persistentstorage/sqlite3api/TEST/SRC/test_osinst.c
changeset 0 08ec8eefde2f
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/persistentstorage/sqlite3api/TEST/SRC/test_osinst.c	Fri Jan 22 11:06:30 2010 +0200
@@ -0,0 +1,1069 @@
+/*
+** 2008 April 10
+**
+** 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 the implementation of an SQLite vfs wrapper that
+** adds instrumentation to all vfs and file methods. C and Tcl interfaces
+** are provided to control the instrumentation.
+**
+** $Id: test_osinst.c,v 1.18 2008/07/25 13:32:45 drh Exp $
+*/
+
+#ifdef SQLITE_ENABLE_INSTVFS
+/*
+** C interface:
+**
+**   sqlite3_instvfs_create()
+**   sqlite3_instvfs_destroy()
+**   sqlite3_instvfs_configure()
+**
+**   sqlite3_instvfs_reset()
+**   sqlite3_instvfs_get()
+**
+**   sqlite3_instvfs_binarylog
+**   sqlite3_instvfs_binarylog_marker
+**
+** Tcl interface (omitted if SQLITE_TEST is not set):
+** 
+**   sqlite3_instvfs create NAME ?PARENT?
+**
+**       Create and register new vfs called $NAME, which is a wrapper around
+**       the existing vfs $PARENT. If the PARENT argument is omitted, the
+**       new vfs is a wrapper around the current default vfs.
+**
+**   sqlite3_instvfs destroy NAME
+**
+**       Deregister and destroy the vfs named $NAME, which must have been
+**       created by an earlier invocation of [sqlite3_instvfs create].
+**
+**   sqlite3_instvfs configure NAME SCRIPT
+**
+**       Configure the callback script for the vfs $NAME, which much have
+**       been created by an earlier invocation of [sqlite3_instvfs create].
+**       After a callback script has been configured, it is invoked each
+**       time a vfs or file method is called by SQLite. Before invoking
+**       the callback script, five arguments are appended to it:
+**
+**         * The name of the invoked method - i.e. "xRead".
+**
+**         * The time consumed by the method call as measured by 
+**           sqlite3Hwtime() (an integer value)
+**
+**         * A string value with a different meaning for different calls. 
+**           For file methods, the name of the file being operated on. For
+**           other methods it is the filename argument, if any.
+**
+**         * A 32-bit integer value with a call-specific meaning.
+**
+**         * A 64-bit integer value. For xRead() and xWrite() calls this
+**           is the file offset being written to or read from. Unused by
+**           all other calls.
+**
+**   sqlite3_instvfs reset NAME
+**
+**       Zero the internal event counters associated with vfs $NAME, 
+**       which must have been created by an earlier invocation of 
+**       [sqlite3_instvfs create].
+**
+**   sqlite3_instvfs report NAME
+**
+**       Return the values of the internal event counters associated 
+**       with vfs $NAME. The report format is a list with one element
+**       for each method call (xWrite, xRead etc.). Each element is
+**       itself a list with three elements:
+**
+**         * The name of the method call - i.e. "xWrite",
+**         * The total number of calls to the method (an integer).
+**         * The aggregate time consumed by all calls to the method as
+**           measured by sqlite3Hwtime() (an integer).
+*/
+
+#include "sqlite3.h"
+#include <string.h>
+#include <assert.h>
+
+/*
+** Maximum pathname length supported by the inst backend.
