1 /* 2 ** 2001 September 15 3 ** 4 ** The author disclaims copyright to this source code. In place of 5 ** a legal notice, here is a blessing: 6 ** 7 ** May you do good and not evil. 8 ** May you find forgiveness for yourself and forgive others. 9 ** May you share freely, never taking more than you give. 10 ** 11 ************************************************************************* 12 ** This header file defines the interface that the sqlite B-Tree file 13 ** subsystem. See comments in the source code for a detailed description 14 ** of what each interface routine does. 15 */ 16 #ifndef SQLITE_BTREE_H 17 #define SQLITE_BTREE_H 18 19 /* TODO: This definition is just included so other modules compile. It 20 ** needs to be revisited. 21 */ 22 #define SQLITE_N_BTREE_META 16 23 24 /* 25 ** If defined as non-zero, auto-vacuum is enabled by default. Otherwise 26 ** it must be turned on for each database using "PRAGMA auto_vacuum = 1". 27 */ 28 #ifndef SQLITE_DEFAULT_AUTOVACUUM 29 #define SQLITE_DEFAULT_AUTOVACUUM 0 30 #endif 31 32 #define BTREE_AUTOVACUUM_NONE 0 /* Do not do auto-vacuum */ 33 #define BTREE_AUTOVACUUM_FULL 1 /* Do full auto-vacuum */ 34 #define BTREE_AUTOVACUUM_INCR 2 /* Incremental vacuum */ 35 36 /* 37 ** Forward declarations of structure 38 */ 39 typedef struct Btree Btree; 40 typedef struct BtCursor BtCursor; 41 typedef struct BtShared BtShared; 42 typedef struct BtreePayload BtreePayload; 43 44 45 int sqlite3BtreeOpen( 46 sqlite3_vfs *pVfs, /* VFS to use with this b-tree */ 47 const char *zFilename, /* Name of database file to open */ 48 sqlite3 *db, /* Associated database connection */ 49 Btree **ppBtree, /* Return open Btree* here */ 50 int flags, /* Flags */ 51 int vfsFlags /* Flags passed through to VFS open */ 52 ); 53 54 /* The flags parameter to sqlite3BtreeOpen can be the bitwise or of the 55 ** following values. 56 ** 57 ** NOTE: These values must match the corresponding PAGER_ values in 58 ** pager.h. 59 */ 60 #define BTREE_OMIT_JOURNAL 1 /* Do not create or use a rollback journal */ 61 #define BTREE_MEMORY 2 /* This is an in-memory DB */ 62 #define BTREE_SINGLE 4 /* The file contains at most 1 b-tree */ 63 #define BTREE_UNORDERED 8 /* Use of a hash implementation is OK */ 64 65 int sqlite3BtreeClose(Btree*); 66 int sqlite3BtreeSetCacheSize(Btree*,int); 67 int sqlite3BtreeSetSpillSize(Btree*,int); 68 #if SQLITE_MAX_MMAP_SIZE>0 69 int sqlite3BtreeSetMmapLimit(Btree*,sqlite3_int64); 70 #endif 71 int sqlite3BtreeSetPagerFlags(Btree*,unsigned); 72 int sqlite3BtreeSetPageSize(Btree *p, int nPagesize, int nReserve, int eFix); 73 int sqlite3BtreeGetPageSize(Btree*); 74 int sqlite3BtreeMaxPageCount(Btree*,int); 75 u32 sqlite3BtreeLastPage(Btree*); 76 int sqlite3BtreeSecureDelete(Btree*,int); 77 int sqlite3BtreeGetOptimalReserve(Btree*); 78 int sqlite3BtreeGetReserveNoMutex(Btree *p); 79 int sqlite3BtreeSetAutoVacuum(Btree *, int); 80 int sqlite3BtreeGetAutoVacuum(Btree *); 81 int sqlite3BtreeBeginTrans(Btree*,int,int*); 82 int sqlite3BtreeCommitPhaseOne(Btree*, const char *zMaster); 83 int sqlite3BtreeCommitPhaseTwo(Btree*, int); 84 int sqlite3BtreeCommit(Btree*); 85 int sqlite3BtreeRollback(Btree*,int,int); 86 int sqlite3BtreeBeginStmt(Btree*,int); 87 int sqlite3BtreeCreateTable(Btree*, int*, int