webkit/renderer/cpp_bound_class.cc - platform/external/chromium_org - Git at Google

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 // This file contains definitions for CppBoundClass

 // Here's the control flow of a JS method getting forwarded to a class.
 // - Something calls our NPObject with a function like "Invoke".
 // - CppNPObject's static invoke() function forwards it to its attached
 //   CppBoundClass's Invoke() method.
 // - CppBoundClass has then overridden Invoke() to look up the function
 //   name in its internal map of methods, and then calls the appropriate
 //   method.

 #include "webkit/renderer/cpp_bound_class.h"

 #include "base/compiler_specific.h"
 #include "base/logging.h"
 #include "base/stl_util.h"
 #include "base/strings/utf_string_conversions.h"
 #include "third_party/WebKit/public/web/WebBindings.h"
 #include "third_party/WebKit/public/web/WebFrame.h"
 #include "third_party/WebKit/public/platform/WebString.h"

 using blink::WebBindings;
 using blink::WebFrame;

 namespace webkit_glue {

 namespace {

 class CppVariantPropertyCallback : public CppBoundClass::PropertyCallback {
  public:
   CppVariantPropertyCallback(CppVariant* value) : value_(value) { }

   virtual bool GetValue(CppVariant* value) OVERRIDE {
     value->Set(*value_);
     return true;
   }
   virtual bool SetValue(const CppVariant& value) OVERRIDE {
     value_->Set(value);
     return true;
   }

  private:
   CppVariant* value_;
 };

 class GetterPropertyCallback : public CppBoundClass::PropertyCallback {
 public:
   GetterPropertyCallback(const CppBoundClass::GetterCallback& callback)
       : callback_(callback) { }

   virtual bool GetValue(CppVariant* value) OVERRIDE {
     callback_.Run(value);
     return true;
   }

   virtual bool SetValue(const CppVariant& value) OVERRIDE {
     return false;
   }

 private:
   CppBoundClass::GetterCallback callback_;
 };

 }

 // Our special NPObject type.  We extend an NPObject with a pointer to a
 // CppBoundClass, which is just a C++ interface that we forward all NPObject
 // callbacks to.
 struct CppNPObject {
   NPObject parent;  // This must be the first field in the struct.
   CppBoundClass* bound_class;

   //
   // All following objects and functions are static, and just used to interface
   // with NPObject/NPClass.
   //

   // An NPClass associates static functions of CppNPObject with the
   // function pointers used by the JS runtime.
   static NPClass np_class_;

   // Allocate a new NPObject with the specified class.
   static NPObject* allocate(NPP npp, NPClass* aClass);

   // Free an object.
   static void deallocate(NPObject* obj);

   // Returns true if the C++ class associated with this NPObject exposes the
   // given property.  Called by the JS runtime.
   static bool hasProperty(NPObject *obj, NPIdentifier ident);

   // Returns true if the C++ class associated with this NPObject exposes the
   // given method.  Called by the JS runtime.
   static bool hasMethod(NPObject *obj, NPIdentifier ident);

   // If the given method is exposed by the C++ class associated with this
   // NPObject, invokes it with the given args and returns a result.  Otherwise,
   // returns "undefined" (in the JavaScript sense).  Called by the JS runtime.
   static bool invoke(NPObject *obj, NPIdentifier ident,
                      const NPVariant *args, uint32_t arg_count,
                      NPVariant *result);

   // If the given property is exposed by the C++ class associated with this
   // NPObject, returns its value.  Otherwise, returns "undefined" (in the
   // JavaScript sense).  Called by the JS runtime.
   static bool getProperty(NPObject *obj, NPIdentifier ident,
                           NPVariant *result);

   // If the given property is exposed by the C++ class associated with this
   // NPObject, sets its value.  Otherwise, does nothing. Called by the JS
   // runtime.
   static bool setProperty(NPObject *obj, NPIdentifier ident,
                           const NPVariant *value);
 };

 // Build CppNPObject's static function pointers into an NPClass, for use
 // in constructing NPObjects for the C++ classes.
 NPClass CppNPObject::np_class_ = {
   NP_CLASS_STRUCT_VERSION,
   CppNPObject::allocate,
   CppNPObject::deallocate,
   /* NPInvalidateFunctionPtr */ NULL,
   CppNPObject::hasMethod,
   CppNPObject::invoke,
   /* NPInvokeDefaultFunctionPtr */ NULL,
   CppNPObject::hasProperty,
   CppNPObject::getProperty,
   CppNPObject::setProperty,
   /* NPRemovePropertyFunctionPtr */ NULL
 };

