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

Overview
Comment:More logging code.
Downloads: Tarball | ZIP archive
Timelines: family | ancestors | descendants | both | trunk
Files: files | file ages | folders
SHA1: 94016fe5e84882bb9168e397fc6b21d22b517589
User & Date: dan 2013-10-22 16:20:41.747
Context
2013-10-22
19:04
Add "PRAGMA bt_page_dump" to access a specific bt xControl() command. This is probably a temporary solution. check-in: d00d7c08d1 user: dan tags: trunk
16:20
More logging code. check-in: 94016fe5e8 user: dan tags: trunk
2013-10-21
20:04
Continue adding logging to the btree module. Still does not work. check-in: ae62a34eb7 user: dan tags: trunk
Changes
Unified Diff Ignore Whitespace Patch
Changes to main.mk.
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
         random.o resolve.o rowset.o rtree.o select.o status.o \
         tokenize.o trigger.o \
         update.o util.o varint.o \
         vdbeapi.o vdbeaux.o vdbecodec.o vdbecursor.o \
         vdbemem.o vdbetrace.o \
         walker.o where.o utf.o

LIBOBJ += bt_unix.o bt_pager.o bt_main.o bt_varint.o kvbt.o bt_lock.o

# All of the source code files.
#
SRC = \
  $(TOP)/src/alter.c \
  $(TOP)/src/analyze.c \
  $(TOP)/src/attach.c \







|







83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
         random.o resolve.o rowset.o rtree.o select.o status.o \
         tokenize.o trigger.o \
         update.o util.o varint.o \
         vdbeapi.o vdbeaux.o vdbecodec.o vdbecursor.o \
         vdbemem.o vdbetrace.o \
         walker.o where.o utf.o

LIBOBJ += bt_unix.o bt_pager.o bt_main.o bt_varint.o kvbt.o bt_lock.o bt_log.o

# All of the source code files.
#
SRC = \
  $(TOP)/src/alter.c \
  $(TOP)/src/analyze.c \
  $(TOP)/src/attach.c \
Changes to src/btInt.h.
99
100
101
102
103
104
105



106
107
108
109
110
111
112
113
*/
int sqlite4BtPagerSetCookie(BtPager*, u32 iVal);
int sqlite4BtPagerGetCookie(BtPager*, u32 *piVal);

/*
** Return a pointer to a buffer containing the name of the pager log file.
*/



const char *sqlite4BtPagerWalFile(BtPager*);

/*
** End of bt_pager.c interface.
*************************************************************************/

/*************************************************************************
** File-system interface.







>
>
>
|







99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
*/
int sqlite4BtPagerSetCookie(BtPager*, u32 iVal);
int sqlite4BtPagerGetCookie(BtPager*, u32 *piVal);

/*
** Return a pointer to a buffer containing the name of the pager log file.
*/
#define BT_PAGERFILE_DATABASE 0
#define BT_PAGERFILE_LOG      1
#define BT_PAGERFILE_SHM      2
const char *sqlite4BtPagerFilename(BtPager*, int ePagerfile);

/*
** End of bt_pager.c interface.
*************************************************************************/

/*************************************************************************
** File-system interface.
189
190
191
192
193
194
195

196
197
198
199
200
201
202
203
204
205

206
207
208
209
210
211
212
/*
** End of bt_log.c interface.
*************************************************************************/

/*************************************************************************
** Interface to bt_lock.c functionality.
*/

typedef struct BtLock BtLock;
struct BtLock {
  /* These three are set by the bt_pager module and thereafter used by 
  ** both bt_lock and bt_pager. */
  sqlite4_env *pEnv;              /* SQLite environment */
  bt_env *pVfs;                   /* Bt environment */
  bt_file *pFd;                   /* Database file descriptor */

  /* These are used only by the bt_lock module. */
  /* todo... */

};

/* Connect and disconnect procedures */
int sqlite4BtLockConnect(BtLock*, int (*xRecover)(BtLock*));
int sqlite4BtLockDisconnect(BtLock*, int(*xCkpt)(BtLock*), int(*xDel)(BtLock*));

/* Obtain and release the WRITER lock */







>









|
>







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
/*
** End of bt_log.c interface.
*************************************************************************/

/*************************************************************************
** Interface to bt_lock.c functionality.
*/
typedef struct BtShared BtShared;
typedef struct BtLock BtLock;
struct BtLock {
  /* These three are set by the bt_pager module and thereafter used by 
  ** both bt_lock and bt_pager. */
  sqlite4_env *pEnv;              /* SQLite environment */
  bt_env *pVfs;                   /* Bt environment */
  bt_file *pFd;                   /* Database file descriptor */

  /* These are used only by the bt_lock module. */
  BtShared *pShared;              /* Shared by all handles on this file */
  BtLock *pNext;                  /* Next connection using pShared */
};

/* Connect and disconnect procedures */
int sqlite4BtLockConnect(BtLock*, int (*xRecover)(BtLock*));
int sqlite4BtLockDisconnect(BtLock*, int(*xCkpt)(BtLock*), int(*xDel)(BtLock*));

/* Obtain and release the WRITER lock */
Changes to src/bt_lock.c.
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
**    May you share freely, never taking more than you give.
**
*************************************************************************
*/

#include "btInt.h"



