4 ** The author disclaims copyright to this source code. In place of
5 ** a legal notice, here is a blessing:
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.
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.
22 ** intToKey() and keyToInt() used to transform the rowid. But with
23 ** the latest versions of the design they are no-ops.
25 #define keyToInt(X) (X)
26 #define intToKey(X) (X)
30 ** SQL is translated into a sequence of instructions to be
31 ** executed by a virtual machine. Each instruction is an instance
32 ** of the following structure.
34 typedef struct VdbeOp Op;
39 typedef unsigned char Bool;
42 ** A cursor is a pointer into a single BTree within a database file.
43 ** The cursor can seek to a BTree entry with a particular key, or
44 ** loop over all entries of the Btree. You can also insert new BTree
45 ** entries or retrieve the key or data from the entry that the cursor
46 ** is currently pointing to.
48 ** Every cursor that the virtual machine has open is represented by an
49 ** instance of the following structure.
51 ** If the Cursor.isTriggerRow flag is set it means that this cursor is
52 ** really a single row that represents the NEW or OLD pseudo-table of
53 ** a row trigger. The data for the row is stored in Cursor.pData and
54 ** the rowid is in Cursor.iKey.
57 BtCursor *pCursor; /* The cursor structure of the backend */
58 int iDb; /* Index of cursor database in db->aDb[] (or -1) */
59 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */
60 i64 nextRowid; /* Next rowid returned by OP_NewRowid */
61 Bool zeroed; /* True if zeroed out and ready for reuse */
62 Bool rowidIsValid; /* True if lastRowid is valid */
63 Bool atFirst; /* True if pointing to first entry */
64 Bool useRandomRowid; /* Generate new record numbers semi-randomly */
65 Bool nullRow; /* True if pointing to a row with no data */
66 Bool nextRowidValid; /* True if the nextRowid field is valid */
67 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */
68 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */
69 Bool isTable; /* True if a table requiring integer keys */
70 Bool isIndex; /* True if an index containing keys only - no data */
71 u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */
72 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
73 Btree *pBt; /* Separate file holding temporary table */
74 int nData; /* Number of bytes in pData */
75 char *pData; /* Data for a NEW or OLD pseudo-table */
76 i64 iKey; /* Key for the NEW or OLD pseudo-table row */
77 u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */
78 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */
79 int nField; /* Number of fields in the header */
80 i64 seqCount; /* Sequence counter */
81 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */
82 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */
84 /* Cached information about the header for the data record that the
85 ** cursor is currently pointing to. Only valid if cacheValid is true.
86 ** aRow might point to (ephemeral) data for the current row, or it might
89 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */
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 */
95 typedef struct Cursor Cursor;
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
105 ** A value for Cursor.cacheValid that means the cache is always invalid.
107 #define CACHE_STALE 0
110 ** Internally, the vdbe manipulates nearly all SQL values as Mem
111 ** structures. Each Mem struct may cache multiple representations (string,
112 ** integer etc.) of the same value. A value (and therefore Mem structure)
113 ** has the following properties:
115 ** Each value has a manifest type. The manifest type of the value stored
116 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is
117 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or
122 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */
123 FuncDef *pDef; /* Used only when flags==MEM_Agg */
125 double r; /* Real value */
126 sqlite3 *db; /* The associated database connection */
127 char *z; /* String or BLOB value */
128 int n; /* Number of characters in string value, including '\0' */
129 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
130 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */
131 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
132 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */
133 char zShort[NBFS]; /* Space for short strings */
135 typedef struct Mem Mem;
137 /* One or more of the following flags are set to indicate the validOK
138 ** representations of the value stored in the Mem struct.
140 ** If the MEM_Null flag is set, then the value is an SQL NULL value.
141 ** No other flags may be set in this case.
143 ** If the MEM_Str flag is set then Mem.z points at a string representation.
144 ** Usually this is encoded in the same unicode encoding as the main
145 ** database (see below for exceptions). If the MEM_Term flag is also
146 ** set, then the string is nul terminated. The MEM_Int and MEM_Real
147 ** flags may coexist with the MEM_Str flag.
149 ** Multiple of these values can appear in Mem.flags. But only one
150 ** at a time can appear in Mem.type.
