From 6bf0a5cb5034a7e684dcc3500e841785237ce2dd Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 19:32:43 +0200 Subject: Adding upstream version 1:115.7.0. Signed-off-by: Daniel Baumann --- js/public/Object.h | 147 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 147 insertions(+) create mode 100644 js/public/Object.h (limited to 'js/public/Object.h') diff --git a/js/public/Object.h b/js/public/Object.h new file mode 100644 index 0000000000..c7c5e3c617 --- /dev/null +++ b/js/public/Object.h @@ -0,0 +1,147 @@ +/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- + * vim: set ts=8 sts=2 et sw=2 tw=80: + * 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_public_Object_h +#define js_public_Object_h + +#include "js/shadow/Object.h" // JS::shadow::Object + +#include "mozilla/Assertions.h" // MOZ_ASSERT + +#include // size_t +#include // uint32_t + +#include "jstypes.h" // JS_PUBLIC_API + +#include "js/Class.h" // js::ESClass, JSCLASS_RESERVED_SLOTS +#include "js/Realm.h" // JS::GetCompartmentForRealm +#include "js/RootingAPI.h" // JS::{,Mutable}Handle +#include "js/Value.h" // JS::Value + +struct JS_PUBLIC_API JSContext; +class JS_PUBLIC_API JSObject; + +namespace JS { + +class JS_PUBLIC_API Compartment; + +/** + * Determine the ECMAScript "class" -- Date, String, RegExp, and all the other + * builtin object types (described in ECMAScript in terms of an objecting having + * "an [[ArrayBufferData]] internal slot" or similar language for other kinds of + * object -- of the provided object. + * + * If this function is passed a wrapper that can be unwrapped, the determination + * is performed on that object. If the wrapper can't be unwrapped, and it's not + * a wrapper that prefers to treat this operation as a failure, this function + * will indicate that the object is |js::ESClass::Other|. + */ +extern JS_PUBLIC_API bool GetBuiltinClass(JSContext* cx, Handle obj, + js::ESClass* cls); + +/** Get the |JSClass| of an object. */ +inline const JSClass* GetClass(const JSObject* obj) { + return reinterpret_cast(obj)->shape->base->clasp; +} + +/** + * Get the |JS::Compartment*| of an object. + * + * Note that the compartment of an object in this realm, that is a + * cross-compartment wrapper around an object from another realm, is the + * compartment of this realm. + */ +static MOZ_ALWAYS_INLINE Compartment* GetCompartment(JSObject* obj) { + Realm* realm = reinterpret_cast(obj)->shape->base->realm; + return GetCompartmentForRealm(realm); +} + +/** + * Get the value stored in a reserved slot in an object. + * + * If |obj| is known to be a proxy and you're willing to use friend APIs, + * |js::GetProxyReservedSlot| in "js/Proxy.h" is very slightly more efficient. + */ +inline const Value& GetReservedSlot(JSObject* obj, size_t slot) { + MOZ_ASSERT(slot < JSCLASS_RESERVED_SLOTS(GetClass(obj))); + return reinterpret_cast(obj)->slotRef(slot); +} + +namespace detail { + +extern JS_PUBLIC_API void SetReservedSlotWithBarrier(JSObject* obj, size_t slot, + const Value& value); + +} // namespace detail + +/** + * Store a value in an object's reserved slot. + * + * This can be used with both native objects and proxies. However, if |obj| is + * known to be a proxy, |js::SetProxyReservedSlot| in "js/Proxy.h" is very + * slightly more efficient. + */ +inline void SetReservedSlot(JSObject* obj, size_t slot, const Value& value) { + MOZ_ASSERT(slot < JSCLASS_RESERVED_SLOTS(GetClass(obj))); + auto* sobj = reinterpret_cast(obj); + if (sobj->slotRef(slot).isGCThing() || value.isGCThing()) { + detail::SetReservedSlotWithBarrier(obj, slot, value); + } else { + sobj->slotRef(slot) = value; + } +} + +/** + * Helper function to get the pointer value (or nullptr if not set) from an + * object's reserved slot. The slot must contain either a PrivateValue(T*) or + * UndefinedValue. + */ +template +inline T* GetMaybePtrFromReservedSlot(JSObject* obj, size_t slot) { + Value v = GetReservedSlot(obj, slot); + return v.isUndefined() ? nullptr : static_cast(v.toPrivate()); +} + +/** + * Helper function to get the pointer value (or nullptr if not set) from the + * object's first reserved slot. Must only be used for objects with a JSClass + * that has the JSCLASS_SLOT0_IS_NSISUPPORTS flag. + */ +template +inline T* GetObjectISupports(JSObject* obj) { + MOZ_ASSERT(GetClass(obj)->slot0IsISupports()); + return GetMaybePtrFromReservedSlot(obj, 0); +} + +/** + * Helper function to store |PrivateValue(nsISupportsValue)| in the object's + * first reserved slot. Must only be used for objects with a JSClass that has + * the JSCLASS_SLOT0_IS_NSISUPPORTS flag. + * + * Note: the pointer is opaque to the JS engine (including the GC) so it's the + * embedding's responsibility to trace or free this value. + */ +inline void SetObjectISupports(JSObject* obj, void* nsISupportsValue) { + MOZ_ASSERT(GetClass(obj)->slot0IsISupports()); + SetReservedSlot(obj, 0, PrivateValue(nsISupportsValue)); +} + +} // namespace JS + +// JSObject* is an aligned pointer, but this information isn't available in the +// public header. We specialize HasFreeLSB here so that JS::Result +// compiles. + +namespace mozilla { +namespace detail { +template <> +struct HasFreeLSB { + static constexpr bool value = true; +}; +} // namespace detail +} // namespace mozilla + +#endif // js_public_Object_h -- cgit v1.2.3