gecko-dev/xpcom/ds/nsHashtable.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/*
* The contents of this file are subject to the Netscape Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/NPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is mozilla.org code.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*/
#include "prmem.h"
#include "prlog.h"
#include "nsHashtable.h"
//
// Key operations
//
static PR_CALLBACK PLHashNumber _hashValue(const void *key)
{
return ((const nsHashKey *) key)->HashValue();
}
static PR_CALLBACK PRIntn _hashKeyCompare(const void *key1, const void *key2) {
return ((const nsHashKey *) key1)->Equals((const nsHashKey *) key2);
}
static PR_CALLBACK PRIntn _hashValueCompare(const void *value1,
const void *value2) {
// We're not going to make any assumptions about value equality
return 0;
}
//
// Memory callbacks
//
static PR_CALLBACK void *_hashAllocTable(void *pool, PRSize size) {
return PR_MALLOC(size);
}
static PR_CALLBACK void _hashFreeTable(void *pool, void *item) {
PR_DELETE(item);
}
static PR_CALLBACK PLHashEntry *_hashAllocEntry(void *pool, const void *key) {
return PR_NEW(PLHashEntry);
}
static PR_CALLBACK void _hashFreeEntry(void *pool, PLHashEntry *entry,
PRUintn flag) {
if (flag == HT_FREE_ENTRY) {
delete (nsHashKey *) (entry->key);
PR_DELETE(entry);
}
}
static PLHashAllocOps _hashAllocOps = {
_hashAllocTable, _hashFreeTable,
_hashAllocEntry, _hashFreeEntry
};
//
// Enumerator callback
//
struct _HashEnumerateArgs {
nsHashtableEnumFunc fn;
void* arg;
};
static PR_CALLBACK PRIntn _hashEnumerate(PLHashEntry *he, PRIntn i, void *arg)
{
_HashEnumerateArgs* thunk = (_HashEnumerateArgs*)arg;
return thunk->fn((nsHashKey *) he->key, he->value, thunk->arg)
? HT_ENUMERATE_NEXT
: HT_ENUMERATE_STOP;
}
//
// HashKey
//
nsHashKey::nsHashKey(void)
{
}
nsHashKey::~nsHashKey(void)
{
}
nsHashtable::nsHashtable(PRUint32 aInitSize, PRBool threadSafe)
: mLock(NULL)
{
hashtable = PL_NewHashTable(aInitSize,
_hashValue,
_hashKeyCompare,
_hashValueCompare,
&_hashAllocOps,
NULL);
if (threadSafe == PR_TRUE)
{
mLock = PR_NewLock();
if (mLock == NULL)
{
// Cannot create a lock. If running on a multiprocessing system
// we are sure to die.
PR_ASSERT(mLock != NULL);
}
}
}
nsHashtable::~nsHashtable() {
PL_HashTableDestroy(hashtable);
if (mLock) PR_DestroyLock(mLock);
}
PRBool nsHashtable::Exists(nsHashKey *aKey)
{
PLHashNumber hash = aKey->HashValue();
if (mLock) PR_Lock(mLock);
PLHashEntry **hep = PL_HashTableRawLookup(hashtable, hash, (void *) aKey);
if (mLock) PR_Unlock(mLock);
return *hep != NULL;
}
void *nsHashtable::Put(nsHashKey *aKey, void *aData) {
void *res = NULL;
PLHashNumber hash = aKey->HashValue();
PLHashEntry *he;
if (mLock) PR_Lock(mLock);
PLHashEntry **hep = PL_HashTableRawLookup(hashtable, hash, (void *) aKey);
if ((he = *hep) != NULL) {
res = he->value;
he->value = aData;
} else {
PL_HashTableRawAdd(hashtable, hep, hash,
(void *) aKey->Clone(), aData);
}
if (mLock) PR_Unlock(mLock);
return res;
}
void *nsHashtable::Get(nsHashKey *aKey) {
if (mLock) PR_Lock(mLock);
void *ret = PL_HashTableLookup(hashtable, (void *) aKey);
if (mLock) PR_Unlock(mLock);
return ret;
}
void *nsHashtable::Remove(nsHashKey *aKey) {
PLHashNumber hash = aKey->HashValue();
PLHashEntry *he;
if (mLock) PR_Lock(mLock);
PLHashEntry **hep = PL_HashTableRawLookup(hashtable, hash, (void *) aKey);
void *res = NULL;
if ((he = *hep) != NULL) {
res = he->value;
PL_HashTableRawRemove(hashtable, hep, he);
}
if (mLock) PR_Unlock(mLock);
return res;
}
// XXX This method was called _hashEnumerateCopy, but it didn't copy the element!
