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 1.164 2009/02/20 01:28:59 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 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 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 75 Btree *pBt; /* Separate file holding temporary table */ 76 int nData; /* Number of bytes in pData */ 77 char *pData; /* Data for a NEW or OLD pseudo-table */ 78 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ 79 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 80 int nField; /* Number of fields in the header */ 81 i64 seqCount; /* Sequence counter */ 82 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 83 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 84 85 /* Cached information about the header for the data record that the 86 ** cursor is currently pointing to. Only valid if cacheValid is true. 87 ** aRow might point to (ephemeral) data for the current row, or it might 88 ** be NULL. 89 */ 90 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 91 int payloadSize; /* Total number of bytes in the record */ 92 u32 *aType; /* Type values for all entries in the record */ 93 u32 *aOffset; /* Cached offsets to the start of each columns data */ 94 u8 *aRow; /* Data for the current row, if all on one page */ 95 }; 96 typedef struct VdbeCursor VdbeCursor; 97 98 /* 99 ** A value for VdbeCursor.cacheValid that means the cache is always invalid. 100 */ 101 #define CACHE_STALE 0 102 103 /* 104 ** Internally, the vdbe manipulates nearly all SQL values as Mem 105 ** structures. Each Mem struct may cache multiple representations (string, 106 ** integer etc.) of the same value. A value (and therefore Mem structure) 107 ** has the following properties: 108 ** 109 ** Each value has a manifest type. The manifest type of the value stored 110 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 111 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 112 ** SQLITE_BLOB. 113 */ 114 struct Mem { 115 union { 116 i64 i; /* Integer value. */ 117 int nZero; /* Used when bit MEM_Zero is set in flags */ 118 FuncDef *pDef; /* Used only when flags==MEM_Agg */ 119 RowSet *pRowSet; /* Used only when flags==MEM_RowSet */ 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 #define MEM_RowSet 0x0020 /* Value is a RowSet object */ 153 #define MEM_TypeMask 0x00ff /* Mask of type bits */ 154 155 /* Whenever Mem contains a valid string or blob representation, one of 156 ** the following flags must be set to determine the memory management 157 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 158 ** string is \000 or \u0000 terminated 159 */ 160 #define MEM_Term 0x0200 /* String rep is nul terminated */ 161 #define MEM_Dyn 0x0400 /* Need to call sqliteFree() on Mem.z */ 162 #define MEM_Static 0x0800 /* Mem.z points to a static string */ 163 #define MEM_Ephem 0x1000 /* Mem.z points to an ephemeral string */ 164 #define MEM_Agg 0x2000 /* Mem.z points to an agg function context */ 165 #define MEM_Zero 0x4000 /* Mem.i contains count of 0s appended to blob */ 166 167 #ifdef SQLITE_OMIT_INCRBLOB 168 #undef MEM_Zero 169 #define MEM_Zero 0x0000 170 #endif 171 172 173 /* 174 ** Clear any existing type flags from a Mem and replace them with f 175 */ 176 #define MemSetTypeFlag(p, f) \ 177 ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f) 178 179 180 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 181 ** additional information about auxiliary information bound to arguments 182 ** of the function. This is used to implement the sqlite3_get_auxdata() 183 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 184 ** that can be associated with a constant argument to a function. This 185 ** allows functions such as "regexp" to compile their constant regular 186 ** expression argument once and reused the compiled code for multiple 187 ** invocations. 188 */ 189 struct VdbeFunc { 190 FuncDef *pFunc; /* The definition of the function */ 191 int nAux; /* Number of entries allocated for apAux[] */ 192 struct AuxData { 193 void *pAux; /* Aux data for the i-th argument */ 194 void (*xDelete)(void *); /* Destructor for the aux data */ 195 } apAux[1]; /* One slot for each function argument */ 196 }; 197 198 /* 199 ** The "context" argument for a installable function. A pointer to an 200 ** instance of this structure is the first argument to the routines used 201 ** implement the SQL functions. 