 /* static */ NPObject* CppNPObject::allocate(NPP npp, NPClass* aClass) {
   CppNPObject* obj = new CppNPObject;
   // obj->parent will be initialized by the NPObject code calling this.
   obj->bound_class = NULL;
   return &obj->parent;
 }

 /* static */ void CppNPObject::deallocate(NPObject* np_obj) {
   CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
   delete obj;
 }

 /* static */ bool CppNPObject::hasMethod(NPObject* np_obj,
                                          NPIdentifier ident) {
   CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
   return obj->bound_class->HasMethod(ident);
 }

 /* static */ bool CppNPObject::hasProperty(NPObject* np_obj,
                                            NPIdentifier ident) {
   CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
   return obj->bound_class->HasProperty(ident);
 }

 /* static */ bool CppNPObject::invoke(NPObject* np_obj, NPIdentifier ident,
                                       const NPVariant* args, uint32_t arg_count,
                                       NPVariant* result) {
   CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
   return obj->bound_class->Invoke(ident, args, arg_count, result);
 }

 /* static */ bool CppNPObject::getProperty(NPObject* np_obj,
                                            NPIdentifier ident,
                                            NPVariant* result) {
   CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
   return obj->bound_class->GetProperty(ident, result);
 }

 /* static */ bool CppNPObject::setProperty(NPObject* np_obj,
                                            NPIdentifier ident,
                                            const NPVariant* value) {
   CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
   return obj->bound_class->SetProperty(ident, value);
 }

 CppBoundClass::CppBoundClass() : bound_to_frame_(false), npp_(new NPP_t) {
   WebBindings::registerObjectOwner(npp_.get());
 }

 CppBoundClass::~CppBoundClass() {
   STLDeleteValues(&properties_);

   // TODO(wez): Remove once crrev.com/14019005 lands.
   if (bound_to_frame_)
     WebBindings::unregisterObject(NPVARIANT_TO_OBJECT(self_variant_));

   WebBindings::unregisterObjectOwner(npp_.get());
 }

 bool CppBoundClass::HasMethod(NPIdentifier ident) const {
   return (methods_.find(ident) != methods_.end());
 }

 bool CppBoundClass::HasProperty(NPIdentifier ident) const {
   return (properties_.find(ident) != properties_.end());
 }

 bool CppBoundClass::Invoke(NPIdentifier ident,
                            const NPVariant* args,
                            size_t arg_count,
                            NPVariant* result) {
   MethodList::const_iterator method = methods_.find(ident);
   Callback callback;
   if (method == methods_.end()) {
     if (!fallback_callback_.is_null()) {
       callback = fallback_callback_;
     } else {
       VOID_TO_NPVARIANT(*result);
       return false;
     }
   } else {
     callback = method->second;
   }

   // Build a CppArgumentList argument vector from the NPVariants coming in.
   CppArgumentList cpp_args(arg_count);
   for (size_t i = 0; i < arg_count; i++)
     cpp_args[i].Set(args[i]);

   CppVariant cpp_result;
   callback.Run(cpp_args, &cpp_result);

   cpp_result.CopyToNPVariant(result);
   return true;
 }

 bool CppBoundClass::GetProperty(NPIdentifier ident, NPVariant* result) const {
   PropertyList::const_iterator callback = properties_.find(ident);
   if (callback == properties_.end()) {
     VOID_TO_NPVARIANT(*result);
     return false;
   }

   CppVariant cpp_value;
   if (!callback->second->GetValue(&cpp_value))
     return false;
   cpp_value.CopyToNPVariant(result);
   return true;
 }

 bool CppBoundClass::SetProperty(NPIdentifier ident,
                                 const NPVariant* value) {
   PropertyList::iterator callback = properties_.find(ident);
   if (callback == properties_.end())
     return false;

   CppVariant cpp_value;
   cpp_value.Set(*value);
   return (*callback).second->SetValue(cpp_value);
 }

 void CppBoundClass::BindCallback(const std::string& name,
                                  const Callback& callback) {
   NPIdentifier ident = WebBindings::getStringIdentifier(name.c_str());
   if (callback.is_null()) {
     methods_.erase(ident);
     return;
   }

   methods_[ident] = callback;
 }

 void CppBoundClass::BindGetterCallback(const std::string& name,
                                        const GetterCallback& callback) {
   PropertyCallback* property_callback = callback.is_null() ?
       NULL : new GetterPropertyCallback(callback);

