Initial work on a Win32 VFS with NOP locking.

FossilOrigin-Name: 549abe3f89b55b05a05f267865a5dd84b8cd335d

manifest

@@ -1,5 +1,5 @@
-C Another\sattempt\sto\sfix\serror\shandling\sin\sLemon.\s\sThis\schange\sis\sa\sno-op\sfor\nSQLite's\susage.
+C Initial\swork\son\sa\sWin32\sVFS\swith\sNOP\slocking.
-D 2016-07-08T19:54:38.723
+D 2016-07-08T21:14:37.641
 F Makefile.in 6c20d44f72d4564f11652b26291a214c8367e5db
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc d66d0395c38571aab3804f8db0fa20707ae4609a
@@ -368,7 +368,7 @@ F src/os.h 8e976e59eb4ca1c0fca6d35ee803e38951cb0343
 F src/os_common.h b2f4707a603e36811d9b1a13278bffd757857b85
 F src/os_setup.h c9d4553b5aaa6f73391448b265b89bed0b890faa
 F src/os_unix.c a9443cdab41d7f3cdf0df3a5aab62fd6e1c9b234
-F src/os_win.c d4b8faf8896b65818e67070711fdd00d8e620bd6
+F src/os_win.c 716af57117381c24c0eb43c8dc5a86a6496f98a7
 F src/os_win.h eb7a47aa17b26b77eb97e4823f20a00b8bda12ca
 F src/pager.c c368634b888b1c8740aea83b36bfd266f2443e60
 F src/pager.h 8ab6b6feeee4bc0439bfde7ee59ba99df98b9bc3
@@ -1402,6 +1402,7 @@ F test/wild001.test bca33f499866f04c24510d74baf1e578d4e44b1c
 F test/win32heap.test ea19770974795cff26e11575e12d422dbd16893c
 F test/win32lock.test fbf107c91d8f5512be5a5b87c4c42ab9fdd54972
 F test/win32longpath.test 169c75a3b2e43481f4a62122510210c67b08f26d
+F test/win32nolock.test ac4f08811a562e45a5755e661f45ca85892bdbbc
 F test/with1.test cef099a491eac9874f2c28bd2dc86394fb3e47b3
 F test/with2.test 2b40da883658eb74ad8ad06afabe11a408e7fb87
 F test/with3.test 511bacdbe41c49cf34f9fd1bd3245fe1575bca98
@@ -1504,7 +1505,10 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 8bb8d886ffa948cd7bc66c8c62da76bce233be2e
+P e1d8ef311cabcb96495a88404991b1416655e4a8
-R 855944636ee976f5addadf9e5d764c10
+R ba3e2959766a1594f290917f0109fdb1
-U drh
+T *branch * win32nolock
-Z 1b9ee21867274cd5ef77d7b4ebcc2052
+T *sym-win32nolock *
+T -sym-trunk *
+U mistachkin
+Z 21c6555b60ed7b3a758f8d504d1fa54f

manifest.uuid

@@ -1 +1 @@
-e1d8ef311cabcb96495a88404991b1416655e4a8
+549abe3f89b55b05a05f267865a5dd84b8cd335d

src/os_win.c

@@ -290,6 +290,17 @@ struct winFile {
 #endif
 };
 
+/*
+** The winVfsAppData structure is used for the pAppData member for all of the
+** Win32 VFS variants.
+*/
+typedef struct winVfsAppData winVfsAppData;
+struct winVfsAppData {
+  const sqlite3_io_methods *pMethod; /* The file I/O methods to use. */
+  void *pAppData;                    /* The extra pAppData, if any. */
+  BOOL bNoLock;                      /* Non-zero if locking is disabled. */
+};
+
 /*
 ** Allowed values for winFile.ctrlFlags
 */
@@ -2611,7 +2622,12 @@ static int winClose(sqlite3_file *id){
   }while( rc==0 && ++cnt < MX_CLOSE_ATTEMPT && (sqlite3_win32_sleep(100), 1) );
 #if SQLITE_OS_WINCE
 #define WINCE_DELETION_ATTEMPTS 3
+  {
+    winVfsAppData *pAppData = (winVfsAppData*)pFile->pVfs->pAppData;
+    if( pAppData==NULL || !pAppData->bNoLock ){
       winceDestroyLock(pFile);
+    }
+  }
   if( pFile->zDeleteOnClose ){
     int cnt = 0;
     while(
@@ -3343,6 +3359,44 @@ static int winUnlock(sqlite3_file *id, int locktype){
   return rc;
 }
 
