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 lastRecno; /* Last recno from a Next or NextIdx operation */ 64 i64 nextRowid; /* Next rowid returned by OP_NewRowid */ 65 Bool recnoIsValid; /* True if lastRecno is valid */ 66 Bool keyAsData; /* The OP_Column command works on key instead of data */ 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 intKey; /* True if the table requires integer keys */ 74 Bool zeroData; /* True if table contains 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 */ 87 Bool cacheValid; /* True if the cache is valid */ 88 int payloadSize; /* Total number of bytes in the record */ 89 u32 *aType; /* Type values for all entries in the record */ 90 u32 *aOffset; /* Cached offsets to the start of each columns data */ 91 }; 92 typedef struct Cursor Cursor; 93 94 /* 95 ** A sorter builds a list of elements to be sorted. Each element of 96 ** the list is an instance of the following structure. 97 */ 98 typedef struct Sorter Sorter; 99 struct Sorter { 100 int nKey; /* Number of bytes in the key */ 101 char *zKey; /* The key by which we will sort */ 102 int nData; /* Number of bytes in the data */ 103 char *pData; /* The data associated with this key */ 104 Sorter *pNext; /* Next in the list */ 105 }; 106 107 /* 108 ** Number of buckets used for merge-sort. 109 */ 110 #define NSORT 30 111 112 /* 113 ** Number of bytes of string storage space available to each stack 114 ** layer without having to malloc. NBFS is short for Number of Bytes 115 ** For Strings. 116 */ 117 #define NBFS 32 118 119 /* 120 ** Internally, the vdbe manipulates nearly all SQL values as Mem 121 ** structures. Each Mem struct may cache multiple representations (string, 122 ** integer etc.) of the same value. A value (and therefore Mem structure) 123 ** has the following properties: 124 ** 125 ** Each value has a manifest type. The manifest type of the value stored 126 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is 127 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or 128 ** SQLITE_BLOB. 129 */ 130 struct Mem { 131 i64 i; /* Integer value */ 132 int n; /* Number of characters in string value, including '\0' */ 133 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ 134 u8 type; /* One of MEM_Null, MEM_Str, etc. */ 135 u8 enc; /* TEXT_Utf8, TEXT_Utf16le, or TEXT_Utf16be */ 136 double r; /* Real value */ 137 char *z; /* String or BLOB value */ 138 char zShort[NBFS]; /* Space for short strings */ 139 }; 140 typedef struct Mem Mem; 141 142 /* One or more of the following flags are set to indicate the validOK 143 ** representations of the value stored in the Mem struct. 144 ** 145 ** If the MEM_Null flag is set, then the value is an SQL NULL value. 146 ** No other flags may be set in this case. 147 ** 148 ** If the MEM_Str flag is set then Mem.z points at a string representation. 149 ** Usually this is encoded in the same unicode encoding as the main 150 ** database (see below for exceptions). If the MEM_Term flag is also 151 ** set, then the string is nul terminated. The MEM_Int and MEM_Real 152 ** flags may coexist with the MEM_Str flag. 153 ** 154 ** Multiple of these values can appear in Mem.flags. But only one 155 ** at a time can appear in Mem.type. 156 */ 157 #define MEM_Null 0x0001 /* Value is NULL */ 158 #define MEM_Str 0x0002 /* Value is a string */ 159 #define MEM_Int 0x0004 /* Value is an integer */ 160 #define MEM_Real 0x0008 /* Value is a real number */ 161 #define MEM_Blob 0x0010 /* Value is a BLOB */ 162 163 /* Whenever Mem contains a valid string or blob representation, one of 164 ** the following flags must be set to determine the memory management 165 ** policy for Mem.z. The MEM_Term flag tells us whether or not the 166 ** string is \000 or \u0000 terminated 167 */ 168 #define MEM_Term 0x0020 /* String rep is nul terminated */ 169 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ 170 #define MEM_Static 0x0080 /* Mem.z points to a static string */ 171 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ 172 #define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */ 173 174 /* The following MEM_ value appears only in AggElem.aMem.s.flag fields. 