/*

** 2001 September 16

**

** The author disclaims copyright to this source code.  In place of

** a legal notice, here is a blessing:

**

**    May you do good and not evil.

**    May you find forgiveness for yourself and forgive others.

**    May you share freely, never taking more than you give.

**

******************************************************************************

**

** This header file (together with is companion C source-code file

** "os.c") attempt to abstract the underlying operating system so that

** the SQLite library will work on both POSIX and windows systems.

*/

#ifndef _SQLITE_OS_H_

#define _SQLITE_OS_H_

/*

** Figure out if we are dealing with Unix, Windows, or some other

** operating system.

*/

#if !defined(OS_UNIX) && !defined(OS_OTHER)

# define OS_OTHER 0

# ifndef OS_WIN

#   if defined(_WIN32) || defined(WIN32) || defined(__CYGWIN__) || defined(__MINGW32__) || defined(__BORLANDC__)

#     define OS_WIN 1

#     define OS_UNIX 0

#     define OS_OS2 0

#   elif defined(_EMX_) || defined(_OS2) || defined(OS2) || defined(_OS2_) || defined(__OS2__)

#     define OS_WIN 0

#     define OS_UNIX 0

#     define OS_OS2 1

#   else

#     define OS_WIN 0

#     define OS_UNIX 1

#     define OS_OS2 0

#  endif

# else

#  define OS_UNIX 0

#  define OS_OS2 0

# endif

#else

# ifndef OS_WIN

#  define OS_WIN 0

# endif

#endif

#undef OS_WIN

#undef OS_UNIX

#undef OS_OS2

#undef OS_OTHER

/*

** Define the maximum size of a temporary filename

*/

#if OS_WIN

# include <windows.h>

# define SQLITE_TEMPNAME_SIZE (MAX_PATH+50)

#elif OS_OS2

# define INCL_DOSDATETIME

# define INCL_DOSFILEMGR

# define INCL_DOSERRORS

# define INCL_DOSMISC

# define INCL_DOSPROCESS

# include <os2.h>

# define SQLITE_TEMPNAME_SIZE (CCHMAXPATHCOMP)

#else

# define SQLITE_TEMPNAME_SIZE 200

#endif

/* If the SET_FULLSYNC macro is not defined above, then make it

** a no-op

*/

#ifndef SET_FULLSYNC

# define SET_FULLSYNC(x,y)

#endif

/*

** Temporary files are named starting with this prefix followed by 16 random

** alphanumeric characters, and no file extension. They are stored in the

** OS's standard temporary file directory, and are deleted prior to exit.

** If sqlite is being embedded in another program, you may wish to change the

** prefix to reflect your program's name, so that if your program exits

** prematurely, old temporary files can be easily identified. This can be done

** using -DTEMP_FILE_PREFIX=myprefix_ on the compiler command line.

*/

#ifndef TEMP_FILE_PREFIX

# define TEMP_FILE_PREFIX "sqlite_"

#endif

/*

** Define the interfaces for Unix, Windows, and OS/2.

*/

#if OS_UNIX

#define sqlite3OsOpenReadWrite      sqlite3UnixOpenReadWrite

#define sqlite3OsOpenExclusive      sqlite3UnixOpenExclusive

#define sqlite3OsOpenReadOnly       sqlite3UnixOpenReadOnly

#define sqlite3OsDelete             sqlite3UnixDelete

#define sqlite3OsFileExists         sqlite3UnixFileExists

#define sqlite3OsFullPathname       sqlite3UnixFullPathname

#define sqlite3OsIsDirWritable      sqlite3UnixIsDirWritable

#define sqlite3OsSyncDirectory      sqlite3UnixSyncDirectory

#define sqlite3OsTempFileName       sqlite3UnixTempFileName

#define sqlite3OsRandomSeed         sqlite3UnixRandomSeed

#define sqlite3OsSleep              sqlite3UnixSleep

#define sqlite3OsCurrentTime        sqlite3UnixCurrentTime

#define sqlite3OsEnterMutex         sqlite3UnixEnterMutex

#define sqlite3OsLeaveMutex         sqlite3UnixLeaveMutex

#define sqlite3OsInMutex            sqlite3UnixInMutex

#define sqlite3OsThreadSpecificData sqlite3UnixThreadSpecificData

#define sqlite3OsMalloc             sqlite3GenericMalloc

#define sqlite3OsRealloc            sqlite3GenericRealloc

#define sqlite3OsFree               sqlite3GenericFree

#define sqlite3OsAllocationSize     sqlite3GenericAllocationSize

#endif

#if OS_WIN

#define sqlite3OsOpenReadWrite      sqlite3WinOpenReadWrite

