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Diffstat (limited to 'lib/libsqlite3/src/test_demovfs.c')
| -rw-r--r-- | lib/libsqlite3/src/test_demovfs.c | 679 |
1 files changed, 0 insertions, 679 deletions
diff --git a/lib/libsqlite3/src/test_demovfs.c b/lib/libsqlite3/src/test_demovfs.c deleted file mode 100644 index 9410a309a6e..00000000000 --- a/lib/libsqlite3/src/test_demovfs.c +++ /dev/null @@ -1,679 +0,0 @@ -/* -** 2010 April 7 -** -** 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 file implements an example of a simple VFS implementation that -** omits complex features often not required or not possible on embedded -** platforms. Code is included to buffer writes to the journal file, -** which can be a significant performance improvement on some embedded -** platforms. -** -** OVERVIEW -** -** The code in this file implements a minimal SQLite VFS that can be -** used on Linux and other posix-like operating systems. The following -** system calls are used: -** -** File-system: access(), unlink(), getcwd() -** File IO: open(), read(), write(), fsync(), close(), fstat() -** Other: sleep(), usleep(), time() -** -** The following VFS features are omitted: -** -** 1. File locking. The user must ensure that there is at most one -** connection to each database when using this VFS. Multiple -** connections to a single shared-cache count as a single connection -** for the purposes of the previous statement. -** -** 2. The loading of dynamic extensions (shared libraries). -** -** 3. Temporary files. The user must configure SQLite to use in-memory -** temp files when using this VFS. The easiest way to do this is to -** compile with: -** -** -DSQLITE_TEMP_STORE=3 -** -** 4. File truncation. As of version 3.6.24, SQLite may run without -** a working xTruncate() call, providing the user does not configure -** SQLite to use "journal_mode=truncate", or use both -** "journal_mode=persist" and ATTACHed databases. -** -** It is assumed that the system uses UNIX-like path-names. Specifically, -** that '/' characters are used to separate path components and that -** a path-name is a relative path unless it begins with a '/'. And that -** no UTF-8 encoded paths are greater than 512 bytes in length. -** -** JOURNAL WRITE-BUFFERING -** -** To commit a transaction to the database, SQLite first writes rollback -** information into the journal file. This usually consists of 4 steps: -** -** 1. The rollback information is sequentially written into the journal -** file, starting at the start of the file. -** 2. The journal file is synced to disk. -** 3. A modification is made to the first few bytes of the journal file. -** 4. The journal file is synced to disk again. -** -** Most of the data is written in step 1 using a series of calls to the -** VFS xWrite() method. The buffers passed to the xWrite() calls are of -** various sizes. For example, as of version 3.6.24, when committing a -** transaction that modifies 3 pages of a database file that uses 4096 -** byte pages residing on a media with 512 byte sectors, SQLite makes -** eleven calls to the xWrite() method to create the rollback journal, -** as follows: -** -** Write offset | Bytes written -** ---------------------------- -** 0 512 -** 512 4 -** 516 4096 -** 4612 4 -** 4616 4 -** 4620 4096 -** 8716 4 -** 8720 4 -** 8724 4096 -** 12820 4 -** ++++++++++++SYNC+++++++++++ -** 0 12 -** ++++++++++++SYNC+++++++++++ -** -** On many operating systems, this is an efficient way to write to a file. -** However, on some embedded systems that do not cache writes in OS -** buffers it is much more efficient to write data in blocks that are -** an integer multiple of the sector-size in size and aligned at the -** start of a sector. -** -** To work around this, the code in this file allocates a fixed size -** buffer of SQLITE_DEMOVFS_BUFFERSZ using sqlite3_malloc() whenever a -** journal file is opened. It uses the