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 #ifndef _VDBEINT_H_ 19 #define _VDBEINT_H_ 20 21 /* 22 ** SQL is translated into a sequence of instructions to be 23 ** executed by a virtual machine. Each instruction is an instance 24 ** of the following structure. 25 */ 26 typedef struct VdbeOp Op; 27 28 /* 29 ** Boolean values 30 */ 31 typedef unsigned char Bool; 32 33 /* 34 ** A cursor is a pointer into a single BTree within a database file. 35 ** The cursor can seek to a BTree entry with a particular key, or 36 ** loop over all entries of the Btree. You can also insert new BTree 37 ** entries or retrieve the key or data from the entry that the cursor 38 ** is currently pointing to. 39 ** 40 ** Every cursor that the virtual machine has open is represented by an 41 ** instance of the following structure. 42 ** 43 ** If the VdbeCursor.isTriggerRow flag is set it means that this cursor is 44 ** really a single row that represents the NEW or OLD pseudo-table of 45 ** a row trigger. The data for the row is stored in VdbeCursor.pData and 46 ** the rowid is in VdbeCursor.iKey. 47 */ 48 struct VdbeCursor { 49 BtCursor *pCursor; /* The cursor structure of the backend */ 50 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ 51 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ 52 Bool zeroed; /* True if zeroed out and ready for reuse */ 53 Bool rowidIsValid; /* True if lastRowid is valid */ 54 Bool atFirst; /* True if pointing to first entry */ 55 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 56 Bool nullRow; /* True if pointing to a row with no data */ 57 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 58 Bool isTable; /* True if a table requiring integer keys */ 59 Bool isIndex; /* True if an index containing keys only - no data */ 60 Bool isOrdered; /* True if the underlying table is BTREE_UNORDERED */ 61 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 62 Btree *pBt; /* Separate file holding temporary table */ 63 int pseudoTableReg; /* Register holding pseudotable content. */ 64 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 65 int nField; /* Number of fields in the header */ 66 i64 seqCount; /* Sequence counter */ 67 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 68 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 69 70 /* Result of last sqlite3BtreeMoveto() done by an OP_NotExists or 71 ** OP_IsUnique opcode on this cursor. */ 72 int seekResult; 73 74 /* Cached information about the header for the data record that the 75 ** cursor is currently pointing to. Only valid if cacheStatus matches 76 ** Vdbe.cacheCtr. Vdbe.cacheCtr will never take on the value of 77 ** CACHE_STALE and so setting cacheStatus=CACHE_STALE guarantees that 78 ** the cache is out of date. 79 ** 80 ** aRow might point to (ephemeral) data for the current row, or it might 81 ** be NULL. 82 */ 83 u32 cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 84 int payloadSize; /* Total number of bytes in the record */ 85 u32 *aType; /* Type values for all entries in the record */ 86 u32 *aOffset; /* Cached offsets to the start of each columns data */ 87 u8 *aRow; /* Data for the current row, if all on one page */ 88 }; 89 typedef struct VdbeCursor VdbeCursor; 90 91 /* 92 ** When a sub-program is executed (OP_Program), a structure of this type 93 ** is allocated to store the current value of the program counter, as 94 ** well as the current memory cell array and various other frame specific 95 ** values stored in the Vdbe struct. When the sub-program is finished, 96 ** these values are copied back to the Vdbe from the VdbeFrame structure, 97 ** restoring the state of the VM to as it was before the sub-program 98 ** began executing. 99 ** 100 ** Frames are stored in a linked list headed at Vdbe.pParent. Vdbe.pParent 101 ** is the parent of the current frame, or zero if the current frame 102 ** is the main Vdbe program. 103 */ 104 typedef struct VdbeFrame VdbeFrame; 105 struct VdbeFrame { 106 Vdbe *v; /* VM this frame belongs to */ 107 int pc; /* Program Counter */ 108 Op *aOp; /* Program instructions */ 109 int nOp; /* Size of aOp array */ 110 Mem *aMem; /* Array of memory cells */ 111 int nMem; /* Number of entries in aMem */ 112 VdbeCursor **apCsr; /* Element of Vdbe cursors */ 113 u16 nCursor; /* Number of entries in apCsr */ 114 void *token; /* Copy of SubProgram.token */ 115 int nChildMem; /* Number of memory cells for child frame */ 116 int nChildCsr; /* Number of cursors for child frame */ 117 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 118 int nChange; /* Statement changes (Vdbe.nChanges) */ 119 VdbeFrame *pParent; /* Parent of this frame */ 120 }; 121 122 #define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))]) 123 124 /* 125 ** A value for VdbeCursor.cacheValid that means the cache is always invalid. 