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 ** intToKey() and keyToInt() used to transform the rowid. But with 23 ** the latest versions of the design they are no-ops. 24 */ 25 #define keyToInt(X) (X) 26 #define intToKey(X) (X) 27 28 29 /* 30 ** SQL is translated into a sequence of instructions to be 31 ** executed by a virtual machine. Each instruction is an instance 32 ** of the following structure. 33 */ 34 typedef struct VdbeOp Op; 35 36 /* 37 ** Boolean values 38 */ 39 typedef unsigned char Bool; 40 41 /* 42 ** A cursor is a pointer into a single BTree within a database file. 43 ** The cursor can seek to a BTree entry with a particular key, or 44 ** loop over all entries of the Btree. You can also insert new BTree 45 ** entries or retrieve the key or data from the entry that the cursor 46 ** is currently pointing to. 47 ** 48 ** Every cursor that the virtual machine has open is represented by an 49 ** instance of the following structure. 50 ** 51 ** If the Cursor.isTriggerRow flag is set it means that this cursor is 52 ** really a single row that represents the NEW or OLD pseudo-table of 53 ** a row trigger. The data for the row is stored in Cursor.pData and 54 ** the rowid is in Cursor.iKey. 55 */ 56 struct Cursor { 57 BtCursor *pCursor; /* The cursor structure of the backend */ 58 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ 59 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ 60 i64 nextRowid; /* Next rowid returned by OP_NewRowid */ 61 Bool zeroed; /* True if zeroed out and ready for reuse */ 62 Bool rowidIsValid; /* True if lastRowid is valid */ 63 Bool atFirst; /* True if pointing to first entry */ 64 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 65 Bool nullRow; /* True if pointing to a row with no data */ 66 Bool nextRowidValid; /* True if the nextRowid field is valid */ 67 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ 68 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 69 Bool isTable; /* True if a table requiring integer keys */ 70 Bool isIndex; /* True if an index containing keys only - no data */ 71 u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */ 72 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 73 Btree *pBt; /* Separate file holding temporary table */ 74 int nData; /* Number of bytes in pData */ 75 char *pData; /* Data for a NEW or OLD pseudo-table */ 76 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ 77 u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */ 78 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 79 int nField; /* Number of fields in the header */ 80 i64 seqCount; /* Sequence counter */ 81 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 82 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 83 84 /* Cached information about the header for the data record that the 85 ** cursor is currently pointing to. Only valid if cacheValid is true. 86 ** aRow might point to (ephemeral) data for the current row, or it might 87 ** be NULL. 88 */ 89 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 90 int payloadSize; /* Total number of bytes in the record */ 91 u32 *aType; /* Type values for all entries in the record */ 92 u32 *aOffset; /* Cached offsets to the start of each columns data */ 93 u8 *aRow; /* Data for the current row, if all on one page */ 94 }; 95 typedef struct Cursor Cursor; 96 97 /* 98 ** Number of bytes of string storage space available to each stack 99 ** layer without having to malloc. NBFS is short for Number of Bytes 100 ** For Strings. 101 */ 102 #define NBFS 32 103 104 /* 105 ** A value for Cursor.cacheValid that means the cache is always invalid. 106 */ 107 #define CACHE_STALE 0 108 109 /* 110 ** Internally, the vdbe manipulates nearly all SQL values as Mem 111 ** structures. Each Mem struct may cache multiple representations (string, 112 ** integer etc.) of the same value. A value (and therefore Mem structure) 113 ** has the following properties: 114 ** 115 ** Each value has a manifest type. The manifest type of the value stored 116 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 117 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 118 ** SQLITE_BLOB. 119 */ 120 struct Mem { 121 union { 122 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */ 123 FuncDef *pDef; /* Used only when flags==MEM_Agg */ 124 } u; 125 double r; /* Real value */ 126 sqlite3 *db; /* The associated database connection */ 127 char *z; /* String or BLOB value */ 128 int n; /* Number of characters in string value, including '\0' */ 129 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 130 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ 131 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ 132 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 133 char zShort[NBFS]; /* Space for short strings */ 134 }; 135 typedef struct Mem Mem; 136 137 /* One or more of the following flags are set to indicate the validOK 138 ** representations of the value stored in the Mem struct. 