#include <string.h>
#include <assert.h>
#include <stdio.h>
























































/*
** Connect to the database as a read/write connection. If recovery
** is required (i.e. if this is the first connection to the db), invoke 
** the xRecover() method.
**
** Return SQLITE4_OK if successful, or an SQLite4 error code if an
** error occurs.
*/
int sqlite4BtLockConnect(BtLock *p, int (*xRecover)(BtLock*)){





















































  return xRecover(p);



}

/*
** Disconnect the read/write connection passed as the first argument
** from the database.
**
** If a checkpoint is required (i.e. if this is the last read/write







>
>




>

>
>
>
>
>
>
>
>
>
>
>
>

>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>










>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>
>
>







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
**    May you share freely, never taking more than you give.
**
*************************************************************************
*/

#include "btInt.h"

#include "sqliteInt.h"

#include <string.h>
#include <assert.h>
#include <stdio.h>

typedef struct BtFile BtFile;

/*
** Global data. All global variables used by code in this file are grouped
** into the following structure instance.
**
** pDatabase:
**   Linked list of all Database objects allocated within this process.
**   This list may not be traversed without holding the global mutex (see
**   functions enterGlobalMutex() and leaveGlobalMutex()).
*/
static struct SharedData {
  BtShared *pDatabase;            /* Linked list of all Database objects */
} gShared;

struct BtFile {
  BtFile *pNext;
  bt_file *pFd;
};

struct BtShared {
  /* Protected by the global mutex (see btLockMutexEnter()/Leave()) */
  char *zName;                    /* Canonical path to database file */
  int nName;                      /* strlen(zName) */
  int nRef;                       /* Number of handles open on this file */
  BtShared *pNext;                /* Next BtShared structure in global list */

  /* Protected by the local mutex (pClientMutex) */
  sqlite4_mutex *pClientMutex;    /* Protects the apShmChunk[] and pConn */
  int nShmChunk;                  /* Number of entries in apShmChunk[] array */
  u8 **apShmChunk;                /* Array of "shared" memory regions */
  BtLock *pLock;                  /* List of connnections to this db */

  /* Multi-process mode stuff */
  int bMultiProc;                 /* True if running in multi-process mode */
  int bReadonly;                  /* True if Database.pFile is read-only */
  bt_file *pFile;                 /* Used for locks/shm in multi-proc mode */
  BtFile *pBtFile;                /* List of deferred closes */
};

/*
** Grab the global mutex that protects the linked list of BtShared
** objects.
*/
static void btLockMutexEnter(){
  /* todo... */
}

/*
** Relinquish the mutex obtained by calling btLockMutexEnter().
*/
static void btLockMutexLeave(){
  /* todo... */
}

/*
** Connect to the database as a read/write connection. If recovery
** is required (i.e. if this is the first connection to the db), invoke 
** the xRecover() method.
**
** Return SQLITE4_OK if successful, or an SQLite4 error code if an
** error occurs.
*/
int sqlite4BtLockConnect(BtLock *p, int (*xRecover)(BtLock*)){
  sqlite4_env *pEnv = p->pEnv;
  int rc = SQLITE4_OK;
  const char *zName;
  int nName;
  BtShared *pShared;

  zName = sqlite4BtPagerFilename((BtPager*)p, BT_PAGERFILE_DATABASE);
  nName = strlen(zName);

  btLockMutexEnter();
  for(pShared=gShared.pDatabase; pShared; pShared=pShared->pNext){
    if( pShared->nName==nName && 0==memcmp(zName, pShared->zName, nName) ){
      break;
    }
  }

  if( pShared==0 ){
    sqlite4_mutex *pMutex;
    pShared = (BtShared*)sqlite4_malloc(pEnv, sizeof(BtShared) + nName + 1);
    pMutex = sqlite4_mutex_alloc(pEnv, SQLITE4_MUTEX_RECURSIVE);

    if( pShared==0 || pMutex==0 ){
      sqlite4_free(pEnv, pShared);
      sqlite4_mutex_free(pMutex);
      pShared = 0;
      pMutex = 0;
      rc = btErrorBkpt(SQLITE4_NOMEM);
    }else{
      memset(pShared, 0, sizeof(BtShared));
      pShared->nName = nName;
      pShared->zName = (char *)&pShared[1];
      memcpy(pShared->zName, zName, nName+1);
      pShared->pNext = gShared.pDatabase;
      pShared->pClientMutex = pMutex;
      gShared.pDatabase = pShared;
    }
  }

  if( rc==SQLITE4_OK ){
    pShared->nRef++;
  }
  btLockMutexLeave();

  /* Add this connection to the linked list at BtShared.pLock */
  if( rc==SQLITE4_OK ){
    sqlite4_mutex_enter(pShared->pClientMutex);
    p->pNext = pShared->pLock;
    pShared->pLock = p;
    sqlite4_mutex_leave(pShared->pClientMutex);
    p->pShared = pShared;
  }

  if( rc==SQLITE4_OK ){
    rc = xRecover(p);
  }

  return rc;
}

/*
** Disconnect the read/write connection passed as the first argument
** from the database.
**
** If a checkpoint is required (i.e. if this is the last read/write
48
49
50
51
52
53
54


55
56
57
58
59

















60
61
62
63
64
65
66
** that an error occurred while checkpointing or deleting the log file.
*/
int sqlite4BtLockDisconnect(
  BtLock *p,                      /* Locker handle */
  int (*xCkpt)(BtLock*),          /* Callback to checkpoint database */
  int (*xDel)(BtLock*)            /* Callback to delete wal+shm files */
){


  int rc;                         /* Return code */
  rc = xCkpt(p);
  if( rc==SQLITE4_OK ){
    rc = xDel(p);
  }

















  return rc;
}

int sqlite4BtLockCheckpoint(BtLock *p, int (*xCkpt)(BtLock*)){
  return xCkpt(p);
}








