Imported Upstream version 2.0.3

1 files changed, 1105 insertions, 0 deletions

diff --git a/src/test_quota.c b/src/test_quota.c
new file mode 100644
index 0000000..74d1a6d
--- /dev/null
+++ b/src/test_quota.c
@@ -0,0 +1,1105 @@
+/*
+** 2010 September 31
+**
+** 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 contains a VFS "shim" - a layer that sits in between the
+** pager and the real VFS.
+**
+** This particular shim enforces a quota system on files.  One or more
+** database files are in a "quota group" that is defined by a GLOB
+** pattern.  A quota is set for the combined size of all files in the
+** the group.  A quota of zero means "no limit".  If the total size
+** of all files in the quota group is greater than the limit, then
+** write requests that attempt to enlarge a file fail with SQLITE_FULL.
+**
+** However, before returning SQLITE_FULL, the write requests invoke
+** a callback function that is configurable for each quota group.
+** This callback has the opportunity to enlarge the quota.  If the
+** callback does enlarge the quota such that the total size of all
+** files within the group is less than the new quota, then the write
+** continues as if nothing had happened.
+*/
+#include "sqlite3.h"
+#include <string.h>
+#include <assert.h>
+
+/*
+** For an build without mutexes, no-op the mutex calls.
+*/
+#if defined(SQLITE_THREADSAFE) && SQLITE_THREADSAFE==0
+#define sqlite3_mutex_alloc(X)    ((sqlite3_mutex*)8)
+#define sqlite3_mutex_free(X)
+#define sqlite3_mutex_enter(X)
+#define sqlite3_mutex_try(X)      SQLITE_OK
+#define sqlite3_mutex_leave(X)
+#define sqlite3_mutex_held(X)     ((void)(X),1)
+#define sqlite3_mutex_notheld(X)  ((void)(X),1)
+#endif /* SQLITE_THREADSAFE==0 */
+
+
+/************************ Object Definitions ******************************/
+
+/* Forward declaration of all object types */
+typedef struct quotaGroup quotaGroup;
+typedef struct quotaConn quotaConn;
+typedef struct quotaFile quotaFile;
+
+/*
+** A "quota group" is a collection of files whose collective size we want
+** to limit.  Each quota group is defined by a GLOB pattern.
+**
+** There is an instance of the following object for each defined quota
+** group.  This object records the GLOB pattern that defines which files
+** belong to the quota group.  The object also remembers the size limit
+** for the group (the quota) and the callback to be invoked when the
+** sum of the sizes of the files within the group goes over the limit.
+**
+** A quota group must be established (using sqlite3_quota_set(...))
+** prior to opening any of the database connections that access files
+** within the quota group.
+*/
+struct quotaGroup {
+  const char *zPattern;          /* Filename pattern to be quotaed */
+  sqlite3_int64 iLimit;          /* Upper bound on total file size */
+  sqlite3_int64 iSize;           /* Current size of all files */
+  void (*xCallback)(             /* Callback invoked when going over quota */
+     const char *zFilename,         /* Name of file whose size increases */
+     sqlite3_int64 *piLimit,        /* IN/OUT: The current limit */
+     sqlite3_int64 iSize,           /* Total size of all files in the group */
+     void *pArg                     /* Client data */
+  );
+  void *pArg;                    /* Third argument to the xCallback() */
+  void (*xDestroy)(void*);       /* Optional destructor for pArg */
+  quotaGroup *pNext, **ppPrev;   /* Doubly linked list of all quota objects */
+  quotaFile *pFiles;             /* Files within this group */
+};
+
+/*
+** An instance of this structure represents a single file that is part
+** of a quota group.  A single file can be opened multiple times.  In
+** order keep multiple openings of the same file from causing the size
+** of the file to count against the quota multiple times, each file
+** has a unique instance of this object and multiple open connections
+** to the same file each point to a single instance of this object.
+*/
+struct quotaFile {
+  char *zFilename;                /* Name of this file */
+  quotaGroup *pGroup;             /* Quota group to which this file belongs */
+  sqlite3_int64 iSize;            /* Current size of this file */
+  int nRef;                       /* Number of times this file is open */
+  int deleteOnClose;              /* True to delete this file when it closes */
+  quotaFile *pNext, **ppPrev;     /* Linked list of files in the same group */
+};
+
+/*
+** An instance of the following object represents each open connection
+** to a file that participates in quota tracking.  This object is a 
+** subclass of sqlite3_file.  The sqlite3_file object for the underlying
+** VFS is appended to this structure.
+*/
+struct quotaConn {
+  sqlite3_file base;              /* Base class - must be first */
+  quotaFile *pFile;               /* The underlying file */
+  /* The underlying VFS sqlite3_file is appended to this object */
+};
+
+/************************* Global Variables **********************************/
+/*
+** All global variables used by this file are containing within the following
+** gQuota structure.
+*/
+static struct {
+  /* The pOrigVfs is the real, original underlying VFS implementation.
+  ** Most operations pass-through to the real VFS.  This value is read-only
+  ** during operation.  It is only modified at start-time and thus does not
+  ** require a mutex.
+  */
+  sqlite3_vfs *pOrigVfs;
+
+  /* The sThisVfs is the VFS structure used by this shim.  It is initialized
+  ** at start-time and thus does not require a mutex
+  */
+  sqlite3_vfs sThisVfs;
+
+  /* The sIoMethods defines the methods used by sqlite3_file objects 
+  ** associated with this shim.  It is initialized at start-time and does
+  ** not require a mutex.