#define sqlite3OsOpenExclusive      sqlite3WinOpenExclusive

#define sqlite3OsOpenReadOnly       sqlite3WinOpenReadOnly

#define sqlite3OsDelete             sqlite3WinDelete

#define sqlite3OsFileExists         sqlite3WinFileExists

#define sqlite3OsFullPathname       sqlite3WinFullPathname

#define sqlite3OsIsDirWritable      sqlite3WinIsDirWritable

#define sqlite3OsSyncDirectory      sqlite3WinSyncDirectory

#define sqlite3OsTempFileName       sqlite3WinTempFileName

#define sqlite3OsRandomSeed         sqlite3WinRandomSeed

#define sqlite3OsSleep              sqlite3WinSleep

#define sqlite3OsCurrentTime        sqlite3WinCurrentTime

#define sqlite3OsEnterMutex         sqlite3WinEnterMutex

#define sqlite3OsLeaveMutex         sqlite3WinLeaveMutex

#define sqlite3OsInMutex            sqlite3WinInMutex

#define sqlite3OsThreadSpecificData sqlite3WinThreadSpecificData

#define sqlite3OsMalloc             sqlite3GenericMalloc

#define sqlite3OsRealloc            sqlite3GenericRealloc

#define sqlite3OsFree               sqlite3GenericFree

#define sqlite3OsAllocationSize     sqlite3GenericAllocationSize

#endif

#if OS_OS2

#define sqlite3OsOpenReadWrite      sqlite3Os2OpenReadWrite

#define sqlite3OsOpenExclusive      sqlite3Os2OpenExclusive

#define sqlite3OsOpenReadOnly       sqlite3Os2OpenReadOnly

#define sqlite3OsDelete             sqlite3Os2Delete

#define sqlite3OsFileExists         sqlite3Os2FileExists

#define sqlite3OsFullPathname       sqlite3Os2FullPathname

#define sqlite3OsIsDirWritable      sqlite3Os2IsDirWritable

#define sqlite3OsSyncDirectory      sqlite3Os2SyncDirectory

#define sqlite3OsTempFileName       sqlite3Os2TempFileName

#define sqlite3OsRandomSeed         sqlite3Os2RandomSeed

#define sqlite3OsSleep              sqlite3Os2Sleep

#define sqlite3OsCurrentTime        sqlite3Os2CurrentTime

#define sqlite3OsEnterMutex         sqlite3Os2EnterMutex

#define sqlite3OsLeaveMutex         sqlite3Os2LeaveMutex

#define sqlite3OsInMutex            sqlite3Os2InMutex

#define sqlite3OsThreadSpecificData sqlite3Os2ThreadSpecificData

#define sqlite3OsMalloc             sqlite3GenericMalloc

#define sqlite3OsRealloc            sqlite3GenericRealloc

#define sqlite3OsFree               sqlite3GenericFree

#define sqlite3OsAllocationSize     sqlite3GenericAllocationSize

#endif

#if OS_SYMBIAN

#define sqlite3OsOpenReadWrite      sqlite3SymbianOpenReadWrite

#define sqlite3OsOpenExclusive      sqlite3SymbianOpenExclusive

#define sqlite3OsOpenReadOnly       sqlite3SymbianOpenReadOnly

#define sqlite3OsDelete             sqlite3SymbianDelete

#define sqlite3OsFileExists         sqlite3SymbianFileExists

#define sqlite3OsFullPathname       sqlite3SymbianFullPathname

#define sqlite3OsIsDirWritable      sqlite3SymbianIsDirWritable

#define sqlite3OsSyncDirectory      sqlite3SymbianSyncDirectory

#define sqlite3OsTempFileName       sqlite3SymbianTempFileName

#define sqlite3OsRandomSeed         sqlite3SymbianRandomSeed

#define sqlite3OsSleep              sqlite3SymbianSleep

#define sqlite3OsCurrentTime        sqlite3SymbianCurrentTime

#define sqlite3OsEnterMutex         sqlite3SymbianEnterMutex

#define sqlite3OsLeaveMutex         sqlite3SymbianLeaveMutex

#define sqlite3OsInMutex            sqlite3SymbianInMutex

#define sqlite3OsThreadSpecificData sqlite3SymbianThreadSpecificData

#define sqlite3OsMalloc             sqlite3SymbianMalloc

#define sqlite3OsRealloc            sqlite3SymbianRealloc

#define sqlite3OsFree               sqlite3SymbianFree

#define sqlite3OsAllocationSize     sqlite3SymbianAllocationSize

#endif

/*

** If using an alternative OS interface, then we must have an "os_other.h"

** header file available for that interface.  Presumably the "os_other.h"

** header file contains #defines similar to those above.

*/

#if OS_OTHER

# include "os_other.h"

#endif

/*

** Forward declarations

*/

typedef struct OsFile OsFile;

typedef struct IoMethod IoMethod;

