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 19 /* 20 ** intToKey() and keyToInt() used to transform the rowid. But with 21 ** the latest versions of the design they are no-ops. 22 */ 23 #define keyToInt(X) (X) 24 #define intToKey(X) (X) 25 26 /* 27 ** The makefile scans the vdbe.c source file and creates the following 28 ** array of string constants which are the names of all VDBE opcodes. This 29 ** array is defined in a separate source code file named opcode.c which is 30 ** automatically generated by the makefile. 31 */ 32 extern char *sqlite3OpcodeNames[]; 33 34 /* 35 ** SQL is translated into a sequence of instructions to be 36 ** executed by a virtual machine. Each instruction is an instance 37 ** of the following structure. 38 */ 39 typedef struct VdbeOp Op; 40 41 /* 42 ** Boolean values 43 */ 44 typedef unsigned char Bool; 45 46 /* 47 ** A cursor is a pointer into a single BTree within a database file. 48 ** The cursor can seek to a BTree entry with a particular key, or 49 ** loop over all entries of the Btree. You can also insert new BTree 50 ** entries or retrieve the key or data from the entry that the cursor 51 ** is currently pointing to. 52 ** 53 ** Every cursor that the virtual machine has open is represented by an 54 ** instance of the following structure. 55 ** 56 ** If the Cursor.isTriggerRow flag is set it means that this cursor is 57 ** really a single row that represents the NEW or OLD pseudo-table of 58 ** a row trigger. The data for the row is stored in Cursor.pData and 59 ** the rowid is in Cursor.iKey. 60 */ 61 struct Cursor { 62 BtCursor *pCursor; /* The cursor structure of the backend */ 63 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ 64 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ 65 i64 nextRowid; /* Next rowid returned by OP_NewRowid */ 66 Bool zeroed; /* True if zeroed out and ready for reuse */ 67 Bool rowidIsValid; /* True if lastRowid is valid */ 68 Bool atFirst; /* True if pointing to first entry */ 69 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 70 Bool nullRow; /* True if pointing to a row with no data */ 71 Bool nextRowidValid; /* True if the nextRowid field is valid */ 72 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ 73 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 74 Bool isTable; /* True if a table requiring integer keys */ 75 Bool isIndex; /* True if an index containing keys only - no data */ 76 u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */ 77 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 78 Btree *pBt; /* Separate file holding temporary table */ 79 int nData; /* Number of bytes in pData */ 80 char *pData; /* Data for a NEW or OLD pseudo-table */ 81 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ 82 u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */ 83 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 84 int nField; /* Number of fields in the header */ 85 i64 seqCount; /* Sequence counter */ 86 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 87 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 88 89 /* Cached information about the header for the data record that the 90 ** cursor is currently pointing to. Only valid if cacheValid is true. 91 ** aRow might point to (ephemeral) data for the current row, or it might 92 ** be NULL. 93 */ 94 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 95 int payloadSize; /* Total number of bytes in the record */ 96 u32 *aType; /* Type values for all entries in the record */ 97 u32 *aOffset; /* Cached offsets to the start of each columns data */ 98 u8 *aRow; /* Data for the current row, if all on one page */ 99 }; 100 typedef struct Cursor Cursor; 101 102 /* 103 ** Number of bytes of string storage space available to each stack 104 ** layer without having to malloc. NBFS is short for Number of Bytes 105 ** For Strings. 106 */ 107 #define NBFS 32 108 109 /* 110 ** A value for Cursor.cacheValid that means the cache is always invalid. 111 */ 112 #define CACHE_STALE 0 113 114 /* 115 ** Internally, the vdbe manipulates nearly all SQL values as Mem 116 ** structures. Each Mem struct may cache multiple representations (string, 117 ** integer etc.) of the same value. A value (and therefore Mem structure) 118 ** has the following properties: 119 ** 120 ** Each value has a manifest type. The manifest type of the value stored 121 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 122 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 123 ** SQLITE_BLOB. 124 */ 125 struct Mem { 126 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */ 127 double r; /* Real value */ 128 char *z; /* String or BLOB value */ 129 int n; /* Number of characters in string value, including '\0' */ 130 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 131 u8 type; /* One of MEM_Null, MEM_Str, etc. */ 132 u8 enc; /* TEXT_Utf8, TEXT_Utf16le, or TEXT_Utf16be */ 133 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 134 char zShort[NBFS]; /* Space for short strings */ 135 }; 136 typedef struct Mem Mem; 137 138 /* One or more of the following flags are set to indicate the validOK 139 ** representations of the value stored in the Mem struct. 