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gecko-dev/xpcom/ds/nsHashtable.cpp

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/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
/* 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/.
* This Original Code has been modified by IBM Corporation.
* Modifications made by IBM described herein are
* Copyright (c) International Business Machines
* Corporation, 2000
*
* Modifications to Mozilla code or documentation
* identified per MPL Section 3.3
*
* Date Modified by Description of modification
* 04/20/2000 IBM Corp. Added PR_CALLBACK for Optlink use in OS2
*/
#include <string.h>
#include "prlog.h"
#include "prlock.h"
#include "nsHashtable.h"
#include "nsIObjectInputStream.h"
#include "nsIObjectOutputStream.h"
#include "nsCRTGlue.h"
#include "mozilla/HashFunctions.h"
using namespace mozilla;
struct HTEntry : PLDHashEntryHdr
{
nsHashKey* key;
void* value;
};
//
// Key operations
//
static bool
matchKeyEntry(PLDHashTable*, const PLDHashEntryHdr* entry,
const void* key)
{
const HTEntry* hashEntry =
static_cast<const HTEntry*>(entry);
if (hashEntry->key == key)
return true;
const nsHashKey* otherKey = reinterpret_cast<const nsHashKey*>(key);
return otherKey->Equals(hashEntry->key);
}
static PLDHashNumber
hashKey(PLDHashTable* table, const void* key)
{
const nsHashKey* hashKey = static_cast<const nsHashKey*>(key);
return hashKey->HashCode();
}
static void
clearHashEntry(PLDHashTable* table, PLDHashEntryHdr* entry)
{
HTEntry* hashEntry = static_cast<HTEntry*>(entry);
// leave it up to the nsHashKey destructor to free the "value"
delete hashEntry->key;
hashEntry->key = nullptr;
hashEntry->value = nullptr; // probably not necessary, but for
// sanity's sake
}
static const PLDHashTableOps hashtableOps = {
PL_DHashAllocTable,
PL_DHashFreeTable,
hashKey,
matchKeyEntry,
PL_DHashMoveEntryStub,
clearHashEntry,
PL_DHashFinalizeStub,
nullptr,
};
//
// Enumerator callback
//
struct _HashEnumerateArgs {
nsHashtableEnumFunc fn;
void* arg;
};
static PLDHashOperator
hashEnumerate(PLDHashTable* table, PLDHashEntryHdr* hdr, uint32_t i, void *arg)
{
_HashEnumerateArgs* thunk = (_HashEnumerateArgs*)arg;
HTEntry* entry = static_cast<HTEntry*>(hdr);
if (thunk->fn(entry->key, entry->value, thunk->arg))
return PL_DHASH_NEXT;
return PL_DHASH_STOP;
}
//
// HashKey
//
nsHashKey::~nsHashKey(void)
{
MOZ_COUNT_DTOR(nsHashKey);
}
nsresult
nsHashKey::Write(nsIObjectOutputStream* aStream) const
{
NS_NOTREACHED("oops");
return NS_ERROR_NOT_IMPLEMENTED;
}
nsHashtable::nsHashtable(uint32_t aInitSize, bool aThreadSafe)
: mLock(nullptr), mEnumerating(false)
{
MOZ_COUNT_CTOR(nsHashtable);
bool result = PL_DHashTableInit(&mHashtable, &hashtableOps, nullptr,
sizeof(HTEntry), aInitSize, fallible_t());
NS_ASSERTION(result, "Hashtable failed to initialize");
// make sure we detect this later
if (!result)
mHashtable.ops = nullptr;
if (aThreadSafe) {
mLock = PR_NewLock();
if (mLock == nullptr) {
// Cannot create a lock. If running on a multiprocessing system
// we are sure to die.
PR_ASSERT(mLock != nullptr);
}
}
}
nsHashtable::~nsHashtable() {
MOZ_COUNT_DTOR(nsHashtable);
if (mHashtable.ops)
PL_DHashTableFinish(&mHashtable);
if (mLock) PR_DestroyLock(mLock);
}
bool nsHashtable::Exists(nsHashKey *aKey)
{
if (mLock) PR_Lock(mLock);
if (!mHashtable.ops) {
if (mLock) PR_Unlock(mLock);
return false;
}
PLDHashEntryHdr *entry =
PL_DHashTableOperate(&mHashtable, aKey, PL_DHASH_LOOKUP);
bool exists = PL_DHASH_ENTRY_IS_BUSY(entry);
if (mLock) PR_Unlock(mLock);
return exists;
}
void *nsHashtable::Put(nsHashKey *aKey, void *aData)
{
void *res = nullptr;
if (!mHashtable.ops) return nullptr;
if (mLock) PR_Lock(mLock);
// shouldn't be adding an item during enumeration
PR_ASSERT(!mEnumerating);
HTEntry* entry =
static_cast<HTEntry*>
(PL_DHashTableOperate(&mHashtable, aKey, PL_DHASH_ADD));
if (entry) { // don't return early, or you'll be locked!
