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 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ 64 i64 nextRowid; /* Next rowid returned by OP_NewRowid */ 65 Bool zeroed; /* True if zeroed out and ready for reuse */ 66 Bool rowidIsValid; /* True if lastRowid is valid */ 67 Bool atFirst; /* True if pointing to first entry */ 68 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 69 Bool nullRow; /* True if pointing to a row with no data */ 70 Bool nextRowidValid; /* True if the nextRowid field is valid */ 71 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ 72 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 73 Bool isTable; /* True if a table requiring integer keys */ 74 Bool isIndex; /* True if an index containing keys only - no data */ 75 u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */ 76 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 77 Btree *pBt; /* Separate file holding temporary table */ 78 int nData; /* Number of bytes in pData */ 79 char *pData; /* Data for a NEW or OLD pseudo-table */ 80 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ 81 u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */ 82 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 83 int nField; /* Number of fields in the header */ 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 ** zRow might point to (ephemeral) data for the current row, or it might 88 ** be NULL. */ 89 Bool cacheValid; /* True if the cache is valid */ 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 ** Internally, the vdbe manipulates nearly all SQL values as Mem 106 ** structures. Each Mem struct may cache multiple representations (string, 107 ** integer etc.) of the same value. A value (and therefore Mem structure) 108 ** has the following properties: 109 ** 110 ** Each value has a manifest type. The manifest type of the value stored 111 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 112 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 113 ** SQLITE_BLOB. 114 */ 115 struct Mem { 116 i64 i; /* Integer value */ 117 int n; /* Number of characters in string value, including '\0' */ 118 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 119 u8 type; /* One of MEM_Null, MEM_Str, etc. */ 120 u8 enc; /* TEXT_Utf8, TEXT_Utf16le, or TEXT_Utf16be */ 121 double r; /* Real value */ 122 char *z; /* String or BLOB value */ 123 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 124 char zShort[NBFS]; /* Space for short strings */ 125 }; 126 typedef struct Mem Mem; 127 128 /* 129 ** A sorter builds a list of elements to be sorted. Each element of 130 ** the list is an instance of the following structure. 131 */ 132 typedef struct Sorter Sorter; 133 struct Sorter { 134 int nKey; /* Number of bytes in the key */ 135 char *zKey; /* The key by which we will sort */ 136 Mem data; 137 Sorter *pNext; /* Next in the list */ 138 }; 139 140 /* 141 ** Number of buckets used for merge-sort. 142 */ 143 #define NSORT 30 144 145 /* One or more of the following flags are set to indicate the validOK 146 ** representations of the value stored in the Mem struct. 147 ** 148 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 149 ** No other flags may be set in this case. 150 ** 151 ** If the MEM_Str flag is set then Mem.z points at a string representation. 152 ** Usually this is encoded in the same unicode encoding as the main 153 ** database (see below for exceptions). If the MEM_Term flag is also 154 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 155 ** flags may coexist with the MEM_Str flag. 156 ** 157 ** Multiple of these values can appear in Mem.flags. But only one 158 ** at a time can appear in Mem.type. 159 */ 160 #define MEM_Null 0x0001 /* Value is NULL */ 161 #define MEM_Str 0x0002 /* Value is a string */ 162 #define MEM_Int 0x0004 /* Value is an integer */ 163 #define MEM_Real 0x0008 /* Value is a real number */ 164 #define MEM_Blob 0x0010 /* Value is a BLOB */ 165 166 /* Whenever Mem contains a valid string or blob representation, one of 167 ** the following flags must be set to determine the memory management 168 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 169 ** string is \000 or \u0000 terminated 170 */ 171 #define MEM_Term 0x0020 /* String rep is nul terminated */ 172 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ 173 #define MEM_Static 0x0080 /* Mem.z points to a static string */ 174 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ 175 #define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */ 176 177 /* The following MEM_ value appears only in AggElem.aMem.s.flag fields. 178 ** It indicates that the corresponding AggElem.aMem.z points to a 179 ** aggregate function context that needs to be finalized. 180 */ 181 #define MEM_AggCtx 0x0400 /* Mem.z points to an agg function context */ 182 183 184 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 185 ** additional information about auxiliary information bound to arguments 186 ** of the function. This is used to implement the sqlite3_get_auxdata() 187 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 188 ** that can be associated with a constant argument to a function. This 189 ** allows functions such as "regexp" to compile their constant regular 190 ** expression argument once and reused the compiled code for multiple 191 ** invocations. 