202 ** 203 ** There is a typedef for this structure in sqlite.h. So all routines, 204 ** even the public interface to SQLite, can use a pointer to this structure. 205 ** But this file is the only place where the internal details of this 206 ** structure are known. 207 ** 208 ** This structure is defined inside of vdbeInt.h because it uses substructures 209 ** (Mem) which are only defined there. 210 */ 211 struct sqlite3_context { 212 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 213 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 214 Mem s; /* The return value is stored here */ 215 Mem *pMem; /* Memory cell used to store aggregate context */ 216 int isError; /* Error code returned by the function. */ 217 CollSeq *pColl; /* Collating sequence */ 218 }; 219 220 /* 221 ** A Set structure is used for quick testing to see if a value 222 ** is part of a small set. Sets are used to implement code like 223 ** this: 224 ** x.y IN ('hi','hoo','hum') 225 */ 226 typedef struct Set Set; 227 struct Set { 228 Hash hash; /* A set is just a hash table */ 229 HashElem *prev; /* Previously accessed hash elemen */ 230 }; 231 232 /* 233 ** A Context stores the last insert rowid, the last statement change count, 234 ** and the current statement change count (i.e. changes since last statement). 235 ** The current keylist is also stored in the context. 236 ** Elements of Context structure type make up the ContextStack, which is 237 ** updated by the ContextPush and ContextPop opcodes (used by triggers). 238 ** The context is pushed before executing a trigger a popped when the 239 ** trigger finishes. 240 */ 241 typedef struct Context Context; 242 struct Context { 243 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 244 int nChange; /* Statement changes (Vdbe.nChanges) */ 245 }; 246 247 /* 248 ** An instance of the virtual machine. This structure contains the complete 249 ** state of the virtual machine. 250 ** 251 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 252 ** is really a pointer to an instance of this structure. 253 ** 254 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 255 ** any virtual table method invocations made by the vdbe program. It is 256 ** set to 2 for xDestroy method calls and 1 for all other methods. This 257 ** variable is used for two purposes: to allow xDestroy methods to execute 258 ** "DROP TABLE" statements and to prevent some nasty side effects of 259 ** malloc failure when SQLite is invoked recursively by a virtual table 260 ** method function. 261 */ 262 struct Vdbe { 263 sqlite3 *db; /* The whole database */ 264 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 265 int nOp; /* Number of instructions in the program */ 266 int nOpAlloc; /* Number of slots allocated for aOp[] */ 267 Op *aOp; /* Space to hold the virtual machine's program */ 268 int nLabel; /* Number of labels used */ 269 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 270 int *aLabel; /* Space to hold the labels */ 271 Mem **apArg; /* Arguments to currently executing user function */ 272 Mem *aColName; /* Column names to return */ 273 int nCursor; /* Number of slots in apCsr[] */ 274 VdbeCursor **apCsr; /* One element of this array for each open cursor */ 275 int nVar; /* Number of entries in aVar[] */ 276 Mem *aVar; /* Values for the OP_Variable opcode. */ 277 char **azVar; /* Name of variables */ 278 int okVar; /* True if azVar[] has been initialized */ 279 u32 magic; /* Magic number for sanity checking */ 280 int nMem; /* Number of memory locations currently allocated */ 281 Mem *aMem; /* The memory locations */ 282 int cacheCtr; /* VdbeCursor row cache generation counter */ 283 int contextStackTop; /* Index of top element in the context stack */ 284 int contextStackDepth; /* The size of the "context" stack */ 285 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 286 int pc; /* The program counter */ 287 int rc; /* Value to return */ 288 int errorAction; /* Recovery action to do in case of an error */ 289 int nResColumn; /* Number of columns in one row of the result set */ 290 char **azResColumn; /* Values for one row of result */ 291 char *zErrMsg; /* Error message written here */ 292 Mem *pResultSet; /* Pointer to an array of results */ 293 u8 explain; /* True