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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#ifndef _VDBEINT_H_
19#define _VDBEINT_H_
20
21/*
22** intToKey() and keyToInt() used to transform the rowid. But with
23** the latest versions of the design they are no-ops.
24*/
25#define keyToInt(X) (X)
26#define intToKey(X) (X)
27
28/*
29** The makefile scans the vdbe.c source file and creates the following
30** array of string constants which are the names of all VDBE opcodes. This
31** array is defined in a separate source code file named opcode.c which is
32** automatically generated by the makefile.
33*/
34extern const char *const sqlite3OpcodeNames[];
35
36/*
37** SQL is translated into a sequence of instructions to be
38** executed by a virtual machine. Each instruction is an instance
39** of the following structure.
40*/
41typedef struct VdbeOp Op;
42
43/*
44** Boolean values
45*/
46typedef unsigned char Bool;
47
48/*
49** A cursor is a pointer into a single BTree within a database file.
50** The cursor can seek to a BTree entry with a particular key, or
51** loop over all entries of the Btree. You can also insert new BTree
52** entries or retrieve the key or data from the entry that the cursor
53** is currently pointing to.
54**
55** Every cursor that the virtual machine has open is represented by an
56** instance of the following structure.
57**
58** If the Cursor.isTriggerRow flag is set it means that this cursor is
59** really a single row that represents the NEW or OLD pseudo-table of
60** a row trigger. The data for the row is stored in Cursor.pData and
61** the rowid is in Cursor.iKey.
62*/
63struct Cursor {
64 BtCursor *pCursor; /* The cursor structure of the backend */
65 int iDb; /* Index of cursor database in db->aDb[] (or -1) */
66 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */
67 i64 nextRowid; /* Next rowid returned by OP_NewRowid */
68 Bool zeroed; /* True if zeroed out and ready for reuse */
69 Bool rowidIsValid; /* True if lastRowid is valid */
70 Bool atFirst; /* True if pointing to first entry */
71 Bool useRandomRowid; /* Generate new record numbers semi-randomly */
72 Bool nullRow; /* True if pointing to a row with no data */
73 Bool nextRowidValid; /* True if the nextRowid field is valid */
74 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */
75 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */
76 Bool isTable; /* True if a table requiring integer keys */
77 Bool isIndex; /* True if an index containing keys only - no data */
78 u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */
79 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
80 Btree *pBt; /* Separate file holding temporary table */
81 int nData; /* Number of bytes in pData */
82 char *pData; /* Data for a NEW or OLD pseudo-table */
83 i64 iKey; /* Key for the NEW or OLD pseudo-table row */
84 u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */
85 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */
86 int nField; /* Number of fields in the header */
87 i64 seqCount; /* Sequence counter */
88 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */
89 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */
90
91 /* Cached information about the header for the data record that the
92 ** cursor is currently pointing to. Only valid if cacheValid is true.
93 ** aRow might point to (ephemeral) data for the current row, or it might
94 ** be NULL.
95 */
96 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */
97 int payloadSize; /* Total number of bytes in the record */
98 u32 *aType; /* Type values for all entries in the record */
99 u32 *aOffset; /* Cached offsets to the start of each columns data */
100 u8 *aRow; /* Data for the current row, if all on one page */
101};
102typedef struct Cursor Cursor;
103
104/*
105** Number of bytes of string storage space available to each stack
106** layer without having to malloc. NBFS is short for Number of Bytes
107** For Strings.
108*/
109#define NBFS 32
110
111/*
112** A value for Cursor.cacheValid that means the cache is always invalid.
113*/
114#define CACHE_STALE 0
115
116/*
117** Internally, the vdbe manipulates nearly all SQL values as Mem
118** structures. Each Mem struct may cache multiple representations (string,
119** integer etc.) of the same value. A value (and therefore Mem structure)
120** has the following properties:
121**
122** Each value has a manifest type. The manifest type of the value stored
123** in a Mem struct is returned by the MemType(Mem*) macro. The type is
124** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or
125** SQLITE_BLOB.