+*/
+#define INST_MAX_PATHNAME 512
+
+
+/* File methods */
+/* Vfs methods */
+#define OS_ACCESS            1
+#define OS_CHECKRESERVEDLOCK 2
+#define OS_CLOSE             3
+#define OS_CURRENTTIME       4
+#define OS_DELETE            5
+#define OS_DEVCHAR           6
+#define OS_FILECONTROL       7
+#define OS_FILESIZE          8
+#define OS_FULLPATHNAME      9
+#define OS_LOCK              11
+#define OS_OPEN              12
+#define OS_RANDOMNESS        13
+#define OS_READ              14 
+#define OS_SECTORSIZE        15
+#define OS_SLEEP             16
+#define OS_SYNC              17
+#define OS_TRUNCATE          18
+#define OS_UNLOCK            19
+#define OS_WRITE             20
+
+#define OS_NUMEVENTS         21
+
+#define BINARYLOG_STRING     30
+#define BINARYLOG_MARKER     31
+
+#define BINARYLOG_PREPARE_V2 64
+#define BINARYLOG_STEP       65
+#define BINARYLOG_FINALIZE   66
+
+struct InstVfs {
+  sqlite3_vfs base;
+  sqlite3_vfs *pVfs;
+
+  void *pClient;
+  void (*xDel)(void *);
+  void (*xCall)(void *, int, int, sqlite3_int64, int, const char *, int, int, sqlite3_int64);
+
+  /* Counters */
+  sqlite3_int64 aTime[OS_NUMEVENTS];
+  int aCount[OS_NUMEVENTS];
+
+  int iNextFileId;
+};
+typedef struct InstVfs InstVfs;
+
+#define REALVFS(p) (((InstVfs *)(p))->pVfs)
+
+typedef struct inst_file inst_file;
+struct inst_file {
+  sqlite3_file base;
+  sqlite3_file *pReal;
+  InstVfs *pInstVfs;
+  const char *zName;
+  int iFileId;               /* File id number */
+  int flags;
+};
+
+/*
+** Method declarations for inst_file.
+*/
+static int instClose(sqlite3_file*);
+static int instRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int instWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
+static int instTruncate(sqlite3_file*, sqlite3_int64 size);
+static int instSync(sqlite3_file*, int flags);
+static int instFileSize(sqlite3_file*, sqlite3_int64 *pSize);
+static int instLock(sqlite3_file*, int);
+static int instUnlock(sqlite3_file*, int);
+static int instCheckReservedLock(sqlite3_file*, int *pResOut);
+static int instFileControl(sqlite3_file*, int op, void *pArg);
+static int instSectorSize(sqlite3_file*);
+static int instDeviceCharacteristics(sqlite3_file*);
+
+/*
+** Method declarations for inst_vfs.
+*/
+static int instOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
+static int instDelete(sqlite3_vfs*, const char *zName, int syncDir);
+static int instAccess(sqlite3_vfs*, const char *zName, int flags, int *);
+static int instFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
+static void *instDlOpen(sqlite3_vfs*, const char *zFilename);
+static void instDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
+static void *instDlSym(sqlite3_vfs*,void*, const char *zSymbol);
+static void instDlClose(sqlite3_vfs*, void*);
+static int instRandomness(sqlite3_vfs*, int nByte, char *zOut);
+static int instSleep(sqlite3_vfs*, int microseconds);
+static int instCurrentTime(sqlite3_vfs*, double*);
+
+static void binarylog_blob(sqlite3_vfs *, const char *, int, int); 
+
+static sqlite3_vfs inst_vfs = {
+  1,                      /* iVersion */
+  sizeof(inst_file),      /* szOsFile */
+  INST_MAX_PATHNAME,      /* mxPathname */
+  0,                      /* pNext */
+  0,                      /* zName */
+  0,                      /* pAppData */
+  instOpen,               /* xOpen */
+  instDelete,             /* xDelete */
+  instAccess,             /* xAccess */
+  instFullPathname,       /* xFullPathname */
+  instDlOpen,             /* xDlOpen */
+  instDlError,            /* xDlError */
+  instDlSym,              /* xDlSym */
+  instDlClose,            /* xDlClose */
+  instRandomness,         /* xRandomness */
+  instSleep,              /* xSleep */
+  instCurrentTime         /* xCurrentTime */
+};
+
+static sqlite3_io_methods inst_io_methods = {
+  1,                            /* iVersion */
+  instClose,                      /* xClose */
+  instRead,                       /* xRead */
+  instWrite,                      /* xWrite */
+  instTruncate,                   /* xTruncate */
+  instSync,                       /* xSync */
+  instFileSize,                   /* xFileSize */
+  instLock,                       /* xLock */
+  instUnlock,                     /* xUnlock */
+  instCheckReservedLock,          /* xCheckReservedLock */
+  instFileControl,                /* xFileControl */
+  instSectorSize,                 /* xSectorSize */
+  instDeviceCharacteristics       /* xDeviceCharacteristics */
+};
+
+/* 
+** hwtime.h contains inline assembler code for implementing 
+** high-performance timing routines.
