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 ** The makefile scans the vdbe.c source file and creates the following 30 ** array of string constants which are the names of all VDBE opcodes. This 31 ** array is defined in a separate source code file named opcode.c which is 32 ** automatically generated by the makefile. 33 */ 34 extern const char *const sqlite3OpcodeNames[]; 35 36 /* 37 ** SQL is translated into a sequence of instructions to be 38 ** executed by a virtual machine. Each instruction is an instance 39 ** of the following structure. 40 */ 41 typedef struct VdbeOp Op; 42 43 /* 44 ** Boolean values 45 */ 46 typedef unsigned char Bool; 47 48 /* 49 ** A cursor is a pointer into a single BTree within a database file. 50 ** The cursor can seek to a BTree entry with a particular key, or 51 ** loop over all entries of the Btree. You can also insert new BTree 52 ** entries or retrieve the key or data from the entry that the cursor 53 ** is currently pointing to. 54 ** 55 ** Every cursor that the virtual machine has open is represented by an 56 ** instance of the following structure. 57 ** 58 ** If the Cursor.isTriggerRow flag is set it means that this cursor is 59 ** really a single row that represents the NEW or OLD pseudo-table of 60 ** a row trigger. The data for the row is stored in Cursor.pData and 61 ** the rowid is in Cursor.iKey. 62 */ 63 struct Cursor { 64 BtCursor *pCursor; /* The cursor structure of the backend */ 65 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ 66 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ 67 i64 nextRowid; /* Next rowid returned by OP_NewRowid */ 68 Bool zeroed; /* True if zeroed out and ready for reuse */ 69 Bool rowidIsValid; /* True if lastRowid is valid */ 70 Bool atFirst; /* True if pointing to first entry */ 71 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ 72 Bool nullRow; /* True if pointing to a row with no data */ 73 Bool nextRowidValid; /* True if the nextRowid field is valid */ 74 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ 75 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ 76 Bool isTable; /* True if a table requiring integer keys */ 77 Bool isIndex; /* True if an index containing keys only - no data */ 78 u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */ 79 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ 80 Btree *pBt; /* Separate file holding temporary table */ 81 int nData; /* Number of bytes in pData */ 82 char *pData; /* Data for a NEW or OLD pseudo-table */ 83 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ 84 u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */ 85 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ 86 int nField; /* Number of fields in the header */ 87 i64 seqCount; /* Sequence counter */ 88 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ 89 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ 90 91 /* Cached information about the header for the data record that the 92 ** cursor is currently pointing to. Only valid if cacheValid is true. 93 ** aRow might point to (ephemeral) data for the current row, or it might 94 ** be NULL. 95 */ 96 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ 97 int payloadSize; /* Total number of bytes in the record */ 98 u32 *aType; /* Type values for all entries in the record */ 99 u32 *aOffset; /* Cached offsets to the start of each columns data */ 100 u8 *aRow; /* Data for the current row, if all on one page */ 101 }; 102 typedef struct Cursor Cursor; 103 104 /* 105 ** Number of bytes of string storage space available to each stack 106 ** layer without having to malloc. NBFS is short for Number of Bytes 107 ** For Strings. 108 */ 109 #define NBFS 32 110 111 /* 112 ** A value for Cursor.cacheValid that means the cache is always invalid. 