126*/
127struct Mem {
128 union {
129 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */
130 FuncDef *pDef; /* Used only when flags==MEM_Agg */
131 } u;
132 double r; /* Real value */
133 char *z; /* String or BLOB value */
134 int n; /* Number of characters in string value, including '\0' */
135 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
136 u8 type; /* One of SQLITE_NULL, SQLITE_TEXT, SQLITE_INTEGER, etc */
137 u8 enc; /* SQLITE_UTF8, SQLITE_UTF16BE, SQLITE_UTF16LE */
138 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */
139 char zShort[NBFS]; /* Space for short strings */
140};
141typedef struct Mem Mem;
142
143/* One or more of the following flags are set to indicate the validOK
144** representations of the value stored in the Mem struct.
145**
146** If the MEM_Null flag is set, then the value is an SQL NULL value.
147** No other flags may be set in this case.
148**
149** If the MEM_Str flag is set then Mem.z points at a string representation.
150** Usually this is encoded in the same unicode encoding as the main
151** database (see below for exceptions). If the MEM_Term flag is also
152** set, then the string is nul terminated. The MEM_Int and MEM_Real
153** flags may coexist with the MEM_Str flag.
154**
155** Multiple of these values can appear in Mem.flags. But only one
156** at a time can appear in Mem.type.
157*/
158#define MEM_Null 0x0001 /* Value is NULL */
159#define MEM_Str 0x0002 /* Value is a string */
160#define MEM_Int 0x0004 /* Value is an integer */
161#define MEM_Real 0x0008 /* Value is a real number */
162#define MEM_Blob 0x0010 /* Value is a BLOB */
163
164/* Whenever Mem contains a valid string or blob representation, one of
165** the following flags must be set to determine the memory management
166** policy for Mem.z. The MEM_Term flag tells us whether or not the
167** string is \000 or \u0000 terminated
168*/
169#define MEM_Term 0x0020 /* String rep is nul terminated */
170#define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */
171#define MEM_Static 0x0080 /* Mem.z points to a static string */
172#define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */
173#define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */
174#define MEM_Agg 0x0400 /* Mem.z points to an agg function context */
175#define MEM_Zero 0x0800 /* Mem.i contains count of 0s appended to blob */
176
177#ifdef SQLITE_OMIT_INCRBLOB
178 #undef MEM_Zero
179 #define MEM_Zero 0x0000
180#endif
181
182
183/* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains
184** additional information about auxiliary information bound to arguments
185** of the function. This is used to implement the sqlite3_get_auxdata()
186** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data
187** that can be associated with a constant argument to a function. This
188** allows functions such as "regexp" to compile their constant regular
189** expression argument once and reused the compiled code for multiple
190** invocations.
191*/
192struct VdbeFunc {
193 FuncDef *pFunc; /* The definition of the function */
194 int nAux; /* Number of entries allocated for apAux[] */
195 struct AuxData {
196 void *pAux; /* Aux data for the i-th argument */
197 void (*xDelete)(void *); /* Destructor for the aux data */
198 } apAux[1]; /* One slot for each function argument */
199};
200typedef struct VdbeFunc VdbeFunc;
201
202/*
203** The "context" argument for a installable function. A pointer to an
204** instance of this structure is the first argument to the routines used
205** implement the SQL functions.
206**
207** There is a typedef for this structure in sqlite.h. So all routines,
208** even the public interface to SQLite, can use a pointer to this structure.
209** But this file is the only place where the internal details of this
210** structure are known.
211**
212** This structure is defined inside of vdbeInt.h because it uses substructures
213** (Mem) which are only defined there.
214*/
215struct sqlite3_context {
216 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */
217 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */
218 Mem s; /* The return value is stored here */
219 Mem *pMem; /* Memory cell used to store aggregate context */
220 u8 isError; /* Set to true for an error */
221 CollSeq *pColl; /* Collating sequence */
222};
223
224/*
225** A Set structure is used for quick testing to see if a value
226** is part of a small set. Sets are used to implement code like
227** this:
228** x.y IN ('hi','hoo','hum')
229*/
230typedef struct Set Set;
231struct Set {
232 Hash hash; /* A set is just a hash table */
233 HashElem *prev; /* Previously accessed hash elemen */
234};
235
236/*
237** A FifoPage structure holds a single page of valves. Pages are arranged
238** in a list.