>
>





>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>







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
** that an error occurred while checkpointing or deleting the log file.
*/
int sqlite4BtLockDisconnect(
  BtLock *p,                      /* Locker handle */
  int (*xCkpt)(BtLock*),          /* Callback to checkpoint database */
  int (*xDel)(BtLock*)            /* Callback to delete wal+shm files */
){
  BtShared *pShared = p->pShared;
  BtLock **pp;
  int rc;                         /* Return code */
  rc = xCkpt(p);
  if( rc==SQLITE4_OK ){
    rc = xDel(p);
  }

  sqlite4_mutex_enter(pShared->pClientMutex);
  for(pp=&p->pShared->pLock; *pp!=p; pp=&(*pp)->pNext);
  *pp = (*pp)->pNext;
  sqlite4_mutex_leave(pShared->pClientMutex);

  btLockMutexEnter();
  pShared->nRef--;
  if( pShared->nRef==0 ){
    BtShared **ppS;
    for(ppS=&gShared.pDatabase; *ppS!=pShared; ppS=&(*ppS)->pNext);
    *ppS = (*ppS)->pNext;

    sqlite4_mutex_free(pShared->pClientMutex);
    sqlite4_free(p->pEnv, pShared);
  }
  btLockMutexLeave();
  return rc;
}

int sqlite4BtLockCheckpoint(BtLock *p, int (*xCkpt)(BtLock*)){
  return xCkpt(p);
}

75
76
77
78
79
80
81

82
83
84
85


86

87





88







89


















/* Obtain a READER lock. 
**
** Argument aLog points to an array of 6 frame addresses. These are the 
** first and last frames in each of log regions A, B and C. Argument 
** aLock points to the array of read-lock slots in shared memory.
*/
int sqlite4BtLockReader(BtLock *pLock, u32 *aLog, u32 *aLock){

}

int sqlite4BtLockShmMap(BtLock *pLock, int iChunk, int nByte, u8 **ppOut){
  return SQLITE4_OK;


}









































>



|
>
>
|
>

>
>
>
>
>

>
>
>
>
>
>
>
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
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
/* Obtain a READER lock. 
**
** Argument aLog points to an array of 6 frame addresses. These are the 
** first and last frames in each of log regions A, B and C. Argument 
** aLock points to the array of read-lock slots in shared memory.
*/
int sqlite4BtLockReader(BtLock *pLock, u32 *aLog, u32 *aLock){
  return SQLITE4_OK;
}

int sqlite4BtLockShmMap(BtLock *pLock, int iChunk, int nByte, u8 **ppOut){
  int rc = SQLITE4_OK;
  BtShared *pShared = pLock->pShared;
  u8 *pOut = 0;

  assert( pShared->bMultiProc==0 && pShared->bReadonly==0 );

  sqlite4_mutex_enter(pShared->pClientMutex);
  if( pShared->nShmChunk<=iChunk ){
    u8 **apNew;
    int nNew = iChunk+1;
    int nByte = sizeof(u8*)*nNew;

    apNew = (u8**)sqlite4_realloc(pLock->pEnv, pShared->apShmChunk, nByte);
    if( apNew==0 ){
      rc = btErrorBkpt(SQLITE4_NOMEM);
    }else{
      memset(&apNew[pShared->nShmChunk],0,nByte-sizeof(u8*)*pShared->nShmChunk);
      pShared->nShmChunk = nNew;
      pShared->apShmChunk = apNew;
    }
  }

  if( rc==SQLITE4_OK ){
    if( pShared->apShmChunk[iChunk]==0 ){
      pShared->apShmChunk[iChunk] = (u8*)sqlite4_malloc(pLock->pEnv, nByte);
    }
    pOut = pShared->apShmChunk[iChunk];
    if( pOut==0 ){
      rc = btErrorBkpt(SQLITE4_NOMEM);
    }
  }
  sqlite4_mutex_leave(pShared->pClientMutex);
  
  *ppOut = pOut;
  return rc;
}


Changes to src/bt_log.c.
12
13
14
15
16
17
18

19
20
21
22
23
24
25



26
27
28
29
30
31
32
*/

#include "btInt.h"

#include <string.h>
#include <assert.h>
#include <stdio.h>


/* Magic values identifying WAL file header */
#define BT_WAL_MAGIC   0xBEE1CA62
#define BT_WAL_VERSION 0x00000001

typedef struct BtWalHdr BtWalHdr;
typedef struct BtShmHdr BtShmHdr;




/*
** WAL file header. All u32 fields are stored in big-endian order on
** disk. A single WAL file may contain two of these headers - one at
** byte offset 0 and the other at offset <sector-size> (the start of
** the second disk sector in the file, according to the xSectorSize
** VFS method).







