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Diffstat (limited to 'src/memdb.c')
| -rw-r--r-- | src/memdb.c | 928 |
1 files changed, 928 insertions, 0 deletions
diff --git a/src/memdb.c b/src/memdb.c new file mode 100644 index 0000000..657cb9c --- /dev/null +++ b/src/memdb.c @@ -0,0 +1,928 @@ +/* +** 2016-09-07 +** +** 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 in-memory VFS. A database is held as a contiguous +** block of memory. +** +** This file also implements interface sqlite3_serialize() and +** sqlite3_deserialize(). +*/ +#include "sqliteInt.h" +#ifndef SQLITE_OMIT_DESERIALIZE + +/* +** Forward declaration of objects used by this utility +*/ +typedef struct sqlite3_vfs MemVfs; +typedef struct MemFile MemFile; +typedef struct MemStore MemStore; + +/* Access to a lower-level VFS that (might) implement dynamic loading, +** access to randomness, etc. +*/ +#define ORIGVFS(p) ((sqlite3_vfs*)((p)->pAppData)) + +/* Storage for a memdb file. +** +** An memdb object can be shared or separate. Shared memdb objects can be +** used by more than one database connection. Mutexes are used by shared +** memdb objects to coordinate access. Separate memdb objects are only +** connected to a single database connection and do not require additional +** mutexes. +** +** Shared memdb objects have .zFName!=0 and .pMutex!=0. They are created +** using "file:/name?vfs=memdb". The first character of the name must be +** "/" or else the object will be a separate memdb object. All shared +** memdb objects are stored in memdb_g.apMemStore[] in an arbitrary order. +** +** Separate memdb objects are created using a name that does not begin +** with "/" or using sqlite3_deserialize(). +** +** Access rules for shared MemStore objects: +** +** * .zFName is initialized when the object is created and afterwards +** is unchanged until the object is destroyed. So it can be accessed +** at any time as long as we know the object is not being destroyed, +** which means while either the SQLITE_MUTEX_STATIC_VFS1 or +** .pMutex is held or the object is not part of memdb_g.apMemStore[]. +** +** * Can .pMutex can only be changed while holding the +** SQLITE_MUTEX_STATIC_VFS1 mutex or while the object is not part +** of memdb_g.apMemStore[]. +** +** * Other fields can only be changed while holding the .pMutex mutex +** or when the .nRef is less than zero and the object is not part of +** memdb_g.apMemStore[]. +** +** * The .aData pointer has the added requirement that it can can only +** be changed (for resizing) when nMmap is zero. +** +*/ +struct MemStore { + sqlite3_int64 sz; /* Size of the file */ + sqlite3_int64 szAlloc; /* Space allocated to aData */ + sqlite3_int64 szMax; /* Maximum allowed size of the file */ + unsigned char *aData; /* content of the file */ + sqlite3_mutex *pMutex; /* Used by shared stores only */ + int nMmap; /* Number of memory mapped pages */ + unsigned mFlags; /* Flags */ + int nRdLock; /* Number of readers */ + int nWrLock; /* Number of writers. (Always 0 or 1) */ + int nRef; /* Number of users of this MemStore */ + char *zFName; /* The filename for shared stores */ +}; + +/* An open file */ +struct