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+/* -*- 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 GCHashTable_h
+#define GCHashTable_h
+
+#include "js/GCPolicyAPI.h"
+#include "js/HashTable.h"
+#include "js/RootingAPI.h"
+#include "js/SweepingAPI.h"
+#include "js/TracingAPI.h"
+
+namespace JS {
+
+// Define a reasonable default GC policy for GC-aware Maps.
+template <typename Key, typename Value>
+struct DefaultMapSweepPolicy {
+ static bool needsSweep(Key* key, Value* value) {
+ return GCPolicy<Key>::needsSweep(key) || GCPolicy<Value>::needsSweep(value);
+ }
+};
+
+// A GCHashMap is a GC-aware HashMap, meaning that it has additional trace and
+// sweep methods that know how to visit all keys and values in the table.
+// HashMaps that contain GC pointers will generally want to use this GCHashMap
+// specialization instead of HashMap, because this conveniently supports tracing
+// keys and values, and cleaning up weak entries.
+//
+// GCHashMap::trace applies GCPolicy<T>::trace to each entry's key and value.
+// Most types of GC pointers already have appropriate specializations of
+// GCPolicy, so they should just work as keys and values. Any struct type with a
+// default constructor and trace and sweep functions should work as well. If you
+// need to define your own GCPolicy specialization, generic helpers can be found
+// in js/public/TracingAPI.h.
+//
+// The MapSweepPolicy template parameter controls how the table drops entries
+// when swept. GCHashMap::sweep applies MapSweepPolicy::needsSweep to each table
+// entry; if it returns true, the entry is dropped. The default MapSweepPolicy
+// drops the entry if either the key or value is about to be finalized,
+// according to its GCPolicy<T>::needsSweep method. (This default is almost
+// always fine: it's hard to imagine keeping such an entry around anyway.)
+//
+// Note that this HashMap only knows *how* to trace and sweep, but it does not
+// itself cause tracing or sweeping to be invoked. For tracing, it must be used
+// with Rooted or PersistentRooted, or barriered and traced manually. For
+// sweeping, currently it requires an explicit call to <map>.sweep().
+template <typename Key,
+ typename Value,
+ typename HashPolicy = js::DefaultHasher<Key>,
+ typename AllocPolicy = js::TempAllocPolicy,
+ typename MapSweepPolicy = DefaultMapSweepPolicy<Key, Value>>
+class GCHashMap : public js::HashMap<Key, Value, HashPolicy, AllocPolicy>
+{
+ using Base = js::HashMap<Key, Value, HashPolicy, AllocPolicy>;
+
+ public:
+ explicit GCHashMap(AllocPolicy a = AllocPolicy()) : Base(a) {}
+
+ static void trace(GCHashMap* map, JSTracer* trc) { map->trace(trc); }
+ void trace(JSTracer* trc) {
+ if (!this->initialized())
+ return;
+ for (typename Base::Enum e(*this); !e.empty(); e.popFront()) {
+ GCPolicy<Value>::trace(trc, &e.front().value(), "hashmap value");
+ GCPolicy<Key>::trace(trc, &e.front().mutableKey(), "hashmap key");
+ }
+ }
+
+ void sweep() {
+ if (!this->initialized())
+ return;
+
+ for (typename Base::Enum e(*this); !e.empty(); e.popFront()) {
+ if (MapSweepPolicy::needsSweep(&e.front().mutableKey(), &e.front().value()))
+ e.removeFront();
+ }
+ }
+
+ // GCHashMap is movable
+ GCHashMap(GCHashMap&& rhs) : Base(mozilla::Move(rhs)) {}
+ void operator=(GCHashMap&& rhs) {
+ MOZ_ASSERT(this != &rhs, "self-move assignment is prohibited");
+ Base::operator=(mozilla::Move(rhs));
+ }
+
+ private:
+ // GCHashMap is not copyable or assignable
+ GCHashMap(const GCHashMap& hm) = delete;
+ GCHashMap& operator=(const GCHashMap& hm) = delete;
+};
+
+} // namespace JS
+
+namespace js {
+
+// HashMap that supports rekeying.