175 ** It indicates that the corresponding AggElem.aMem.z points to a 176 ** aggregate function context that needs to be finalized. 177 */ 178 #define MEM_AggCtx 0x0400 /* Mem.z points to an agg function context */ 179 180 struct VdbeFunc { 181 FuncDef *pFunc; 182 int nAux; 183 struct AuxData { 184 void *pAux; 185 void (*xDelete)(void *); 186 } apAux[0]; 187 }; 188 typedef struct VdbeFunc VdbeFunc; 189 190 /* 191 ** The "context" argument for a installable function. A pointer to an 192 ** instance of this structure is the first argument to the routines used 193 ** implement the SQL functions. 194 ** 195 ** There is a typedef for this structure in sqlite.h. So all routines, 196 ** even the public interface to SQLite, can use a pointer to this structure. 197 ** But this file is the only place where the internal details of this 198 ** structure are known. 199 ** 200 ** This structure is defined inside of vdbe.c because it uses substructures 201 ** (Mem) which are only defined there. 202 */ 203 struct sqlite3_context { 204 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ 205 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ 206 Mem s; /* The return value is stored here */ 207 void *pAgg; /* Aggregate context */ 208 u8 isError; /* Set to true for an error */ 209 u8 isStep; /* Current in the step function */ 210 int cnt; /* Number of times that the step function has been called */ 211 }; 212 213 /* 214 ** An Agg structure describes an Aggregator. Each Agg consists of 215 ** zero or more Aggregator elements (AggElem). Each AggElem contains 216 ** a key and one or more values. The values are used in processing 217 ** aggregate functions in a SELECT. The key is used to implement 218 ** the GROUP BY clause of a select. 219 */ 220 typedef struct Agg Agg; 221 typedef struct AggElem AggElem; 222 struct Agg { 223 int nMem; /* Number of values stored in each AggElem */ 224 AggElem *pCurrent; /* The AggElem currently in focus */ 225 HashElem *pSearch; /* The hash element for pCurrent */ 226 Hash hash; /* Hash table of all aggregate elements */ 227 FuncDef **apFunc; /* Information about aggregate functions */ 228 }; 229 struct AggElem { 230 char *zKey; /* The key to this AggElem */ 231 int nKey; /* Number of bytes in the key, including '\0' at end */ 232 Mem aMem[1]; /* The values for this AggElem */ 233 }; 234 235 /* 236 ** A Set structure is used for quick testing to see if a value 237 ** is part of a small set. Sets are used to implement code like 238 ** this: 239 ** x.y IN ('hi','hoo','hum') 240 */ 241 typedef struct Set Set; 242 struct Set { 243 Hash hash; /* A set is just a hash table */ 244 HashElem *prev; /* Previously accessed hash elemen */ 245 }; 246 247 /* 248 ** A Keylist is a bunch of keys into a table. The keylist can 249 ** grow without bound. The keylist stores the ROWIDs of database 250 ** records that need to be deleted or updated. 251 */ 252 typedef struct Keylist Keylist; 253 struct Keylist { 254 int nKey; /* Number of slots in aKey[] */ 255 int nUsed; /* Next unwritten slot in aKey[] */ 256 int nRead; /* Next unread slot in aKey[] */ 257 Keylist *pNext; /* Next block of keys */ 258 i64 aKey[1]; /* One or more keys. Extra space allocated as needed */ 259 }; 260 261 /* 262 ** A Context stores the last insert rowid, the last statement change count, 263 ** and the current statement change count (i.e. changes since last statement). 264 ** Elements of Context structure type make up the ContextStack, which is 265 ** updated by the ContextPush and ContextPop opcodes (used by triggers) 266 */ 267 typedef struct Context Context; 268 struct Context { 269 int lastRowid; /* Last insert rowid (from db->lastRowid) */ 270 int lsChange; /* Last statement change count (from db->lsChange) */ 271 int csChange; /* Current statement change count (from db->csChange) */ 272 }; 273 274 /* 275 ** An instance of the virtual machine. This structure contains the complete 276 ** state of the virtual machine. 