/ Check-in [10bba8d0]
Login

Many hyperlinks are disabled.
Use anonymous login to enable hyperlinks.

Overview
Comment:Add a prototype for an extension that sits in between the SQLite native code virtual table interface and a CLR IDisposable object.
Downloads: Tarball | ZIP archive | SQL archive
Timelines: family | ancestors | descendants | both | disposable-vtable
Files: files | file ages | folders
SHA1: 10bba8d0821159a45c6a0d6c3cef897cb4d4e9a6
User & Date: drh 2013-06-13 00:32:29
Context
2013-06-20
00:20
Integration adjustments for the vtshim module. check-in: bf2e28dd user: mistachkin tags: disposable-vtable
2013-06-13
00:32
Add a prototype for an extension that sits in between the SQLite native code virtual table interface and a CLR IDisposable object. check-in: 10bba8d0 user: drh tags: disposable-vtable
2013-06-12
20:18
Activate the one-pass optimization. Update comments, especially the descriptions of the various objects. check-in: e120c558 user: drh tags: nextgen-query-plan-exp
Changes
Hide Diffs Unified Diffs Ignore Whitespace Patch

Added ext/misc/vtshim.c.









































































































































































































































































































































































































































































































































































































































































































































































































































































>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
/*
** 2013-06-12
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
**
** A shim that sits between the SQLite virtual table interface and
** managed memory of .NET
*/
#include "sqlite3ext.h"
SQLITE_EXTENSION_INIT1
#include <assert.h>
#include <string.h>

#ifndef SQLITE_OMIT_VIRTUALTABLE

/* Forward references */
typedef struct vtshim_aux vtshim_aux;
typedef struct vtshim_vtab vtshim_vtab;
typedef struct vtshim_cursor vtshim_cursor;


/* The vtshim_aux argument is the auxiliary parameter that is passed
** into sqlite3_create_module_v2().
*/
struct vtshim_aux {
  void *pChildAux;              /* pAux for child virtual tables */
  void (*xChildDestroy)(void*); /* Destructor for pChildAux */
  const sqlite3_module *pMod;   /* Methods for child virtual tables */
  sqlite3 *db;                  /* The database to which we are attached */
  const char *zName;            /* Name of the module */
  int bDisposed;                /* True if disposed */
  vtshim_vtab *pAllVtab;        /* List of all vtshim_vtab objects */
  sqlite3_module sSelf;         /* Methods used by this shim */
};

/* A vtshim virtual table object */
struct vtshim_vtab {
  sqlite3_vtab base;       /* Base class - must be first */
  sqlite3_vtab *pChild;    /* Child virtual table */
  vtshim_aux *pAux;        /* Pointer to vtshim_aux object */
  vtshim_cursor *pAllCur;  /* List of all cursors */
  vtshim_vtab **ppPrev;    /* Previous on list */
  vtshim_vtab *pNext;      /* Next on list */
};

/* A vtshim cursor object */
struct vtshim_cursor {
  sqlite3_vtab_cursor base;    /* Base class - must be first */
  sqlite3_vtab_cursor *pChild; /* Cursor generated by the managed subclass */
  vtshim_cursor **ppPrev;      /* Previous on list of all cursors */
  vtshim_cursor *pNext;        /* Next on list of all cursors */
};

/* Methods for the vtshim module */
static int vtshimCreate(
  sqlite3 *db,
  void *pPAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  vtshim_aux *pAux = (vtshim_aux*)pPAux;
  vtshim_vtab *pNew;
  int rc; 

  assert( db==pAux->db );
  pNew = sqlite3_malloc( sizeof(*pNew) );
  *ppVtab = (sqlite3_vtab*)pNew;
  if( pNew==0 ) return SQLITE_NOMEM;
  memset(pNew, 0, sizeof(*pNew));
  rc = pAux->pMod->xCreate(db, pAux->pChildAux, argc, argv,
                           &pNew->pChild, pzErr);
  if( rc ){
    sqlite3_free(pNew);
    *ppVtab = 0;
  }
  pNew->ppPrev = &pAux->pAllVtab;
  pNew->pNext = pAux->pAllVtab;
  if( pAux->pAllVtab ) pAux->pAllVtab->ppPrev = &pNew->pNext;
  pAux->pAllVtab = pNew;
  return rc;
}

