1 /* 2 ** 2003 September 6 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 is the header file for information that is private to the 13 ** VDBE. This information used to all be at the top of the single 14 ** source code file "vdbe.c". When that file became too big (over 15 ** 6000 lines long) it was split up into several smaller files and 16 ** this header information was factored out. 17 ** 18 ** $Id: vdbeInt.h,v 1.149 2008/06/25 00:12:41 drh Exp $ 19 */ 20 #ifndef _VDBEINT_H_ 21 #define _VDBEINT_H_ 22 23 /* 24 ** intToKey() and keyToInt() used to transform the rowid. But with 25 ** the latest versions of the design they are no-ops. 26 */ 27 #define keyToInt(X) (X) 28 #define intToKey(X) (X) 29 30 31 /* 32 ** SQL is translated into a sequence of instructions to be 33 ** executed by a virtual machine. Each instruction is an instance 34 ** of the following structure. 35 */ 36 typedef struct VdbeOp Op; 37 38 /* 39 ** Boolean values 40 */ 41 typedef unsigned char Bool; 42 43 /* 44 ** A cursor is a pointer into a single BTree within a database file. 45 ** The cursor can seek to a BTree entry with a particular key, or 46 ** loop over all entries of the Btree. You can also insert new BTree 47 ** entries or retrieve the key or data from the entry that the cursor 48 ** is currently pointing to. 49 ** 50 ** Every cursor that the virtual machine has open is represented by an 51 ** instance of the following structure. 52 ** 53 ** If the Cursor.isTriggerRow flag is set it means that this cursor is 54 ** really a single row that represents the NEW or OLD pseudo-table of 55 ** a row trigger. The data for the row is stored in Cursor.pData and 56 ** the rowid is in Cursor.iKey. 57 */ 58 struct Cursor { 59 BtCursor *pCursor; /* The cursor structure of the backend */ 60 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ 61 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ 62 i64 nextRowid; /* Next rowid returned by OP_NewRowid */ 63 Bool zeroed; /* True if zeroed out and ready for reuse */ 64 Bool rowidIsValid; /* True if lastRowid is valid */ 65 Bool atFirst; /* True if pointing to first entry */ 66 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 67 Bool nullRow; /* True if pointing to a row with no data */ 68 Bool nextRowidValid; /* True if the nextRowid field is valid */ 69 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ 70 Bool ephemPseudoTable; 71 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 72 Bool isTable; /* True if a table requiring integer keys */ 73 Bool isIndex; /* True if an index containing keys only - no data */ 74 u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */ 75 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 76 Btree *pBt; /* Separate file holding temporary table */ 77 int nData; /* Number of bytes in pData */ 78 char *pData; /* Data for a NEW or OLD pseudo-table */ 79 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ 80 u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */ 81 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 82 int nField; /* Number of fields in the header */ 83 i64 seqCount; /* Sequence counter */ 84 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 85 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 86 87 /* Cached information about the header for the data record that the 88 ** cursor is currently pointing to. Only valid if cacheValid is true. 89 ** aRow might point to (ephemeral) data for the current row, or it might 90 ** be NULL. 91 */ 92 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 93 int payloadSize; /* Total number of bytes in the record */ 94 u32 *aType; /* Type values for all entries in the record */ 95 u32 *aOffset; /* Cached offsets to the start of each columns data */ 96 u8 *aRow; /* Data for the current row, if all on one page */ 97 }; 98 typedef struct Cursor Cursor; 99 100 /* 101 ** A value for Cursor.cacheValid that means the cache is always invalid. 102 */ 103 #define CACHE_STALE 0 104 105 /* 106 ** Internally, the vdbe manipulates nearly all SQL values as Mem 107 ** structures. Each Mem struct may cache multiple representations (string, 108 ** integer etc.) of the same value. A value (and therefore Mem structure) 109 ** has the following properties: 110 ** 111 ** Each value has a manifest type. The manifest type of the value stored 112 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 113 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 114 ** SQLITE_BLOB. 115 */ 116 struct Mem { 117 union { 118 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */ 119 FuncDef *pDef; /* Used only when flags==MEM_Agg */ 120 } u; 121 double r; /* Real value */ 122 sqlite3 *db; /* The associated database connection */ 123 char *z; /* String or BLOB value */ 124 int n; /* Number of characters in string value, excluding '\0' */ 125 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 126 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ 127 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ 128 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 129 char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */ 130 }; 131 132 /* One or more of the following flags are set to indicate the validOK 133 ** representations of the value stored in the Mem struct. 