139 ** 140 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 141 ** No other flags may be set in this case. 142 ** 143 ** If the MEM_Str flag is set then Mem.z points at a string representation. 144 ** Usually this is encoded in the same unicode encoding as the main 145 ** database (see below for exceptions). If the MEM_Term flag is also 146 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 147 ** flags may coexist with the MEM_Str flag. 148 ** 149 ** Multiple of these values can appear in Mem.flags. But only one 150 ** at a time can appear in Mem.type. 151 */ 152 #define MEM_Null 0x0001 /* Value is NULL */ 153 #define MEM_Str 0x0002 /* Value is a string */ 154 #define MEM_Int 0x0004 /* Value is an integer */ 155 #define MEM_Real 0x0008 /* Value is a real number */ 156 #define MEM_Blob 0x0010 /* Value is a BLOB */ 157 158 /* Whenever Mem contains a valid string or blob representation, one of 159 ** the following flags must be set to determine the memory management 160 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 161 ** string is \000 or \u0000 terminated 162 */ 163 #define MEM_Term 0x0020 /* String rep is nul terminated */ 164 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ 165 #define MEM_Static 0x0080 /* Mem.z points to a static string */ 166 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ 167 #define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */ 168 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */ 169 #define MEM_Zero 0x0800 /* Mem.i contains count of 0s appended to blob */ 170 171 #ifdef SQLITE_OMIT_INCRBLOB 172 #undef MEM_Zero 173 #define MEM_Zero 0x0000 174 #endif 175 176 177 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 178 ** additional information about auxiliary information bound to arguments 179 ** of the function. This is used to implement the sqlite3_get_auxdata() 180 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 181 ** that can be associated with a constant argument to a function. This 182 ** allows functions such as "regexp" to compile their constant regular 183 ** expression argument once and reused the compiled code for multiple 184 ** invocations. 185 */ 186 struct VdbeFunc { 187 FuncDef *pFunc; /* The definition of the function */ 188 int nAux; /* Number of entries allocated for apAux[] */ 189 struct AuxData { 190 void *pAux; /* Aux data for the i-th argument */ 191 void (*xDelete)(void *); /* Destructor for the aux data */ 192 } apAux[1]; /* One slot for each function argument */ 193 }; 194 typedef struct VdbeFunc VdbeFunc; 195 196 /* 197 ** The "context" argument for a installable function. A pointer to an 198 ** instance of this structure is the first argument to the routines used 199 ** implement the SQL functions. 200 ** 201 ** There is a typedef for this structure in sqlite.h. So all routines, 202 ** even the public interface to SQLite, can use a pointer to this structure. 203 ** But this file is the only place where the internal details of this 204 ** structure are known. 205 ** 206 ** This structure is defined inside of vdbeInt.h because it uses substructures 207 ** (Mem) which are only defined there. 208 */ 209 struct sqlite3_context { 210 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 211 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 212 Mem s; /* The return value is stored here */ 213 Mem *pMem; /* Memory cell used to store aggregate context */ 214 u8 isError; /* Set to true for an error */ 215 CollSeq *pColl; /* Collating sequence */ 216 }; 217 218 /* 219 ** A Set structure is used for quick testing to see if a value 220 ** is part of a small set. Sets are used to implement code like 221 ** this: 222 ** x.y IN ('hi','hoo','hum') 223 */ 224 typedef struct Set Set; 225 struct Set { 226 Hash hash; /* A set is just a hash table */ 227 