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 pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ 60 Bool ephemPseudoTable; 61 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 62 Bool isTable; /* True if a table requiring integer keys */ 63 Bool isIndex; /* True if an index containing keys only - no data */ 64 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 65 Btree *pBt; /* Separate file holding temporary table */ 66 int nData; /* Number of bytes in pData */ 67 char *pData; /* Data for a NEW or OLD pseudo-table */ 68 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ 69 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 70 int nField; /* Number of fields in the header */ 71 i64 seqCount; /* Sequence counter */ 72 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 73 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 74 75 /* Result of last sqlite3BtreeMoveto() done by an OP_NotExists or 76 ** OP_IsUnique opcode on this cursor. */ 77 int seekResult; 78 79 /* Cached information about the header for the data record that the 80 ** cursor is currently pointing to. Only valid if cacheValid is true. 81 ** aRow might point to (ephemeral) data for the current row, or it might 82 ** be NULL. 83 */ 84 int 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 ** A value for VdbeCursor.cacheValid that means the cache is always invalid. 94 */ 95 #define CACHE_STALE 0 96 97 /* 98 ** Internally, the vdbe manipulates nearly all SQL values as Mem 99 ** structures. Each Mem struct may cache multiple representations (string, 100 ** integer etc.) of the same value. A value (and therefore Mem structure) 101 ** has the following properties: 102 ** 103 ** Each value has a manifest type. The manifest type of the value stored 104 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 105 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 106 ** SQLITE_BLOB. 107 */ 108 struct Mem { 109 union { 110 i64 i; /* Integer value. */ 111 int nZero; /* Used when bit MEM_Zero is set in flags */ 112 FuncDef *pDef; /* Used only when flags==MEM_Agg */ 113 RowSet *pRowSet; /* Used only when flags==MEM_RowSet */ 114 } u; 115 double r; /* Real value */ 116 sqlite3 *db; /* The associated database connection */ 117 char *z; /* String or BLOB value */ 118 int n; /* Number of characters in string value, excluding '\0' */ 119 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 120 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ 121 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ 122 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 123 char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */ 124 }; 125 126 /* One or more of the following flags are set to indicate the validOK 127 ** representations of the value stored in the Mem struct. 128 ** 129 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 130 ** No other flags may be set in this case. 131 ** 132 ** If the MEM_Str flag is set then Mem.z points at a string representation. 133 ** Usually this is encoded in the same unicode encoding as the main 134 ** database (see below for exceptions). If the MEM_Term flag is also 135 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 136 ** flags may coexist with the MEM_Str flag. 137 ** 138 ** Multiple of these values can appear in Mem.flags. But only one 139 ** at a time can appear in Mem.type. 140 */ 141 #define MEM_Null 0x0001 /* Value is NULL */ 142 #define MEM_Str 0x0002 /* Value is a string */ 143 #define MEM_Int 0x0004 /* Value is an integer */ 144 #define MEM_Real 0x0008 /* Value is a real number */ 145 #define MEM_Blob 0x0010 /* Value is a BLOB */ 146 #define MEM_RowSet 0x0020 /* Value is a RowSet object */ 147 #define MEM_TypeMask 0x00ff /* Mask of type bits */ 148 149 /* Whenever Mem contains a valid string or blob representation, one of 150 ** the following flags must be set to determine the memory management 151 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 152 ** string is \000 or \u0000 terminated 153 */ 154 #define MEM_Term 0x0200 /* String rep is nul terminated */ 155 #define MEM_Dyn 0x0400 /* Need to call sqliteFree() on Mem.z */ 156 #define MEM_Static 0x0800 /* Mem.z points to a static string */ 157 #define MEM_Ephem 0x1000 /* Mem.z points to an ephemeral string */ 158 #define MEM_Agg 0x2000 /* Mem.z points to an agg function context */ 159 #define MEM_Zero 0x4000 /* Mem.i contains count of 0s appended to blob */ 160 161 #ifdef SQLITE_OMIT_INCRBLOB 162 #undef MEM_Zero 163 #define MEM_Zero 0x0000 164 #endif 165 166 167 /* 168 ** Clear any existing type flags from a Mem and replace them with f 169 */ 170 #define MemSetTypeFlag(p, f) \ 171 ((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f) 172 173 174 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 175 ** additional information about auxiliary information bound to arguments 176 ** of the function. This is used to implement the sqlite3_get_auxdata() 177 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 178 ** that can be associated with a constant argument to a function. This 179 ** allows functions such as "regexp" to compile their constant regular 180 ** expression argument once and reused the compiled code for multiple 181 ** invocations. 