michael@0: /* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
michael@0:  * vim: set ts=8 sts=4 et sw=4 tw=99:
michael@0:  * This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: #ifndef jshashutil_h
michael@0: #define jshashutil_h
michael@0: 
michael@0: #include "jscntxt.h"
michael@0: 
michael@0: namespace js {
michael@0: 
michael@0: /*
michael@0:  * Used to add entries to a js::HashMap or HashSet where the key depends on a GC
michael@0:  * thing that may be moved by generational collection between the call to
michael@0:  * lookupForAdd() and relookupOrAdd().
michael@0:  */
michael@0: template <class T>
michael@0: struct DependentAddPtr
michael@0: {
michael@0:     typedef typename T::AddPtr AddPtr;
michael@0:     typedef typename T::Entry Entry;
michael@0: 
michael@0:     template <class Lookup>
michael@0:     DependentAddPtr(const ExclusiveContext *cx, const T &table, const Lookup &lookup)
michael@0:       : addPtr(table.lookupForAdd(lookup))
michael@0: #ifdef JSGC_GENERATIONAL
michael@0:       , originalGcNumber(cx->zone()->gcNumber())
michael@0: #endif
michael@0:         {}
michael@0: 
michael@0:     template <class KeyInput, class ValueInput>
michael@0:     bool add(const ExclusiveContext *cx, T &table, const KeyInput &key, const ValueInput &value) {
michael@0: #ifdef JSGC_GENERATIONAL
michael@0:         bool gcHappened = originalGcNumber != cx->zone()->gcNumber();
michael@0:         if (gcHappened)
michael@0:             addPtr = table.lookupForAdd(key);
michael@0: #endif
michael@0:         return table.relookupOrAdd(addPtr, key, value);
michael@0:     }
michael@0: 
michael@0:     typedef void (DependentAddPtr::* ConvertibleToBool)();
michael@0:     void nonNull() {}
michael@0: 
michael@0:     bool found() const                 { return addPtr.found(); }
michael@0:     operator ConvertibleToBool() const { return found() ? &DependentAddPtr::nonNull : 0; }
michael@0:     const Entry &operator*() const     { return *addPtr; }
michael@0:     const Entry *operator->() const    { return &*addPtr; }
michael@0: 
michael@0:   private:
michael@0:     AddPtr addPtr ;
michael@0: #ifdef JSGC_GENERATIONAL
michael@0:     const uint64_t originalGcNumber;
michael@0: #endif
michael@0: 
michael@0:     DependentAddPtr() MOZ_DELETE;
michael@0:     DependentAddPtr(const DependentAddPtr&) MOZ_DELETE;
michael@0:     DependentAddPtr& operator=(const DependentAddPtr&) MOZ_DELETE;
michael@0: };
michael@0: 
michael@0: } // namespace js
michael@0: 
michael@0: #endif