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 struct VdbeCursor { 44 BtCursor *pCursor; /* The cursor structure of the backend */ 45 Btree *pBt; /* Separate file holding temporary table */ 46 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 47 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ 48 int pseudoTableReg; /* Register holding pseudotable content. */ 49 int nField; /* Number of fields in the header */ 50 Bool zeroed; /* True if zeroed out and ready for reuse */ 51 Bool rowidIsValid; /* True if lastRowid is valid */ 52 Bool atFirst; /* True if pointing to first entry */ 53 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 54 Bool nullRow; /* True if pointing to a row with no data */ 55 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 56 Bool isTable; /* True if a table requiring integer keys */ 57 Bool isIndex; /* True if an index containing keys only - no data */ 58 Bool isOrdered; /* True if the underlying table is BTREE_UNORDERED */ 59 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 60 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 61 i64 seqCount; /* Sequence counter */ 62 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 63 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ 64 65 /* Result of last sqlite3BtreeMoveto() done by an OP_NotExists or 66 ** OP_IsUnique opcode on this cursor. */ 67 int seekResult; 68 69 /* Cached information about the header for the data record that the 70 ** cursor is currently pointing to. Only valid if cacheStatus matches 71 ** Vdbe.cacheCtr. Vdbe.cacheCtr will never take on the value of 72 ** CACHE_STALE and so setting cacheStatus=CACHE_STALE guarantees that 73 ** the cache is out of date. 74 ** 75 ** aRow might point to (ephemeral) data for the current row, or it might 76 ** be NULL. 77 */ 78 u32 cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 79 int payloadSize; /* Total number of bytes in the record */ 80 u32 *aType; /* Type values for all entries in the record */ 81 u32 *aOffset; /* Cached offsets to the start of each columns data */ 82 u8 *aRow; /* Data for the current row, if all on one page */ 83 }; 84 typedef struct VdbeCursor VdbeCursor; 85 86 /* 87 ** When a sub-program is executed (OP_Program), a structure of this type 88 ** is allocated to store the current value of the program counter, as 89 ** well as the current memory cell array and various other frame specific 90 ** values stored in the Vdbe struct. When the sub-program is finished, 91 ** these values are copied back to the Vdbe from the VdbeFrame structure, 92 ** restoring the state of the VM to as it was before the sub-program 93 ** began executing. 94 ** 95 ** The memory for a VdbeFrame object is allocated and managed by a memory 96 ** cell in the parent (calling) frame. When the memory cell is deleted or 97 ** overwritten, the VdbeFrame object is not freed immediately. Instead, it 98 ** is linked into the Vdbe.pDelFrame list. The contents of the Vdbe.pDelFrame 99 ** list is deleted when the VM is reset in VdbeHalt(). The reason for doing 100 ** this instead of deleting the VdbeFrame immediately is to avoid recursive 101 ** calls to sqlite3VdbeMemRelease() when the memory cells belonging to the 102 ** child frame are released. 103 ** 104 ** The currently executing frame is stored in Vdbe.pFrame. Vdbe.pFrame is 105 ** set to NULL if the currently executing frame is the main program. 106 */ 107 typedef struct VdbeFrame VdbeFrame; 108 struct VdbeFrame { 109 Vdbe *v; /* VM this frame belongs to */ 110 int pc; /* Program Counter in parent (calling) frame */ 111 Op *aOp; /* Program instructions for parent frame */ 112 int nOp; /* Size of aOp array */ 113 Mem *aMem; /* Array of memory cells for parent frame */ 114 int nMem; /* Number of entries in aMem */ 115 VdbeCursor **apCsr; /* Array of Vdbe cursors for parent frame */ 116 u16 nCursor; /* Number of entries in apCsr */ 117 void *token; /* Copy of SubProgram.token */ 118 int nChildMem; /* Number of memory cells for child frame */ 119 int nChildCsr; /* Number of cursors for child frame */ 120 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 121 int nChange; /* Statement changes (Vdbe.nChanges) */ 122 VdbeFrame *pParent; /* Parent of this frame, or NULL if parent is main */ 123 }; 124 125 #define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))]) 126 127 /* 128 ** A value for VdbeCursor.cacheValid that means the cache is always invalid. 