Prototype change for a new sqlite3_file_control() that will cause the

-wal and -shm files to persist after the last database connection closes.

FossilOrigin-Name: e34c553bf04761e86f3bd72f91439c05886caa5c

manifest

@@ -1,5 +1,5 @@
-C Enable\sthe\sSQLITE_FCNTL_SIZE_HINT\son\sunix\seven\sif\sSQLITE_FCNTL_CHUNK_SIZE\nhas\snot\sbeen\sset.
-D 2011-07-25T23:25:47.867
+C Prototype\schange\sfor\sa\snew\ssqlite3_file_control()\sthat\swill\scause\sthe\n-wal\sand\s-shm\sfiles\sto\spersist\safter\sthe\slast\sdatabase\sconnection\scloses.
+D 2011-07-26T16:03:07.413
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 1e6988b3c11dee9bd5edc0c804bd4468d74a9cdc
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -165,8 +165,8 @@ F src/os.c fcc717427a80b2ed225373f07b642dc1aad7490b
 F src/os.h 9dbed8c2b9c1f2f2ebabc09e49829d4777c26bf9
 F src/os_common.h 65a897143b64667d23ed329a7984b9b405accb58
 F src/os_os2.c 4a75888ba3dfc820ad5e8177025972d74d7f2440
-F src/os_unix.c b83e0924d1a832a89989d3d2770179205d0e066a
-F src/os_win.c 8449cb4ce1cd50248b7133108532d9582cc6c042
+F src/os_unix.c 294e8e9803454d70e796d84c77f990cc6d946899
+F src/os_win.c 313f48b6f92890f2a42d5ff6fa0fb0501d2fff25
 F src/pager.c 120550e7ef01dafaa2cbb4a0528c0d87c8f12b41
 F src/pager.h 3f8c783de1d4706b40b1ac15b64f5f896bcc78d1
 F src/parse.y 12b7ebd61ea54f0e1b1083ff69cc2c8ce9353d58
@@ -181,7 +181,7 @@ F src/resolve.c 36368f44569208fa074e61f4dd0b6c4fb60ca2b4
 F src/rowset.c 69afa95a97c524ba6faf3805e717b5b7ae85a697
 F src/select.c d219c4b68d603cc734b6f9b1e2780fee12a1fa0d
 F src/shell.c bbe7818ff5bc8614105ceb81ad67b8bdc0b671dd
-F src/sqlite.h.in badc4f56b9b57a8731475c2ddbccd8198ce33b9b
+F src/sqlite.h.in 0b3cab7b2ea51f58396e8871fa5f349cfece5330
 F src/sqlite3ext.h 1a1a4f784aa9c3b00edd287940197de52487cd93
 F src/sqliteInt.h ba4a6d6288efb25b84bc0d7d0aaf80f9b42523ba
 F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
@@ -247,7 +247,7 @@ F src/vdbeblob.c f024f0bf420f36b070143c32b15cc7287341ffd3
 F src/vdbemem.c 0498796b6ffbe45e32960d6a1f5adfb6e419883b
 F src/vdbetrace.c 5d0dc3d5fd54878cc8d6d28eb41deb8d5885b114
 F src/vtab.c 901791a47318c0562cd0c676a2c6ff1bc530e582
-F src/wal.c 0c70ad7b1cac6005fa5e2cbefd23ee05e391c290
+F src/wal.c 3154756177d6219e233d84291d5b05f4e06ff5e9
 F src/wal.h 66b40bd91bc29a5be1c88ddd1f5ade8f3f48728a
 F src/walker.c 3112bb3afe1d85dc52317cb1d752055e9a781f8f
 F src/where.c 106cd9ab3eb410dfa7d0598194c277664bb2e9a3
@@ -952,7 +952,10 @@ F tool/symbols.sh caaf6ccc7300fd43353318b44524853e222557d5
 F tool/tostr.awk 11760e1b94a5d3dcd42378f3cc18544c06cfa576
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
 F tool/warnings.sh 2ebae31e1eb352696f3c2f7706a34c084b28c262
-P 08d0e8799e1441ef063b1cdf9e4107071a0f81ca
-R 513a198a27aca1f07c596d222f883111
+P 05c9832e5f6eb705f1dce4e65cf4e2d56512ff6b
+R 89b4ef80e4aa70f9d9aab4e9774d951c
+T *branch * persistent-wal-patch
+T *sym-persistent-wal-patch *
+T -sym-trunk *
 U drh
-Z bf5f24c7092583c5f65553c09e369462
+Z fcc3b5975e3b68e4a98c8be3a9674ec5