   BindProperty(name, property_callback);
 }

 void CppBoundClass::BindProperty(const std::string& name, CppVariant* prop) {
   PropertyCallback* property_callback = prop == NULL ?
       NULL : new CppVariantPropertyCallback(prop);

   BindProperty(name, property_callback);
 }

 void CppBoundClass::BindProperty(const std::string& name,
                                  PropertyCallback* callback) {
   NPIdentifier ident = WebBindings::getStringIdentifier(name.c_str());
   PropertyList::iterator old_callback = properties_.find(ident);
   if (old_callback != properties_.end()) {
     delete old_callback->second;
     if (callback == NULL) {
       properties_.erase(old_callback);
       return;
     }
   }

   properties_[ident] = callback;
 }

 bool CppBoundClass::IsMethodRegistered(const std::string& name) const {
   NPIdentifier ident = WebBindings::getStringIdentifier(name.c_str());
   MethodList::const_iterator callback = methods_.find(ident);
   return (callback != methods_.end());
 }

 CppVariant* CppBoundClass::GetAsCppVariant() {
   if (!self_variant_.isObject()) {
     // Create an NPObject using our static NPClass.  The first argument has type
     // NPP, but is only used to track object ownership, so passing this is fine.
     NPObject* np_obj = WebBindings::createObject(
         npp_.get(), &CppNPObject::np_class_);
     CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
     obj->bound_class = this;
     self_variant_.Set(np_obj);
     WebBindings::releaseObject(np_obj);  // CppVariant takes the reference.
   }
   DCHECK(self_variant_.isObject());
   return &self_variant_;
 }

 void CppBoundClass::BindToJavascript(WebFrame* frame,
                                      const std::string& classname) {
   // BindToWindowObject will take its own reference to the NPObject, and clean
   // up after itself. It will also (indirectly) register the object with V8,
   // against an owner pointer we supply, so we must register that as an owner,
   // and unregister when we teardown.
   frame->bindToWindowObject(ASCIIToUTF16(classname),
                             NPVARIANT_TO_OBJECT(*GetAsCppVariant()));
   bound_to_frame_ = true;
 }

 }  // namespace webkit_glue
	// Copyright (c) 2012 The Chromium Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	// This file contains definitions for CppBoundClass

	// Here's the control flow of a JS method getting forwarded to a class.
	// - Something calls our NPObject with a function like "Invoke".
	// - CppNPObject's static invoke() function forwards it to its attached
	// CppBoundClass's Invoke() method.
	// - CppBoundClass has then overridden Invoke() to look up the function
	// name in its internal map of methods, and then calls the appropriate
	// method.

	#include "webkit/renderer/cpp_bound_class.h"

	#include "base/compiler_specific.h"
	#include "base/logging.h"
	#include "base/stl_util.h"
	#include "base/strings/utf_string_conversions.h"
	#include "third_party/WebKit/public/web/WebBindings.h"
	#include "third_party/WebKit/public/web/WebFrame.h"
	#include "third_party/WebKit/public/platform/WebString.h"

	using blink::WebBindings;
	using blink::WebFrame;

	namespace webkit_glue {

	namespace {

	class CppVariantPropertyCallback : public CppBoundClass::PropertyCallback {
	public:
	CppVariantPropertyCallback(CppVariant* value) : value_(value) { }

	virtual bool GetValue(CppVariant* value) OVERRIDE {
	value->Set(*value_);
	return true;
	}
	virtual bool SetValue(const CppVariant& value) OVERRIDE {
	value_->Set(value);
	return true;
	}

	private:
	CppVariant* value_;
	};

	class GetterPropertyCallback : public CppBoundClass::PropertyCallback {
	public:
	GetterPropertyCallback(const CppBoundClass::GetterCallback& callback)
	: callback_(callback) { }

	virtual bool GetValue(CppVariant* value) OVERRIDE {
	callback_.Run(value);
	return true;
	}

	virtual bool SetValue(const CppVariant& value) OVERRIDE {
	return false;
	}

	private:
	CppBoundClass::GetterCallback callback_;
	};

	}

	// Our special NPObject type. We extend an NPObject with a pointer to a
	// CppBoundClass, which is just a C++ interface that we forward all NPObject
	// callbacks to.
	struct CppNPObject {
	NPObject parent; // This must be the first field in the struct.
	CppBoundClass* bound_class;

