gears/base/ie/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_IE_MODULE_WRAPPER_H__
  27 #define GEARS_BASE_IE_MODULE_WRAPPER_H__
  28
  29 #include <assert.h>
  30 #include "gears/base/common/base_class.h"
  31 #include "gears/base/common/common.h"
  32 #include "gears/base/common/dispatcher.h"
  33 #include "gears/base/common/js_types.h"
  34 #include "gears/base/ie/atl_headers.h"
  35 #include "gears/third_party/scoped_ptr/scoped_ptr.h"
  36
  37 // Represents the bridge between the JavaScript engine and a Gears module. A
  38 // ModuleWrapper wraps each Gears module instance and exposes its methods to
  39 // JavaScript. The wrapper is ref-counted and has ownership of the module so
  40 // that when all references are released, the module is destroyed.
  41 class ATL_NO_VTABLE ModuleWrapper
  42     : public ModuleWrapperBaseClass,
  43       public IDispatch,
  44       public CComObjectRootEx<CComMultiThreadModel>,
  45       public CComCoClass<ModuleWrapper> {
  46  public:
  47   BEGIN_COM_MAP(ModuleWrapper)
  48     COM_INTERFACE_ENTRY(IDispatch)
  49   END_COM_MAP()
  50
  51   DECLARE_NOT_AGGREGATABLE(ModuleWrapper)
  52   DECLARE_PROTECT_FINAL_CONSTRUCT()
  53
  54   ModuleWrapper() {
  55     VariantInit(&token_);
  56     token_.vt = VT_DISPATCH;
  57     token_.pdispVal = const_cast<ModuleWrapper *>(this);
  58   }
  59
  60   ~ModuleWrapper() {}
  61
  62   static JsCallContext *PeekJsCallContext();
  63
  64   // IDispatch
  65   STDMETHOD(GetTypeInfoCount)(unsigned int FAR* retval) {
  66     // JavaScript does not call this
  67     assert(false);
  68     return E_NOTIMPL;
  69   }
  70
  71   STDMETHOD(GetTypeInfo)(unsigned int index, LCID lcid,
  72                          ITypeInfo FAR* FAR* retval) {
  73     // JavaScript does not call this
  74     assert(false);
  75     return E_NOTIMPL;
  76   }
  77
  78   STDMETHOD(GetIDsOfNames)(REFIID iid, OLECHAR FAR* FAR* names,
  79                            unsigned int num_names, LCID lcid,
  80                            DISPID FAR* retval);
  81   STDMETHOD(Invoke)(DISPID member_id, REFIID iid, LCID lcid, WORD flags,
  82                     DISPPARAMS FAR* params, VARIANT FAR* retval,
  83                     EXCEPINFO FAR* exception,
  84                     unsigned int FAR* arg_error_index);
  85
  86   // ModuleWrapperBaseClass
  87   // Returns a token for this wrapper class that can be returned via the
  88   // JsRunnerInterface.
  89   virtual JsToken GetWrapperToken() const {
  90     return token_;
  91   }
  92
  93   // Gets the Dispatcher for this module.
  94   virtual DispatcherInterface *GetDispatcher() const {
  95     assert(dispatcher_.get());
  96     return dispatcher_.get();
  97   }
  98
  99   virtual void AddReference() {
 100     AddRef();
 101   }
 102
 103   virtual void RemoveReference() {
 104     Release();
 105   }
 106
 107   void Init(ModuleImplBaseClassVirtual *impl, DispatcherInterface *dispatcher) {
 108     assert(!impl_.get());
 109     assert(impl);
 110     impl_.reset(impl);
 111
 112     assert(!dispatcher_.get());
 113     assert(dispatcher);
 114     dispatcher_.reset(dispatcher);
 115   }
 116
 117  private:
 118   scoped_ptr<ModuleImplBaseClassVirtual> impl_;
 119   scoped_ptr<DispatcherInterface> dispatcher_;
 120   VARIANT token_;
 121
 122   DISALLOW_EVIL_CONSTRUCTORS(ModuleWrapper);
 123 };
 124
 125
 126
 127 // Creates an instance of the class and its wrapper.
 128 template<class GearsClass>
 129 GearsClass *CreateModule(JsRunnerInterface *js_runner) {
 130   CComObject<ModuleWrapper> *module_wrapper;
 131   HRESULT hr = CComObject<ModuleWrapper>::CreateInstance(&module_wrapper);
 132   if (FAILED(hr)) return NULL;
 133
 134   GearsClass *impl = new GearsClass();
 135   Dispatcher<GearsClass> *dispatcher = new Dispatcher<GearsClass>(impl);
 136
 137   module_wrapper->Init(impl, dispatcher);
 138   impl->SetJsWrapper(module_wrapper);
 139   impl->AddReference();
 140
 141   return impl;
 142 }
 143
 144 #endif  //  GEARS_BASE_IE_MODULE_WRAPPER_H__