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 Pgno sqlite3BtreeMaxPageCount(Btree*,Pgno); 75 Pgno sqlite3BtreeLastPage(Btree*); 76 int sqlite3BtreeSecureDelete(Btree*,int); 77 int sqlite3BtreeGetRequestedReserve(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*); 83 int sqlite3BtreeCommitPhaseTwo(Btree*, int); 84 int sqlite3BtreeCommit(Btree*); 85 int sqlite3BtreeRollback(Btree*,int,int); 86 int sqlite3BtreeBeginStmt(Btree*,int); 87 int sqlite3BtreeCreateTable(Btree*, Pgno*, int flags); 88 int sqlite3BtreeTxnState(Btree*); 89 int sqlite3BtreeIsInBackup(Btree*); 90 void *sqlite3BtreeSchema(Btree *, int, void(*)(void *)); 91 int sqlite3BtreeSchemaLocked(Btree *pBtree); 92 #ifndef SQLITE_OMIT_SHARED_CACHE 93 int sqlite3BtreeLockTable(Btree *pBtree, int iTab, u8 isWriteLock); 94 #endif 95 int sqlite3BtreeSavepoint(Btree *, int, int); 96 97 const char *sqlite3BtreeGetFilename(Btree *); 98 const char *sqlite3BtreeGetJournalname(Btree *); 99 int sqlite3BtreeCopyFile(Btree *, Btree *); 100 101 int sqlite3BtreeIncrVacuum(Btree *); 102 103 /* The flags parameter to sqlite3BtreeCreateTable can be the bitwise OR 104 ** of the flags shown below. 105 ** 106 ** Every SQLite table must have either BTREE_INTKEY or BTREE_BLOBKEY set. 107 ** With BTREE_INTKEY, the table key is a 64-bit integer and arbitrary data 108 ** is stored in the leaves. (BTREE_INTKEY is used for SQL tables.) With 109 ** BTREE_BLOBKEY, the key is an arbitrary BLOB and no content is stored 110 ** anywhere - the key is the content. (BTREE_BLOBKEY is used for SQL 111 ** indices.) 112 */ 113 #define BTREE_INTKEY 1 /* Table has only 64-bit signed integer keys */ 114 #define BTREE_BLOBKEY 2 /* Table has keys only - no data */ 115 116 int sqlite3BtreeDropTable(Btree*, int, int*); 117 int sqlite3BtreeClearTable(Btree*, int, int*); 118 int sqlite3BtreeClearTableOfCursor(BtCursor*); 119 int sqlite3BtreeTripAllCursors(Btree*, int, int); 120 121 void sqlite3BtreeGetMeta(Btree *pBtree, int idx, u32 *pValue); 122 int sqlite3BtreeUpdateMeta(Btree*, int idx, u32 value); 123 124 int sqlite3BtreeNewDb(Btree *p); 125 126 /* 127 ** The second parameter to sqlite3BtreeGetMeta or sqlite3BtreeUpdateMeta 128 ** should be one of the following values. The integer values are assigned 129 ** to constants so that the offset of the corresponding field in an 130 ** SQLite database header may be found using the following formula: 131 ** 132 ** offset = 36 + (idx * 4) 133 ** 134 ** For example, the free-page-count field is located at byte offset 36 of 135 ** the database file header. The incr-vacuum-flag field is located at 136 ** byte offset 64 (== 36+4*7). 137 ** 138 ** The BTREE_DATA_VERSION value is not really a value stored in the header. 139 ** It is a read-only number computed by the pager. But we merge it with 140 ** the header value access routines since its access pattern is the same. 141 ** Call it a "virtual meta value". 142 */ 143 #define BTREE_FREE_PAGE_COUNT 0 144 #define BTREE_SCHEMA_VERSION 1 145 #define BTREE_FILE_FORMAT 2 146 #define BTREE_DEFAULT_CACHE_SIZE 3 147 #define BTREE_LARGEST_ROOT_PAGE 4 148 #define BTREE_TEXT_ENCODING 5 149 #define BTREE_USER_VERSION 6 150 #define BTREE_INCR_VACUUM 7 151 #define BTREE_APPLICATION_ID 8 152 #define BTREE_DATA_VERSION 15 /* A virtual meta-value */ 153 154 /* 155 ** Kinds of hints that can be passed into the sqlite3BtreeCursorHint() 156 ** interface. 