gecko-dev/xpcom/glue/nsBaseHashtable.h
Nicholas Nethercote 6c4f582c73 Bug 1168027 - Use PLDHashTable2 in nsTHashtable. r=froydnj.
The added static_casts will be removed when PLDHashTable and PLDHashTable2 are
merged.

--HG--
extra : rebase_source : 49dacef8a86adc088610449b6bd2ef9345af5a84
2015-05-12 17:33:49 -07:00

427 lines
14 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 nsBaseHashtable_h__
#define nsBaseHashtable_h__
#include "mozilla/MemoryReporting.h"
#include "mozilla/Move.h"
#include "nsTHashtable.h"
#include "prlock.h"
#include "nsDebug.h"
template<class KeyClass, class DataType, class UserDataType>
class nsBaseHashtable; // forward declaration
/**
* the private nsTHashtable::EntryType class used by nsBaseHashtable
* @see nsTHashtable for the specification of this class
* @see nsBaseHashtable for template parameters
*/
template<class KeyClass, class DataType>
class nsBaseHashtableET : public KeyClass
{
public:
DataType mData;
friend class nsTHashtable<nsBaseHashtableET<KeyClass, DataType>>;
private:
typedef typename KeyClass::KeyType KeyType;
typedef typename KeyClass::KeyTypePointer KeyTypePointer;
explicit nsBaseHashtableET(KeyTypePointer aKey);
nsBaseHashtableET(nsBaseHashtableET<KeyClass, DataType>&& aToMove);
~nsBaseHashtableET();
};
/**
* templated hashtable for simple data types
* This class manages simple data types that do not need construction or
* destruction.
*
* @param KeyClass a wrapper-class for the hashtable key, see nsHashKeys.h
* for a complete specification.
* @param DataType the datatype stored in the hashtable,
* for example, uint32_t or nsCOMPtr. If UserDataType is not the same,
* DataType must implicitly cast to UserDataType
* @param UserDataType the user sees, for example uint32_t or nsISupports*
*/
template<class KeyClass, class DataType, class UserDataType>
class nsBaseHashtable
: protected nsTHashtable<nsBaseHashtableET<KeyClass, DataType>>
{
typedef mozilla::fallible_t fallible_t;
public:
typedef typename KeyClass::KeyType KeyType;
typedef nsBaseHashtableET<KeyClass, DataType> EntryType;
using nsTHashtable<EntryType>::Contains;
nsBaseHashtable() {}
explicit nsBaseHashtable(uint32_t aInitLength)
: nsTHashtable<EntryType>(aInitLength)
{
}
/**
* Return the number of entries in the table.
* @return number of entries
*/
uint32_t Count() const { return nsTHashtable<EntryType>::Count(); }
/**
* retrieve the value for a key.
* @param aKey the key to retreive
* @param aData data associated with this key will be placed at this
* pointer. If you only need to check if the key exists, aData
* may be null.
* @return true if the key exists. If key does not exist, aData is not
* modified.
*/
bool Get(KeyType aKey, UserDataType* aData) const
{
EntryType* ent = this->GetEntry(aKey);
if (!ent) {
return false;
}
if (aData) {
*aData = ent->mData;
}
return true;
}
/**
* For pointer types, get the value, returning nullptr if the entry is not
* present in the table.
*
* @param aKey the key to retrieve
* @return The found value, or nullptr if no entry was found with the given key.
* @note If nullptr values are stored in the table, it is not possible to
* distinguish between a nullptr value and a missing entry.
*/
UserDataType Get(KeyType aKey) const
{
EntryType* ent = this->GetEntry(aKey);
if (!ent) {
return 0;
}
return ent->mData;
}
/**
* put a new value for the associated key
* @param aKey the key to put
* @param aData the new data
* @return always true, unless memory allocation failed
*/
void Put(KeyType aKey, const UserDataType& aData)
{
if (!Put(aKey, aData, mozilla::fallible)) {
NS_ABORT_OOM(this->mTable.EntrySize() * this->mTable.EntryCount());
}
}
MOZ_WARN_UNUSED_RESULT bool Put(KeyType aKey, const UserDataType& aData,
const fallible_t&)
{
EntryType* ent = this->PutEntry(aKey);
if (!ent) {
return false;
}
ent->mData = aData;
return true;
}
/**
* remove the data for the associated key
* @param aKey the key to remove from the hashtable
*/
void Remove(KeyType aKey) { this->RemoveEntry(aKey); }
/**
* function type provided by the application for enumeration.