+  **
+  ** When the underlying VFS is called to open a file, it might return 
+  ** either a version 1 or a version 2 sqlite3_file object.  This shim
+  ** has to create a wrapper sqlite3_file of the same version.  Hence
+  ** there are two I/O method structures, one for version 1 and the other
+  ** for version 2.
+  */
+  sqlite3_io_methods sIoMethodsV1;
+  sqlite3_io_methods sIoMethodsV2;
+
+  /* True when this shim as been initialized.
+  */
+  int isInitialized;
+
+  /* For run-time access any of the other global data structures in this
+  ** shim, the following mutex must be held.
+  */
+  sqlite3_mutex *pMutex;
+
+  /* List of quotaGroup objects.
+  */
+  quotaGroup *pGroup;
+
+} gQuota;
+
+/************************* Utility Routines *********************************/
+/*
+** Acquire and release the mutex used to serialize access to the
+** list of quotaGroups.
+*/
+static void quotaEnter(void){ sqlite3_mutex_enter(gQuota.pMutex); }
+static void quotaLeave(void){ sqlite3_mutex_leave(gQuota.pMutex); }
+
+/* Count the number of open files in a quotaGroup 
+*/
+static int quotaGroupOpenFileCount(quotaGroup *pGroup){
+  int N = 0;
+  quotaFile *pFile = pGroup->pFiles;
+  while( pFile ){
+    if( pFile->nRef ) N++;
+    pFile = pFile->pNext;
+  }
+  return N;
+}
+
+/* Remove a file from a quota group.
+*/
+static void quotaRemoveFile(quotaFile *pFile){
+  quotaGroup *pGroup = pFile->pGroup;
+  pGroup->iSize -= pFile->iSize;
+  *pFile->ppPrev = pFile->pNext;
+  if( pFile->pNext ) pFile->pNext->ppPrev = pFile->ppPrev;
+  sqlite3_free(pFile);
+}
+
+/* Remove all files from a quota group.  It is always the case that
+** all files will be closed when this routine is called.
+*/
+static void quotaRemoveAllFiles(quotaGroup *pGroup){
+  while( pGroup->pFiles ){
+    assert( pGroup->pFiles->nRef==0 );
+    quotaRemoveFile(pGroup->pFiles);
+  }
+}
+
+
+/* If the reference count and threshold for a quotaGroup are both
+** zero, then destroy the quotaGroup.
+*/
+static void quotaGroupDeref(quotaGroup *pGroup){
+  if( pGroup->iLimit==0 && quotaGroupOpenFileCount(pGroup)==0 ){
+    quotaRemoveAllFiles(pGroup);
+    *pGroup->ppPrev = pGroup->pNext;
+    if( pGroup->pNext ) pGroup->pNext->ppPrev = pGroup->ppPrev;
+    if( pGroup->xDestroy ) pGroup->xDestroy(pGroup->pArg);
+    sqlite3_free(pGroup);
+  }
+}
+
+/*
+** Return TRUE if string z matches glob pattern zGlob.
+**
+** Globbing rules:
+**
+**      '*'       Matches any sequence of zero or more characters.
+**
+**      '?'       Matches exactly one character.
+**
+**     [...]      Matches one character from the enclosed list of
+**                characters.
+**
+**     [^...]     Matches one character not in the enclosed list.
+**
+*/
+static int quotaStrglob(const char *zGlob, const char *z){
+  int c, c2;
+  int invert;
+  int seen;
+
+  while( (c = (*(zGlob++)))!=0 ){
+    if( c=='*' ){
+      while( (c=(*(zGlob++))) == '*' || c=='?' ){
+        if( c=='?' && (*(z++))==0 ) return 0;
+      }
+      if( c==0 ){
+        return 1;
+      }else if( c=='[' ){
+        while( *z && quotaStrglob(zGlob-1,z)==0 ){
+          z++;
+        }
+        return (*z)!=0;
+      }
+      while( (c2 = (*(z++)))!=0 ){
+        while( c2!=c ){
+          c2 = *(z++);
+          if( c2==0 ) return 0;
+        }
+        if( quotaStrglob(zGlob,z) ) return 1;
+      }
+      return 0;
+    }else if( c=='?' ){
+      if( (*(z++))==0 ) return 0;
+    }else if( c=='[' ){
+      int prior_c = 0;
+      seen = 0;
+      invert = 0;
+      c = *(z++);
+      if( c==0 ) return 0;
+      c2 = *(zGlob++);
+      if( c2=='^' ){
+        invert = 1;
+        c2 = *(zGlob++);
+      }
+      if( c2==']' ){
+        if( c==']' ) seen = 1;
+        c2 = *(zGlob++);
+      }
+      while( c2 && c2!=']' ){
+        if( c2=='-' && zGlob[0]!=']' && zGlob[0]!=0 && prior_c>0 ){
+          c2 = *(zGlob++);
+          if( c>=prior_c && c<=c2 ) seen = 1;
+          prior_c = 0;
+        }else{
+          if( c==c2 ){
+            seen = 1;
+          }
+          prior_c = c2;
+        }
+        c2 = *(zGlob++);
+      }
+      if( c2==0 || (seen ^ invert)==0 ) return 0;
+    }else{
+      if( c!=(*(z++)) ) return 0;
+    }
+  }
+  return *z==0;
+}
+
+
+/* Find a quotaGroup given the filename.
