/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */

/* vim: set ts=8 sts=4 et sw=4 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 _nsMemoryCacheDevice_h_

#define _nsMemoryCacheDevice_h_

#include "nsCacheDevice.h"

#include "PLDHashTable.h"

#include "nsCacheEntry.h"

class nsMemoryCacheDeviceInfo;

/******************************************************************************

 * nsMemoryCacheDevice

 ******************************************************************************/

class nsMemoryCacheDevice : public nsCacheDevice

{

public:

    nsMemoryCacheDevice();

    virtual ~nsMemoryCacheDevice();

    virtual nsresult        Init() override;

    virtual nsresult        Shutdown() override;

    virtual const char *    GetDeviceID(void) override;

    virtual nsresult        BindEntry( nsCacheEntry * entry ) override;

    virtual nsCacheEntry *  FindEntry( nsCString * key, bool *collision ) override;

    virtual void            DoomEntry( nsCacheEntry * entry ) override;

    virtual nsresult        DeactivateEntry( nsCacheEntry * entry ) override;

    virtual nsresult OpenInputStreamForEntry(nsCacheEntry *     entry,

                                             nsCacheAccessMode  mode,

                                             uint32_t           offset,

                                             nsIInputStream **  result) override;

    virtual nsresult OpenOutputStreamForEntry(nsCacheEntry *     entry,

                                              nsCacheAccessMode  mode,

                                              uint32_t           offset,

                                              nsIOutputStream ** result) override;

    virtual nsresult GetFileForEntry( nsCacheEntry *    entry,

                                      nsIFile **        result ) override;

    virtual nsresult OnDataSizeChange( nsCacheEntry * entry,

                                       int32_t deltaSize ) override;

    virtual nsresult Visit( nsICacheVisitor * visitor ) override;

    virtual nsresult EvictEntries(const char * clientID) override;

    nsresult EvictPrivateEntries();

    void             SetCapacity(int32_t  capacity);

    void             SetMaxEntrySize(int32_t  maxSizeInKilobytes);

    bool             EntryIsTooBig(int64_t entrySize);

    size_t           TotalSize();

private:

    friend class nsMemoryCacheDeviceInfo;

    enum      { DELETE_ENTRY        = true,

                DO_NOT_DELETE_ENTRY = false };

    void      AdjustMemoryLimits( int32_t  softLimit, int32_t  hardLimit);

    void      EvictEntry( nsCacheEntry * entry , bool deleteEntry);

    void      EvictEntriesIfNecessary();

    int       EvictionList(nsCacheEntry * entry, int32_t  deltaSize);

    typedef bool (*EvictionMatcherFn)(nsCacheEntry* entry, void* args);

    nsresult DoEvictEntries(EvictionMatcherFn matchFn, void* args);

#ifdef DEBUG

    void      CheckEntryCount();

#endif

    /*

     *  Data members

     */

    enum {

        kQueueCount = 24   // entries > 2^23 (8Mb) start in last queue

    };

    nsCacheEntryHashTable  mMemCacheEntries;

    bool                   mInitialized;

    PRCList                mEvictionList[kQueueCount];

    int32_t                mHardLimit;

    int32_t                mSoftLimit;

    int32_t                mTotalSize;

    int32_t                mInactiveSize;

    int32_t                mEntryCount;

    int32_t                mMaxEntryCount;

    int32_t                mMaxEntrySize; // internal unit is bytes

    // XXX what other stats do we want to keep?

};

/******************************************************************************

 * nsMemoryCacheDeviceInfo - used to call nsIVisitor for about:cache

 ******************************************************************************/

class nsMemoryCacheDeviceInfo : public nsICacheDeviceInfo {

public:

    NS_DECL_ISUPPORTS

    NS_DECL_NSICACHEDEVICEINFO

    explicit nsMemoryCacheDeviceInfo(nsMemoryCacheDevice* device)

        :   mDevice(device)

    {

    }

private:

    virtual ~nsMemoryCacheDeviceInfo() = default;

    nsMemoryCacheDevice* mDevice;

};

#endif // _nsMemoryCacheDevice_h_