flags); 88 int sqlite3BtreeIsInTrans(Btree*); 89 int sqlite3BtreeIsInReadTrans(Btree*); 90 int sqlite3BtreeIsInBackup(Btree*); 91 void *sqlite3BtreeSchema(Btree *, int, void(*)(void *)); 92 int sqlite3BtreeSchemaLocked(Btree *pBtree); 93 #ifndef SQLITE_OMIT_SHARED_CACHE 94 int sqlite3BtreeLockTable(Btree *pBtree, int iTab, u8 isWriteLock); 95 #endif 96 int sqlite3BtreeSavepoint(Btree *, int, int); 97 98 const char *sqlite3BtreeGetFilename(Btree *); 99 const char *sqlite3BtreeGetJournalname(Btree *); 100 int sqlite3BtreeCopyFile(Btree *, Btree *); 101 102 int sqlite3BtreeIncrVacuum(Btree *); 103 104 /* The flags parameter to sqlite3BtreeCreateTable can be the bitwise OR 105 ** of the flags shown below. 106 ** 107 ** Every SQLite table must have either BTREE_INTKEY or BTREE_BLOBKEY set. 108 ** With BTREE_INTKEY, the table key is a 64-bit integer and arbitrary data 109 ** is stored in the leaves. (BTREE_INTKEY is used for SQL tables.) With 110 ** BTREE_BLOBKEY, the key is an arbitrary BLOB and no content is stored 111 ** anywhere - the key is the content. (BTREE_BLOBKEY is used for SQL 112 ** indices.) 113 */ 114 #define BTREE_INTKEY 1 /* Table has only 64-bit signed integer keys */ 115 #define BTREE_BLOBKEY 2 /* Table has keys only - no data */ 116 117 int sqlite3BtreeDropTable(Btree*, int, int*); 118 int sqlite3BtreeClearTable(Btree*, int, int*); 119 int sqlite3BtreeClearTableOfCursor(BtCursor*); 120 int sqlite3BtreeTripAllCursors(Btree*, int, int); 121 122 void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue); 123 int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value); 124 125 int sqlite3BtreeNewDb(Btree *p); 126 127 /* 128 ** The second parameter to sqlite3BtreeGetMeta or sqlite3BtreeUpdateMeta 129 ** should be one of the following values. The integer values are assigned 130 ** to constants so that the offset of the corresponding field in an 131 ** SQLite database header may be found using the following formula: 132 ** 133 ** offset = 36 + (idx * 4) 134 ** 135 ** For example, the free-page-count field is located at byte offset 36 of 136 ** the database file header. The incr-vacuum-flag field is located at 137 ** byte offset 64 (== 36+4*7). 138 ** 139 ** The BTREE_DATA_VERSION value is not really a value stored in the header. 140 ** It is a read-only number computed by the pager. But we merge it with 141 ** the header value access routines since its access pattern is the same. 142 ** Call it a "virtual meta value". 143 */ 144 #define BTREE_FREE_PAGE_COUNT 0 145 #define BTREE_SCHEMA_VERSION 1 146 #define BTREE_FILE_FORMAT 2 147 #define BTREE_DEFAULT_CACHE_SIZE 3 148 #define BTREE_LARGEST_ROOT_PAGE 4 149 #define BTREE_TEXT_ENCODING 5 150 #define BTREE_USER_VERSION 6 151 #define BTREE_INCR_VACUUM 7 152 #define BTREE_APPLICATION_ID 8 153 #define BTREE_DATA_VERSION 15 /* A virtual meta-value */ 154 155 /* 156 ** Kinds of hints that can be passed into the sqlite3BtreeCursorHint() 157 ** interface. 