152 #define MEM_Null 0x0001 /* Value is NULL */
153 #define MEM_Str 0x0002 /* Value is a string */
154 #define MEM_Int 0x0004 /* Value is an integer */
155 #define MEM_Real 0x0008 /* Value is a real number */
156 #define MEM_Blob 0x0010 /* Value is a BLOB */
158 /* Whenever Mem contains a valid string or blob representation, one of
159 ** the following flags must be set to determine the memory management
160 ** policy for Mem.z. The MEM_Term flag tells us whether or not the
161 ** string is \000 or \u0000 terminated
163 #define MEM_Term 0x0020 /* String rep is nul terminated */
164 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */
165 #define MEM_Static 0x0080 /* Mem.z points to a static string */
166 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */
167 #define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */
168 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */
169 #define MEM_Zero 0x0800 /* Mem.i contains count of 0s appended to blob */
171 #ifdef SQLITE_OMIT_INCRBLOB
173 #define MEM_Zero 0x0000
177 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains
178 ** additional information about auxiliary information bound to arguments
179 ** of the function. This is used to implement the sqlite3_get_auxdata()
180 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data
181 ** that can be associated with a constant argument to a function. This
182 ** allows functions such as "regexp" to compile their constant regular
183 ** expression argument once and reused the compiled code for multiple
187 FuncDef *pFunc; /* The definition of the function */
188 int nAux; /* Number of entries allocated for apAux[] */
190 void *pAux; /* Aux data for the i-th argument */
191 void (*xDelete)(void *); /* Destructor for the aux data */
192 } apAux[1]; /* One slot for each function argument */
194 typedef struct VdbeFunc VdbeFunc;
197 ** The "context" argument for a installable function. A pointer to an
198 ** instance of this structure is the first argument to the routines used
199 ** implement the SQL functions.
201 ** There is a typedef for this structure in sqlite.h. So all routines,
202 ** even the public interface to SQLite, can use a pointer to this structure.
203 ** But this file is the only place where the internal details of this
204 ** structure are known.
206 ** This structure is defined inside of vdbeInt.h because it uses substructures
207 ** (Mem) which are only defined there.
209 struct sqlite3_context {
210 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */
211 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */
212 Mem s; /* The return value is stored here */
213 Mem *pMem; /* Memory cell used to store aggregate context */
214 u8 isError; /* Set to true for an error */
215 CollSeq *pColl; /* Collating sequence */
219 ** A Set structure is used for quick testing to see if a value
220 ** is part of a small set. Sets are used to implement code like
222 ** x.y IN ('hi','hoo','hum')
224 typedef struct Set Set;
226 Hash hash; /* A set is just a hash table */
227 HashElem *prev; /* Previously accessed hash elemen */
231 ** A FifoPage structure holds a single page of valves. Pages are arranged
234 typedef struct FifoPage FifoPage;
236 int nSlot; /* Number of entries aSlot[] */
237 int iWrite; /* Push the next value into this entry in aSlot[] */
238 int iRead; /* Read the next value from this entry in aSlot[] */
239 FifoPage *pNext; /* Next page in the fifo */
240 i64 aSlot[1]; /* One or more slots for rowid values */
244 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation
245 ** of that structure is private to this file.
247 ** The Fifo structure describes the entire fifo.
249 typedef struct Fifo Fifo;
251 int nEntry; /* Total number of entries */
252 FifoPage *pFirst; /* First page on the list */
253 FifoPage *pLast; /* Last page on the list */
257 ** A Context stores the last insert rowid, the last statement change count,
258 ** and the current statement change count (i.e. changes since last statement).
259 ** The current keylist is also stored in the context.
260 ** Elements of Context structure type make up the ContextStack, which is
261 ** updated by the ContextPush and ContextPop opcodes (used by triggers).
262 ** The context is pushed before executing a trigger a popped when the
265 typedef struct Context Context;
267 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */
268 int nChange; /* Statement changes (Vdbe.nChanges) */
269 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */
273 ** An instance of the virtual machine. This structure contains the complete
274 ** state of the virtual machine.
276 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile()
277 ** is really a pointer to an instance of this structure.
279 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of
280 ** any virtual table method invocations made by the vdbe program. It is
281 ** set to 2 for xDestroy method calls and 1 for all other methods. This
282 ** variable is used for two purposes: to allow xDestroy methods to execute
283 ** "DROP TABLE" statements and to prevent some nasty side effects of
284 ** malloc failure when SQLite is invoked recursively by a virtual table
288 sqlite3 *db; /* The whole database */
289 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
290 int nOp; /* Number of instructions in the program */
291 int nOpAlloc; /* Number of slots allocated for aOp[] */
292 Op *aOp; /* Space to hold the virtual machine's program */
293 int nLabel; /* Number of labels used */
294 int nLabelAlloc; /* Number of slots allocated in aLabel[] */
295 int *aLabel; /* Space to hold the labels */
296 Mem *aStack; /* The operand stack, except string values */
