Symbol*
Symbol::for_(js::ExclusiveContext* cx, HandleString description)
{
JSAtom* atom = AtomizeString(cx, description);
if (!atom)
return nullptr;
AutoLockForExclusiveAccess lock(cx);
SymbolRegistry& registry = cx->symbolRegistry(lock);
SymbolRegistry::AddPtr p = registry.lookupForAdd(atom);
if (p)
return *p;
AutoCompartment ac(cx, cx->atomsCompartment(lock), &lock);
Symbol* sym = newInternal(cx, SymbolCode::InSymbolRegistry, atom->hash(), atom, lock);
if (!sym)
return nullptr;
// p is still valid here because we have held the lock since the
// lookupForAdd call, and newInternal can't GC.
if (!registry.add(p, sym)) {
// SystemAllocPolicy does not report OOM.
ReportOutOfMemory(cx);
return nullptr;
}
return sym;
}
Symbol*
Symbol::for_(JSContext* cx, HandleString description)
{
JSAtom* atom = AtomizeString(cx, description);
if (!atom)
return nullptr;
AutoLockForExclusiveAccess lock(cx);
SymbolRegistry& registry = cx->symbolRegistry(lock);
SymbolRegistry::AddPtr p = registry.lookupForAdd(atom);
if (p) {
cx->markAtom(*p);
return *p;
}
Symbol* sym;
{
AutoAtomsCompartment ac(cx, lock);
// Rehash the hash of the atom to give the corresponding symbol a hash
// that is different than the hash of the corresponding atom.
HashNumber hash = mozilla::HashGeneric(atom->hash());
sym = newInternal(cx, SymbolCode::InSymbolRegistry, hash, atom, lock);
if (!sym)
return nullptr;
// p is still valid here because we have held the lock since the
// lookupForAdd call, and newInternal can't GC.
if (!registry.add(p, sym)) {
// SystemAllocPolicy does not report OOM.
ReportOutOfMemory(cx);
return nullptr;
}
}
cx->markAtom(sym);
return sym;
}
