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never take on the value of 76 ** CACHE_STALE and so setting cacheStatus=CACHE_STALE guarantees that 77 ** the cache is out of date. 78 ** 79 ** aRow might point to (ephemeral) data for the current row, or it might 80 ** be NULL. 81 */ 82 u32 cacheStatus; /* Cache is valid if this matches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