+//
+// If your keys are pointers to something like JSObject that can be tenured or
+// compacted, prefer to use GCHashMap with MovableCellHasher, which takes
+// advantage of the Zone's stable id table to make rekeying unnecessary.
+template <typename Key,
+ typename Value,
+ typename HashPolicy = DefaultHasher<Key>,
+ typename AllocPolicy = TempAllocPolicy,
+ typename MapSweepPolicy = JS::DefaultMapSweepPolicy<Key, Value>>
+class GCRekeyableHashMap : public JS::GCHashMap<Key, Value, HashPolicy, AllocPolicy, MapSweepPolicy>
+{
+ using Base = JS::GCHashMap<Key, Value, HashPolicy, AllocPolicy>;
+
+ public:
+ explicit GCRekeyableHashMap(AllocPolicy a = AllocPolicy()) : Base(a) {}
+
+ void sweep() {
+ if (!this->initialized())
+ return;
+
+ for (typename Base::Enum e(*this); !e.empty(); e.popFront()) {
+ Key key(e.front().key());
+ if (MapSweepPolicy::needsSweep(&key, &e.front().value()))
+ e.removeFront();
+ else if (!HashPolicy::match(key, e.front().key()))
+ e.rekeyFront(key);
+ }
+ }
+
+ // GCRekeyableHashMap is movable
+ GCRekeyableHashMap(GCRekeyableHashMap&& rhs) : Base(mozilla::Move(rhs)) {}
+ void operator=(GCRekeyableHashMap&& rhs) {
+ MOZ_ASSERT(this != &rhs, "self-move assignment is prohibited");
+ Base::operator=(mozilla::Move(rhs));
+ }
+};
+
+template <typename Outer, typename... Args>
+class GCHashMapOperations
+{
+ using Map = JS::GCHashMap<Args...>;
+ using Lookup = typename Map::Lookup;
+
+ const Map& map() const { return static_cast<const Outer*>(this)->get(); }
+
+ public:
+ using AddPtr = typename Map::AddPtr;
+ using Ptr = typename Map::Ptr;
+ using Range = typename Map::Range;
+
+ bool initialized() const { return map().initialized(); }
+ Ptr lookup(const Lookup& l) const { return map().lookup(l); }
+ AddPtr lookupForAdd(const Lookup& l) const { return map().lookupForAdd(l); }
+ Range all() const { return map().all(); }
+ bool empty() const { return map().empty(); }
+ uint32_t count() const { return map().count(); }
+ size_t capacity() const { return map().capacity(); }
+ bool has(const Lookup& l) const { return map().lookup(l).found(); }
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return map().sizeOfExcludingThis(mallocSizeOf);
+ }
+ size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return mallocSizeOf(this) + map().sizeOfExcludingThis(mallocSizeOf);
+ }
+};
+
+template <typename Outer, typename... Args>
+class MutableGCHashMapOperations
+ : public GCHashMapOperations<Outer, Args...>
+{
+ using Map = JS::GCHashMap<Args...>;
+ using Lookup = typename Map::Lookup;
+
+ Map& map() { return static_cast<Outer*>(this)->get(); }
+
+ public:
+ using AddPtr = typename Map::AddPtr;
+ struct Enum : public Map::Enum { explicit Enum(Outer& o) : Map::Enum(o.map()) {} };
+ using Ptr = typename Map::Ptr;
+ using Range = typename Map::Range;
+
+ bool init(uint32_t len = 16) { return map().init(len); }
+ void clear() { map().clear(); }
+ void finish() { map().finish(); }
+ void remove(Ptr p) { map().remove(p); }
+
+ template<typename KeyInput, typename ValueInput>
+ bool add(AddPtr& p, KeyInput&& k, ValueInput&& v) {
+ return map().add(p, mozilla::Forward<KeyInput>(k), mozilla::Forward<ValueInput>(v));
+ }
+
+ template<typename KeyInput>
+ bool add(AddPtr& p, KeyInput&& k) {
+ return map().add(p, mozilla::Forward<KeyInput>(k), Map::Value());
+ }
+
+ template<typename KeyInput, typename ValueInput>
