|
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 int iDb; /* Index of cursor database in db->aDb[] (or -1) */ |
|
64 i64 lastRowid; /* Last rowid from a Next or NextIdx operation */ |
|
65 i64 nextRowid; /* Next rowid returned by OP_NewRowid */ |
|
66 Bool zeroed; /* True if zeroed out and ready for reuse */ |
|
67 Bool rowidIsValid; /* True if lastRowid is valid */ |
|
68 Bool atFirst; /* True if pointing to first entry */ |
|
69 Bool useRandomRowid; /* Generate new record numbers semi-randomly */ |
|
70 Bool nullRow; /* True if pointing to a row with no data */ |
|
71 Bool nextRowidValid; /* True if the nextRowid field is valid */ |
|
72 Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */ |
|
73 Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */ |
|
74 Bool isTable; /* True if a table requiring integer keys */ |
|
75 Bool isIndex; /* True if an index containing keys only - no data */ |
|
76 u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */ |
|
77 i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */ |
|
78 Btree *pBt; /* Separate file holding temporary table */ |
|
79 int nData; /* Number of bytes in pData */ |
|
80 char *pData; /* Data for a NEW or OLD pseudo-table */ |
|
81 i64 iKey; /* Key for the NEW or OLD pseudo-table row */ |
|
82 u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */ |
|
83 KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */ |
|
84 int nField; /* Number of fields in the header */ |
|
85 i64 seqCount; /* Sequence counter */ |
|
86 sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */ |
|
87 const sqlite3_module *pModule; /* Module for cursor pVtabCursor */ |
|
88 |
|
89 /* Cached information about the header for the data record that the |
|
90 ** cursor is currently pointing to. Only valid if cacheValid is true. |
|
91 ** aRow might point to (ephemeral) data for the current row, or it might |
|
92 ** be NULL. |
|
93 */ |
|
94 int cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */ |
|
95 int payloadSize; /* Total number of bytes in the record */ |
|
96 u32 *aType; /* Type values for all entries in the record */ |
|
97 u32 *aOffset; /* Cached offsets to the start of each columns data */ |
|
98 u8 *aRow; /* Data for the current row, if all on one page */ |
|
99 }; |
|
100 typedef struct Cursor Cursor; |
|
101 |
|
102 /* |
|
103 ** Number of bytes of string storage space available to each stack |
|
104 ** layer without having to malloc. NBFS is short for Number of Bytes |
|
105 ** For Strings. |
|
106 */ |
|
107 #define NBFS 32 |
|
108 |
|
109 /* |
|
110 ** A value for Cursor.cacheValid that means the cache is always invalid. |
|
111 */ |
|
112 #define CACHE_STALE 0 |
|
113 |
|
114 /* |
|
115 ** Internally, the vdbe manipulates nearly all SQL values as Mem |
|
116 ** structures. Each Mem struct may cache multiple representations (string, |
|
117 ** integer etc.) of the same value. A value (and therefore Mem structure) |
|
118 ** has the following properties: |
|
119 ** |
|
120 ** Each value has a manifest type. The manifest type of the value stored |
|
121 ** in a Mem struct is returned by the MemType(Mem*) macro. The type is |
|
122 ** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or |
|
123 ** SQLITE_BLOB. |
|
124 */ |
|
125 struct Mem { |
|
126 i64 i; /* Integer value. Or FuncDef* when flags==MEM_Agg */ |
|
127 double r; /* Real value */ |
|
128 char *z; /* String or BLOB value */ |
|
129 int n; /* Number of characters in string value, including '\0' */ |
|
130 u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */ |
|
131 u8 type; /* One of MEM_Null, MEM_Str, etc. */ |
|
132 u8 enc; /* TEXT_Utf8, TEXT_Utf16le, or TEXT_Utf16be */ |
|
133 void (*xDel)(void *); /* If not null, call this function to delete Mem.z */ |
|
134 char zShort[NBFS]; /* Space for short strings */ |
|
135 }; |
|
136 typedef struct Mem Mem; |