>







>
>
>







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
*/

#include "btInt.h"

#include <string.h>
#include <assert.h>
#include <stdio.h>
#include <stddef.h>

/* Magic values identifying WAL file header */
#define BT_WAL_MAGIC   0xBEE1CA62
#define BT_WAL_VERSION 0x00000001

typedef struct BtWalHdr BtWalHdr;
typedef struct BtShmHdr BtShmHdr;
typedef struct BtCkptHdr BtCkptHdr;
typedef struct BtFrameHdr BtFrameHdr;
typedef struct BtShm BtShm;

/*
** WAL file header. All u32 fields are stored in big-endian order on
** disk. A single WAL file may contain two of these headers - one at
** byte offset 0 and the other at offset <sector-size> (the start of
** the second disk sector in the file, according to the xSectorSize
** VFS method).
105
106
107
108
109
110
111
112
113
114
115



116
117
118
119
120
121
122
** from the start of it. The two hash-slot arrays remain the same size, 
** but the number of entries in the page-number array is reduced to the
** value defined below.
*/
#define HASHTABLE_NFRAME_ONE (HASHTABLE_NFRAME - (sizeof(BtShm)/sizeof(u32)))

/*
** Number of slots in hash table.
*/
#define HASHTABLE_NSLOT (HASHTABLE_NFRAME * 2)




/*
** Used to calculate hash keys.
*/
#define HASHTABLE_KEY_MUL 383


/*







|



>
>
>







109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
** from the start of it. The two hash-slot arrays remain the same size, 
** but the number of entries in the page-number array is reduced to the
** value defined below.
*/
#define HASHTABLE_NFRAME_ONE (HASHTABLE_NFRAME - (sizeof(BtShm)/sizeof(u32)))

/*
** Number of slots in a hash table.
*/
#define HASHTABLE_NSLOT (HASHTABLE_NFRAME * 2)

#define HASHTABLE_OFFSET_1 (HASHTABLE_NFRAME * sizeof(u32))
#define HASHTABLE_OFFSET_2 (HASHTABLE_OFFSET_1+HASHTABLE_NSLOT*sizeof(ht_slot))

/*
** Used to calculate hash keys.
*/
#define HASHTABLE_KEY_MUL 383


/*
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
** also run database recovery before returning. In this case, the caller
** has already obtained the required locks.
*/
int sqlite4BtLogOpen(BtPager *pPager, int bRecover, BtLog **ppLog){
  BtLock *pLock = (BtLock*)pPager;
  bt_env *pVfs = pLock->pVfs;
  sqlite4_env *pEnv = pLock->pEnv;

  const char *zWal;               /* Name of log file to open */
  BtLog *pLog;                    /* Log handle to return */

  pLog = sqlite4_malloc(pEnv, sizeof(BtLog));
  if( pLog==0 ){
    rc = SQLITE4_NOMEM;
    goto open_out;
  }
  memset(pLog, 0, sizeof(BtLog));
  pLog->pPager = pPager;

  zWal = sqlite4BtPagerWalFile(BtPager*);
  rc = pVfs->xOpen(pEnv, pVfs, zWal, 0, &pLog->pFd);

  if( rc==SQLITE4_OK && bRecover ){
    /* TODO: Run recovery... */
  }

 open_out:
  if( rc!=SQLITE4_OK ){
    sqlite4_free(pEnv, pLog);
    pLog = 0;
  }
  *ppLog = pLog;
  return rc;
}

/*
** Close the log file handle BtLog*. 
*/
int sqlite4BtLogClose(BtLog *pLog){

  sqlite4_env *pEnv = pLock->pEnv;
  bt_env *pVfs = pLock->pVfs;

  pVfs->xClose(pLock->pFd);
  sqlite4_free(pEnv, pLog);







  return SQLITE4_OK;
}

/*
** Attempt to read data for page pgno from the log file. If successful,
** the data is written into buffer aData[] (which must be at least as
** large as a database page). In this case SQLITE4_OK is returned.
**
** If the log does not contain any version of page pgno, SQLITE4_NOTFOUND
** is returned and the contents of buffer aData[] are not modified.
**
** If any other error occurs, an SQLite4 error code is returned. The final
** state of buffer aData[] is undefined in this case.
*/
int sqlite4BtLogRead(BtLog *pLog, u32 pgno, u8 *aData){

}

/*
** Return true if log is completely empty (as it is if a file zero bytes
** in size has been opened or created).
*/
static int btLogIsEmpty(BtLog *pLog){







>









|

|


















|
>
|
|

|


>
>
>
>
>
>
|














>







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
** also run database recovery before returning. In this case, the caller
** has already obtained the required locks.
*/
int sqlite4BtLogOpen(BtPager *pPager, int bRecover, BtLog **ppLog){
  BtLock *pLock = (BtLock*)pPager;
  bt_env *pVfs = pLock->pVfs;
  sqlite4_env *pEnv = pLock->pEnv;
  int rc;                         /* Return code */
  const char *zWal;               /* Name of log file to open */
  BtLog *pLog;                    /* Log handle to return */

  pLog = sqlite4_malloc(pEnv, sizeof(BtLog));
  if( pLog==0 ){
    rc = SQLITE4_NOMEM;
    goto open_out;
  }
  memset(pLog, 0, sizeof(BtLog));
  pLog->pLock = (BtLock*)pPager;

  zWal = sqlite4BtPagerFilename(pPager, BT_PAGERFILE_LOG);
  rc = pVfs->xOpen(pEnv, pVfs, zWal, 0, &pLog->pFd);

  if( rc==SQLITE4_OK && bRecover ){
    /* TODO: Run recovery... */
  }

 open_out:
  if( rc!=SQLITE4_OK ){
    sqlite4_free(pEnv, pLog);
    pLog = 0;
  }
  *ppLog = pLog;
  return rc;
}