129 */ 130 #define CACHE_STALE 0 131 132 /* 133 ** Internally, the vdbe manipulates nearly all SQL values as Mem 134 ** structures. Each Mem struct may cache multiple representations (string, 135 ** integer etc.) of the same value. 136 */ 137 struct Mem { 138 sqlite3 *db; /* The associated database connection */ 139 char *z; /* String or BLOB value */ 140 double r; /* Real value */ 141 union { 142 i64 i; /* Integer value used when MEM_Int is set in flags */ 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 int n; /* Number of characters in string value, excluding '\0' */ 149 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 150 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ 151 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ 152 #ifdef SQLITE_DEBUG 153 Mem *pScopyFrom; /* This Mem is a shallow copy of pScopyFrom */ 154 void *pFiller; /* So that sizeof(Mem) is a multiple of 8 */ 155 #endif 156 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 157 char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */ 158 }; 159 160 /* One or more of the following flags are set to indicate the validOK 161 ** representations of the value stored in the Mem struct. 162 ** 163 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 164 ** No other flags may be set in this case. 165 ** 166 ** If the MEM_Str flag is set then Mem.z points at a string representation. 167 ** Usually this is encoded in the same unicode encoding as the main 168 ** database (see below for exceptions). If the MEM_Term flag is also 169 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 170 ** flags may coexist with the MEM_Str flag. 171 */ 172 #define MEM_Null 0x0001 /* Value is NULL */ 173 #define MEM_Str 0x0002 /* Value is a string */ 174 #define MEM_Int 0x0004 /* Value is an integer */ 175 #define MEM_Real 0x0008 /* Value is a real number */ 176 #define MEM_Blob 0x0010 /* Value is a BLOB */ 177 #define MEM_RowSet 0x0020 /* Value is a RowSet object */ 178 #define MEM_Frame 0x0040 /* Value is a VdbeFrame object */ 179 #define MEM_Invalid 0x0080 /* Value is undefined */ 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 #ifdef SQLITE_OMIT_INCRBLOB 194 #undef MEM_Zero 195 #define MEM_Zero 0x0000 196 #endif 197 198 /* 199 ** Clear any existing type flags from a Mem and replace them with f 200 */ 201 #define MemSetTypeFlag(p, f) \ 202 ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f) 203 204 /* 205 ** Return true if a memory cell is not marked as invalid. This macro 206 ** is for use inside assert() statements only. 207 */ 208 #ifdef SQLITE_DEBUG 209 #define memIsValid(M) ((M)->flags & MEM_Invalid)==0 210 #endif 211 212 213 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 214 ** additional information about auxiliary information bound to arguments 215 ** of the function. This is used to implement the sqlite3_get_auxdata() 216 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 217 ** that can be associated with a constant argument to a function. This 218 ** allows functions such as "regexp" to compile their constant regular 219 ** expression argument once and reused the compiled code for multiple 220 ** invocations. 221 */ 222 struct VdbeFunc { 223 FuncDef *pFunc; /* The definition of the function */ 224 int nAux; /* Number of entries allocated for apAux[] */ 225 struct AuxData { 226 void *pAux; /* Aux data for the i-th argument */ 227 void (*xDelete)(void *); /* Destructor for the aux data */ 228 } apAux[1]; /* One slot for each function argument */ 229 }; 230 231 /* 232 ** The "context" argument for a installable function. A pointer to an 233 ** instance of this structure is the first argument to the routines used 234 ** implement the SQL functions. 