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.
18 ** $Id: vdbeInt.h,v 1.155 2008/10/07 23:46:38 drh Exp $
24 ** intToKey() and keyToInt() used to transform the rowid. But with
25 ** the latest versions of the design they are no-ops.
27 #define keyToInt(X) (X)
28 #define intToKey(X) (X)
32 ** SQL is translated into a sequence of instructions to be
33 ** executed by a virtual machine. Each instruction is an instance
34 ** of the following structure.
36 typedef struct VdbeOp Op;
41 typedef unsigned char Bool;
44 ** A cursor is a pointer into a single BTree within a database file.
45 ** The cursor can seek to a BTree entry with a particular key, or
46 ** loop over all entries of the Btree. You can also insert new BTree
47 ** entries or retrieve the key or data from the entry that the cursor
48 ** is currently pointing to.
50 ** Every cursor that the virtual machine has open is represented by an
51 ** instance of the following structure.
53 ** If the Cursor.isTriggerRow flag is set it means that this cursor is
54 ** really a single row that represents the NEW or OLD pseudo-table of
55 ** a row trigger. The data for the row is stored in Cursor.pData and
56 ** the rowid is in Cursor.iKey.
59 BtCursor *pCursor; /* The cursor structure of the backend */
60 int iDb; /* Index of cursor database in db->aDb[] (or -1) */
61 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */
62 i64 nextRowid; /* Next rowid returned by OP_NewRowid */
63 Bool zeroed; /* True if zeroed out and ready for reuse */
64 Bool rowidIsValid; /* True if lastRowid is valid */
65 Bool atFirst; /* True if pointing to first entry */
66 Bool useRandomRowid; /* Generate new record numbers semi-randomly */
67 Bool nullRow; /* True if pointing to a row with no data */
68 Bool nextRowidValid; /* True if the nextRowid field is valid */
69 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */
70 Bool ephemPseudoTable;
71 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */
72 Bool isTable; /* True if a table requiring integer keys */
73 Bool isIndex; /* True if an index containing keys only - no data */
74 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
75 Btree *pBt; /* Separate file holding temporary table */
76 int nData; /* Number of bytes in pData */
77 char *pData; /* Data for a NEW or OLD pseudo-table */
78 i64 iKey; /* Key for the NEW or OLD pseudo-table row */
79 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */
80 int nField; /* Number of fields in the header */
81 i64 seqCount; /* Sequence counter */
82 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */
83 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */
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 ** aRow might point to (ephemeral) data for the current row, or it might
90 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */
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 */
96 typedef struct Cursor Cursor;
99 ** A value for Cursor.cacheValid that means the cache is always invalid.
101 #define CACHE_STALE 0
104 ** Internally, the vdbe manipulates nearly all SQL values as Mem
105 ** structures. Each Mem struct may cache multiple representations (string,
106 ** integer etc.) of the same value. A value (and therefore Mem structure)
107 ** has the following properties:
109 ** Each value has a manifest type. The manifest type of the value stored
110 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is
111 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or
116 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */
117 FuncDef *pDef; /* Used only when flags==MEM_Agg */
119 double r; /* Real value */
120 sqlite3 *db; /* The associated database connection */
121 char *z; /* String or BLOB value */
122 int n; /* Number of characters in string value, excluding '\0' */
123 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
124 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */
125 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
126 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */
127 char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */
130 /* One or more of the following flags are set to indicate the validOK
131 ** representations of the value stored in the Mem struct.
133 ** If the MEM_Null flag is set, then the value is an SQL NULL value.
134 ** No other flags may be set in this case.
136 ** If the MEM_Str flag is set then Mem.z points at a string representation.
137 ** Usually this is encoded in the same unicode encoding as the main
138 ** database (see below for exceptions). If the MEM_Term flag is also
139 ** set, then the string is nul terminated. The MEM_Int and MEM_Real
140 ** flags may coexist with the MEM_Str flag.
142 ** Multiple of these values can appear in Mem.flags. But only one
143 ** at a time can appear in Mem.type.