/*
** Close the log file handle BtLog*. 
*/
int sqlite4BtLogClose(BtLog *pLog, int bCleanup){
  int rc = SQLITE4_OK;
  sqlite4_env *pEnv = pLog->pLock->pEnv;
  bt_env *pVfs = pLog->pLock->pVfs;

  pVfs->xClose(pLog->pFd);
  sqlite4_free(pEnv, pLog);

  if( bCleanup ){
    BtPager *pPager = (BtPager*)pLog->pLock;
    const char *zWal = sqlite4BtPagerFilename(pPager, BT_PAGERFILE_LOG);
    rc = pVfs->xUnlink(pEnv, pVfs, zWal);
  }

  return rc;
}

/*
** Attempt to read data for page pgno from the log file. If successful,
** the data is written into buffer aData[] (which must be at least as
** large as a database page). In this case SQLITE4_OK is returned.
**
** If the log does not contain any version of page pgno, SQLITE4_NOTFOUND
** is returned and the contents of buffer aData[] are not modified.
**
** If any other error occurs, an SQLite4 error code is returned. The final
** state of buffer aData[] is undefined in this case.
*/
int sqlite4BtLogRead(BtLog *pLog, u32 pgno, u8 *aData){
  return SQLITE4_OK;
}

/*
** Return true if log is completely empty (as it is if a file zero bytes
** in size has been opened or created).
*/
static int btLogIsEmpty(BtLog *pLog){
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

static int btLogWriteHeader(BtLog *pLog, int iHdr, BtWalHdr *pHdr){
  int rc;                         /* Return code */
  i64 iOff;                       /* File offset to write to */
  assert( iHdr==0 || iHdr==1 );

  /* Calculate a checksum for the header */
  btLogChecksum(1, pHdr, offsetof(BtWalHdr, aCksum), 0, pHdr->aCksum);

  /* Write the object to disk */
  iOff = iHdr * pLog->snapshot.nSector;
  rc = btLogWriteData(pLog, iOff, pHdr, sizeof(BtWalHdr));

  return rc;
}






static int btLogMapShm(BtLock *pLog, int iChunk){
  int rc = SQLITE4_OK;

  if( pLog->nShm<=iChunk ){

    u8 **apNew;
    int nNew = iChunk+1;

    apNew = (u8**)sqlite4_malloc(pLog->pEnv, sizeof(u8*)*nNew);
    if( apNew==0 ) return btErrorBkpt(SQLITE4_NOMEM);
    memcpy(apNew, pLog->apShm, sizeof(u8*)*pLog->nShm);
    memset(&apNew[pLog->nShm], 0, (nNew-pLog->nShm) * sizeof(u8*));
    pLog->nShm = nNew;
    pLog->apShm = apNew;
  }








|



|




>
>
>
>
>
|



>



|







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

static int btLogWriteHeader(BtLog *pLog, int iHdr, BtWalHdr *pHdr){
  int rc;                         /* Return code */
  i64 iOff;                       /* File offset to write to */
  assert( iHdr==0 || iHdr==1 );

  /* Calculate a checksum for the header */
  btLogChecksum(1, (u8*)pHdr, offsetof(BtWalHdr, aCksum), 0, pHdr->aCksum);

  /* Write the object to disk */
  iOff = iHdr * pLog->snapshot.nSector;
  rc = btLogWriteData(pLog, iOff, (u8*)pHdr, sizeof(BtWalHdr));

  return rc;
}

/*
** Ensure that shared-memory chunk iChunk is mapped and available in
** the BtLog.apShm[] array. If an error occurs, return an SQLite4 error
** code. Otherwise, SQLITE4_OK.
*/
static int btLogMapShm(BtLog *pLog, int iChunk){
  int rc = SQLITE4_OK;

  if( pLog->nShm<=iChunk ){
    sqlite4_env *pEnv = pLog->pLock->pEnv;
    u8 **apNew;
    int nNew = iChunk+1;

    apNew = (u8**)sqlite4_malloc(pEnv, sizeof(u8*)*nNew);
    if( apNew==0 ) return btErrorBkpt(SQLITE4_NOMEM);
    memcpy(apNew, pLog->apShm, sizeof(u8*)*pLog->nShm);
    memset(&apNew[pLog->nShm], 0, (nNew-pLog->nShm) * sizeof(u8*));
    pLog->nShm = nNew;
    pLog->apShm = apNew;
  }

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

/*
** Locate the iHash'th hash table in shared memory. Return it.
*/
static int btLogFindHash(
  BtLog *pLog,                    /* Log handle */
  int iHash,                      /* Hash table (numbered from 0) to find */
  volatile ht_slot **paHash,      /* OUT: Pointer to hash slots */
  volatile u32 **paPgno,          /* OUT: Pointer to page number array */
  u32 *piZero                     /* OUT: Frame associated with *paPgno[0] */
){

}





























static int btLogFrameHash(BtLock *pLog, u32 iFrame){


}

/*
** Return a hash key for page number pgno.
*/
static int btLogHashKey(BtLog *pLog, u32 pgno){
  assert( pgno>=1 );
  return ((pgno * HASHTABLE_KEY_MUL) % HASHTABLE_NSLOT);
}
static int btLogHashNext(BtLog *pLog, int iSlot){
  return ((iSlot + 1) % HASHTABLE_NSLOT);
}

