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 1.154 2008/08/13 19:11:48 drh Exp $ 19 */ 20 #ifndef _VDBEINT_H_ 21 #define _VDBEINT_H_ 22 23 /* 24 ** intToKey() and keyToInt() used to transform the rowid. But with 25 ** the latest versions of the design they are no-ops. 26 */ 27 #define keyToInt(X) (X) 28 #define intToKey(X) (X) 29 30 31 /* 32 ** SQL is translated into a sequence of instructions to be 33 ** executed by a virtual machine. Each instruction is an instance 34 ** of the following structure. 35 */ 36 typedef struct VdbeOp Op; 37 38 /* 39 ** Boolean values 40 */ 41 typedef unsigned char Bool; 42 43 /* 44 ** A cursor is a pointer into a single BTree within a database file. 45 ** The cursor can seek to a BTree entry with a particular key, or 46 ** loop over all entries of the Btree. You can also insert new BTree 47 ** entries or retrieve the key or data from the entry that the cursor 48 ** is currently pointing to. 49 ** 50 ** Every cursor that the virtual machine has open is represented by an 51 ** instance of the following structure. 52 ** 53 ** If the Cursor.isTriggerRow flag is set it means that this cursor is 54 ** really a single row that represents the NEW or OLD pseudo-table of 55 ** a row trigger. The data for the row is stored in Cursor.pData and 56 ** the rowid is in Cursor.iKey. 57 */ 58 struct Cursor { 59 BtCursor *pCursor; /* The cursor structure of the backend */ 60 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ 61 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ 62 i64 nextRowid; /* Next rowid returned by OP_NewRowid */ 63 Bool zeroed; /* True if zeroed out and ready for reuse */ 64 Bool rowidIsValid; /* True if lastRowid is valid */ 65 Bool atFirst; /* True if pointing to first entry */ 66 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 67 Bool nullRow; /* True if pointing to a row with no data */ 68 Bool nextRowidValid; /* True if the nextRowid field is valid */ 69 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ 70 Bool ephemPseudoTable; 71 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 72 Bool isTable; /* True if a table requiring integer keys */ 73 Bool isIndex; /* True if an index containing keys only - no data */ 74 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 75 Btree *pBt; /* Separate file holding temporary table */ 76 int nData; /* Number of bytes in pData */ 77 char *pData; /* Data for a NEW or OLD pseudo-table */ 78 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ 79 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 80 int nField; /* Number of fields in the header */ 81 i64 seqCount; /* Sequence counter */ 82 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 83 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 84 85 /* Cached information about the header for the data record that the 86 ** cursor is currently pointing to. Only valid if cacheValid is true. 87 ** aRow might point to (ephemeral) data for the current row, or it might 88 ** be NULL. 89 */ 90 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 91 int payloadSize; /* Total number of bytes in the record */ 92 u32 *aType; /* Type values for all entries in the record */ 93 u32 *aOffset; /* Cached offsets to the start of each columns data */ 94 u8 *aRow; /* Data for the current row, if all on one page */ 95 }; 96 typedef struct Cursor Cursor; 97 98 /* 99 ** A value for Cursor.cacheValid that means the cache is always invalid. 100 */ 101 #define CACHE_STALE 0 102 103 /* 104 ** Internally, the vdbe manipulates nearly all SQL values as Mem 105 ** structures. Each Mem struct may cache multiple representations (string, 106 ** integer etc.) of the same value. A value (and therefore Mem structure) 107 ** has the following properties: 108 ** 109 ** Each value has a manifest type. The manifest type of the value stored 110 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 111 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 112 ** SQLITE_BLOB. 113 */ 114 struct Mem { 115 union { 116 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */ 117 FuncDef *pDef; /* Used only when flags==MEM_Agg */ 118 } u; 119 double r; /* Real value */ 120 sqlite3 *db; /* The associated database connection */ 121 char *z; /* String or BLOB value */ 122 int n; /* Number of characters in string value, excluding '\0' */ 123 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 124 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ 125 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ 126 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 127 char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */ 128 }; 129 130 /* One or more of the following flags are set to indicate the validOK 131 ** representations of the value stored in the Mem struct. 