static int vtshimConnect(
  sqlite3 *db,
  void *pPAux,
  int argc, const char *const*argv,
  sqlite3_vtab **ppVtab,
  char **pzErr
){
  vtshim_aux *pAux = (vtshim_aux*)pPAux;
  vtshim_vtab *pNew;
  int rc; 

  assert( db==pAux->db );
  pNew = sqlite3_malloc( sizeof(*pNew) );
  *ppVtab = (sqlite3_vtab*)pNew;
  if( pNew==0 ) return SQLITE_NOMEM;
  memset(pNew, 0, sizeof(*pNew));
  rc = pAux->pMod->xConnect(db, pAux->pChildAux, argc, argv,
                            &pNew->pChild, pzErr);
  if( rc ){
    sqlite3_free(pNew);
    *ppVtab = 0;
  }
  pNew->ppPrev = &pAux->pAllVtab;
  pNew->pNext = pAux->pAllVtab;
  if( pAux->pAllVtab ) pAux->pAllVtab->ppPrev = &pNew->pNext;
  pAux->pAllVtab = pNew;
  return rc;
}

static int vtshimBestIndex(
  sqlite3_vtab *pBase,
  sqlite3_index_info *pIdxInfo
){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xBestIndex(pVtab->pChild, pIdxInfo);
}


static int vtshimDisconnect(sqlite3_vtab *pBase){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  int rc = SQLITE_OK;
  if( !pAux->bDisposed ){
    rc = pAux->pMod->xDisconnect(pVtab->pChild);
  }
  if( pVtab->pNext ) pVtab->pNext->ppPrev = pVtab->ppPrev;
  *pVtab->ppPrev = pVtab->pNext;
  sqlite3_free(pVtab);
  return rc;
}

static int vtshimDestroy(sqlite3_vtab *pBase){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  int rc = SQLITE_OK;
  if( !pAux->bDisposed ){
    rc = pAux->pMod->xDestroy(pVtab->pChild);
  }
  if( pVtab->pNext ) pVtab->pNext->ppPrev = pVtab->ppPrev;
  *pVtab->ppPrev = pVtab->pNext;
  sqlite3_free(pVtab);
  return rc;
}

static int vtshimOpen(sqlite3_vtab *pBase, sqlite3_vtab_cursor **ppCursor){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  vtshim_cursor *pCur;
  int rc;
  *ppCursor = 0;
  if( pAux->bDisposed )  return SQLITE_ERROR;
  pCur = sqlite3_malloc( sizeof(*pCur) );
  if( pCur==0 ) return SQLITE_NOMEM;
  memset(pCur, 0, sizeof(*pCur));
  rc = pAux->pMod->xOpen(pVtab->pChild, &pCur->pChild);
  if( rc ){
    sqlite3_free(pCur);
    return rc;
  }
  pCur->pChild->pVtab = pVtab->pChild;
  *ppCursor = &pCur->base;
  pCur->ppPrev = &pVtab->pAllCur;
  if( pVtab->pAllCur ) pVtab->pAllCur->ppPrev = &pCur->pNext;
  pCur->pNext = pVtab->pAllCur;
  pVtab->pAllCur = pCur;
  return SQLITE_OK;
}

static int vtshimClose(sqlite3_vtab_cursor *pX){
  vtshim_cursor *pCur = (vtshim_cursor*)pX;
  vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
  vtshim_aux *pAux = pVtab->pAux;
  int rc = SQLITE_OK;
  if( !pAux->bDisposed ){
    rc = pAux->pMod->xClose(pCur->pChild);
  }
  if( pCur->pNext ) pCur->pNext->ppPrev = pCur->ppPrev;
  *pCur->ppPrev = pCur->pNext;
  sqlite3_free(pCur);
  return rc;
}

