js/src/vm/List-inl.h

   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_List_inl_h
   8 #define vm_List_inl_h
   9
  10 #include "vm/List.h"
  11
  12 #include "mozilla/Assertions.h"  // MOZ_ASSERT
  13
  14 #include <stdint.h>  // uint32_t
  15
  16 #include "js/RootingAPI.h"    // JS::Handle, JS::Rooted
  17 #include "js/Value.h"         // JS::Value, JS::ObjectValue
  18 #include "vm/JSContext.h"     // JSContext
  19 #include "vm/NativeObject.h"  // js::NativeObject
  20
  21 #include "vm/Compartment-inl.h"   // JS::Compartment::wrap
  22 #include "vm/JSObject-inl.h"      // js::NewObjectWithGivenProto
  23 #include "vm/NativeObject-inl.h"  // js::NativeObject::*
  24 #include "vm/Realm-inl.h"         // js::AutoRealm
  25
  26 inline /* static */ js::ListObject* js::ListObject::create(JSContext* cx) {
  27   return NewObjectWithGivenProto<ListObject>(cx, nullptr);
  28 }
  29
  30 inline bool js::ListObject::append(JSContext* cx, JS::Handle<JS::Value> value) {
  31   uint32_t len = length();
  32
  33   if (!ensureElements(cx, len + 1)) {
  34     return false;
  35   }
  36
  37   ensureDenseInitializedLength(len, 1);
  38   setDenseElement(len, value);
  39   return true;
  40 }
  41
  42 inline bool js::ListObject::appendValueAndSize(JSContext* cx,
  43                                                JS::Handle<JS::Value> value,
  44                                                double size) {
  45   uint32_t len = length();
  46
  47   if (!ensureElements(cx, len + 2)) {
  48     return false;
  49   }
  50
  51   ensureDenseInitializedLength(len, 2);
  52   setDenseElement(len, value);
  53   setDenseElement(len + 1, JS::DoubleValue(size));
  54   return true;
  55 }
  56
  57 inline JS::Value js::ListObject::popFirst(JSContext* cx) {
  58   uint32_t len = length();
  59   MOZ_ASSERT(len > 0);
  60
  61   JS::Value entry = get(0);
  62   if (!tryShiftDenseElements(1)) {
  63     moveDenseElements(0, 1, len - 1);
  64     setDenseInitializedLength(len - 1);
  65     shrinkElements(cx, len - 1);
  66   }
  67
  68   MOZ_ASSERT(length() == len - 1);
  69   return entry;
  70 }
  71
  72 inline void js::ListObject::popFirstPair(JSContext* cx) {
  73   uint32_t len = length();
  74   MOZ_ASSERT(len > 0);
  75   MOZ_ASSERT((len % 2) == 0);
  76
  77   if (!tryShiftDenseElements(2)) {
  78     moveDenseElements(0, 2, len - 2);
  79     setDenseInitializedLength(len - 2);
  80     shrinkElements(cx, len - 2);
  81   }
  82
  83   MOZ_ASSERT(length() == len - 2);
  84 }
  85
  86 template <class T>
  87 inline T& js::ListObject::popFirstAs(JSContext* cx) {
  88   return popFirst(cx).toObject().as<T>();
  89 }
  90
  91 namespace js {
  92
  93 /**
  94  * Stores an empty ListObject in the given fixed slot of |obj|.
  95  */
  96 [[nodiscard]] inline bool StoreNewListInFixedSlot(JSContext* cx,
  97                                                   JS::Handle<NativeObject*> obj,
  98                                                   uint32_t slot) {
  99   AutoRealm ar(cx, obj);
 100   ListObject* list = ListObject::create(cx);
 101   if (!list) {
 102     return false;
 103   }
 104
 105   obj->setFixedSlot(slot, JS::ObjectValue(*list));
 106   return true;
 107 }
 108
 109 /**
 110  * Given an object |obj| whose fixed slot |slot| contains a ListObject, append
 111  * |toAppend| to that list.
 112  */
 113 [[nodiscard]] inline bool AppendToListInFixedSlot(
 114     JSContext* cx, JS::Handle<NativeObject*> obj, uint32_t slot,
 115     JS::Handle<JSObject*> toAppend) {
 116   JS::Rooted<ListObject*> list(
 117       cx, &obj->getFixedSlot(slot).toObject().as<ListObject>());
 118
 119   AutoRealm ar(cx, list);
 120   JS::Rooted<JS::Value> val(cx, JS::ObjectValue(*toAppend));
 121   if (!cx->compartment()->wrap(cx, &val)) {
 122     return false;
 123   }
 124   return list->append(cx, val);
 125 }
 126
 127 }  // namespace js
 128
 129 #endif  // vm_List_inl_h