+*/
+#include "hwtime.h"
+
+#define OS_TIME_IO(eEvent, A, B, Call) {     \
+  inst_file *p = (inst_file *)pFile;         \
+  InstVfs *pInstVfs = p->pInstVfs;           \
+  int rc;                                    \
+  sqlite_uint64 t = sqlite3Hwtime();         \
+  rc = Call;                                 \
+  t = sqlite3Hwtime() - t;                   \
+  pInstVfs->aTime[eEvent] += t;              \
+  pInstVfs->aCount[eEvent] += 1;             \
+  if( pInstVfs->xCall ){                     \
+    pInstVfs->xCall(                         \
+      pInstVfs->pClient,eEvent,p->iFileId,t,rc,p->zName,p->flags,A,B  \
+    );                                       \
+  }                                          \
+  return rc;                                 \
+}
+
+#define OS_TIME_VFS(eEvent, Z, flags, A, B, Call) {      \
+  InstVfs *pInstVfs = (InstVfs *)pVfs;   \
+  int rc;                                \
+  sqlite_uint64 t = sqlite3Hwtime();     \
+  rc = Call;                             \
+  t = sqlite3Hwtime() - t;               \
+  pInstVfs->aTime[eEvent] += t;          \
+  pInstVfs->aCount[eEvent] += 1;         \
+  if( pInstVfs->xCall ){                 \
+    pInstVfs->xCall(pInstVfs->pClient,eEvent,0, t, rc, Z, flags, A, B); \
+  }                                      \
+  return rc;                             \
+}
+
+/*
+** Close an inst-file.
+*/
+static int instClose(sqlite3_file *pFile){
+  OS_TIME_IO(OS_CLOSE, 0, 0, 
+    (p->pReal->pMethods ? p->pReal->pMethods->xClose(p->pReal) : SQLITE_OK)
+  );
+}
+
+/*
+** Read data from an inst-file.
+*/
+static int instRead(
+  sqlite3_file *pFile, 
+  void *zBuf, 
+  int iAmt, 
+  sqlite_int64 iOfst
+){
+  sqlite3_vfs *pVfs = (sqlite3_vfs *)(((inst_file *)pFile)->pInstVfs);
+  OS_TIME_IO(OS_READ, iAmt, (binarylog_blob(pVfs, zBuf, iAmt, 1), iOfst), 
+      p->pReal->pMethods->xRead(p->pReal, zBuf, iAmt, iOfst)
+  );
+}
+
+/*
+** Write data to an inst-file.
+*/
+static int instWrite(
+  sqlite3_file *pFile,
+  const void *z,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  sqlite3_vfs *pVfs = (sqlite3_vfs *)(((inst_file *)pFile)->pInstVfs);
+  binarylog_blob(pVfs, z, iAmt, 1);
+  OS_TIME_IO(OS_WRITE, iAmt, iOfst, 
+      p->pReal->pMethods->xWrite(p->pReal, z, iAmt, iOfst)
+  );
+}
+
+/*
+** Truncate an inst-file.
+*/
+static int instTruncate(sqlite3_file *pFile, sqlite_int64 size){
+  OS_TIME_IO(OS_TRUNCATE, 0, (int)size, 
+    p->pReal->pMethods->xTruncate(p->pReal, size)
+  );
+}
+
+/*
+** Sync an inst-file.
+*/
+static int instSync(sqlite3_file *pFile, int flags){
+  OS_TIME_IO(OS_SYNC, flags, 0, p->pReal->pMethods->xSync(p->pReal, flags));
+}
+
+/*
+** Return the current file-size of an inst-file.
+*/
+static int instFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
+  OS_TIME_IO(OS_FILESIZE, (int)(*pSize), 0, 
+    p->pReal->pMethods->xFileSize(p->pReal, pSize)
+  );
+}
+
+/*
+** Lock an inst-file.