/*
** Add an entry mapping database page pgno to log frame iFrame to the
** the shared hash table. Return SQLITE4_OK if successful, or an SQLite4
** error code if an error occurs.
*/
static int btLogHashInsert(BtLog *pLog, u32 pgno, u32 iFrame){

  int rc = SQLITE4_OK;




  assert( iFrame>=1 && pgno>=1 );
  assert( iFrame==(pLog->snapshot.aLog[5]+1) );

  /* Find the required hash table */
  iHash = btLogFrameHash(pLog, iFrame);
  rc = btLogFindHash(pLog, iHash, &aHash, &aPgno, &iZero);

  /* Update the hash table */
  if( rc==SQLITE4_OK ){

    int nCollide = HASHTABLE_NSLOT*2;
    int iKey = btLogHashKey(pLog, pgno);
    aPgno[iFrame-iZero] = pgno;

    for(iSlot=btLogHashKey(pLog,pgno); ; iSlot=btLogHashNext(pLog, iSlot)){
      if( aHash[iSlot]==0 ){
        aHash[iSlot] = (iFrame-iZero+1);
        break;
      }
      if( (nCollide--)==0 ) return btErrorBkpt(SQLITE4_CORRUPT);
    }
  }

  return rc;
}

static int btLogUpdateSharedHdr(BtLog *pLog){
  bt_env *pVfs = pLog->pLock->pVfs;
  BtShmHdr *p = &pLog->snapshot;
  BtShm *pShm = btLogShm(pLog);

  /* Calculate a checksum for the private snapshot object. */
  btLogChecksum(1, p, offset(BtShmHdr, aCksum), 0, p->aCksum);

  /* Update the shared object. */
  pVfs->xShmBarrier(pLog->pFd);
  memcpy(&pShm->hdr1, p, sizeof(BtShmHdr));
  pVfs->xShmBarrier(pLog->pFd);
  memcpy(&pShm->hdr2, p, sizeof(BtShmHdr));

  return SQLITE4_OK;
}








/*
** Write a frame to the log file.
*/
int sqlite4BtLogWrite(BtLog *pLog, u32 pgno, u8 *aData, int bCommit){

  int rc = SQLITE4_OK;
  u32 iFrame;                     /* Write this frame (numbered from 1) */
  BtFrameHdr frame;               /* Header for new frame */
  u32 *aFrameCksum;               /* Pointer to cksum of previous frame */


  /* Handle a special case - if the log file is completely empty then
  ** this writer must write the first header into the WAL file. */
  if( btLogIsEmpty(pLog) ){
    BtWalHdr hdr;
    memset(&hdr, 0, sizeof(BtWalHdr));

    hdr.iMagic = BT_WAL_MAGIC;
    hdr.iVersion = BT_WAL_VERSION;
    hdr.nSector = pLog->snapshot.nSector;
    hdr.iSalt1 = 22;
    hdr.iSalt2 = 23;
    hdr.iFirstFrame = 1;

    rc = btLogWriteHeader(pLog, 0, &hdr);
    if( rc!=SQLITE4_OK ) return rc;
  }

  /* Figure out where exactly to write the new data */
  iFrame = pLog->snapshot.aLog[5] + 1;
  iOff = btLogFrameOffset(pLog, iFrame);

  /* Populate the frame header object. */
  memset(&frame, 0, sizeof(frame));
  frame.pgno = pgno;
  frame.ctrl = (bCommit ? 0x80000000 : 0x00000000);
  aFrameCksum = pLog->snapshot.aFrameCksum;
  btLogChecksum(1, &frame, offsetof(aCksum), aFrameCksum, frame.aCksum);
  btLogChecksum(1, aData, pgsz, frame.aCksum, frame.aCksum);

  /* Write the header and page record to the log file. */
  rc = btLogWriteData(pLog, iOff, &frame, sizeof(frame));
  if( rc==SQLITE4_OK ){
    rc = btLogWriteData(pLog, iOff+sizeof(frame), aData, pgsz);
  }

  /* Update the wal index hash tables with the (pgno -> iFrame) record. */
  if( rc==SQLITE4_OK ){
    rc = btLogHashInsert(pLog, pgno, iFrame);







|
|


>
|
>
>
>
>
>

>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
|
>
>



















>
|
>
>
>










>

<




















|









>
>
>
>
>
>
>





>



|
>




















|





|
|



|







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
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484

/*
** Locate the iHash'th hash table in shared memory. Return it.
*/
static int btLogFindHash(
  BtLog *pLog,                    /* Log handle */
  int iHash,                      /* Hash table (numbered from 0) to find */
  ht_slot **paHash,               /* OUT: Pointer to hash slots */
  u32 **paPgno,                   /* OUT: Pointer to page number array */
  u32 *piZero                     /* OUT: Frame associated with *paPgno[0] */
){
  int rc;

  rc = btLogMapShm(pLog, iHash);
  if( rc==SQLITE4_OK ){
    u8 *aChunk = pLog->apShm[iHash];
    u32 *aPgno;
    u32 iZero;

    *paHash = (ht_slot*)&aChunk[HASHTABLE_OFFSET_1];
    if( iHash==0 ){
      aPgno = (u32*)&aChunk[sizeof(BtShm)];
      iZero = 1;
    }else{
      aPgno = (u32*)aChunk;
      iZero = 1 + HASHTABLE_NFRAME_ONE + (HASHTABLE_NFRAME * (iHash-1));
    }
    *paPgno = aPgno;
    *piZero = iZero;
  }

  return rc;
}

static BtShm *btLogShm(BtLog *pLog){
  return (BtShm*)(pLog->apShm[0]);
}

/*
** Return the index of the hash table that contains the entry for frame
** iFrame. 
*/
static int btLogFrameHash(BtLog *pLog, u32 iFrame){
  if( iFrame<=HASHTABLE_NFRAME_ONE ) return 0;
  return 1 + ((iFrame - HASHTABLE_NFRAME_ONE - 1) / HASHTABLE_NFRAME);
}

