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 1.153 2008/08/02 03:50:39 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 u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */
75 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
76 Btree *pBt; /* Separate file holding temporary table */
77 int nData; /* Number of bytes in pData */
78 char *pData; /* Data for a NEW or OLD pseudo-table */
79 i64 iKey; /* Key for the NEW or OLD pseudo-table row */
80 u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */
81 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */
82 int nField; /* Number of fields in the header */
83 i64 seqCount; /* Sequence counter */
84 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */
85 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */
87 /* Cached information about the header for the data record that the
88 ** cursor is currently pointing to. Only valid if cacheValid is true.
89 ** aRow might point to (ephemeral) data for the current row, or it might
92 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */
93 int payloadSize; /* Total number of bytes in the record */
94 u32 *aType; /* Type values for all entries in the record */
95 u32 *aOffset; /* Cached offsets to the start of each columns data */
96 u8 *aRow; /* Data for the current row, if all on one page */
98 typedef struct Cursor Cursor;
101 ** A value for Cursor.cacheValid that means the cache is always invalid.
103 #define CACHE_STALE 0
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:
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
118 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */
119 FuncDef *pDef; /* Used only when flags==MEM_Agg */
121 double r; /* Real value */
122 sqlite3 *db; /* The associated database connection */
123 char *z; /* String or BLOB value */
124 int n; /* Number of characters in string value, excluding '\0' */
125 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
126 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */
127 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
128 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */
129 char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */
132 /* One or more of the following flags are set to indicate the validOK
133 ** representations of the value stored in the Mem struct.
135 ** If the MEM_Null flag is set, then the value is an SQL NULL value.
136 ** No other flags may be set in this case.
138 ** If the MEM_Str flag is set then Mem.z points at a string representation.
139 ** Usually this is encoded in the same unicode encoding as the main
140 ** database (see below for exceptions). If the MEM_Term flag is also
141 ** set, then the string is nul terminated. The MEM_Int and MEM_Real
142 ** flags may coexist with the MEM_Str flag.
144 ** Multiple of these values can appear in Mem.flags. But only one
145 ** at a time can appear in Mem.type.
147 #define MEM_Null 0x0001 /* Value is NULL */
148 #define MEM_Str 0x0002 /* Value is a string */
149 #define MEM_Int 0x0004 /* Value is an integer */
150 #define MEM_Real 0x0008 /* Value is a real number */
151 #define MEM_Blob 0x0010 /* Value is a BLOB */
153 #define MemSetTypeFlag(p, f) \
154 ((p)->flags = ((p)->flags&~(MEM_Int|MEM_Real|MEM_Null|MEM_Blob|MEM_Str))|f)
156 /* Whenever Mem contains a valid string or blob representation, one of
157 ** the following flags must be set to determine the memory management
158 ** policy for Mem.z. The MEM_Term flag tells us whether or not the
159 ** string is \000 or \u0000 terminated
161 #define MEM_Term 0x0020 /* String rep is nul terminated */
162 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */
163 #define MEM_Static 0x0080 /* Mem.z points to a static string */
164 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */
165 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */
166 #define MEM_Zero 0x0800 /* Mem.i contains count of 0s appended to blob */
168 #ifdef SQLITE_OMIT_INCRBLOB
170 #define MEM_Zero 0x0000
174 /* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains
175 ** additional information about auxiliary information bound to arguments
176 ** of the function. This is used to implement the sqlite3_get_auxdata()
177 ** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data
178 ** that can be associated with a constant argument to a function. This
179 ** allows functions such as "regexp" to compile their constant regular
180 ** expression argument once and reused the compiled code for multiple
184 FuncDef *pFunc; /* The definition of the function */
185 int nAux; /* Number of entries allocated for apAux[] */
187 void *pAux; /* Aux data for the i-th argument */
188 void (*xDelete)(void *); /* Destructor for the aux data */
189 } apAux[1]; /* One slot for each function argument */
193 ** The "context" argument for a installable function. A pointer to an
194 ** instance of this structure is the first argument to the routines used
195 ** implement the SQL functions.
197 ** There is a typedef for this structure in sqlite.h. So all routines,
198 ** even the public interface to SQLite, can use a pointer to this structure.
199 ** But this file is the only place where the internal details of this
200 ** structure are known.
202 ** This structure is defined inside of vdbeInt.h because it uses substructures
203 ** (Mem) which are only defined there.