113 */ 114 #define CACHE_STALE 0 115 116 /* 117 ** Internally, the vdbe manipulates nearly all SQL values as Mem 118 ** structures. Each Mem struct may cache multiple representations (string, 119 ** integer etc.) of the same value. A value (and therefore Mem structure) 120 ** has the following properties: 121 ** 122 ** Each value has a manifest type. The manifest type of the value stored 123 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 124 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 125 ** SQLITE_BLOB. 126 */ 127 struct Mem { 128 union { 129 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */ 130 FuncDef *pDef; /* Used only when flags==MEM_Agg */ 131 } u; 132 double r; /* Real value */ 133 char *z; /* String or BLOB value */ 134 int n; /* Number of characters in string value, including '\0' */ 135 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 136 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */ 137 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */ 138 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 139 char zShort[NBFS]; /* Space for short strings */ 140 }; 141 typedef struct Mem Mem; 142 143 /* One or more of the following flags are set to indicate the validOK 144 ** representations of the value stored in the Mem struct. 145 ** 146 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 147 ** No other flags may be set in this case. 148 ** 149 ** If the MEM_Str flag is set then Mem.z points at a string representation. 150 ** Usually this is encoded in the same unicode encoding as the main 151 ** database (see below for exceptions). If the MEM_Term flag is also 152 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 153 ** flags may coexist with the MEM_Str flag. 154 ** 155 ** Multiple of these values can appear in Mem.flags. But only one 156 ** at a time can appear in Mem.type. 157 */ 158 #define MEM_Null 0x0001 /* Value is NULL */ 159 #define MEM_Str 0x0002 /* Value is a string */ 160 #define MEM_Int 0x0004 /* Value is an integer */ 161 #define MEM_Real 0x0008 /* Value is a real number */ 162 #define MEM_Blob 0x0010 /* Value is a BLOB */ 163 164 /* Whenever Mem contains a valid string or blob representation, one of 165 ** the following flags must be set to determine the memory management 166 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 167 ** string is \000 or \u0000 terminated 168 */ 169 #define MEM_Term 0x0020 /* String rep is nul terminated */ 170 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ 171 #define MEM_Static 0x0080 /* Mem.z points to a static string */ 172 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ 173 #define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */ 174 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */ 175 #define MEM_Zero 0x0800 /* Mem.i contains count of 0s appended to blob */ 176 177 178 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 179 ** additional information about auxiliary information bound to arguments 180 ** of the function. This is used to implement the sqlite3_get_auxdata() 181 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 182 ** that can be associated with a constant argument to a function. This 183 ** allows functions such as "regexp" to compile their constant regular 184 ** expression argument once and reused the compiled code for multiple 185 ** invocations. 186 */ 187 struct VdbeFunc { 188 FuncDef *pFunc; /* The definition of the function */ 189 int nAux; /* Number of entries allocated for apAux[] */ 190 struct AuxData { 191 void *pAux; /* Aux data for the i-th argument */ 192 void (*xDelete)(void *); /* Destructor for the aux data */ 193 } apAux[1]; /* One slot for each function argument */ 194 }; 195 typedef struct VdbeFunc VdbeFunc; 196 197 /* 198 ** The "context" argument for a installable function. A pointer to an 199 ** instance of this structure is the first argument to the routines used 200 ** implement the SQL functions. 201 ** 202 ** There is a typedef for this structure in sqlite.h. So all routines, 203 ** even the public interface to SQLite, can use a pointer to this structure. 204 ** But this file is the only place where the internal details of this 205 ** structure are known. 206 ** 207 ** This structure is defined inside of vdbeInt.h because it uses substructures 208 ** (Mem) which are only defined there. 