/*

** An instance of the following structure contains pointers to all

** methods on an OsFile object.

*/

struct IoMethod {

  int (*xClose)(OsFile**);

  int (*xOpenDirectory)(OsFile*, const char*);

  int (*xRead)(OsFile*, void*, int amt);

  int (*xWrite)(OsFile*, const void*, int amt);

  int (*xSeek)(OsFile*, i64 offset);

  int (*xTruncate)(OsFile*, i64 size);

  int (*xSync)(OsFile*, int);

  void (*xSetFullSync)(OsFile *id, int setting);

  int (*xFileHandle)(OsFile *id);

  int (*xFileSize)(OsFile*, i64 *pSize);

  int (*xLock)(OsFile*, int);

  int (*xUnlock)(OsFile*, int);

  int (*xLockState)(OsFile *id);

  int (*xCheckReservedLock)(OsFile *id);

};

/*

** The OsFile object describes an open disk file in an OS-dependent way.

** The version of OsFile defined here is a generic version.  Each OS

** implementation defines its own subclass of this structure that contains

** additional information needed to handle file I/O.  But the pMethod

** entry (pointing to the virtual function table) always occurs first

** so that we can always find the appropriate methods.

*/

struct OsFile {

  IoMethod const *pMethod;

};

/*

** The following values may be passed as the second argument to

** sqlite3OsLock(). The various locks exhibit the following semantics:

**

** SHARED:    Any number of processes may hold a SHARED lock simultaneously.

** RESERVED:  A single process may hold a RESERVED lock on a file at

**            any time. Other processes may hold and obtain new SHARED locks.

** PENDING:   A single process may hold a PENDING lock on a file at

**            any one time. Existing SHARED locks may persist, but no new

**            SHARED locks may be obtained by other processes.

** EXCLUSIVE: An EXCLUSIVE lock precludes all other locks.

**

** PENDING_LOCK may not be passed directly to sqlite3OsLock(). Instead, a

** process that requests an EXCLUSIVE lock may actually obtain a PENDING

** lock. This can be upgraded to an EXCLUSIVE lock by a subsequent call to

** sqlite3OsLock().

*/

#define NO_LOCK         0

#define SHARED_LOCK     1

#define RESERVED_LOCK   2

#define PENDING_LOCK    3

#define EXCLUSIVE_LOCK  4

/*

** File Locking Notes:  (Mostly about windows but also some info for Unix)

**

** We cannot use LockFileEx() or UnlockFileEx() on Win95/98/ME because

** those functions are not available.  So we use only LockFile() and

** UnlockFile().

**

** LockFile() prevents not just writing but also reading by other processes.

** A SHARED_LOCK is obtained by locking a single randomly-chosen 

** byte out of a specific range of bytes. The lock byte is obtained at 

** random so two separate readers can probably access the file at the 

** same time, unless they are unlucky and choose the same lock byte.

** An EXCLUSIVE_LOCK is obtained by locking all bytes in the range.

** There can only be one writer.  A RESERVED_LOCK is obtained by locking

** a single byte of the file that is designated as the reserved lock byte.

** A PENDING_LOCK is obtained by locking a designated byte different from

** the RESERVED_LOCK byte.

**

** On WinNT/2K/XP systems, LockFileEx() and UnlockFileEx() are available,

** which means we can use reader/writer locks.  When reader/writer locks

** are used, the lock is placed on the same range of bytes that is used

** for probabilistic locking in Win95/98/ME.  Hence, the locking scheme

** will support two or more Win95 readers or two or more WinNT readers.

** But a single Win95 reader will lock out all WinNT readers and a single

** WinNT reader will lock out all other Win95 readers.

**

** The following #defines specify the range of bytes used for locking.

** SHARED_SIZE is the number of bytes available in the pool from which

** a random byte is selected for a shared lock.  The pool of bytes for

** shared locks begins at SHARED_FIRST. 

**

** These #defines are available in sqlite_aux.h so that adaptors for

** connecting SQLite to other operating systems can use the same byte

** ranges for locking.  In particular, the same locking strategy and

** byte ranges are used for Unix.  This leaves open the possiblity of having

** clients on win95, winNT, and unix all talking to the same shared file

** and all locking correctly.  