static int vtshimFilter(
  sqlite3_vtab_cursor *pX,
  int idxNum, const char *idxStr,
  int argc, sqlite3_value **argv
){
  vtshim_cursor *pCur = (vtshim_cursor*)pX;
  vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xFilter(pCur->pChild, idxNum, idxStr, argc, argv);
}

static int vtshimNext(sqlite3_vtab_cursor *pX){
  vtshim_cursor *pCur = (vtshim_cursor*)pX;
  vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xNext(pCur->pChild);
}

static int vtshimEof(sqlite3_vtab_cursor *pX){
  vtshim_cursor *pCur = (vtshim_cursor*)pX;
  vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xEof(pCur->pChild);
}

static int vtshimColumn(sqlite3_vtab_cursor *pX, sqlite3_context *ctx, int i){
  vtshim_cursor *pCur = (vtshim_cursor*)pX;
  vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xColumn(pCur->pChild, ctx, i);
}

static int vtshimRowid(sqlite3_vtab_cursor *pX, sqlite3_int64 *pRowid){
  vtshim_cursor *pCur = (vtshim_cursor*)pX;
  vtshim_vtab *pVtab = (vtshim_vtab*)pCur->base.pVtab;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xRowid(pCur->pChild, pRowid);
}

static int vtshimUpdate(
  sqlite3_vtab *pBase,
  int argc,
  sqlite3_value **argv,
  sqlite3_int64 *pRowid
){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xUpdate(pVtab->pChild, argc, argv, pRowid);
}

static int vtshimBegin(sqlite3_vtab *pBase){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xBegin(pVtab->pChild);
}

static int vtshimSync(sqlite3_vtab *pBase){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xSync(pVtab->pChild);
}

static int vtshimCommit(sqlite3_vtab *pBase){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xCommit(pVtab->pChild);
}

static int vtshimRollback(sqlite3_vtab *pBase){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xRollback(pVtab->pChild);
}

static int vtshimFindFunction(
  sqlite3_vtab *pBase,
  int nArg,
  const char *zName,
  void (**pxFunc)(sqlite3_context*,int,sqlite3_value**),
  void **ppArg
){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xFindFunction(pVtab->pChild, nArg, zName, pxFunc, ppArg);
}

static int vtshimRename(sqlite3_vtab *pBase, const char *zNewName){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xRename(pVtab->pChild, zNewName);
}

static int vtshimSavepoint(sqlite3_vtab *pBase, int n){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xSavepoint(pVtab->pChild, n);
}

static int vtshimRelease(sqlite3_vtab *pBase, int n){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xRelease(pVtab->pChild, n);
}

static int vtshimRollbackTo(sqlite3_vtab *pBase, int n){
  vtshim_vtab *pVtab = (vtshim_vtab*)pBase;
  vtshim_aux *pAux = pVtab->pAux;
  if( pAux->bDisposed ) return SQLITE_ERROR;
  return pAux->pMod->xRollbackTo(pVtab->pChild, n);
}

/* The destructor function for a disposible module */
static void vtshimAuxDestructor(void *pXAux){
  vtshim_aux *pAux = (vtshim_aux*)pXAux;
  assert( pAux->pAllVtab==0 );
  if( !pAux->bDisposed && pAux->xChildDestroy ){
    pAux->xChildDestroy(pAux->pChildAux);
  }
  sqlite3_free(pAux);
}

