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 1.174 2009/06/23 14:15:04 drh Exp $ 19 */ 20 #ifndef _VDBEINT_H_ 21 #define _VDBEINT_H_ 22 23 /* 24 ** SQL is translated into a sequence of instructions to be 25 ** executed by a virtual machine. Each instruction is an instance 26 ** of the following structure. 27 */ 28 typedef struct VdbeOp Op; 29 30 /* 31 ** Boolean values 32 */ 33 typedef unsigned char Bool; 34 35 /* 36 ** A cursor is a pointer into a single BTree within a database file. 37 ** The cursor can seek to a BTree entry with a particular key, or 38 ** loop over all entries of the Btree. You can also insert new BTree 39 ** entries or retrieve the key or data from the entry that the cursor 40 ** is currently pointing to. 41 ** 42 ** Every cursor that the virtual machine has open is represented by an 43 ** instance of the following structure. 44 ** 45 ** If the VdbeCursor.isTriggerRow flag is set it means that this cursor is 46 ** really a single row that represents the NEW or OLD pseudo-table of 47 ** a row trigger. The data for the row is stored in VdbeCursor.pData and 48 ** the rowid is in VdbeCursor.iKey. 49 */ 50 struct VdbeCursor { 51 BtCursor *pCursor; /* The cursor structure of the backend */ 52 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ 53 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ 54 Bool zeroed; /* True if zeroed out and ready for reuse */ 55 Bool rowidIsValid; /* True if lastRowid is valid */ 56 Bool atFirst; /* True if pointing to first entry */ 57 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 58 Bool nullRow; /* True if pointing to a row with no data */ 59 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 60 Bool isTable; /* True if a table requiring integer keys */ 61 Bool isIndex; /* True if an index containing keys only - no data */ 62 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 63 Btree *pBt; /* Separate file holding temporary table */ 64 int pseudoTableReg; /* Register holding pseudotable content. */ 65 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 66 int nField; /* Number of fields in the header */ 67 i64 seqCount; /* Sequence counter */ 68 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 69 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 70 71 /* Result of last sqlite3BtreeMoveto() done by an OP_NotExists or 72 ** OP_IsUnique opcode on this cursor. */ 73 int seekResult; 74 75 /* Cached information about the header for the data record that the 76 ** cursor is currently pointing to. Only valid if cacheStatus matches 77 ** Vdbe.cacheCtr. Vdbe.cacheCtr will never take on the value of 78 ** CACHE_STALE and so setting cacheStatus=CACHE_STALE guarantees that 79 ** the cache is out of date. 80 ** 81 ** aRow might point to (ephemeral) data for the current row, or it might 82 ** be NULL. 83 */ 84 u32 cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 85 int payloadSize; /* Total number of bytes in the record */ 86 u32 *aType; /* Type values for all entries in the record */ 87 u32 *aOffset; /* Cached offsets to the start of each columns data */ 88 u8 *aRow; /* Data for the current row, if all on one page */ 89 }; 90 typedef struct VdbeCursor VdbeCursor; 91 92 /* 93 ** When a sub-program is executed (OP_Program), a structure of this type 94 ** is allocated to store the current value of the program counter, as 95 ** well as the current memory cell array and various other frame specific 96 ** values stored in the Vdbe struct. When the sub-program is finished, 97 ** these values are copied back to the Vdbe from the VdbeFrame structure, 98 ** restoring the state of the VM to as it was before the sub-program 99 ** began executing. 100 ** 101 ** Frames are stored in a linked list headed at Vdbe.pParent. Vdbe.pParent 102 ** is the parent of the current frame, or zero if the current frame 103 ** is the main Vdbe program. 