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|
$$ This is a pump file for generating file templates. Pump is a python
$$ script that is part of the Google Test suite of utilities. Description
$$ can be found here:
$$
$$ http://code.google.com/p/googletest/wiki/PumpManual
$$
#ifndef GIN_FUNCTION_TEMPLATE_H_
#define GIN_FUNCTION_TEMPLATE_H_
$var MAX_ARITY = 4
// Copyright 2013 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.
#include "base/callback.h"
#include "base/logging.h"
#include "gin/arguments.h"
#include "gin/converter.h"
#include "gin/gin_export.h"
#include "gin/handle.h"
#include "gin/public/gin_embedders.h"
#include "gin/public/wrapper_info.h"
#include "gin/wrappable.h"
#include "v8/include/v8.h"
namespace gin {
class PerIsolateData;
enum CreateFunctionTemplateFlags {
HolderIsFirstArgument = 1 << 0,
};
namespace internal {
template<typename T>
struct CallbackParamTraits {
typedef T LocalType;
};
template<typename T>
struct CallbackParamTraits<const T&> {
typedef T LocalType;
};
template<typename T>
struct CallbackParamTraits<const T*> {
typedef T* LocalType;
};
// CallbackHolder and CallbackHolderBase are used to pass a base::Callback from
// CreateFunctionTemplate through v8 (via v8::FunctionTemplate) to
// DispatchToCallback, where it is invoked.
//
// v8::FunctionTemplate only supports passing void* as data so how do we know
// when to delete the base::Callback? That's where CallbackHolderBase comes in.
// It inherits from Wrappable, which delete itself when both (a) the refcount
// via base::RefCounted has dropped to zero, and (b) there are no more
// JavaScript references in V8.
// This simple base class is used so that we can share a single object template
// among every CallbackHolder instance.
class GIN_EXPORT CallbackHolderBase : public Wrappable<CallbackHolderBase> {
public:
static WrapperInfo kWrapperInfo;
protected:
virtual ~CallbackHolderBase() {}
};
template<typename Sig>
class CallbackHolder : public CallbackHolderBase {
public:
CallbackHolder(const base::Callback<Sig>& callback, int flags)
: callback(callback), flags(flags) {}
base::Callback<Sig> callback;
int flags;
private:
virtual ~CallbackHolder() {}
};
// This set of templates invokes a base::Callback, converts the return type to a
// JavaScript value, and returns that value to script via the provided
// gin::Arguments object.
//
// In C++, you can declare the function foo(void), but you can't pass a void
// expression to foo. As a result, we must specialize the case of Callbacks that
// have the void return type.
$range ARITY 0..MAX_ARITY
$for ARITY [[
$var INV_ARITY = MAX_ARITY - ARITY
$range ARG 1..INV_ARITY
$range VOID INV_ARITY+1..MAX_ARITY
$if ARITY == 0 [[
template<typename R$for ARG [[, typename P$(ARG) = void]]>
struct Invoker {
]] $else [[
template<typename R$for ARG [[, typename P$(ARG)]]>
struct Invoker<R$for ARG [[, P$(ARG)]]$for VOID [[, void]]> {
]]
inline static void Go(
Arguments* args,
const base::Callback<R($for ARG , [[P$(ARG)]])>& callback$for ARG [[,
const P$(ARG)& a$(ARG)]]) {
args->Return(callback.Run($for ARG, [[a$(ARG)]]));
}
};
template<$for ARG , [[typename P$(ARG)]]>
struct Invoker<void$for ARG [[, P$(ARG)]]$for VOID [[, void]]> {
inline static void Go(
Arguments* args,
const base::Callback<void($for ARG , [[P$(ARG)]])>& callback$for ARG [[,
const P$(ARG)& a$(ARG)]]) {
callback.Run($for ARG, [[a$(ARG)]]);
}
};
]]
template<typename T>
bool GetNextArgument(Arguments* args, int create_flags, bool is_first,
T* result) {
if (is_first && (create_flags & HolderIsFirstArgument) != 0) {
return args->GetHolder(result);
} else {
return args->GetNext(result);
}
}
// For advanced use cases, we allow callers to request the unparsed Arguments
// object and poke around in it directly.
inline bool GetNextArgument(Arguments* args, int create_flags, bool is_first,
Arguments* result) {
*result = *args;
return true;
}
// DispatchToCallback converts all the JavaScript arguments to C++ types and
// invokes the base::Callback.
template<typename Sig>
struct Dispatcher {
};
$range ARITY 0..MAX_ARITY
$for ARITY [[
$range ARG 1..ARITY
template<typename R$for ARG [[, typename P$(ARG)]]>
struct Dispatcher<R($for ARG , [[P$(ARG)]])> {
static void DispatchToCallback(
const v8::FunctionCallbackInfo<v8::Value>& info) {
Arguments args(info);
CallbackHolderBase* holder_base = NULL;
CHECK(args.GetData(&holder_base));
typedef CallbackHolder<R($for ARG , [[P$(ARG)]])> HolderT;
HolderT* holder = static_cast<HolderT*>(holder_base);
$if ARITY != 0 [[
$for ARG [[ typename CallbackParamTraits<P$(ARG)>::LocalType a$(ARG);
]]
if ($for ARG ||
[[!GetNextArgument(&args, holder->flags, $if ARG == 1 [[true]] $else [[false]], &a$(ARG))]]) {
args.ThrowError();
return;
}
]]
Invoker<R$for ARG [[, P$(ARG)]]>::Go(&args, holder->callback$for ARG [[, a$(ARG)]]);
}
};
]]
} // namespace internal
// This should be called once per-isolate to initialize the function template
// system.
GIN_EXPORT void InitFunctionTemplates(PerIsolateData* isolate_data);
// CreateFunctionTemplate creates a v8::FunctionTemplate that will create
// JavaScript functions that execute a provided C++ function or base::Callback.
// JavaScript arguments are automatically converted via gin::Converter, as is
// the return value of the C++ function, if any.
template<typename Sig>
v8::Local<v8::FunctionTemplate> CreateFunctionTemplate(
v8::Isolate* isolate, const base::Callback<Sig> callback,
int callback_flags = 0) {
typedef internal::CallbackHolder<Sig> HolderT;
gin::Handle<HolderT> holder = CreateHandle(
isolate, new HolderT(callback, callback_flags));
return v8::FunctionTemplate::New(
&internal::Dispatcher<Sig>::DispatchToCallback,
ConvertToV8<internal::CallbackHolderBase*>(isolate, holder.get()));
}
} // namespace gin
#endif // GIN_FUNCTION_TEMPLATE_H_
|