buffer to coalesce sequential -** writes into aligned SQLITE_DEMOVFS_BUFFERSZ blocks. When SQLite -** invokes the xSync() method to sync the contents of the file to disk, -** all accumulated data is written out, even if it does not constitute -** a complete block. This means the actual IO to create the rollback -** journal for the example transaction above is this: -** -** Write offset | Bytes written -** ---------------------------- -** 0 8192 -** 8192 4632 -** ++++++++++++SYNC+++++++++++ -** 0 12 -** ++++++++++++SYNC+++++++++++ -** -** Much more efficient if the underlying OS is not caching write -** operations. -*/ - -#if !defined(SQLITE_TEST) || SQLITE_OS_UNIX - -#include "sqlite3.h" - -#include <assert.h> -#include <string.h> -#include <sys/types.h> -#include <sys/stat.h> -#include <sys/file.h> -#include <sys/param.h> -#include <unistd.h> -#include <time.h> -#include <errno.h> -#include <fcntl.h> - -/* -** Size of the write buffer used by journal files in bytes. -*/ -#ifndef SQLITE_DEMOVFS_BUFFERSZ -# define SQLITE_DEMOVFS_BUFFERSZ 8192 -#endif - -/* -** The maximum pathname length supported by this VFS. -*/ -#define MAXPATHNAME 512 - -/* -** When using this VFS, the sqlite3_file* handles that SQLite uses are -** actually pointers to instances of type DemoFile. -*/ -typedef struct DemoFile DemoFile; -struct DemoFile { - sqlite3_file base; /* Base class. Must be first. */ - int fd; /* File descriptor */ - - char *aBuffer; /* Pointer to malloc'd buffer */ - int nBuffer; /* Valid bytes of data in zBuffer */ - sqlite3_int64 iBufferOfst; /* Offset in file of zBuffer[0] */ -}; - -/* -** Write directly to the file passed as the first argument. Even if the -** file has a write-buffer (DemoFile.aBuffer), ignore it. -*/ -static int demoDirectWrite( - DemoFile *p, /* File handle */ - const void *zBuf, /* Buffer containing data to write */ - int iAmt, /* Size of data to write in bytes */ - sqlite_int64 iOfst /* File offset to write to */ -){ - off_t ofst; /* Return value from lseek() */ - size_t nWrite; /* Return value from write() */ - - ofst = lseek(p->fd, iOfst, SEEK_SET); - if( ofst!=iOfst ){ - return SQLITE_IOERR_WRITE; - } - - nWrite = write(p->fd, zBuf, iAmt); - if( nWrite!=iAmt ){ - return SQLITE_IOERR_WRITE; - } - - return SQLITE_OK; -} - -/* -** Flush the contents of the DemoFile.aBuffer buffer to disk. This is a -** no-op if this particular file does not have a buffer (i.e. it is not -** a journal file) or if the buffer is currently empty. -*/ -static int demoFlushBuffer(DemoFile *p){ - int rc = SQLITE_OK; - if( p->nBuffer ){ - rc = demoDirectWrite(p, p->aBuffer, p->nBuffer, p->iBufferOfst); - p->nBuffer = 0; - } - return rc; -} - -/* -** Close a file. -*/ -static int demoClose(sqlite3_file *pFile){ - int rc; - DemoFile *p = (DemoFile*)pFile; - rc = demoFlushBuffer(p); - sqlite3_free(p->aBuffer); - close(p->fd); - return rc; -} - -/* -** Read data from a file. -*/ -static int demoRead( - sqlite3_file *pFile, - void *zBuf, - int iAmt, - sqlite_int64 iOfst -){ - DemoFile *p = (DemoFile*)pFile; - off_t ofst; /* Return value from lseek() */ - int nRead; /* Return value from read() */ - int rc; /* Return code from demoFlushBuffer() */ - - /* Flush any data in the write buffer to disk in case this operation - ** is trying to read data the file-region currently cached in the buffer. - ** It would be possible to detect this case and possibly save an - ** unnecessary write here, but in practice SQLite will rarely read from - ** a journal file when there is data cached in the write-buffer. - */ - rc = demoFlushBuffer(p); - if( rc!=SQLITE_OK ){ - return rc; - } - - ofst = lseek(p->fd, iOfst, SEEK_SET); - if( ofst!