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Overview
Comment: | Add the memjournal.c file that should have been with the previous checkin. (CVS 5831) |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
0509eff0e6b5cdeeb52c12c0574ea63e |
User & Date: | danielk1977 2008-10-17 19:13:05.000 |
Context
2008-10-19
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21:03 | When a name in double quotes falls back to being a string literal, make sure it has no affinity. Ticket #3442. (CVS 5832) (check-in: 81cfee5c14 user: drh tags: trunk) | |
2008-10-17
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19:13 | Add the memjournal.c file that should have been with the previous checkin. (CVS 5831) (check-in: 0509eff0e6 user: danielk1977 tags: trunk) | |
18:51 | Add "pragma journal_mode=memory". Change the way rollback works for in-memory databases so that it reuses the journal_mode=memory code. (CVS 5830) (check-in: 39ebf01add user: danielk1977 tags: trunk) | |
Changes
Added src/memjournal.c.
> > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 | /* ** 2007 August 22 ** ** 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. ** ************************************************************************* ** ** @(#) $Id: memjournal.c,v 1.1 2008/10/17 19:13:05 danielk1977 Exp $ */ #include "sqliteInt.h" typedef struct MemJournal MemJournal; typedef struct FilePoint FilePoint; typedef struct FileChunk FileChunk; #define JOURNAL_CHUNKSIZE 1024 #define MIN(x,y) ((x)<(y)?(x):(y)) struct FileChunk { FileChunk *pNext; u8 zChunk[JOURNAL_CHUNKSIZE]; }; struct FilePoint { sqlite3_int64 iOffset; FileChunk *pChunk; }; struct MemJournal { sqlite3_io_methods *pMethod; /* I/O methods on journal files */ FileChunk *pFirst; /* Head of in-memory chunk-list */ FilePoint endpoint; /* Pointer to the end of the file */ FilePoint readpoint; /* Pointer to the end of the last xRead() */ }; /* ** Read data from the file. */ static int memjrnlRead( sqlite3_file *pJfd, /* The journal file from which to read */ void *zBuf, /* Put the results here */ int iAmt, /* Number of bytes to read */ sqlite_int64 iOfst /* Begin reading at this offset */ ){ MemJournal *p = (MemJournal *)pJfd; u8 *zOut = zBuf; int nRead = iAmt; int iChunkOffset; FileChunk *pChunk; assert( iOfst+iAmt<=p->endpoint.iOffset ); if( p->readpoint.iOffset!=iOfst || iOfst==0 ){ sqlite3_int64 iOff = 0; for(pChunk=p->pFirst; pChunk && (iOff+JOURNAL_CHUNKSIZE)<=iOfst; pChunk=pChunk->pNext ){ iOff += JOURNAL_CHUNKSIZE; } }else{ pChunk = p->readpoint.pChunk; } iChunkOffset = (iOfst%JOURNAL_CHUNKSIZE); do { int iSpace = JOURNAL_CHUNKSIZE - iChunkOffset; int nCopy = MIN(nRead, (JOURNAL_CHUNKSIZE - iChunkOffset)); memcpy(zOut, &pChunk->zChunk[iChunkOffset], nCopy); zOut += nCopy; nRead -= iSpace; iChunkOffset = 0; } while( nRead>=0 && (pChunk=pChunk->pNext) && nRead>0 ); p->readpoint.iOffset = iOfst+iAmt; p->readpoint.pChunk = pChunk; return SQLITE_OK; } /* ** Write data to the file. */ static int memjrnlWrite( sqlite3_file *pJfd, /* The journal file into which to write */ const void *zBuf, /* Take data to be written from here */ int iAmt, /* Number of bytes to write */ sqlite_int64 iOfst /* Begin writing at this offset into the file */ ){ MemJournal *p = (MemJournal *)pJfd; int nWrite = iAmt; u8 *zWrite = (u8 *)zBuf; /* An in-memory journal file should only ever be appended to. Random ** access writes are not required by sqlite. */ assert(iOfst==p->endpoint.iOffset); while( nWrite>0 ){ FileChunk *pChunk = p->endpoint.pChunk; int iChunkOffset = p->endpoint.iOffset%JOURNAL_CHUNKSIZE; int iSpace = MIN(nWrite, JOURNAL_CHUNKSIZE - iChunkOffset); if( iChunkOffset==0 ){ /* New chunk is required to extend the file. */ FileChunk *pNew = sqlite3_malloc(sizeof(FileChunk)); if( !pNew ){ return SQLITE_IOERR_NOMEM; } pNew->pNext = 0; if( pChunk ){ assert( p->pFirst ); pChunk->pNext = pNew; }else{ assert( !p->pFirst ); p->pFirst = pNew; } p->endpoint.pChunk = pNew; } memcpy(&p->endpoint.pChunk->zChunk[iChunkOffset], zWrite, iSpace); zWrite += iSpace; nWrite -= iSpace; p->endpoint.iOffset += iSpace; } return SQLITE_OK; } /* ** Truncate the file. */ static int memjrnlTruncate(sqlite3_file *pJfd, sqlite_int64 size){ MemJournal *p = (MemJournal *)pJfd; FileChunk *pChunk; assert(size==0); pChunk = p->pFirst; while( pChunk ){ FileChunk *pTmp = pChunk; pChunk = pChunk->pNext; sqlite3_free(pTmp); } sqlite3MemJournalOpen(pJfd); return SQLITE_OK; } /* ** Close the file. */ static int memjrnlClose(sqlite3_file *pJfd){ memjrnlTruncate(pJfd, 0); return SQLITE_OK; } /* ** Sync the file. */ static int memjrnlSync(sqlite3_file *pJfd, int flags){ return SQLITE_OK; } /* ** Query the size of the file in bytes. */ static int memjrnlFileSize(sqlite3_file *pJfd, sqlite_int64 *pSize){ MemJournal *p = (MemJournal *)pJfd; *pSize = (sqlite_int64) p->endpoint.iOffset; return SQLITE_OK; } /* ** Table of methods for MemJournal sqlite3_file object. */ static struct sqlite3_io_methods MemJournalMethods = { 1, /* iVersion */ memjrnlClose, /* xClose */ memjrnlRead, /* xRead */ memjrnlWrite, /* xWrite */ memjrnlTruncate, /* xTruncate */ memjrnlSync, /* xSync */ memjrnlFileSize, /* xFileSize */ 0, /* xLock */ 0, /* xUnlock */ 0, /* xCheckReservedLock */ 0, /* xFileControl */ 0, /* xSectorSize */ 0 /* xDeviceCharacteristics */ }; /* ** Open a journal file. */ void sqlite3MemJournalOpen(sqlite3_file *pJfd){ MemJournal *p = (MemJournal *)pJfd; memset(p, 0, sqlite3MemJournalSize()); p->pMethod = &MemJournalMethods; } /* ** Return true if the file-handle passed as an argument is ** an in-memory journal */ int sqlite3IsMemJournal(sqlite3_file *pJfd){ return pJfd->pMethods==&MemJournalMethods; } /* ** Return the number of bytes required to store a MemJournal that uses vfs ** pVfs to create the underlying on-disk files. */ int sqlite3MemJournalSize(){ return sizeof(MemJournal); } |