/**
 * @file llapr.h
 * @author Phoenix
 * @date 2004-11-28
 * @brief Helper functions for using the apache portable runtime library.
 *
 * $LicenseInfo:firstyear=2004&license=viewerlgpl$
 * Second Life Viewer Source Code
 * Copyright (C) 2010, Linden Research, Inc.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation;
 * version 2.1 of the License only.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * Linden Research, Inc., 945 Battery Street, San Francisco, CA  94111  USA
 * $/LicenseInfo$
 */

#ifndef LL_LLAPR_H
#define LL_LLAPR_H

#if LL_LINUX
#include <sys/param.h>  // Need PATH_MAX in APR headers...
#endif

#include <memory>
#include <boost/noncopyable.hpp>
#include "llwin32headers.h"
#include "apr_thread_proc.h"
#include "apr_getopt.h"
#include "apr_signal.h"

#include "llstring.h"

#include "mutex.h"

struct apr_dso_handle_t;
/**
 * @brief Function which appropriately logs error or remains quiet on
 * APR_SUCCESS.
 * @return Returns <code>true</code> if status is an error condition.
 */
#define ll_apr_warn_status(status) _ll_apr_warn_status(status, __FILE__, __LINE__)
bool LL_COMMON_API _ll_apr_warn_status(apr_status_t status, const char* file, int line);

#define ll_apr_assert_status(status) _ll_apr_assert_status(status, __FILE__, __LINE__)
void LL_COMMON_API _ll_apr_assert_status(apr_status_t status, const char* file, int line);

extern "C" LL_COMMON_API apr_pool_t* gAPRPoolp; // Global APR memory pool

/**
 * @brief initialize the common apr constructs -- apr itself, the
 * global pool, and a mutex.
 */
void LL_COMMON_API ll_init_apr();

/**
 * @brief Cleanup those common apr constructs.
 */
void LL_COMMON_API ll_cleanup_apr();

bool LL_COMMON_API ll_apr_is_initialized();


//
//LL apr_pool
//manage apr_pool_t, destroy allocated apr_pool in the destruction function.
//
class LL_COMMON_API LLAPRPool
{
public:
    LLAPRPool(apr_pool_t *parent = NULL, apr_size_t size = 0, bool releasePoolFlag = true) ;
    virtual ~LLAPRPool() ;

    virtual apr_pool_t* getAPRPool() ;
    apr_status_t getStatus() {return mStatus ; }

protected:
    void releaseAPRPool() ;
    void createAPRPool() ;

protected:
    apr_pool_t*  mPool ;              //pointing to an apr_pool
    apr_pool_t*  mParent ;            //parent pool
    apr_size_t   mMaxSize ;           //max size of mPool, mPool should return memory to system if allocated memory beyond this limit. However it seems not to work.
    apr_status_t mStatus ;            //status when creating the pool
    bool         mReleasePoolFlag ;   //if set, mPool is destroyed when LLAPRPool is deleted. default value is true.
};

//
//volatile LL apr_pool
//which clears memory automatically.
//so it can not hold static data or data after memory is cleared
//
class LL_COMMON_API LLVolatileAPRPool : public LLAPRPool
{
public:
    LLVolatileAPRPool(bool is_local = true, apr_pool_t *parent = NULL, apr_size_t size = 0, bool releasePoolFlag = true);
    virtual ~LLVolatileAPRPool();

    /*virtual*/ apr_pool_t* getAPRPool() ; //define this virtual function to avoid any mistakenly calling LLAPRPool::getAPRPool().
    apr_pool_t* getVolatileAPRPool() ;
    void        clearVolatileAPRPool() ;

    bool        isFull() ;

private:
    S32 mNumActiveRef ; //number of active pointers pointing to the apr_pool.
    S32 mNumTotalRef ;  //number of total pointers pointing to the apr_pool since last creating.

    std::unique_ptr<std::mutex> mMutexp;
} ;

