Add support for the win32-none VFS.

FossilOrigin-Name: b5f32a896d0e4010ec67fcf1d635bb9aa797d3c2

1 files changed, 207 insertions, 53 deletions

diff --git a/src/os_win.c b/src/os_win.c
index edc182a01..1c861b0fb 100644
--- a/src/os_win.c
+++ b/src/os_win.c
@@ -291,6 +291,17 @@ struct winFile {
 };
 
 /*
+** 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
 */
 #define WINFILE_RDONLY          0x02   /* Connection is read only */
@@ -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
-  winceDestroyLock(pFile);
+  {
+    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 */
@@ -4975,15 +5068,20 @@ 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
-       && (rc = winceCreateLock(zName, pFile))!=SQLITE_OK
-  ){
-    osCloseHandle(h);
-    sqlite3_free(zConverted);
-    sqlite3_free(zTmpname);
-    OSTRACE(("OPEN-CE-LOCK name=%s, rc=%s\n", zName, sqlite3ErrName(rc)));
-    return rc;
+  {
+    if( isReadWrite && eType==SQLITE_OPEN_MAIN_DB
+         && ((pAppData==NULL) || !pAppData->bNoLock)
+         && (rc = winceCreateLock(zName, pFile))!=SQLITE_OK
+    ){
+      osCloseHandle(h);
+      sqlite3_free(zConverted);
+      sqlite3_free(zTmpname);
+      OSTRACE(("OPEN-CE-LOCK name=%s, rc=%s\n", zName, sqlite3ErrName(rc)));
+      return rc;
+    }
   }
   if( isTemp ){
     pFile->zDeleteOnClose = zConverted;
@@ -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 ){
@@ -5717,53 +5815,103 @@ static int winGetLastError(sqlite3_vfs *pVfs, int nBuf, char *zBuf){
 */
 int sqlite3_os_init(void){
   static sqlite3_vfs winVfs = {
-    3,                   /* iVersion */
-    sizeof(winFile),     /* szOsFile */
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
     SQLITE_WIN32_MAX_PATH_BYTES, /* mxPathname */
-    0,                   /* pNext */
-    "win32",             /* zName */
-    0,                   /* 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 */
+    0,                     /* pNext */
+    "win32",               /* zName */
+    &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 */
   };
 #if defined(SQLITE_WIN32_HAS_WIDE)
   static sqlite3_vfs winLongPathVfs = {
-    3,                   /* iVersion */
-    sizeof(winFile),     /* szOsFile */
+    3,                     /* iVersion */
+    sizeof(winFile),       /* szOsFile */
     SQLITE_WINNT_MAX_PATH_BYTES, /* mxPathname */
-    0,                   /* pNext */
-    "win32-longpath",    /* zName */
-    0,                   /* 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 */
+    0,                     /* pNext */
+    "win32-longpath",      /* zName */
+    &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 */
+    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
 
@@ -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;
 }