+/******************************************************************************
+****************************** No-op Locking **********************************
+**
+** Of the various locking implementations available, this is by far the
+** simplest:  locking is ignored.  No attempt is made to lock the database
+** file for reading or writing.
+**
+** This locking mode is appropriate for use on read-only databases
+** (ex: databases that are burned into CD-ROM, for example.)  It can
+** also be used if the application employs some external mechanism to
+** prevent simultaneous access of the same database by two or more
+** database connections.  But there is a serious risk of database
+** corruption if this locking mode is used in situations where multiple
+** database connections are accessing the same database file at the same
+** time and one or more of those connections are writing.
+*/
+
+static int winNolockLock(sqlite3_file *id, int locktype){
+  UNUSED_PARAMETER(id);
+  UNUSED_PARAMETER(locktype);
+  return SQLITE_OK;
+}
+
+static int winNolockCheckReservedLock(sqlite3_file *id, int *pResOut){
+  UNUSED_PARAMETER(id);
+  UNUSED_PARAMETER(pResOut);
+  return SQLITE_OK;
+}
+
+static int winNolockUnlock(sqlite3_file *id, int locktype){
+  UNUSED_PARAMETER(id);
+  UNUSED_PARAMETER(locktype);
+  return SQLITE_OK;
+}
+
+/******************* End of the no-op lock implementation *********************
+******************************************************************************/
+
 /*
 ** If *pArg is initially negative then this is a query.  Set *pArg to
 ** 1 or 0 depending on whether or not bit mask of pFile->ctrlFlags is set.
@@ -4407,6 +4461,44 @@ static const sqlite3_io_methods winIoMethod = {
   winUnfetch                      /* xUnfetch */
 };
 
+/*
+** This vector defines all the methods that can operate on an
+** sqlite3_file for win32 without performing any locking.
+*/
+static const sqlite3_io_methods winIoNolockMethod = {
+  3,                              /* iVersion */
+  winClose,                       /* xClose */
+  winRead,                        /* xRead */
+  winWrite,                       /* xWrite */
+  winTruncate,                    /* xTruncate */
+  winSync,                        /* xSync */
+  winFileSize,                    /* xFileSize */
+  winNolockLock,                  /* xLock */
+  winNolockUnlock,                /* xUnlock */
+  winNolockCheckReservedLock,     /* xCheckReservedLock */
+  winFileControl,                 /* xFileControl */
+  winSectorSize,                  /* xSectorSize */
+  winDeviceCharacteristics,       /* xDeviceCharacteristics */
+  winShmMap,                      /* xShmMap */
+  winShmLock,                     /* xShmLock */
+  winShmBarrier,                  /* xShmBarrier */
+  winShmUnmap,                    /* xShmUnmap */
+  winFetch,                       /* xFetch */
+  winUnfetch                      /* xUnfetch */
+};
+
+static winVfsAppData winAppData = {
+  &winIoMethod,       /* pMethod */
+  0,                  /* pAppData */
+  0                   /* bNoLock */
+};
+
+static winVfsAppData winNolockAppData = {
+  &winIoNolockMethod, /* pMethod */
+  0,                  /* pAppData */
+  1                   /* bNoLock */
+};
+
 /****************************************************************************
 **************************** sqlite3_vfs methods ****************************
 **
@@ -4739,7 +4831,7 @@ static int winIsDir(const void *zConverted){
 ** Open a file.
 */
 static int winOpen(
-  sqlite3_vfs *pVfs,        /* Used to get maximum path name length */
+  sqlite3_vfs *pVfs,        /* Used to get maximum path length and AppData */
   const char *zName,        /* Name of the file (UTF-8) */
   sqlite3_file *id,         /* Write the SQLite file handle here */
   int flags,                /* Open mode flags */
@@ -4754,6 +4846,7 @@ static int winOpen(
 #if SQLITE_OS_WINCE
   int isTemp = 0;
 #endif
+  winVfsAppData *pAppData;
   winFile *pFile = (winFile*)id;
   void *zConverted;              /* Filename in OS encoding */
   const char *zUtf8Name = zName; /* Filename in UTF-8 encoding */
@@ -4975,8 +5068,12 @@ static int winOpen(
            "rc=%s\n", h, zUtf8Name, dwDesiredAccess, pOutFlags, pOutFlags ?
            *pOutFlags : 0, (h==INVALID_HANDLE_VALUE) ? "failed" : "ok"));
 
