Bug 909623 (part 4) - Create js/CallNonGenericMethod.h and vm/CallNonGenericMethod.cpp. r=luke.

--HG--
extra : rebase_source : 5a81a57ea81227c995d7fd0933c226ac10384991
This commit is contained in:
Nicholas Nethercote 2013-08-26 21:39:38 -07:00
parent 6c7bc00e70
commit 59fc32f043
7 changed files with 155 additions and 119 deletions

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@ -0,0 +1,117 @@
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef js_CallNonGenericMethod_h
#define js_CallNonGenericMethod_h
#include "jstypes.h"
#include "js/CallArgs.h"
namespace JS {
// Returns true if |v| is considered an acceptable this-value.
typedef bool (*IsAcceptableThis)(Handle<Value> v);
// Implements the guts of a method; guaranteed to be provided an acceptable
// this-value, as determined by a corresponding IsAcceptableThis method.
typedef bool (*NativeImpl)(JSContext *cx, CallArgs args);
namespace detail {
// DON'T CALL THIS DIRECTLY. It's for use only by CallNonGenericMethod!
extern JS_PUBLIC_API(bool)
CallMethodIfWrapped(JSContext *cx, IsAcceptableThis test, NativeImpl impl, CallArgs args);
} // namespace detail
// Methods usually act upon |this| objects only from a single global object and
// compartment. Sometimes, however, a method must act upon |this| values from
// multiple global objects or compartments. In such cases the |this| value a
// method might see will be wrapped, such that various access to the object --
// to its class, its private data, its reserved slots, and so on -- will not
// work properly without entering that object's compartment. This method
// implements a solution to this problem.
//
// To implement a method that accepts |this| values from multiple compartments,
// define two functions. The first function matches the IsAcceptableThis type
// and indicates whether the provided value is an acceptable |this| for the
// method; it must be a pure function only of its argument.
//
// static JSClass AnswerClass = { ... };
//
// static bool
// IsAnswerObject(const Value &v)
// {
// if (!v.isObject())
// return false;
// return JS_GetClass(&v.toObject()) == &AnswerClass;
// }
//
// The second function implements the NativeImpl signature and defines the
// behavior of the method when it is provided an acceptable |this| value.
// Aside from some typing niceties -- see the CallArgs interface for details --
// its interface is the same as that of JSNative.
//
// static bool
// answer_getAnswer_impl(JSContext *cx, JS::CallArgs args)
// {
// args.rval().setInt32(42);
// return true;
// }
//
// The implementation function is guaranteed to be called *only* with a |this|
// value which is considered acceptable.
//
// Now to implement the actual method, write a JSNative that calls the method
// declared below, passing the appropriate template and runtime arguments.
//
// static bool
// answer_getAnswer(JSContext *cx, unsigned argc, JS::Value *vp)
// {
// JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
// return JS::CallNonGenericMethod<IsAnswerObject, answer_getAnswer_impl>(cx, args);
// }
//
// Note that, because they are used as template arguments, the predicate
// and implementation functions must have external linkage. (This is
// unfortunate, but GCC wasn't inlining things as one would hope when we
// passed them as function arguments.)
//
// JS::CallNonGenericMethod will test whether |args.thisv()| is acceptable. If
// it is, it will call the provided implementation function, which will return
// a value and indicate success. If it is not, it will attempt to unwrap
// |this| and call the implementation function on the unwrapped |this|. If
// that succeeds, all well and good. If it doesn't succeed, a TypeError will
// be thrown.
//
// Note: JS::CallNonGenericMethod will only work correctly if it's called in
// tail position in a JSNative. Do not call it from any other place.
//
template<IsAcceptableThis Test, NativeImpl Impl>
JS_ALWAYS_INLINE bool
CallNonGenericMethod(JSContext *cx, CallArgs args)
{
HandleValue thisv = args.thisv();
if (Test(thisv))
return Impl(cx, args);
return detail::CallMethodIfWrapped(cx, Test, Impl, args);
}
JS_ALWAYS_INLINE bool
CallNonGenericMethod(JSContext *cx, IsAcceptableThis Test, NativeImpl Impl, CallArgs args)
{
HandleValue thisv = args.thisv();
if (Test(thisv))
return Impl(cx, args);
return detail::CallMethodIfWrapped(cx, Test, Impl, args);
}
} // namespace JS
#endif /* js_CallNonGenericMethod_h */

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@ -100,23 +100,6 @@ using mozilla::PodZero;
using js::frontend::Parser;
bool
JS::detail::CallMethodIfWrapped(JSContext *cx, IsAcceptableThis test, NativeImpl impl,
CallArgs args)
{
HandleValue thisv = args.thisv();
JS_ASSERT(!test(thisv));
if (thisv.isObject()) {
JSObject &thisObj = args.thisv().toObject();
if (thisObj.is<ProxyObject>())
return Proxy::nativeCall(cx, test, impl, args);
}
ReportIncompatible(cx, args);
return false;
}
#ifdef HAVE_VA_LIST_AS_ARRAY
#define JS_ADDRESSOF_VA_LIST(ap) ((va_list *)(ap))
#else