205 struct sqlite3_context {
206 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */
207 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */
208 Mem s; /* The return value is stored here */
209 Mem *pMem; /* Memory cell used to store aggregate context */
210 int isError; /* Error code returned by the function. */
211 CollSeq *pColl; /* Collating sequence */
215 ** A Set structure is used for quick testing to see if a value
216 ** is part of a small set. Sets are used to implement code like
218 ** x.y IN ('hi','hoo','hum')
220 typedef struct Set Set;
222 Hash hash; /* A set is just a hash table */
223 HashElem *prev; /* Previously accessed hash elemen */
227 ** A FifoPage structure holds a single page of valves. Pages are arranged
230 typedef struct FifoPage FifoPage;
232 int nSlot; /* Number of entries aSlot[] */
233 int iWrite; /* Push the next value into this entry in aSlot[] */
234 int iRead; /* Read the next value from this entry in aSlot[] */
235 FifoPage *pNext; /* Next page in the fifo */
236 i64 aSlot[1]; /* One or more slots for rowid values */
240 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation
241 ** of that structure is private to this file.
243 ** The Fifo structure describes the entire fifo.
245 typedef struct Fifo Fifo;
247 int nEntry; /* Total number of entries */
248 sqlite3 *db; /* The associated database connection */
249 FifoPage *pFirst; /* First page on the list */
250 FifoPage *pLast; /* Last page on the list */
254 ** A Context stores the last insert rowid, the last statement change count,
255 ** and the current statement change count (i.e. changes since last statement).
256 ** The current keylist is also stored in the context.
257 ** Elements of Context structure type make up the ContextStack, which is
258 ** updated by the ContextPush and ContextPop opcodes (used by triggers).
259 ** The context is pushed before executing a trigger a popped when the
262 typedef struct Context Context;
264 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */
265 int nChange; /* Statement changes (Vdbe.nChanges) */
266 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */
270 ** An instance of the virtual machine. This structure contains the complete
271 ** state of the virtual machine.
273 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile()
274 ** is really a pointer to an instance of this structure.
276 ** The Vdbe.inVtabMethod variable is set to non-zero for the duration of
277 ** any virtual table method invocations made by the vdbe program. It is
278 ** set to 2 for xDestroy method calls and 1 for all other methods. This
279 ** variable is used for two purposes: to allow xDestroy methods to execute
280 ** "DROP TABLE" statements and to prevent some nasty side effects of
281 ** malloc failure when SQLite is invoked recursively by a virtual table
285 sqlite3 *db; /* The whole database */
286 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
287 int nOp; /* Number of instructions in the program */
288 int nOpAlloc; /* Number of slots allocated for aOp[] */
289 Op *aOp; /* Space to hold the virtual machine's program */
290 int nLabel; /* Number of labels used */
291 int nLabelAlloc; /* Number of slots allocated in aLabel[] */
292 int *aLabel; /* Space to hold the labels */
293 Mem **apArg; /* Arguments to currently executing user function */
294 Mem *aColName; /* Column names to return */
295 int nCursor; /* Number of slots in apCsr[] */
296 Cursor **apCsr; /* One element of this array for each open cursor */
297 int nVar; /* Number of entries in aVar[] */
298 Mem *aVar; /* Values for the OP_Variable opcode. */
299 char **azVar; /* Name of variables */
300 int okVar; /* True if azVar[] has been initialized */
301 int magic; /* Magic number for sanity checking */
302 int nMem; /* Number of memory locations currently allocated */
303 Mem *aMem; /* The memory locations */
304 int nCallback; /* Number of callbacks invoked so far */
305 int cacheCtr; /* Cursor row cache generation counter */
306 Fifo sFifo; /* A list of ROWIDs */
307 int contextStackTop; /* Index of top element in the context stack */
308 int contextStackDepth; /* The size of the "context" stack */
309 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/
310 int pc; /* The program counter */
311 int rc; /* Value to return */
312 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */
313 int errorAction; /* Recovery action to do in case of an error */
314 int inTempTrans; /* True if temp database is transactioned */
315 int nResColumn; /* Number of columns in one row of the result set */
316 char **azResColumn; /* Values for one row of result */
317 char *zErrMsg; /* Error message written here */
318 Mem *pResultSet; /* Pointer to an array of results */
319 u8 explain; /* True if EXPLAIN present on SQL command */
320 u8 changeCntOn; /* True to update the change-counter */
321 u8 expired; /* True if the VM needs to be recompiled */
322 u8 minWriteFileFormat; /* Minimum file format for writable database files */
323 u8 inVtabMethod; /* See comments above */
324 int nChange; /* Number of db changes made since last reset */
325 i64 startTime; /* Time when query started - used for profiling */
326 int btreeMask; /* Bitmask of db->aDb[] entries referenced */
327 BtreeMutexArray aMutex; /* An array of Btree used here and needing locks */
328 int nSql; /* Number of bytes in zSql */
329 char *zSql; /* Text of the SQL statement that generated this */
331 FILE *trace; /* Write an execution trace here, if not NULL */
333 int openedStatement; /* True if this VM has opened a statement journal */
335 int fetchId; /* Statement number used by sqlite3_fetch_statement */
336 int lru; /* Counter used for LRU cache replacement */
338 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
345 ** An instance of the following structure holds information about a
346 ** single index record that has already been parsed out into individual
349 ** A record is an object that contains one or more fields of data.