132 ** 133 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 134 ** No other flags may be set in this case. 135 ** 136 ** If the MEM_Str flag is set then Mem.z points at a string representation. 137 ** Usually this is encoded in the same unicode encoding as the main 138 ** database (see below for exceptions). If the MEM_Term flag is also 139 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 140 ** flags may coexist with the MEM_Str flag. 141 ** 142 ** Multiple of these values can appear in Mem.flags. But only one 143 ** at a time can appear in Mem.type. 144 */ 145 #define MEM_Null 0x0001 /* Value is NULL */ 146 #define MEM_Str 0x0002 /* Value is a string */ 147 #define MEM_Int 0x0004 /* Value is an integer */ 148 #define MEM_Real 0x0008 /* Value is a real number */ 149 #define MEM_Blob 0x0010 /* Value is a BLOB */ 150 151 #define MemSetTypeFlag(p, f) \ 152 ((p)->flags = ((p)->flags&~(MEM_Int|MEM_Real|MEM_Null|MEM_Blob|MEM_Str))|f) 153 154 /* Whenever Mem contains a valid string or blob representation, one of 155 ** the following flags must be set to determine the memory management 156 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 157 ** string is \000 or \u0000 terminated 158 */ 159 #define MEM_Term 0x0020 /* String rep is nul terminated */ 160 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ 161 #define MEM_Static 0x0080 /* Mem.z points to a static string */ 162 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ 163 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */ 164 #define MEM_Zero 0x0800 /* Mem.i contains count of 0s appended to blob */ 165 166 #ifdef SQLITE_OMIT_INCRBLOB 167 #undef MEM_Zero 168 #define MEM_Zero 0x0000 169 #endif 170 171 172 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 173 ** additional information about auxiliary information bound to arguments 174 ** of the function. This is used to implement the sqlite3_get_auxdata() 175 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 176 ** that can be associated with a constant argument to a function. This 177 ** allows functions such as "regexp" to compile their constant regular 178 ** expression argument once and reused the compiled code for multiple 179 ** invocations. 180 */ 181 struct VdbeFunc { 182 FuncDef *pFunc; /* The definition of the function */ 183 int nAux; /* Number of entries allocated for apAux[] */ 184 struct AuxData { 185 void *pAux; /* Aux data for the i-th argument */ 186 void (*xDelete)(void *); /* Destructor for the aux data */ 187 } apAux[1]; /* One slot for each function argument */ 188 }; 189 190 /* 191 ** The "context" argument for a installable function. A pointer to an 192 ** instance of this structure is the first argument to the routines used 193 ** implement the SQL functions. 194 ** 195 ** There is a typedef for this structure in sqlite.h. So all routines, 196 ** even the public interface to SQLite, can use a pointer to this structure. 197 ** But this file is the only place where the internal details of this 198 ** structure are known. 199 ** 200 ** This structure is defined inside of vdbeInt.h because it uses substructures 201 ** (Mem) which are only defined there. 