manifest.uuid

@@ -1 +1 @@
-05c9832e5f6eb705f1dce4e65cf4e2d56512ff6b
+e34c553bf04761e86f3bd72f91439c05886caa5c

src/os_unix.c

@@ -252,6 +252,7 @@ struct unixFile {
 */
 #define UNIXFILE_EXCL        0x01     /* Connections from one process only */
 #define UNIXFILE_RDONLY      0x02     /* Connection is read only */
+#define UNIXFILE_PERSIST_WAL 0x04     /* Persistent WAL mode */
 
 /*
 ** Include code that is common to all os_*.c files
@@ -3450,21 +3451,33 @@ static int fcntlSizeHint(unixFile *pFile, i64 nByte){
 ** Information and control of an open file handle.
 */
 static int unixFileControl(sqlite3_file *id, int op, void *pArg){
+  unixFile *pFile = (unixFile*)id;
   switch( op ){
     case SQLITE_FCNTL_LOCKSTATE: {
-      *(int*)pArg = ((unixFile*)id)->eFileLock;
+      *(int*)pArg = pFile->eFileLock;
       return SQLITE_OK;
     }
     case SQLITE_LAST_ERRNO: {
-      *(int*)pArg = ((unixFile*)id)->lastErrno;
+      *(int*)pArg = pFile->lastErrno;
       return SQLITE_OK;
     }
     case SQLITE_FCNTL_CHUNK_SIZE: {
-      ((unixFile*)id)->szChunk = *(int *)pArg;
+      pFile->szChunk = *(int *)pArg;
       return SQLITE_OK;
     }
     case SQLITE_FCNTL_SIZE_HINT: {
-      return fcntlSizeHint((unixFile *)id, *(i64 *)pArg);
+      return fcntlSizeHint(pFile, *(i64 *)pArg);
+    }
+    case SQLITE_FCNTL_PERSIST_WAL: {
+      int bPersist = *(int*)pArg;
+      if( bPersist<0 ){
+        bPersist = (pFile->ctrlFlags & UNIXFILE_PERSIST_WAL)!=0;
+      }else if( bPersist==0 ){
+        pFile->ctrlFlags &= ~UNIXFILE_PERSIST_WAL;
+      }else{
+        pFile->ctrlFlags |= UNIXFILE_PERSIST_WAL;
+      }
+      return SQLITE_OK;
     }
 #ifndef NDEBUG
     /* The pager calls this method to signal that it has done