+**
+** Return a pointer to the quotaGroup object. Return NULL if not found.
+*/
+static quotaGroup *quotaGroupFind(const char *zFilename){
+  quotaGroup *p;
+  for(p=gQuota.pGroup; p && quotaStrglob(p->zPattern, zFilename)==0;
+      p=p->pNext){}
+  return p;
+}
+
+/* Translate an sqlite3_file* that is really a quotaConn* into
+** the sqlite3_file* for the underlying original VFS.
+*/
+static sqlite3_file *quotaSubOpen(sqlite3_file *pConn){
+  quotaConn *p = (quotaConn*)pConn;
+  return (sqlite3_file*)&p[1];
+}
+
+/* Find a file in a quota group and return a pointer to that file.
+** Return NULL if the file is not in the group.
+*/
+static quotaFile *quotaFindFile(quotaGroup *pGroup, const char *zName){
+  quotaFile *pFile = pGroup->pFiles;
+  while( pFile && strcmp(pFile->zFilename, zName)!=0 ){
+    pFile = pFile->pNext;
+  }
+  return pFile;
+}
+
+/************************* VFS Method Wrappers *****************************/
+/*
+** This is the xOpen method used for the "quota" VFS.
+**
+** Most of the work is done by the underlying original VFS.  This method
+** simply links the new file into the appropriate quota group if it is a
+** file that needs to be tracked.
+*/
+static int quotaOpen(
+  sqlite3_vfs *pVfs,          /* The quota VFS */
+  const char *zName,          /* Name of file to be opened */
+  sqlite3_file *pConn,        /* Fill in this file descriptor */
+  int flags,                  /* Flags to control the opening */
+  int *pOutFlags              /* Flags showing results of opening */
+){
+  int rc;                                    /* Result code */         
+  quotaConn *pQuotaOpen;                     /* The new quota file descriptor */
+  quotaFile *pFile;                          /* Corresponding quotaFile obj */
+  quotaGroup *pGroup;                        /* The group file belongs to */
+  sqlite3_file *pSubOpen;                    /* Real file descriptor */
+  sqlite3_vfs *pOrigVfs = gQuota.pOrigVfs;   /* Real VFS */
+
+  /* If the file is not a main database file or a WAL, then use the
+  ** normal xOpen method.
+  */
+  if( (flags & (SQLITE_OPEN_MAIN_DB|SQLITE_OPEN_WAL))==0 ){
+    return pOrigVfs->xOpen(pOrigVfs, zName, pConn, flags, pOutFlags);
+  }
+
+  /* If the name of the file does not match any quota group, then
+  ** use the normal xOpen method.
+  */
+  quotaEnter();
+  pGroup = quotaGroupFind(zName);
+  if( pGroup==0 ){
+    rc = pOrigVfs->xOpen(pOrigVfs, zName, pConn, flags, pOutFlags);
+  }else{
+    /* If we get to this point, it means the file needs to be quota tracked.
+    */
+    pQuotaOpen = (quotaConn*)pConn;
+    pSubOpen = quotaSubOpen(pConn);
+    rc = pOrigVfs->xOpen(pOrigVfs, zName, pSubOpen, flags, pOutFlags);
+    if( rc==SQLITE_OK ){
+      pFile = quotaFindFile(pGroup, zName);
+      if( pFile==0 ){
+        int nName = strlen(zName);
+        pFile = (quotaFile *)sqlite3_malloc( sizeof(*pFile) + nName + 1 );
+        if( pFile==0 ){
+          quotaLeave();
+          pSubOpen->pMethods->xClose(pSubOpen);
+          return SQLITE_NOMEM;
+        }
+        memset(pFile, 0, sizeof(*pFile));
+        pFile->zFilename = (char*)&pFile[1];
+        memcpy(pFile->zFilename, zName, nName+1);
+        pFile->pNext = pGroup->pFiles;
+        if( pGroup->pFiles ) pGroup->pFiles->ppPrev = &pFile->pNext;
+        pFile->ppPrev = &pGroup->pFiles;
+        pGroup->pFiles = pFile;
+        pFile->pGroup = pGroup;
+        pFile->deleteOnClose = (flags & SQLITE_OPEN_DELETEONCLOSE)!=0;
+      }
+      pFile->nRef++;
+      pQuotaOpen->pFile = pFile;
+      if( pSubOpen->pMethods->iVersion==1 ){
+        pQuotaOpen->base.pMethods = &gQuota.sIoMethodsV1;
+      }else{
+        pQuotaOpen->base.pMethods = &gQuota.sIoMethodsV2;
+      }
+    }
+  }
+  quotaLeave();
+  return rc;
+}
+
+/*
+** This is the xDelete method used for the "quota" VFS.
+**
+** If the file being deleted is part of the quota group, then reduce
+** the size of the quota group accordingly.  And remove the file from
+** the set of files in the quota group.
+*/
+static int quotaDelete(
+  sqlite3_vfs *pVfs,          /* The quota VFS */
+  const char *zName,          /* Name of file to be deleted */
+  int syncDir                 /* Do a directory sync after deleting */
+){
+  int rc;                                    /* Result code */         
+  quotaFile *pFile;                          /* Files in the quota */
+  quotaGroup *pGroup;                        /* The group file belongs to */
+  sqlite3_vfs *pOrigVfs = gQuota.pOrigVfs;   /* Real VFS */
+
+  /* Do the actual file delete */
+  rc = pOrigVfs->xDelete(pOrigVfs, zName, syncDir);
+
+  /* If the file just deleted is a member of a quota group, then remove
+  ** it from that quota group.
