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Diffstat (limited to 'src/sqlite3_aux.h')
| -rw-r--r-- | src/sqlite3_aux.h | 229 |
1 files changed, 0 insertions, 229 deletions
diff --git a/src/sqlite3_aux.h b/src/sqlite3_aux.h deleted file mode 100644 index 7c60cf0e2..000000000 --- a/src/sqlite3_aux.h +++ /dev/null @@ -1,229 +0,0 @@ -/* -** 2006 January 05 -** -** 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 defines auxiliary interfaces to the SQLite library. -** This header file is a companion to the official "sqlite.h" interface -** file. The difference is that the extraordinary efforts are made to -** insure that the interface defined in "sqlite.h" is always backwards -** compatible. No such guarantees are made for the auxiliary interfaces -** defined in this header file. The interfaces defined here are subject -** to change in future releases of SQLite. -** -** We justify the volitility of the interfaces defined here by noting that -** these interfaces are designed not for users of the SQLite library but -** by code that wishes to expand and extend the SQLite library. Some -** knowledge of what SQLite is doing internally is necessary to use these -** interfaces. -** -** We have no intention of changing the interfaces defined in this file -** gratuitously. No interfaces will be changed without good reason. But -** on the other hand, if the quality and functionality of SQLite can be -** enhanced by modifying the interfaces found here, then we will do so. -** -** Since these interfaces are variable, it is suggested that they not -** be accessed as a shared library. Users of these interfaces should -** statically link. -** -** @(#) $Id: sqlite3_aux.h,v 1.1 2006/01/06 03:29:58 drh Exp $ -*/ -/* -** 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 - -/* -** A single global instance of the following structure holds pointers to -** the routines that SQLite uses to talk with the underlying operating -** system. Clever programmers can substitute alternative implementations -** of these routine (prior to using any SQLite API!) in order to modify -** the way SQLite interacts with its environment. For example, modifications -** could be supplied that allow SQLite to talk to a virtual file system. -*/ -extern 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 *); -} sqlite3Os; - -/* -** The following API routine returns a pointer to the sqlite3Os global -** variable. It is probably easier just to reference the global variable -** directly. This routine is provided for backwards compatibility with -** an older interface design. -*/ -struct sqlite3OsVtbl *sqlite3_os_switch(void); - - -/* -** The following are prototypes of convenience routines that simply -** call the corresponding routines in the OsFile.pMethod virtual -** function table. -*/ -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); |