235 ** 236 ** There is a typedef for this structure in sqlite.h. So all routines, 237 ** even the public interface to SQLite, can use a pointer to this structure. 238 ** But this file is the only place where the internal details of this 239 ** structure are known. 240 ** 241 ** This structure is defined inside of vdbeInt.h because it uses substructures 242 ** (Mem) which are only defined there. 243 */ 244 struct sqlite3_context { 245 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 246 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 247 Mem s; /* The return value is stored here */ 248 Mem *pMem; /* Memory cell used to store aggregate context */ 249 int isError; /* Error code returned by the function. */ 250 CollSeq *pColl; /* Collating sequence */ 251 }; 252 253 /* 254 ** An instance of the virtual machine. This structure contains the complete 255 ** state of the virtual machine. 256 ** 257 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_prepare() 258 ** is really a pointer to an instance of this structure. 259 ** 260 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 261 ** any virtual table method invocations made by the vdbe program. It is 262 ** set to 2 for xDestroy method calls and 1 for all other methods. This 263 ** variable is used for two purposes: to allow xDestroy methods to execute 264 ** "DROP TABLE" statements and to prevent some nasty side effects of 265 ** malloc failure when SQLite is invoked recursively by a virtual table 266 ** method function. 267 */ 268 struct Vdbe { 269 sqlite3 *db; /* The database connection that owns this statement */ 270 Op *aOp; /* Space to hold the virtual machine's program */ 271 Mem *aMem; /* The memory locations */ 272 Mem **apArg; /* Arguments to currently executing user function */ 273 Mem *aColName; /* Column names to return */ 274 Mem *pResultSet; /* Pointer to an array of results */ 275 int nMem; /* Number of memory locations currently allocated */ 276 int nOp; /* Number of instructions in the program */ 277 int nOpAlloc; /* Number of slots allocated for aOp[] */ 278 int nLabel; /* Number of labels used */ 279 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 280 int *aLabel; /* Space to hold the labels */ 281 u16 nResColumn; /* Number of columns in one row of the result set */ 282 u16 nCursor; /* Number of slots in apCsr[] */ 283 u32 magic; /* Magic number for sanity checking */ 284 char *zErrMsg; /* Error message written here */ 285 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 286 VdbeCursor **apCsr; /* One element of this array for each open cursor */ 287 Mem *aVar; /* Values for the OP_Variable opcode. */ 288 char **azVar; /* Name of variables */ 289 ynVar nVar; /* Number of entries in aVar[] */ 290 u32 cacheCtr; /* VdbeCursor row cache generation counter */ 291 int pc; /* The program counter */ 292 int rc; /* Value to return */ 293 u8 errorAction; /* Recovery action to do in case of an error */ 294 u8 okVar; /* True if azVar[] has been initialized */ 295 u8 explain; /* True if EXPLAIN present on SQL command */ 296 u8 changeCntOn; /* True to update the change-counter */ 297 u8 expired; /* True if the VM needs to be recompiled */ 298 u8 runOnlyOnce; /* Automatically expire on reset */ 299 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 300 u8 inVtabMethod; /* See comments above */ 301 u8 usesStmtJournal; /* True if uses a statement journal */ 302 u8 readOnly; /* True for read-only statements */ 303 u8 isPrepareV2; /* True if prepared with prepare_v2() */ 304 int nChange; /* Number of db changes made since last reset */ 305 yDbMask btreeMask; /* Bitmask of db->aDb[] entries referenced */ 306 yDbMask lockMask; /* Subset of btreeMask that requires a lock */ 307 int iStatement; /* Statement number (or 0 if has not opened stmt) */ 308 int aCounter[3]; /* Counters used by sqlite3_stmt_status() */ 309 #ifndef SQLITE_OMIT_TRACE 310 i64 startTime; /* Time when query started - used for profiling */ 311 #endif 312 i64 nFkConstraint; /* Number of imm. FK constraints this VM */ 313 i64 nStmtDefCons; /* Number of def. constraints when stmt started */ 314 char *zSql; /* Text