126 */ 127 #define CACHE_STALE 0 128 129 /* 130 ** Internally, the vdbe manipulates nearly all SQL values as Mem 131 ** structures. Each Mem struct may cache multiple representations (string, 132 ** integer etc.) of the same value. A value (and therefore Mem structure) 133 ** has the following properties: 134 ** 135 ** Each value has a manifest type. The manifest type of the value stored 136 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 137 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 138 ** SQLITE_BLOB. 139 */ 140 struct Mem { 141 union { 142 i64 i; /* Integer value. */ 143 int nZero; /* Used when bit MEM_Zero is set in flags */ 144 FuncDef *pDef; /* Used only when flags==MEM_Agg */ 145 RowSet *pRowSet; /* Used only when flags==MEM_RowSet */ 146 VdbeFrame *pFrame; /* Used when flags==MEM_Frame */ 147 } u; 148 double r; /* Real value */ 149 sqlite3 *db; /* The associated database connection */ 150 char *z; /* String or BLOB value */ 151 int n; /* Number of characters in string value, excluding '\0' */ 152 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 153 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ 154 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ 155 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 156 char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */ 157 }; 158 159 /* One or more of the following flags are set to indicate the validOK 160 ** representations of the value stored in the Mem struct. 161 ** 162 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 163 ** No other flags may be set in this case. 164 ** 165 ** If the MEM_Str flag is set then Mem.z points at a string representation. 166 ** Usually this is encoded in the same unicode encoding as the main 167 ** database (see below for exceptions). If the MEM_Term flag is also 168 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 169 ** flags may coexist with the MEM_Str flag. 170 ** 171 ** Multiple of these values can appear in Mem.flags. But only one 172 ** at a time can appear in Mem.type. 173 */ 174 #define MEM_Null 0x0001 /* Value is NULL */ 175 #define MEM_Str 0x0002 /* Value is a string */ 176 #define MEM_Int 0x0004 /* Value is an integer */ 177 #define MEM_Real 0x0008 /* Value is a real number */ 178 #define MEM_Blob 0x0010 /* Value is a BLOB */ 179 #define MEM_RowSet 0x0020 /* Value is a RowSet object */ 180 #define MEM_Frame 0x0040 /* Value is a VdbeFrame object */ 181 #define MEM_TypeMask 0x00ff /* Mask of type bits */ 182 183 /* Whenever Mem contains a valid string or blob representation, one of 184 ** the following flags must be set to determine the memory management 185 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 186 ** string is \000 or \u0000 terminated 187 */ 188 #define MEM_Term 0x0200 /* String rep is nul terminated */ 189 #define MEM_Dyn 0x0400 /* Need to call sqliteFree() on Mem.z */ 190 #define MEM_Static 0x0800 /* Mem.z points to a static string */ 191 #define MEM_Ephem 0x1000 /* Mem.z points to an ephemeral string */ 192 #define MEM_Agg 0x2000 /* Mem.z points to an agg function context */ 193 #define MEM_Zero 0x4000 /* Mem.i contains count of 0s appended to blob */ 194 195 #ifdef SQLITE_OMIT_INCRBLOB 196 #undef MEM_Zero 197 #define MEM_Zero 0x0000 198 #endif 199 200 201 /* 202 ** Clear any existing type flags from a Mem and replace them with f 203 */ 204 #define MemSetTypeFlag(p, f) \ 205 ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f) 206 207 208 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 209 ** additional information about auxiliary information bound to arguments 210 ** of the function. This is used to implement the sqlite3_get_auxdata() 211 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 212 ** that can be associated with a constant argument to a function. This 213 ** allows functions such as "regexp" to compile their constant regular 214 ** expression argument once and reused the compiled code for multiple 215 ** invocations. 