+  */
+  if( rc==SQLITE_OK ){
+    quotaEnter();
+    pGroup = quotaGroupFind(zName);
+    if( pGroup ){
+      pFile = quotaFindFile(pGroup, zName);
+      if( pFile ){
+        if( pFile->nRef ){
+          pFile->deleteOnClose = 1;
+        }else{
+          quotaRemoveFile(pFile);
+          quotaGroupDeref(pGroup);
+        }
+      }
+    }
+    quotaLeave();
+  }
+  return rc;
+}
+
+
+/************************ I/O Method Wrappers *******************************/
+
+/* xClose requests get passed through to the original VFS.  But we
+** also have to unlink the quotaConn from the quotaFile and quotaGroup.
+** The quotaFile and/or quotaGroup are freed if they are no longer in use.
+*/
+static int quotaClose(sqlite3_file *pConn){
+  quotaConn *p = (quotaConn*)pConn;
+  quotaFile *pFile = p->pFile;
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  int rc;
+  rc = pSubOpen->pMethods->xClose(pSubOpen);
+  quotaEnter();
+  pFile->nRef--;
+  if( pFile->nRef==0 ){
+    quotaGroup *pGroup = pFile->pGroup;
+    if( pFile->deleteOnClose ) quotaRemoveFile(pFile);
+    quotaGroupDeref(pGroup);
+  }
+  quotaLeave();
+  return rc;
+}
+
+/* Pass xRead requests directory thru to the original VFS without
+** further processing.
+*/
+static int quotaRead(
+  sqlite3_file *pConn,
+  void *pBuf,
+  int iAmt,
+  sqlite3_int64 iOfst
+){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xRead(pSubOpen, pBuf, iAmt, iOfst);
+}
+
+/* Check xWrite requests to see if they expand the file.  If they do,
+** the perform a quota check before passing them through to the
+** original VFS.
+*/
+static int quotaWrite(
+  sqlite3_file *pConn,
+  const void *pBuf,
+  int iAmt,
+  sqlite3_int64 iOfst
+){
+  quotaConn *p = (quotaConn*)pConn;
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  sqlite3_int64 iEnd = iOfst+iAmt;
+  quotaGroup *pGroup;
+  quotaFile *pFile = p->pFile;
+  sqlite3_int64 szNew;
+
+  if( pFile->iSize<iEnd ){
+    pGroup = pFile->pGroup;
+    quotaEnter();
+    szNew = pGroup->iSize - pFile->iSize + iEnd;
+    if( szNew>pGroup->iLimit && pGroup->iLimit>0 ){
+      if( pGroup->xCallback ){
+        pGroup->xCallback(pFile->zFilename, &pGroup->iLimit, szNew, 
+                          pGroup->pArg);
+      }
+      if( szNew>pGroup->iLimit && pGroup->iLimit>0 ){
+        quotaLeave();
+        return SQLITE_FULL;
+      }
+    }
+    pGroup->iSize = szNew;
+    pFile->iSize = iEnd;
+    quotaLeave();
+  }
+  return pSubOpen->pMethods->xWrite(pSubOpen, pBuf, iAmt, iOfst);
+}
+
+/* Pass xTruncate requests thru to the original VFS.  If the
+** success, update the file size.
+*/
+static int quotaTruncate(sqlite3_file *pConn, sqlite3_int64 size){
+  quotaConn *p = (quotaConn*)pConn;
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  int rc = pSubOpen->pMethods->xTruncate(pSubOpen, size);
+  quotaFile *pFile = p->pFile;
+  quotaGroup *pGroup;
+  if( rc==SQLITE_OK ){
+    quotaEnter();
+    pGroup = pFile->pGroup;
+    pGroup->iSize -= pFile->iSize;
+    pFile->iSize = size;
+    pGroup->iSize += size;
+    quotaLeave();
+  }
+  return rc;
+}
+
+/* Pass xSync requests through to the original VFS without change
+*/
+static int quotaSync(sqlite3_file *pConn, int flags){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xSync(pSubOpen, flags);
+}
+
+/* Pass xFileSize requests through to the original VFS but then
+** update the quotaGroup with the new size before returning.
+*/
+static int quotaFileSize(sqlite3_file *pConn, sqlite3_int64 *pSize){
+  quotaConn *p = (quotaConn*)pConn;
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  quotaFile *pFile = p->pFile;
+  quotaGroup *pGroup;
+  sqlite3_int64 sz;
+  int rc;
+
+  rc = pSubOpen->pMethods->xFileSize(pSubOpen, &sz);
+  if( rc==SQLITE_OK ){
+    quotaEnter();
+    pGroup = pFile->pGroup;
+    pGroup->iSize -= pFile->iSize;
+    pFile->iSize = sz;
+    pGroup->iSize += sz;
+    quotaLeave();
+    *pSize = sz;
+  }
+  return rc;
+}
+
+/* Pass xLock requests through to the original VFS unchanged.
+*/
+static int quotaLock(sqlite3_file *pConn, int lock){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xLock(pSubOpen, lock);
+}
+
+/* Pass xUnlock requests through to the original VFS unchanged.
+*/
+static int quotaUnlock(sqlite3_file *pConn, int lock){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xUnlock(pSubOpen, lock);
+}
+
+/* Pass xCheckReservedLock requests through to the original VFS unchanged.