202 */ 203 struct sqlite3_context { 204 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 205 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 206 Mem s; /* The return value is stored here */ 207 Mem *pMem; /* Memory cell used to store aggregate context */ 208 int isError; /* Error code returned by the function. */ 209 CollSeq *pColl; /* Collating sequence */ 210 }; 211 212 /* 213 ** A Set structure is used for quick testing to see if a value 214 ** is part of a small set. Sets are used to implement code like 215 ** this: 216 ** x.y IN ('hi','hoo','hum') 217 */ 218 typedef struct Set Set; 219 struct Set { 220 Hash hash; /* A set is just a hash table */ 221 HashElem *prev; /* Previously accessed hash elemen */ 222 }; 223 224 /* 225 ** A FifoPage structure holds a single page of valves. Pages are arranged 226 ** in a list. 227 */ 228 typedef struct FifoPage FifoPage; 229 struct FifoPage { 230 int nSlot; /* Number of entries aSlot[] */ 231 int iWrite; /* Push the next value into this entry in aSlot[] */ 232 int iRead; /* Read the next value from this entry in aSlot[] */ 233 FifoPage *pNext; /* Next page in the fifo */ 234 i64 aSlot[1]; /* One or more slots for rowid values */ 235 }; 236 237 /* 238 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation 239 ** of that structure is private to this file. 240 ** 241 ** The Fifo structure describes the entire fifo. 242 */ 243 typedef struct Fifo Fifo; 244 struct Fifo { 245 int nEntry; /* Total number of entries */ 246 sqlite3 *db; /* The associated database connection */ 247 FifoPage *pFirst; /* First page on the list */ 248 FifoPage *pLast; /* Last page on the list */ 249 }; 250 251 /* 252 ** A Context stores the last insert rowid, the last statement change count, 253 ** and the current statement change count (i.e. changes since last statement). 254 ** The current keylist is also stored in the context. 255 ** Elements of Context structure type make up the ContextStack, which is 256 ** updated by the ContextPush and ContextPop opcodes (used by triggers). 257 ** The context is pushed before executing a trigger a popped when the 258 ** trigger finishes. 259 */ 260 typedef struct Context Context; 261 struct Context { 262 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 263 int nChange; /* Statement changes (Vdbe.nChanges) */ 264 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */ 265 }; 266 267 /* 268 ** An instance of the virtual machine. This structure contains the complete 269 ** state of the virtual machine. 270 ** 271 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 272 ** is really a pointer to an instance of this structure. 273 ** 274 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 275 ** any virtual table method invocations made by the vdbe program. It is 276 ** set to 2 for xDestroy method calls and 1 for all other methods. This 277 ** variable is used for two purposes: to allow xDestroy methods to execute 278 ** "DROP TABLE" statements and to prevent some nasty side effects of 279 ** malloc failure when SQLite is invoked recursively by a virtual table 280 ** method function. 281 */ 282 struct Vdbe { 283 sqlite3 *db; /* The whole database */ 284 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 285 int nOp; /* Number of instructions in the program */ 286 int nOpAlloc; /* Number of slots allocated for aOp[] */ 287 Op *aOp; /* Space to hold the virtual machine's program */ 288 int nLabel; /* Number of labels used */ 289 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 290 int *aLabel; /* Space to hold the labels */ 291 Mem **apArg; /* Arguments to currently executing user function */ 292 Mem *aColName; /* Column names to return */ 293 int nCursor; /* Number of slots in apCsr[] */ 294 Cursor **apCsr; /* One element of this array for each open cursor */ 295 int nVar; /* Number of entries in aVar[] */ 296 Mem *aVar; /* Values for the OP_Variable opcode. */ 297 char **azVar; /* Name of variables */ 298 int okVar; /* True if azVar[] has been initialized */ 299 int magic; /* Magic number for sanity checking */ 300 int nMem; /* Number of memory locations currently allocated */ 301 Mem *aMem; /* The memory locations */ 302 int nCallback; /* Number of callbacks invoked so far */ 303 int cacheCtr; /* Cursor row cache generation counter */ 304 Fifo sFifo; /* A list of ROWIDs */ 305 int contextStackTop; /* Index of top element in the context stack */ 306 int contextStackDepth; /* The size of the "context" stack */ 307 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 308 int pc; /* The program counter */ 309 int rc; /* Value to return */ 310 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */ 311 int errorAction; /* Recovery action to do in case of an error */ 312 int inTempTrans; /* True if temp database is transactioned */ 313 int nResColumn; /* Number of columns in one row of the result set */ 314 char **azResColumn; /* Values