104 */ 105 typedef struct VdbeFrame VdbeFrame; 106 struct VdbeFrame { 107 Vdbe *v; /* VM this frame belongs to */ 108 int pc; /* Program Counter */ 109 Op *aOp; /* Program instructions */ 110 int nOp; /* Size of aOp array */ 111 Mem *aMem; /* Array of memory cells */ 112 int nMem; /* Number of entries in aMem */ 113 VdbeCursor **apCsr; /* Element of Vdbe cursors */ 114 u16 nCursor; /* Number of entries in apCsr */ 115 void *token; /* Copy of SubProgram.token */ 116 int nChildMem; /* Number of memory cells for child frame */ 117 int nChildCsr; /* Number of cursors for child frame */ 118 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 119 int nChange; /* Statement changes (Vdbe.nChanges) */ 120 VdbeFrame *pParent; /* Parent of this frame */ 121 }; 122 123 #define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))]) 124 125 /* 126 ** A value for VdbeCursor.cacheValid that means the cache is always invalid. 127 */ 128 #define CACHE_STALE 0 129 130 /* 131 ** Internally, the vdbe manipulates nearly all SQL values as Mem 132 ** structures. Each Mem struct may cache multiple representations (string, 133 ** integer etc.) of the same value. A value (and therefore Mem structure) 134 ** has the following properties: 135 ** 136 ** Each value has a manifest type. The manifest type of the value stored 137 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 138 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 139 ** SQLITE_BLOB. 140 */ 141 struct Mem { 142 union { 143 i64 i; /* Integer value. */ 144 int nZero; /* Used when bit MEM_Zero is set in flags */ 145 FuncDef *pDef; /* Used only when flags==MEM_Agg */ 146 RowSet *pRowSet; /* Used only when flags==MEM_RowSet */ 147 VdbeFrame *pFrame; /* Used when flags==MEM_Frame */ 148 } u; 149 double r; /* Real value */ 150 sqlite3 *db; /* The associated database connection */ 151 char *z; /* String or BLOB value */ 152 int n; /* Number of characters in string value, excluding '\0' */ 153 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 154 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ 155 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ 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 ** Multiple of these values can appear in Mem.flags. But only one 173 ** at a time can appear in Mem.type. 174 */ 175 #define MEM_Null 0x0001 /* Value is NULL */ 176 #define MEM_Str 0x0002 /* Value is a string */ 177 #define MEM_Int 0x0004 /* Value is an integer */ 178 #define MEM_Real 0x0008 /* Value is a real number */ 179 #define MEM_Blob 0x0010 /* Value is a BLOB */ 180 #define MEM_RowSet 0x0020 /* Value is a RowSet object */ 181 #define MEM_Frame 0x0040 /* Value is a VdbeFrame object */ 182 #define MEM_TypeMask 0x00ff /* Mask of type bits */ 183 184 /* Whenever Mem contains a valid string or blob representation, one of 185 ** the following flags must be set to determine the memory management 186 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 187 ** string is \000 or \u0000 terminated 188 */ 189 #define MEM_Term 0x0200 /* String rep is nul terminated */ 190 #define MEM_Dyn 0x0400 /* Need to call sqliteFree() on Mem.z */ 191 #define MEM_Static 0x0800 /* Mem.z points to a static string */ 192 #define MEM_Ephem 0x1000 /* Mem.z points to an ephemeral string */ 193 #define MEM_Agg 0x2000 /* Mem.z points to an agg function context */ 194 #define MEM_Zero 0x4000 /* Mem.i contains count of 0s appended to blob */ 195 196 #ifdef SQLITE_OMIT_INCRBLOB 197 #undef MEM_Zero 198 #define MEM_Zero 0x0000 199 #endif 200 201 202 /* 203 ** Clear any existing type flags from a Mem and replace them with f 204 */ 205 #define MemSetTypeFlag(p, f) \ 206 ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f) 207 208 209 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 210 ** additional information about auxiliary information bound to arguments 211 ** of the function. This is used to implement the sqlite3_get_auxdata() 212 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 213 ** that can be associated with a constant argument to a function. This 214 ** allows functions such as "regexp" to compile their constant regular 215 ** expression argument once and reused the compiled code for multiple 216 ** invocations. 