277 ** 278 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() 279 ** is really a pointer to an instance of this structure. 280 */ 281 struct Vdbe { 282 sqlite *db; /* The whole database */ 283 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ 284 FILE *trace; /* Write an execution trace here, if not NULL */ 285 int nOp; /* Number of instructions in the program */ 286 int nOpAlloc; /* Number of slots allocated for aOp[] */ 287 Op *aOp; /* Space to hold the virtual machine's program */ 288 int nLabel; /* Number of labels used */ 289 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ 290 int *aLabel; /* Space to hold the labels */ 291 Mem *aStack; /* The operand stack, except string values */ 292 Mem *pTos; /* Top entry in the operand stack */ 293 Mem **apArg; /* Arguments to currently executing user function */ 294 Mem *aColName; /* Column names to return */ 295 char **azColName; /* Becomes the 4th parameter to callbacks */ 296 void **azColName16; /* UTF-16 encoded equivalent of azColName */ 297 int nCursor; /* Number of slots in apCsr[] */ 298 Cursor **apCsr; /* One element of this array for each open cursor */ 299 Sorter *pSort; /* A linked list of objects to be sorted */ 300 FILE *pFile; /* At most one open file handler */ 301 int nField; /* Number of file fields */ 302 char **azField; /* Data for each file field */ 303 int nVar; /* Number of entries in apVar[] */ 304 Mem *apVar; /* Values for the OP_Variable opcode. */ 305 char *zLine; /* A single line from the input file */ 306 int nLineAlloc; /* Number of spaces allocated for zLine */ 307 int magic; /* Magic number for sanity checking */ 308 int nMem; /* Number of memory locations currently allocated */ 309 Mem *aMem; /* The memory locations */ 310 Agg agg; /* Aggregate information */ 311 int nCallback; /* Number of callbacks invoked so far */ 312 Keylist *pList; /* A list of ROWIDs */ 313 int keylistStackDepth; /* The size of the "keylist" stack */ 314 Keylist **keylistStack; /* The stack used by opcodes ListPush & ListPop */ 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 autoCommitOn; /* True if autocommit got turned on by this program */ 331 }; 332 333 /* 334 ** The following are allowed values for Vdbe.magic 335 */ 336 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ 337 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ 338 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ 339 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ 340 341 /* 342 ** Function prototypes 343 */ 344 void sqlite3VdbeCleanupCursor(Cursor*); 345 void sqlite3VdbeSorterReset(Vdbe*); 346 void sqlite3VdbeAggReset(Agg*); 347 void sqlite3VdbeKeylistFree(Keylist*); 348 void sqliteVdbePopStack(Vdbe*,int); 349 int sqlite3VdbeCursorMoveto(Cursor*); 350 #if !defined(NDEBUG) || defined(VDBE_PROFILE) 351 void sqlite3VdbePrintOp(FILE*, int, Op*); 352 #endif 353 int sqlite3VdbeSerialTypeLen(u32); 354 u32 sqlite3VdbeSerialType(Mem*); 355 int sqlite3VdbeSerialPut(unsigned char*, Mem*); 356 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); 357 358 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); 359 int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*); 360 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); 361 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); 362 int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*); 363 int sqlite3VdbeIdxRowidLen(int,const u8*); 364 int sqlite3VdbeExec(Vdbe*); 365 int sqlite3VdbeList(Vdbe*); 366 int sqlite3VdbeChangeEncoding(Mem *, int); 367 int sqlite3VdbeMemCopy(Mem*, const Mem*); 368 int sqlite3VdbeMemNulTerminate(Mem*); 369 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, int); 370 void sqlite3VdbeMemSetInt64(Mem*, long long int); 371 void sqlite3VdbeMemSetDouble(Mem*, double); 372 void sqlite3VdbeMemSetNull(Mem*); 373 int sqlite3VdbeMemMakeWriteable(Mem*); 374 int sqlite3VdbeMemDynamicify(Mem*); 375 int sqlite3VdbeMemStringify(Mem*, int); 376 int sqlite3VdbeMemIntegerify(Mem*); 377 int sqlite3VdbeMemRealify(Mem*); 378 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); 379 #ifndef NDEBUG 380 void sqlite3VdbeMemSanity(Mem*, u8); 381 #endif 382