MemFile { + sqlite3_file base; /* IO methods */ + MemStore *pStore; /* The storage */ + int eLock; /* Most recent lock against this file */ +}; + +/* +** File-scope variables for holding the memdb files that are accessible +** to multiple database connections in separate threads. +** +** Must hold SQLITE_MUTEX_STATIC_VFS1 to access any part of this object. +*/ +static struct MemFS { + int nMemStore; /* Number of shared MemStore objects */ + MemStore **apMemStore; /* Array of all shared MemStore objects */ +} memdb_g; + +/* +** Methods for MemFile +*/ +static int memdbClose(sqlite3_file*); +static int memdbRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst); +static int memdbWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst); +static int memdbTruncate(sqlite3_file*, sqlite3_int64 size); +static int memdbSync(sqlite3_file*, int flags); +static int memdbFileSize(sqlite3_file*, sqlite3_int64 *pSize); +static int memdbLock(sqlite3_file*, int); +static int memdbUnlock(sqlite3_file*, int); +/* static int memdbCheckReservedLock(sqlite3_file*, int *pResOut);// not used */ +static int memdbFileControl(sqlite3_file*, int op, void *pArg); +/* static int memdbSectorSize(sqlite3_file*); // not used */ +static int memdbDeviceCharacteristics(sqlite3_file*); +static int memdbFetch(sqlite3_file*, sqlite3_int64 iOfst, int iAmt, void **pp); +static int memdbUnfetch(sqlite3_file*, sqlite3_int64 iOfst, void *p); + +/* +** Methods for MemVfs +*/ +static int memdbOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *); +/* static int memdbDelete(sqlite3_vfs*, const char *zName, int syncDir); */ +static int memdbAccess(sqlite3_vfs*, const char *zName, int flags, int *); +static int memdbFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut); +static void *memdbDlOpen(sqlite3_vfs*, const char *zFilename); +static void memdbDlError(sqlite3_vfs*, int nByte, char *zErrMsg); +static void (*memdbDlSym(sqlite3_vfs *pVfs, void *p, const char*zSym))(void); +static void memdbDlClose(sqlite3_vfs*, void*); +static int memdbRandomness(sqlite3_vfs*, int nByte, char *zOut); +static int memdbSleep(sqlite3_vfs*, int microseconds); +/* static int memdbCurrentTime(sqlite3_vfs*, double*); */ +static int memdbGetLastError(sqlite3_vfs*, int, char *); +static int memdbCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*); + +static sqlite3_vfs memdb_vfs = { + 2, /* iVersion */ + 0, /* szOsFile (set when registered) */ + 1024, /* mxPathname */ + 0, /* pNext */ + "memdb", /* zName */ + 0, /* pAppData (set when registered) */ + memdbOpen, /* xOpen */ + 0, /* memdbDelete, */ /* xDelete */ + memdbAccess, /* xAccess */ + memdbFullPathname, /* xFullPathname */ + memdbDlOpen, /* xDlOpen */ + memdbDlError, /* xDlError */ + memdbDlSym, /* xDlSym */ + memdbDlClose, /* xDlClose */ + memdbRandomness, /* xRandomness */ + memdbSleep, /* xSleep */ + 0, /* memdbCurrentTime, */ /* xCurrentTime */ + memdbGetLastError, /* xGetLastError */ + memdbCurrentTimeInt64, /* xCurrentTimeInt64 */ + 0, /* xSetSystemCall */ + 0, /* xGetSystemCall */ + 0, /* xNextSystemCall */ +}; + +static const sqlite3_io_methods memdb_io_methods = { + 3, /* iVersion */ + memdbClose, /* xClose */ + memdbRead, /* xRead */ + memdbWrite, /* xWrite */ + memdbTruncate, /* xTruncate */ + memdbSync, /* xSync */ + memdbFileSize, /* xFileSize */ + memdbLock, /* xLock */ + memdbUnlock, /* xUnlock */ + 0, /* memdbCheckReservedLock, */ /* xCheckReservedLock */ + memdbFileControl, /* xFileControl */ + 0, /* memdbSectorSize,*/ /* xSectorSize */ + memdbDeviceCharacteristics, /* xDeviceCharacteristics */ + 0, /* xShmMap */ + 0, /* xShmLock */ + 0, /* xShmBarrier */ + 0, /* xShmUnmap */ + memdbFetch, /* xFetch */ + memdbUnfetch /* xUnfetch */ +}; + +/* +** Enter/leave the mutex on a MemStore +*/ +#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE==0 +static void memdbEnter(MemStore *p){ + UNUSED_PARAMETER(p); +} +static void memdbLeave(MemStore *p){ + UNUSED_PARAMETER(p); +} +#else +static void memdbEnter(MemStore *p){ + sqlite3_mutex_enter(p->pMutex); +} +static void memdbLeave(MemStore *p){ + sqlite3_mutex_leave(p->pMutex); +} +#endif + + + +/* +** Close an memdb-file. +** Free the underlying MemStore object when its refcount drops to zero +** or less. +*/ +static int memdbClose(sqlite3_file *pFile){ + MemStore *p = ((MemFile*)pFile)->pStore; + if( p->zFName ){ + int i; +#ifndef SQLITE_MUTEX_OMIT + sqlite3_mutex *pVfsMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1); +#endif + sqlite3_mutex_enter(pVfsMutex); + for(i=0; ALWAYS(i<memdb_g.nMemStore); i++){ + if( memdb_g.apMemStore[i]==p ){ + memdbEnter(p); + if( p->nRef==1 ){ + memdb_g.apMemStore[i] = memdb_g.apMemStore[--memdb_g.nMemStore]; + if( memdb_g.nMemStore==0 ){ + sqlite3_free(memdb_g.apMemStore); + memdb_g.apMemStore = 0; + } + } + break; + } + } + sqlite3_mutex_leave(pVfsMutex); + }else{ + memdbEnter(p); + } + p->nRef--; + if( p->nRef<=0 ){ + if( p->mFlags & SQLITE_DESERIALIZE_FREEONCLOSE ){ + sqlite3_free(p->aData); + } + memdbLeave(p); + sqlite3_mutex_free(p->pMutex); + sqlite3_free(p); + }else{ + memdbLeave(p); + } + return SQLITE_OK; +} + +/* +** Read data from an memdb-file. +*/ +static int memdbRead( + sqlite3_file *pFile, + void *zBuf, + int iAmt, + sqlite_int64 iOfst +){ + MemStore *p = ((MemFile*)pFile)->pStore; + memdbEnter(p); + if( iOfst+iAmt>p->sz ){ + memset(zBuf, 0, iAmt); + if( iOfst<p->sz ) memcpy(zBuf, p->aData+iOfst, p->sz - iOfst); + memdbLeave(p); + return SQLITE_IOERR_SHORT_READ; + } + memcpy(zBuf, p->aData+iOfst, iAmt); + memdbLeave(p); + return SQLITE_OK; +} + +/* +** Try to enlarge the memory allocation to hold at least sz bytes +*/ +static int memdbEnlarge(MemStore *p, sqlite3_int64 newSz){ + unsigned char *pNew; + if( (p->mFlags & SQLITE_DESERIALIZE_RESIZEABLE)==0 || NEVER(p->nMmap>0) ){ + return SQLITE_FULL; + } + if( newSz>p->szMax ){ + return SQLITE_FULL; + } + newSz *= 2; + if( newSz>p->szMax ) newSz = p->szMax; + pNew = sqlite3Realloc(p->aData, newSz); + if( pNew==0 ) return SQLITE_IOERR_NOMEM; + p->aData = pNew; + p->szAlloc = newSz; + return SQLITE_OK; +} + +/* +** Write data to an memdb-file. +*/ +static int memdbWrite( + sqlite3_file *pFile, + const void *z, + int iAmt, + sqlite_int64 iOfst +){ + MemStore *p = ((MemFile*)pFile)->pStore; + memdbEnter(p); + if( NEVER(p->mFlags & SQLITE_DESERIALIZE_READONLY) ){ + /* Can't happen: memdbLock() will return SQLITE_READONLY before + ** reaching this point */ + memdbLeave(p); + return SQLITE_IOERR_WRITE; + } + if( iOfst+iAmt>p->sz ){ + int rc; + if( iOfst+iAmt>p->szAlloc + && (rc = memdbEnlarge(p, iOfst+iAmt))!