+  pAppData = (winVfsAppData*)pVfs->pAppData;
+
 #if SQLITE_OS_WINCE
+  {
     if( isReadWrite && eType==SQLITE_OPEN_MAIN_DB
+         && ((pAppData==NULL) || !pAppData->bNoLock)
          && (rc = winceCreateLock(zName, pFile))!=SQLITE_OK
     ){
       osCloseHandle(h);
@@ -4985,6 +5082,7 @@ static int winOpen(
       OSTRACE(("OPEN-CE-LOCK name=%s, rc=%s\n", zName, sqlite3ErrName(rc)));
       return rc;
     }
+  }
   if( isTemp ){
     pFile->zDeleteOnClose = zConverted;
   }else
@@ -4994,7 +5092,7 @@ static int winOpen(
   }
 
   sqlite3_free(zTmpname);
-  pFile->pMethod = &winIoMethod;
+  pFile->pMethod = pAppData ? pAppData->pMethod : &winIoMethod;
   pFile->pVfs = pVfs;
   pFile->h = h;
   if( isReadonly ){
@@ -5722,7 +5820,7 @@ int sqlite3_os_init(void){
     SQLITE_WIN32_MAX_PATH_BYTES, /* mxPathname */
     0,                     /* pNext */
     "win32",               /* zName */
-    0,                   /* pAppData */
+    &winAppData,           /* pAppData */
     winOpen,               /* xOpen */
     winDelete,             /* xDelete */
     winAccess,             /* xAccess */
@@ -5747,7 +5845,57 @@ int sqlite3_os_init(void){
     SQLITE_WINNT_MAX_PATH_BYTES, /* mxPathname */
     0,                     /* pNext */
     "win32-longpath",      /* zName */
-    0,                   /* pAppData */
+    &winAppData,           /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#endif
+  static sqlite3_vfs winNolockVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WIN32_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32-none",          /* zName */
+    &winNolockAppData,     /* pAppData */
+    winOpen,               /* xOpen */
+    winDelete,             /* xDelete */
+    winAccess,             /* xAccess */
+    winFullPathname,       /* xFullPathname */
+    winDlOpen,             /* xDlOpen */
+    winDlError,            /* xDlError */
+    winDlSym,              /* xDlSym */
+    winDlClose,            /* xDlClose */
+    winRandomness,         /* xRandomness */
+    winSleep,              /* xSleep */
+    winCurrentTime,        /* xCurrentTime */
+    winGetLastError,       /* xGetLastError */
+    winCurrentTimeInt64,   /* xCurrentTimeInt64 */
+    winSetSystemCall,      /* xSetSystemCall */
+    winGetSystemCall,      /* xGetSystemCall */
+    winNextSystemCall,     /* xNextSystemCall */
+  };
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  static sqlite3_vfs winLongPathNolockVfs = {
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
+    SQLITE_WINNT_MAX_PATH_BYTES, /* mxPathname */
+    0,                     /* pNext */
+    "win32-longpath-none", /* zName */
+    &winNolockAppData,     /* pAppData */
     winOpen,               /* xOpen */
     winDelete,             /* xDelete */
     winAccess,             /* xAccess */
@@ -5787,6 +5935,12 @@ int sqlite3_os_init(void){
   sqlite3_vfs_register(&winLongPathVfs, 0);
 #endif
 