=iOfst ){ - return SQLITE_IOERR_READ; - } - nRead = read(p->fd, zBuf, iAmt); - - if( nRead==iAmt ){ - return SQLITE_OK; - }else if( nRead>=0 ){ - return SQLITE_IOERR_SHORT_READ; - } - - return SQLITE_IOERR_READ; -} - -/* -** Write data to a crash-file. -*/ -static int demoWrite( - sqlite3_file *pFile, - const void *zBuf, - int iAmt, - sqlite_int64 iOfst -){ - DemoFile *p = (DemoFile*)pFile; - - if( p->aBuffer ){ - char *z = (char *)zBuf; /* Pointer to remaining data to write */ - int n = iAmt; /* Number of bytes at z */ - sqlite3_int64 i = iOfst; /* File offset to write to */ - - while( n>0 ){ - int nCopy; /* Number of bytes to copy into buffer */ - - /* If the buffer is full, or if this data is not being written directly - ** following the data already buffered, flush the buffer. Flushing - ** the buffer is a no-op if it is empty. - */ - if( p->nBuffer==SQLITE_DEMOVFS_BUFFERSZ || p->iBufferOfst+p->nBuffer!=i ){ - int rc = demoFlushBuffer(p); - if( rc!=SQLITE_OK ){ - return rc; - } - } - assert( p->nBuffer==0 || p->iBufferOfst+p->nBuffer==i ); - p->iBufferOfst = i - p->nBuffer; - - /* Copy as much data as possible into the buffer. */ - nCopy = SQLITE_DEMOVFS_BUFFERSZ - p->nBuffer; - if( nCopy>n ){ - nCopy = n; - } - memcpy(&p->aBuffer[p->nBuffer], z, nCopy); - p->nBuffer += nCopy; - - n -= nCopy; - i += nCopy; - z += nCopy; - } - }else{ - return demoDirectWrite(p, zBuf, iAmt, iOfst); - } - - return SQLITE_OK; -} - -/* -** Truncate a file. This is a no-op for this VFS (see header comments at -** the top of the file). -*/ -static int demoTruncate(sqlite3_file *pFile, sqlite_int64 size){ -#if 0 - if( ftruncate(((DemoFile *)pFile)->fd, size) ) return SQLITE_IOERR_TRUNCATE; -#endif - return SQLITE_OK; -} - -/* -** Sync the contents of the file to the persistent media. -*/ -static int demoSync(sqlite3_file *pFile, int flags){ - DemoFile *p = (DemoFile*)pFile; - int rc; - - rc = demoFlushBuffer(p); - if( rc!=SQLITE_OK ){ - return rc; - } - - rc = fsync(p->fd); - return (rc==0 ? SQLITE_OK : SQLITE_IOERR_FSYNC); -} - -/* -** Write the size of the file in bytes to *pSize. -*/ -static int demoFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){ - DemoFile *p = (DemoFile*)pFile; - int rc; /* Return code from fstat() call */ - struct stat sStat; /* Output of fstat() call */ - - /* Flush the contents of the buffer to disk. As with the flush in the - ** demoRead() method, it would be possible to avoid this and save a write - ** here and there. But in practice this comes up so infrequently it is - ** not worth the trouble. - */ - rc = demoFlushBuffer(p); - if( rc!=SQLITE_OK ){ - return rc; - } - - rc = fstat(p->fd, &sStat); - if( rc!=0 ) return SQLITE_IOERR_FSTAT; - *pSize = sStat.st_size; - return SQLITE_OK; -} - -/* -** Locking functions. The xLock() and xUnlock() methods are both no-ops. -** The xCheckReservedLock() always indicates that no other process holds -** a reserved lock on the database file. This ensures that if a hot-journal -** file is found in the file-system it is rolled back. -*/ -static int demoLock(sqlite3_file *pFile, int eLock){ - return SQLITE_OK; -} -static int demoUnlock(sqlite3_file *pFile, int eLock){ - return SQLITE_OK; -} -static int demoCheckReservedLock(sqlite3_file *pFile, int *pResOut){ - *pResOut = 0; - return SQLITE_OK; -} - -/* -** No xFileControl() verbs are implemented by this VFS. -*/ -static int demoFileControl(sqlite3_file *pFile, int op, void *pArg){ - return SQLITE_OK; -} - -/* -** The xSectorSize() and xDeviceCharacteristics() methods. These two -** may return special values allowing SQLite to optimize file-system -** access to some extent. But it is also safe to simply return 0. -*/ -static int demoSectorSize(sqlite3_file *pFile){ - return 0; -} -static int demoDeviceCharacteristics(sqlite3_file *pFile){ - return 0; -} - -/* -** Open a file handle. -*/ -static int demoOpen( - sqlite3_vfs *pVfs, /* VFS */ - const char *zName, /* File to open, or 0 for a temp file */ - sqlite3_file *pFile, /* Pointer to DemoFile struct to populate */ - int flags, /* Input SQLITE_OPEN_XXX flags */ - int *pOutFlags /* Output SQLITE_OPEN_XXX flags (or NULL) */ -){ - static