/*
** Return a hash key for page number pgno.
*/
static int btLogHashKey(BtLog *pLog, u32 pgno){
  assert( pgno>=1 );
  return ((pgno * HASHTABLE_KEY_MUL) % HASHTABLE_NSLOT);
}
static int btLogHashNext(BtLog *pLog, int iSlot){
  return ((iSlot + 1) % HASHTABLE_NSLOT);
}

/*
** Add an entry mapping database page pgno to log frame iFrame to the
** the shared hash table. Return SQLITE4_OK if successful, or an SQLite4
** error code if an error occurs.
*/
static int btLogHashInsert(BtLog *pLog, u32 pgno, u32 iFrame){
  int iHash;                      /* Index of hash table to update */
  int rc = SQLITE4_OK;            /* Return code */
  ht_slot *aHash;                 /* Hash slots */
  u32 *aPgno;                     /* Page array for updated hash table */
  u32 iZero;                      /* Zero-offset of updated hash table */

  assert( iFrame>=1 && pgno>=1 );
  assert( iFrame==(pLog->snapshot.aLog[5]+1) );

  /* Find the required hash table */
  iHash = btLogFrameHash(pLog, iFrame);
  rc = btLogFindHash(pLog, iHash, &aHash, &aPgno, &iZero);

  /* Update the hash table */
  if( rc==SQLITE4_OK ){
    int iSlot;
    int nCollide = HASHTABLE_NSLOT*2;

    aPgno[iFrame-iZero] = pgno;

    for(iSlot=btLogHashKey(pLog,pgno); ; iSlot=btLogHashNext(pLog, iSlot)){
      if( aHash[iSlot]==0 ){
        aHash[iSlot] = (iFrame-iZero+1);
        break;
      }
      if( (nCollide--)==0 ) return btErrorBkpt(SQLITE4_CORRUPT);
    }
  }

  return rc;
}

static int btLogUpdateSharedHdr(BtLog *pLog){
  bt_env *pVfs = pLog->pLock->pVfs;
  BtShmHdr *p = &pLog->snapshot;
  BtShm *pShm = btLogShm(pLog);

  /* Calculate a checksum for the private snapshot object. */
  btLogChecksum(1, (u8*)p, offsetof(BtShmHdr, aCksum), 0, p->aCksum);

  /* Update the shared object. */
  pVfs->xShmBarrier(pLog->pFd);
  memcpy(&pShm->hdr1, p, sizeof(BtShmHdr));
  pVfs->xShmBarrier(pLog->pFd);
  memcpy(&pShm->hdr2, p, sizeof(BtShmHdr));

  return SQLITE4_OK;
}

/*
** Return the offset of frame iFrame within the log file.
*/
static i64 btLogFrameOffset(BtLog *pLog, int pgsz, u32 iFrame){
  return (i64)pLog->snapshot.nSector*2 + (i64)(iFrame-1) * (i64)pgsz;
}

/*
** Write a frame to the log file.
*/
int sqlite4BtLogWrite(BtLog *pLog, u32 pgno, u8 *aData, int bCommit){
  const int pgsz = sqlite4BtPagerPagesize((BtPager*)(pLog->pLock));
  int rc = SQLITE4_OK;
  u32 iFrame;                     /* Write this frame (numbered from 1) */
  BtFrameHdr frame;               /* Header for new frame */
  u32 *a;                         /* Pointer to cksum of previous frame */
  i64 iOff;                       /* Offset of log file to write to */

  /* Handle a special case - if the log file is completely empty then
  ** this writer must write the first header into the WAL file. */
  if( btLogIsEmpty(pLog) ){
    BtWalHdr hdr;
    memset(&hdr, 0, sizeof(BtWalHdr));

    hdr.iMagic = BT_WAL_MAGIC;
    hdr.iVersion = BT_WAL_VERSION;
    hdr.nSector = pLog->snapshot.nSector;
    hdr.iSalt1 = 22;
    hdr.iSalt2 = 23;
    hdr.iFirstFrame = 1;

    rc = btLogWriteHeader(pLog, 0, &hdr);
    if( rc!=SQLITE4_OK ) return rc;
  }

  /* Figure out where exactly to write the new data */
  iFrame = pLog->snapshot.aLog[5] + 1;
  iOff = btLogFrameOffset(pLog, pgsz, iFrame);

  /* Populate the frame header object. */
  memset(&frame, 0, sizeof(frame));
  frame.pgno = pgno;
  frame.ctrl = (bCommit ? 0x80000000 : 0x00000000);
  a = pLog->snapshot.aFrameCksum;
  btLogChecksum(1, (u8*)&frame, offsetof(BtFrameHdr, aCksum), a, frame.aCksum);
  btLogChecksum(1, aData, pgsz, frame.aCksum, frame.aCksum);

  /* Write the header and page record to the log file. */
  rc = btLogWriteData(pLog, iOff, (u8*)&frame, sizeof(frame));
  if( rc==SQLITE4_OK ){
    rc = btLogWriteData(pLog, iOff+sizeof(frame), aData, pgsz);
  }