if (entry->key) {
// existing entry, need to boot the old value
res = entry->value;
entry->value = aData;
} else {
// new entry (leave res == null)
entry->key = aKey->Clone();
entry->value = aData;
}
}
if (mLock) PR_Unlock(mLock);
return res;
}
void *nsHashtable::Get(nsHashKey *aKey)
{
if (!mHashtable.ops) return nullptr;
if (mLock) PR_Lock(mLock);
HTEntry* entry =
static_cast<HTEntry*>
(PL_DHashTableOperate(&mHashtable, aKey, PL_DHASH_LOOKUP));
void *ret = PL_DHASH_ENTRY_IS_BUSY(entry) ? entry->value : nullptr;
if (mLock) PR_Unlock(mLock);
return ret;
}
void *nsHashtable::Remove(nsHashKey *aKey)
{
if (!mHashtable.ops) return nullptr;
if (mLock) PR_Lock(mLock);
// shouldn't be adding an item during enumeration
PR_ASSERT(!mEnumerating);
// need to see if the entry is actually there, in order to get the
// old value for the result
HTEntry* entry =
static_cast<HTEntry*>
(PL_DHashTableOperate(&mHashtable, aKey, PL_DHASH_LOOKUP));
void *res;
if (PL_DHASH_ENTRY_IS_FREE(entry)) {
// value wasn't in the table anyway
res = nullptr;
} else {
res = entry->value;
PL_DHashTableRawRemove(&mHashtable, entry);
}
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 PLDHashOperator
hashEnumerateShare(PLDHashTable *table, PLDHashEntryHdr *hdr,
uint32_t i, void *arg)
{
nsHashtable *newHashtable = (nsHashtable *)arg;
HTEntry * entry = static_cast<HTEntry*>(hdr);
newHashtable->Put(entry->key, entry->value);
return PL_DHASH_NEXT;
}
nsHashtable * nsHashtable::Clone()
{
if (!mHashtable.ops) return nullptr;
bool threadSafe = (mLock != nullptr);
nsHashtable *newHashTable = new nsHashtable(mHashtable.entryCount, threadSafe);
PL_DHashTableEnumerate(&mHashtable, hashEnumerateShare, newHashTable);
return newHashTable;
}
void nsHashtable::Enumerate(nsHashtableEnumFunc aEnumFunc, void* aClosure)
{
if (!mHashtable.ops) return;
bool wasEnumerating = mEnumerating;
mEnumerating = true;
_HashEnumerateArgs thunk;
thunk.fn = aEnumFunc;
thunk.arg = aClosure;
PL_DHashTableEnumerate(&mHashtable, hashEnumerate, &thunk);
mEnumerating = wasEnumerating;
}
static PLDHashOperator
hashEnumerateRemove(PLDHashTable*, PLDHashEntryHdr* hdr, uint32_t i, void *arg)
{
HTEntry* entry = static_cast<HTEntry*>(hdr);
_HashEnumerateArgs* thunk = (_HashEnumerateArgs*)arg;
if (thunk) {
return thunk->fn(entry->key, entry->value, thunk->arg)
? PL_DHASH_REMOVE
: PL_DHASH_STOP;
}
return PL_DHASH_REMOVE;
}
void nsHashtable::Reset() {
Reset(nullptr);
}
void nsHashtable::Reset(nsHashtableEnumFunc destroyFunc, void* aClosure)
{
if (!mHashtable.ops) return;
_HashEnumerateArgs thunk, *thunkp;
if (!destroyFunc) {
thunkp = nullptr;
} else {
thunkp = &thunk;
thunk.fn = destroyFunc;
thunk.arg = aClosure;
}
PL_DHashTableEnumerate(&mHashtable, hashEnumerateRemove, thunkp);
}
// nsISerializable helpers
nsHashtable::nsHashtable(nsIObjectInputStream* aStream,
nsHashtableReadEntryFunc aReadEntryFunc,
nsHashtableFreeEntryFunc aFreeEntryFunc,
nsresult *aRetVal)
: mLock(nullptr),
