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 1.169 2009/04/22 02:15:48 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 VdbeCursor.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 VdbeCursor.pData and 56 ** the rowid is in VdbeCursor.iKey. 57 */ 58 struct VdbeCursor { 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 Bool zeroed; /* True if zeroed out and ready for reuse */ 63 Bool rowidIsValid; /* True if lastRowid is valid */ 64 Bool atFirst; /* True if pointing to first entry */ 65 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 66 Bool nullRow; /* True if pointing to a row with no data */ 67 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ 68 Bool ephemPseudoTable; 69 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 70 Bool isTable; /* True if a table requiring integer keys */ 71 Bool isIndex; /* True if an index containing keys only - no data */ 72 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 73 Btree *pBt; /* Separate file holding temporary table */ 74 int nData; /* Number of bytes in pData */ 75 char *pData; /* Data for a NEW or OLD pseudo-table */ 76 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ 77 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 78 int nField; /* Number of fields in the header */ 79 i64 seqCount; /* Sequence counter */ 80 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 81 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 82 83 /* Cached information about the header for the data record that the 84 ** cursor is currently pointing to. Only valid if cacheValid is true. 85 ** aRow might point to (ephemeral) data for the current row, or it might 86 ** be NULL. 87 */ 88 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 89 int payloadSize; /* Total number of bytes in the record */ 90 u32 *aType; /* Type values for all entries in the record */ 91 u32 *aOffset; /* Cached offsets to the start of each columns data */ 92 u8 *aRow; /* Data for the current row, if all on one page */ 93 }; 94 typedef struct VdbeCursor VdbeCursor; 95 96 /* 97 ** A value for VdbeCursor.cacheValid that means the cache is always invalid. 98 */ 99 #define CACHE_STALE 0 100 101 /* 102 ** Internally, the vdbe manipulates nearly all SQL values as Mem 103 ** structures. Each Mem struct may cache multiple representations (string, 104 ** integer etc.) of the same value. A value (and therefore Mem structure) 105 ** has the following properties: 106 ** 107 ** Each value has a manifest type. The manifest type of the value stored 108 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 109 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 110 ** SQLITE_BLOB. 111 */ 112 struct Mem { 113 union { 114 i64 i; /* Integer value. */ 115 int nZero; /* Used when bit MEM_Zero is set in flags */ 116 FuncDef *pDef; /* Used only when flags==MEM_Agg */ 117 RowSet *pRowSet; /* Used only when flags==MEM_RowSet */ 118 } u; 119 double r; /* Real value */ 120 sqlite3 *db; /* The associated database connection */ 121 char *z; /* String or BLOB value */ 122 int n; /* Number of characters in string value, excluding '\0' */ 123 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 124 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ 125 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ 126 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 127 char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */ 128 }; 129 130 /* One or more of the following flags are set to indicate the validOK 131 ** representations of the value stored in the Mem struct. 132 ** 133 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 134 ** No other flags may be set in this case. 135 ** 136 ** If the MEM_Str flag is set then Mem.z points at a string representation. 137 ** Usually this is encoded in the same unicode encoding as the main 138 ** database (see below for exceptions). If the MEM_Term flag is also 139 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 140 ** flags may coexist with the MEM_Str flag. 141 ** 142 ** Multiple of these values can appear in Mem.flags. But only one 143 ** at a time can appear in Mem.type. 144 */ 145 #define MEM_Null 0x0001 /* Value is NULL */ 146 #define MEM_Str 0x0002 /* Value is a string */ 147 #define MEM_Int 0x0004 /* Value is an integer */ 148 #define MEM_Real 0x0008 /* Value is a real number */ 149 #define MEM_Blob 0x0010 /* Value is a BLOB */ 150 #define MEM_RowSet 0x0020 /* Value is a RowSet object */ 151 #define MEM_TypeMask 0x00ff /* Mask of type bits */ 152 153 /* Whenever Mem contains a valid string or blob representation, one of 154 ** the following flags must be set to determine the memory management 155 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 156 ** string is \000 or \u0000 terminated 157 */ 158 #define MEM_Term 0x0200 /* String rep is nul terminated */ 159 #define MEM_Dyn 0x0400 /* Need to call sqliteFree() on Mem.z */ 160 #define MEM_Static 0x0800 /* Mem.z points to a static string */ 161 #define MEM_Ephem 0x1000 /* Mem.z points to an ephemeral string */ 162 #define MEM_Agg 0x2000 /* Mem.z points to an agg function context */ 163 #define MEM_Zero 0x4000 /* Mem.i contains count of 0s appended to blob */ 164 165 #ifdef SQLITE_OMIT_INCRBLOB 166 #undef MEM_Zero 167 #define MEM_Zero 0x0000 168 #endif 169 170 171 /* 172 ** Clear any existing type flags from a Mem and replace them with f 173 */ 174 #define MemSetTypeFlag(p, f) \ 175 ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f) 176 177 178 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 179 ** additional information about auxiliary information bound to arguments 180 ** of the function. This is used to implement the sqlite3_get_auxdata() 181 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 182 ** that can be associated with a constant argument to a function. This 183 ** allows functions such as "regexp" to compile their constant regular 184 ** expression argument once and reused the compiled code for multiple 185 ** invocations. 186 */ 187 struct VdbeFunc { 188 FuncDef *pFunc; /* The definition of the function */ 189 int nAux; /* Number of entries allocated for apAux[] */ 190 struct AuxData { 191 void *pAux; /* Aux data for the i-th argument */ 192 void (*xDelete)(void *); /* Destructor for the aux data */ 193 } apAux[1]; /* One slot for each function argument */ 194 }; 195 196 /* 197 ** The "context" argument for a installable function. A pointer to an 198 ** instance of this structure is the first argument to the routines used 199 ** implement the SQL functions. 200 ** 201 ** There is a typedef for this structure in sqlite.h. So all routines, 202 ** even the public interface to SQLite, can use a pointer to this structure. 203 ** But this file is the only place where the internal details of this 204 ** structure are known. 205 ** 206 ** This structure is defined inside of vdbeInt.h because it uses substructures 207 ** (Mem) which are only defined there. 208 */ 209 struct sqlite3_context { 210 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 211 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 212 Mem s; /* The return value is stored here */ 213 Mem *pMem; /* Memory cell used to store aggregate context */ 214 int isError; /* Error code returned by the function. */ 215 CollSeq *pColl; /* Collating sequence */ 216 }; 217 218 /* 219 ** A Set structure is used for quick testing to see if a value 220 ** is part of a small set. Sets are used to implement code like 221 ** this: 222 ** x.y IN ('hi','hoo','hum') 223 */ 224 typedef struct Set Set; 225 struct Set { 226 Hash hash; /* A set is just a hash table */ 227 HashElem *prev; /* Previously accessed hash elemen */ 228 }; 229 230 /* 231 ** A Context stores the last insert rowid, the last statement change count, 232 ** and the current statement change count (i.e. changes since last statement). 233 ** The current keylist is also stored in the context. 234 ** Elements of Context structure type make up the ContextStack, which is 235 ** updated by the ContextPush and ContextPop opcodes (used by triggers). 236 ** The context is pushed before executing a trigger a popped when the 237 ** trigger finishes. 238 */ 239 typedef struct Context Context; 240 struct Context { 241 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 242 int nChange; /* Statement changes (Vdbe.nChanges) */ 243 }; 244 245 /* 246 ** An instance of the virtual machine. This structure contains the complete 247 ** state of the virtual machine. 248 ** 249 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 250 ** is really a pointer to an instance of this structure. 251 ** 252 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 253 ** any virtual table method invocations made by the vdbe program. It is 254 ** set to 2 for xDestroy method calls and 1 for all other methods. This 255 ** variable is used for two purposes: to allow xDestroy methods to execute 256 ** "DROP TABLE" statements and to prevent some nasty side effects of 257 ** malloc failure when SQLite is invoked recursively by a virtual table 258 ** method function. 259 */ 260 struct Vdbe { 261 sqlite3 *db; /* The whole database */ 262 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 263 int nOp; /* Number of instructions in the program */ 264 int nOpAlloc; /* Number of slots allocated for aOp[] */ 265 Op *aOp; /* Space to hold the virtual machine's program */ 266 int nLabel; /* Number of labels used */ 267 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 268 int *aLabel; /* Space to hold the labels */ 269 Mem **apArg; /* Arguments to currently executing user function */ 270 Mem *aColName; /* Column names to return */ 271 int nCursor; /* Number of slots in apCsr[] */ 272 VdbeCursor **apCsr; /* One element of this array for each open cursor */ 273 int nVar; /* Number of entries in aVar[] */ 274 Mem *aVar; /* Values for the OP_Variable opcode. */ 275 char **azVar; /* Name of variables */ 276 int okVar; /* True if azVar[] has been initialized */ 277 u32 magic; /* Magic number for sanity checking */ 278 int nMem; /* Number of memory locations currently allocated */ 279 Mem *aMem; /* The memory locations */ 280 int cacheCtr; /* VdbeCursor row cache generation counter */ 281 int