=SQLITE_OK + ){ + memdbLeave(p); + return rc; + } + if( iOfst>p->sz ) memset(p->aData+p->sz, 0, iOfst-p->sz); + p->sz = iOfst+iAmt; + } + memcpy(p->aData+iOfst, z, iAmt); + memdbLeave(p); + return SQLITE_OK; +} + +/* +** Truncate an memdb-file. +** +** In rollback mode (which is always the case for memdb, as it does not +** support WAL mode) the truncate() method is only used to reduce +** the size of a file, never to increase the size. +*/ +static int memdbTruncate(sqlite3_file *pFile, sqlite_int64 size){ + MemStore *p = ((MemFile*)pFile)->pStore; + int rc = SQLITE_OK; + memdbEnter(p); + if( size>p->sz ){ + /* This can only happen with a corrupt wal mode db */ + rc = SQLITE_CORRUPT; + }else{ + p->sz = size; + } + memdbLeave(p); + return rc; +} + +/* +** Sync an memdb-file. +*/ +static int memdbSync(sqlite3_file *pFile, int flags){ + UNUSED_PARAMETER(pFile); + UNUSED_PARAMETER(flags); + return SQLITE_OK; +} + +/* +** Return the current file-size of an memdb-file. +*/ +static int memdbFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){ + MemStore *p = ((MemFile*)pFile)->pStore; + memdbEnter(p); + *pSize = p->sz; + memdbLeave(p); + return SQLITE_OK; +} + +/* +** Lock an memdb-file. +*/ +static int memdbLock(sqlite3_file *pFile, int eLock){ + MemFile *pThis = (MemFile*)pFile; + MemStore *p = pThis->pStore; + int rc = SQLITE_OK; + if( eLock<=pThis->eLock ) return SQLITE_OK; + memdbEnter(p); + + assert( p->nWrLock==0 || p->nWrLock==1 ); + assert( pThis->eLock<=SQLITE_LOCK_SHARED || p->nWrLock==1 ); + assert( pThis->eLock==SQLITE_LOCK_NONE || p->nRdLock>=1 ); + + if( eLock>SQLITE_LOCK_SHARED && (p->mFlags & SQLITE_DESERIALIZE_READONLY) ){ + rc = SQLITE_READONLY; + }else{ + switch( eLock ){ + case SQLITE_LOCK_SHARED: { + assert( pThis->eLock==SQLITE_LOCK_NONE ); + if( p->nWrLock>0 ){ + rc = SQLITE_BUSY; + }else{ + p->nRdLock++; + } + break; + }; + + case SQLITE_LOCK_RESERVED: + case SQLITE_LOCK_PENDING: { + assert( pThis->eLock>=SQLITE_LOCK_SHARED ); + if( ALWAYS(pThis->eLock==SQLITE_LOCK_SHARED) ){ + if( p->nWrLock>0 ){ + rc = SQLITE_BUSY; + }else{ + p->nWrLock = 1; + } + } + break; + } + + default: { + assert( eLock==SQLITE_LOCK_EXCLUSIVE ); + assert( pThis->eLock>=SQLITE_LOCK_SHARED ); + if( p->nRdLock>1 ){ + rc = SQLITE_BUSY; + }else if( pThis->eLock==SQLITE_LOCK_SHARED ){ + p->nWrLock = 1; + } + break; + } + } + } + if( rc==SQLITE_OK ) pThis->eLock = eLock; + memdbLeave(p); + return rc; +} + +/* +** Unlock an memdb-file. +*/ +static int memdbUnlock(sqlite3_file *pFile, int eLock){ + MemFile *pThis = (MemFile*)pFile; + MemStore *p = pThis->pStore; + if( eLock>=pThis->eLock ) return SQLITE_OK; + memdbEnter(p); + + assert( eLock==SQLITE_LOCK_SHARED || eLock==SQLITE_LOCK_NONE ); + if( eLock==SQLITE_LOCK_SHARED ){ + if( ALWAYS(pThis->eLock>SQLITE_LOCK_SHARED) ){ + p->nWrLock--; + } + }else{ + if( pThis->eLock>SQLITE_LOCK_SHARED ){ + p->nWrLock--; + } + p->nRdLock--; + } + + pThis->eLock = eLock; + memdbLeave(p); + return SQLITE_OK; +} + +#if 0 +/* +** This interface is only used for crash recovery, which does not +** occur on an in-memory database. +*/ +static int memdbCheckReservedLock(sqlite3_file *pFile, int *pResOut){ + *pResOut = 0; + return SQLITE_OK; +} +#endif + + +/* +** File control method. For custom operations on an memdb-file. +*/ +static int memdbFileControl(sqlite3_file *pFile, int op, void *pArg){ + MemStore *p = ((MemFile*)pFile)->pStore; + int rc = SQLITE_NOTFOUND; + memdbEnter(p); + if( op==SQLITE_FCNTL_VFSNAME ){ + *(char**)pArg = sqlite3_mprintf("memdb(%p,%lld)", p->aData, p->sz); + rc = SQLITE_OK; + } + if( op==SQLITE_FCNTL_SIZE_LIMIT ){ + sqlite3_int64 iLimit = *(sqlite3_int64*)pArg; + if( iLimit<p->sz ){ + if( iLimit<0 ){ + iLimit = p->szMax; + }else{ + iLimit = p->sz; + } + } + p->szMax = iLimit; + *(sqlite3_int64*)pArg = iLimit; + rc = SQLITE_OK; + } + memdbLeave(p); + return rc; +} + +#if 0 /* Not used because of SQLITE_IOCAP_POWERSAFE_OVERWRITE */ +/* +** Return the sector-size in bytes for an memdb-file. +*/ +static int memdbSectorSize(sqlite3_file *pFile){ + return 1024; +} +#endif + +/* +** Return the device characteristic flags supported by an memdb-file. +*/ +static int memdbDeviceCharacteristics(sqlite3_file *pFile){ + UNUSED_PARAMETER(pFile); + return SQLITE_IOCAP_ATOMIC | + SQLITE_IOCAP_POWERSAFE_OVERWRITE | + SQLITE_IOCAP_SAFE_APPEND | + SQLITE_IOCAP_SEQUENTIAL; +} + +/* Fetch a page of a memory-mapped file */ +static int memdbFetch( + sqlite3_file *pFile, + sqlite3_int64 iOfst, + int iAmt, + void **pp +){ + MemStore *p = ((MemFile*)pFile)->pStore; + memdbEnter(p); + if( iOfst+iAmt>p->sz || (p->mFlags & SQLITE_DESERIALIZE_RESIZEABLE)!=0 ){ + *pp = 0; + }else{ + p->nMmap++; + *pp = (void*)(p->aData + iOfst); + } + memdbLeave(p); + return SQLITE_OK; +} + +/* Release a memory-mapped page */ +static int memdbUnfetch(sqlite3_file *pFile, sqlite3_int64 iOfst, void *pPage){ + MemStore *p = ((MemFile*)pFile)->pStore; + UNUSED_PARAMETER(iOfst); + UNUSED_PARAMETER(pPage); + memdbEnter(p); + p->nMmap--; + memdbLeave(p); + return SQLITE_OK; +} + +/* +** Open an mem file handle. +*/ +static int memdbOpen( + sqlite3_vfs *pVfs, + const char *zName, + sqlite3_file *pFd, + int flags, + int *pOutFlags +){ + MemFile *pFile = (MemFile*)pFd; + MemStore *p = 0; + int szName; + UNUSED_PARAMETER(pVfs); + + memset(pFile, 0, sizeof(*pFile)); + szName = sqlite3Strlen30(zName); + if( szName>1 && (zName[0]=='/' || zName[0]=='\\') ){ + int i; +#ifndef SQLITE_MUTEX_OMIT + sqlite3_mutex *pVfsMutex = sqlite3MutexAlloc(SQLITE_MUTEX_STATIC_VFS1); +#endif + sqlite3_mutex_enter(pVfsMutex); + for(i=0; i<memdb_g.nMemStore; i++){ + if( strcmp(memdb_g.apMemStore[i]->zFName,zName)==0 ){ + p = memdb_g.apMemStore[i]; + break; + } + } + if( p==0 ){ + MemStore **apNew; + p = sqlite3Malloc( sizeof(*p) + szName + 3 ); + if( p==0 ){ + sqlite3_mutex_leave(pVfsMutex); + return SQLITE_NOMEM; + } + apNew = sqlite3Realloc(memdb_g.apMemStore, + sizeof(apNew[0])*(memdb_g.nMemStore+1) ); + if( apNew==0 ){ + sqlite3_free(p); + sqlite3_mutex_leave(pVfsMutex); + return