To do so would require that samba (or whatever

** tool is being used for file sharing) implements locks correctly between

** windows and unix.  I'm guessing that isn't likely to happen, but by

** using the same locking range we are at least open to the possibility.

**

** Locking in windows is manditory.  For this reason, we cannot store

** actual data in the bytes used for locking.  The pager never allocates

** the pages involved in locking therefore.  SHARED_SIZE is selected so

** that all locks will fit on a single page even at the minimum page size.

** PENDING_BYTE defines the beginning of the locks.  By default PENDING_BYTE

** is set high so that we don't have to allocate an unused page except

** for very large databases.  But one should test the page skipping logic 

** by setting PENDING_BYTE low and running the entire regression suite.

**

** Changing the value of PENDING_BYTE results in a subtly incompatible

** file format.  Depending on how it is changed, you might not notice

** the incompatibility right away, even running a full regression test.

** The default location of PENDING_BYTE is the first byte past the

** 1GB boundary.

**

*/

#ifndef SQLITE_TEST

#define PENDING_BYTE      0x40000000  /* First byte past the 1GB boundary */

#else

extern unsigned int sqlite3_pending_byte;

#define PENDING_BYTE sqlite3_pending_byte

#endif

#define RESERVED_BYTE     (PENDING_BYTE+1)

#define SHARED_FIRST      (PENDING_BYTE+2)

#define SHARED_SIZE       510

/*

** Prototypes for operating system interface routines.

*/

int sqlite3OsClose(OsFile**);

int sqlite3OsOpenDirectory(OsFile*, const char*);

int sqlite3OsRead(OsFile*, void*, int amt);

int sqlite3OsWrite(OsFile*, const void*, int amt);

int sqlite3OsSeek(OsFile*, i64 offset);

int sqlite3OsTruncate(OsFile*, i64 size);

int sqlite3OsSync(OsFile*, int);

void sqlite3OsSetFullSync(OsFile *id, int setting);

int sqlite3OsFileHandle(OsFile *id);

int sqlite3OsFileSize(OsFile*, i64 *pSize);

int sqlite3OsLock(OsFile*, int);

int sqlite3OsUnlock(OsFile*, int);

int sqlite3OsLockState(OsFile *id);

int sqlite3OsCheckReservedLock(OsFile *id);

int sqlite3OsOpenReadWrite(const char*, OsFile**, int*);

int sqlite3OsOpenExclusive(const char*, OsFile**, int);

int sqlite3OsOpenReadOnly(const char*, OsFile**);

int sqlite3OsDelete(const char*);

int sqlite3OsFileExists(const char*);

char *sqlite3OsFullPathname(const char*);

int sqlite3OsIsDirWritable(char*);

int sqlite3OsSyncDirectory(const char*);

int sqlite3OsTempFileName(char*);

int sqlite3OsRandomSeed(char*);

int sqlite3OsSleep(int ms);

int sqlite3OsCurrentTime(double*);

void sqlite3OsEnterMutex(void);

void sqlite3OsLeaveMutex(void);

int sqlite3OsInMutex(int);

ThreadData *sqlite3OsThreadSpecificData(int);

void *sqlite3OsMalloc(int);

void *sqlite3OsRealloc(void *, int);

void sqlite3OsFree(void *);

int sqlite3OsAllocationSize(void *);

/*

** If the SQLITE_ENABLE_REDEF_IO macro is defined, then the OS-layer

** interface routines are not called directly but are invoked using

** pointers to functions.  This allows the implementation of various

** OS-layer interface routines to be modified at run-time.  There are

** obscure but legitimate reasons for wanting to do this.  But for

** most users, a direct call to the underlying interface is preferable

** so the the redefinable I/O interface is turned off by default.

*/

#ifdef SQLITE_ENABLE_REDEF_IO

/*

** When redefinable I/O is enabled, a single global instance of the

** following structure holds pointers to the routines that SQLite 

** uses to talk with the underlying operating system.  Modify this

** structure (before using any SQLite API!) to accomodate perculiar

** operating system interfaces or behaviors.

*/

struct sqlite3OsVtbl {

  int (*xOpenReadWrite)(const char*, OsFile**, int*);

  int (*xOpenExclusive)(const char*, OsFile**, int);

  int (*xOpenReadOnly)(const char*, OsFile**);

  int (*xDelete)(const char*);

  int (*xFileExists)(const char*);

  char *(*xFullPathname)(const char*);

  int (*xIsDirWritable)(char*);

  int (*xSyncDirectory)(const char*);

  int (*xTempFileName)(char*);

  int (*xRandomSeed)(char*);

  int (*xSleep)(int ms);

  int (*xCurrentTime)(double*);

  void (*xEnterMutex)(void);

  void (*xLeaveMutex)(void);

  int (*xInMutex)(int);