145 #define MEM_Null 0x0001 /* Value is NULL */
146 #define MEM_Str 0x0002 /* Value is a string */
147 #define MEM_Int 0x0004 /* Value is an integer */
148 #define MEM_Real 0x0008 /* Value is a real number */
149 #define MEM_Blob 0x0010 /* Value is a BLOB */
151 #define MemSetTypeFlag(p, f) \
152 ((p)->flags = ((p)->flags&~(MEM_Int|MEM_Real|MEM_Null|MEM_Blob|MEM_Str))|f)
154 /* Whenever Mem contains a valid string or blob representation, one of
155 ** the following flags must be set to determine the memory management
156 ** policy for Mem.z. The MEM_Term flag tells us whether or not the
157 ** string is \000 or \u0000 terminated
159 #define MEM_Term 0x0020 /* String rep is nul terminated */
160 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */
161 #define MEM_Static 0x0080 /* Mem.z points to a static string */
162 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */
163 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */
164 #define MEM_Zero 0x0800 /* Mem.i contains count of 0s appended to blob */
166 #ifdef SQLITE_OMIT_INCRBLOB
168 #define MEM_Zero 0x0000
172 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains
173 ** additional information about auxiliary information bound to arguments
174 ** of the function. This is used to implement the sqlite3_get_auxdata()
175 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data
176 ** that can be associated with a constant argument to a function. This
177 ** allows functions such as "regexp" to compile their constant regular
178 ** expression argument once and reused the compiled code for multiple
182 FuncDef *pFunc; /* The definition of the function */
183 int nAux; /* Number of entries allocated for apAux[] */
185 void *pAux; /* Aux data for the i-th argument */
186 void (*xDelete)(void *); /* Destructor for the aux data */
187 } apAux[1]; /* One slot for each function argument */
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.
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.
200 ** This structure is defined inside of vdbeInt.h because it uses substructures
201 ** (Mem) which are only defined there.
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 Mem *pMem; /* Memory cell used to store aggregate context */
208 int isError; /* Error code returned by the function. */
209 CollSeq *pColl; /* Collating sequence */
213 ** A Set structure is used for quick testing to see if a value
214 ** is part of a small set. Sets are used to implement code like
216 ** x.y IN ('hi','hoo','hum')
218 typedef struct Set Set;
220 Hash hash; /* A set is just a hash table */
221 HashElem *prev; /* Previously accessed hash elemen */
225 ** A FifoPage structure holds a single page of valves. Pages are arranged
228 typedef struct FifoPage FifoPage;
230 int nSlot; /* Number of entries aSlot[] */
231 int iWrite; /* Push the next value into this entry in aSlot[] */
232 int iRead; /* Read the next value from this entry in aSlot[] */
233 FifoPage *pNext; /* Next page in the fifo */
234 i64 aSlot[1]; /* One or more slots for rowid values */
238 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation
239 ** of that structure is private to this file.
241 ** The Fifo structure describes the entire fifo.
243 typedef struct Fifo Fifo;
245 int nEntry; /* Total number of entries */
246 sqlite3 *db; /* The associated database connection */
247 FifoPage *pFirst; /* First page on the list */
248 FifoPage *pLast; /* Last page on the list */
252 ** A Context stores the last insert rowid, the last statement change count,
253 ** and the current statement change count (i.e. changes since last statement).
254 ** The current keylist is also stored in the context.
255 ** Elements of Context structure type make up the ContextStack, which is
256 ** updated by the ContextPush and ContextPop opcodes (used by triggers).
257 ** The context is pushed before executing a trigger a popped when the
260 typedef struct Context Context;
262 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */
263 int nChange; /* Statement changes (Vdbe.nChanges) */
264 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */
268 ** An instance of the virtual machine. This structure contains the complete
269 ** state of the virtual machine.
271 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile()
272 ** is really a pointer to an instance of this structure.