SQLITE_NOMEM; + } + apNew[memdb_g.nMemStore++] = p; + memdb_g.apMemStore = apNew; + memset(p, 0, sizeof(*p)); + p->mFlags = SQLITE_DESERIALIZE_RESIZEABLE|SQLITE_DESERIALIZE_FREEONCLOSE; + p->szMax = sqlite3GlobalConfig.mxMemdbSize; + p->zFName = (char*)&p[1]; + memcpy(p->zFName, zName, szName+1); + p->pMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST); + if( p->pMutex==0 ){ + memdb_g.nMemStore--; + sqlite3_free(p); + sqlite3_mutex_leave(pVfsMutex); + return SQLITE_NOMEM; + } + p->nRef = 1; + memdbEnter(p); + }else{ + memdbEnter(p); + p->nRef++; + } + sqlite3_mutex_leave(pVfsMutex); + }else{ + p = sqlite3Malloc( sizeof(*p) ); + if( p==0 ){ + return SQLITE_NOMEM; + } + memset(p, 0, sizeof(*p)); + p->mFlags = SQLITE_DESERIALIZE_RESIZEABLE | SQLITE_DESERIALIZE_FREEONCLOSE; + p->szMax = sqlite3GlobalConfig.mxMemdbSize; + } + pFile->pStore = p; + if( pOutFlags!=0 ){ + *pOutFlags = flags | SQLITE_OPEN_MEMORY; + } + pFd->pMethods = &memdb_io_methods; + memdbLeave(p); + return SQLITE_OK; +} + +#if 0 /* Only used to delete rollback journals, super-journals, and WAL + ** files, none of which exist in memdb. So this routine is never used */ +/* +** Delete the file located at zPath. If the dirSync argument is true, +** ensure the file-system modifications are synced to disk before +** returning. +*/ +static int memdbDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){ + return SQLITE_IOERR_DELETE; +} +#endif + +/* +** Test for access permissions. Return true if the requested permission +** is available, or false otherwise. +** +** With memdb, no files ever exist on disk. So always return false. +*/ +static int memdbAccess( + sqlite3_vfs *pVfs, + const char *zPath, + int flags, + int *pResOut +){ + UNUSED_PARAMETER(pVfs); + UNUSED_PARAMETER(zPath); + UNUSED_PARAMETER(flags); + *pResOut = 0; + return SQLITE_OK; +} + +/* +** Populate buffer zOut with the full canonical pathname corresponding +** to the pathname in zPath. zOut is guaranteed to point to a buffer +** of at least (INST_MAX_PATHNAME+1) bytes. +*/ +static int memdbFullPathname( + sqlite3_vfs *pVfs, + const char *zPath, + int nOut, + char *zOut +){ + UNUSED_PARAMETER(pVfs); + sqlite3_snprintf(nOut, zOut, "%s", zPath); + return SQLITE_OK; +} + +/* +** Open the dynamic library located at zPath and return a handle. +*/ +static void *memdbDlOpen(sqlite3_vfs *pVfs, const char *zPath){ + return ORIGVFS(pVfs)->xDlOpen(ORIGVFS(pVfs), zPath); +} + +/* +** Populate the buffer zErrMsg (size nByte bytes) with a human readable +** utf-8 string describing the most recent error encountered associated +** with dynamic libraries. +*/ +static void memdbDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){ + ORIGVFS(pVfs)->xDlError(ORIGVFS(pVfs), nByte, zErrMsg); +} + +/* +** Return a pointer to the symbol zSymbol in the dynamic library pHandle. +*/ +static void (*memdbDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){ + return ORIGVFS(pVfs)->xDlSym(ORIGVFS(pVfs), p, zSym); +} + +/* +** Close the dynamic library handle pHandle. +*/ +static void memdbDlClose(sqlite3_vfs *pVfs, void *pHandle){ + ORIGVFS(pVfs)->xDlClose(ORIGVFS(pVfs), pHandle); +} + +/* +** Populate