158 ** 159 ** BTREE_HINT_RANGE (arguments: Expr*, Mem*) 160 ** 161 ** The first argument is an Expr* (which is guaranteed to be constant for 162 ** the lifetime of the cursor) that defines constraints on which rows 163 ** might be fetched with this cursor. The Expr* tree may contain 164 ** TK_REGISTER nodes that refer to values stored in the array of registers 165 ** passed as the second parameter. In other words, if Expr.op==TK_REGISTER 166 ** then the value of the node is the value in Mem[pExpr.iTable]. Any 167 ** TK_COLUMN node in the expression tree refers to the Expr.iColumn-th 168 ** column of the b-tree of the cursor. The Expr tree will not contain 169 ** any function calls nor subqueries nor references to b-trees other than 170 ** the cursor being hinted. 171 ** 172 ** The design of the _RANGE hint is aid b-tree implementations that try 173 ** to prefetch content from remote machines - to provide those 174 ** implementations with limits on what needs to be prefetched and thereby 175 ** reduce network bandwidth. 176 ** 177 ** Note that BTREE_HINT_FLAGS with BTREE_BULKLOAD is the only hint used by 178 ** standard SQLite. The other hints are provided for extentions that use 179 ** the SQLite parser and code generator but substitute their own storage 180 ** engine. 181 */ 182 #define BTREE_HINT_RANGE 0 /* Range constraints on queries */ 183 184 /* 185 ** Values that may be OR'd together to form the argument to the 186 ** BTREE_HINT_FLAGS hint for sqlite3BtreeCursorHint(): 187 ** 188 ** The BTREE_BULKLOAD flag is set on index cursors when the index is going 189 ** to be filled with content that is already in sorted order. 190 ** 191 ** The BTREE_SEEK_EQ flag is set on cursors that will get OP_SeekGE or 192 ** OP_SeekLE opcodes for a range search, but where the range of entries 193 ** selected will all have the same key. In other words, the cursor will 194 ** be used only for equality key searches. 195 ** 196 */ 197 #define BTREE_BULKLOAD 0x00000001 /* Used to full index in sorted order */ 198 #define BTREE_SEEK_EQ 0x00000002 /* EQ seeks only - no range seeks */ 199 200 /* 201 ** Flags passed as the third argument to sqlite3BtreeCursor(). 202 ** 203 ** For read-only cursors the wrFlag argument is always zero. For read-write 204 ** cursors it may be set to either (BTREE_WRCSR|BTREE_FORDELETE) or just 205 ** (BTREE_WRCSR). If the BTREE_FORDELETE bit is set, then the cursor will 206 ** only be used by SQLite for the following: 207 ** 208 ** * to seek to and then delete specific entries, and/or 209 ** 210 ** * to read values that will be used to create keys that other 211 ** BTREE_FORDELETE cursors will seek to and delete. 212 ** 213 ** The BTREE_FORDELETE flag is an optimization hint. It is not used by 214 ** by this, the native b-tree engine of SQLite, but it is available to 215 ** alternative storage engines that might be substituted in place of this 216 ** b-tree system. For alternative storage engines in which a delete of 217 ** the main table row automatically deletes corresponding index rows, 218 ** the FORDELETE flag hint allows those alternative storage engines to 219 ** skip a lot of work. Namely: FORDELETE cursors may treat all SEEK 220 ** and DELETE operations as no-ops, and any READ operation against a 221 ** FORDELETE cursor may return a null row: 0x01 0x00. 222 */ 223 #define BTREE_WRCSR 0x00000004 /* read-write cursor */ 224 #define BTREE_FORDELETE 0x00000008 /* Cursor is for seek/delete only */ 225 226 int sqlite3BtreeCursor( 227 Btree*, /* BTree containing table to open */ 228 int iTable, /* Index of root page */ 229 int wrFlag, /* 1 for writing. 