if EXPLAIN present on SQL command */ 294 u8 changeCntOn; /* True to update the change-counter */ 295 u8 expired; /* True if the VM needs to be recompiled */ 296 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 297 u8 inVtabMethod; /* See comments above */ 298 u8 usesStmtJournal; /* True if uses a statement journal */ 299 u8 readOnly; /* True for read-only statements */ 300 u8 isPrepareV2; /* True if prepared with prepare_v2() */ 301 int nChange; /* Number of db changes made since last reset */ 302 i64 startTime; /* Time when query started - used for profiling */ 303 int btreeMask; /* Bitmask of db->aDb[] entries referenced */ 304 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */ 305 int aCounter[2]; /* Counters used by sqlite3_stmt_status() */ 306 char *zSql; /* Text of the SQL statement that generated this */ 307 void *pFree; /* Free this when deleting the vdbe */ 308 #ifdef SQLITE_DEBUG 309 FILE *trace; /* Write an execution trace here, if not NULL */ 310 #endif 311 int openedStatement; /* True if this VM has opened a statement journal */ 312 #ifdef SQLITE_SSE 313 int fetchId; /* Statement number used by sqlite3_fetch_statement */ 314 int lru; /* Counter used for LRU cache replacement */ 315 #endif 316 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 317 Vdbe *pLruPrev; 318 Vdbe *pLruNext; 319 #endif 320 }; 321 322 /* 323 ** The following are allowed values for Vdbe.magic 324 */ 325 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 326 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 327 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 328 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 329 330 /* 331 ** Function prototypes 332 */ 333 void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*); 334 void sqliteVdbePopStack(Vdbe*,int); 335 int sqlite3VdbeCursorMoveto(VdbeCursor*); 336 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 337 void sqlite3VdbePrintOp(FILE*, int, Op*); 338 #endif 339 int sqlite3VdbeSerialTypeLen(u32); 340 u32 sqlite3VdbeSerialType(Mem*, int); 341 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 342 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 343 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 344 345 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 346 int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*); 347 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 348 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 349 int sqlite3VdbeExec(Vdbe*); 350 int sqlite3VdbeList(Vdbe*); 351 int sqlite3VdbeHalt(Vdbe*); 352 int sqlite3VdbeChangeEncoding(Mem *, int); 353 int sqlite3VdbeMemTooBig(Mem*); 354 int sqlite3VdbeMemCopy(Mem*, const Mem*); 355 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 356 void sqlite3VdbeMemMove(Mem*, Mem*); 357 int sqlite3VdbeMemNulTerminate(Mem*); 358 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 359 void sqlite3VdbeMemSetInt64(Mem*, i64); 360 void sqlite3VdbeMemSetDouble(Mem*, double); 361 void sqlite3VdbeMemSetNull(Mem*); 362 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 363 void sqlite3VdbeMemSetRowSet(Mem*); 364 int sqlite3VdbeMemMakeWriteable(Mem*); 365 int sqlite3VdbeMemStringify(Mem*, int); 366 i64 sqlite3VdbeIntValue(Mem*); 367 int sqlite3VdbeMemIntegerify(Mem*); 368 double sqlite3VdbeRealValue(Mem*); 369 void sqlite3VdbeIntegerAffinity(Mem*); 370 int sqlite3VdbeMemRealify(Mem*); 371 int sqlite3VdbeMemNumerify(Mem*); 372 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 373 void sqlite3VdbeMemRelease(Mem *p); 374 void sqlite3VdbeMemReleaseExternal(Mem *p); 375 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 376 const char *sqlite3OpcodeName(int); 377 int sqlite3VdbeOpcodeHasProperty(int, int); 378 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve); 379 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 380 int sqlite3VdbeReleaseBuffers(Vdbe *p); 381 #endif 382 383 int sqlite3VdbeMemTranslate(Mem*, u8); 384 #ifdef SQLITE_DEBUG 385 void sqlite3VdbePrintSql(Vdbe*); 386 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 387 #endif 388 int sqlite3VdbeMemHandleBom(Mem *pMem); 389 390 #ifndef SQLITE_OMIT_INCRBLOB 391 int sqlite3VdbeMemExpandBlob(Mem *); 392 #else 393 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK 394 #endif 395 396 #endif /* !defined(_VDBEINT_H_) */ 397