157 ** 158 ** BTREE_HINT_RANGE (arguments: Expr*, Mem*) 159 ** 160 ** The first argument is an Expr* (which is guaranteed to be constant for 161 ** the lifetime of the cursor) that defines constraints on which rows 162 ** might be fetched with this cursor. The Expr* tree may contain 163 ** TK_REGISTER nodes that refer to values stored in the array of registers 164 ** passed as the second parameter. In other words, if Expr.op==TK_REGISTER 165 ** then the value of the node is the value in Mem[pExpr.iTable]. Any 166 ** TK_COLUMN node in the expression tree refers to the Expr.iColumn-th 167 ** column of the b-tree of the cursor. The Expr tree will not contain 168 ** any function calls nor subqueries nor references to b-trees other than 169 ** the cursor being hinted. 170 ** 171 ** The design of the _RANGE hint is aid b-tree implementations that try 172 ** to prefetch content from remote machines - to provide those 173 ** implementations with limits on what needs to be prefetched and thereby 174 ** reduce network bandwidth. 175 ** 176 ** Note that BTREE_HINT_FLAGS with BTREE_BULKLOAD is the only hint used by 177 ** standard SQLite. The other hints are provided for extentions that use 178 ** the SQLite parser and code generator but substitute their own storage 179 ** engine. 180 */ 181 #define BTREE_HINT_RANGE 0 /* Range constraints on queries */ 182 183 /* 184 ** Values that may be OR'd together to form the argument to the 185 ** BTREE_HINT_FLAGS hint for sqlite3BtreeCursorHint(): 186 ** 187 ** The BTREE_BULKLOAD flag is set on index cursors when the index is going 188 ** to be filled with content that is already in sorted order. 189 ** 190 ** The BTREE_SEEK_EQ flag is set on cursors that will get OP_SeekGE or 191 ** OP_SeekLE opcodes for a range search, but where the range of entries 192 ** selected will all have the same key. In other words, the cursor will 193 ** be used only for equality key searches. 194 ** 195 */ 196 #define BTREE_BULKLOAD 0x00000001 /* Used to full index in sorted order */ 197 #define BTREE_SEEK_EQ 0x00000002 /* EQ seeks only - no range seeks */ 198 199 /* 200 ** Flags passed as the third argument to sqlite3BtreeCursor(). 201 ** 202 ** For read-only cursors the wrFlag argument is always zero. For read-write 203 ** cursors it may be set to either (BTREE_WRCSR|BTREE_FORDELETE) or just 204 ** (BTREE_WRCSR). If the BTREE_FORDELETE bit is set, then the cursor will 205 ** only be used by SQLite for the following: 206 ** 207 ** * to seek to and then delete specific entries, and/or 208 ** 209 ** * to read values that will be used to create keys that other 210 ** BTREE_FORDELETE cursors will seek to and delete. 211 ** 212 ** The BTREE_FORDELETE flag is an optimization hint. It is not used by 213 ** by this, the native b-tree engine of SQLite, but it is available to 214 ** alternative storage engines that might be substituted in place of this 215 ** b-tree system. For alternative storage engines in which a delete of 216 ** the main table row automatically deletes corresponding index rows, 217 ** the FORDELETE flag hint allows those alternative storage engines to 218 ** skip a lot of work. Namely: FORDELETE cursors may treat all SEEK 219 ** and DELETE operations as no-ops, and any READ operation against a 220 ** FORDELETE cursor may return a null row: 0x01 0x00. 