diff options
Diffstat (limited to 'src/os.h')
| -rw-r--r-- | src/os.h | 139 |
1 files changed, 139 insertions, 0 deletions
@@ -298,4 +298,143 @@ 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)(void); + void *(*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_ */ |