216 */ 217 struct VdbeFunc { 218 FuncDef *pFunc; /* The definition of the function */ 219 int nAux; /* Number of entries allocated for apAux[] */ 220 struct AuxData { 221 void *pAux; /* Aux data for the i-th argument */ 222 void (*xDelete)(void *); /* Destructor for the aux data */ 223 } apAux[1]; /* One slot for each function argument */ 224 }; 225 226 /* 227 ** The "context" argument for a installable function. A pointer to an 228 ** instance of this structure is the first argument to the routines used 229 ** implement the SQL functions. 230 ** 231 ** There is a typedef for this structure in sqlite.h. So all routines, 232 ** even the public interface to SQLite, can use a pointer to this structure. 233 ** But this file is the only place where the internal details of this 234 ** structure are known. 235 ** 236 ** This structure is defined inside of vdbeInt.h because it uses substructures 237 ** (Mem) which are only defined there. 238 */ 239 struct sqlite3_context { 240 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 241 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 242 Mem s; /* The return value is stored here */ 243 Mem *pMem; /* Memory cell used to store aggregate context */ 244 int isError; /* Error code returned by the function. */ 245 CollSeq *pColl; /* Collating sequence */ 246 }; 247 248 /* 249 ** A Set structure is used for quick testing to see if a value 250 ** is part of a small set. Sets are used to implement code like 251 ** this: 252 ** x.y IN ('hi','hoo','hum') 253 */ 254 typedef struct Set Set; 255 struct Set { 256 Hash hash; /* A set is just a hash table */ 257 HashElem *prev; /* Previously accessed hash elemen */ 258 }; 259 260 /* 261 ** An instance of the virtual machine. This structure contains the complete 262 ** state of the virtual machine. 263 ** 264 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 265 ** is really a pointer to an instance of this structure. 266 ** 267 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 268 ** any virtual table method invocations made by the vdbe program. It is 269 ** set to 2 for xDestroy method calls and 1 for all other methods. This 270 ** variable is used for two purposes: to allow xDestroy methods to execute 271 ** "DROP TABLE" statements and to prevent some nasty side effects of 272 ** malloc failure when SQLite is invoked recursively by a virtual table 273 ** method function. 274 */ 275 struct Vdbe { 276 sqlite3 *db; /* The database connection that owns this statement */ 277 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 278 int nOp; /* Number of instructions in the program */ 279 int nOpAlloc; /* Number of slots allocated for aOp[] */ 280 Op *aOp; /* Space to hold the virtual machine's program */ 281 int nLabel; /* Number of labels used */ 282 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 283 int *aLabel; /* Space to hold the labels */ 284 Mem **apArg; /* Arguments to currently executing user function */ 285 Mem *aColName; /* Column names to return */ 286 Mem *pResultSet; /* Pointer to an array of results */ 287 u16 nResColumn; /* Number of columns in one row of the result set */ 288 u16 nCursor; /* Number of slots in apCsr[] */ 289 VdbeCursor **apCsr; /* One element of this array for each open cursor */ 290 u8 errorAction; /* Recovery action to do in case of an error */ 291 u8 okVar; /* True if azVar[] has been initialized */ 292 ynVar nVar; /* Number of entries in aVar[] */ 293 Mem *aVar; /* Values for the OP_Variable opcode. */ 294 char **azVar; /* Name of variables */ 295 u32 magic; /* Magic number for sanity checking */ 296 int nMem; /* Number of memory locations currently allocated */ 297 Mem *aMem; /* The memory locations */ 298 u32 cacheCtr; /* VdbeCursor row cache generation counter */ 299 int pc; /* The program counter */ 300 int rc; /* Value to return */ 301 char *zErrMsg; /* Error message written here */ 302 u8 explain; /* True if EXPLAIN present on SQL command */ 303 u8 changeCntOn; /* True to update the change-counter */ 304 u8 expired; /* True if the VM needs to be recompiled */ 305 u8 runOnlyOnce; /* Automatically expire on reset */ 306 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 307 u8 inVtabMethod; /* See comments above */ 308 u8 usesStmtJournal; /* True if uses a statement journal */ 309 u8 readOnly; /* True for read-only statements */ 310 u8 isPrepareV2; /* True if prepared with prepare_v2() */ 311 int