gecko-dev/js/src/jsfuninlines.h

91 строка
2.8 KiB
C++

/* -*- 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 jsfuninlines_h
#define jsfuninlines_h
#include "jsfun.h"
#include "vm/ScopeObject.h"
namespace js {
inline const char *
GetFunctionNameBytes(JSContext *cx, JSFunction *fun, JSAutoByteString *bytes)
{
JSAtom *atom = fun->atom();
if (atom)
return bytes->encodeLatin1(cx, atom);
return js_anonymous_str;
}
static inline JSObject *
SkipScopeParent(JSObject *parent)
{
if (!parent)
return nullptr;
while (parent->is<ScopeObject>())
parent = &parent->as<ScopeObject>().enclosingScope();
return parent;
}
inline bool
CanReuseFunctionForClone(JSContext *cx, HandleFunction fun)
{
if (!fun->hasSingletonType())
return false;
if (fun->isInterpretedLazy()) {
LazyScript *lazy = fun->lazyScript();
if (lazy->hasBeenCloned())
return false;
lazy->setHasBeenCloned();
} else {
JSScript *script = fun->nonLazyScript();
if (script->hasBeenCloned())
return false;
script->setHasBeenCloned();
}
return true;
}
inline JSFunction *
CloneFunctionObjectIfNotSingleton(JSContext *cx, HandleFunction fun, HandleObject parent,
NewObjectKind newKind = GenericObject)
{
/*
* For attempts to clone functions at a function definition opcode,
* try to avoid the the clone if the function has singleton type. This
* was called pessimistically, and we need to preserve the type's
* property that if it is singleton there is only a single object
* with its type in existence.
*
* For functions inner to run once lambda, it may be possible that
* the lambda runs multiple times and we repeatedly clone it. In these
* cases, fall through to CloneFunctionObject, which will deep clone
* the function's script.
*/
if (CanReuseFunctionForClone(cx, fun)) {
RootedObject obj(cx, SkipScopeParent(parent));
if (!JSObject::setParent(cx, fun, obj))
return nullptr;
fun->setEnvironment(parent);
return fun;
}
// These intermediate variables are needed to avoid link errors on some
// platforms. Sigh.
gc::AllocKind finalizeKind = JSFunction::FinalizeKind;
gc::AllocKind extendedFinalizeKind = JSFunction::ExtendedFinalizeKind;
gc::AllocKind kind = fun->isExtended()
? extendedFinalizeKind
: finalizeKind;
return CloneFunctionObject(cx, fun, parent, kind, newKind);
}
} /* namespace js */
#endif /* jsfuninlines_h */