mEnumerating(false)
{
MOZ_COUNT_CTOR(nsHashtable);
bool threadSafe;
nsresult rv = aStream->ReadBoolean(&threadSafe);
if (NS_SUCCEEDED(rv)) {
if (threadSafe) {
mLock = PR_NewLock();
if (!mLock)
rv = NS_ERROR_OUT_OF_MEMORY;
}
if (NS_SUCCEEDED(rv)) {
uint32_t count;
rv = aStream->Read32(&count);
if (NS_SUCCEEDED(rv)) {
bool status =
PL_DHashTableInit(&mHashtable, &hashtableOps,
nullptr, sizeof(HTEntry), count,
fallible_t());
if (!status) {
mHashtable.ops = nullptr;
rv = NS_ERROR_OUT_OF_MEMORY;
} else {
for (uint32_t i = 0; i < count; i++) {
nsHashKey* key;
void *data;
rv = aReadEntryFunc(aStream, &key, &data);
if (NS_SUCCEEDED(rv)) {
Put(key, data);
// XXXbe must we clone key? can't we hand off
aFreeEntryFunc(aStream, key, nullptr);
}
}
}
}
}
}
*aRetVal = rv;
}
struct WriteEntryArgs {
nsIObjectOutputStream* mStream;
nsHashtableWriteDataFunc mWriteDataFunc;
nsresult mRetVal;
};
static bool
WriteEntry(nsHashKey *aKey, void *aData, void* aClosure)
{
WriteEntryArgs* args = (WriteEntryArgs*) aClosure;
nsIObjectOutputStream* stream = args->mStream;
nsresult rv = aKey->Write(stream);
if (NS_SUCCEEDED(rv))
rv = args->mWriteDataFunc(stream, aData);
args->mRetVal = rv;
return true;
}
nsresult
nsHashtable::Write(nsIObjectOutputStream* aStream,
nsHashtableWriteDataFunc aWriteDataFunc) const
{
if (!mHashtable.ops)
return NS_ERROR_OUT_OF_MEMORY;
bool threadSafe = (mLock != nullptr);
nsresult rv = aStream->WriteBoolean(threadSafe);
if (NS_FAILED(rv)) return rv;
// Write the entry count first, so we know how many key/value pairs to read.
uint32_t count = mHashtable.entryCount;
rv = aStream->Write32(count);
if (NS_FAILED(rv)) return rv;
// Write all key/value pairs in the table.
WriteEntryArgs args = {aStream, aWriteDataFunc};
const_cast<nsHashtable*>(this)->Enumerate(WriteEntry, (void*) &args);
return args.mRetVal;
}
////////////////////////////////////////////////////////////////////////////////
nsISupportsKey::nsISupportsKey(nsIObjectInputStream* aStream, nsresult *aResult)
: mKey(nullptr)
{
bool nonnull;
nsresult rv = aStream->ReadBoolean(&nonnull);
if (NS_SUCCEEDED(rv) && nonnull)
rv = aStream->ReadObject(true, &mKey);
*aResult = rv;
}
nsresult
nsISupportsKey::Write(nsIObjectOutputStream* aStream) const
{
bool nonnull = (mKey != nullptr);
nsresult rv = aStream->WriteBoolean(nonnull);
if (NS_SUCCEEDED(rv) && nonnull)
rv = aStream->WriteObject(mKey, true);
return rv;
}
// Copy Constructor
// We need to free mStr if the object is passed with mOwnership as OWN. As the
// destructor here is freeing mStr in that case, mStr is NOT getting leaked here.
nsCStringKey::nsCStringKey(const nsCStringKey& aKey)
: mStr(aKey.mStr), mStrLen(aKey.mStrLen), mOwnership(aKey.mOwnership)
{
if (mOwnership != NEVER_OWN) {
uint32_t len = mStrLen * sizeof(char);
char* str = reinterpret_cast<char*>(nsMemory::Alloc(len + sizeof(char)));
if (!str) {
// Pray we don't dangle!
mOwnership = NEVER_OWN;
} else {
// Use memcpy in case there are embedded NULs.