const sqlite3_io_methods demoio = { - 1, /* iVersion */ - demoClose, /* xClose */ - demoRead, /* xRead */ - demoWrite, /* xWrite */ - demoTruncate, /* xTruncate */ - demoSync, /* xSync */ - demoFileSize, /* xFileSize */ - demoLock, /* xLock */ - demoUnlock, /* xUnlock */ - demoCheckReservedLock, /* xCheckReservedLock */ - demoFileControl, /* xFileControl */ - demoSectorSize, /* xSectorSize */ - demoDeviceCharacteristics /* xDeviceCharacteristics */ - }; - - DemoFile *p = (DemoFile*)pFile; /* Populate this structure */ - int oflags = 0; /* flags to pass to open() call */ - char *aBuf = 0; - - if( zName==0 ){ - return SQLITE_IOERR; - } - - if( flags&SQLITE_OPEN_MAIN_JOURNAL ){ - aBuf = (char *)sqlite3_malloc(SQLITE_DEMOVFS_BUFFERSZ); - if( !aBuf ){ - return SQLITE_NOMEM; - } - } - - if( flags&SQLITE_OPEN_EXCLUSIVE ) oflags |= O_EXCL; - if( flags&SQLITE_OPEN_CREATE ) oflags |= O_CREAT; - if( flags&SQLITE_OPEN_READONLY ) oflags |= O_RDONLY; - if( flags&SQLITE_OPEN_READWRITE ) oflags |= O_RDWR; - - memset(p, 0, sizeof(DemoFile)); - p->fd = open(zName, oflags, 0600); - if( p->fd<0 ){ - sqlite3_free(aBuf); - return SQLITE_CANTOPEN; - } - p->aBuffer = aBuf; - - if( pOutFlags ){ - *pOutFlags = flags; - } - p->base.pMethods = &demoio; - return SQLITE_OK; -} - -/* -** Delete the file identified by argument zPath. If the dirSync parameter -** is non-zero, then ensure the file-system modification to delete the -** file has been synced to disk before returning. -*/ -static int demoDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){ - int rc; /* Return code */ - - rc = unlink(zPath); - if( rc!=0 && errno==ENOENT ) return SQLITE_OK; - - if( rc==0 && dirSync ){ - int dfd; /* File descriptor open on directory */ - int i; /* Iterator variable */ - char zDir[MAXPATHNAME+1]; /* Name of directory containing file zPath */ - - /* Figure out the directory name from the path of the file deleted. */ - sqlite3_snprintf(MAXPATHNAME, zDir, "%s", zPath); - zDir[MAXPATHNAME] = '\0'; - for(i=strlen(zDir); i>1 && zDir[i]!='/'; i++); - zDir[i] = '\0'; - - /* Open a file-descriptor on the directory. Sync. Close. */ - dfd = open(zDir, O_RDONLY, 0); - if( dfd<0 ){ - rc = -1; - }else{ - rc = fsync(dfd); - close(dfd); - } - } - return (rc==0 ? SQLITE_OK : SQLITE_IOERR_DELETE); -} - -#ifndef F_OK -# define F_OK 0 -#endif -#ifndef R_OK -# define R_OK 4 -#endif -#ifndef W_OK -# define W_OK 2 -#endif - -/* -** Query the file-system to see if the named file exists, is readable or -** is both readable and writable. -*/ -static int demoAccess( - sqlite3_vfs *pVfs, - const char *zPath, - int flags, - int *pResOut -){ - int rc; /* access() return code */ - int eAccess = F_OK; /* Second argument to access() */ - - assert( flags==SQLITE_ACCESS_EXISTS /* access(zPath, F_OK) */ - || flags==SQLITE_ACCESS_READ /* access(zPath, R_OK) */ - || flags==SQLITE_ACCESS_READWRITE /* access(zPath, R_OK|W_OK) */ - ); - - if( flags==SQLITE_ACCESS_READWRITE ) eAccess = R_OK|W_OK; - if( flags==SQLITE_ACCESS_READ ) eAccess = R_OK; - - rc = access(zPath, eAccess); - *pResOut = (rc==0); - return SQLITE_OK; -} - -/* -** Argument zPath points to a nul-terminated string containing a file path. -** If zPath is an absolute path, then it is copied as is into the output -** buffer. Otherwise, if it is a relative path, then the equivalent full -** path is written to the output buffer. -** -** This function assumes that paths are UNIX style. Specifically, that: -** -** 1. Path components are separated by a '/'. and -** 2. Full paths begin with a '/' character. -*/ -static int demoFullPathname( - sqlite3_vfs *pVfs, /* VFS */ - const char *zPath, /* Input path (possibly a relative path) */ - int nPathOut, /* Size of output buffer in bytes */ - char *zPathOut /* Pointer to output buffer */ -){ - char zDir[MAXPATHNAME+1]; - if( zPath[0]=='/' ){ - zDir[0] = '\0'; - }else{ - if( getcwd(zDir, sizeof(zDir))==0 ) return