for one row of result */ 315 char *zErrMsg; /* Error message written here */ 316 Mem *pResultSet; /* Pointer to an array of results */ 317 u8 explain; /* True if EXPLAIN present on SQL command */ 318 u8 changeCntOn; /* True to update the change-counter */ 319 u8 expired; /* True if the VM needs to be recompiled */ 320 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 321 u8 inVtabMethod; /* See comments above */ 322 int nChange; /* Number of db changes made since last reset */ 323 i64 startTime; /* Time when query started - used for profiling */ 324 int btreeMask; /* Bitmask of db->aDb[] entries referenced */ 325 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */ 326 int nSql; /* Number of bytes in zSql */ 327 char *zSql; /* Text of the SQL statement that generated this */ 328 #ifdef SQLITE_DEBUG 329 FILE *trace; /* Write an execution trace here, if not NULL */ 330 #endif 331 int openedStatement; /* True if this VM has opened a statement journal */ 332 #ifdef SQLITE_SSE 333 int fetchId; /* Statement number used by sqlite3_fetch_statement */ 334 int lru; /* Counter used for LRU cache replacement */ 335 #endif 336 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 337 Vdbe *pLruPrev; 338 Vdbe *pLruNext; 339 #endif 340 }; 341 342 /* 343 ** The following are allowed values for Vdbe.magic 344 */ 345 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 346 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 347 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 348 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 349 350 /* 351 ** Function prototypes 352 */ 353 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*); 354 void sqliteVdbePopStack(Vdbe*,int); 355 int sqlite3VdbeCursorMoveto(Cursor*); 356 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 357 void sqlite3VdbePrintOp(FILE*, int, Op*); 358 #endif 359 int sqlite3VdbeSerialTypeLen(u32); 360 u32 sqlite3VdbeSerialType(Mem*, int); 361 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 362 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 363 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 364 365 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 366 int sqlite3VdbeIdxKeyCompare(Cursor*,UnpackedRecord*,int*); 367 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 368 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 369 int sqlite3VdbeExec(Vdbe*); 370 int sqlite3VdbeList(Vdbe*); 371 int sqlite3VdbeHalt(Vdbe*); 372 int sqlite3VdbeChangeEncoding(Mem *, int); 373 int sqlite3VdbeMemTooBig(Mem*); 374 int sqlite3VdbeMemCopy(Mem*, const Mem*); 375 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 376 void sqlite3VdbeMemMove(Mem*, Mem*); 377 int sqlite3VdbeMemNulTerminate(Mem*); 378 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 379 void sqlite3VdbeMemSetInt64(Mem*, i64); 380 void sqlite3VdbeMemSetDouble(Mem*, double); 381 void sqlite3VdbeMemSetNull(Mem*); 382 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 383 int sqlite3VdbeMemMakeWriteable(Mem*); 384 int sqlite3VdbeMemStringify(Mem*, int); 385 i64 sqlite3VdbeIntValue(Mem*); 386 int sqlite3VdbeMemIntegerify(Mem*); 387 double sqlite3VdbeRealValue(Mem*); 388 void sqlite3VdbeIntegerAffinity(Mem*); 389 int sqlite3VdbeMemRealify(Mem*); 390 int sqlite3VdbeMemNumerify(Mem*); 391 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 392 void sqlite3VdbeMemRelease(Mem *p); 393 void sqlite3VdbeMemReleaseExternal(Mem *p); 394 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 395 const char *sqlite3OpcodeName(int); 396 int sqlite3VdbeOpcodeHasProperty(int, int); 397 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve); 398 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT 399 int sqlite3VdbeReleaseBuffers(Vdbe *p); 400 #endif 401 402 #ifndef NDEBUG 403 void sqlite3VdbeMemSanity(Mem*); 404 #endif 405 int sqlite3VdbeMemTranslate(Mem*, u8); 406 #ifdef SQLITE_DEBUG 407 void sqlite3VdbePrintSql(Vdbe*); 408 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 409 #endif 410 int sqlite3VdbeMemHandleBom(Mem *pMem); 411 void sqlite3VdbeFifoInit(Fifo*, sqlite3*); 412 int sqlite3VdbeFifoPush(Fifo*, i64); 413 int sqlite3VdbeFifoPop(Fifo*, i64*); 414 void sqlite3VdbeFifoClear(Fifo*); 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