventDispatchForbiddenScope() { }
  64
  65     class AllowUserAgentEvents {
  66     public:
  67         AllowUserAgentEvents() { }
  68     };
  69 };
  70
  71 #endif // ENABLE(ASSERT)
  72
  73 } // namespace blink
  74
  75 #endif // EventDispatchForbiddenScope_h