SQLITE_IOERR; - } - zDir[MAXPATHNAME] = '\0'; - - sqlite3_snprintf(nPathOut, zPathOut, "%s/%s", zDir, zPath); - zPathOut[nPathOut-1] = '\0'; - - return SQLITE_OK; -} - -/* -** The following four VFS methods: -** -** xDlOpen -** xDlError -** xDlSym -** xDlClose -** -** are supposed to implement the functionality needed by SQLite to load -** extensions compiled as shared objects. This simple VFS does not support -** this functionality, so the following functions are no-ops. -*/ -static void *demoDlOpen(sqlite3_vfs *pVfs, const char *zPath){ - return 0; -} -static void demoDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){ - sqlite3_snprintf(nByte, zErrMsg, "Loadable extensions are not supported"); - zErrMsg[nByte-1] = '\0'; -} -static void (*demoDlSym(sqlite3_vfs *pVfs, void *pH, const char *z))(void){ - return 0; -} -static void demoDlClose(sqlite3_vfs *pVfs, void *pHandle){ - return; -} - -/* -** Parameter zByte points to a buffer nByte bytes in size. Populate this -** buffer with pseudo-random data. -*/ -static int demoRandomness(sqlite3_vfs *pVfs, int nByte, char *zByte){ - return SQLITE_OK; -} - -/* -** Sleep for at least nMicro microseconds. Return the (approximate) number -** of microseconds slept for. -*/ -static int demoSleep(sqlite3_vfs *pVfs, int nMicro){ - sleep(nMicro / 1000000); - usleep(nMicro % 1000000); - return nMicro; -} - -/* -** Set *pTime to the current UTC time expressed as a Julian day. Return -** SQLITE_OK if successful, or an error code otherwise. -** -** http://en.wikipedia.org/wiki/Julian_day -** -** This implementation is not very good. The current time is rounded to -** an integer number of seconds. Also, assuming time_t is a signed 32-bit -** value, it will stop working some time in the year 2038 AD (the so-called -** "year 2038" problem that afflicts systems that store time this way). -*/ -static int demoCurrentTime(sqlite3_vfs *pVfs, double *pTime){ - time_t t = time(0); - *pTime = t/86400.0 + 2440587.5; - return SQLITE_OK; -} - -/* -** This function returns a pointer to the VFS implemented in this file. -** To make the VFS available to SQLite: -** -** sqlite3_vfs_register(sqlite3_demovfs(), 0); -*/ -sqlite3_vfs *sqlite3_demovfs(void){ - static sqlite3_vfs demovfs = { - 1, /* iVersion */ - sizeof(DemoFile), /* szOsFile */ - MAXPATHNAME, /* mxPathname */ - 0, /* pNext */ - "demo", /* zName */ - 0, /* pAppData */ - demoOpen, /* xOpen */ - demoDelete, /* xDelete */ - demoAccess, /* xAccess */ - demoFullPathname, /* xFullPathname */ - demoDlOpen, /* xDlOpen */ - demoDlError, /* xDlError */ - demoDlSym, /* xDlSym */ - demoDlClose, /* xDlClose */ - demoRandomness, /* xRandomness */ - demoSleep, /* xSleep */ - demoCurrentTime, /* xCurrentTime */ - }; - return &demovfs; -} - -#endif /* !defined(SQLITE_TEST) || SQLITE_OS_UNIX */ - - -#ifdef SQLITE_TEST - -#include <tcl.h> - -#if SQLITE_OS_UNIX -static int register_demovfs( - ClientData clientData, /* Pointer to sqlite3_enable_XXX function */ - Tcl_Interp *interp, /* The TCL interpreter that invoked this command */ - int objc, /* Number of arguments */ - Tcl_Obj *CONST objv[] /* Command arguments */ -){ - sqlite3_vfs_register(sqlite3_demovfs(), 1); - return TCL_OK; -} -static int unregister_demovfs( - ClientData clientData, /* Pointer to sqlite3_enable_XXX function */ - Tcl_Interp *interp, /* The TCL interpreter that invoked this command */ - int objc, /* Number of arguments */ - Tcl_Obj *CONST objv[] /* Command arguments */ -){ - sqlite3_vfs_unregister(sqlite3_demovfs()); - return TCL_OK; -} - -/* -** Register commands with the TCL interpreter. -*/ -int Sqlitetest_demovfs_Init(Tcl_Interp *interp){ - Tcl_CreateObjCommand(interp, "register_demovfs", register_demovfs, 0, 0); - Tcl_CreateObjCommand(interp, "unregister_demovfs", unregister_demovfs, 0, 0); - return TCL_OK; -} - -#else -int Sqlitetest_demovfs_Init(Tcl_Interp *interp){ return TCL_OK; } -#endif - -#endif /* SQLITE_TEST */ |