192 */ 193 struct VdbeFunc { 194 FuncDef *pFunc; /* The definition of the function */ 195 int nAux; /* Number of entries allocated for apAux[] */ 196 struct AuxData { 197 void *pAux; /* Aux data for the i-th argument */ 198 void (*xDelete)(void *); /* Destructor for the aux data */ 199 } apAux[1]; /* One slot for each function argument */ 200 }; 201 typedef struct VdbeFunc VdbeFunc; 202 203 /* 204 ** The "context" argument for a installable function. A pointer to an 205 ** instance of this structure is the first argument to the routines used 206 ** implement the SQL functions. 207 ** 208 ** There is a typedef for this structure in sqlite.h. So all routines, 209 ** even the public interface to SQLite, can use a pointer to this structure. 210 ** But this file is the only place where the internal details of this 211 ** structure are known. 212 ** 213 ** This structure is defined inside of vdbe.c because it uses substructures 214 ** (Mem) which are only defined there. 215 */ 216 struct sqlite3_context { 217 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 218 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 219 Mem s; /* The return value is stored here */ 220 void *pAgg; /* Aggregate context */ 221 u8 isError; /* Set to true for an error */ 222 int cnt; /* Number of times that the step function has been called */ 223 CollSeq *pColl; 224 }; 225 226 /* 227 ** An Agg structure describes an Aggregator. Each Agg consists of 228 ** zero or more Aggregator elements (AggElem). Each AggElem contains 229 ** a key and one or more values. The values are used in processing 230 ** aggregate functions in a SELECT. The key is used to implement 231 ** the GROUP BY clause of a select. 232 */ 233 typedef struct Agg Agg; 234 typedef struct AggElem AggElem; 235 struct Agg { 236 int nMem; /* Number of values stored in each AggElem */ 237 AggElem *pCurrent; /* The AggElem currently in focus */ 238 FuncDef **apFunc; /* Information about aggregate functions */ 239 Btree *pBtree; /* The tmp. btree used to group elements, if required. */ 240 BtCursor *pCsr; /* Read/write cursor to the table in pBtree */ 241 int nTab; /* Root page of the table in pBtree */ 242 u8 searching; /* True between the first AggNext and AggReset */ 243 }; 244 struct AggElem { 245 char *zKey; /* The key to this AggElem */ 246 int nKey; /* Number of bytes in the key, including '\0' at end */ 247 Mem aMem[1]; /* The values for this AggElem */ 248 }; 249 250 /* 251 ** A Set structure is used for quick testing to see if a value 252 ** is part of a small set. Sets are used to implement code like 253 ** this: 254 ** x.y IN ('hi','hoo','hum') 255 */ 256 typedef struct Set Set; 257 struct Set { 258 Hash hash; /* A set is just a hash table */ 259 HashElem *prev; /* Previously accessed hash elemen */ 260 }; 261 262 /* 263 ** A FifoPage structure holds a single page of valves. Pages are arranged 264 ** in a list. 265 */ 266 typedef struct FifoPage FifoPage; 267 struct FifoPage { 268 u16 nSlot; /* Number of entries aSlot[] */ 269 u16 iWrite; /* Push the next value into this entry in aSlot[] */ 270 i16 iRead; /* Read the next value from this entry in aSlot[] */ 271 FifoPage *pNext; /* Next page in the fifo */ 272 i64 aSlot[1]; /* One or more slots for rowid values */ 273 }; 274 275 /* 276 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation 277 ** of that structure is private to this file. 278 ** 279 ** The Fifo structure describes the entire fifo. 280 */ 281 typedef struct Fifo Fifo; 282 struct Fifo { 283 int nEntry; /* Total number of entries */ 284 FifoPage *pFirst; /* First page on the list */ 285 FifoPage *pLast; /* Last page on the list */ 286 }; 287 288 /* 289 ** A Context stores the last insert rowid, the last statement change count, 290 ** and the current statement change count (i.e. changes since last statement). 291 ** The current keylist is also stored in the context. 292 ** Elements of Context structure type make up the ContextStack, which is 293 ** updated by the ContextPush and ContextPop opcodes (used by triggers). 294 ** The context is pushed before executing a trigger a popped when the 295 ** trigger finishes. 296 */ 297 typedef struct Context Context; 298 struct Context { 299 int lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 300 int nChange; /* Statement changes (Vdbe.nChanges) */ 301 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */ 302 }; 303 304 /* 305 ** An instance of the virtual machine. This structure contains the complete 306 ** state of the virtual machine. 307 ** 308 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 309 ** is really a pointer to an instance of this structure. 