221 */ 222 #define BTREE_WRCSR 0x00000004 /* read-write cursor */ 223 #define BTREE_FORDELETE 0x00000008 /* Cursor is for seek/delete only */ 224 225 int sqlite3BtreeCursor( 226 Btree*, /* BTree containing table to open */ 227 Pgno iTable, /* Index of root page */ 228 int wrFlag, /* 1 for writing. 0 for read-only */ 229 struct KeyInfo*, /* First argument to compare function */ 230 BtCursor *pCursor /* Space to write cursor structure */ 231 ); 232 BtCursor *sqlite3BtreeFakeValidCursor(void); 233 int sqlite3BtreeCursorSize(void); 234 void sqlite3BtreeCursorZero(BtCursor*); 235 void sqlite3BtreeCursorHintFlags(BtCursor*, unsigned); 236 #ifdef SQLITE_ENABLE_CURSOR_HINTS 237 void sqlite3BtreeCursorHint(BtCursor*, int, ...); 238 #endif 239 240 int sqlite3BtreeCloseCursor(BtCursor*); 241 int sqlite3BtreeMovetoUnpacked( 242 BtCursor*, 243 UnpackedRecord *pUnKey, 244 i64 intKey, 245 int bias, 246 int *pRes 247 ); 248 int sqlite3BtreeCursorHasMoved(BtCursor*); 249 int sqlite3BtreeCursorRestore(BtCursor*, int*); 250 int sqlite3BtreeDelete(BtCursor*, u8 flags); 251 252 /* Allowed flags for sqlite3BtreeDelete() and sqlite3BtreeInsert() */ 253 #define BTREE_SAVEPOSITION 0x02 /* Leave cursor pointing at NEXT or PREV */ 254 #define BTREE_AUXDELETE 0x04 /* not the primary delete operation */ 255 #define BTREE_APPEND 0x08 /* Insert is likely an append */ 256 257 /* An instance of the BtreePayload object describes the content of a single 258 ** entry in either an index or table btree. 259 ** 260 ** Index btrees (used for indexes and also WITHOUT ROWID tables) contain 261 ** an arbitrary key and no data. These btrees have pKey,nKey set to the 262 ** key and the pData,nData,nZero fields are uninitialized. The aMem,nMem 263 ** fields give an array of Mem objects that are a decomposition of the key. 264 ** The nMem field might be zero, indicating that no decomposition is available. 265 ** 266 ** Table btrees (used for rowid tables) contain an integer rowid used as 267 ** the key and passed in the nKey field. The pKey field is zero. 268 ** pData,nData hold the content of the new entry. nZero extra zero bytes 269 ** are appended to the end of the content when constructing the entry. 270 ** The aMem,nMem fields are uninitialized for table btrees. 271 ** 272 ** Field usage summary: 273 ** 274 ** Table BTrees Index Btrees 275 ** 276 ** pKey always NULL encoded key 277 ** nKey the ROWID length of pKey 278 ** pData data not used 279 ** aMem not used decomposed key value 280 ** nMem not used entries in aMem 281 ** nData length of pData not used 282 ** nZero extra zeros after pData not used 283 ** 284 ** This object is used to pass information into sqlite3BtreeInsert(). The 285 ** same information used to be passed as five separate parameters. But placing 286 ** the information into this object helps to keep the interface more 287 ** organized and understandable, and it also helps the resulting code to 288 ** run a little faster by using fewer registers for parameter passing. 289 */ 290 struct BtreePayload { 291 const void *pKey; /* Key content for indexes. NULL for tables */ 292 sqlite3_int64 nKey; /* Size of pKey for indexes. PRIMARY KEY for tabs */ 293 const void *pData; /* Data for tables. */ 294 sqlite3_value *aMem; /* First of nMem value in the unpacked pKey */ 295 u16 nMem; /* Number of aMem[] value. Might be zero */ 296 int nData; /* Size of pData. 