+*/
+static int instLock(sqlite3_file *pFile, int eLock){
+  OS_TIME_IO(OS_LOCK, eLock, 0, p->pReal->pMethods->xLock(p->pReal, eLock));
+}
+
+/*
+** Unlock an inst-file.
+*/
+static int instUnlock(sqlite3_file *pFile, int eLock){
+  OS_TIME_IO(OS_UNLOCK, eLock, 0, p->pReal->pMethods->xUnlock(p->pReal, eLock));
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on an inst-file.
+*/
+static int instCheckReservedLock(sqlite3_file *pFile, int *pResOut){
+  OS_TIME_IO(OS_CHECKRESERVEDLOCK, 0, 0, 
+      p->pReal->pMethods->xCheckReservedLock(p->pReal, pResOut)
+  );
+}
+
+/*
+** File control method. For custom operations on an inst-file.
+*/
+static int instFileControl(sqlite3_file *pFile, int op, void *pArg){
+  OS_TIME_IO(OS_FILECONTROL, 0, 0, p->pReal->pMethods->xFileControl(p->pReal, op, pArg));
+}
+
+/*
+** Return the sector-size in bytes for an inst-file.
+*/
+static int instSectorSize(sqlite3_file *pFile){
+  OS_TIME_IO(OS_SECTORSIZE, 0, 0, p->pReal->pMethods->xSectorSize(p->pReal));
+}
+
+/*
+** Return the device characteristic flags supported by an inst-file.
+*/
+static int instDeviceCharacteristics(sqlite3_file *pFile){
+  OS_TIME_IO(OS_DEVCHAR, 0, 0, p->pReal->pMethods->xDeviceCharacteristics(p->pReal));
+}
+
+/*
+** Open an inst file handle.
+*/
+static int instOpen(
+  sqlite3_vfs *pVfs,
+  const char *zName,
+  sqlite3_file *pFile,
+  int flags,
+  int *pOutFlags
+){
+  inst_file *p = (inst_file *)pFile;
+  pFile->pMethods = &inst_io_methods;
+  p->pReal = (sqlite3_file *)&p[1];
+  p->pInstVfs = (InstVfs *)pVfs;
+  p->zName = zName;
+  p->flags = flags;
+  p->iFileId = ++p->pInstVfs->iNextFileId;
+
+  binarylog_blob(pVfs, zName, -1, 0);
+  OS_TIME_VFS(OS_OPEN, zName, flags, p->iFileId, 0,
+    REALVFS(pVfs)->xOpen(REALVFS(pVfs), zName, p->pReal, flags, pOutFlags)
+  );
+}
+
+/*
+** Delete the file located at zPath. If the dirSync argument is true,
+** ensure the file-system modifications are synced to disk before
+** returning.
+*/
+static int instDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  binarylog_blob(pVfs, zPath, -1, 0);
+  OS_TIME_VFS(OS_DELETE, zPath, 0, dirSync, 0,
+    REALVFS(pVfs)->xDelete(REALVFS(pVfs), zPath, dirSync) 
+  );
+}
+
+/*
+** Test for access permissions. Return true if the requested permission
+** is available, or false otherwise.
+*/
+static int instAccess(
+  sqlite3_vfs *pVfs, 
+  const char *zPath, 
+  int flags, 
+  int *pResOut
+){
+  binarylog_blob(pVfs, zPath, -1, 0);
+  OS_TIME_VFS(OS_ACCESS, zPath, 0, flags, *pResOut, 
+    REALVFS(pVfs)->xAccess(REALVFS(pVfs), zPath, flags, pResOut) 
+  );
+}
+
+/*
+** Populate buffer zOut with the full canonical pathname corresponding
+** to the pathname in zPath. zOut is guaranteed to point to a buffer
+** of at least (INST_MAX_PATHNAME+1) bytes.
+*/
+static int instFullPathname(
+  sqlite3_vfs *pVfs, 
+  const char *zPath, 
+  int nOut, 
+  char *zOut
+){
+  OS_TIME_VFS( OS_FULLPATHNAME, zPath, 0, 0, 0,
+    REALVFS(pVfs)->xFullPathname(REALVFS(pVfs), zPath, nOut, zOut);
+  );
+}
+
+/*
+** Open the dynamic library located at zPath and return a handle.
