pjs/netwerk/cache/memcache/nsMemCache.cpp

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C++

/* -*- 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 Communicator client code, released
* March 31, 1998.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1998-1999 Netscape Communications Corporation. All
* Rights Reserved.
*
*/
/**
* nsMemCache is the implementation of an in-memory network-data
* cache, used to cache the responses to network retrieval commands.
* Each cache entry may contain both content, e.g. GIF image data, and
* associated metadata, e.g. HTTP headers. Each entry is indexed by
* two different keys: a record id number and an opaque key, which is
* created by the cache manager by combining the URI with a "secondary
* key", e.g. HTTP post data.
*/
#include "nsMemCache.h"
#include "nsMemCacheRecord.h"
#include "nsIGenericFactory.h"
#include "nsString.h"
#include "nsHashtable.h"
#include "nsHashtableEnumerator.h"
#include "nsEnumeratorUtils.h"
PRInt32 nsMemCache::gRecordSerialNumber = 0;
nsMemCache::nsMemCache()
: mNumEntries(0), mOccupancy(0), mEnabled(PR_TRUE),
mHashTable(0)
{
NS_INIT_REFCNT();
}
nsMemCache::~nsMemCache()
{
nsresult rv;
rv = RemoveAll();
NS_WARN_IF_FALSE(NS_SUCCEEDED(rv) && (mNumEntries == 0),
"Failure to shut down memory cache cleanly. "
"Somewhere, someone is holding references to at least one cache record");
delete mHashTable;
}
nsresult
nsMemCache::Init()
{
mHashTable = new nsHashtable(256);
if (!mHashTable)
return NS_ERROR_OUT_OF_MEMORY;
return NS_OK;
}
NS_IMPL_ISUPPORTS1(nsMemCache, nsINetDataCache)
NS_IMETHODIMP
nsMemCache::GetDescription(PRUnichar * *aDescription)
{
nsAutoString description;
description.AssignWithConversion("Memory Cache");
*aDescription = description.ToNewUnicode();
if (!*aDescription)
return NS_ERROR_OUT_OF_MEMORY;
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::Contains(const char *aKey, PRUint32 aKeyLength, PRBool *aFound)
{
nsOpaqueKey opaqueKey(aKey, aKeyLength);
*aFound = mHashTable->Exists(&opaqueKey);
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::GetCachedNetData(const char *aKey, PRUint32 aKeyLength,
nsINetDataCacheRecord* *aRecord)
{
nsresult rv;
nsMemCacheRecord* record = 0;
nsOpaqueKey opaqueKey(aKey, aKeyLength);
record = (nsMemCacheRecord*)mHashTable->Get(&opaqueKey);
// No existing cache database entry was found. Create a new one.
// This requires two mappings in the hash table:
// Record ID ==> record
// Opaque key ==> record
if (!record) {
record = new nsMemCacheRecord;
if (!record)
goto out_of_memory;
rv = record->Init(aKey, aKeyLength, ++gRecordSerialNumber, this);
if (NS_FAILED(rv)) goto out_of_memory;
// Index the record by opaque key
nsOpaqueKey opaqueKey2(record->mKey, record->mKeyLength);
mHashTable->Put(&opaqueKey2, record);
// Index the record by it's record ID
char *recordIDbytes = NS_REINTERPRET_CAST(char *, &record->mRecordID);
nsOpaqueKey opaqueKey3(recordIDbytes, sizeof record->mRecordID);
mHashTable->Put(&opaqueKey3, record);
// The hash table holds on to the record
record->AddRef();
mNumEntries++;
}
record->AddRef();
*aRecord = record;
return NS_OK;
out_of_memory:
delete record;
return NS_ERROR_OUT_OF_MEMORY;
}
NS_IMETHODIMP
nsMemCache::GetCachedNetDataByID(PRInt32 RecordID,
nsINetDataCacheRecord* *aRecord)
{
nsOpaqueKey opaqueKey(NS_REINTERPRET_CAST(const char *, &RecordID),
sizeof RecordID);
*aRecord = (nsINetDataCacheRecord*)mHashTable->Get(&opaqueKey);
if (*aRecord) {
NS_ADDREF(*aRecord);
return NS_OK;
}
return NS_ERROR_FAILURE;
}
NS_METHOD