274 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of
275 ** any virtual table method invocations made by the vdbe program. It is
276 ** set to 2 for xDestroy method calls and 1 for all other methods. This
277 ** variable is used for two purposes: to allow xDestroy methods to execute
278 ** "DROP TABLE" statements and to prevent some nasty side effects of
279 ** malloc failure when SQLite is invoked recursively by a virtual table
283 sqlite3 *db; /* The whole database */
284 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
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 **apArg; /* Arguments to currently executing user function */
292 Mem *aColName; /* Column names to return */
293 int nCursor; /* Number of slots in apCsr[] */
294 Cursor **apCsr; /* One element of this array for each open cursor */
295 int nVar; /* Number of entries in aVar[] */
296 Mem *aVar; /* Values for the OP_Variable opcode. */
297 char **azVar; /* Name of variables */
298 int okVar; /* True if azVar[] has been initialized */
299 int magic; /* Magic number for sanity checking */
300 int nMem; /* Number of memory locations currently allocated */
301 Mem *aMem; /* The memory locations */
302 int nCallback; /* Number of callbacks invoked so far */
303 int cacheCtr; /* Cursor row cache generation counter */
304 Fifo sFifo; /* A list of ROWIDs */
305 int contextStackTop; /* Index of top element in the context stack */
306 int contextStackDepth; /* The size of the "context" stack */
307 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/
308 int pc; /* The program counter */
309 int rc; /* Value to return */
310 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */
311 int errorAction; /* Recovery action to do in case of an error */
312 int inTempTrans; /* True if temp database is transactioned */
313 int nResColumn; /* Number of columns in one row of the result set */
314 char **azResColumn; /* Values for one row of result */
315 char *zErrMsg; /* Error message written here */
316 Mem *pResultSet; /* Pointer to an array of results */
317 u8 explain; /* True if EXPLAIN present on SQL command */
318 u8 changeCntOn; /* True to update the change-counter */
319 u8 expired; /* True if the VM needs to be recompiled */
320 u8 minWriteFileFormat; /* Minimum file format for writable database files */
321 u8 inVtabMethod; /* See comments above */
322 int nChange; /* Number of db changes made since last reset */
323 i64 startTime; /* Time when query started - used for profiling */
324 int btreeMask; /* Bitmask of db->aDb[] entries referenced */
325 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
326 int aCounter[2]; /* Counters used by sqlite3_stmt_status() */
327 int nSql; /* Number of bytes in zSql */
328 char *zSql; /* Text of the SQL statement that generated this */
330 FILE *trace; /* Write an execution trace here, if not NULL */
332 int openedStatement; /* True if this VM has opened a statement journal */
334 int fetchId; /* Statement number used by sqlite3_fetch_statement */
335 int lru; /* Counter used for LRU cache replacement */
337 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
344 ** The following are allowed values for Vdbe.magic
346 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */
347 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */
348 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */
349 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */
352 ** Function prototypes
354 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*);
355 void sqliteVdbePopStack(Vdbe*,int);
356 int sqlite3VdbeCursorMoveto(Cursor*);
357 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
358 void sqlite3VdbePrintOp(FILE*, int, Op*);
360 int sqlite3VdbeSerialTypeLen(u32);
361 u32 sqlite3VdbeSerialType(Mem*, int);
362 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int);
363 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
364 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
366 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
367 int sqlite3VdbeIdxKeyCompare(Cursor*,UnpackedRecord*,int*);
368 int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
369 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
370 int sqlite3VdbeExec(Vdbe*);
371 int sqlite3VdbeList(Vdbe*);
372 int sqlite3VdbeHalt(Vdbe*);
373 int sqlite3VdbeChangeEncoding(Mem *, int);
374 int sqlite3VdbeMemTooBig(Mem*);
375 int sqlite3VdbeMemCopy(Mem*, const Mem*);
376 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
377 void sqlite3VdbeMemMove(Mem*, Mem*);
378 int sqlite3VdbeMemNulTerminate(Mem*);
379 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
380 void sqlite3VdbeMemSetInt64(Mem*, i64);
381 void sqlite3VdbeMemSetDouble(Mem*, double);
382 void sqlite3VdbeMemSetNull(Mem*);
383 void sqlite3VdbeMemSetZeroBlob(Mem*,int);
384 int sqlite3VdbeMemMakeWriteable(Mem*);
385 int sqlite3VdbeMemStringify(Mem*, int);
386 i64 sqlite3VdbeIntValue(Mem*);
387 int sqlite3VdbeMemIntegerify(Mem*);
388 double sqlite3VdbeRealValue(Mem*);
389 void sqlite3VdbeIntegerAffinity(Mem*);
390 int sqlite3VdbeMemRealify(Mem*);
391 int sqlite3VdbeMemNumerify(Mem*);
392 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
393 void sqlite3VdbeMemRelease(Mem *p);
394 void sqlite3VdbeMemReleaseExternal(Mem *p);
395 int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
396 const char *sqlite3OpcodeName(int);
397 int sqlite3VdbeOpcodeHasProperty(int, int);
398 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
399 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
400 int sqlite3VdbeReleaseBuffers(Vdbe *p);
404 void sqlite3VdbeMemSanity(Mem*);
406 int sqlite3VdbeMemTranslate(Mem*, u8);
408 void sqlite3VdbePrintSql(Vdbe*);
409 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
411 int sqlite3VdbeMemHandleBom(Mem *pMem);
412 void sqlite3VdbeFifoInit(Fifo*, sqlite3*);
413 int sqlite3VdbeFifoPush(Fifo*, i64);
414 int sqlite3VdbeFifoPop(Fifo*, i64*);
415 void sqlite3VdbeFifoClear(Fifo*);
417 #ifndef SQLITE_OMIT_INCRBLOB
418 int sqlite3VdbeMemExpandBlob(Mem *);
420 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
423 #endif /* !defined(_VDBEINT_H_) */