memcpy(str, mStr, len);
str[mStrLen] = '\0';
mStr = str;
mOwnership = OWN;
}
}
#ifdef DEBUG
mKeyType = CStringKey;
#endif
MOZ_COUNT_CTOR(nsCStringKey);
}
nsCStringKey::nsCStringKey(const nsAFlatCString& str)
: mStr(const_cast<char*>(str.get())),
mStrLen(str.Length()),
mOwnership(OWN_CLONE)
{
NS_ASSERTION(mStr, "null string key");
#ifdef DEBUG
mKeyType = CStringKey;
#endif
MOZ_COUNT_CTOR(nsCStringKey);
}
nsCStringKey::nsCStringKey(const nsACString& str)
: mStr(ToNewCString(str)),
mStrLen(str.Length()),
mOwnership(OWN)
{
NS_ASSERTION(mStr, "null string key");
#ifdef DEBUG
mKeyType = CStringKey;
#endif
MOZ_COUNT_CTOR(nsCStringKey);
}
nsCStringKey::nsCStringKey(const char* str, int32_t strLen, Ownership own)
: mStr((char*)str), mStrLen(strLen), mOwnership(own)
{
NS_ASSERTION(mStr, "null string key");
if (mStrLen == uint32_t(-1))
mStrLen = strlen(str);
#ifdef DEBUG
mKeyType = CStringKey;
#endif
MOZ_COUNT_CTOR(nsCStringKey);
}
nsCStringKey::~nsCStringKey(void)
{
if (mOwnership == OWN)
nsMemory::Free(mStr);
MOZ_COUNT_DTOR(nsCStringKey);
}
uint32_t
nsCStringKey::HashCode(void) const
{
return HashString(mStr, mStrLen);
}
bool
nsCStringKey::Equals(const nsHashKey* aKey) const
{
NS_ASSERTION(aKey->GetKeyType() == CStringKey, "mismatched key types");
nsCStringKey* other = (nsCStringKey*)aKey;
NS_ASSERTION(mStrLen != uint32_t(-1), "never called HashCode");
NS_ASSERTION(other->mStrLen != uint32_t(-1), "never called HashCode");
if (mStrLen != other->mStrLen)
return false;
return memcmp(mStr, other->mStr, mStrLen * sizeof(char)) == 0;
}
nsHashKey*
nsCStringKey::Clone() const
{
if (mOwnership == NEVER_OWN)
return new nsCStringKey(mStr, mStrLen, NEVER_OWN);
// Since this might hold binary data OR a string, we ensure that the
// clone string is zero terminated, but don't assume that the source
// string was so terminated.
uint32_t len = mStrLen * sizeof(char);
char* str = (char*)nsMemory::Alloc(len + sizeof(char));
if (str == nullptr)
return nullptr;
memcpy(str, mStr, len);
str[len] = 0;
return new nsCStringKey(str, mStrLen, OWN);
}
nsCStringKey::nsCStringKey(nsIObjectInputStream* aStream, nsresult *aResult)
: mStr(nullptr), mStrLen(0), mOwnership(OWN)
{
nsAutoCString str;
nsresult rv = aStream->ReadCString(str);
mStr = ToNewCString(str);
if (NS_SUCCEEDED(rv))
mStrLen = str.Length();
*aResult = rv;
MOZ_COUNT_CTOR(nsCStringKey);
}
nsresult
nsCStringKey::Write(nsIObjectOutputStream* aStream) const
{
return aStream->WriteStringZ(mStr);
}
////////////////////////////////////////////////////////////////////////////////
// Copy Constructor
// We need to free mStr if the object is passed with mOwnership as OWN. As the
// destructor here is freeing mStr in that case, mStr is NOT getting leaked here.
nsStringKey::nsStringKey(const nsStringKey& aKey)
: mStr(aKey.mStr), mStrLen(aKey.mStrLen), mOwnership(aKey.mOwnership)
{
if (mOwnership != NEVER_OWN) {
uint32_t len = mStrLen * sizeof(char16_t);
char16_t* str = reinterpret_cast<char16_t*>(nsMemory::Alloc(len + sizeof(char16_t)));
if (!str) {
// Pray we don't dangle!
mOwnership = NEVER_OWN;
} else {
// Use memcpy in case there are embedded NULs.