310 */ 311 struct Vdbe { 312 sqlite3 *db; /* The whole database */ 313 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 314 FILE *trace; /* Write an execution trace here, if not NULL */ 315 int nOp; /* Number of instructions in the program */ 316 int nOpAlloc; /* Number of slots allocated for aOp[] */ 317 Op *aOp; /* Space to hold the virtual machine's program */ 318 int nLabel; /* Number of labels used */ 319 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 320 int *aLabel; /* Space to hold the labels */ 321 Mem *aStack; /* The operand stack, except string values */ 322 Mem *pTos; /* Top entry in the operand stack */ 323 Mem **apArg; /* Arguments to currently executing user function */ 324 Mem *aColName; /* Column names to return */ 325 int nCursor; /* Number of slots in apCsr[] */ 326 Cursor **apCsr; /* One element of this array for each open cursor */ 327 Sorter *pSort; /* A linked list of objects to be sorted */ 328 Sorter *pSortTail; /* Last element on the pSort list */ 329 int nVar; /* Number of entries in aVar[] */ 330 Mem *aVar; /* Values for the OP_Variable opcode. */ 331 char **azVar; /* Name of variables */ 332 int okVar; /* True if azVar[] has been initialized */ 333 int magic; /* Magic number for sanity checking */ 334 int nMem; /* Number of memory locations currently allocated */ 335 Mem *aMem; /* The memory locations */ 336 int nAgg; /* Number of elements in apAgg */ 337 Agg *apAgg; /* Array of aggregate contexts */ 338 Agg *pAgg; /* Current aggregate context */ 339 int nCallback; /* Number of callbacks invoked so far */ 340 Fifo sFifo; /* A list of ROWIDs */ 341 int contextStackTop; /* Index of top element in the context stack */ 342 int contextStackDepth; /* The size of the "context" stack */ 343 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 344 int pc; /* The program counter */ 345 int rc; /* Value to return */ 346 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */ 347 int errorAction; /* Recovery action to do in case of an error */ 348 int inTempTrans; /* True if temp database is transactioned */ 349 int returnStack[100]; /* Return address stack for OP_Gosub & OP_Return */ 350 int returnDepth; /* Next unused element in returnStack[] */ 351 int nResColumn; /* Number of columns in one row of the result set */ 352 char **azResColumn; /* Values for one row of result */ 353 int popStack; /* Pop the stack this much on entry to VdbeExec() */ 354 char *zErrMsg; /* Error message written here */ 355 u8 resOnStack; /* True if there are result values on the stack */ 356 u8 explain; /* True if EXPLAIN present on SQL command */ 357 u8 changeCntOn; /* True to update the change-counter */ 358 u8 aborted; /* True if ROLLBACK in another VM causes an abort */ 359 u8 expired; /* True if the VM needs to be recompiled */ 360 int nChange; /* Number of db changes made since last reset */ 361 }; 362 363 /* 364 ** The following are allowed values for Vdbe.magic 365 */ 366 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 367 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 368 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 369 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 370 371 /* 372 ** Function prototypes 373 */ 374 void sqlite3VdbeFreeCursor(Cursor*); 375 void sqlite3VdbeSorterReset(Vdbe*); 376 int sqlite3VdbeAggReset(sqlite3*, Agg *, KeyInfo *); 377 void sqliteVdbePopStack(Vdbe*,int); 378 int sqlite3VdbeCursorMoveto(Cursor*); 379 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 380 void sqlite3VdbePrintOp(FILE*, int, Op*); 381 #endif 382 #ifdef SQLITE_DEBUG 383 void sqlite3VdbePrintSql(Vdbe*); 384 #endif 385 int sqlite3VdbeSerialTypeLen(u32); 386 u32 sqlite3VdbeSerialType(Mem*); 387 int sqlite3VdbeSerialPut(unsigned char*, Mem*); 388 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 389 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 390 391 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 392 int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*); 393 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 394 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 395 int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*); 396 int sqlite3VdbeIdxRowidLen(int,const u8*); 397 int sqlite3VdbeExec(Vdbe*); 398 int sqlite3VdbeList(Vdbe*); 399 int sqlite3VdbeHalt(Vdbe*); 400 int sqlite3VdbeChangeEncoding(Mem *, int); 401 int sqlite3VdbeMemCopy(Mem*, const Mem*); 402 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 403 int sqlite3VdbeMemMove(Mem*, Mem*); 404 int sqlite3VdbeMemNulTerminate(Mem*); 405 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 406 void sqlite3VdbeMemSetInt64(Mem*, i64); 407 void sqlite3VdbeMemSetDouble(Mem*, double); 408 void sqlite3VdbeMemSetNull(Mem*); 409 int sqlite3VdbeMemMakeWriteable(Mem*); 410 int sqlite3VdbeMemDynamicify(Mem*); 411 int sqlite3VdbeMemStringify(Mem*, int); 412 i64 sqlite3VdbeIntValue(Mem*); 413 int sqlite3VdbeMemIntegerify(Mem*); 414 double sqlite3VdbeRealValue(Mem*); 415 int sqlite3VdbeMemRealify(Mem*); 416 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 417 void sqlite3VdbeMemRelease(Mem *p); 418 #ifndef NDEBUG 419 void sqlite3VdbeMemSanity(Mem*, u8); 420 int sqlite3VdbeOpcodeNoPush(u8); 421 #endif 422 int sqlite3VdbeMemTranslate(Mem*, u8); 423 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf, int nBuf); 424 int sqlite3VdbeMemHandleBom(Mem *pMem); 425 void sqlite3VdbeFifoInit(Fifo*); 426 int sqlite3VdbeFifoPush(Fifo*, i64); 427 int sqlite3VdbeFifoPop(Fifo*, i64*); 428 void sqlite3VdbeFifoClear(Fifo*); 429