+*/
+static int quotaCheckReservedLock(sqlite3_file *pConn, int *pResOut){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xCheckReservedLock(pSubOpen, pResOut);
+}
+
+/* Pass xFileControl requests through to the original VFS unchanged.
+*/
+static int quotaFileControl(sqlite3_file *pConn, int op, void *pArg){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xFileControl(pSubOpen, op, pArg);
+}
+
+/* Pass xSectorSize requests through to the original VFS unchanged.
+*/
+static int quotaSectorSize(sqlite3_file *pConn){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xSectorSize(pSubOpen);
+}
+
+/* Pass xDeviceCharacteristics requests through to the original VFS unchanged.
+*/
+static int quotaDeviceCharacteristics(sqlite3_file *pConn){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xDeviceCharacteristics(pSubOpen);
+}
+
+/* Pass xShmMap requests through to the original VFS unchanged.
+*/
+static int quotaShmMap(
+  sqlite3_file *pConn,            /* Handle open on database file */
+  int iRegion,                    /* Region to retrieve */
+  int szRegion,                   /* Size of regions */
+  int bExtend,                    /* True to extend file if necessary */
+  void volatile **pp              /* OUT: Mapped memory */
+){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xShmMap(pSubOpen, iRegion, szRegion, bExtend, pp);
+}
+
+/* Pass xShmLock requests through to the original VFS unchanged.
+*/
+static int quotaShmLock(
+  sqlite3_file *pConn,       /* Database file holding the shared memory */
+  int ofst,                  /* First lock to acquire or release */
+  int n,                     /* Number of locks to acquire or release */
+  int flags                  /* What to do with the lock */
+){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xShmLock(pSubOpen, ofst, n, flags);
+}
+
+/* Pass xShmBarrier requests through to the original VFS unchanged.
+*/
+static void quotaShmBarrier(sqlite3_file *pConn){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  pSubOpen->pMethods->xShmBarrier(pSubOpen);
+}
+
+/* Pass xShmUnmap requests through to the original VFS unchanged.
+*/
+static int quotaShmUnmap(sqlite3_file *pConn, int deleteFlag){
+  sqlite3_file *pSubOpen = quotaSubOpen(pConn);
+  return pSubOpen->pMethods->xShmUnmap(pSubOpen, deleteFlag);
+}
+
+/************************** Public Interfaces *****************************/
+/*
+** Initialize the quota VFS shim.  Use the VFS named zOrigVfsName
+** as the VFS that does the actual work.  Use the default if
+** zOrigVfsName==NULL.  
+**
+** The quota VFS shim is named "quota".  It will become the default
+** VFS if makeDefault is non-zero.
+**
+** THIS ROUTINE IS NOT THREADSAFE.  Call this routine exactly once
+** during start-up.
+*/
+int sqlite3_quota_initialize(const char *zOrigVfsName, int makeDefault){
+  sqlite3_vfs *pOrigVfs;
+  if( gQuota.isInitialized ) return SQLITE_MISUSE;
+  pOrigVfs = sqlite3_vfs_find(zOrigVfsName);
+  if( pOrigVfs==0 ) return SQLITE_ERROR;
+  assert( pOrigVfs!=&gQuota.sThisVfs );
+  gQuota.pMutex = sqlite3_mutex_alloc(SQLITE_MUTEX_FAST);
+  if( !gQuota.pMutex ){
+    return SQLITE_NOMEM;
+  }
+  gQuota.isInitialized = 1;
+  gQuota.pOrigVfs = pOrigVfs;
+  gQuota.sThisVfs = *pOrigVfs;
+  gQuota.sThisVfs.xOpen = quotaOpen;
+  gQuota.sThisVfs.xDelete = quotaDelete;
+  gQuota.sThisVfs.szOsFile += sizeof(quotaConn);
+  gQuota.sThisVfs.zName = "quota";
+  gQuota.sIoMethodsV1.iVersion = 1;
+  gQuota.sIoMethodsV1.xClose = quotaClose;
+  gQuota.sIoMethodsV1.xRead = quotaRead;
+  gQuota.sIoMethodsV1.xWrite = quotaWrite;
+  gQuota.sIoMethodsV1.xTruncate = quotaTruncate;
+  gQuota.sIoMethodsV1.xSync = quotaSync;
+  gQuota.sIoMethodsV1.xFileSize = quotaFileSize;
+  gQuota.sIoMethodsV1.xLock = quotaLock;
+  gQuota.sIoMethodsV1.xUnlock = quotaUnlock;
+  gQuota.sIoMethodsV1.xCheckReservedLock = quotaCheckReservedLock;
+  gQuota.sIoMethodsV1.xFileControl = quotaFileControl;
+  gQuota.sIoMethodsV1.xSectorSize = quotaSectorSize;
+  gQuota.sIoMethodsV1.xDeviceCharacteristics = quotaDeviceCharacteristics;
+  gQuota.sIoMethodsV2 = gQuota.sIoMethodsV1;
+  gQuota.sIoMethodsV2.iVersion = 2;
+  gQuota.sIoMethodsV2.xShmMap = quotaShmMap;
+  gQuota.sIoMethodsV2.xShmLock = quotaShmLock;
+  gQuota.sIoMethodsV2.xShmBarrier = quotaShmBarrier;
+  gQuota.sIoMethodsV2.xShmUnmap = quotaShmUnmap;
+  sqlite3_vfs_register(&gQuota.sThisVfs, makeDefault);
+  return SQLITE_OK;
+}
+
+/*
+** Shutdown the quota system.