+*/
+static void *instDlOpen(sqlite3_vfs *pVfs, const char *zPath){
+  return REALVFS(pVfs)->xDlOpen(REALVFS(pVfs), zPath);
+}
+
+/*
+** Populate the buffer zErrMsg (size nByte bytes) with a human readable
+** utf-8 string describing the most recent error encountered associated 
+** with dynamic libraries.
+*/
+static void instDlError(sqlite3_vfs *pVfs, int nByte, char *zErrMsg){
+  REALVFS(pVfs)->xDlError(REALVFS(pVfs), nByte, zErrMsg);
+}
+
+/*
+** Return a pointer to the symbol zSymbol in the dynamic library pHandle.
+*/
+static void *instDlSym(sqlite3_vfs *pVfs, void *pHandle, const char *zSymbol){
+  return REALVFS(pVfs)->xDlSym(REALVFS(pVfs), pHandle, zSymbol);
+}
+
+/*
+** Close the dynamic library handle pHandle.
+*/
+static void instDlClose(sqlite3_vfs *pVfs, void *pHandle){
+  REALVFS(pVfs)->xDlClose(REALVFS(pVfs), pHandle);
+}
+
+/*
+** Populate the buffer pointed to by zBufOut with nByte bytes of 
+** random data.
+*/
+static int instRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  OS_TIME_VFS( OS_RANDOMNESS, 0, 0, nByte, 0,
+    REALVFS(pVfs)->xRandomness(REALVFS(pVfs), nByte, zBufOut);
+  );
+}
+
+/*
+** Sleep for nMicro microseconds. Return the number of microseconds 
+** actually slept.
+*/
+static int instSleep(sqlite3_vfs *pVfs, int nMicro){
+  OS_TIME_VFS( OS_SLEEP, 0, 0, nMicro, 0, 
+    REALVFS(pVfs)->xSleep(REALVFS(pVfs), nMicro) 
+  );
+}
+
+/*
+** Return the current time as a Julian Day number in *pTimeOut.
+*/
+static int instCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+  OS_TIME_VFS( OS_CURRENTTIME, 0, 0, 0, 0,
+    REALVFS(pVfs)->xCurrentTime(REALVFS(pVfs), pTimeOut) 
+  );
+}
+
+sqlite3_vfs *sqlite3_instvfs_create(const char *zName, const char *zParent){
+  int nByte;
+  InstVfs *p;
+  sqlite3_vfs *pParent;
+
+  pParent = sqlite3_vfs_find(zParent);
+  if( !pParent ){
+    return 0;
+  }
+
+  nByte = strlen(zName) + 1 + sizeof(InstVfs);
+  p = (InstVfs *)sqlite3_malloc(nByte);
+  if( p ){
+    char *zCopy = (char *)&p[1];
+    memset(p, 0, nByte);
+    memcpy(p, &inst_vfs, sizeof(sqlite3_vfs));
+    p->pVfs = pParent;
+    memcpy(zCopy, zName, strlen(zName));
+    p->base.zName = (const char *)zCopy;
+    p->base.szOsFile += pParent->szOsFile;
+    sqlite3_vfs_register((sqlite3_vfs *)p, 0);
+  }
+
+  return (sqlite3_vfs *)p;
+}
+
+void sqlite3_instvfs_configure(
+  sqlite3_vfs *pVfs,
+  void (*xCall)(
+      void*, 
+      int,                           /* File id */
+      int,                           /* Event code */
+      sqlite3_int64, 
+      int,                           /* Return code */
+      const char*,                   /* File name */
+      int, 
+      int, 
+      sqlite3_int64
+  ),
+  void *pClient,
+  void (*xDel)(void *)
+){
+  InstVfs *p = (InstVfs *)pVfs;
+  assert( pVfs->xOpen==instOpen );
+  if( p->xDel ){
+    p->xDel(p->pClient);
+  }
+  p->xCall = xCall;