#ifdef _WIN32
__declspec(dllexport)
#endif
void *sqlite3_create_disposable_module(
  sqlite3 *db,               /* SQLite connection to register module with */
  const char *zName,         /* Name of the module */
  const sqlite3_module *p,   /* Methods for the module */
  void *pClientData,         /* Client data for xCreate/xConnect */
  void(*xDestroy)(void*)     /* Module destructor function */
){
  vtshim_aux *pAux;
  int rc;
  pAux = sqlite3_malloc( sizeof(*pAux) );
  if( pAux==0 ){
    if( xDestroy ) xDestroy(pClientData);
    return 0;
  }
  pAux->pChildAux = pClientData;
  pAux->xChildDestroy = xDestroy;
  pAux->pMod = p;
  pAux->db = db;
  pAux->zName = zName;
  pAux->bDisposed = 0;
  pAux->pAllVtab = 0;
  pAux->sSelf.iVersion = p->iVersion<=1 ? p->iVersion : 1;
  pAux->sSelf.xCreate = p->xCreate ? vtshimCreate : 0;
  pAux->sSelf.xConnect = p->xConnect ? vtshimConnect : 0;
  pAux->sSelf.xBestIndex = p->xBestIndex ? vtshimBestIndex : 0;
  pAux->sSelf.xDisconnect = p->xDisconnect ? vtshimDisconnect : 0;
  pAux->sSelf.xDestroy = p->xDestroy ? vtshimDestroy : 0;
  pAux->sSelf.xOpen = p->xOpen ? vtshimOpen : 0;
  pAux->sSelf.xClose = p->xClose ? vtshimClose : 0;
  pAux->sSelf.xFilter = p->xFilter ? vtshimFilter : 0;
  pAux->sSelf.xNext = p->xNext ? vtshimNext : 0;
  pAux->sSelf.xEof = p->xEof ? vtshimEof : 0;
  pAux->sSelf.xColumn = p->xColumn ? vtshimColumn : 0;
  pAux->sSelf.xRowid = p->xRowid ? vtshimRowid : 0;
  pAux->sSelf.xUpdate = p->xUpdate ? vtshimUpdate : 0;
  pAux->sSelf.xBegin = p->xBegin ? vtshimBegin : 0;
  pAux->sSelf.xSync = p->xSync ? vtshimSync : 0;
  pAux->sSelf.xCommit = p->xCommit ? vtshimCommit : 0;
  pAux->sSelf.xRollback = p->xRollback ? vtshimRollback : 0;
  pAux->sSelf.xFindFunction = p->xFindFunction ? vtshimFindFunction : 0;
  pAux->sSelf.xRename = p->xRename ? vtshimRename : 0;
  if( p->iVersion>=1 ){
    pAux->sSelf.xSavepoint = p->xSavepoint ? vtshimSavepoint : 0;
    pAux->sSelf.xRelease = p->xRelease ? vtshimRelease : 0;
    pAux->sSelf.xRollbackTo = p->xRollbackTo ? vtshimRollbackTo : 0;
  }else{
    pAux->sSelf.xSavepoint = 0;
    pAux->sSelf.xRelease = 0;
    pAux->sSelf.xRollbackTo = 0;
  }
  rc = sqlite3_create_module_v2(db, zName, &pAux->sSelf,
                                pAux, vtshimAuxDestructor);
  return rc==SQLITE_OK ? (void*)pAux : 0;
}

#ifdef _WIN32
__declspec(dllexport)
#endif
void sqlite3_dispose_module(void *pX){
  vtshim_aux *pAux = (vtshim_aux*)pX;
  if( !pAux->bDisposed ){
    vtshim_vtab *pVtab;
    vtshim_cursor *pCur;
    for(pVtab=pAux->pAllVtab; pVtab; pVtab=pVtab->pNext){
      for(pCur=pVtab->pAllCur; pCur; pCur=pCur->pNext){
        pAux->pMod->xClose(pCur->pChild);
      }
      pAux->pMod->xDisconnect(pVtab->pChild);
    }
    pAux->bDisposed = 1;
    if( pAux->xChildDestroy ) pAux->xChildDestroy(pAux->pChildAux);
  }
}


#endif /* SQLITE_OMIT_VIRTUALTABLE */

#ifdef _WIN32
__declspec(dllexport)
#endif
int sqlite3_vtshim_init(
  sqlite3 *db, 
  char **pzErrMsg, 
  const sqlite3_api_routines *pApi
){
  SQLITE_EXTENSION_INIT2(pApi);
  return SQLITE_OK;
}