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 i64 seqCount; /* Sequence counter */ 85 86 /* Cached information about the header for the data record that the 87 ** cursor is currently pointing to. Only valid if cacheValid is true. 88 ** zRow might point to (ephemeral) data for the current row, or it might 89 ** be NULL. */ 90 Bool cacheValid; /* True if the cache is valid */ 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 ** Number of bytes of string storage space available to each stack 100 ** layer without having to malloc. NBFS is short for Number of Bytes 101 ** For Strings. 102 */ 103 #define NBFS 32 104 105 /* 106 ** Internally, the vdbe manipulates nearly all SQL values as Mem 107 ** structures. Each Mem struct may cache multiple representations (string, 108 ** integer etc.) of the same value. A value (and therefore Mem structure) 109 ** has the following properties: 110 ** 111 ** Each value has a manifest type. The manifest type of the value stored 112 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 113 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 114 ** SQLITE_BLOB. 115 */ 116 struct Mem { 117 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */ 118 double r; /* Real value */ 119 char *z; /* String or BLOB value */ 120 int n; /* Number of characters in string value, including '\0' */ 121 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 122 u8 type; /* One of MEM_Null, MEM_Str, etc. */ 123 u8 enc; /* TEXT_Utf8, TEXT_Utf16le, or TEXT_Utf16be */ 124 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ 125 char zShort[NBFS]; /* Space for short strings */ 126 }; 127 typedef struct Mem Mem; 128 129 /* One or more of the following flags are set to indicate the validOK 130 ** representations of the value stored in the Mem struct. 131 ** 132 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 133 ** No other flags may be set in this case. 134 ** 135 ** If the MEM_Str flag is set then Mem.z points at a string representation. 136 ** Usually this is encoded in the same unicode encoding as the main 137 ** database (see below for exceptions). If the MEM_Term flag is also 138 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 139 ** flags may coexist with the MEM_Str flag. 140 ** 141 ** Multiple of these values can appear in Mem.flags. But only one 142 ** at a time can appear in Mem.type. 143 */ 144 #define MEM_Null 0x0001 /* Value is NULL */ 145 #define MEM_Str 0x0002 /* Value is a string */ 146 #define MEM_Int 0x0004 /* Value is an integer */ 147 #define MEM_Real 0x0008 /* Value is a real number */ 148 #define MEM_Blob 0x0010 /* Value is a BLOB */ 149 150 /* Whenever Mem contains a valid string or blob representation, one of 151 ** the following flags must be set to determine the memory management 152 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 153 ** string is \000 or \u0000 terminated 154 */ 155 #define MEM_Term 0x0020 /* String rep is nul terminated */ 156 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ 157 #define MEM_Static 0x0080 /* Mem.z points to a static string */ 158 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ 159 #define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */ 160 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */ 161 162 163 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains 164 ** additional information about auxiliary information bound to arguments 165 ** of the function. This is used to implement the sqlite3_get_auxdata() 166 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data 167 ** that can be associated with a constant argument to a function. This 168 ** allows functions such as "regexp" to compile their constant regular 169 ** expression argument once and reused the compiled code for multiple 170 ** invocations. 171 */ 172 struct VdbeFunc { 173 FuncDef *pFunc; /* The definition of the function */ 174 int nAux; /* Number of entries allocated for apAux[] */ 175 struct AuxData { 176 void *pAux; /* Aux data for the i-th argument */ 177 void (*xDelete)(void *); /* Destructor for the aux data */ 178 } apAux[1]; /* One slot for each function argument */ 179 }; 180 typedef struct VdbeFunc VdbeFunc; 181 182 /* 183 ** The "context" argument for a installable function. A pointer to an 184 ** instance of this structure is the first argument to the routines used 185 ** implement the SQL functions. 