	//
	// All following objects and functions are static, and just used to interface
	// with NPObject/NPClass.
	//

	// An NPClass associates static functions of CppNPObject with the
	// function pointers used by the JS runtime.
	static NPClass np_class_;

	// Allocate a new NPObject with the specified class.
	static NPObject* allocate(NPP npp, NPClass* aClass);

	// Free an object.
	static void deallocate(NPObject* obj);

	// Returns true if the C++ class associated with this NPObject exposes the
	// given property. Called by the JS runtime.
	static bool hasProperty(NPObject *obj, NPIdentifier ident);

	// Returns true if the C++ class associated with this NPObject exposes the
	// given method. Called by the JS runtime.
	static bool hasMethod(NPObject *obj, NPIdentifier ident);

	// If the given method is exposed by the C++ class associated with this
	// NPObject, invokes it with the given args and returns a result. Otherwise,
	// returns "undefined" (in the JavaScript sense). Called by the JS runtime.
	static bool invoke(NPObject *obj, NPIdentifier ident,
	const NPVariant *args, uint32_t arg_count,
	NPVariant *result);

	// If the given property is exposed by the C++ class associated with this
	// NPObject, returns its value. Otherwise, returns "undefined" (in the
	// JavaScript sense). Called by the JS runtime.
	static bool getProperty(NPObject *obj, NPIdentifier ident,
	NPVariant *result);

	// If the given property is exposed by the C++ class associated with this
	// NPObject, sets its value. Otherwise, does nothing. Called by the JS
	// runtime.
	static bool setProperty(NPObject *obj, NPIdentifier ident,
	const NPVariant *value);
	};

	// Build CppNPObject's static function pointers into an NPClass, for use
	// in constructing NPObjects for the C++ classes.
	NPClass CppNPObject::np_class_ = {
	NP_CLASS_STRUCT_VERSION,
	CppNPObject::allocate,
	CppNPObject::deallocate,
	/* NPInvalidateFunctionPtr */ NULL,
	CppNPObject::hasMethod,
	CppNPObject::invoke,
	/* NPInvokeDefaultFunctionPtr */ NULL,
	CppNPObject::hasProperty,
	CppNPObject::getProperty,
	CppNPObject::setProperty,
	/* NPRemovePropertyFunctionPtr */ NULL
	};

	/* static / NPObject CppNPObject::allocate(NPP npp, NPClass* aClass) {
	CppNPObject* obj = new CppNPObject;
	// obj->parent will be initialized by the NPObject code calling this.
	obj->bound_class = NULL;
	return &obj->parent;
	}

	/* static / void CppNPObject::deallocate(NPObject np_obj) {
	CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
	delete obj;
	}

	/* static / bool CppNPObject::hasMethod(NPObject np_obj,
	NPIdentifier ident) {
	CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
	return obj->bound_class->HasMethod(ident);
	}

	/* static / bool CppNPObject::hasProperty(NPObject np_obj,
	NPIdentifier ident) {
	CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
	return obj->bound_class->HasProperty(ident);
	}

	/* static / bool CppNPObject::invoke(NPObject np_obj, NPIdentifier ident,
	const NPVariant* args, uint32_t arg_count,
	NPVariant* result) {
	CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
	return obj->bound_class->Invoke(ident, args, arg_count, result);
	}

	/* static / bool CppNPObject::getProperty(NPObject np_obj,
	NPIdentifier ident,
	NPVariant* result) {
	CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
	return obj->bound_class->GetProperty(ident, result);
	}

	/* static / bool CppNPObject::setProperty(NPObject np_obj,
	NPIdentifier ident,
	const NPVariant* value) {
	CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
	return obj->bound_class->SetProperty(ident, value);
	}

	CppBoundClass::CppBoundClass() : bound_to_frame_(false), npp_(new NPP_t) {
	WebBindings::registerObjectOwner(npp_.get());
	}

	CppBoundClass::~CppBoundClass() {
	STLDeleteValues(&properties_);

	// TODO(wez): Remove once crrev.com/14019005 lands.
	if (bound_to_frame_)
	WebBindings::unregisterObject(NPVARIANT_TO_OBJECT(self_variant_));