the buffer pointed to by zBufOut with nByte bytes of +** random data. +*/ +static int memdbRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){ + return ORIGVFS(pVfs)->xRandomness(ORIGVFS(pVfs), nByte, zBufOut); +} + +/* +** Sleep for nMicro microseconds. Return the number of microseconds +** actually slept. +*/ +static int memdbSleep(sqlite3_vfs *pVfs, int nMicro){ + return ORIGVFS(pVfs)->xSleep(ORIGVFS(pVfs), nMicro); +} + +#if 0 /* Never used. Modern cores only call xCurrentTimeInt64() */ +/* +** Return the current time as a Julian Day number in *pTimeOut. +*/ +static int memdbCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){ + return ORIGVFS(pVfs)->xCurrentTime(ORIGVFS(pVfs), pTimeOut); +} +#endif + +static int memdbGetLastError(sqlite3_vfs *pVfs, int a, char *b){ + return ORIGVFS(pVfs)->xGetLastError(ORIGVFS(pVfs), a, b); +} +static int memdbCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *p){ + return ORIGVFS(pVfs)->xCurrentTimeInt64(ORIGVFS(pVfs), p); +} + +/* +** Translate a database connection pointer and schema name into a +** MemFile pointer. +*/ +static MemFile *memdbFromDbSchema(sqlite3 *db, const char *zSchema){ + MemFile *p = 0; + MemStore *pStore; + int rc = sqlite3_file_control(db, zSchema, SQLITE_FCNTL_FILE_POINTER, &p); + if( rc ) return 0; + if( p->base.pMethods!=&memdb_io_methods ) return 0; + pStore = p->pStore; + memdbEnter(pStore); + if( pStore->zFName!=0 ) p = 0; + memdbLeave(pStore); + return p; +} + +/* +** Return the serialization of a database +*/ +unsigned char *sqlite3_serialize( + sqlite3 *db, /* The database connection */ + const char *zSchema, /* Which database within the connection */ + sqlite3_int64 *piSize, /* Write size here, if not NULL */ + unsigned int mFlags /* Maybe SQLITE_SERIALIZE_NOCOPY */ +){ + MemFile *p; + int iDb; + Btree *pBt; + sqlite3_int64 sz; + int szPage = 0; + sqlite3_stmt *pStmt = 0; + unsigned char *pOut; + char *zSql; + int rc; + +#ifdef SQLITE_ENABLE_API_ARMOR + if( !sqlite3SafetyCheckOk(db) ){ + (void)SQLITE_MISUSE_BKPT; + return 0; + } +#endif + + if( zSchema==0 ) zSchema = db->aDb[0].zDbSName; + p = memdbFromDbSchema(db, zSchema); + iDb = sqlite3FindDbName(db, zSchema); + if( piSize ) *piSize = -1; + if( iDb<0 ) return 0; + if( p ){ + MemStore *pStore = p->pStore; + assert( pStore->pMutex==0 ); + if( piSize ) *piSize = pStore->sz; + if( mFlags & SQLITE_SERIALIZE_NOCOPY ){ + pOut = pStore->aData; + }else{ + pOut = sqlite3_malloc64( pStore->sz ); + if( pOut ) memcpy(pOut, pStore->aData, pStore->sz); + } + return pOut; + } + pBt = db->aDb[iDb].pBt; + if( pBt==0 ) return 0; + szPage = sqlite3BtreeGetPageSize(pBt); + zSql = sqlite3_mprintf("PRAGMA \"%w\".page_count", zSchema); + rc = zSql ? sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0) : SQLITE_NOMEM; + sqlite3_free(zSql); + if( rc ) return 0; + rc = sqlite3_step(pStmt); + if( rc!