0 if none. */ 297 int nZero; /* Extra zero data appended after pData,nData */ 298 }; 299 300 int sqlite3BtreeInsert(BtCursor*, const BtreePayload *pPayload, 301 int flags, int seekResult); 302 int sqlite3BtreeFirst(BtCursor*, int *pRes); 303 int sqlite3BtreeLast(BtCursor*, int *pRes); 304 int sqlite3BtreeNext(BtCursor*, int flags); 305 int sqlite3BtreeEof(BtCursor*); 306 int sqlite3BtreePrevious(BtCursor*, int flags); 307 i64 sqlite3BtreeIntegerKey(BtCursor*); 308 void sqlite3BtreeCursorPin(BtCursor*); 309 void sqlite3BtreeCursorUnpin(BtCursor*); 310 #ifdef SQLITE_ENABLE_OFFSET_SQL_FUNC 311 i64 sqlite3BtreeOffset(BtCursor*); 312 #endif 313 int sqlite3BtreePayload(BtCursor*, u32 offset, u32 amt, void*); 314 const void *sqlite3BtreePayloadFetch(BtCursor*, u32 *pAmt); 315 u32 sqlite3BtreePayloadSize(BtCursor*); 316 sqlite3_int64 sqlite3BtreeMaxRecordSize(BtCursor*); 317 318 char *sqlite3BtreeIntegrityCheck(sqlite3*,Btree*,Pgno*aRoot,int nRoot,int,int*); 319 struct Pager *sqlite3BtreePager(Btree*); 320 i64 sqlite3BtreeRowCountEst(BtCursor*); 321 322 #ifndef SQLITE_OMIT_INCRBLOB 323 int sqlite3BtreePayloadChecked(BtCursor*, u32 offset, u32 amt, void*); 324 int sqlite3BtreePutData(BtCursor*, u32 offset, u32 amt, void*); 325 void sqlite3BtreeIncrblobCursor(BtCursor *); 326 #endif 327 void sqlite3BtreeClearCursor(BtCursor *); 328 int sqlite3BtreeSetVersion(Btree *pBt, int iVersion); 329 int sqlite3BtreeCursorHasHint(BtCursor*, unsigned int mask); 330 int sqlite3BtreeIsReadonly(Btree *pBt); 331 int sqlite3HeaderSizeBtree(void); 332 333 #ifdef SQLITE_DEBUG 334 sqlite3_uint64 sqlite3BtreeSeekCount(Btree*); 335 #else 336 # define sqlite3BtreeSeekCount(X) 0 337 #endif 338 339 #ifndef NDEBUG 340 int sqlite3BtreeCursorIsValid(BtCursor*); 341 #endif 342 int sqlite3BtreeCursorIsValidNN(BtCursor*); 343 344 int sqlite3BtreeCount(sqlite3*, BtCursor*, i64*); 345 346 #ifdef SQLITE_TEST 347 int sqlite3BtreeCursorInfo(BtCursor*, int*, int); 348 void sqlite3BtreeCursorList(Btree*); 349 #endif 350 351 #ifndef SQLITE_OMIT_WAL 352 int sqlite3BtreeCheckpoint(Btree*, int, int *, int *); 353 #endif 354 355 /* 356 ** If we are not using shared cache, then there is no need to 357 ** use mutexes to access the BtShared structures. So make the 358 ** Enter and Leave procedures no-ops. 359 */ 360 #ifndef SQLITE_OMIT_SHARED_CACHE 361 void sqlite3BtreeEnter(Btree*); 362 void sqlite3BtreeEnterAll(sqlite3*); 363 int sqlite3BtreeSharable(Btree*); 364 void sqlite3BtreeEnterCursor(BtCursor*); 365 int sqlite3BtreeConnectionCount(Btree*); 366 #else 367 # define sqlite3BtreeEnter(X) 368 # define sqlite3BtreeEnterAll(X) 369 # define sqlite3BtreeSharable(X) 0 370 # define sqlite3BtreeEnterCursor(X) 371 # define sqlite3BtreeConnectionCount(X) 1 372 #endif 373 374 #if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE 375 void sqlite3BtreeLeave(Btree*); 376 void sqlite3BtreeLeaveCursor(BtCursor*); 377 void sqlite3BtreeLeaveAll(sqlite3*); 378 #ifndef NDEBUG 379 /* These routines are used inside assert() statements only. */ 380 int sqlite3BtreeHoldsMutex(Btree*); 381 int sqlite3BtreeHoldsAllMutexes(sqlite3*); 382 int sqlite3SchemaMutexHeld(sqlite3*,int,Schema*); 383 #endif 384 #else 385 386 # define sqlite3BtreeLeave(X) 387 # define sqlite3BtreeLeaveCursor(X) 388 # define sqlite3BtreeLeaveAll(X) 389 390 # define sqlite3BtreeHoldsMutex(X) 1 391 # define sqlite3BtreeHoldsAllMutexes(X) 1 392 # define sqlite3SchemaMutexHeld(X,Y,Z) 1 393 #endif 394 395 396 #endif /* SQLITE_BTREE_H */ 397