+  sqlite3_vfs_register(&winNolockVfs, 0);
+
+#if defined(SQLITE_WIN32_HAS_WIDE)
+  sqlite3_vfs_register(&winLongPathNolockVfs, 0);
+#endif
+
   return SQLITE_OK;
 }
 

test/win32nolock.test

@@ -0,0 +1,126 @@
+# 2016 July 8
+#
+# 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.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library.
+#
+
+if {$tcl_platform(platform)!="windows"} return
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set testprefix win32nolock
+
+do_test win32nolock-1.0 {
+  sqlite3 db test.db
+  execsql {
+    CREATE TABLE t1(a, b);
+    BEGIN;
+    INSERT INTO t1 VALUES(1, 2);
+  }
+} {}
+
+do_test win32nolock-1.1 {
+  execsql COMMIT
+  catchsql { SELECT * FROM t1 }
+} {0 {1 2}}
+
+db close
+
+do_test win32nolock-1.2 {
+  sqlite3 db test.db -vfs win32-none
+  sqlite3 db2 test.db -vfs win32-none
+  execsql { PRAGMA mmap_size = 0 } db2
+  execsql {
+    BEGIN;
+    INSERT INTO t1 VALUES(3, 4);
+  }
+} {}
+
+do_test win32nolock-1.3 {
+  execsql { SELECT * FROM t1 }
+} {1 2 3 4}
+
+do_test win32nolock-1.4 {
+  execsql { SELECT * FROM t1; } db2
+} {1 2}
+
+do_test win32nolock-1.5 {
+  execsql {
+    BEGIN;
+    SELECT * FROM t1;
+  } db2
+} {1 2}
+
+do_test win32nolock-1.6 {
+  execsql COMMIT
+  execsql {SELECT * FROM t1} db2
+} {1 2}
+
+ifcapable memorymanage {
+  do_test win32nolock-1.7 {
+    sqlite3_release_memory 1000000
+    execsql {SELECT * FROM t1} db2
+  } {1 2 3 4}
+}
+
+do_test win32nolock-1.8 {
+  db close
+  db2 close
+} {}
+
+do_test win32nolock-1.9.1 {
+  sqlite3 db test.db
+  sqlite3 db2 test.db
+  list [catchsql { BEGIN EXCLUSIVE; } db] \
+      [catchsql { BEGIN EXCLUSIVE; } db2]
+} {{0 {}} {1 {database is locked}}}
+
+do_test win32nolock-1.9.2 {
+  db close
+  db2 close
+} {}
+
+do_test win32nolock-1.10.1 {
+  sqlite3 db test.db -vfs win32-none
+  sqlite3 db2 test.db
+  list [catchsql { BEGIN EXCLUSIVE; } db] \
+      [catchsql { BEGIN EXCLUSIVE; } db2]
+} {{0 {}} {0 {}}}
+
+do_test win32nolock-1.10.2 {
+  db close
+  db2 close
+} {}
+
+do_test win32nolock-1.11.1 {
+  sqlite3 db test.db
+  sqlite3 db2 test.db -vfs win32-none
+  list [catchsql { BEGIN EXCLUSIVE; } db] \
+      [catchsql { BEGIN EXCLUSIVE; } db2]
+} {{0 {}} {0 {}}}
+
+do_test win32nolock-1.11.2 {
+  db close
+  db2 close
+} {}
+
+do_test win32nolock-1.12.1 {
+  sqlite3 db test.db -vfs win32-none
+  sqlite3 db2 test.db -vfs win32-none
+  list [catchsql { BEGIN EXCLUSIVE; } db] \
+      [catchsql { BEGIN EXCLUSIVE; } db2]
+} {{0 {}} {0 {}}}
+
+do_test win32nolock-1.12.2 {
+  db close
+  db2 close
+} {}
+
+finish_test