gecko-dev/xpcom/ds/nsStaticNameTable.cpp

237 lines
6.8 KiB
C++

/* -*- 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/. */
/* Class to manage lookup of static names in a table. */
#include "nsCRT.h"
#include "nscore.h"
#include "mozilla/HashFunctions.h"
#include "nsISupportsImpl.h"
#define PL_ARENA_CONST_ALIGN_MASK 3
#include "nsStaticNameTable.h"
using namespace mozilla;
struct NameTableKey
{
NameTableKey(const nsAFlatCString* aKeyStr)
: mIsUnichar(false)
{
mKeyStr.m1b = aKeyStr;
}
NameTableKey(const nsAFlatString* aKeyStr)
: mIsUnichar(true)
{
mKeyStr.m2b = aKeyStr;
}
bool mIsUnichar;
union {
const nsAFlatCString* m1b;
const nsAFlatString* m2b;
} mKeyStr;
};
struct NameTableEntry : public PLDHashEntryHdr
{
// no ownership here!
const nsAFlatCString* mString;
int32_t mIndex;
};
static bool
matchNameKeysCaseInsensitive(PLDHashTable*, const PLDHashEntryHdr* aHdr,
const void* key)
{
const NameTableEntry* entry =
static_cast<const NameTableEntry *>(aHdr);
const NameTableKey *keyValue = static_cast<const NameTableKey*>(key);
const nsAFlatCString* entryKey = entry->mString;
if (keyValue->mIsUnichar) {
return keyValue->mKeyStr.m2b->
LowerCaseEqualsASCII(entryKey->get(), entryKey->Length());
}
return keyValue->mKeyStr.m1b->
LowerCaseEqualsASCII(entryKey->get(), entryKey->Length());
}
/*
* caseInsensitiveHashKey is just like PL_DHashStringKey except it
* uses (*s & ~0x20) instead of simply *s. This means that "aFOO" and
* "afoo" and "aFoo" will all hash to the same thing. It also means
* that some strings that aren't case-insensensitively equal will hash
* to the same value, but it's just a hash function so it doesn't
* matter.
*/
static PLDHashNumber
caseInsensitiveStringHashKey(PLDHashTable *table, const void *key)
{
PLDHashNumber h = 0;
const NameTableKey* tableKey = static_cast<const NameTableKey*>(key);
if (tableKey->mIsUnichar) {
for (const char16_t* s = tableKey->mKeyStr.m2b->get();
*s != '\0';
s++)
h = AddToHash(h, *s & ~0x20);
} else {
for (const unsigned char* s =
reinterpret_cast<const unsigned char*>
(tableKey->mKeyStr.m1b->get());
*s != '\0';
s++)
h = AddToHash(h, *s & ~0x20);
}
return h;
}
static const struct PLDHashTableOps nametable_CaseInsensitiveHashTableOps = {
PL_DHashAllocTable,
PL_DHashFreeTable,
caseInsensitiveStringHashKey,
matchNameKeysCaseInsensitive,
PL_DHashMoveEntryStub,
PL_DHashClearEntryStub,
PL_DHashFinalizeStub,
nullptr,
};
nsStaticCaseInsensitiveNameTable::nsStaticCaseInsensitiveNameTable()
: mNameArray(nullptr), mNullStr("")
{
MOZ_COUNT_CTOR(nsStaticCaseInsensitiveNameTable);
mNameTable.ops = nullptr;
}
nsStaticCaseInsensitiveNameTable::~nsStaticCaseInsensitiveNameTable()
{
if (mNameArray) {
// manually call the destructor on placement-new'ed objects
for (uint32_t index = 0; index < mNameTable.entryCount; index++) {
mNameArray[index].~nsDependentCString();
}
nsMemory::Free((void*)mNameArray);
}
if (mNameTable.ops)
PL_DHashTableFinish(&mNameTable);
MOZ_COUNT_DTOR(nsStaticCaseInsensitiveNameTable);
}
bool
nsStaticCaseInsensitiveNameTable::Init(const char* const aNames[], int32_t Count)
{
NS_ASSERTION(!mNameArray, "double Init");
NS_ASSERTION(!mNameTable.ops, "double Init");
NS_ASSERTION(aNames, "null name table");
NS_ASSERTION(Count, "0 count");
mNameArray = (nsDependentCString*)
nsMemory::Alloc(Count * sizeof(nsDependentCString));
if (!mNameArray)
return false;
if (!PL_DHashTableInit(&mNameTable, &nametable_CaseInsensitiveHashTableOps,
nullptr, sizeof(NameTableEntry), Count,
fallible_t())) {
mNameTable.ops = nullptr;
return false;
}
for (int32_t index = 0; index < Count; ++index) {
const char* raw = aNames[index];
#ifdef DEBUG
{
// verify invariants of contents
nsAutoCString temp1(raw);
nsDependentCString temp2(raw);
ToLowerCase(temp1);
NS_ASSERTION(temp1.Equals(temp2), "upper case char in table");
NS_ASSERTION(nsCRT::IsAscii(raw),
"non-ascii string in table -- "
"case-insensitive matching won't work right");
}
#endif
// use placement-new to initialize the string object
nsDependentCString* strPtr = &mNameArray[index];
new (strPtr) nsDependentCString(raw);
NameTableKey key(strPtr);
NameTableEntry *entry =
static_cast<NameTableEntry*>
(PL_DHashTableOperate(&mNameTable, &key,
PL_DHASH_ADD));
if (!entry) continue;
NS_ASSERTION(entry->mString == 0, "Entry already exists!");
entry->mString = strPtr; // not owned!
entry->mIndex = index;
}
#ifdef DEBUG
PL_DHashMarkTableImmutable(&mNameTable);
#endif
return true;
}
int32_t
nsStaticCaseInsensitiveNameTable::Lookup(const nsACString& aName)
{
NS_ASSERTION(mNameArray, "not inited");
NS_ASSERTION(mNameTable.ops, "not inited");
const nsAFlatCString& str = PromiseFlatCString(aName);
NameTableKey key(&str);
NameTableEntry *entry =
static_cast<NameTableEntry*>
(PL_DHashTableOperate(&mNameTable, &key,
PL_DHASH_LOOKUP));
if (PL_DHASH_ENTRY_IS_FREE(entry))
return nsStaticCaseInsensitiveNameTable::NOT_FOUND;
return entry->mIndex;
}
int32_t
nsStaticCaseInsensitiveNameTable::Lookup(const nsAString& aName)
{
NS_ASSERTION(mNameArray, "not inited");
NS_ASSERTION(mNameTable.ops, "not inited");
const nsAFlatString& str = PromiseFlatString(aName);
NameTableKey key(&str);
NameTableEntry *entry =
static_cast<NameTableEntry*>
(PL_DHashTableOperate(&mNameTable, &key,
PL_DHASH_LOOKUP));
if (PL_DHASH_ENTRY_IS_FREE(entry))
return nsStaticCaseInsensitiveNameTable::NOT_FOUND;
return entry->mIndex;
}
const nsAFlatCString&
nsStaticCaseInsensitiveNameTable::GetStringValue(int32_t index)
{
NS_ASSERTION(mNameArray, "not inited");
NS_ASSERTION(mNameTable.ops, "not inited");
if ((NOT_FOUND < index) && ((uint32_t)index < mNameTable.entryCount)) {
return mNameArray[index];
}
return mNullStr;
}