HashElem *prev; /* Previously accessed hash elemen */ 228 }; 229 230 /* 231 ** A FifoPage structure holds a single page of valves. Pages are arranged 232 ** in a list. 233 */ 234 typedef struct FifoPage FifoPage; 235 struct FifoPage { 236 int nSlot; /* Number of entries aSlot[] */ 237 int iWrite; /* Push the next value into this entry in aSlot[] */ 238 int iRead; /* Read the next value from this entry in aSlot[] */ 239 FifoPage *pNext; /* Next page in the fifo */ 240 i64 aSlot[1]; /* One or more slots for rowid values */ 241 }; 242 243 /* 244 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation 245 ** of that structure is private to this file. 246 ** 247 ** The Fifo structure describes the entire fifo. 248 */ 249 typedef struct Fifo Fifo; 250 struct Fifo { 251 int nEntry; /* Total number of entries */ 252 FifoPage *pFirst; /* First page on the list */ 253 FifoPage *pLast; /* Last page on the list */ 254 }; 255 256 /* 257 ** A Context stores the last insert rowid, the last statement change count, 258 ** and the current statement change count (i.e. changes since last statement). 259 ** The current keylist is also stored in the context. 260 ** Elements of Context structure type make up the ContextStack, which is 261 ** updated by the ContextPush and ContextPop opcodes (used by triggers). 262 ** The context is pushed before executing a trigger a popped when the 263 ** trigger finishes. 264 */ 265 typedef struct Context Context; 266 struct Context { 267 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 268 int nChange; /* Statement changes (Vdbe.nChanges) */ 269 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */ 270 }; 271 272 /* 273 ** An instance of the virtual machine. This structure contains the complete 274 ** state of the virtual machine. 275 ** 276 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 277 ** is really a pointer to an instance of this structure. 278 ** 279 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 280 ** any virtual table method invocations made by the vdbe program. It is 281 ** set to 2 for xDestroy method calls and 1 for all other methods. This 282 ** variable is used for two purposes: to allow xDestroy methods to execute 283 ** "DROP TABLE" statements and to prevent some nasty side effects of 284 ** malloc failure when SQLite is invoked recursively by a virtual table 285 ** method function. 286 */ 287 struct Vdbe { 288 sqlite3 *db; /* The whole database */ 289 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 290 int nOp; /* Number of instructions in the program */ 291 int nOpAlloc; /* Number of slots allocated for aOp[] */ 292 Op *aOp; /* Space to hold the virtual machine's program */ 293 int nLabel; /* Number of labels used */ 294 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 295 int *aLabel; /* Space to hold the labels */ 296 Mem *aStack; /* The operand stack, except string values */ 297 Mem *pTos; /* Top entry in the operand stack */ 298 Mem **apArg; /* Arguments to currently executing user function */ 299 Mem *aColName; /* Column names to return */ 300 int nCursor; /* Number of slots in apCsr[] */ 301 Cursor **apCsr; /* One element of this array for each open cursor */ 302 int nVar; /* Number of entries in aVar[] */ 303 Mem *aVar; /* Values for the OP_Variable opcode. */ 304 char **azVar; /* Name of variables */ 305 int okVar; /* True if azVar[] has been initialized */ 306 int magic; /* Magic number for sanity checking */ 307 int nMem; /* Number of memory locations currently allocated */ 308 Mem *aMem; /* The memory locations */ 309 int nCallback; /* Number of callbacks invoked so far */ 310 int cacheCtr; /* Cursor row cache generation counter */ 311 Fifo sFifo; /* A list of ROWIDs */ 312 int contextStackTop; /* Index of top element in the context stack */ 313 int contextStackDepth; /* The size of the "context" stack */ 314 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 315 int pc; /* The program counter */ 316 int rc; /* Value to return */ 317 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */ 318 int errorAction; /* Recovery action to do in case of an error */ 319 int inTempTrans; /* True if temp database is transactioned */ 320 int returnStack[25]; /* Return address stack for OP_Gosub & OP_Return */ 321 int returnDepth; /* Next unused element in returnStack[] */ 322 int nResColumn; /* Number of columns in one row of the result set */ 323 