	WebBindings::unregisterObjectOwner(npp_.get());
	}

	bool CppBoundClass::HasMethod(NPIdentifier ident) const {
	return (methods_.find(ident) != methods_.end());
	}

	bool CppBoundClass::HasProperty(NPIdentifier ident) const {
	return (properties_.find(ident) != properties_.end());
	}

	bool CppBoundClass::Invoke(NPIdentifier ident,
	const NPVariant* args,
	size_t arg_count,
	NPVariant* result) {
	MethodList::const_iterator method = methods_.find(ident);
	Callback callback;
	if (method == methods_.end()) {
	if (!fallback_callback_.is_null()) {
	callback = fallback_callback_;
	} else {
	VOID_TO_NPVARIANT(*result);
	return false;
	}
	} else {
	callback = method->second;
	}

	// Build a CppArgumentList argument vector from the NPVariants coming in.
	CppArgumentList cpp_args(arg_count);
	for (size_t i = 0; i < arg_count; i++)
	cpp_args[i].Set(args[i]);

	CppVariant cpp_result;
	callback.Run(cpp_args, &cpp_result);

	cpp_result.CopyToNPVariant(result);
	return true;
	}

	bool CppBoundClass::GetProperty(NPIdentifier ident, NPVariant* result) const {
	PropertyList::const_iterator callback = properties_.find(ident);
	if (callback == properties_.end()) {
	VOID_TO_NPVARIANT(*result);
	return false;
	}

	CppVariant cpp_value;
	if (!callback->second->GetValue(&cpp_value))
	return false;
	cpp_value.CopyToNPVariant(result);
	return true;
	}

	bool CppBoundClass::SetProperty(NPIdentifier ident,
	const NPVariant* value) {
	PropertyList::iterator callback = properties_.find(ident);
	if (callback == properties_.end())
	return false;

	CppVariant cpp_value;
	cpp_value.Set(*value);
	return (*callback).second->SetValue(cpp_value);
	}

	void CppBoundClass::BindCallback(const std::string& name,
	const Callback& callback) {
	NPIdentifier ident = WebBindings::getStringIdentifier(name.c_str());
	if (callback.is_null()) {
	methods_.erase(ident);
	return;
	}

	methods_[ident] = callback;
	}

	void CppBoundClass::BindGetterCallback(const std::string& name,
	const GetterCallback& callback) {
	PropertyCallback* property_callback = callback.is_null() ?
	NULL : new GetterPropertyCallback(callback);

	BindProperty(name, property_callback);
	}

	void CppBoundClass::BindProperty(const std::string& name, CppVariant* prop) {
	PropertyCallback* property_callback = prop == NULL ?
	NULL : new CppVariantPropertyCallback(prop);

	BindProperty(name, property_callback);
	}

	void CppBoundClass::BindProperty(const std::string& name,
	PropertyCallback* callback) {
	NPIdentifier ident = WebBindings::getStringIdentifier(name.c_str());
	PropertyList::iterator old_callback = properties_.find(ident);
	if (old_callback != properties_.end()) {
	delete old_callback->second;
	if (callback == NULL) {
	properties_.erase(old_callback);
	return;
	}
	}

	properties_[ident] = callback;
	}

	bool CppBoundClass::IsMethodRegistered(const std::string& name) const {
	NPIdentifier ident = WebBindings::getStringIdentifier(name.c_str());
	MethodList::const_iterator callback = methods_.find(ident);
	return (callback != methods_.end());
	}

	CppVariant* CppBoundClass::GetAsCppVariant() {
	if (!self_variant_.isObject()) {
	// Create an NPObject using our static NPClass. The first argument has type
	// NPP, but is only used to track object ownership, so passing this is fine.
	NPObject* np_obj = WebBindings::createObject(
	npp_.get(), &CppNPObject::np_class_);
	CppNPObject* obj = reinterpret_cast<CppNPObject*>(np_obj);
	obj->bound_class = this;
	self_variant_.Set(np_obj);
	WebBindings::releaseObject(np_obj); // CppVariant takes the reference.
	}
	DCHECK(self_variant_.isObject());
	return &self_variant_;
	}

	void CppBoundClass::BindToJavascript(WebFrame* frame,
	const std::string& classname) {
	// BindToWindowObject will take its own reference to the NPObject, and clean
	// up after itself. It will also (indirectly) register the object with V8,
	// against an owner pointer we supply, so we must register that as an owner,
	// and unregister when we teardown.
	frame->bindToWindowObject(ASCIIToUTF16(classname),
	NPVARIANT_TO_OBJECT(*GetAsCppVariant()));
	bound_to_frame_ = true;
	}

	} // namespace webkit_glue