// File IO convenience functions.
// Returns NULL if the file fails to open, sets *sizep to file size if not NULL
// abbreviated flags
#define LL_APR_R (APR_READ) // "r"
#define LL_APR_W (APR_CREATE|APR_TRUNCATE|APR_WRITE) // "w"
#define LL_APR_A (APR_CREATE|APR_WRITE|APR_APPEND) // "w"
#define LL_APR_RB (APR_READ|APR_BINARY) // "rb"
#define LL_APR_WB (APR_CREATE|APR_TRUNCATE|APR_WRITE|APR_BINARY) // "wb"
#define LL_APR_AB (APR_CREATE|APR_WRITE|APR_BINARY|APR_APPEND)
#define LL_APR_RPB (APR_READ|APR_WRITE|APR_BINARY) // "r+b"
#define LL_APR_WPB (APR_CREATE|APR_TRUNCATE|APR_READ|APR_WRITE|APR_BINARY) // "w+b"

//
//apr_file manager
//which: 1)only keeps one file open;
//       2)closes the open file in the destruction function
//       3)informs the apr_pool to clean the memory when the file is closed.
//Note: please close an open file at the earliest convenience.
//      especially do not put some time-costly operations between open() and close().
//      otherwise it might lock the APRFilePool.
//there are two different apr_pools the APRFile can use:
//      1, a temporary pool passed to an APRFile function, which is used within this function and only once.
//      2, a global pool.
//

class LL_COMMON_API LLAPRFile : boost::noncopyable
{
    // make this non copyable since a copy closes the file
private:
    apr_file_t* mFile ;
    LLVolatileAPRPool *mCurrentFilePoolp ; //currently in use apr_pool, could be one of them: sAPRFilePoolp, or a temp pool.

public:
    LLAPRFile() ;
    LLAPRFile(const std::string& filename, apr_int32_t flags, LLVolatileAPRPool* pool = NULL);
    ~LLAPRFile() ;

    apr_status_t open(const std::string& filename, apr_int32_t flags, LLVolatileAPRPool* pool = NULL, S32* sizep = NULL);
    apr_status_t open(const std::string& filename, apr_int32_t flags, bool use_global_pool); //use gAPRPoolp.
    apr_status_t close() ;

    // Returns actual offset, -1 if seek fails
    S32 seek(apr_seek_where_t where, S32 offset);
    apr_status_t eof() { return apr_file_eof(mFile);}

    // Returns bytes read/written, 0 if read/write fails:
    S32 read(void* buf, S32 nbytes);
    S32 write(const void* buf, S32 nbytes);

    apr_file_t* getFileHandle() {return mFile;}

//
//*******************************************************************************************************************************
//static components
//
public:
    static LLVolatileAPRPool *sAPRFilePoolp ; //a global apr_pool for APRFile, which is used only when local pool does not exist.

private:
    static apr_file_t* open(const std::string& filename, apr_pool_t* apr_pool, apr_int32_t flags);
    static apr_status_t close(apr_file_t* file) ;
    static S32 seek(apr_file_t* file, apr_seek_where_t where, S32 offset);
public:
    // returns false if failure:
    static bool remove(const std::string& filename, LLVolatileAPRPool* pool = NULL);
    static bool rename(const std::string& filename, const std::string& newname, LLVolatileAPRPool* pool = NULL);
    static bool isExist(const std::string& filename, LLVolatileAPRPool* pool = NULL, apr_int32_t flags = APR_READ);
    static S32 size(const std::string& filename, LLVolatileAPRPool* pool = NULL);
    static bool makeDir(const std::string& dirname, LLVolatileAPRPool* pool = NULL);
    static bool removeDir(const std::string& dirname, LLVolatileAPRPool* pool = NULL);

    // Returns bytes read/written, 0 if read/write fails:
    static S32 readEx(const std::string& filename, void *buf, S32 offset, S32 nbytes, LLVolatileAPRPool* pool = NULL);
    static S32 writeEx(const std::string& filename, const void *buf, S32 offset, S32 nbytes, LLVolatileAPRPool* pool = NULL); // offset<0 means append
//*******************************************************************************************************************************
};


#endif // LL_LLAPR_H