350 ** Records are used to store the content of a table row and to store
351 ** the key of an index. A blob encoding of a record is created by
352 ** the OP_MakeRecord opcode of the VDBE and is disassemblied by the
355 ** This structure holds a record that has already been disassembled
356 ** into its constitutent fields.
358 struct UnpackedRecord {
359 KeyInfo *pKeyInfo; /* Collation and sort-order information */
360 u16 nField; /* Number of entries in apMem[] */
361 u8 needFree; /* True if memory obtained from sqlite3_malloc() */
362 u8 needDestroy; /* True if apMem[]s should be destroyed on close */
363 Mem *aMem; /* Values */
367 ** The following are allowed values for Vdbe.magic
369 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */
370 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */
371 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */
372 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */
375 ** Function prototypes
377 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*);
378 void sqliteVdbePopStack(Vdbe*,int);
379 int sqlite3VdbeCursorMoveto(Cursor*);
380 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
381 void sqlite3VdbePrintOp(FILE*, int, Op*);
383 int sqlite3VdbeSerialTypeLen(u32);
384 u32 sqlite3VdbeSerialType(Mem*, int);
385 int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int);
386 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
387 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
389 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
390 int sqlite3VdbeIdxKeyCompare(Cursor*,UnpackedRecord *,int,const unsigned char*,int*);
391 int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
392 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
393 int sqlite3VdbeIdxRowidLen(const u8*, int, int*);
394 int sqlite3VdbeExec(Vdbe*);
395 int sqlite3VdbeList(Vdbe*);
396 int sqlite3VdbeHalt(Vdbe*);
397 int sqlite3VdbeChangeEncoding(Mem *, int);
398 int sqlite3VdbeMemTooBig(Mem*);
399 int sqlite3VdbeMemCopy(Mem*, const Mem*);
400 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
401 void sqlite3VdbeMemMove(Mem*, Mem*);
402 int sqlite3VdbeMemNulTerminate(Mem*);
403 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
404 void sqlite3VdbeMemSetInt64(Mem*, i64);
405 void sqlite3VdbeMemSetDouble(Mem*, double);
406 void sqlite3VdbeMemSetNull(Mem*);
407 void sqlite3VdbeMemSetZeroBlob(Mem*,int);
408 int sqlite3VdbeMemMakeWriteable(Mem*);
409 int sqlite3VdbeMemStringify(Mem*, int);
410 i64 sqlite3VdbeIntValue(Mem*);
411 int sqlite3VdbeMemIntegerify(Mem*);
412 double sqlite3VdbeRealValue(Mem*);
413 void sqlite3VdbeIntegerAffinity(Mem*);
414 int sqlite3VdbeMemRealify(Mem*);
415 int sqlite3VdbeMemNumerify(Mem*);
416 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
417 void sqlite3VdbeMemRelease(Mem *p);
418 void sqlite3VdbeMemReleaseExternal(Mem *p);
419 int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
420 const char *sqlite3OpcodeName(int);
421 int sqlite3VdbeOpcodeHasProperty(int, int);
422 int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
423 #ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
424 int sqlite3VdbeReleaseBuffers(Vdbe *p);
428 void sqlite3VdbeMemSanity(Mem*);
430 int sqlite3VdbeMemTranslate(Mem*, u8);
432 void sqlite3VdbePrintSql(Vdbe*);
433 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
435 int sqlite3VdbeMemHandleBom(Mem *pMem);
436 void sqlite3VdbeFifoInit(Fifo*, sqlite3*);
437 int sqlite3VdbeFifoPush(Fifo*, i64);
438 int sqlite3VdbeFifoPop(Fifo*, i64*);
439 void sqlite3VdbeFifoClear(Fifo*);
441 #ifndef SQLITE_OMIT_INCRBLOB
442 int sqlite3VdbeMemExpandBlob(Mem *);
444 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
447 #endif /* !defined(_VDBEINT_H_) */