140 ** 141 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 142 ** No other flags may be set in this case. 143 ** 144 ** If the MEM_Str flag is set then Mem.z points at a string representation. 145 ** Usually this is encoded in the same unicode encoding as the main 146 ** database (see below for exceptions). If the MEM_Term flag is also 147 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 148 ** flags may coexist with the MEM_Str flag. 149 ** 150 ** Multiple of these values can appear in Mem.flags. But only one 151 ** at a time can appear in Mem.type. 152 */ 153 #define MEM_Null 0x0001 /* Value is NULL */ 154 #define MEM_Str 0x0002 /* Value is a string */ 155 #define MEM_Int 0x0004 /* Value is an integer */ 156 #define MEM_Real 0x0008 /* Value is a real number */ 157 #define MEM_Blob 0x0010 /* Value is a BLOB */ 158 159 /* Whenever Mem contains a valid string or blob representation, one of 160 ** the following flags must be set to determine the memory management 161 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 162 ** string is \000 or \u0000 terminated 163 */ 164 #define MEM_Term 0x0020 /* String rep is nul terminated */ 165 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ 166 #define MEM_Static 0x0080 /* Mem.z points to a static string */ 167 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ 168 #define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */ 169 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */ 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 typedef struct VdbeFunc VdbeFunc; 190 191 /* 192 ** The "context" argument for a installable function. A pointer to an 193 ** instance of this structure is the first argument to the routines used 194 ** implement the SQL functions. 195 ** 196 ** There is a typedef for this structure in sqlite.h. So all routines, 197 ** even the public interface to SQLite, can use a pointer to this structure. 198 ** But this file is the only place where the internal details of this 199 ** structure are known. 200 ** 201 ** This structure is defined inside of vdbeInt.h because it uses substructures 202 ** (Mem) which are only defined there. 203 */ 204 struct sqlite3_context { 205 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 206 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 207 Mem s; /* The return value is stored here */ 208 Mem *pMem; /* Memory cell used to store aggregate context */ 209 u8 isError; /* Set to true for an error */ 210 CollSeq *pColl; /* Collating sequence */ 211 }; 212 213 /* 214 ** A Set structure is used for quick testing to see if a value 215 ** is part of a small set. Sets are used to implement code like 216 ** this: 217 ** x.y IN ('hi','hoo','hum') 218 */ 219 typedef struct Set Set; 220 struct Set { 221 Hash hash; /* A set is just a hash table */ 222 HashElem *prev; /* Previously accessed hash elemen */ 223 }; 224 225 /* 226 ** A FifoPage structure holds a single page of valves. Pages are arranged 227 ** in a list. 228 */ 229 typedef struct FifoPage FifoPage; 230 struct FifoPage { 231 int nSlot; /* Number of entries aSlot[] */ 232 int iWrite; /* Push the next value into this entry in aSlot[] */ 233 int iRead; /* Read the next value from this entry in aSlot[] */ 234 FifoPage *pNext; /* Next page in the fifo */ 235 i64 aSlot[1]; /* One or more slots for rowid values */ 236 }; 237 238 /* 239 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation 240 ** of that structure is private to this file. 241 ** 242 ** The Fifo structure describes the entire fifo. 243 */ 244 typedef struct Fifo Fifo; 245 struct Fifo { 246 int nEntry; /* Total number of entries */ 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 FILE *trace; /* Write an execution trace here, if not NULL */ 286 int nOp; /* Number of instructions in the program */ 287 int nOpAlloc; /* Number of slots allocated for aOp[] */ 288 Op *aOp; /* Space to hold the virtual machine's program */ 289 int nLabel; /* Number of labels used */ 290 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 291 int *aLabel; /* Space to hold the labels */ 292 Mem *aStack; /* The operand stack, except string values */ 293 Mem *pTos; /* Top entry in the operand stack */ 294 Mem **apArg; /* Arguments to currently executing user function */ 295 Mem *aColName; /* Column names to return */ 296 int nCursor; /* Number of slots in apCsr[] */ 297 Cursor **apCsr; /* One element of this array for each