134 ** 135 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 136 ** No other flags may be set in this case. 137 ** 138 ** If the MEM_Str flag is set then Mem.z points at a string representation. 139 ** Usually this is encoded in the same unicode encoding as the main 140 ** database (see below for exceptions). If the MEM_Term flag is also 141 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 142 ** flags may coexist with the MEM_Str flag. 143 ** 144 ** Multiple of these values can appear in Mem.flags. But only one 145 ** at a time can appear in Mem.type. 146 */ 147 #define MEM_Null 0x0001 /* Value is NULL */ 148 #define MEM_Str 0x0002 /* Value is a string */ 149 #define MEM_Int 0x0004 /* Value is an integer */ 150 #define MEM_Real 0x0008 /* Value is a real number */ 151 #define MEM_Blob 0x0010 /* Value is a BLOB */ 152 153 #define MemSetTypeFlag(p, f) \ 154 ((p)->flags = ((p)->flags&~(MEM_Int|MEM_Real|MEM_Null|MEM_Blob|MEM_Str))|f) 155 156 /* Whenever Mem contains a valid string or blob representation, one of 157 ** the following flags must be set to determine the memory management 158 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 159 ** string is \000 or \u0000 terminated 160 */ 161 #define MEM_Term 0x0020 /* String rep is nul terminated */ 162 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ 163 #define MEM_Static 0x0080 /* Mem.z points to a static string */ 164 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ 165 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */ 166 #define MEM_Zero 0x0800 /* Mem.i contains count of 0s appended to blob */ 167 168 #ifdef SQLITE_OMIT_INCRBLOB 169 #undef MEM_Zero 170 #define MEM_Zero 0x0000 171 #endif 172 173 174 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 175 ** additional information about auxiliary information bound to arguments 176 ** of the function. This is used to implement the sqlite3_get_auxdata() 177 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 178 ** that can be associated with a constant argument to a function. This 179 ** allows functions such as "regexp" to compile their constant regular 180 ** expression argument once and reused the compiled code for multiple 181 ** invocations. 182 */ 183 struct VdbeFunc { 184 FuncDef *pFunc; /* The definition of the function */ 185 int nAux; /* Number of entries allocated for apAux[] */ 186 struct AuxData { 187 void *pAux; /* Aux data for the i-th argument */ 188 void (*xDelete)(void *); /* Destructor for the aux data */ 189 } apAux[1]; /* One slot for each function argument */ 190 }; 191 192 /* 193 ** The "context" argument for a installable function. A pointer to an 194 ** instance of this structure is the first argument to the routines used 195 ** implement the SQL functions. 196 ** 197 ** There is a typedef for this structure in sqlite.h. So all routines, 198 ** even the public interface to SQLite, can use a pointer to this structure. 199 ** But this file is the only place where the internal details of this 200 ** structure are known. 201 ** 202 ** This structure is defined inside of vdbeInt.h because it uses substructures 203 ** (Mem) which are only defined there. 204 */ 205 struct sqlite3_context { 206 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 207 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 208 Mem s; /* The return value is stored here */ 209 Mem *pMem; /* Memory cell used to store aggregate context */ 210 int isError; /* Error code returned by the function. */ 211 CollSeq *pColl; /* Collating sequence */ 212 }; 213 214 /* 215 ** A Set structure is used for quick testing to see if a value 216 ** is part of a small set. Sets are used to implement code like 217 ** this: 218 ** x.y IN ('hi','hoo','hum') 219 */ 220 typedef struct Set Set; 221 struct Set { 222 Hash hash; /* A set is just a hash table */ 223 HashElem *prev; /* Previously accessed hash elemen */ 224 }; 225 226 /* 227 ** A FifoPage structure holds a single page of valves. Pages are arranged 228 ** in a list. 229 */ 230 typedef struct FifoPage FifoPage; 231 struct FifoPage { 232 int nSlot; /* Number of entries aSlot[] */ 233 int