+**
+** All SQLite database connections must be closed before calling this
+** routine.
+**
+** THIS ROUTINE IS NOT THREADSAFE.  Call this routine exactly once while
+** shutting down in order to free all remaining quota groups.
+*/
+int sqlite3_quota_shutdown(void){
+  quotaGroup *pGroup;
+  if( gQuota.isInitialized==0 ) return SQLITE_MISUSE;
+  for(pGroup=gQuota.pGroup; pGroup; pGroup=pGroup->pNext){
+    if( quotaGroupOpenFileCount(pGroup)>0 ) return SQLITE_MISUSE;
+  }
+  while( gQuota.pGroup ){
+    pGroup = gQuota.pGroup;
+    gQuota.pGroup = pGroup->pNext;
+    pGroup->iLimit = 0;
+    assert( quotaGroupOpenFileCount(pGroup)==0 );
+    quotaGroupDeref(pGroup);
+  }
+  gQuota.isInitialized = 0;
+  sqlite3_mutex_free(gQuota.pMutex);
+  sqlite3_vfs_unregister(&gQuota.sThisVfs);
+  memset(&gQuota, 0, sizeof(gQuota));
+  return SQLITE_OK;
+}
+
+/*
+** Create or destroy a quota group.
+**
+** The quota group is defined by the zPattern.  When calling this routine
+** with a zPattern for a quota group that already exists, this routine
+** merely updates the iLimit, xCallback, and pArg values for that quota
+** group.  If zPattern is new, then a new quota group is created.
+**
+** If the iLimit for a quota group is set to zero, then the quota group
+** is disabled and will be deleted when the last database connection using
+** the quota group is closed.
+**
+** Calling this routine on a zPattern that does not exist and with a
+** zero iLimit is a no-op.
+**
+** A quota group must exist with a non-zero iLimit prior to opening
+** database connections if those connections are to participate in the
+** quota group.  Creating a quota group does not affect database connections
+** that are already open.
+*/
+int sqlite3_quota_set(
+  const char *zPattern,           /* The filename pattern */
+  sqlite3_int64 iLimit,           /* New quota to set for this quota group */
+  void (*xCallback)(              /* Callback invoked when going over quota */
+     const char *zFilename,         /* Name of file whose size increases */
+     sqlite3_int64 *piLimit,        /* IN/OUT: The current limit */
+     sqlite3_int64 iSize,           /* Total size of all files in the group */
+     void *pArg                     /* Client data */
+  ),
+  void *pArg,                     /* client data passed thru to callback */
+  void (*xDestroy)(void*)         /* Optional destructor for pArg */
+){
+  quotaGroup *pGroup;
+  quotaEnter();
+  pGroup = gQuota.pGroup;
+  while( pGroup && strcmp(pGroup->zPattern, zPattern)!=0 ){
+    pGroup = pGroup->pNext;
+  }
+  if( pGroup==0 ){
+    int nPattern = strlen(zPattern);
+    if( iLimit<=0 ){
+      quotaLeave();
+      return SQLITE_OK;
+    }
+    pGroup = (quotaGroup *)sqlite3_malloc( sizeof(*pGroup) + nPattern + 1 );
+    if( pGroup==0 ){
+      quotaLeave();
+      return SQLITE_NOMEM;
+    }
+    memset(pGroup, 0, sizeof(*pGroup));
+    pGroup->zPattern = (char*)&pGroup[1];
+    memcpy((char *)pGroup->zPattern, zPattern, nPattern+1);
+    if( gQuota.pGroup ) gQuota.pGroup->ppPrev = &pGroup->pNext;
+    pGroup->pNext = gQuota.pGroup;
+    pGroup->ppPrev = &gQuota.pGroup;
+    gQuota.pGroup = pGroup;
+  }
+  pGroup->iLimit = iLimit;
+  pGroup->xCallback = xCallback;
+  if( pGroup->xDestroy && pGroup->pArg!=pArg ){
+    pGroup->xDestroy(pGroup->pArg);
+  }
+  pGroup->pArg = pArg;
+  pGroup->xDestroy = xDestroy;
+  quotaGroupDeref(pGroup);
+  quotaLeave();
+  return SQLITE_OK;
+}
+
+/*
+** Bring the named file under quota management.  Or if it is already under
+** management, update its size.
+*/
+int sqlite3_quota_file(const char *zFilename){
+  char *zFull;
+  sqlite3_file *fd;
+  int rc;
+  int outFlags = 0;
+  sqlite3_int64 iSize;
+  fd = sqlite3_malloc(gQuota.sThisVfs.szOsFile + gQuota.sThisVfs.mxPathname+1);
+  if( fd==0 ) return SQLITE_NOMEM;
+  zFull = gQuota.sThisVfs.szOsFile + (char*)fd;
+  rc = gQuota.pOrigVfs->xFullPathname(gQuota.pOrigVfs, zFilename,
+                                      gQuota.sThisVfs.mxPathname+1, zFull);
+  if( rc==SQLITE_OK ){
+    rc = quotaOpen(&gQuota.sThisVfs, zFull, fd, 
+                   SQLITE_OPEN_READONLY | SQLITE_OPEN_MAIN_DB, &outFlags);
+  }
+  if( rc==SQLITE_OK ){
+    fd->pMethods->xFileSize(fd, &iSize);
+    fd->pMethods->xClose(fd);
+  }else if( rc==SQLITE_CANTOPEN ){
+    quotaGroup *pGroup;
+    quotaFile *pFile;
+    quotaEnter();
+    pGroup = quotaGroupFind(zFull);
+    if( pGroup ){
+      pFile = quotaFindFile(pGroup, zFull);
+      if( pFile ) quotaRemoveFile(pFile);
+    }
+    quotaLeave();
+  }
+  sqlite3_free(fd);
+  return rc;
+}
+
+  
+/***************************** Test Code ***********************************/
+#ifdef SQLITE_TEST
+#include <tcl.h>
+
+/*
+** Argument passed to a TCL quota-over-limit callback.