186 ** 187 ** There is a typedef for this structure in sqlite.h. So all routines, 188 ** even the public interface to SQLite, can use a pointer to this structure. 189 ** But this file is the only place where the internal details of this 190 ** structure are known. 191 ** 192 ** This structure is defined inside of vdbeInt.h because it uses substructures 193 ** (Mem) which are only defined there. 194 */ 195 struct sqlite3_context { 196 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 197 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 198 Mem s; /* The return value is stored here */ 199 Mem *pMem; /* Memory cell used to store aggregate context */ 200 u8 isError; /* Set to true for an error */ 201 CollSeq *pColl; /* Collating sequence */ 202 }; 203 204 /* 205 ** A Set structure is used for quick testing to see if a value 206 ** is part of a small set. Sets are used to implement code like 207 ** this: 208 ** x.y IN ('hi','hoo','hum') 209 */ 210 typedef struct Set Set; 211 struct Set { 212 Hash hash; /* A set is just a hash table */ 213 HashElem *prev; /* Previously accessed hash elemen */ 214 }; 215 216 /* 217 ** A FifoPage structure holds a single page of valves. Pages are arranged 218 ** in a list. 219 */ 220 typedef struct FifoPage FifoPage; 221 struct FifoPage { 222 int nSlot; /* Number of entries aSlot[] */ 223 int iWrite; /* Push the next value into this entry in aSlot[] */ 224 int iRead; /* Read the next value from this entry in aSlot[] */ 225 FifoPage *pNext; /* Next page in the fifo */ 226 i64 aSlot[1]; /* One or more slots for rowid values */ 227 }; 228 229 /* 230 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation 231 ** of that structure is private to this file. 232 ** 233 ** The Fifo structure describes the entire fifo. 234 */ 235 typedef struct Fifo Fifo; 236 struct Fifo { 237 int nEntry; /* Total number of entries */ 238 FifoPage *pFirst; /* First page on the list */ 239 FifoPage *pLast; /* Last page on the list */ 240 }; 241 242 /* 243 ** A Context stores the last insert rowid, the last statement change count, 244 ** and the current statement change count (i.e. changes since last statement). 245 ** The current keylist is also stored in the context. 246 ** Elements of Context structure type make up the ContextStack, which is 247 ** updated by the ContextPush and ContextPop opcodes (used by triggers). 248 ** The context is pushed before executing a trigger a popped when the 249 ** trigger finishes. 250 */ 251 typedef struct Context Context; 252 struct Context { 253 int lastRowid; /* Last insert rowid (sqlite3.lastRowid) */ 254 int nChange; /* Statement changes (Vdbe.nChanges) */ 255 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */ 256 }; 257 258 /* 259 ** An instance of the virtual machine. This structure contains the complete 260 ** state of the virtual machine. 261 ** 262 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 263 ** is really a pointer to an instance of this structure. 264 */ 265 struct Vdbe { 266 sqlite3 *db; /* The whole database */ 267 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 268 FILE *trace; /* Write an execution trace here, if not NULL */ 269 int nOp; /* Number of instructions in the program */ 270 int nOpAlloc; /* Number of slots allocated for aOp[] */ 271 Op *aOp; /* Space to hold the virtual machine's program */ 272 int nLabel; /* Number of labels used */ 273 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 274 int *aLabel; /* Space to hold the labels */ 275 Mem *aStack; /* The operand stack, except string values */ 276 Mem *pTos; /* Top entry in the operand stack */ 277 Mem **apArg; /* Arguments to currently executing user function */ 278 Mem *aColName; /* Column names to return */ 279 int nCursor; /* Number of slots in apCsr[] */ 280 Cursor **apCsr; /* One element of this array for each open cursor */ 281 int nVar; /* Number of entries in aVar[] */ 282 Mem *aVar; /* Values for the OP_Variable opcode. */ 283 char **azVar; /* Name of variables */ 284 int okVar; /* True if azVar[] has been initialized */ 