of the SQL statement that generated this */ 315 void *pFree; /* Free this when deleting the vdbe */ 316 #ifdef SQLITE_DEBUG 317 FILE *trace; /* Write an execution trace here, if not NULL */ 318 #endif 319 VdbeFrame *pFrame; /* Parent frame */ 320 VdbeFrame *pDelFrame; /* List of frame objects to free on VM reset */ 321 int nFrame; /* Number of frames in pFrame list */ 322 u32 expmask; /* Binding to these vars invalidates VM */ 323 SubProgram *pProgram; /* Linked list of all sub-programs used by VM */ 324 }; 325 326 /* 327 ** The following are allowed values for Vdbe.magic 328 */ 329 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 330 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 331 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 332 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 333 334 /* 335 ** Function prototypes 336 */ 337 void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*); 338 void sqliteVdbePopStack(Vdbe*,int); 339 int sqlite3VdbeCursorMoveto(VdbeCursor*); 340 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 341 void sqlite3VdbePrintOp(FILE*, int, Op*); 342 #endif 343 u32 sqlite3VdbeSerialTypeLen(u32); 344 u32 sqlite3VdbeSerialType(Mem*, int); 345 u32 sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 346 u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 347 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 348 349 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 350 int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*); 351 int sqlite3VdbeIdxRowid(sqlite3*, BtCursor *, i64 *); 352 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 353 int sqlite3VdbeExec(Vdbe*); 354 int sqlite3VdbeList(Vdbe*); 355 int sqlite3VdbeHalt(Vdbe*); 356 int sqlite3VdbeChangeEncoding(Mem *, int); 357 int sqlite3VdbeMemTooBig(Mem*); 358 int sqlite3VdbeMemCopy(Mem*, const Mem*); 359 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 360 void sqlite3VdbeMemMove(Mem*, Mem*); 361 int sqlite3VdbeMemNulTerminate(Mem*); 362 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 363 void sqlite3VdbeMemSetInt64(Mem*, i64); 364 #ifdef SQLITE_OMIT_FLOATING_POINT 365 # define sqlite3VdbeMemSetDouble sqlite3VdbeMemSetInt64 366 #else 367 void sqlite3VdbeMemSetDouble(Mem*, double); 368 #endif 369 void sqlite3VdbeMemSetNull(Mem*); 370 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 371 void sqlite3VdbeMemSetRowSet(Mem*); 372 int sqlite3VdbeMemMakeWriteable(Mem*); 373 int sqlite3VdbeMemStringify(Mem*, int); 374 i64 sqlite3VdbeIntValue(Mem*); 375 int sqlite3VdbeMemIntegerify(Mem*); 376 double sqlite3VdbeRealValue(Mem*); 377 void sqlite3VdbeIntegerAffinity(Mem*); 378 int sqlite3VdbeMemRealify(Mem*); 379 int sqlite3VdbeMemNumerify(Mem*); 380 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 381 void sqlite3VdbeMemRelease(Mem *p); 382 void sqlite3VdbeMemReleaseExternal(Mem *p); 383 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 384 const char *sqlite3OpcodeName(int); 385 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve); 386 int sqlite3VdbeCloseStatement(Vdbe *, int); 387 void sqlite3VdbeFrameDelete(VdbeFrame*); 388 int sqlite3VdbeFrameRestore(VdbeFrame *); 389 void sqlite3VdbeMemStoreType(Mem *pMem); 390 391 #if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE>0 392 void sqlite3VdbeEnter(Vdbe*); 393 void sqlite3VdbeLeave(Vdbe*); 394 #else 395 # define sqlite3VdbeEnter(X) 396 # define sqlite3VdbeLeave(X) 397 #endif 398 399 #ifdef SQLITE_DEBUG 400 void sqlite3VdbeMemPrepareToChange(Vdbe*,Mem*); 401 #endif 402 403 #ifndef SQLITE_OMIT_FOREIGN_KEY 404 int sqlite3VdbeCheckFk(Vdbe *, int); 405 #else 406 # define sqlite3VdbeCheckFk(p,i) 0 407 #endif 408 409 int sqlite3VdbeMemTranslate(Mem*, u8); 410 #ifdef SQLITE_DEBUG 411 void sqlite3VdbePrintSql(Vdbe*); 412 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 413 #endif 414 int sqlite3VdbeMemHandleBom(Mem *pMem); 415 416 #ifndef SQLITE_OMIT_INCRBLOB 417 int sqlite3VdbeMemExpandBlob(Mem *); 418 #else 419 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK 420 #endif 421 422 #endif /* !defined(_VDBEINT_H_) */ 423