nChange; /* Number of db changes made since last reset */ 312 int btreeMask; /* Bitmask of db->aDb[] entries referenced */ 313 i64 startTime; /* Time when query started - used for profiling */ 314 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */ 315 int aCounter[3]; /* Counters used by sqlite3_stmt_status() */ 316 char *zSql; /* Text of the SQL statement that generated this */ 317 void *pFree; /* Free this when deleting the vdbe */ 318 i64 nFkConstraint; /* Number of imm. FK constraints this VM */ 319 i64 nStmtDefCons; /* Number of def. constraints when stmt started */ 320 int iStatement; /* Statement number (or 0 if has not opened stmt) */ 321 #ifdef SQLITE_DEBUG 322 FILE *trace; /* Write an execution trace here, if not NULL */ 323 #endif 324 VdbeFrame *pFrame; /* Parent frame */ 325 int nFrame; /* Number of frames in pFrame list */ 326 u32 expmask; /* Binding to these vars invalidates VM */ 327 SubProgram *pProgram; /* Linked list of all sub-programs used by VM */ 328 }; 329 330 /* 331 ** The following are allowed values for Vdbe.magic 332 */ 333 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 334 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 335 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 336 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 337 338 /* 339 ** Function prototypes 340 */ 341 void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*); 342 void sqliteVdbePopStack(Vdbe*,int); 343 int sqlite3VdbeCursorMoveto(VdbeCursor*); 344 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 345 void sqlite3VdbePrintOp(FILE*, int, Op*); 346 #endif 347 u32 sqlite3VdbeSerialTypeLen(u32); 348 u32 sqlite3VdbeSerialType(Mem*, int); 349 u32 sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 350 u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 351 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 352 353 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 354 int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*); 355 int sqlite3VdbeIdxRowid(sqlite3*, BtCursor *, i64 *); 356 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 357 int sqlite3VdbeExec(Vdbe*); 358 int sqlite3VdbeList(Vdbe*); 359 int sqlite3VdbeHalt(Vdbe*); 360 int sqlite3VdbeChangeEncoding(Mem *, int); 361 int sqlite3VdbeMemTooBig(Mem*); 362 int sqlite3VdbeMemCopy(Mem*, const Mem*); 363 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 364 void sqlite3VdbeMemMove(Mem*, Mem*); 365 int sqlite3VdbeMemNulTerminate(Mem*); 366 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 367 void sqlite3VdbeMemSetInt64(Mem*, i64); 368 #ifdef SQLITE_OMIT_FLOATING_POINT 369 # define sqlite3VdbeMemSetDouble sqlite3VdbeMemSetInt64 370 #else 371 void sqlite3VdbeMemSetDouble(Mem*, double); 372 #endif 373 void sqlite3VdbeMemSetNull(Mem*); 374 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 375 void sqlite3VdbeMemSetRowSet(Mem*); 376 int sqlite3VdbeMemMakeWriteable(Mem*); 377 int sqlite3VdbeMemStringify(Mem*, int); 378 i64 sqlite3VdbeIntValue(Mem*); 379 int sqlite3VdbeMemIntegerify(Mem*); 380 double sqlite3VdbeRealValue(Mem*); 381 void sqlite3VdbeIntegerAffinity(Mem*); 382 int sqlite3VdbeMemRealify(Mem*); 383 int sqlite3VdbeMemNumerify(Mem*); 384 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 385 void sqlite3VdbeMemRelease(Mem *p); 386 void sqlite3VdbeMemReleaseExternal(Mem *p); 387 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 388 const char *sqlite3OpcodeName(int); 389 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve); 390 int sqlite3VdbeCloseStatement(Vdbe *, int); 391 void sqlite3VdbeFrameDelete(VdbeFrame*); 392 int sqlite3VdbeFrameRestore(VdbeFrame *); 393 void sqlite3VdbeMemStoreType(Mem *pMem); 394 395 #ifndef SQLITE_OMIT_FOREIGN_KEY 396 int sqlite3VdbeCheckFk(Vdbe *, int); 397 #else 398 # define sqlite3VdbeCheckFk(p,i) 0 399 #endif 400 401 #ifndef SQLITE_OMIT_SHARED_CACHE 402 void sqlite3VdbeMutexArrayEnter(Vdbe *p); 403 #else 404 # define sqlite3VdbeMutexArrayEnter(p) 405 #endif 406 407 int sqlite3VdbeMemTranslate(Mem*, u8); 408 #ifdef SQLITE_DEBUG 409 void sqlite3VdbePrintSql(Vdbe*); 410 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 411 #endif 412 int sqlite3VdbeMemHandleBom(Mem *pMem); 413 414 #ifndef SQLITE_OMIT_INCRBLOB 415 int sqlite3VdbeMemExpandBlob(Mem *); 416 #else 417 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK 418 #endif 419 420 #endif /* !defined(_VDBEINT_H_) */ 421