|
137 |
|
138 /* One or more of the following flags are set to indicate the validOK |
|
139 ** representations of the value stored in the Mem struct. |
|
140 ** |
|
141 ** If the MEM_Null flag is set, then the value is an SQL NULL value. |
|
142 ** No other flags may be set in this case. |
|
143 ** |
|
144 ** If the MEM_Str flag is set then Mem.z points at a string representation. |
|
145 ** Usually this is encoded in the same unicode encoding as the main |
|
146 ** database (see below for exceptions). If the MEM_Term flag is also |
|
147 ** set, then the string is nul terminated. The MEM_Int and MEM_Real |
|
148 ** flags may coexist with the MEM_Str flag. |
|
149 ** |
|
150 ** Multiple of these values can appear in Mem.flags. But only one |
|
151 ** at a time can appear in Mem.type. |
|
152 */ |
|
153 #define MEM_Null 0x0001 /* Value is NULL */ |
|
154 #define MEM_Str 0x0002 /* Value is a string */ |
|
155 #define MEM_Int 0x0004 /* Value is an integer */ |
|
156 #define MEM_Real 0x0008 /* Value is a real number */ |
|
157 #define MEM_Blob 0x0010 /* Value is a BLOB */ |
|
158 |
|
159 /* Whenever Mem contains a valid string or blob representation, one of |
|
160 ** the following flags must be set to determine the memory management |
|
161 ** policy for Mem.z. The MEM_Term flag tells us whether or not the |
|
162 ** string is \000 or \u0000 terminated |
|
163 */ |
|
164 #define MEM_Term 0x0020 /* String rep is nul terminated */ |
|
165 #define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */ |
|
166 #define MEM_Static 0x0080 /* Mem.z points to a static string */ |
|
167 #define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */ |
|
168 #define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */ |
|
169 #define MEM_Agg 0x0400 /* Mem.z points to an agg function context */ |
|
170 |
|
171 |
|
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 |
|
179 ** invocations. |
|
180 */ |
|
181 struct VdbeFunc { |
|
182 FuncDef *pFunc; /* The definition of the function */ |
|
183 int nAux; /* Number of entries allocated for apAux[] */ |
|
184 struct AuxData { |
|
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 */ |
|
188 }; |
|
189 typedef struct VdbeFunc VdbeFunc; |
|
190 |
|
191 /* |
|
192 ** The "context" argument for a installable function. A pointer to an |
|
193 ** instance of this structure is the first argument to the routines used |
|
194 ** implement the SQL functions. |
|
195 ** |
|
196 ** There is a typedef for this structure in sqlite.h. So all routines, |
|
197 ** even the public interface to SQLite, can use a pointer to this structure. |
|
198 ** But this file is the only place where the internal details of this |
|
199 ** structure are known. |
|
200 ** |
|
201 ** This structure is defined inside of vdbeInt.h because it uses substructures |
|
202 ** (Mem) which are only defined there. |
|
203 */ |
|
204 struct sqlite3_context { |
|
205 FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */ |
|
206 VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */ |
|
207 Mem s; /* The return value is stored here */ |
|
208 Mem *pMem; /* Memory cell used to store aggregate context */ |
|
209 u8 isError; /* Set to true for an error */ |
|
210 CollSeq *pColl; /* Collating sequence */ |
|
211 }; |
|
212 |
|
213 /* |
|
214 ** A Set structure is used for quick testing to see if a value |
|
215 ** is part of a small set. Sets are used to implement code like |
|
216 ** this: |
|
217 ** x.y IN ('hi','hoo','hum') |
|
218 */ |
|
219 typedef struct Set Set; |
|
220 struct Set { |
|
221 Hash hash; /* A set is just a hash table */ |
|
222 HashElem *prev; /* Previously accessed hash elemen */ |
|
223 }; |
|
224 |
|
225 /* |
|
226 ** A FifoPage structure holds a single page of valves. Pages are arranged |
|
227 ** in a list. |
|
228 */ |
|
229 typedef struct FifoPage FifoPage; |
|