  /* Update the wal index hash tables with the (pgno -> iFrame) record. */
  if( rc==SQLITE4_OK ){
    rc = btLogHashInsert(pLog, pgno, iFrame);
443
444
445
446
447
448
449
450

451


int sqlite4BtLogSnapshotClose(BtLog *pLog){
  return SQLITE4_OK;
}

int sqlite4BtLogSnapshotWritable(BtLog *pLog){
  return 1;
}













>
|
>
>
509
510
511
512
513
514
515
516
517
518
519
520
int sqlite4BtLogSnapshotClose(BtLog *pLog){
  return SQLITE4_OK;
}

int sqlite4BtLogSnapshotWritable(BtLog *pLog){
  return 1;
}

int sqlite4BtLogCheckpoint(BtLog *pLog){
}


Changes to src/bt_pager.c.
63
64
65
66
67
68
69

70
71
72
73
74
75
76
};

/*
** Pager object.
*/
struct BtPager {
  BtLock btl;                     /* Variables shared with bt_lock module */

  int iTransactionLevel;          /* Current transaction level (see bt.h) */
  char *zFile;                    /* Database file name */
  int nFile;                      /* Length of string zFile in bytes */
  BtPageHash hash;                /* Hash table */
  BtPage *pDirty;                 /* List of all dirty pages */
  BtDbhdr dbhdr;
  int nTotalRef;







>







63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
};

/*
** Pager object.
*/
struct BtPager {
  BtLock btl;                     /* Variables shared with bt_lock module */
  BtLog *pLog;                    /* Logging module */
  int iTransactionLevel;          /* Current transaction level (see bt.h) */
  char *zFile;                    /* Database file name */
  int nFile;                      /* Length of string zFile in bytes */
  BtPageHash hash;                /* Hash table */
  BtPage *pDirty;                 /* List of all dirty pages */
  BtDbhdr dbhdr;
  int nTotalRef;
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
  int rc;
  rc = sqlite4BtLogOpen(p, 1, &p->pLog);
  return rc;
}

static int btCheckpoint(BtLock *pLock){
  BtPager *p = (BtPager*)pLock;
  sqlite4BtLogCheckpoint(p->pLog);
}

static int btCleanup(BtLock *pLock){
  BtPager *p = (BtPager*)pLock;
  int rc = sqlite4BtLogClose(p->pLog, 1);
  return rc;
}







|







247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
  int rc;
  rc = sqlite4BtLogOpen(p, 1, &p->pLog);
  return rc;
}

static int btCheckpoint(BtLock *pLock){
  BtPager *p = (BtPager*)pLock;
  return sqlite4BtLogCheckpoint(p->pLog);
}

static int btCleanup(BtLock *pLock){
  BtPager *p = (BtPager*)pLock;
  int rc = sqlite4BtLogClose(p->pLog, 1);
  return rc;
}
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
  }

  /* If the database file was successfully opened, connect to the
  ** database and open the database logger. */
  if( rc==SQLITE4_OK ){
    rc = sqlite4BtLockConnect((BtLock*)p, btRecover);
    if( rc==SQLITE4_OK && p->pLog==0 ){
      rc = sqlite4BtLogOpen(pPager, 0, &p->pLog);
    }
  }

  assert( (rc==SQLITE4_OK)==(p->btl.pFd!=0 && p->pLog!=0) );
  return rc;
}








|







284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
  }

  /* If the database file was successfully opened, connect to the
  ** database and open the database logger. */
  if( rc==SQLITE4_OK ){
    rc = sqlite4BtLockConnect((BtLock*)p, btRecover);
    if( rc==SQLITE4_OK && p->pLog==0 ){
      rc = sqlite4BtLogOpen(p, 0, &p->pLog);
    }
  }

  assert( (rc==SQLITE4_OK)==(p->btl.pFd!=0 && p->pLog!=0) );
  return rc;
}

634
635
636
637
638
639
640
641
642















643
644
645
646
647
648
649
650
651
652
*/
int sqlite4BtPagerGetCookie(BtPager *p, u32 *piVal){
  assert( p->iTransactionLevel>=1 );
  *piVal = p->dbhdr.cookie;
  return SQLITE4_OK;
}

const char *sqlite4BtPagerWalFile(BtPager *p){
  const char *zTail = "-wal";















  memcpy(&p->zFile[p->nFile], zTail, strlen(zTail)+1);
  return p->zFile;
}

#ifndef NDEBUG
int sqlite4BtPagerRefcount(BtPager *p){
  return p->nTotalRef;
}
#endif








|
|
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>










635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
*/
int sqlite4BtPagerGetCookie(BtPager *p, u32 *piVal){
  assert( p->iTransactionLevel>=1 );
  *piVal = p->dbhdr.cookie;
  return SQLITE4_OK;
}

const char *sqlite4BtPagerFilename(BtPager *p, int ePagerfile){
  const char *zTail;

  switch( ePagerfile ){
    case BT_PAGERFILE_DATABASE:
      zTail = "";
      break;

    case BT_PAGERFILE_LOG:
      zTail = "-wal";
      break;

    default:
      assert( ePagerfile==BT_PAGERFILE_SHM );
      zTail = "-shm";
      break;
  }
  memcpy(&p->zFile[p->nFile], zTail, strlen(zTail)+1);
  return p->zFile;
}

#ifndef NDEBUG
int sqlite4BtPagerRefcount(BtPager *p){
  return p->nTotalRef;
}
#endif