0 for read-only */ 230 struct KeyInfo*, /* First argument to compare function */ 231 BtCursor *pCursor /* Space to write cursor structure */ 232 ); 233 BtCursor *sqlite3BtreeFakeValidCursor(void); 234 int sqlite3BtreeCursorSize(void); 235 void sqlite3BtreeCursorZero(BtCursor*); 236 void sqlite3BtreeCursorHintFlags(BtCursor*, unsigned); 237 #ifdef SQLITE_ENABLE_CURSOR_HINTS 238 void sqlite3BtreeCursorHint(BtCursor*, int, ...); 239 #endif 240 241 int sqlite3BtreeCloseCursor(BtCursor*); 242 int sqlite3BtreeMovetoUnpacked( 243 BtCursor*, 244 UnpackedRecord *pUnKey, 245 i64 intKey, 246 int bias, 247 int *pRes 248 ); 249 int sqlite3BtreeCursorHasMoved(BtCursor*); 250 int sqlite3BtreeCursorRestore(BtCursor*, int*); 251 int sqlite3BtreeDelete(BtCursor*, u8 flags); 252 253 /* Allowed flags for sqlite3BtreeDelete() and sqlite3BtreeInsert() */ 254 #define BTREE_SAVEPOSITION 0x02 /* Leave cursor pointing at NEXT or PREV */ 255 #define BTREE_AUXDELETE 0x04 /* not the primary delete operation */ 256 #define BTREE_APPEND 0x08 /* Insert is likely an append */ 257 258 /* An instance of the BtreePayload object describes the content of a single 259 ** entry in either an index or table btree. 260 ** 261 ** Index btrees (used for indexes and also WITHOUT ROWID tables) contain 262 ** an arbitrary key and no data. These btrees have pKey,nKey set to the 263 ** key and the pData,nData,nZero fields are uninitialized. The aMem,nMem 264 ** fields give an array of Mem objects that are a decomposition of the key. 265 ** The nMem field might be zero, indicating that no decomposition is available. 266 ** 267 ** Table btrees (used for rowid tables) contain an integer rowid used as 268 ** the key and passed in the nKey field. The pKey field is zero. 269 ** pData,nData hold the content of the new entry. nZero extra zero bytes 270 ** are appended to the end of the content when constructing the entry. 271 ** The aMem,nMem fields are uninitialized for table btrees. 272 ** 273 ** Field usage summary: 274 ** 275 ** Table BTrees Index Btrees 276 ** 277 ** pKey always NULL encoded key 278 ** nKey the ROWID length of pKey 279 ** pData data not used 280 ** aMem not used decomposed key value 281 ** nMem not used entries in aMem 282 ** nData length of pData not used 283 ** nZero extra zeros after pData not used 284 ** 285 ** This object is used to pass information into sqlite3BtreeInsert(). The 286 ** same information used to be passed as five separate parameters. But placing 287 ** the information into this object helps to keep the interface more 288 ** organized and understandable, and it also helps the resulting code to 289 ** run a little faster by using fewer registers for parameter passing. 290 */ 291 struct BtreePayload { 292 const void *pKey; /* Key content for indexes. NULL for tables */ 293 sqlite3_int64 nKey; /* Size of pKey for indexes. PRIMARY KEY for tabs */ 294 const void *pData; /* Data for tables. */ 295 sqlite3_value *aMem; /* First of nMem value in the unpacked pKey */ 296 u16 nMem; /* Number of aMem[] value. Might be zero */ 297 int nData; /* Size of pData. 