+ bool relookupOrAdd(AddPtr& p, KeyInput&& k, ValueInput&& v) {
+ return map().relookupOrAdd(p, k,
+ mozilla::Forward<KeyInput>(k),
+ mozilla::Forward<ValueInput>(v));
+ }
+
+ template<typename KeyInput, typename ValueInput>
+ bool put(KeyInput&& k, ValueInput&& v) {
+ return map().put(mozilla::Forward<KeyInput>(k), mozilla::Forward<ValueInput>(v));
+ }
+
+ template<typename KeyInput, typename ValueInput>
+ bool putNew(KeyInput&& k, ValueInput&& v) {
+ return map().putNew(mozilla::Forward<KeyInput>(k), mozilla::Forward<ValueInput>(v));
+ }
+};
+
+template <typename A, typename B, typename C, typename D, typename E>
+class RootedBase<JS::GCHashMap<A,B,C,D,E>>
+ : public MutableGCHashMapOperations<JS::Rooted<JS::GCHashMap<A,B,C,D,E>>, A,B,C,D,E>
+{};
+
+template <typename A, typename B, typename C, typename D, typename E>
+class MutableHandleBase<JS::GCHashMap<A,B,C,D,E>>
+ : public MutableGCHashMapOperations<JS::MutableHandle<JS::GCHashMap<A,B,C,D,E>>, A,B,C,D,E>
+{};
+
+template <typename A, typename B, typename C, typename D, typename E>
+class HandleBase<JS::GCHashMap<A,B,C,D,E>>
+ : public GCHashMapOperations<JS::Handle<JS::GCHashMap<A,B,C,D,E>>, A,B,C,D,E>
+{};
+
+template <typename A, typename B, typename C, typename D, typename E>
+class WeakCacheBase<JS::GCHashMap<A,B,C,D,E>>
+ : public MutableGCHashMapOperations<JS::WeakCache<JS::GCHashMap<A,B,C,D,E>>, A,B,C,D,E>
+{};
+
+} // namespace js
+
+namespace JS {
+
+// A GCHashSet is a HashSet with an additional trace method that knows
+// be traced to be kept alive will generally want to use this GCHashSet
+// specialization in lieu of HashSet.
+//
+// Most types of GC pointers can be traced with no extra infrastructure. For
+// structs and non-gc-pointer members, ensure that there is a specialization of
+// GCPolicy<T> with an appropriate trace method available to handle the custom
+// type. Generic helpers can be found in js/public/TracingAPI.h.
+//
+// Note that although this HashSet's trace will deal correctly with moved
+// elements, it does not itself know when to barrier or trace elements. To
+// function properly it must either be used with Rooted or barriered and traced
+// manually.
+template <typename T,
+ typename HashPolicy = js::DefaultHasher<T>,
+ typename AllocPolicy = js::TempAllocPolicy>
+class GCHashSet : public js::HashSet<T, HashPolicy, AllocPolicy>
+{
+ using Base = js::HashSet<T, HashPolicy, AllocPolicy>;
+
+ public:
+ explicit GCHashSet(AllocPolicy a = AllocPolicy()) : Base(a) {}
+
+ static void trace(GCHashSet* set, JSTracer* trc) { set->trace(trc); }
+ void trace(JSTracer* trc) {
+ if (!this->initialized())
+ return;
+ for (typename Base::Enum e(*this); !e.empty(); e.popFront())
+ GCPolicy<T>::trace(trc, &e.mutableFront(), "hashset element");
+ }
+
+ void sweep() {
+ if (!this->initialized())
+ return;
+ for (typename Base::Enum e(*this); !e.empty(); e.popFront()) {
+ if (GCPolicy<T>::needsSweep(&e.mutableFront()))
+ e.removeFront();
+ }
+ }
+
+ // GCHashSet is movable
+ GCHashSet(GCHashSet&& rhs) : Base(mozilla::Move(rhs)) {}
+ void operator=(GCHashSet&& rhs) {
+ MOZ_ASSERT(this != &rhs, "self-move assignment is prohibited");
+ Base::operator=(mozilla::Move(rhs));
+ }
+
+ private:
+ // GCHashSet is not copyable or assignable
+ GCHashSet(const GCHashSet& hs) = delete;
+ GCHashSet& operator=(const GCHashSet& hs) = delete;
+};
+