=SQLITE_ROW ){ + pOut = 0; + }else{ + sz = sqlite3_column_int64(pStmt, 0)*szPage; + if( piSize ) *piSize = sz; + if( mFlags & SQLITE_SERIALIZE_NOCOPY ){ + pOut = 0; + }else{ + pOut = sqlite3_malloc64( sz ); + if( pOut ){ + int nPage = sqlite3_column_int(pStmt, 0); + Pager *pPager = sqlite3BtreePager(pBt); + int pgno; + for(pgno=1; pgno<=nPage; pgno++){ + DbPage *pPage = 0; + unsigned char *pTo = pOut + szPage*(sqlite3_int64)(pgno-1); + rc = sqlite3PagerGet(pPager, pgno, (DbPage**)&pPage, 0); + if( rc==SQLITE_OK ){ + memcpy(pTo, sqlite3PagerGetData(pPage), szPage); + }else{ + memset(pTo, 0, szPage); + } + sqlite3PagerUnref(pPage); + } + } + } + } + sqlite3_finalize(pStmt); + return pOut; +} + +/* Convert zSchema to a MemDB and initialize its content. +*/ +int sqlite3_deserialize( + sqlite3 *db, /* The database connection */ + const char *zSchema, /* Which DB to reopen with the deserialization */ + unsigned char *pData, /* The serialized database content */ + sqlite3_int64 szDb, /* Number bytes in the deserialization */ + sqlite3_int64 szBuf, /* Total size of buffer pData[] */ + unsigned mFlags /* Zero or more SQLITE_DESERIALIZE_* flags */ +){ + MemFile *p; + char *zSql; + sqlite3_stmt *pStmt = 0; + int rc; + int iDb; + +#ifdef SQLITE_ENABLE_API_ARMOR + if( !sqlite3SafetyCheckOk(db) ){ + return SQLITE_MISUSE_BKPT; + } + if( szDb<0 ) return SQLITE_MISUSE_BKPT; + if( szBuf<0 ) return SQLITE_MISUSE_BKPT; +#endif + + sqlite3_mutex_enter(db->mutex); + if( zSchema==0 ) zSchema = db->aDb[0].zDbSName; + iDb = sqlite3FindDbName(db, zSchema); + testcase( iDb==1 ); + if( iDb<2 && iDb!=0 ){ + rc = SQLITE_ERROR; + goto end_deserialize; + } + zSql = sqlite3_mprintf("ATTACH x AS %Q", zSchema); + if( zSql==0 ){ + rc = SQLITE_NOMEM; + }else{ + rc = sqlite3_prepare_v2(db, zSql, -1, &pStmt, 0); + sqlite3_free(zSql); + } + if( rc ) goto end_deserialize; + db->init.iDb = (u8)iDb; + db->init.reopenMemdb = 1; + rc = sqlite3_step(pStmt); + db->init.reopenMemdb = 0; + if( rc!=SQLITE_DONE ){ + rc = SQLITE_ERROR; + goto end_deserialize; + } + p = memdbFromDbSchema(db, zSchema); + if( p==0 ){ + rc = SQLITE_ERROR; + }else{ + MemStore *pStore = p->pStore; + pStore->aData = pData; + pData = 0; + pStore->sz = szDb; + pStore->szAlloc = szBuf; + pStore->szMax = szBuf; + if( pStore->szMax<sqlite3GlobalConfig.mxMemdbSize ){ + pStore->szMax = sqlite3GlobalConfig.mxMemdbSize; + } + pStore->mFlags = mFlags; + rc = SQLITE_OK; + } + +end_deserialize: + sqlite3_finalize(pStmt); + if( pData && (mFlags & SQLITE_DESERIALIZE_FREEONCLOSE)!=0 ){ + sqlite3_free(pData); + } + sqlite3_mutex_leave(db->mutex); + return rc; +} + +/* +** Return true if the VFS is the memvfs. +*/ +int sqlite3IsMemdb(const sqlite3_vfs *pVfs){ + return pVfs==&memdb_vfs; +} + +/* +** This routine is called when the extension is loaded. +** Register the new VFS. +*/ +int sqlite3MemdbInit(void){ + sqlite3_vfs *pLower = sqlite3_vfs_find(0); + unsigned int sz; + if( NEVER(pLower==0) ) return SQLITE_ERROR; + sz = pLower->szOsFile; + memdb_vfs.pAppData = pLower; + /* The following conditional can only be true when compiled for + ** Windows x86 and SQLITE_MAX_MMAP_SIZE=0. We always leave + ** it in, to be safe, but it is marked as NO_TEST since there + ** is no way to reach it under most builds. */ + if( sz<sizeof(MemFile) ) sz = sizeof(MemFile); /*NO_TEST*/ + memdb_vfs.szOsFile = sz; + return sqlite3_vfs_register(&memdb_vfs, 0); +} +#endif /* SQLITE_OMIT_DESERIALIZE */ |