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@ -24,6 +24,7 @@
#include "jspubtd.h"
#include "js/CallArgs.h"
#include "js/CallNonGenericMethod.h"
#include "js/Class.h"
#include "js/HashTable.h"
#include "js/Id.h"
@ -646,108 +647,6 @@ class JS_PUBLIC_API(CustomAutoRooter) : private AutoGCRooter
MOZ_DECL_USE_GUARD_OBJECT_NOTIFIER
};
/* Returns true if |v| is considered an acceptable this-value. */
typedef bool (*IsAcceptableThis)(JS::Handle<JS::Value> v);
/*
* Implements the guts of a method; guaranteed to be provided an acceptable
* this-value, as determined by a corresponding IsAcceptableThis method.
*/
typedef bool (*NativeImpl)(JSContext *cx, CallArgs args);
namespace detail {
/* DON'T CALL THIS DIRECTLY. It's for use only by CallNonGenericMethod! */
extern JS_PUBLIC_API(bool)
CallMethodIfWrapped(JSContext *cx, IsAcceptableThis test, NativeImpl impl, CallArgs args);
} /* namespace detail */
/*
* Methods usually act upon |this| objects only from a single global object and
* compartment. Sometimes, however, a method must act upon |this| values from
* multiple global objects or compartments. In such cases the |this| value a
* method might see will be wrapped, such that various access to the object --
* to its class, its private data, its reserved slots, and so on -- will not
* work properly without entering that object's compartment. This method
* implements a solution to this problem.
*
* To implement a method that accepts |this| values from multiple compartments,
* define two functions. The first function matches the IsAcceptableThis type
* and indicates whether the provided value is an acceptable |this| for the
* method; it must be a pure function only of its argument.
*
* static JSClass AnswerClass = { ... };
*
* static bool
* IsAnswerObject(const Value &v)
* {
* if (!v.isObject())
* return false;
* return JS_GetClass(&v.toObject()) == &AnswerClass;
* }
*
* The second function implements the NativeImpl signature and defines the
* behavior of the method when it is provided an acceptable |this| value.
* Aside from some typing niceties -- see the CallArgs interface for details --
* its interface is the same as that of JSNative.
*
* static bool
* answer_getAnswer_impl(JSContext *cx, JS::CallArgs args)
* {
* args.rval().setInt32(42);
* return true;
* }
*
* The implementation function is guaranteed to be called *only* with a |this|
* value which is considered acceptable.
*
* Now to implement the actual method, write a JSNative that calls the method
* declared below, passing the appropriate template and runtime arguments.
*
* static bool
* answer_getAnswer(JSContext *cx, unsigned argc, JS::Value *vp)
* {
* JS::CallArgs args = JS::CallArgsFromVp(argc, vp);
* return JS::CallNonGenericMethod<IsAnswerObject, answer_getAnswer_impl>(cx, args);
* }
*
* Note that, because they are used as template arguments, the predicate
* and implementation functions must have external linkage. (This is
* unfortunate, but GCC wasn't inlining things as one would hope when we
* passed them as function arguments.)
*
* JS::CallNonGenericMethod will test whether |args.thisv()| is acceptable. If
* it is, it will call the provided implementation function, which will return
* a value and indicate success. If it is not, it will attempt to unwrap
* |this| and call the implementation function on the unwrapped |this|. If
* that succeeds, all well and good. If it doesn't succeed, a TypeError will
* be thrown.
*
* Note: JS::CallNonGenericMethod will only work correctly if it's called in
* tail position in a JSNative. Do not call it from any other place.
*/
template<IsAcceptableThis Test, NativeImpl Impl>
JS_ALWAYS_INLINE bool
CallNonGenericMethod(JSContext *cx, CallArgs args)
{
HandleValue thisv = args.thisv();
if (Test(thisv))
return Impl(cx, args);
return detail::CallMethodIfWrapped(cx, Test, Impl, args);
}
JS_ALWAYS_INLINE bool
CallNonGenericMethod(JSContext *cx, IsAcceptableThis Test, NativeImpl Impl, CallArgs args)
{
HandleValue thisv = args.thisv();
if (Test(thisv))
return Impl(cx, args);
return detail::CallMethodIfWrapped(cx, Test, Impl, args);
}
} /* namespace JS */
/************************************************************************/

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@ -16,6 +16,7 @@
#include "jspubtd.h"
#include "js/CallArgs.h"
#include "js/CallNonGenericMethod.h"
/*
* This macro checks if the stack pointer has exceeded a given limit. If

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@ -12,6 +12,8 @@
#include "jsapi.h"
#include "jsfriendapi.h"
#include "js/CallNonGenericMethod.h"
namespace js {
class RegExpGuard;

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@ -59,6 +59,7 @@ if CONFIG['HAVE_DTRACE']:
EXPORTS.js += [
'../public/Anchor.h',
'../public/CallArgs.h',
'../public/CallNonGenericMethod.h',
'../public/CharacterEncoding.h',
'../public/Class.h',
'../public/Date.h',
@ -85,6 +86,7 @@ CPP_SOURCES += [
'BinaryData.cpp',
'BytecodeCompiler.cpp',
'BytecodeEmitter.cpp',
'CallNonGenericMethod.cpp',
'CharacterEncoding.cpp',
'DateTime.cpp',
'Debugger.cpp',

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@ -0,0 +1,32 @@
/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
* vim: set ts=8 sts=4 et sw=4 tw=99:
* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "js/CallNonGenericMethod.h"
#include "jsfun.h"
#include "jsobj.h"
#include "vm/ProxyObject.h"
using namespace js;
bool
JS::detail::CallMethodIfWrapped(JSContext *cx, IsAcceptableThis test, NativeImpl impl,
CallArgs args)
{
HandleValue thisv = args.thisv();
JS_ASSERT(!test(thisv));
if (thisv.isObject()) {
JSObject &thisObj = args.thisv().toObject();
if (thisObj.is<ProxyObject>())
return Proxy::nativeCall(cx, test, impl, args);
}
ReportIncompatible(cx, args);
return false;
}