memcpy(str, mStr, len);
str[mStrLen] = 0;
mStr = str;
mOwnership = OWN;
}
}
#ifdef DEBUG
mKeyType = StringKey;
#endif
MOZ_COUNT_CTOR(nsStringKey);
}
nsStringKey::nsStringKey(const nsAFlatString& str)
: mStr((char16_t*)str.get()),
mStrLen(str.Length()),
mOwnership(OWN_CLONE)
{
NS_ASSERTION(mStr, "null string key");
#ifdef DEBUG
mKeyType = StringKey;
#endif
MOZ_COUNT_CTOR(nsStringKey);
}
nsStringKey::nsStringKey(const nsAString& str)
: mStr(ToNewUnicode(str)),
mStrLen(str.Length()),
mOwnership(OWN)
{
NS_ASSERTION(mStr, "null string key");
#ifdef DEBUG
mKeyType = StringKey;
#endif
MOZ_COUNT_CTOR(nsStringKey);
}
nsStringKey::nsStringKey(const char16_t* str, int32_t strLen, Ownership own)
: mStr((char16_t*)str), mStrLen(strLen), mOwnership(own)
{
NS_ASSERTION(mStr, "null string key");
if (mStrLen == uint32_t(-1))
mStrLen = NS_strlen(str);
#ifdef DEBUG
mKeyType = StringKey;
#endif
MOZ_COUNT_CTOR(nsStringKey);
}
nsStringKey::~nsStringKey(void)
{
if (mOwnership == OWN)
nsMemory::Free(mStr);
MOZ_COUNT_DTOR(nsStringKey);
}
uint32_t
nsStringKey::HashCode(void) const
{
return HashString(mStr, mStrLen);
}
bool
nsStringKey::Equals(const nsHashKey* aKey) const
{
NS_ASSERTION(aKey->GetKeyType() == StringKey, "mismatched key types");
nsStringKey* other = (nsStringKey*)aKey;
NS_ASSERTION(mStrLen != uint32_t(-1), "never called HashCode");
NS_ASSERTION(other->mStrLen != uint32_t(-1), "never called HashCode");
if (mStrLen != other->mStrLen)
return false;
return memcmp(mStr, other->mStr, mStrLen * sizeof(char16_t)) == 0;
}
nsHashKey*
nsStringKey::Clone() const
{
if (mOwnership == NEVER_OWN)
return new nsStringKey(mStr, mStrLen, NEVER_OWN);
uint32_t len = (mStrLen+1) * sizeof(char16_t);
char16_t* str = (char16_t*)nsMemory::Alloc(len);
if (str == nullptr)
return nullptr;
memcpy(str, mStr, len);
return new nsStringKey(str, mStrLen, OWN);
}
nsStringKey::nsStringKey(nsIObjectInputStream* aStream, nsresult *aResult)
: mStr(nullptr), mStrLen(0), mOwnership(OWN)
{
nsAutoString str;
nsresult rv = aStream->ReadString(str);
mStr = ToNewUnicode(str);
if (NS_SUCCEEDED(rv))
mStrLen = str.Length();
*aResult = rv;
MOZ_COUNT_CTOR(nsStringKey);
}
nsresult
nsStringKey::Write(nsIObjectOutputStream* aStream) const
{
return aStream->WriteWStringZ(mStr);
}
////////////////////////////////////////////////////////////////////////////////
// nsObjectHashtable: an nsHashtable where the elements are C++ objects to be
// deleted
nsObjectHashtable::nsObjectHashtable(nsHashtableCloneElementFunc cloneElementFun,
void* cloneElementClosure,
nsHashtableEnumFunc destroyElementFun,
void* destroyElementClosure,
uint32_t aSize, bool threadSafe)
: nsHashtable(aSize, threadSafe),
mCloneElementFun(cloneElementFun),
mCloneElementClosure(cloneElementClosure),
mDestroyElementFun(destroyElementFun),
mDestroyElementClosure(destroyElementClosure)
{
}
nsObjectHashtable::~nsObjectHashtable()
{
Reset();
}
PLDHashOperator
nsObjectHashtable::CopyElement(PLDHashTable* table,
PLDHashEntryHdr* hdr,
uint32_t i, void *arg)
{
nsObjectHashtable *newHashtable = (nsObjectHashtable *)arg;
HTEntry *entry = static_cast<HTEntry*>(hdr);
void* newElement =
newHashtable->mCloneElementFun(entry->key, entry->value,
newHashtable->mCloneElementClosure);
if (newElement == nullptr)
return PL_DHASH_STOP;
newHashtable->Put(entry->key, newElement);
return PL_DHASH_NEXT;
}
nsHashtable*
nsObjectHashtable::Clone()
{
if (!mHashtable.ops) return nullptr;
bool threadSafe = false;
if (mLock)
threadSafe = true;
nsObjectHashtable* newHashTable =
new nsObjectHashtable(mCloneElementFun, mCloneElementClosure,
mDestroyElementFun, mDestroyElementClosure,
mHashtable.entryCount, threadSafe);
PL_DHashTableEnumerate(&mHashtable, CopyElement, newHashTable);
return newHashTable;
}
void
nsObjectHashtable::Reset()
{
nsHashtable::Reset(mDestroyElementFun, mDestroyElementClosure);
}
bool
nsObjectHashtable::RemoveAndDelete(nsHashKey *aKey)
{
void *value = Remove(aKey);
if (value && mDestroyElementFun)
return !!(*mDestroyElementFun)(aKey, value, mDestroyElementClosure);
return false;
}
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