217 */ 218 struct VdbeFunc { 219 FuncDef *pFunc; /* The definition of the function */ 220 int nAux; /* Number of entries allocated for apAux[] */ 221 struct AuxData { 222 void *pAux; /* Aux data for the i-th argument */ 223 void (*xDelete)(void *); /* Destructor for the aux data */ 224 } apAux[1]; /* One slot for each function argument */ 225 }; 226 227 /* 228 ** The "context" argument for a installable function. A pointer to an 229 ** instance of this structure is the first argument to the routines used 230 ** implement the SQL functions. 231 ** 232 ** There is a typedef for this structure in sqlite.h. So all routines, 233 ** even the public interface to SQLite, can use a pointer to this structure. 234 ** But this file is the only place where the internal details of this 235 ** structure are known. 236 ** 237 ** This structure is defined inside of vdbeInt.h because it uses substructures 238 ** (Mem) which are only defined there. 239 */ 240 struct sqlite3_context { 241 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 242 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 243 Mem s; /* The return value is stored here */ 244 Mem *pMem; /* Memory cell used to store aggregate context */ 245 int isError; /* Error code returned by the function. */ 246 CollSeq *pColl; /* Collating sequence */ 247 }; 248 249 /* 250 ** A Set structure is used for quick testing to see if a value 251 ** is part of a small set. Sets are used to implement code like 252 ** this: 253 ** x.y IN ('hi','hoo','hum') 254 */ 255 typedef struct Set Set; 256 struct Set { 257 Hash hash; /* A set is just a hash table */ 258 HashElem *prev; /* Previously accessed hash elemen */ 259 }; 260 261 /* 262 ** An instance of the virtual machine. This structure contains the complete 263 ** state of the virtual machine. 264 ** 265 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 266 ** is really a pointer to an instance of this structure. 267 ** 268 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 269 ** any virtual table method invocations made by the vdbe program. It is 270 ** set to 2 for xDestroy method calls and 1 for all other methods. This 271 ** variable is used for two purposes: to allow xDestroy methods to execute 272 ** "DROP TABLE" statements and to prevent some nasty side effects of 273 ** malloc failure when SQLite is invoked recursively by a virtual table 274 ** method function. 275 */ 276 struct Vdbe { 277 sqlite3 *db; /* The database connection that owns this statement */ 278 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 279 int nOp; /* Number of instructions in the program */ 280 int nOpAlloc; /* Number of slots allocated for aOp[] */ 281 Op *aOp; /* Space to hold the virtual machine's program */ 282 int nLabel; /* Number of labels used */ 283 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 284 int *aLabel; /* Space to hold the labels */ 285 Mem **apArg; /* Arguments to currently executing user function */ 286 Mem *aColName; /* Column names to return */ 287 Mem *pResultSet; /* Pointer to an array of results */ 288 u16 nResColumn; /* Number of columns in one row of the result set */ 289 u16 nCursor; /* Number of slots in apCsr[] */ 290 VdbeCursor **apCsr; /* One element of this array for each open cursor */ 291 u8 errorAction; /* Recovery action to do in case of an error */ 292 u8 okVar; /* True if azVar[] has been initialized */ 293 u16 nVar; /* Number of entries in aVar[] */ 294 Mem *aVar; /* Values for the OP_Variable opcode. */ 295 char **azVar; /* Name of variables */ 296 u32 magic; /* Magic number for sanity checking */ 297 int nMem; /* Number of memory locations currently allocated */ 298 Mem *aMem; /* The memory locations */ 299 u32 cacheCtr; /* VdbeCursor row cache generation counter */ 300 int pc; /* The program counter */ 301 int rc; /* Value to return */ 302 char *zErrMsg; /* Error