// I don't know how this was supposed to work since the elements are neither copied
// nor refcounted.
static PR_CALLBACK PRIntn _hashEnumerateShare(PLHashEntry *he, PRIntn i, void *arg)
{
nsHashtable *newHashtable = (nsHashtable *)arg;
newHashtable->Put((nsHashKey *) he->key, he->value);
return HT_ENUMERATE_NEXT;
}
nsHashtable * nsHashtable::Clone() {
PRBool threadSafe = PR_FALSE;
if (mLock)
threadSafe = PR_TRUE;
nsHashtable *newHashTable = new nsHashtable(hashtable->nentries, threadSafe);
PL_HashTableEnumerateEntries(hashtable, _hashEnumerateShare, newHashTable);
return newHashTable;
}
void nsHashtable::Enumerate(nsHashtableEnumFunc aEnumFunc, void* closure) {
_HashEnumerateArgs thunk;
thunk.fn = aEnumFunc;
thunk.arg = closure;
PL_HashTableEnumerateEntries(hashtable, _hashEnumerate, &thunk);
}
static PR_CALLBACK PRIntn _hashEnumerateRemove(PLHashEntry *he, PRIntn i, void *arg)
{
_HashEnumerateArgs* thunk = (_HashEnumerateArgs*)arg;
if (thunk)
return thunk->fn((nsHashKey *) he->key, he->value, thunk->arg)
? HT_ENUMERATE_REMOVE
: HT_ENUMERATE_STOP;
else
return HT_ENUMERATE_REMOVE;
}
void nsHashtable::Reset() {
Reset(NULL);
}
void nsHashtable::Reset(nsHashtableEnumFunc destroyFunc, void* closure)
{
if (destroyFunc != NULL)
{
_HashEnumerateArgs thunk;
thunk.fn = destroyFunc;
thunk.arg = closure;
PL_HashTableEnumerateEntries(hashtable, _hashEnumerateRemove, &thunk);
}
else
PL_HashTableEnumerateEntries(hashtable, _hashEnumerateRemove, NULL);
}
////////////////////////////////////////////////////////////////////////////////
nsStringKey::nsStringKey(const char* str)
{
mStr.Assign(str);
}
nsStringKey::nsStringKey(const PRUnichar* str)
{
mStr.Assign(str);
}
nsStringKey::nsStringKey(const nsStr& str)
{
mStr.Assign(str);
}
nsStringKey::~nsStringKey(void)
{
}
PRUint32 nsStringKey::HashValue(void) const
{
return nsStr::HashCode(mStr);
}
PRBool nsStringKey::Equals(const nsHashKey* aKey) const
{
return ((nsStringKey*)aKey)->mStr == mStr;
}
nsHashKey* nsStringKey::Clone() const
{
return new nsStringKey(mStr);
}
const nsString& nsStringKey::GetString() const
{
return mStr;
}
////////////////////////////////////////////////////////////////////////////////
// nsObjectHashtable: an nsHashtable where the elements are C++ objects to be
// deleted
nsObjectHashtable::nsObjectHashtable(nsHashtableCloneElementFunc cloneElementFun,
void* cloneElementClosure,
nsHashtableEnumFunc destroyElementFun,
void* destroyElementClosure,
PRUint32 aSize, PRBool threadSafe)
: nsHashtable(aSize, threadSafe),
mCloneElementFun(cloneElementFun),
mCloneElementClosure(cloneElementClosure),
mDestroyElementFun(destroyElementFun),
mDestroyElementClosure(destroyElementClosure)
{
}
nsObjectHashtable::~nsObjectHashtable()
{
Reset();
}
PR_CALLBACK PRIntn
nsObjectHashtable::CopyElement(PLHashEntry *he, PRIntn i, void *arg)
{
nsObjectHashtable *newHashtable = (nsObjectHashtable *)arg;
void* newElement =
newHashtable->mCloneElementFun((nsHashKey*)he->key, he->value,
newHashtable->mCloneElementClosure);
if (newElement == nsnull)
return HT_ENUMERATE_STOP;
newHashtable->Put((nsHashKey*)he->key, newElement);
return HT_ENUMERATE_NEXT;
}
nsHashtable*
nsObjectHashtable::Clone()
{
PRBool threadSafe = PR_FALSE;
if (mLock)
threadSafe = PR_TRUE;
nsObjectHashtable* newHashTable =
new nsObjectHashtable(mCloneElementFun, mCloneElementClosure,
mDestroyElementFun, mDestroyElementClosure,
hashtable->nentries, threadSafe);
PL_HashTableEnumerateEntries(hashtable, CopyElement, newHashTable);
return newHashTable;