239*/
240typedef struct FifoPage FifoPage;
241struct FifoPage {
242 int nSlot; /* Number of entries aSlot[] */
243 int iWrite; /* Push the next value into this entry in aSlot[] */
244 int iRead; /* Read the next value from this entry in aSlot[] */
245 FifoPage *pNext; /* Next page in the fifo */
246 i64 aSlot[1]; /* One or more slots for rowid values */
247};
248
249/*
250** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation
251** of that structure is private to this file.
252**
253** The Fifo structure describes the entire fifo.
254*/
255typedef struct Fifo Fifo;
256struct Fifo {
257 int nEntry; /* Total number of entries */
258 FifoPage *pFirst; /* First page on the list */
259 FifoPage *pLast; /* Last page on the list */
260};
261
262/*
263** A Context stores the last insert rowid, the last statement change count,
264** and the current statement change count (i.e. changes since last statement).
265** The current keylist is also stored in the context.
266** Elements of Context structure type make up the ContextStack, which is
267** updated by the ContextPush and ContextPop opcodes (used by triggers).
268** The context is pushed before executing a trigger a popped when the
269** trigger finishes.
270*/
271typedef struct Context Context;
272struct Context {
273 i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */
274 int nChange; /* Statement changes (Vdbe.nChanges) */
275 Fifo sFifo; /* Records that will participate in a DELETE or UPDATE */
276};
277
278/*
279** An instance of the virtual machine. This structure contains the complete
280** state of the virtual machine.
281**
282** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile()
283** is really a pointer to an instance of this structure.
284**
285** The Vdbe.inVtabMethod variable is set to non-zero for the duration of
286** any virtual table method invocations made by the vdbe program. It is
287** set to 2 for xDestroy method calls and 1 for all other methods. This
288** variable is used for two purposes: to allow xDestroy methods to execute
289** "DROP TABLE" statements and to prevent some nasty side effects of
290** malloc failure when SQLite is invoked recursively by a virtual table
291** method function.
292*/
293struct Vdbe {
294 sqlite3 *db; /* The whole database */
295 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
296 int nOp; /* Number of instructions in the program */
297 int nOpAlloc; /* Number of slots allocated for aOp[] */
298 Op *aOp; /* Space to hold the virtual machine's program */
299 int nLabel; /* Number of labels used */
300 int nLabelAlloc; /* Number of slots allocated in aLabel[] */
301 int *aLabel; /* Space to hold the labels */
302 Mem *aStack; /* The operand stack, except string values */
303 Mem *pTos; /* Top entry in the operand stack */
304 Mem **apArg; /* Arguments to currently executing user function */
305 Mem *aColName; /* Column names to return */
306 int nCursor; /* Number of slots in apCsr[] */
307 Cursor **apCsr; /* One element of this array for each open cursor */
308 int nVar; /* Number of entries in aVar[] */
309 Mem *aVar; /* Values for the OP_Variable opcode. */
310 char **azVar; /* Name of variables */
311 int okVar; /* True if azVar[] has been initialized */
312 int magic; /* Magic number for sanity checking */
313 int nMem; /* Number of memory locations currently allocated */
314 Mem *aMem; /* The memory locations */
315 int nCallback; /* Number of callbacks invoked so far */
316 int cacheCtr; /* Cursor row cache generation counter */
317 Fifo sFifo; /* A list of ROWIDs */
318 int contextStackTop; /* Index of top element in the context stack */
319 int contextStackDepth; /* The size of the "context" stack */
320 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/
321 int pc; /* The program counter */
322 int rc; /* Value to return */
323 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */
324 int errorAction; /* Recovery action to do in case of an error */
325 int inTempTrans; /* True if temp database is transactioned */
326 int returnStack[100]; /* Return address stack for OP_Gosub & OP_Return */
327 int returnDepth; /* Next unused element in returnStack[] */
328 int nResColumn; /* Number of columns in one row of the result set */