message written here */ 303 u8 explain; /* True if EXPLAIN present on SQL command */ 304 u8 changeCntOn; /* True to update the change-counter */ 305 u8 expired; /* True if the VM needs to be recompiled */ 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[2]; /* 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 u8 optimizable; /* True if VM may benefit from sqlite3_reoptimize() */ 327 u32 optmask; /* Bitmask of vars that may be used by reoptimize() */ 328 u32 expmask; /* Binding to these vars invalidates VM */ 329 }; 330 331 /* 332 ** The following are allowed values for Vdbe.magic 333 */ 334 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 335 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 336 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 337 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 338 339 /* 340 ** Function prototypes 341 */ 342 void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*); 343 void sqliteVdbePopStack(Vdbe*,int); 344 int sqlite3VdbeCursorMoveto(VdbeCursor*); 345 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 346 void sqlite3VdbePrintOp(FILE*, int, Op*); 347 #endif 348 u32 sqlite3VdbeSerialTypeLen(u32); 349 u32 sqlite3VdbeSerialType(Mem*, int); 350 u32 sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 351 u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 352 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 353 354 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 355 int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*); 356 int sqlite3VdbeIdxRowid(sqlite3*, BtCursor *, i64 *); 357 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 358 int sqlite3VdbeExec(Vdbe*); 359 int sqlite3VdbeList(Vdbe*); 360 int sqlite3VdbeHalt(Vdbe*); 361 int sqlite3VdbeChangeEncoding(Mem *, int); 362 int sqlite3VdbeMemTooBig(Mem*); 363 int sqlite3VdbeMemCopy(Mem*, const Mem*); 364 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 365 void sqlite3VdbeMemMove(Mem*, Mem*); 366 int sqlite3VdbeMemNulTerminate(Mem*); 367 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 368 void sqlite3VdbeMemSetInt64(Mem*, i64); 369 void sqlite3VdbeMemSetDouble(Mem*, double); 370 void sqlite3VdbeMemSetNull(Mem*); 371 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 372 void sqlite3VdbeMemSetRowSet(Mem*); 373 int sqlite3VdbeMemMakeWriteable(Mem*); 374 int sqlite3VdbeMemStringify(Mem*, int); 375 i64 sqlite3VdbeIntValue(Mem*); 376 int sqlite3VdbeMemIntegerify(Mem*); 377 double sqlite3VdbeRealValue(Mem*); 378 void sqlite3VdbeIntegerAffinity(Mem*); 379 int sqlite3VdbeMemRealify(Mem*); 380 int sqlite3VdbeMemNumerify(Mem*); 381 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 382 void sqlite3VdbeMemRelease(Mem *p); 383 void sqlite3VdbeMemReleaseExternal(Mem *p); 384 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 385 const char *sqlite3OpcodeName(int); 386 int sqlite3VdbeOpcodeHasProperty(int, int); 387 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve); 388 int sqlite3VdbeCloseStatement(Vdbe *, int); 389 void sqlite3VdbeFrameDelete(VdbeFrame*); 390 int sqlite3VdbeFrameRestore(VdbeFrame *); 391 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 392 int sqlite3VdbeReleaseBuffers(Vdbe *p); 393 #endif 394 void sqlite3VdbeMemStoreType(Mem *pMem); 395 396 #ifndef SQLITE_OMIT_FOREIGN_KEY 397 int sqlite3VdbeCheckFk(Vdbe *, int); 398 #else 399 # define sqlite3VdbeCheckFk(p,i) 0 400 #endif 401 402 #ifndef SQLITE_OMIT_SHARED_CACHE 403 void sqlite3VdbeMutexArrayEnter(Vdbe *p); 404 #else 405 # define sqlite3VdbeMutexArrayEnter(p) 406 #endif 407 408 int sqlite3VdbeMemTranslate(Mem*, u8); 409 #ifdef SQLITE_DEBUG 410 void sqlite3VdbePrintSql(Vdbe*); 411 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 412 #endif 413 int sqlite3VdbeMemHandleBom(Mem *pMem); 414 415 #ifndef SQLITE_OMIT_INCRBLOB 416 int sqlite3VdbeMemExpandBlob(Mem *); 417 #else 418 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK 419 #endif 420 421 #endif /* !defined(_VDBEINT_H_) */ 422