}
void
nsObjectHashtable::Reset()
{
nsHashtable::Reset(mDestroyElementFun, mDestroyElementClosure);
}
PRBool
nsObjectHashtable::RemoveAndDelete(nsHashKey *aKey)
{
void *value = Remove(aKey);
if (value && mDestroyElementFun)
{
return (*mDestroyElementFun)(aKey, value, mDestroyElementClosure);
}
else
return PR_FALSE;
}
////////////////////////////////////////////////////////////////////////////////
// nsSupportsHashtable: an nsHashtable where the elements are nsISupports*
static PR_CALLBACK PRBool
_ReleaseElement(nsHashKey *aKey, void *aData, void* closure)
{
nsISupports* element = NS_STATIC_CAST(nsISupports*, aData);
NS_IF_RELEASE(element);
return PR_TRUE;
}
nsSupportsHashtable::~nsSupportsHashtable()
{
Enumerate(_ReleaseElement, nsnull);
}
void*
nsSupportsHashtable::Put(nsHashKey *aKey, void *aData)
{
nsISupports* element = NS_REINTERPRET_CAST(nsISupports*, aData);
NS_IF_ADDREF(element);
return nsHashtable::Put(aKey, aData);
}
void*
nsSupportsHashtable::Get(nsHashKey *aKey)
{
void* data = nsHashtable::Get(aKey);
if (!data)
return nsnull;
nsISupports* element = NS_REINTERPRET_CAST(nsISupports*, data);
NS_IF_ADDREF(element);
return data;
}
void*
nsSupportsHashtable::Remove(nsHashKey *aKey)
{
void* data = nsHashtable::Remove(aKey);
if (!data)
return nsnull;
nsISupports* element = NS_STATIC_CAST(nsISupports*, data);
NS_IF_RELEASE(element);
return data;
}
static PR_CALLBACK PRIntn
_hashEnumerateCopy(PLHashEntry *he, PRIntn i, void *arg)
{
nsHashtable *newHashtable = (nsHashtable *)arg;
nsISupports* element = NS_STATIC_CAST(nsISupports*, he->value);
NS_IF_ADDREF(element);
newHashtable->Put((nsHashKey*)he->key, he->value);
return HT_ENUMERATE_NEXT;
}
nsHashtable*
nsSupportsHashtable::Clone()
{
PRBool threadSafe = PR_FALSE;
if (mLock)
threadSafe = PR_TRUE;
nsSupportsHashtable* newHashTable =
new nsSupportsHashtable(hashtable->nentries, threadSafe);
PL_HashTableEnumerateEntries(hashtable, _hashEnumerateCopy, newHashTable);
return newHashTable;
}
void
nsSupportsHashtable::Reset()
{
Enumerate(_ReleaseElement, nsnull);
nsHashtable::Reset();
}
////////////////////////////////////////////////////////////////////////////////
// nsOpaqueKey: Where keys are opaque byte array blobs
//
// Note opaque keys are not copied by this constructor. If you want a private
// copy in each hash key, you must create one and pass it in to this function.
nsOpaqueKey::nsOpaqueKey(const char *aOpaqueKey, PRUint32 aKeyLength)
{
mOpaqueKey = aOpaqueKey;
mKeyLength = aKeyLength;
}
nsOpaqueKey::~nsOpaqueKey(void)
{
}
PRUint32
nsOpaqueKey::HashValue(void) const
{
PRUint32 h, i, k;
h = 0;
// Same hashing technique as for java.lang.String.hashCode()
if (mKeyLength <= 15) {
// A short key; Use a dense sampling to compute the hash code
for (i = 0; i < mKeyLength; i++)
h += 37 * mOpaqueKey[i];
} else {
// A long key; Use a sparse sampling to compute the hash code
k = mKeyLength >> 3;
for (i = 0; i < mKeyLength; i += k)
h += 39 * mOpaqueKey[i];
}
return h;
}
PRBool
nsOpaqueKey::Equals(const nsHashKey* aKey) const
{
nsOpaqueKey *otherKey = (nsOpaqueKey*)aKey;
if (mKeyLength != otherKey->mKeyLength)
return PR_FALSE;
return !(PRBool)memcmp(otherKey->mOpaqueKey, mOpaqueKey, mKeyLength);
}
nsHashKey*
nsOpaqueKey::Clone() const
{
return new nsOpaqueKey(mOpaqueKey, mKeyLength);
}
PRUint32
nsOpaqueKey::GetKeyLength() const
{
return mKeyLength;
}
const char*
nsOpaqueKey::GetKey() const
{
return mOpaqueKey;
}
////////////////////////////////////////////////////////////////////////////////