contextStackTop; /* Index of top element in the context stack */ 282 int contextStackDepth; /* The size of the "context" stack */ 283 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 284 int pc; /* The program counter */ 285 int rc; /* Value to return */ 286 int errorAction; /* Recovery action to do in case of an error */ 287 int nResColumn; /* Number of columns in one row of the result set */ 288 char **azResColumn; /* Values for one row of result */ 289 char *zErrMsg; /* Error message written here */ 290 Mem *pResultSet; /* Pointer to an array of results */ 291 u8 explain; /* True if EXPLAIN present on SQL command */ 292 u8 changeCntOn; /* True to update the change-counter */ 293 u8 expired; /* True if the VM needs to be recompiled */ 294 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 295 u8 inVtabMethod; /* See comments above */ 296 u8 usesStmtJournal; /* True if uses a statement journal */ 297 u8 readOnly; /* True for read-only statements */ 298 u8 isPrepareV2; /* True if prepared with prepare_v2() */ 299 int nChange; /* Number of db changes made since last reset */ 300 i64 startTime; /* Time when query started - used for profiling */ 301 int btreeMask; /* Bitmask of db->aDb[] entries referenced */ 302 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */ 303 int aCounter[2]; /* Counters used by sqlite3_stmt_status() */ 304 char *zSql; /* Text of the SQL statement that generated this */ 305 void *pFree; /* Free this when deleting the vdbe */ 306 #ifdef SQLITE_DEBUG 307 FILE *trace; /* Write an execution trace here, if not NULL */ 308 #endif 309 int iStatement; /* Statement number (or 0 if has not opened stmt) */ 310 #ifdef SQLITE_SSE 311 int fetchId; /* Statement number used by sqlite3_fetch_statement */ 312 int lru; /* Counter used for LRU cache replacement */ 313 #endif 314 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 315 Vdbe *pLruPrev; 316 Vdbe *pLruNext; 317 #endif 318 }; 319 320 /* 321 ** The following are allowed values for Vdbe.magic 322 */ 323 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 324 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 325 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 326 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 327 328 /* 329 ** Function prototypes 330 */ 331 void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*); 332 void sqliteVdbePopStack(Vdbe*,int); 333 int sqlite3VdbeCursorMoveto(VdbeCursor*); 334 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 335 void sqlite3VdbePrintOp(FILE*, int, Op*); 336 #endif 337 int sqlite3VdbeSerialTypeLen(u32); 338 u32 sqlite3VdbeSerialType(Mem*, int); 339 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 340 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 341 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 342 343 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 344 int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*); 345 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 346 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 347 int sqlite3VdbeExec(Vdbe*); 348 int sqlite3VdbeList(Vdbe*); 349 int sqlite3VdbeHalt(Vdbe*); 350 int sqlite3VdbeChangeEncoding(Mem *, int); 351 int sqlite3VdbeMemTooBig(Mem*); 352 int sqlite3VdbeMemCopy(Mem*, const Mem*); 353 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 354 void sqlite3VdbeMemMove(Mem*, Mem*); 355 int sqlite3VdbeMemNulTerminate(Mem*); 356 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 357 void sqlite3VdbeMemSetInt64(Mem*, i64); 358 void sqlite3VdbeMemSetDouble(Mem*, double); 359 void sqlite3VdbeMemSetNull(Mem*); 360 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 361 void sqlite3VdbeMemSetRowSet(Mem*); 362 int sqlite3VdbeMemMakeWriteable(Mem*); 363 int sqlite3VdbeMemStringify(Mem*, int); 364 i64 sqlite3VdbeIntValue(Mem*); 365 int sqlite3VdbeMemIntegerify(Mem*); 366 double sqlite3VdbeRealValue(Mem*); 367 void sqlite3VdbeIntegerAffinity(Mem*); 368 int sqlite3VdbeMemRealify(Mem*); 369 int sqlite3VdbeMemNumerify(Mem*); 370 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 371 void sqlite3VdbeMemRelease(Mem *p); 372 void sqlite3VdbeMemReleaseExternal(Mem *p); 373 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 374 const char *sqlite3OpcodeName(int); 375 int sqlite3VdbeOpcodeHasProperty(int, int); 376 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve); 377 int sqlite3VdbeCloseStatement(Vdbe *, int); 378 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 379 int sqlite3VdbeReleaseBuffers(Vdbe *p); 380 #endif 381 382 #ifndef SQLITE_OMIT_SHARED_CACHE 383 void sqlite3VdbeMutexArrayEnter(Vdbe *p); 384 #else 385 # define sqlite3VdbeMutexArrayEnter(p) 386 #endif 387 388 int sqlite3VdbeMemTranslate(Mem*, u8); 389 #ifdef SQLITE_DEBUG 390 void sqlite3VdbePrintSql(Vdbe*); 391 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 392 #endif 393 int sqlite3VdbeMemHandleBom(Mem *pMem); 394 395 #ifndef SQLITE_OMIT_INCRBLOB 396 int sqlite3VdbeMemExpandBlob(Mem *); 397 #else 398 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK 399 #endif 400 401 #endif /* !defined(_VDBEINT_H_) */ 402