* @param aKey the key being enumerated
* @param aData data being enumerated
* @param aUserArg passed unchanged from Enumerate
* @return either
* @link PLDHashOperator::PL_DHASH_NEXT PL_DHASH_NEXT @endlink or
* @link PLDHashOperator::PL_DHASH_STOP PL_DHASH_STOP @endlink
*/
typedef PLDHashOperator (*EnumReadFunction)(KeyType aKey,
UserDataType aData,
void* aUserArg);
/**
* enumerate entries in the hashtable, without allowing changes
* @param aEnumFunc enumeration callback
* @param aUserArg passed unchanged to the EnumReadFunction
*/
uint32_t EnumerateRead(EnumReadFunction aEnumFunc, void* aUserArg) const
{
NS_ASSERTION(this->mTable.IsInitialized(),
"nsBaseHashtable was not initialized properly.");
s_EnumReadArgs enumData = { aEnumFunc, aUserArg };
return PL_DHashTableEnumerate(const_cast<PLDHashTable*>(static_cast<const PLDHashTable*>(&this->mTable)),
s_EnumReadStub,
&enumData);
}
/**
* function type provided by the application for enumeration.
* @param aKey the key being enumerated
* @param aData Reference to data being enumerated, may be altered. e.g. for
* nsInterfaceHashtable this is an nsCOMPtr reference...
* @parm aUserArg passed unchanged from Enumerate
* @return bitflag combination of
* @link PLDHashOperator::PL_DHASH_REMOVE @endlink,
* @link PLDHashOperator::PL_DHASH_NEXT PL_DHASH_NEXT @endlink, or
* @link PLDHashOperator::PL_DHASH_STOP PL_DHASH_STOP @endlink
*/
typedef PLDHashOperator (*EnumFunction)(KeyType aKey,
DataType& aData,
void* aUserArg);
/**
* enumerate entries in the hashtable, allowing changes. This
* functions write-locks the hashtable.
* @param aEnumFunc enumeration callback
* @param aUserArg passed unchanged to the EnumFunction
*/
uint32_t Enumerate(EnumFunction aEnumFunc, void* aUserArg)
{
NS_ASSERTION(this->mTable.IsInitialized(),
"nsBaseHashtable was not initialized properly.");
s_EnumArgs enumData = { aEnumFunc, aUserArg };
return PL_DHashTableEnumerate(&this->mTable,
s_EnumStub,
&enumData);
}
/**
* reset the hashtable, removing all entries
*/
void Clear() { nsTHashtable<EntryType>::Clear(); }
/**
* client must provide a SizeOfEntryExcludingThisFun function for
* SizeOfExcludingThis.
* @param aKey the key being enumerated
* @param aData Reference to data being enumerated.
* @param aMallocSizeOf the function used to measure heap-allocated blocks
* @param aUserArg passed unchanged from SizeOf{In,Ex}cludingThis
* @return summed size of the things pointed to by the entries
*/
typedef size_t
(*SizeOfEntryExcludingThisFun)(KeyType aKey,
const DataType& aData,
mozilla::MallocSizeOf aMallocSizeOf,
void* aUserArg);
/**
* Measure the size of the table's entry storage and the table itself.
* If |aSizeOfEntryExcludingThis| is non-nullptr, measure the size of things
* pointed to by entries.
*
* @param aSizeOfEntryExcludingThis
* the <code>SizeOfEntryExcludingThisFun</code> function to call
* @param aMallocSizeOf the function used to meeasure heap-allocated blocks
* @param aUserArg a point to pass to the
* <code>SizeOfEntryExcludingThisFun</code> function
* @return the summed size of the entries, the table, and the table's storage
*/
size_t SizeOfIncludingThis(SizeOfEntryExcludingThisFun aSizeOfEntryExcludingThis,
mozilla::MallocSizeOf aMallocSizeOf,
void* aUserArg = nullptr)
{
return aMallocSizeOf(this) +
this->SizeOfExcludingThis(aSizeOfEntryExcludingThis, aMallocSizeOf,
aUserArg);
}
/**
* Measure the size of the table's entry storage, and if
* |aSizeOfEntryExcludingThis| is non-nullptr, measure the size of things
* pointed to by entries.
*
* @param aSizeOfEntryExcludingThis the
* <code>SizeOfEntryExcludingThisFun</code> function to call
* @param aMallocSizeOf the function used to measure heap-allocated blocks
* @param aUserArg a pointer to pass to the
* <code>SizeOfEntryExcludingThisFun</code> function
* @return the summed size of all the entries
*/
size_t SizeOfExcludingThis(SizeOfEntryExcludingThisFun aSizeOfEntryExcludingThis,
mozilla::MallocSizeOf aMallocSizeOf,
void* aUserArg = nullptr) const
{
if (aSizeOfEntryExcludingThis) {
s_SizeOfArgs args = { aSizeOfEntryExcludingThis, aUserArg };
return PL_DHashTableSizeOfExcludingThis(&this->mTable, s_SizeOfStub,
aMallocSizeOf, &args);
}
return PL_DHashTableSizeOfExcludingThis(&this->mTable, nullptr,
aMallocSizeOf);
}
#ifdef DEBUG
using nsTHashtable<EntryType>::MarkImmutable;
#endif
protected:
/**
* used internally during EnumerateRead. Allocated on the stack.
