gears/base/npapi/module_wrapper.h

   1 // Copyright 2007, Google Inc.
   2 //
   3 // Redistribution and use in source and binary forms, with or without
   4 // modification, are permitted provided that the following conditions are met:
   5 //
   6 //  1. Redistributions of source code must retain the above copyright notice,
   7 //     this list of conditions and the following disclaimer.
   8 //  2. Redistributions in binary form must reproduce the above copyright notice,
   9 //     this list of conditions and the following disclaimer in the documentation
  10 //     and/or other materials provided with the distribution.
  11 //  3. Neither the name of Google Inc. nor the names of its contributors may be
  12 //     used to endorse or promote products derived from this software without
  13 //     specific prior written permission.
  14 //
  15 // THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED
  16 // WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
  17 // MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
  18 // EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
  19 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
  20 // PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
  21 // OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
  22 // WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
  23 // OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
  24 // ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  25
  26 #ifndef GEARS_BASE_NPAPI_MODULE_WRAPPER_H__
  27 #define GEARS_BASE_NPAPI_MODULE_WRAPPER_H__
  28
  29 #include "gears/base/common/base_class.h"
  30 #include "gears/base/npapi/browser_utils.h"
  31 #include "gears/base/npapi/plugin.h"
  32 #include "gears/third_party/scoped_ptr/scoped_ptr.h"
  33
  34 // Represents the bridge between the JavaScript engine and a Gears module. A
  35 // ModuleWrapper wraps each Gears module instance and exposes its methods to
  36 // JavaScript. The wrapper has ownership of the module, so that when the
  37 // JavaScript engine decides to destroy the wrapper, the module itself is
  38 // destroyed.
  39 class ModuleWrapper
  40     : public PluginBase,
  41       public ModuleWrapperBaseClass {
  42  public:
  43   ModuleWrapper(NPP instance) : PluginBase(instance) {
  44   }
  45
  46   void Init(ModuleImplBaseClass *impl, DispatcherInterface *dispatcher) {
  47     PluginBase::Init(dispatcher);
  48     impl_.reset(impl);
  49     impl_->SetJsWrapper(this);
  50     dispatcher_.reset(dispatcher);
  51   }
  52
  53   virtual JsToken GetWrapperToken() const {
  54     NPVariant token;
  55     OBJECT_TO_NPVARIANT(const_cast<ModuleWrapper *>(this), token);
  56     return token;
  57   }
  58   virtual void AddRef() { NPN_RetainObject(this); }
  59   virtual void Release() { NPN_ReleaseObject(this); }
  60
  61  protected:
  62   scoped_ptr<ModuleImplBaseClass> impl_;
  63   scoped_ptr<DispatcherInterface> dispatcher_;
  64
  65  private:
  66   DISALLOW_EVIL_CONSTRUCTORS(ModuleWrapper);
  67 };
  68
  69
  70 // Creates an instance of the class and its wrapper.
  71 template<class GearsClass>
  72 GearsClass *CreateModule<GearsClass>(JsContextPtr context) {
  73   ModuleWrapper *wrapper = static_cast<ModuleWrapper *>(
  74       NPN_CreateObject(context, GetNPClass<ModuleWrapper>()));
  75
  76   if (!wrapper) {
  77     BrowserUtils::SetJsException(
  78         STRING16(L"Failed to create requested object."));
  79     return NULL;
  80   }
  81
  82   GearsClass *impl = new GearsClass;
  83   wrapper->Init(impl, new Dispatcher<GearsClass>(impl));
  84   return impl;
  85 }
  86
  87 // Used to set up a Gears module's wrapper.
  88 #define DECLARE_GEARS_WRAPPER(GearsClass) \
  89 DECLARE_DISPATCHER(GearsClass)
  90
  91 #endif // GEARS_BASE_NPAPI_MODULE_WRAPPER_H__