char **azResColumn; /* Values for one row of result */ 324 int popStack; /* Pop the stack this much on entry to VdbeExec() */ 325 char *zErrMsg; /* Error message written here */ 326 u8 resOnStack; /* True if there are result values on the stack */ 327 u8 explain; /* True if EXPLAIN present on SQL command */ 328 u8 changeCntOn; /* True to update the change-counter */ 329 u8 aborted; /* True if ROLLBACK in another VM causes an abort */ 330 u8 expired; /* True if the VM needs to be recompiled */ 331 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 332 u8 inVtabMethod; /* See comments above */ 333 int nChange; /* Number of db changes made since last reset */ 334 i64 startTime; /* Time when query started - used for profiling */ 335 int btreeMask; /* Bitmask of db->aDb[] entries referenced */ 336 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */ 337 int nSql; /* Number of bytes in zSql */ 338 char *zSql; /* Text of the SQL statement that generated this */ 339 #ifdef SQLITE_DEBUG 340 FILE *trace; /* Write an execution trace here, if not NULL */ 341 #endif 342 int openedStatement; /* True if this VM has opened a statement journal */ 343 #ifdef SQLITE_SSE 344 int fetchId; /* Statement number used by sqlite3_fetch_statement */ 345 int lru; /* Counter used for LRU cache replacement */ 346 #endif 347 }; 348 349 /* 350 ** The following are allowed values for Vdbe.magic 351 */ 352 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 353 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 354 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 355 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 356 357 /* 358 ** Function prototypes 359 */ 360 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*); 361 void sqliteVdbePopStack(Vdbe*,int); 362 int sqlite3VdbeCursorMoveto(Cursor*); 363 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 364 void sqlite3VdbePrintOp(FILE*, int, Op*); 365 #endif 366 int sqlite3VdbeSerialTypeLen(u32); 367 u32 sqlite3VdbeSerialType(Mem*, int); 368 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 369 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 370 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 371 372 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 373 int sqlite3VdbeIdxKeyCompare(Cursor*,int,const unsigned char*,int*); 374 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 375 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 376 int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*); 377 int sqlite3VdbeIdxRowidLen(const u8*); 378 int sqlite3VdbeExec(Vdbe*); 379 int sqlite3VdbeList(Vdbe*); 380 int sqlite3VdbeHalt(Vdbe*); 381 int sqlite3VdbeChangeEncoding(Mem *, int); 382 int sqlite3VdbeMemTooBig(Mem*); 383 int sqlite3VdbeMemCopy(Mem*, const Mem*); 384 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 385 int sqlite3VdbeMemMove(Mem*, Mem*); 386 int sqlite3VdbeMemNulTerminate(Mem*); 387 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 388 void sqlite3VdbeMemSetInt64(Mem*, i64); 389 void sqlite3VdbeMemSetDouble(Mem*, double); 390 void sqlite3VdbeMemSetNull(Mem*); 391 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 392 int sqlite3VdbeMemMakeWriteable(Mem*); 393 int sqlite3VdbeMemDynamicify(Mem*); 394 int sqlite3VdbeMemStringify(Mem*, int); 395 i64 sqlite3VdbeIntValue(Mem*); 396 int sqlite3VdbeMemIntegerify(Mem*); 397 double sqlite3VdbeRealValue(Mem*); 398 void sqlite3VdbeIntegerAffinity(Mem*); 399 int sqlite3VdbeMemRealify(Mem*); 400 int sqlite3VdbeMemNumerify(Mem*); 401 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 402 void sqlite3VdbeMemRelease(Mem *p); 403 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 404 const char *sqlite3OpcodeName(int); 405 406 #ifndef NDEBUG 407 void sqlite3VdbeMemSanity(Mem*); 408 int sqlite3VdbeOpcodeNoPush(u8); 409 #endif 410 int sqlite3VdbeMemTranslate(Mem*, u8); 411 #ifdef SQLITE_DEBUG 412 void sqlite3VdbePrintSql(Vdbe*); 413 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 414 #endif 415 int sqlite3VdbeMemHandleBom(Mem *pMem); 416 void sqlite3VdbeFifoInit(Fifo*); 417 int sqlite3VdbeFifoPush(Fifo*, i64); 418 int sqlite3VdbeFifoPop(Fifo*, i64*); 419 void sqlite3VdbeFifoClear(Fifo*); 420 421 #ifndef SQLITE_OMIT_INCRBLOB 422 int sqlite3VdbeMemExpandBlob(Mem *); 423 #else 424 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK 425 #endif 426 427 #endif /* !defined(_VDBEINT_H_) */ 428