230 struct FifoPage { |
|
231 int nSlot; /* Number of entries aSlot[] */ |
|
232 int iWrite; /* Push the next value into this entry in aSlot[] */ |
|
233 int iRead; /* Read the next value from this entry in aSlot[] */ |
|
234 FifoPage *pNext; /* Next page in the fifo */ |
|
235 i64 aSlot[1]; /* One or more slots for rowid values */ |
|
236 }; |
|
237 |
|
238 /* |
|
239 ** The Fifo structure is typedef-ed in vdbeInt.h. But the implementation |
|
240 ** of that structure is private to this file. |
|
241 ** |
|
242 ** The Fifo structure describes the entire fifo. |
|
243 */ |
|
244 typedef struct Fifo Fifo; |
|
245 struct Fifo { |
|
246 int nEntry; /* Total number of entries */ |
|
247 FifoPage *pFirst; /* First page on the list */ |
|
248 FifoPage *pLast; /* Last page on the list */ |
|
249 }; |
|
250 |
|
251 /* |
|
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 |
|
258 ** trigger finishes. |
|
259 */ |
|
260 typedef struct Context Context; |
|
261 struct 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 */ |
|
265 }; |
|
266 |
|
267 /* |
|
268 ** An instance of the virtual machine. This structure contains the complete |
|
269 ** state of the virtual machine. |
|
270 ** |
|
271 ** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile() |
|
272 ** is really a pointer to an instance of this structure. |
|
273 ** |
|
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 |
|
280 ** method function. |
|
281 */ |
|
282 struct Vdbe { |
|
283 sqlite3 *db; /* The whole database */ |
|
284 Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */ |
|
285 FILE *trace; /* Write an execution trace here, if not NULL */ |
|
286 int nOp; /* Number of instructions in the program */ |
|
287 int nOpAlloc; /* Number of slots allocated for aOp[] */ |
|
288 Op *aOp; /* Space to hold the virtual machine's program */ |
|
289 int nLabel; /* Number of labels used */ |
|
290 int nLabelAlloc; /* Number of slots allocated in aLabel[] */ |
|
291 int *aLabel; /* Space to hold the labels */ |
|
292 Mem *aStack; /* The operand stack, except string values */ |
|
293 Mem *pTos; /* Top entry in the operand stack */ |
|
294 Mem **apArg; /* Arguments to currently executing user function */ |
|
295 Mem *aColName; /* Column names to return */ |
|
296 int nCursor; /* Number of slots in apCsr[] */ |
|
297 Cursor **apCsr; /* One element of this array for each open cursor */ |
|
298 int nVar; /* Number of entries in aVar[] */ |
|
299 Mem *aVar; /* Values for the OP_Variable opcode. */ |
|
300 char **azVar; /* Name of variables */ |
|
301 int okVar; /* True if azVar[] has been initialized */ |
|
302 int magic; /* Magic number for sanity checking */ |
|
303 int nMem; /* Number of memory locations currently allocated */ |
|
304 Mem *aMem; /* The memory locations */ |
|
305 int nCallback; /* Number of callbacks invoked so far */ |
|
306 int cacheCtr; /* Cursor row cache generation counter */ |
|
307 Fifo sFifo; /* A list of ROWIDs */ |
|
308 int contextStackTop; /* Index of top element in the context stack */ |
|
309 int contextStackDepth; /* The size of the "context" stack */ |
|
310 Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/ |
|
311 int pc; /* The program counter */ |
|
312 int rc; /* Value to return */ |
|
313 unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */ |
|
314 int errorAction; /* Recovery action to do in case of an error */ |
|
315 int inTempTrans; /* True if temp database is transactioned */ |
|
316 int returnStack[100]; /* Return address stack for OP_Gosub & OP_Return */ |
|
317 int returnDepth; /* Next unused element in returnStack[] */ |
|
318 int nResColumn; /* Number of columns in one row of the result set */ |
|
319 char **azResColumn; /* Values for one row of result */ |
|
320 int popStack; /* Pop the stack this much on entry to VdbeExec() */ |
|
321 char *zErrMsg; /* Error message written here */ |
