tor-browser

The Tor Browser
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ObjectFlags-inl.h (3321B)

      1 /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*-
      2 * vim: set ts=8 sts=2 et sw=2 tw=80:
      3 * This Source Code Form is subject to the terms of the Mozilla Public
      4 * License, v. 2.0. If a copy of the MPL was not distributed with this
      5 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
      6 
      7 #ifndef vm_ObjectFlags_inl_h
      8 #define vm_ObjectFlags_inl_h
      9 
     10 #include "vm/ObjectFlags.h"
     11 
     12 #include "builtin/Array.h"
     13 #include "vm/JSAtomState.h"
     14 #include "vm/JSContext.h"
     15 #include "vm/PlainObject.h"
     16 #include "vm/PropertyInfo.h"
     17 
     18 namespace js {
     19 
     20 MOZ_ALWAYS_INLINE ObjectFlags
     21 GetObjectFlagsForNewProperty(const JSClass* clasp, ObjectFlags flags, jsid id,
     22                             PropertyFlags propFlags, JSContext* cx) {
     23  uint32_t index;
     24  if (IdIsIndex(id, &index)) {
     25    flags.setFlag(ObjectFlag::Indexed);
     26  } else if (id.isSymbol() && id.toSymbol()->isInterestingSymbol()) {
     27    flags.setFlag(ObjectFlag::HasInterestingSymbol);
     28  }
     29 
     30  if ((!propFlags.isDataProperty() || !propFlags.writable()) &&
     31      clasp == &PlainObject::class_ && !id.isAtom(cx->names().proto_)) {
     32    flags.setFlag(ObjectFlag::HasNonWritableOrAccessorPropExclProto);
     33  }
     34 
     35  // https://tc39.es/ecma262/multipage/ordinary-and-exotic-objects-behaviours.html#sec-proxy-object-internal-methods-and-internal-slots-get-p-receiver
     36  // Proxy.[[Get]] or [[Set]] Step 9
     37  if (!propFlags.configurable()) {
     38    MOZ_ASSERT(clasp->isNativeObject());
     39    // NOTE: there is a hole which this flag does not cover, which is if the
     40    // class has a resolve hook which could lazily define a non-configurable
     41    // non-writable property. We can just look this up directly though in the
     42    // JIT.
     43    if (propFlags.isDataProperty() && !propFlags.writable()) {
     44      flags.setFlag(ObjectFlag::NeedsProxyGetSetResultValidation);
     45    } else if (propFlags.isAccessorProperty()) {
     46      // This will cover us for both get trap validation and set trap
     47      // validation. We could be more aggressive, because what we really
     48      // care about is if there is a getter but not a setter and vice
     49      // versa, but the first pass at doing that resulted in test
     50      // failures. We'll need to work on that as a follow-up if it is
     51      // important.
     52      flags.setFlag(ObjectFlag::NeedsProxyGetSetResultValidation);
     53    }
     54  }
     55 
     56  if (propFlags.enumerable()) {
     57    flags.setFlag(ObjectFlag::HasEnumerable);
     58  }
     59 
     60  return flags;
     61 }
     62 
     63 // When reusing another shape's PropMap, we need to copy the object flags that
     64 // are based on property information. This is equivalent to (but faster than)
     65 // calling GetObjectFlagsForNewProperty for all properties in the map.
     66 inline ObjectFlags CopyPropMapObjectFlags(ObjectFlags dest,
     67                                          ObjectFlags source) {
     68  if (source.hasFlag(ObjectFlag::Indexed)) {
     69    dest.setFlag(ObjectFlag::Indexed);
     70  }
     71  if (source.hasFlag(ObjectFlag::HasInterestingSymbol)) {
     72    dest.setFlag(ObjectFlag::HasInterestingSymbol);
     73  }
     74  if (source.hasFlag(ObjectFlag::HasNonWritableOrAccessorPropExclProto)) {
     75    dest.setFlag(ObjectFlag::HasNonWritableOrAccessorPropExclProto);
     76  }
     77  if (source.hasFlag(ObjectFlag::NeedsProxyGetSetResultValidation)) {
     78    dest.setFlag(ObjectFlag::NeedsProxyGetSetResultValidation);
     79  }
     80  return dest;
     81 }
     82 
     83 }  // namespace js
     84 
     85 #endif /* vm_ObjectFlags_inl_h */