src/os_win.c

@@ -102,8 +102,9 @@ struct winFile {
   const sqlite3_io_methods *pMethod; /*** Must be first ***/
   sqlite3_vfs *pVfs;      /* The VFS used to open this file */
   HANDLE h;               /* Handle for accessing the file */
-  unsigned char locktype; /* Type of lock currently held on this file */
+  u8 locktype;            /* Type of lock currently held on this file */
   short sharedLockByte;   /* Randomly chosen byte used as a shared lock */
+  u8 bPersistWal;         /* True to persist WAL files */
   DWORD lastErrno;        /* The Windows errno from the last I/O error */
   DWORD sectorSize;       /* Sector size of the device file is on */
   winShm *pShm;           /* Instance of shared memory on this file */
@@ -1335,17 +1336,18 @@ static int winUnlock(sqlite3_file *id, int locktype){
 ** Control and query of the open file handle.
 */
 static int winFileControl(sqlite3_file *id, int op, void *pArg){
+  winFile *pFile = (winFile*)id;
   switch( op ){
     case SQLITE_FCNTL_LOCKSTATE: {
-      *(int*)pArg = ((winFile*)id)->locktype;
+      *(int*)pArg = pFile->locktype;
       return SQLITE_OK;
     }
     case SQLITE_LAST_ERRNO: {
-      *(int*)pArg = (int)((winFile*)id)->lastErrno;
+      *(int*)pArg = (int)pFile->lastErrno;
       return SQLITE_OK;
     }
     case SQLITE_FCNTL_CHUNK_SIZE: {
-      ((winFile*)id)->szChunk = *(int *)pArg;
+      pFile->szChunk = *(int *)pArg;
       return SQLITE_OK;
     }
     case SQLITE_FCNTL_SIZE_HINT: {
@@ -1355,6 +1357,15 @@ static int winFileControl(sqlite3_file *id, int op, void *pArg){
       SimulateIOErrorBenign(0);
       return SQLITE_OK;
     }
+    case SQLITE_FCNTL_PERSIST_WAL: {
+      int bPersist = *(int*)pArg;
+      if( bPersist<0 ){
+        bPersist = pFile->bPersistWal;
+      }else{
+        pFile->bPersistWal = bPersist!=0;
+      }
+      return SQLITE_OK;
+    }
     case SQLITE_FCNTL_SYNC_OMITTED: {
       return SQLITE_OK;
     }

src/sqlite.h.in

@@ -753,6 +753,20 @@ struct sqlite3_io_methods {
 ** into the array entry, allowing the current retry settings to be
 ** interrogated.  The zDbName parameter is ignored.
 **
+** ^The [SQLITE_FCNTL_PERSIST_WAL] opcode is used to set or query the
+** persistent [WAL | Write AHead Log] setting.  By default, the auxiliary
+** write ahead log and shared memory files used for transaction control
+** are automatically deleted when the latest connection to the database
+** closes.  Setting persistent WAL mode causes those files to persist after
+** close.  Persisting the files is useful when other processes that do not
+** have write permission on the directory containing the database file want
+** to read the database file, as the WAL and shared memory files must exist
+** in order for the database to be readable.  The fourth parameter to
+** [sqlite3_file_control()] for this opcode should be a pointer to an integer.
+** That integer is 0 to disable persistent WAL mode or 1 to enable persistent
+** WAL mode.  If the integer is -1, then it is overwritten with the current
+** WAL persistence setting.
+** 
 */
 #define SQLITE_FCNTL_LOCKSTATE        1
 #define SQLITE_GET_LOCKPROXYFILE      2
@@ -763,6 +777,7 @@ struct sqlite3_io_methods {
 #define SQLITE_FCNTL_FILE_POINTER     7
 #define SQLITE_FCNTL_SYNC_OMITTED     8
 #define SQLITE_FCNTL_WIN32_AV_RETRY   9
+#define SQLITE_FCNTL_PERSIST_WAL     10
 
 /*
 ** CAPI3REF: Mutex Handle

src/wal.c

@@ -1804,13 +1804,15 @@ int sqlite3WalClose(
     */
     rc = sqlite3OsLock(pWal->pDbFd, SQLITE_LOCK_EXCLUSIVE);
     if( rc==SQLITE_OK ){
+      int bPersistWal = -1;
       if( pWal->exclusiveMode==WAL_NORMAL_MODE ){
         pWal->exclusiveMode = WAL_EXCLUSIVE_MODE;
       }
       rc = sqlite3WalCheckpoint(
           pWal, SQLITE_CHECKPOINT_PASSIVE, 0, 0, sync_flags, nBuf, zBuf, 0, 0
       );
-      if( rc==SQLITE_OK ){
+      sqlite3OsFileControl(pWal->pDbFd, SQLITE_FCNTL_PERSIST_WAL, &bPersistWal);
+      if( rc==SQLITE_OK && bPersistWal!=1 ){
         isDelete = 1;
       }
     }