|
322 u8 resOnStack; /* True if there are result values on the stack */ |
|
323 u8 explain; /* True if EXPLAIN present on SQL command */ |
|
324 u8 changeCntOn; /* True to update the change-counter */ |
|
325 u8 aborted; /* True if ROLLBACK in another VM causes an abort */ |
|
326 u8 expired; /* True if the VM needs to be recompiled */ |
|
327 u8 minWriteFileFormat; /* Minimum file format for writable database files */ |
|
328 u8 inVtabMethod; /* See comments above */ |
|
329 int nChange; /* Number of db changes made since last reset */ |
|
330 i64 startTime; /* Time when query started - used for profiling */ |
|
331 #ifdef SQLITE_SSE |
|
332 int fetchId; /* Statement number used by sqlite3_fetch_statement */ |
|
333 int lru; /* Counter used for LRU cache replacement */ |
|
334 #endif |
|
335 }; |
|
336 |
|
337 /* |
|
338 ** The following are allowed values for Vdbe.magic |
|
339 */ |
|
340 #define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */ |
|
341 #define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */ |
|
342 #define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */ |
|
343 #define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */ |
|
344 |
|
345 /* |
|
346 ** Function prototypes |
|
347 */ |
|
348 void sqlite3VdbeFreeCursor(Vdbe *, Cursor*); |
|
349 void sqliteVdbePopStack(Vdbe*,int); |
|
350 int sqlite3VdbeCursorMoveto(Cursor*); |
|
351 #if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE) |
|
352 void sqlite3VdbePrintOp(FILE*, int, Op*); |
|
353 #endif |
|
354 #ifdef SQLITE_DEBUG |
|
355 void sqlite3VdbePrintSql(Vdbe*); |
|
356 #endif |
|
357 int sqlite3VdbeSerialTypeLen(u32); |
|
358 u32 sqlite3VdbeSerialType(Mem*, int); |
|
359 int sqlite3VdbeSerialPut(unsigned char*, Mem*, int); |
|
360 int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*); |
|
361 void sqlite3VdbeDeleteAuxData(VdbeFunc*, int); |
|
362 |
|
363 int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *); |
|
364 int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*); |
|
365 int sqlite3VdbeIdxRowid(BtCursor *, i64 *); |
|
366 int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*); |
|
367 int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*); |
|
368 int sqlite3VdbeIdxRowidLen(const u8*); |
|
369 int sqlite3VdbeExec(Vdbe*); |
|
370 int sqlite3VdbeList(Vdbe*); |
|
371 int sqlite3VdbeHalt(Vdbe*); |
|
372 int sqlite3VdbeChangeEncoding(Mem *, int); |
|
373 int sqlite3VdbeMemCopy(Mem*, const Mem*); |
|
374 void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int); |
|
375 int sqlite3VdbeMemMove(Mem*, Mem*); |
|
376 int sqlite3VdbeMemNulTerminate(Mem*); |
|
377 int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*)); |
|
378 void sqlite3VdbeMemSetInt64(Mem*, i64); |
|
379 void sqlite3VdbeMemSetDouble(Mem*, double); |
|
380 void sqlite3VdbeMemSetNull(Mem*); |
|
381 int sqlite3VdbeMemMakeWriteable(Mem*); |
|
382 int sqlite3VdbeMemDynamicify(Mem*); |
|
383 int sqlite3VdbeMemStringify(Mem*, int); |
|
384 i64 sqlite3VdbeIntValue(Mem*); |
|
385 int sqlite3VdbeMemIntegerify(Mem*); |
|
386 double sqlite3VdbeRealValue(Mem*); |
|
387 void sqlite3VdbeIntegerAffinity(Mem*); |
|
388 int sqlite3VdbeMemRealify(Mem*); |
|
389 int sqlite3VdbeMemNumerify(Mem*); |
|
390 int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*); |
|
391 void sqlite3VdbeMemRelease(Mem *p); |
|
392 int sqlite3VdbeMemFinalize(Mem*, FuncDef*); |
|
393 #ifndef NDEBUG |
|
394 void sqlite3VdbeMemSanity(Mem*); |
|
395 int sqlite3VdbeOpcodeNoPush(u8); |
|
396 #endif |
|
397 int sqlite3VdbeMemTranslate(Mem*, u8); |
|
398 void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf); |
|
399 int sqlite3VdbeMemHandleBom(Mem *pMem); |
|
400 void sqlite3VdbeFifoInit(Fifo*); |
|
401 int sqlite3VdbeFifoPush(Fifo*, i64); |
|
402 int sqlite3VdbeFifoPop(Fifo*, i64*); |
|
403 void sqlite3VdbeFifoClear(Fifo*); |