iWrite; /* Push the next value into this entry in aSlot[] */ 234 int iRead; /* Read the next value from this entry in aSlot[] */ 235 FifoPage *pNext; /* Next page in the fifo */ 236 i64 aSlot[1]; /* One or more slots for rowid values */ 237 }; 238 239 /* 240 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation 241 ** of that structure is private to this file. 242 ** 243 ** The Fifo structure describes the entire fifo. 244 */ 245 typedef struct Fifo Fifo; 246 struct Fifo { 247 int nEntry; /* Total number of entries */ 248 FifoPage *pFirst; /* First page on the list */ 249 FifoPage *pLast; /* Last page on the list */ 250 }; 251 252 /* 253 ** A Context stores the last insert rowid, the last statement change count, 254 ** and the current statement change count (i.e. changes since last statement). 255 ** The current keylist is also stored in the context. 256 ** Elements of Context structure type make up the ContextStack, which is 257 ** updated by the ContextPush and ContextPop opcodes (used by triggers). 258 ** The context is pushed before executing a trigger a popped when the 259 ** trigger finishes. 260 */ 261 typedef struct Context Context; 262 struct Context { 263 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 264 int nChange; /* Statement changes (Vdbe.nChanges) */ 265 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */ 266 }; 267 268 /* 269 ** An instance of the virtual machine. This structure contains the complete 270 ** state of the virtual machine. 271 ** 272 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 273 ** is really a pointer to an instance of this structure. 274 ** 275 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 276 ** any virtual table method invocations made by the vdbe program. It is 277 ** set to 2 for xDestroy method calls and 1 for all other methods. This 278 ** variable is used for two purposes: to allow xDestroy methods to execute 279 ** "DROP TABLE" statements and to prevent some nasty side effects of 280 ** malloc failure when SQLite is invoked recursively by a virtual table 281 ** method function. 282 */ 283 struct Vdbe { 284 sqlite3 *db; /* The whole database */ 285 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 286 int nOp; /* Number of instructions in the program */ 287 int nOpAlloc; /* Number of slots allocated for aOp[] */ 288 Op *aOp; /* Space to hold the virtual machine's program */ 289 int nLabel; /* Number of labels used */ 290 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 291 int *aLabel; /* Space to hold the labels */ 292 Mem **apArg; /* Arguments to currently executing user function */ 293 Mem *aColName; /* Column names to return */ 294 int nCursor; /* Number of slots in apCsr[] */ 295 Cursor **apCsr; /* One element of this array for each open cursor */ 296 int nVar; /* Number of entries in aVar[] */ 297 Mem *aVar; /* Values for the OP_Variable opcode. */ 298 char **azVar; /* Name of variables */ 299 int okVar; /* True if azVar[] has been initialized */ 300 int magic; /* Magic number for sanity checking */ 301 int nMem; /* Number of memory locations currently allocated */ 302 Mem *aMem; /* The memory locations */ 303 int nCallback; /* Number of callbacks invoked so far */ 304 int cacheCtr; /* Cursor row cache generation counter */ 305 Fifo sFifo; /* A list of ROWIDs */ 306 int contextStackTop; /* Index of top element in the context stack */ 307 int contextStackDepth; /* The size of the "context" stack */ 308 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 309 int pc; /* The program counter */ 310 int rc; /* Value to return */ 311 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */ 312 int errorAction; /* Recovery action to do in case of an error */ 313 int inTempTrans; /* True if temp database is transactioned */ 314 int nResColumn; /* Number of columns in one row of the result set */ 315 char **azResColumn; /* Values for one row of result */ 316 char *zErrMsg; /* Error message written here */ 317 Mem *pResultSet; /* Pointer to an array of results */ 318 u8 explain; /* True if EXPLAIN present on SQL command */ 319 u8 changeCntOn; /* True to update the change-counter */ 320 u8 aborted; /* True if ROLLBACK in another VM causes an abort */ 321 u8 expired; /* True if the VM needs to be recompiled */ 322 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 323 u8 inVtabMethod; /* See comments above */ 324 int nChange; /* Number of db changes made since last reset */ 325 i64 startTime; /* Time when query started - used for profiling */ 326 int btreeMask; /* Bitmask of db->aDb[] entries referenced */ 327 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */ 328 int nSql; /* Number of bytes in zSql */ 329 char *zSql; /* Text of the SQL statement that generated this */ 330 #ifdef SQLITE_DEBUG 331 FILE *trace; /* Write an execution trace here, if not NULL */ 332 #endif 333 int openedStatement; /* True if this VM has opened a statement journal */ 334 #ifdef SQLITE_SSE 335 int fetchId; /* Statement number used by sqlite3_fetch_statement */ 336 int lru; /* Counter used for LRU cache replacement */ 337 #endif 338 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 339 Vdbe *pLruPrev; 340 Vdbe *pLruNext; 341 #endif 342 }; 343 344 /* 345 ** An instance of the following structure holds information about a 346 ** single index record that has already been parsed out into individual 347 ** values. 