* @param func the enumerator passed to EnumerateRead
* @param userArg the userArg passed to EnumerateRead
*/
struct s_EnumReadArgs
{
EnumReadFunction func;
void* userArg;
};
static PLDHashOperator s_EnumReadStub(PLDHashTable* aTable,
PLDHashEntryHdr* aHdr,
uint32_t aNumber,
void* aArg);
struct s_EnumArgs
{
EnumFunction func;
void* userArg;
};
static PLDHashOperator s_EnumStub(PLDHashTable* aTable,
PLDHashEntryHdr* aHdr,
uint32_t aNumber,
void* aArg);
struct s_SizeOfArgs
{
SizeOfEntryExcludingThisFun func;
void* userArg;
};
static size_t s_SizeOfStub(PLDHashEntryHdr* aEntry,
mozilla::MallocSizeOf aMallocSizeOf,
void* aArg);
};
class nsCycleCollectionTraversalCallback;
struct MOZ_STACK_CLASS nsBaseHashtableCCTraversalData
{
nsBaseHashtableCCTraversalData(nsCycleCollectionTraversalCallback& aCallback,
const char* aName,
uint32_t aFlags)
: mCallback(aCallback)
, mName(aName)
, mFlags(aFlags)
{
}
nsCycleCollectionTraversalCallback& mCallback;
const char* mName;
uint32_t mFlags;
};
template<typename K, typename T>
PLDHashOperator
ImplCycleCollectionTraverse_EnumFunc(K aKey,
T aData,
void* aUserData)
{
nsBaseHashtableCCTraversalData* userData =
static_cast<nsBaseHashtableCCTraversalData*>(aUserData);
CycleCollectionNoteChild(userData->mCallback,
aData,
userData->mName,
userData->mFlags);
return PL_DHASH_NEXT;
}
//
// nsBaseHashtableET definitions
//
template<class KeyClass, class DataType>
nsBaseHashtableET<KeyClass, DataType>::nsBaseHashtableET(KeyTypePointer aKey)
: KeyClass(aKey)
, mData()
{
}
template<class KeyClass, class DataType>
nsBaseHashtableET<KeyClass, DataType>::nsBaseHashtableET(
nsBaseHashtableET<KeyClass, DataType>&& aToMove)
: KeyClass(mozilla::Move(aToMove))
, mData(mozilla::Move(aToMove.mData))
{
}
template<class KeyClass, class DataType>
nsBaseHashtableET<KeyClass, DataType>::~nsBaseHashtableET()
{
}
//
// nsBaseHashtable definitions
//
template<class KeyClass, class DataType, class UserDataType>
PLDHashOperator
nsBaseHashtable<KeyClass, DataType, UserDataType>::s_EnumReadStub(
PLDHashTable* aTable, PLDHashEntryHdr* aHdr, uint32_t aNumber, void* aArg)
{
EntryType* ent = static_cast<EntryType*>(aHdr);
s_EnumReadArgs* eargs = (s_EnumReadArgs*)aArg;
PLDHashOperator res = (eargs->func)(ent->GetKey(), ent->mData, eargs->userArg);
NS_ASSERTION(!(res & PL_DHASH_REMOVE),
"PL_DHASH_REMOVE return during const enumeration; ignoring.");
if (res & PL_DHASH_STOP) {
return PL_DHASH_STOP;
}
return PL_DHASH_NEXT;
}
template<class KeyClass, class DataType, class UserDataType>
PLDHashOperator
nsBaseHashtable<KeyClass, DataType, UserDataType>::s_EnumStub(
PLDHashTable* aTable, PLDHashEntryHdr* aHdr, uint32_t aNumber, void* aArg)
{
EntryType* ent = static_cast<EntryType*>(aHdr);
s_EnumArgs* eargs = (s_EnumArgs*)aArg;
return (eargs->func)(ent->GetKey(), ent->mData, eargs->userArg);
}
template<class KeyClass, class DataType, class UserDataType>
size_t
nsBaseHashtable<KeyClass, DataType, UserDataType>::s_SizeOfStub(
PLDHashEntryHdr* aHdr, mozilla::MallocSizeOf aMallocSizeOf, void* aArg)
{
EntryType* ent = static_cast<EntryType*>(aHdr);
s_SizeOfArgs* eargs = static_cast<s_SizeOfArgs*>(aArg);
return (eargs->func)(ent->GetKey(), ent->mData, aMallocSizeOf, eargs->userArg);
}
#endif // nsBaseHashtable_h__