+*/
+typedef struct TclQuotaCallback TclQuotaCallback;
+struct TclQuotaCallback {
+  Tcl_Interp *interp;    /* Interpreter in which to run the script */
+  Tcl_Obj *pScript;      /* Script to be run */
+};
+
+extern const char *sqlite3TestErrorName(int);
+
+
+/*
+** This is the callback from a quota-over-limit.
+*/
+static void tclQuotaCallback(
+  const char *zFilename,          /* Name of file whose size increases */
+  sqlite3_int64 *piLimit,         /* IN/OUT: The current limit */
+  sqlite3_int64 iSize,            /* Total size of all files in the group */
+  void *pArg                      /* Client data */
+){
+  TclQuotaCallback *p;            /* Callback script object */
+  Tcl_Obj *pEval;                 /* Script to evaluate */
+  Tcl_Obj *pVarname;              /* Name of variable to pass as 2nd arg */
+  unsigned int rnd;               /* Random part of pVarname */
+  int rc;                         /* Tcl error code */
+
+  p = (TclQuotaCallback *)pArg;
+  if( p==0 ) return;
+
+  pVarname = Tcl_NewStringObj("::piLimit_", -1);
+  Tcl_IncrRefCount(pVarname);
+  sqlite3_randomness(sizeof(rnd), (void *)&rnd);
+  Tcl_AppendObjToObj(pVarname, Tcl_NewIntObj((int)(rnd&0x7FFFFFFF)));
+  Tcl_ObjSetVar2(p->interp, pVarname, 0, Tcl_NewWideIntObj(*piLimit), 0);
+
+  pEval = Tcl_DuplicateObj(p->pScript);
+  Tcl_IncrRefCount(pEval);
+  Tcl_ListObjAppendElement(0, pEval, Tcl_NewStringObj(zFilename, -1));
+  Tcl_ListObjAppendElement(0, pEval, pVarname);
+  Tcl_ListObjAppendElement(0, pEval, Tcl_NewWideIntObj(iSize));
+  rc = Tcl_EvalObjEx(p->interp, pEval, TCL_EVAL_GLOBAL);
+
+  if( rc==TCL_OK ){
+    Tcl_Obj *pLimit = Tcl_ObjGetVar2(p->interp, pVarname, 0, 0);
+    rc = Tcl_GetWideIntFromObj(p->interp, pLimit, piLimit);
+    Tcl_UnsetVar(p->interp, Tcl_GetString(pVarname), 0);
+  }
+
+  Tcl_DecrRefCount(pEval);
+  Tcl_DecrRefCount(pVarname);
+  if( rc!=TCL_OK ) Tcl_BackgroundError(p->interp);
+}
+
+/*
+** Destructor for a TCL quota-over-limit callback.
+*/
+static void tclCallbackDestructor(void *pObj){
+  TclQuotaCallback *p = (TclQuotaCallback*)pObj;
+  if( p ){
+    Tcl_DecrRefCount(p->pScript);
+    sqlite3_free((char *)p);
+  }
+}
+
+/*
+** tclcmd: sqlite3_quota_initialize NAME MAKEDEFAULT
+*/
+static int test_quota_initialize(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  const char *zName;              /* Name of new quota VFS */
+  int makeDefault;                /* True to make the new VFS the default */
+  int rc;                         /* Value returned by quota_initialize() */
+
+  /* Process arguments */
+  if( objc!=3 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "NAME MAKEDEFAULT");
+    return TCL_ERROR;
+  }
+  zName = Tcl_GetString(objv[1]);
+  if( Tcl_GetBooleanFromObj(interp, objv[2], &makeDefault) ) return TCL_ERROR;
+  if( zName[0]=='\0' ) zName = 0;
+
+  /* Call sqlite3_quota_initialize() */
+  rc = sqlite3_quota_initialize(zName, makeDefault);
+  Tcl_SetResult(interp, (char *)sqlite3TestErrorName(rc), TCL_STATIC);
+
+  return TCL_OK;
+}
+
+/*
+** tclcmd: sqlite3_quota_shutdown
+*/
+static int test_quota_shutdown(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  int rc;                         /* Value returned by quota_shutdown() */
+
+  if( objc!=1 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "");
+    return TCL_ERROR;
+  }
+
+  /* Call sqlite3_quota_shutdown() */
+  rc = sqlite3_quota_shutdown();
+  Tcl_SetResult(interp, (char *)sqlite3TestErrorName(rc), TCL_STATIC);
+
+  return TCL_OK;
+}
+
+/*
+** tclcmd: sqlite3_quota_set PATTERN LIMIT SCRIPT
+*/
+static int test_quota_set(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  const char *zPattern;           /* File pattern to configure */
+  sqlite3_int64 iLimit;           /* Initial quota in bytes */
+  Tcl_Obj *pScript;               /* Tcl script to invoke to increase quota */
+  int rc;                         /* Value returned by quota_set() */
+  TclQuotaCallback *p;            /* Callback object */