182 */ 183 struct VdbeFunc { 184 FuncDef *pFunc; /* The definition of the function */ 185 int nAux; /* Number of entries allocated for apAux[] */ 186 struct AuxData { 187 void *pAux; /* Aux data for the i-th argument */ 188 void (*xDelete)(void *); /* Destructor for the aux data */ 189 } apAux[1]; /* One slot for each function argument */ 190 }; 191 192 /* 193 ** The "context" argument for a installable function. A pointer to an 194 ** instance of this structure is the first argument to the routines used 195 ** implement the SQL functions. 196 ** 197 ** There is a typedef for this structure in sqlite.h. So all routines, 198 ** even the public interface to SQLite, can use a pointer to this structure. 199 ** But this file is the only place where the internal details of this 200 ** structure are known. 201 ** 202 ** This structure is defined inside of vdbeInt.h because it uses substructures 203 ** (Mem) which are only defined there. 204 */ 205 struct sqlite3_context { 206 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 207 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 208 Mem s; /* The return value is stored here */ 209 Mem *pMem; /* Memory cell used to store aggregate context */ 210 int isError; /* Error code returned by the function. */ 211 CollSeq *pColl; /* Collating sequence */ 212 }; 213 214 /* 215 ** A Set structure is used for quick testing to see if a value 216 ** is part of a small set. Sets are used to implement code like 217 ** this: 218 ** x.y IN ('hi','hoo','hum') 219 */ 220 typedef struct Set Set; 221 struct Set { 222 Hash hash; /* A set is just a hash table */ 223 HashElem *prev; /* Previously accessed hash elemen */ 224 }; 225 226 /* 227 ** A Context stores the last insert rowid, the last statement change count, 228 ** and the current statement change count (i.e. changes since last statement). 229 ** The current keylist is also stored in the context. 230 ** Elements of Context structure type make up the ContextStack, which is 231 ** updated by the ContextPush and ContextPop opcodes (used by triggers). 232 ** The context is pushed before executing a trigger a popped when the 233 ** trigger finishes. 234 */ 235 typedef struct Context Context; 236 struct Context { 237 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 238 int nChange; /* Statement changes (Vdbe.nChanges) */ 239 }; 240 241 /* 242 ** An instance of the virtual machine. This structure contains the complete 243 ** state of the virtual machine. 244 ** 245 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 246 ** is really a pointer to an instance of this structure. 247 ** 248 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 249 ** any virtual table method invocations made by the vdbe program. It is 250 ** set to 2 for xDestroy method calls and 1 for all other methods. This 251 ** variable is used for two purposes: to allow xDestroy methods to execute 252 ** "DROP TABLE" statements and to prevent some nasty side effects of 253 ** malloc failure when SQLite is invoked recursively by a virtual table 254 ** method function. 255 */ 256 struct Vdbe { 257 sqlite3 *db; /* The database connection that owns this statement */ 258 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 259 int nOp; /* Number of instructions in the program */ 260 int nOpAlloc; /* Number of slots allocated for aOp[] */ 261 Op *aOp; /* Space to hold the virtual machine's program */ 262 int nLabel; /* Number of labels used */ 263 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 264 int *aLabel; /* Space to hold the labels */ 265 Mem **apArg; /* Arguments to currently executing user function */ 266 Mem *aColName; /* Column names to return */ 267 Mem *pResultSet; /* Pointer to an array of results */ 268 u16 nResColumn; /* Number of columns in one row of the result set */ 269 u16 nCursor; /* Number of slots in apCsr[] */ 270 VdbeCursor **apCsr; /* One element of this array for each open cursor */ 271 u8 errorAction; /* Recovery action to do in case of an error */ 272 u8 okVar; /* True if azVar[] has been initialized */ 273 u16 nVar; /* Number of entries in aVar[] */ 274 Mem *aVar; /* Values for the OP_Variable opcode. */ 275 char **azVar; /* Name of variables */ 276 u32 magic; /* Magic number for sanity checking */ 277 