зеркало из https://github.com/mozilla/gecko-dev.git
81 строка
2.8 KiB
C++
81 строка
2.8 KiB
C++
/* -*- 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 mozilla_recordreplay_ValueIndex_h
|
|
#define mozilla_recordreplay_ValueIndex_h
|
|
|
|
#include "mozilla/Types.h"
|
|
|
|
#include <unordered_map>
|
|
|
|
namespace mozilla {
|
|
namespace recordreplay {
|
|
|
|
// ValueIndexes are a bidirectional map between arbitrary pointers and indexes.
|
|
// These are used while recording and replaying to handle the general issue
|
|
// that pointer values are not preserved during replay: recording a pointer and
|
|
// replaying its bits later will not yield a pointer to the same heap value,
|
|
// but rather a pointer to garbage that must not be dereferenced.
|
|
//
|
|
// When entries are added to a ValueIndex at consistent points between
|
|
// recording and replaying, then the resulting indexes will be consistent, and
|
|
// that index can be recorded and later replayed and used to find the
|
|
// replay-specific pointer value corresponding to the pointer used at that
|
|
// point in the recording. Entries can be removed from the ValueIndex at
|
|
// different points in the recording and replay without affecting the indexes
|
|
// that will be generated later.
|
|
//
|
|
// This is a helper class that is used in various places to help record/replay
|
|
// pointers to heap data.
|
|
class ValueIndex {
|
|
public:
|
|
ValueIndex() : mIndexCount(0) {}
|
|
|
|
typedef std::unordered_map<const void*, size_t> ValueToIndexMap;
|
|
|
|
// Add a new entry to the map.
|
|
size_t Insert(const void* aValue);
|
|
|
|
// Remove an entry from the map, unless there is no entry for aValue.
|
|
void Remove(const void* aValue);
|
|
|
|
// Get the index for an entry in the map. The entry must exist in the map.
|
|
size_t GetIndex(const void* aValue);
|
|
|
|
// Get the index for an entry in the map if there is one, otherwise return
|
|
// false.
|
|
bool MaybeGetIndex(const void* aValue, size_t* aIndex);
|
|
|
|
// Return whether there is an entry for aValue.
|
|
bool Contains(const void* aValue);
|
|
|
|
// Get the value associated with an index. The index must exist in the map.
|
|
const void* GetValue(size_t aIndex);
|
|
|
|
// Whether the map is empty.
|
|
bool IsEmpty();
|
|
|
|
// Raw read-only access to the map contents.
|
|
const ValueToIndexMap& GetValueToIndexMap();
|
|
|
|
private:
|
|
typedef std::unordered_map<size_t, const void*> IndexToValueMap;
|
|
|
|
// Map from pointer values to indexes.
|
|
ValueToIndexMap mValueToIndex;
|
|
|
|
// Map from indexes to pointer values.
|
|
IndexToValueMap mIndexToValue;
|
|
|
|
// The total number of entries that have ever been added to this map.
|
|
size_t mIndexCount;
|
|
};
|
|
|
|
} // namespace recordreplay
|
|
} // namespace mozilla
|
|
|
|
#endif // mozilla_recordreplay_ValueIndex_h
|