+} // namespace JS
+
+namespace js {
+
+template <typename Outer, typename... Args>
+class GCHashSetOperations
+{
+ using Set = JS::GCHashSet<Args...>;
+ using Lookup = typename Set::Lookup;
+
+ const Set& set() const { return static_cast<const Outer*>(this)->get(); }
+
+ public:
+ using AddPtr = typename Set::AddPtr;
+ using Entry = typename Set::Entry;
+ using Ptr = typename Set::Ptr;
+ using Range = typename Set::Range;
+
+ bool initialized() const { return set().initialized(); }
+ Ptr lookup(const Lookup& l) const { return set().lookup(l); }
+ AddPtr lookupForAdd(const Lookup& l) const { return set().lookupForAdd(l); }
+ Range all() const { return set().all(); }
+ bool empty() const { return set().empty(); }
+ uint32_t count() const { return set().count(); }
+ size_t capacity() const { return set().capacity(); }
+ bool has(const Lookup& l) const { return set().lookup(l).found(); }
+ size_t sizeOfExcludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return set().sizeOfExcludingThis(mallocSizeOf);
+ }
+ size_t sizeOfIncludingThis(mozilla::MallocSizeOf mallocSizeOf) const {
+ return mallocSizeOf(this) + set().sizeOfExcludingThis(mallocSizeOf);
+ }
+};
+
+template <typename Outer, typename... Args>
+class MutableGCHashSetOperations
+ : public GCHashSetOperations<Outer, Args...>
+{
+ using Set = JS::GCHashSet<Args...>;
+ using Lookup = typename Set::Lookup;
+
+ Set& set() { return static_cast<Outer*>(this)->get(); }
+
+ public:
+ using AddPtr = typename Set::AddPtr;
+ using Entry = typename Set::Entry;
+ struct Enum : public Set::Enum { explicit Enum(Outer& o) : Set::Enum(o.set()) {} };
+ using Ptr = typename Set::Ptr;
+ using Range = typename Set::Range;
+
+ bool init(uint32_t len = 16) { return set().init(len); }
+ void clear() { set().clear(); }
+ void finish() { set().finish(); }
+ void remove(Ptr p) { set().remove(p); }
+ void remove(const Lookup& l) { set().remove(l); }
+
+ template<typename TInput>
+ bool add(AddPtr& p, TInput&& t) {
+ return set().add(p, mozilla::Forward<TInput>(t));
+ }
+
+ template<typename TInput>
+ bool relookupOrAdd(AddPtr& p, const Lookup& l, TInput&& t) {
+ return set().relookupOrAdd(p, l, mozilla::Forward<TInput>(t));
+ }
+
+ template<typename TInput>
+ bool put(TInput&& t) {
+ return set().put(mozilla::Forward<TInput>(t));
+ }
+
+ template<typename TInput>
+ bool putNew(TInput&& t) {
+ return set().putNew(mozilla::Forward<TInput>(t));
+ }
+
+ template<typename TInput>
+ bool putNew(const Lookup& l, TInput&& t) {
+ return set().putNew(l, mozilla::Forward<TInput>(t));
+ }
+};
+
+template <typename T, typename HP, typename AP>
+class RootedBase<JS::GCHashSet<T, HP, AP>>
+ : public MutableGCHashSetOperations<JS::Rooted<JS::GCHashSet<T, HP, AP>>, T, HP, AP>
+{
+};
+
+template <typename T, typename HP, typename AP>
+class MutableHandleBase<JS::GCHashSet<T, HP, AP>>
+ : public MutableGCHashSetOperations<JS::MutableHandle<JS::GCHashSet<T, HP, AP>>, T, HP, AP>
+{
+};
+
+template <typename T, typename HP, typename AP>
+class HandleBase<JS::GCHashSet<T, HP, AP>>
+ : public GCHashSetOperations<JS::Handle<JS::GCHashSet<T, HP, AP>>, T, HP, AP>
+{
+};
+
+template <typename T, typename HP, typename AP>
+class WeakCacheBase<JS::GCHashSet<T, HP, AP>>
+ : public MutableGCHashSetOperations<JS::WeakCache<JS::GCHashSet<T, HP, AP>>, T, HP, AP>
+{
+};
+
+} /* namespace js */
+
+#endif /* GCHashTable_h */