nsMemCache::Delete(nsMemCacheRecord* aRecord)
{
nsMemCacheRecord *removedRecord;
char *recordIDbytes = NS_REINTERPRET_CAST(char *, &aRecord->mRecordID);
nsOpaqueKey opaqueRecordIDKey(recordIDbytes,
sizeof aRecord->mRecordID);
removedRecord = (nsMemCacheRecord*)mHashTable->Remove(&opaqueRecordIDKey);
NS_ASSERTION(removedRecord == aRecord, "memory cache database inconsistent");
nsOpaqueKey opaqueKey(aRecord->mKey, aRecord->mKeyLength);
removedRecord = (nsMemCacheRecord*)mHashTable->Remove(&opaqueKey);
NS_ASSERTION(removedRecord == aRecord, "memory cache database inconsistent");
PRUint32 bytesUsed = 0;
aRecord->GetStoredContentLength(&bytesUsed);
aRecord->Release();
mOccupancy -= bytesUsed;
mNumEntries--;
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::GetEnabled(PRBool *aEnabled)
{
NS_ENSURE_ARG(aEnabled);
*aEnabled = mEnabled;
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::SetEnabled(PRBool aEnabled)
{
mEnabled = aEnabled;
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::GetFlags(PRUint32 *aFlags)
{
NS_ENSURE_ARG(aFlags);
*aFlags = MEMORY_CACHE;
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::GetNumEntries(PRUint32 *aNumEntries)
{
NS_ENSURE_ARG(aNumEntries);
*aNumEntries = mNumEntries;
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::GetMaxEntries(PRUint32 *aMaxEntries)
{
NS_ENSURE_ARG(aMaxEntries);
*aMaxEntries = MEM_CACHE_MAX_ENTRIES;
return NS_OK;
}
static NS_METHOD
HashEntryConverter(nsHashKey *aKey, void *aValue,
void *unused, nsISupports **retval)
{
nsMemCacheRecord *record;
nsOpaqueKey *opaqueKey;
record = (nsMemCacheRecord*)aValue;
opaqueKey = (nsOpaqueKey*)aKey;
// Hash table keys that index cache entries by their record ID
// shouldn't be enumerated.
if ((opaqueKey->GetBufferLength() == sizeof(PRInt32))) {
#ifdef DEBUG
PRInt32 recordID;
record->GetRecordID(&recordID);
NS_ASSERTION(*((PRInt32*)opaqueKey->GetBuffer()) == recordID,
"Key has incorrect key length");
#endif
return NS_ERROR_FAILURE;
}
NS_IF_ADDREF(record);
*retval = NS_STATIC_CAST(nsISupports*, record);
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::NewCacheEntryIterator(nsISimpleEnumerator* *aIterator)
{
nsCOMPtr<nsIEnumerator> iterator;
NS_ENSURE_ARG(aIterator);
NS_NewHashtableEnumerator(mHashTable, HashEntryConverter,
mHashTable, getter_AddRefs(iterator));
return NS_NewAdapterEnumerator(aIterator, iterator);
}
NS_IMETHODIMP
nsMemCache::GetNextCache(nsINetDataCache* *aNextCache)
{
NS_ENSURE_ARG(aNextCache);
*aNextCache = mNextCache;
NS_IF_ADDREF(*aNextCache);
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::SetNextCache(nsINetDataCache* aNextCache)
{
mNextCache = aNextCache;
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::GetStorageInUse(PRUint32 *aStorageInUse)
{
NS_ENSURE_ARG(aStorageInUse);
// Convert from bytes to KB
*aStorageInUse = (mOccupancy >> 10);
return NS_OK;
}
NS_IMETHODIMP
nsMemCache::RemoveAll(void)
{
PRBool failed;
nsCOMPtr<nsISimpleEnumerator> iterator;
nsCOMPtr<nsISupports> recordSupports;
nsCOMPtr<nsINetDataCacheRecord> record;
nsresult rv;
failed = PR_FALSE;
rv = NewCacheEntryIterator(getter_AddRefs(iterator));
if (NS_FAILED(rv))
return rv;
PRBool notDone;
while (1) {
rv = iterator->HasMoreElements(&notDone);
if (NS_FAILED(rv)) return rv;
if (!notDone)
break;
iterator->GetNext(getter_AddRefs(recordSupports));
record = do_QueryInterface(recordSupports);
recordSupports = 0;
PRUint32 bytesUsed;
record->GetStoredContentLength(&bytesUsed);
rv = record->Delete();
if (NS_FAILED(rv)) {
failed = PR_TRUE;
continue;
}
}
if (failed)
return NS_ERROR_FAILURE;
return NS_OK;
}