open cursor */ 298 int nVar; /* Number of entries in aVar[] */ 299 Mem *aVar; /* Values for the OP_Variable opcode. */ 300 char **azVar; /* Name of variables */ 301 int okVar; /* True if azVar[] has been initialized */ 302 int magic; /* Magic number for sanity checking */ 303 int nMem; /* Number of memory locations currently allocated */ 304 Mem *aMem; /* The memory locations */ 305 int nCallback; /* Number of callbacks invoked so far */ 306 int cacheCtr; /* Cursor row cache generation counter */ 307 Fifo sFifo; /* A list of ROWIDs */ 308 int contextStackTop; /* Index of top element in the context stack */ 309 int contextStackDepth; /* The size of the "context" stack */ 310 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 311 int pc; /* The program counter */ 312 int rc; /* Value to return */ 313 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */ 314 int errorAction; /* Recovery action to do in case of an error */ 315 int inTempTrans; /* True if temp database is transactioned */ 316 int returnStack[100]; /* Return address stack for OP_Gosub & OP_Return */ 317 int returnDepth; /* Next unused element in returnStack[] */ 318 int nResColumn; /* Number of columns in one row of the result set */ 319 char **azResColumn; /* Values for one row of result */ 320 int popStack; /* Pop the stack this much on entry to VdbeExec() */ 321 char *zErrMsg; /* Error message written here */ 322 u8 resOnStack; /* True if there are result values on the stack */ 323 u8 explain; /* True if EXPLAIN present on SQL command */ 324 u8 changeCntOn; /* True to update the change-counter */ 325 u8 aborted; /* True if ROLLBACK in another VM causes an abort */ 326 u8 expired; /* True if the VM needs to be recompiled */ 327 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 328 u8 inVtabMethod; /* See comments above */ 329 int nChange; /* Number of db changes made since last reset */ 330 i64 startTime; /* Time when query started - used for profiling */ 331 int nSql; /* Number of bytes in zSql */ 332 char *zSql; /* Text of the SQL statement that generated this */ 333 #ifdef SQLITE_SSE 334 int fetchId; /* Statement number used by sqlite3_fetch_statement */ 335 int lru; /* Counter used for LRU cache replacement */ 336 #endif 337 }; 338 339 /* 340 ** The following are allowed values for Vdbe.magic 341 */ 342 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 343 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 344 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 345 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 346 347 /* 348 ** Function prototypes 349 */ 350 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*); 351 void sqliteVdbePopStack(Vdbe*,int); 352 int sqlite3VdbeCursorMoveto(Cursor*); 353 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 354 void sqlite3VdbePrintOp(FILE*, int, Op*); 355 #endif 356 #ifdef SQLITE_DEBUG 357 void sqlite3VdbePrintSql(Vdbe*); 358 #endif 359 int sqlite3VdbeSerialTypeLen(u32); 360 u32 sqlite3VdbeSerialType(Mem*, int); 361 int sqlite3VdbeSerialPut(unsigned char*, 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*, int , const unsigned char*, int*); 367 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 368 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 369 int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*); 370 int sqlite3VdbeIdxRowidLen(const u8*); 371 int sqlite3VdbeExec(Vdbe*); 372 int sqlite3VdbeList(Vdbe*); 373 int sqlite3VdbeHalt(Vdbe*); 374 int sqlite3VdbeChangeEncoding(Mem *, int); 375 int sqlite3VdbeMemCopy(Mem*, const Mem*); 376 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 377 int sqlite3VdbeMemMove(Mem*, Mem*); 378 int sqlite3VdbeMemNulTerminate(Mem*); 379 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 380 void sqlite3VdbeMemSetInt64(Mem*, i64); 381 void sqlite3VdbeMemSetDouble(Mem*, double); 382 void sqlite3VdbeMemSetNull(Mem*); 383 int sqlite3VdbeMemMakeWriteable(Mem*); 384 int sqlite3VdbeMemDynamicify(Mem*); 385 int sqlite3VdbeMemStringify(Mem*, int); 386 i64 sqlite3VdbeIntValue(Mem*); 387 int sqlite3VdbeMemIntegerify(Mem*); 388 double sqlite3VdbeRealValue(Mem*); 389 void sqlite3VdbeIntegerAffinity(Mem*); 390 int sqlite3VdbeMemRealify(Mem*); 391 int sqlite3VdbeMemNumerify(Mem*); 392 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 393 void sqlite3VdbeMemRelease(Mem *p); 394 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 395 #ifndef NDEBUG 396 void sqlite3VdbeMemSanity(Mem*); 397 int sqlite3VdbeOpcodeNoPush(u8); 398 #endif 399 int sqlite3VdbeMemTranslate(Mem*, u8); 400 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 401 int sqlite3VdbeMemHandleBom(Mem *pMem); 402 void sqlite3VdbeFifoInit(Fifo*); 403 int sqlite3VdbeFifoPush(Fifo*, i64); 404 int sqlite3VdbeFifoPop(Fifo*, i64*); 405 void sqlite3VdbeFifoClear(Fifo*); 406