348 ** 349 ** A record is an object that contains one or more fields of data. 350 ** Records are used to store the content of a table row and to store 351 ** the key of an index. A blob encoding of a record is created by 352 ** the OP_MakeRecord opcode of the VDBE and is disassemblied by the 353 ** OP_Column opcode. 354 ** 355 ** This structure holds a record that has already been disassembled 356 ** into its constitutent fields. 357 */ 358 struct UnpackedRecord { 359 KeyInfo *pKeyInfo; /* Collation and sort-order information */ 360 u16 nField; /* Number of entries in apMem[] */ 361 u8 needFree; /* True if memory obtained from sqlite3_malloc() */ 362 u8 needDestroy; /* True if apMem[]s should be destroyed on close */ 363 Mem *aMem; /* Values */ 364 }; 365 366 /* 367 ** The following are allowed values for Vdbe.magic 368 */ 369 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 370 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 371 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 372 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 373 374 /* 375 ** Function prototypes 376 */ 377 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*); 378 void sqliteVdbePopStack(Vdbe*,int); 379 int sqlite3VdbeCursorMoveto(Cursor*); 380 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 381 void sqlite3VdbePrintOp(FILE*, int, Op*); 382 #endif 383 int sqlite3VdbeSerialTypeLen(u32); 384 u32 sqlite3VdbeSerialType(Mem*, int); 385 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 386 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 387 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 388 389 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 390 int sqlite3VdbeIdxKeyCompare(Cursor*,UnpackedRecord *,int,const unsigned char*,int*); 391 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 392 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 393 int sqlite3VdbeIdxRowidLen(const u8*); 394 int sqlite3VdbeExec(Vdbe*); 395 int sqlite3VdbeList(Vdbe*); 396 int sqlite3VdbeHalt(Vdbe*); 397 int sqlite3VdbeChangeEncoding(Mem *, int); 398 int sqlite3VdbeMemTooBig(Mem*); 399 int sqlite3VdbeMemCopy(Mem*, const Mem*); 400 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 401 void sqlite3VdbeMemMove(Mem*, Mem*); 402 int sqlite3VdbeMemNulTerminate(Mem*); 403 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 404 void sqlite3VdbeMemSetInt64(Mem*, i64); 405 void sqlite3VdbeMemSetDouble(Mem*, double); 406 void sqlite3VdbeMemSetNull(Mem*); 407 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 408 int sqlite3VdbeMemMakeWriteable(Mem*); 409 int sqlite3VdbeMemDynamicify(Mem*); 410 int sqlite3VdbeMemStringify(Mem*, int); 411 i64 sqlite3VdbeIntValue(Mem*); 412 int sqlite3VdbeMemIntegerify(Mem*); 413 double sqlite3VdbeRealValue(Mem*); 414 void sqlite3VdbeIntegerAffinity(Mem*); 415 int sqlite3VdbeMemRealify(Mem*); 416 int sqlite3VdbeMemNumerify(Mem*); 417 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 418 void sqlite3VdbeMemRelease(Mem *p); 419 void sqlite3VdbeMemReleaseExternal(Mem *p); 420 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 421 const char *sqlite3OpcodeName(int); 422 int sqlite3VdbeOpcodeHasProperty(int, int); 423 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve); 424 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 425 int sqlite3VdbeReleaseBuffers(Vdbe *p); 426 #endif 427 428 #ifndef NDEBUG 429 void sqlite3VdbeMemSanity(Mem*); 430 #endif 431 int sqlite3VdbeMemTranslate(Mem*, u8); 432 #ifdef SQLITE_DEBUG 433 void sqlite3VdbePrintSql(Vdbe*); 434 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 435 #endif 436 int sqlite3VdbeMemHandleBom(Mem *pMem); 437 void sqlite3VdbeFifoInit(Fifo*); 438 int sqlite3VdbeFifoPush(Fifo*, i64); 439 int sqlite3VdbeFifoPop(Fifo*, i64*); 440 void sqlite3VdbeFifoClear(Fifo*); 441 442 #ifndef SQLITE_OMIT_INCRBLOB 443 int sqlite3VdbeMemExpandBlob(Mem *); 444 #else 445 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK 446 #endif 447 448 #endif /* !defined(_VDBEINT_H_) */ 449