gecko-dev/layout/base/nsPresArena.h

164 lines
4.8 KiB
C++

/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: set ts=2 sw=2 et tw=78:
* 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/.
*/
/* arena allocation for the frame tree and closely-related objects */
#ifndef nsPresArena_h___
#define nsPresArena_h___
#include "mozilla/ArenaObjectID.h"
#include "mozilla/ArenaRefPtr.h"
#include "mozilla/MemoryChecking.h" // Note: Do not remove this, needed for MOZ_HAVE_MEM_CHECKS below
#include "mozilla/MemoryReporting.h"
#include <stdint.h>
#include "nscore.h"
#include "nsDataHashtable.h"
#include "nsHashKeys.h"
#include "nsTArray.h"
#include "nsTHashtable.h"
#include "plarena.h"
struct nsArenaMemoryStats;
class nsPresArena {
public:
nsPresArena();
~nsPresArena();
/**
* Pool allocation with recycler lists indexed by object size, aSize.
*/
void* AllocateBySize(size_t aSize)
{
return Allocate(uint32_t(aSize) |
uint32_t(mozilla::eArenaObjectID_NON_OBJECT_MARKER), aSize);
}
void FreeBySize(size_t aSize, void* aPtr)
{
Free(uint32_t(aSize) |
uint32_t(mozilla::eArenaObjectID_NON_OBJECT_MARKER), aPtr);
}
/**
* Pool allocation with recycler lists indexed by frame-type ID.
* Every aID must always be used with the same object size, aSize.
*/
void* AllocateByFrameID(nsQueryFrame::FrameIID aID, size_t aSize)
{
return Allocate(aID, aSize);
}
void FreeByFrameID(nsQueryFrame::FrameIID aID, void* aPtr)
{
Free(aID, aPtr);
}
/**
* Pool allocation with recycler lists indexed by object-type ID (see above).
* Every aID must always be used with the same object size, aSize.
*/
void* AllocateByObjectID(mozilla::ArenaObjectID aID, size_t aSize)
{
return Allocate(aID, aSize);
}
void FreeByObjectID(mozilla::ArenaObjectID aID, void* aPtr)
{
Free(aID, aPtr);
}
/**
* Register an ArenaRefPtr to be cleared when this arena is about to
* be destroyed.
*
* (Defined in ArenaRefPtrInlines.h.)
*
* @param aPtr The ArenaRefPtr to clear.
* @param aObjectID The ArenaObjectID value that uniquely identifies
* the type of object the ArenaRefPtr holds.
*/
template<typename T>
void RegisterArenaRefPtr(mozilla::ArenaRefPtr<T>* aPtr);
/**
* Deregister an ArenaRefPtr that was previously registered with
* RegisterArenaRefPtr.
*/
template<typename T>
void DeregisterArenaRefPtr(mozilla::ArenaRefPtr<T>* aPtr)
{
MOZ_ASSERT(mArenaRefPtrs.Contains(aPtr));
mArenaRefPtrs.Remove(aPtr);
}
/**
* Clears all currently registered ArenaRefPtrs. This will be called during
* the destructor, but can be called by users of nsPresArena who want to
* ensure arena-allocated objects are released earlier.
*/
void ClearArenaRefPtrs();
/**
* Clears all currently registered ArenaRefPtrs for the given ArenaObjectID.
* This is called when we reconstruct the rule tree so that style contexts
* pointing into the old rule tree aren't released afterwards, triggering an
* assertion in ~nsStyleContext.
*/
void ClearArenaRefPtrs(mozilla::ArenaObjectID aObjectID);
/**
* Increment aArenaStats with sizes of interesting objects allocated in this
* arena and its mOther field with the size of everything else.
*/
void AddSizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf,
nsArenaMemoryStats* aArenaStats);
private:
void* Allocate(uint32_t aCode, size_t aSize);
void Free(uint32_t aCode, void* aPtr);
inline void ClearArenaRefPtrWithoutDeregistering(
void* aPtr,
mozilla::ArenaObjectID aObjectID);
// All keys to this hash table fit in 32 bits (see below) so we do not
// bother actually hashing them.
class FreeList : public PLDHashEntryHdr
{
public:
typedef uint32_t KeyType;
nsTArray<void *> mEntries;
size_t mEntrySize;
size_t mEntriesEverAllocated;
typedef const void* KeyTypePointer;
KeyTypePointer mKey;
explicit FreeList(KeyTypePointer aKey)
: mEntrySize(0), mEntriesEverAllocated(0), mKey(aKey) {}
// Default copy constructor and destructor are ok.
bool KeyEquals(KeyTypePointer const aKey) const
{ return mKey == aKey; }
static KeyTypePointer KeyToPointer(KeyType aKey)
{ return NS_INT32_TO_PTR(aKey); }
static PLDHashNumber HashKey(KeyTypePointer aKey)
{ return NS_PTR_TO_INT32(aKey); }
size_t SizeOfExcludingThis(mozilla::MallocSizeOf aMallocSizeOf) const
{ return mEntries.ShallowSizeOfExcludingThis(aMallocSizeOf); }
enum { ALLOW_MEMMOVE = false };
};
nsTHashtable<FreeList> mFreeLists;
PLArenaPool mPool;
nsDataHashtable<nsPtrHashKey<void>, mozilla::ArenaObjectID> mArenaRefPtrs;
};
#endif