329 char **azResColumn; /* Values for one row of result */
330 int popStack; /* Pop the stack this much on entry to VdbeExec() */
331 char *zErrMsg; /* Error message written here */
332 u8 resOnStack; /* True if there are result values on the stack */
333 u8 explain; /* True if EXPLAIN present on SQL command */
334 u8 changeCntOn; /* True to update the change-counter */
335 u8 aborted; /* True if ROLLBACK in another VM causes an abort */
336 u8 expired; /* True if the VM needs to be recompiled */
337 u8 minWriteFileFormat; /* Minimum file format for writable database files */
338 u8 inVtabMethod; /* See comments above */
339 int nChange; /* Number of db changes made since last reset */
340 i64 startTime; /* Time when query started - used for profiling */
341 int nSql; /* Number of bytes in zSql */
342 char *zSql; /* Text of the SQL statement that generated this */
343#ifdef SQLITE_DEBUG
344 FILE *trace; /* Write an execution trace here, if not NULL */
345#endif
346#ifdef SQLITE_SSE
347 int fetchId; /* Statement number used by sqlite3_fetch_statement */
348 int lru; /* Counter used for LRU cache replacement */
349#endif
350};
351
352/*
353** The following are allowed values for Vdbe.magic
354*/
355#define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */
356#define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */
357#define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */
358#define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */
359
360/*
361** Function prototypes
362*/
363void sqlite3VdbeFreeCursor(Vdbe *, Cursor*);
364void sqliteVdbePopStack(Vdbe*,int);
365int sqlite3VdbeCursorMoveto(Cursor*);
366#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
367void sqlite3VdbePrintOp(FILE*, int, Op*);
368#endif
369int sqlite3VdbeSerialTypeLen(u32);
370u32 sqlite3VdbeSerialType(Mem*, int);
371int sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int);
372int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
373void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
374
375int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
376int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*);
377int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
378int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
379int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*);
380int sqlite3VdbeIdxRowidLen(const u8*);
381int sqlite3VdbeExec(Vdbe*);
382int sqlite3VdbeList(Vdbe*);
383int sqlite3VdbeHalt(Vdbe*);
384int sqlite3VdbeChangeEncoding(Mem *, int);
385int sqlite3VdbeMemTooBig(Mem*);
386int sqlite3VdbeMemCopy(Mem*, const Mem*);
387void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
388int sqlite3VdbeMemMove(Mem*, Mem*);
389int sqlite3VdbeMemNulTerminate(Mem*);
390int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
391void sqlite3VdbeMemSetInt64(Mem*, i64);
392void sqlite3VdbeMemSetDouble(Mem*, double);
393void sqlite3VdbeMemSetNull(Mem*);
394void sqlite3VdbeMemSetZeroBlob(Mem*,int);
395int sqlite3VdbeMemMakeWriteable(Mem*);
396int sqlite3VdbeMemDynamicify(Mem*);
397int sqlite3VdbeMemStringify(Mem*, int);
398i64 sqlite3VdbeIntValue(Mem*);
399int sqlite3VdbeMemIntegerify(Mem*);
400double sqlite3VdbeRealValue(Mem*);
401void sqlite3VdbeIntegerAffinity(Mem*);
402int sqlite3VdbeMemRealify(Mem*);
403int sqlite3VdbeMemNumerify(Mem*);
404int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
405void sqlite3VdbeMemRelease(Mem *p);
406int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
407#ifndef NDEBUG
408 void sqlite3VdbeMemSanity(Mem*);
409 int sqlite3VdbeOpcodeNoPush(u8);
410#endif
411int sqlite3VdbeMemTranslate(Mem*, u8);
412#ifdef SQLITE_DEBUG
413 void sqlite3VdbePrintSql(Vdbe*);
414 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
415#endif
416int sqlite3VdbeMemHandleBom(Mem *pMem);
417void sqlite3VdbeFifoInit(Fifo*);
418int sqlite3VdbeFifoPush(Fifo*, i64);
419int sqlite3VdbeFifoPop(Fifo*, i64*);
420void sqlite3VdbeFifoClear(Fifo*);
421
422#ifndef SQLITE_OMIT_INCRBLOB
423 int sqlite3VdbeMemExpandBlob(Mem *);
424#else
425 #define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
426#endif
427
428#endif /* !defined(_VDBEINT_H_) */

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