  ThreadData *(*xThreadSpecificData)(int);

  void *(*xMalloc)(int);

  void *(*xRealloc)(void *, int);

  void (*xFree)(void *);

  int (*xAllocationSize)(void *);

};

/* Macro used to comment out routines that do not exists when there is

** no disk I/O 

*/

#ifdef SQLITE_OMIT_DISKIO

# define IF_DISKIO(X)  0

#else

# define IF_DISKIO(X)  X

#endif

#ifdef _SQLITE_OS_C_

  /*

  ** The os.c file implements the global virtual function table.

  */

  struct sqlite3OsVtbl sqlite3Os = {

    IF_DISKIO( sqlite3OsOpenReadWrite ),

    IF_DISKIO( sqlite3OsOpenExclusive ),

    IF_DISKIO( sqlite3OsOpenReadOnly ),

    IF_DISKIO( sqlite3OsDelete ),

    IF_DISKIO( sqlite3OsFileExists ),

    IF_DISKIO( sqlite3OsFullPathname ),

    IF_DISKIO( sqlite3OsIsDirWritable ),

    IF_DISKIO( sqlite3OsSyncDirectory ),

    IF_DISKIO( sqlite3OsTempFileName ),

    sqlite3OsRandomSeed,

    sqlite3OsSleep,

    sqlite3OsCurrentTime,

    sqlite3OsEnterMutex,

    sqlite3OsLeaveMutex,

    sqlite3OsInMutex,

    sqlite3OsThreadSpecificData,

    sqlite3OsMalloc,

    sqlite3OsRealloc,

    sqlite3OsFree,

    sqlite3OsAllocationSize

  };

#else

  /*

  ** Files other than os.c just reference the global virtual function table. 

  */

  extern struct sqlite3OsVtbl sqlite3Os;

#endif /* _SQLITE_OS_C_ */

/* This additional API routine is available with redefinable I/O */

struct sqlite3OsVtbl *sqlite3_os_switch(void);

/*

** Redefine the OS interface to go through the virtual function table

** rather than calling routines directly.

*/

#undef sqlite3OsOpenReadWrite

#undef sqlite3OsOpenExclusive

#undef sqlite3OsOpenReadOnly

#undef sqlite3OsDelete

#undef sqlite3OsFileExists

#undef sqlite3OsFullPathname

#undef sqlite3OsIsDirWritable

#undef sqlite3OsSyncDirectory

#undef sqlite3OsTempFileName

#undef sqlite3OsRandomSeed

#undef sqlite3OsSleep

#undef sqlite3OsCurrentTime

#undef sqlite3OsEnterMutex

#undef sqlite3OsLeaveMutex

#undef sqlite3OsInMutex

#undef sqlite3OsThreadSpecificData

#undef sqlite3OsMalloc

#undef sqlite3OsRealloc

#undef sqlite3OsFree

#undef sqlite3OsAllocationSize

#define sqlite3OsOpenReadWrite      sqlite3Os.xOpenReadWrite

#define sqlite3OsOpenExclusive      sqlite3Os.xOpenExclusive

#define sqlite3OsOpenReadOnly       sqlite3Os.xOpenReadOnly

#define sqlite3OsDelete             sqlite3Os.xDelete

#define sqlite3OsFileExists         sqlite3Os.xFileExists

#define sqlite3OsFullPathname       sqlite3Os.xFullPathname

#define sqlite3OsIsDirWritable      sqlite3Os.xIsDirWritable

#define sqlite3OsSyncDirectory      sqlite3Os.xSyncDirectory

#define sqlite3OsTempFileName       sqlite3Os.xTempFileName

#define sqlite3OsRandomSeed         sqlite3Os.xRandomSeed

#define sqlite3OsSleep              sqlite3Os.xSleep

#define sqlite3OsCurrentTime        sqlite3Os.xCurrentTime

#define sqlite3OsEnterMutex         sqlite3Os.xEnterMutex

#define sqlite3OsLeaveMutex         sqlite3Os.xLeaveMutex

#define sqlite3OsInMutex            sqlite3Os.xInMutex

#define sqlite3OsThreadSpecificData sqlite3Os.xThreadSpecificData

#define sqlite3OsMalloc             sqlite3Os.xMalloc

#define sqlite3OsRealloc            sqlite3Os.xRealloc

#define sqlite3OsFree               sqlite3Os.xFree

#define sqlite3OsAllocationSize     sqlite3Os.xAllocationSize

#endif /* SQLITE_ENABLE_REDEF_IO */

#endif /* _SQLITE_OS_H_ */