+  int nScript;                    /* Length of callback script */
+  void (*xDestroy)(void*);        /* Optional destructor for pArg */
+  void (*xCallback)(const char *, sqlite3_int64 *, sqlite3_int64, void *);
+
+  /* Process arguments */
+  if( objc!=4 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "PATTERN LIMIT SCRIPT");
+    return TCL_ERROR;
+  }
+  zPattern = Tcl_GetString(objv[1]);
+  if( Tcl_GetWideIntFromObj(interp, objv[2], &iLimit) ) return TCL_ERROR;
+  pScript = objv[3];
+  Tcl_GetStringFromObj(pScript, &nScript);
+
+  if( nScript>0 ){
+    /* Allocate a TclQuotaCallback object */
+    p = (TclQuotaCallback *)sqlite3_malloc(sizeof(TclQuotaCallback));
+    if( !p ){
+      Tcl_SetResult(interp, (char *)"SQLITE_NOMEM", TCL_STATIC);
+      return TCL_OK;
+    }
+    memset(p, 0, sizeof(TclQuotaCallback));
+    p->interp = interp;
+    Tcl_IncrRefCount(pScript);
+    p->pScript = pScript;
+    xDestroy = tclCallbackDestructor;
+    xCallback = tclQuotaCallback;
+  }else{
+    p = 0;
+    xDestroy = 0;
+    xCallback = 0;
+  }
+
+  /* Invoke sqlite3_quota_set() */
+  rc = sqlite3_quota_set(zPattern, iLimit, xCallback, (void*)p, xDestroy);
+
+  Tcl_SetResult(interp, (char *)sqlite3TestErrorName(rc), TCL_STATIC);
+  return TCL_OK;
+}
+
+/*
+** tclcmd: sqlite3_quota_file FILENAME
+*/
+static int test_quota_file(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  const char *zFilename;          /* File pattern to configure */
+  int rc;                         /* Value returned by quota_file() */
+
+  /* Process arguments */
+  if( objc!=2 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "FILENAME");
+    return TCL_ERROR;
+  }
+  zFilename = Tcl_GetString(objv[1]);
+
+  /* Invoke sqlite3_quota_file() */
+  rc = sqlite3_quota_file(zFilename);
+
+  Tcl_SetResult(interp, (char *)sqlite3TestErrorName(rc), TCL_STATIC);
+  return TCL_OK;
+}
+
+/*
+** tclcmd:  sqlite3_quota_dump
+*/
+static int test_quota_dump(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  Tcl_Obj *pResult;
+  Tcl_Obj *pGroupTerm;
+  Tcl_Obj *pFileTerm;
+  quotaGroup *pGroup;
+  quotaFile *pFile;
+
+  pResult = Tcl_NewObj();
+  quotaEnter();
+  for(pGroup=gQuota.pGroup; pGroup; pGroup=pGroup->pNext){
+    pGroupTerm = Tcl_NewObj();
+    Tcl_ListObjAppendElement(interp, pGroupTerm,
+          Tcl_NewStringObj(pGroup->zPattern, -1));
+    Tcl_ListObjAppendElement(interp, pGroupTerm,
+          Tcl_NewWideIntObj(pGroup->iLimit));
+    Tcl_ListObjAppendElement(interp, pGroupTerm,
+          Tcl_NewWideIntObj(pGroup->iSize));
+    for(pFile=pGroup->pFiles; pFile; pFile=pFile->pNext){
+      pFileTerm = Tcl_NewObj();
+      Tcl_ListObjAppendElement(interp, pFileTerm,
+            Tcl_NewStringObj(pFile->zFilename, -1));
+      Tcl_ListObjAppendElement(interp, pFileTerm,
+            Tcl_NewWideIntObj(pFile->iSize));
+      Tcl_ListObjAppendElement(interp, pFileTerm,
+            Tcl_NewWideIntObj(pFile->nRef));
+      Tcl_ListObjAppendElement(interp, pFileTerm,
+            Tcl_NewWideIntObj(pFile->deleteOnClose));
+      Tcl_ListObjAppendElement(interp, pGroupTerm, pFileTerm);
+    }
+    Tcl_ListObjAppendElement(interp, pResult, pGroupTerm);
+  }
+  quotaLeave();
+  Tcl_SetObjResult(interp, pResult);
+  return TCL_OK;
+}
+
+/*
+** This routine registers the custom TCL commands defined in this
+** module.  This should be the only procedure visible from outside
+** of this module.
+*/
+int Sqlitequota_Init(Tcl_Interp *interp){
+  static struct {
+     char *zName;
+     Tcl_ObjCmdProc *xProc;
+  } aCmd[] = {
+    { "sqlite3_quota_initialize", test_quota_initialize },
+    { "sqlite3_quota_shutdown", test_quota_shutdown },
+    { "sqlite3_quota_set", test_quota_set },
+    { "sqlite3_quota_file", test_quota_file },
+    { "sqlite3_quota_dump", test_quota_dump },
+  };
+  int i;
+
+  for(i=0; i<sizeof(aCmd)/sizeof(aCmd[0]); i++){
+    Tcl_CreateObjCommand(interp, aCmd[i].zName, aCmd[i].xProc, 0, 0);
+  }
+
+  return TCL_OK;
+}
+#endif