297 Mem *pTos; /* Top entry in the operand stack */
298 Mem **apArg; /* Arguments to currently executing user function */
299 Mem *aColName; /* Column names to return */
300 int nCursor; /* Number of slots in apCsr[] */
301 Cursor **apCsr; /* One element of this array for each open cursor */
302 int nVar; /* Number of entries in aVar[] */
303 Mem *aVar; /* Values for the OP_Variable opcode. */
304 char **azVar; /* Name of variables */
305 int okVar; /* True if azVar[] has been initialized */
306 int magic; /* Magic number for sanity checking */
307 int nMem; /* Number of memory locations currently allocated */
308 Mem *aMem; /* The memory locations */
309 int nCallback; /* Number of callbacks invoked so far */
310 int cacheCtr; /* Cursor row cache generation counter */
311 Fifo sFifo; /* A list of ROWIDs */
312 int contextStackTop; /* Index of top element in the context stack */
313 int contextStackDepth; /* The size of the "context" stack */
314 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/
315 int pc; /* The program counter */
316 int rc; /* Value to return */
317 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */
318 int errorAction; /* Recovery action to do in case of an error */
319 int inTempTrans; /* True if temp database is transactioned */
320 int returnStack[25]; /* Return address stack for OP_Gosub & OP_Return */
321 int returnDepth; /* Next unused element in returnStack[] */
322 int nResColumn; /* Number of columns in one row of the result set */
323 char **azResColumn; /* Values for one row of result */
324 int popStack; /* Pop the stack this much on entry to VdbeExec() */
325 char *zErrMsg; /* Error message written here */
326 u8 resOnStack; /* True if there are result values on the stack */
327 u8 explain; /* True if EXPLAIN present on SQL command */
328 u8 changeCntOn; /* True to update the change-counter */
329 u8 aborted; /* True if ROLLBACK in another VM causes an abort */
330 u8 expired; /* True if the VM needs to be recompiled */
331 u8 minWriteFileFormat; /* Minimum file format for writable database files */
332 u8 inVtabMethod; /* See comments above */
333 int nChange; /* Number of db changes made since last reset */
334 i64 startTime; /* Time when query started - used for profiling */
335 int btreeMask; /* Bitmask of db->aDb[] entries referenced */
336 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
337 int nSql; /* Number of bytes in zSql */
338 char *zSql; /* Text of the SQL statement that generated this */
340 FILE *trace; /* Write an execution trace here, if not NULL */
342 int openedStatement; /* True if this VM has opened a statement journal */
344 int fetchId; /* Statement number used by sqlite3_fetch_statement */
345 int lru; /* Counter used for LRU cache replacement */
350 ** The following are allowed values for Vdbe.magic
352 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */
353 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */
354 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */
355 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */
358 ** Function prototypes
360 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*);
361 void sqliteVdbePopStack(Vdbe*,int);
362 int sqlite3VdbeCursorMoveto(Cursor*);
363 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
364 void sqlite3VdbePrintOp(FILE*, int, Op*);
366 int sqlite3VdbeSerialTypeLen(u32);
367 u32 sqlite3VdbeSerialType(Mem*, int);
368 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int);
369 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
370 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
372 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
373 int sqlite3VdbeIdxKeyCompare(Cursor*,int,const unsigned char*,int*);
374 int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
375 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
376 int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*);
377 int sqlite3VdbeIdxRowidLen(const u8*);
378 int sqlite3VdbeExec(Vdbe*);
379 int sqlite3VdbeList(Vdbe*);
380 int sqlite3VdbeHalt(Vdbe*);
381 int sqlite3VdbeChangeEncoding(Mem *, int);
382 int sqlite3VdbeMemTooBig(Mem*);
383 int sqlite3VdbeMemCopy(Mem*, const Mem*);
384 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
385 int sqlite3VdbeMemMove(Mem*, Mem*);
386 int sqlite3VdbeMemNulTerminate(Mem*);
387 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
388 void sqlite3VdbeMemSetInt64(Mem*, i64);
389 void sqlite3VdbeMemSetDouble(Mem*, double);
390 void sqlite3VdbeMemSetNull(Mem*);
391 void sqlite3VdbeMemSetZeroBlob(Mem*,int);
392 int sqlite3VdbeMemMakeWriteable(Mem*);
393 int sqlite3VdbeMemDynamicify(Mem*);
394 int sqlite3VdbeMemStringify(Mem*, int);
395 i64 sqlite3VdbeIntValue(Mem*);
396 int sqlite3VdbeMemIntegerify(Mem*);
397 double sqlite3VdbeRealValue(Mem*);
398 void sqlite3VdbeIntegerAffinity(Mem*);
399 int sqlite3VdbeMemRealify(Mem*);
400 int sqlite3VdbeMemNumerify(Mem*);
401 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
402 void sqlite3VdbeMemRelease(Mem *p);
403 int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
404 const char *sqlite3OpcodeName(int);
407 void sqlite3VdbeMemSanity(Mem*);
408 int sqlite3VdbeOpcodeNoPush(u8);
410 int sqlite3VdbeMemTranslate(Mem*, u8);
412 void sqlite3VdbePrintSql(Vdbe*);
413 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
415 int sqlite3VdbeMemHandleBom(Mem *pMem);
416 void sqlite3VdbeFifoInit(Fifo*);
417 int sqlite3VdbeFifoPush(Fifo*, i64);
418 int sqlite3VdbeFifoPop(Fifo*, i64*);
419 void sqlite3VdbeFifoClear(Fifo*);
421 #ifndef SQLITE_OMIT_INCRBLOB
422 int sqlite3VdbeMemExpandBlob(Mem *);
424 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
427 #endif /* !defined(_VDBEINT_H_) */