209 */ 210 struct sqlite3_context { 211 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 212 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 213 Mem s; /* The return value is stored here */ 214 Mem *pMem; /* Memory cell used to store aggregate context */ 215 u8 isError; /* Set to true for an error */ 216 CollSeq *pColl; /* Collating sequence */ 217 }; 218 219 /* 220 ** A Set structure is used for quick testing to see if a value 221 ** is part of a small set. Sets are used to implement code like 222 ** this: 223 ** x.y IN ('hi','hoo','hum') 224 */ 225 typedef struct Set Set; 226 struct Set { 227 Hash hash; /* A set is just a hash table */ 228 HashElem *prev; /* Previously accessed hash elemen */ 229 }; 230 231 /* 232 ** A FifoPage structure holds a single page of valves. Pages are arranged 233 ** in a list. 234 */ 235 typedef struct FifoPage FifoPage; 236 struct FifoPage { 237 int nSlot; /* Number of entries aSlot[] */ 238 int iWrite; /* Push the next value into this entry in aSlot[] */ 239 int iRead; /* Read the next value from this entry in aSlot[] */ 240 FifoPage *pNext; /* Next page in the fifo */ 241 i64 aSlot[1]; /* One or more slots for rowid values */ 242 }; 243 244 /* 245 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation 246 ** of that structure is private to this file. 247 ** 248 ** The Fifo structure describes the entire fifo. 249 */ 250 typedef struct Fifo Fifo; 251 struct Fifo { 252 int nEntry; /* Total number of entries */ 253 FifoPage *pFirst; /* First page on the list */ 254 FifoPage *pLast; /* Last page on the list */ 255 }; 256 257 /* 258 ** A Context stores the last insert rowid, the last statement change count, 259 ** and the current statement change count (i.e. changes since last statement). 260 ** The current keylist is also stored in the context. 261 ** Elements of Context structure type make up the ContextStack, which is 262 ** updated by the ContextPush and ContextPop opcodes (used by triggers). 263 ** The context is pushed before executing a trigger a popped when the 264 ** trigger finishes. 265 */ 266 typedef struct Context Context; 267 struct Context { 268 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 269 int nChange; /* Statement changes (Vdbe.nChanges) */ 270 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */ 271 }; 272 273 /* 274 ** An instance of the virtual machine. This structure contains the complete 275 ** state of the virtual machine. 276 ** 277 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 278 ** is really a pointer to an instance of this structure. 279 ** 280 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of 281 ** any virtual table method invocations made by the vdbe program. It is 282 ** set to 2 for xDestroy method calls and 1 for all other methods. This 283 ** variable is used for two purposes: to allow xDestroy methods to execute 284 ** "DROP TABLE" statements and to prevent some nasty side effects of 285 ** malloc failure when SQLite is invoked recursively by a virtual table 286 ** method function. 287 */ 288 struct Vdbe { 289 sqlite3 *db; /* The whole database */ 290 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 291 FILE *trace; /* Write an execution trace here, if not NULL */ 292 int nOp; /* Number of instructions in the program */ 293 int nOpAlloc; /* Number of slots allocated for aOp[] */ 294 Op *aOp; /* Space to hold the virtual machine's program */ 295 int nLabel; /* Number of labels used */ 296 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 297 int *aLabel; /* Space to hold the labels */ 298 Mem *aStack; /* The operand stack, except string values */ 299 Mem *pTos; /* Top entry in the operand stack */ 300 Mem **apArg; /* Arguments to currently executing user function */ 301 Mem *aColName; /* Column names to return */ 302 int nCursor; /* Number of slots in apCsr[] */ 303 Cursor **apCsr; /* One element of this array for each open cursor */ 304 int nVar; /* Number of entries in aVar[] */ 305 Mem *aVar; /* Values for the OP_Variable opcode. */ 306 char **azVar; /* Name of variables */ 307 int okVar; /* True if azVar[] has been initialized */ 308 int magic; /* Magic number for sanity checking */ 309 int nMem; /* Number of memory locations currently allocated */ 310 Mem *aMem; /* The memory locations */ 311 int nCallback; /* Number of callbacks invoked so far */ 312 int cacheCtr; /* Cursor row cache generation counter */ 313 Fifo sFifo; /* A list of ROWIDs */ 314 int contextStackTop; /* Index of top element in the context stack */ 315 int contextStackDepth; /* The size of the "context" stack */ 316 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 317 int pc; /* The program counter */ 318 int rc; /* Value to return */ 319 