285 int magic; /* Magic number for sanity checking */ 286 int nMem; /* Number of memory locations currently allocated */ 287 Mem *aMem; /* The memory locations */ 288 int nCallback; /* Number of callbacks invoked so far */ 289 Fifo sFifo; /* A list of ROWIDs */ 290 int contextStackTop; /* Index of top element in the context stack */ 291 int contextStackDepth; /* The size of the "context" stack */ 292 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ 293 int pc; /* The program counter */ 294 int rc; /* Value to return */ 295 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */ 296 int errorAction; /* Recovery action to do in case of an error */ 297 int inTempTrans; /* True if temp database is transactioned */ 298 int returnStack[100]; /* Return address stack for OP_Gosub & OP_Return */ 299 int returnDepth; /* Next unused element in returnStack[] */ 300 int nResColumn; /* Number of columns in one row of the result set */ 301 char **azResColumn; /* Values for one row of result */ 302 int popStack; /* Pop the stack this much on entry to VdbeExec() */ 303 char *zErrMsg; /* Error message written here */ 304 u8 resOnStack; /* True if there are result values on the stack */ 305 u8 explain; /* True if EXPLAIN present on SQL command */ 306 u8 changeCntOn; /* True to update the change-counter */ 307 u8 aborted; /* True if ROLLBACK in another VM causes an abort */ 308 u8 expired; /* True if the VM needs to be recompiled */ 309 int nChange; /* Number of db changes made since last reset */ 310 i64 startTime; /* Time when query started - used for profiling */ 311 }; 312 313 /* 314 ** The following are allowed values for Vdbe.magic 315 */ 316 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 317 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 318 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 319 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 320 321 /* 322 ** Function prototypes 323 */ 324 void sqlite3VdbeFreeCursor(Cursor*); 325 void sqliteVdbePopStack(Vdbe*,int); 326 int sqlite3VdbeCursorMoveto(Cursor*); 327 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) 328 void sqlite3VdbePrintOp(FILE*, int, Op*); 329 #endif 330 #ifdef SQLITE_DEBUG 331 void sqlite3VdbePrintSql(Vdbe*); 332 #endif 333 int sqlite3VdbeSerialTypeLen(u32); 334 u32 sqlite3VdbeSerialType(Mem*); 335 int sqlite3VdbeSerialPut(unsigned char*, Mem*); 336 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 337 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); 338 339 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 340 int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*); 341 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 342 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 343 int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*); 344 int sqlite3VdbeIdxRowidLen(int,const u8*); 345 int sqlite3VdbeExec(Vdbe*); 346 int sqlite3VdbeList(Vdbe*); 347 int sqlite3VdbeHalt(Vdbe*); 348 int sqlite3VdbeChangeEncoding(Mem *, int); 349 int sqlite3VdbeMemCopy(Mem*, const Mem*); 350 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); 351 int sqlite3VdbeMemMove(Mem*, Mem*); 352 int sqlite3VdbeMemNulTerminate(Mem*); 353 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); 354 void sqlite3VdbeMemSetInt64(Mem*, i64); 355 void sqlite3VdbeMemSetDouble(Mem*, double); 356 void sqlite3VdbeMemSetNull(Mem*); 357 int sqlite3VdbeMemMakeWriteable(Mem*); 358 int sqlite3VdbeMemDynamicify(Mem*); 359 int sqlite3VdbeMemStringify(Mem*, int); 360 i64 sqlite3VdbeIntValue(Mem*); 361 int sqlite3VdbeMemIntegerify(Mem*); 362 double sqlite3VdbeRealValue(Mem*); 363 int sqlite3VdbeMemRealify(Mem*); 364 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 365 void sqlite3VdbeMemRelease(Mem *p); 366 void sqlite3VdbeMemFinalize(Mem*, FuncDef*); 367 #ifndef NDEBUG 368 void sqlite3VdbeMemSanity(Mem*, u8); 369 int sqlite3VdbeOpcodeNoPush(u8); 370 #endif 371 int sqlite3VdbeMemTranslate(Mem*, u8); 372 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf, int nBuf); 373 int sqlite3VdbeMemHandleBom(Mem *pMem); 374 void sqlite3VdbeFifoInit(Fifo*); 375 int sqlite3VdbeFifoPush(Fifo*, i64); 376 int sqlite3VdbeFifoPop(Fifo*, i64*); 377 void sqlite3VdbeFifoClear(Fifo*); 378