0 if none. */ 298 int nZero; /* Extra zero data appended after pData,nData */ 299 }; 300 301 int sqlite3BtreeInsert(BtCursor*, const BtreePayload *pPayload, 302 int flags, int seekResult); 303 int sqlite3BtreeFirst(BtCursor*, int *pRes); 304 int sqlite3BtreeLast(BtCursor*, int *pRes); 305 int sqlite3BtreeNext(BtCursor*, int flags); 306 int sqlite3BtreeEof(BtCursor*); 307 int sqlite3BtreePrevious(BtCursor*, int flags); 308 i64 sqlite3BtreeIntegerKey(BtCursor*); 309 #ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC 310 i64 sqlite3BtreeOffset(BtCursor*); 311 #endif 312 int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*); 313 const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt); 314 u32 sqlite3BtreePayloadSize(BtCursor*); 315 sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor*); 316 317 char *sqlite3BtreeIntegrityCheck(sqlite3*,Btree*,int*aRoot,int nRoot,int,int*); 318 struct Pager *sqlite3BtreePager(Btree*); 319 i64 sqlite3BtreeRowCountEst(BtCursor*); 320 321 #ifndef SQLITE_OMIT_INCRBLOB 322 int sqlite3BtreePayloadChecked(BtCursor*, u32 offset, u32 amt, void*); 323 int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*); 324 void sqlite3BtreeIncrblobCursor(BtCursor *); 325 #endif 326 void sqlite3BtreeClearCursor(BtCursor *); 327 int sqlite3BtreeSetVersion(Btree *pBt, int iVersion); 328 int sqlite3BtreeCursorHasHint(BtCursor*, unsigned int mask); 329 int sqlite3BtreeIsReadonly(Btree *pBt); 330 int sqlite3HeaderSizeBtree(void); 331 332 #ifndef NDEBUG 333 int sqlite3BtreeCursorIsValid(BtCursor*); 334 #endif 335 int sqlite3BtreeCursorIsValidNN(BtCursor*); 336 337 #ifndef SQLITE_OMIT_BTREECOUNT 338 int sqlite3BtreeCount(sqlite3*, BtCursor*, i64*); 339 #endif 340 341 #ifdef SQLITE_TEST 342 int sqlite3BtreeCursorInfo(BtCursor*, int*, int); 343 void sqlite3BtreeCursorList(Btree*); 344 #endif 345 346 #ifndef SQLITE_OMIT_WAL 347 int sqlite3BtreeCheckpoint(Btree*, int, int *, int *); 348 #endif 349 350 /* 351 ** If we are not using shared cache, then there is no need to 352 ** use mutexes to access the BtShared structures. So make the 353 ** Enter and Leave procedures no-ops. 354 */ 355 #ifndef SQLITE_OMIT_SHARED_CACHE 356 void sqlite3BtreeEnter(Btree*); 357 void sqlite3BtreeEnterAll(sqlite3*); 358 int sqlite3BtreeSharable(Btree*); 359 void sqlite3BtreeEnterCursor(BtCursor*); 360 int sqlite3BtreeConnectionCount(Btree*); 361 #else 362 # define sqlite3BtreeEnter(X) 363 # define sqlite3BtreeEnterAll(X) 364 # define sqlite3BtreeSharable(X) 0 365 # define sqlite3BtreeEnterCursor(X) 366 # define sqlite3BtreeConnectionCount(X) 1 367 #endif 368 369 #if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE 370 void sqlite3BtreeLeave(Btree*); 371 void sqlite3BtreeLeaveCursor(BtCursor*); 372 void sqlite3BtreeLeaveAll(sqlite3*); 373 #ifndef NDEBUG 374 /* These routines are used inside assert() statements only. */ 375 int sqlite3BtreeHoldsMutex(Btree*); 376 int sqlite3BtreeHoldsAllMutexes(sqlite3*); 377 int sqlite3SchemaMutexHeld(sqlite3*,int,Schema*); 378 #endif 379 #else 380 381 # define sqlite3BtreeLeave(X) 382 # define sqlite3BtreeLeaveCursor(X) 383 # define sqlite3BtreeLeaveAll(X) 384 385 # define sqlite3BtreeHoldsMutex(X) 1 386 # define sqlite3BtreeHoldsAllMutexes(X) 1 387 # define sqlite3SchemaMutexHeld(X,Y,Z) 1 388 #endif 389 390 391 #endif /* SQLITE_BTREE_H */ 392