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */ 320 int errorAction; /* Recovery action to do in case of an error */ 321 int inTempTrans; /* True if temp database is transactioned */ 322 int returnStack[100]; /* Return address stack for OP_Gosub & OP_Return */ 323 int returnDepth; /* Next unused element in returnStack[] */ 324 int nResColumn; /* Number of columns in one row of the result set */ 325 char **azResColumn; /* Values for one row of result */ 326 int popStack; /* Pop the stack this much on entry to VdbeExec() */ 327 char *zErrMsg; /* Error message written here */ 328 u8 resOnStack; /* True if there are result values on the stack */ 329 u8 explain; /* True if EXPLAIN present on SQL command */ 330 u8 changeCntOn; /* True to update the change-counter */ 331 u8 aborted; /* True if ROLLBACK in another VM causes an abort */ 332 u8 expired; /* True if the VM needs to be recompiled */ 333 u8 minWriteFileFormat; /* Minimum file format for writable database files */ 334 u8 inVtabMethod; /* See comments above */ 335 int nChange; /* Number of db changes made since last reset */ 336 i64 startTime; /* Time when query started - used for profiling */ 337 int nSql; /* Number of bytes in zSql */ 338 char *zSql; /* Text of the SQL statement that generated this */ 339 #ifdef SQLITE_SSE 340 int fetchId; /* Statement number used by sqlite3_fetch_statement */ 341 int lru; /* Counter used for LRU cache replacement */ 342 #endif 343 }; 344 345 /* 346 ** The following are allowed values for Vdbe.magic 347 */ 348 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 349 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 350 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 351 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 352 353 /* 354 ** Function prototypes 355 */ 356 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*); 357 void sqliteVdbePopStack(Vdbe*,int); 358 int sqlite3VdbeCursorMoveto(Cursor*); 359 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 360 void sqlite3VdbePrintOp(FILE*, int, Op*); 361 #endif 362 #ifdef SQLITE_DEBUG 363 void sqlite3VdbePrintSql(Vdbe*); 364 #endif 365 int sqlite3VdbeSerialTypeLen(u32); 366 u32 sqlite3VdbeSerialType(Mem*, int); 367 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int); 368 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 369 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 370 371 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 372 int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*); 373 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 374 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 375 int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*); 376 int sqlite3VdbeIdxRowidLen(const u8*); 377 int sqlite3VdbeExec(Vdbe*); 378 int sqlite3VdbeList(Vdbe*); 379 int sqlite3VdbeHalt(Vdbe*); 380 int sqlite3VdbeChangeEncoding(Mem *, int); 381 int sqlite3VdbeMemCopy(Mem*, const Mem*); 382 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 383 int sqlite3VdbeMemMove(Mem*, Mem*); 384 int sqlite3VdbeMemNulTerminate(Mem*); 385 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 386 void sqlite3VdbeMemSetInt64(Mem*, i64); 387 void sqlite3VdbeMemSetDouble(Mem*, double); 388 void sqlite3VdbeMemSetNull(Mem*); 389 void sqlite3VdbeMemSetZeroBlob(Mem*,int); 390 int sqlite3VdbeMemExpandBlob(Mem*); 391 int sqlite3VdbeMemMakeWriteable(Mem*); 392 int sqlite3VdbeMemDynamicify(Mem*); 393 int sqlite3VdbeMemStringify(Mem*, int); 394 i64 sqlite3VdbeIntValue(Mem*); 395 int sqlite3VdbeMemIntegerify(Mem*); 396 double sqlite3VdbeRealValue(Mem*); 397 void sqlite3VdbeIntegerAffinity(Mem*); 398 int sqlite3VdbeMemRealify(Mem*); 399 int sqlite3VdbeMemNumerify(Mem*); 400 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 401 void sqlite3VdbeMemRelease(Mem *p); 402 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); 403 #ifndef NDEBUG 404 void sqlite3VdbeMemSanity(Mem*); 405 int sqlite3VdbeOpcodeNoPush(u8); 406 #endif 407 int sqlite3VdbeMemTranslate(Mem*, u8); 408 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); 409 int sqlite3VdbeMemHandleBom(Mem *pMem); 410 void sqlite3VdbeFifoInit(Fifo*); 411 int sqlite3VdbeFifoPush(Fifo*, i64); 412 int sqlite3VdbeFifoPop(Fifo*, i64*); 413 void sqlite3VdbeFifoClear(Fifo*); 414 415 #endif /* !defined(_VDBEINT_H_) */ 416