int nMem; /* Number of memory locations currently allocated */ 278 Mem *aMem; /* The memory locations */ 279 int cacheCtr; /* VdbeCursor row cache generation counter */ 280 int contextStackTop; /* Index of top element in the context stack */ 281 int contextStackDepth; /* The size of the "context" stack */ 282 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 283 int pc; /* The program counter */ 284 int rc; /* Value to return */ 285 char *zErrMsg; /* Error message written here */ 286 u8 explain; /* True if EXPLAIN present on SQL command */ 287 u8 changeCntOn; /* True to update the change-counter */ 288 u8 expired; /* True if the VM needs to be recompiled */ 289 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 290 u8 inVtabMethod; /* See comments above */ 291 u8 usesStmtJournal; /* True if uses a statement journal */ 292 u8 readOnly; /* True for read-only statements */ 293 u8 isPrepareV2; /* True if prepared with prepare_v2() */ 294 int nChange; /* Number of db changes made since last reset */ 295 int btreeMask; /* Bitmask of db->aDb[] entries referenced */ 296 i64 startTime; /* Time when query started - used for profiling */ 297 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */ 298 int aCounter[2]; /* Counters used by sqlite3_stmt_status() */ 299 char *zSql; /* Text of the SQL statement that generated this */ 300 void *pFree; /* Free this when deleting the vdbe */ 301 int iStatement; /* Statement number (or 0 if has not opened stmt) */ 302 #ifdef SQLITE_DEBUG 303 FILE *trace; /* Write an execution trace here, if not NULL */ 304 #endif 305 }; 306 307 /* 308 ** The following are allowed values for Vdbe.magic 309 */ 310 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 311 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 312 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 313 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 314 315 /* 316 ** Function prototypes 317 */ 318 void sqlite3VdbeFreeCursor(Vdbe *, VdbeCursor*); 319 void sqliteVdbePopStack(Vdbe*,int); 320 int sqlite3VdbeCursorMoveto(VdbeCursor*); 321 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 322 void sqlite3VdbePrintOp(FILE*, int, Op*); 323 #endif 324 u32 sqlite3VdbeSerialTypeLen(u32); 325 u32 sqlite3VdbeSerialType(Mem*, int); 326 u32 sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 327 u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 328 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 329 330 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 331 int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*); 332 int sqlite3VdbeIdxRowid(sqlite3*, BtCursor *, i64 *); 333 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 334 int sqlite3VdbeExec(Vdbe*); 335 int sqlite3VdbeList(Vdbe*); 336 int sqlite3VdbeHalt(Vdbe*); 337 int sqlite3VdbeChangeEncoding(Mem *, int); 338 int sqlite3VdbeMemTooBig(Mem*); 339 int sqlite3VdbeMemCopy(Mem*, const Mem*); 340 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 341 void sqlite3VdbeMemMove(Mem*, Mem*); 342 int sqlite3VdbeMemNulTerminate(Mem*); 343 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 344 void sqlite3VdbeMemSetInt64(Mem*, i64); 345 void sqlite3VdbeMemSetDouble(Mem*, double); 346 void sqlite3VdbeMemSetNull(Mem*); 347 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 348 void sqlite3VdbeMemSetRowSet(Mem*); 349 int sqlite3VdbeMemMakeWriteable(Mem*); 350 int sqlite3VdbeMemStringify(Mem*, int); 351 i64 sqlite3VdbeIntValue(Mem*); 352 int sqlite3VdbeMemIntegerify(Mem*); 353 double sqlite3VdbeRealValue(Mem*); 354 void sqlite3VdbeIntegerAffinity(Mem*); 355 int sqlite3VdbeMemRealify(Mem*); 356 int sqlite3VdbeMemNumerify(Mem*); 357 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 358 void sqlite3VdbeMemRelease(Mem *p); 359 void sqlite3VdbeMemReleaseExternal(Mem *p); 360 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 361 const char *sqlite3OpcodeName(int); 362 int sqlite3VdbeOpcodeHasProperty(int, int); 363 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve); 364 int sqlite3VdbeCloseStatement(Vdbe *, int); 365 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 366 int sqlite3VdbeReleaseBuffers(Vdbe *p); 367 #endif 368 369 #ifndef SQLITE_OMIT_SHARED_CACHE 370 void sqlite3VdbeMutexArrayEnter(Vdbe *p); 371 #else 372 # define sqlite3VdbeMutexArrayEnter(p) 373 #endif 374 375 int sqlite3VdbeMemTranslate(Mem*, u8); 376 #ifdef SQLITE_DEBUG 377 void sqlite3VdbePrintSql(Vdbe*); 378 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 379 #endif 380 int sqlite3VdbeMemHandleBom(Mem *pMem); 381 382 #ifndef SQLITE_OMIT_INCRBLOB 383 int sqlite3VdbeMemExpandBlob(Mem *); 384 #else 385 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK 386 #endif 387 388 #endif /* !defined(_VDBEINT_H_) */ 389