+  p->xDel = xDel;
+  p->pClient = pClient;
+}
+
+void sqlite3_instvfs_destroy(sqlite3_vfs *pVfs){
+  if( pVfs ){
+    sqlite3_vfs_unregister(pVfs);
+    sqlite3_instvfs_configure(pVfs, 0, 0, 0);
+    sqlite3_free(pVfs);
+  }
+}
+
+void sqlite3_instvfs_reset(sqlite3_vfs *pVfs){
+  InstVfs *p = (InstVfs *)pVfs;
+  assert( pVfs->xOpen==instOpen );
+  memset(p->aTime, 0, sizeof(sqlite3_int64)*OS_NUMEVENTS);
+  memset(p->aCount, 0, sizeof(int)*OS_NUMEVENTS);
+}
+
+const char *sqlite3_instvfs_name(int eEvent){
+  const char *zEvent = 0;
+
+  switch( eEvent ){
+    case OS_CLOSE:             zEvent = "xClose"; break;
+    case OS_READ:              zEvent = "xRead"; break;
+    case OS_WRITE:             zEvent = "xWrite"; break;
+    case OS_TRUNCATE:          zEvent = "xTruncate"; break;
+    case OS_SYNC:              zEvent = "xSync"; break;
+    case OS_FILESIZE:          zEvent = "xFilesize"; break;
+    case OS_LOCK:              zEvent = "xLock"; break;
+    case OS_UNLOCK:            zEvent = "xUnlock"; break;
+    case OS_CHECKRESERVEDLOCK: zEvent = "xCheckReservedLock"; break;
+    case OS_FILECONTROL:       zEvent = "xFileControl"; break;
+    case OS_SECTORSIZE:        zEvent = "xSectorSize"; break;
+    case OS_DEVCHAR:           zEvent = "xDeviceCharacteristics"; break;
+    case OS_OPEN:              zEvent = "xOpen"; break;
+    case OS_DELETE:            zEvent = "xDelete"; break;
+    case OS_ACCESS:            zEvent = "xAccess"; break;
+    case OS_FULLPATHNAME:      zEvent = "xFullPathname"; break;
+    case OS_RANDOMNESS:        zEvent = "xRandomness"; break;
+    case OS_SLEEP:             zEvent = "xSleep"; break;
+    case OS_CURRENTTIME:       zEvent = "xCurrentTime"; break;
+  }
+
+  return zEvent;
+}
+
+void sqlite3_instvfs_get(
+  sqlite3_vfs *pVfs, 
+  int eEvent, 
+  const char **pzEvent, 
+  sqlite3_int64 *pnClick, 
+  int *pnCall
+){
+  InstVfs *p = (InstVfs *)pVfs;
+  assert( pVfs->xOpen==instOpen );
+  if( eEvent<1 || eEvent>=OS_NUMEVENTS ){
+    *pzEvent = 0;
+    *pnClick = 0;
+    *pnCall = 0;
+    return;
+  }
+
+  *pzEvent = sqlite3_instvfs_name(eEvent);
+  *pnClick = p->aTime[eEvent];
+  *pnCall = p->aCount[eEvent];
+}
+
+#define BINARYLOG_BUFFERSIZE 8192
+
+struct InstVfsBinaryLog {
+  int nBuf;
+  char *zBuf;
+  sqlite3_int64 iOffset;
+  int log_data;
+  sqlite3_file *pOut;
+  char *zOut;                       /* Log file name */
+};
+typedef struct InstVfsBinaryLog InstVfsBinaryLog;
+
+static void put32bits(unsigned char *p, unsigned int v){
+  p[0] = v>>24;
+  p[1] = v>>16;
+  p[2] = v>>8;
+  p[3] = v;
+}
+
+static void binarylog_flush(InstVfsBinaryLog *pLog){
+  sqlite3_file *pFile = pLog->pOut;
+
+#ifdef SQLITE_TEST
+  extern int sqlite3_io_error_pending;
+  extern int sqlite3_io_error_persist;
+  extern int sqlite3_diskfull_pending;
+
+  int pending = sqlite3_io_error_pending;
+  int persist = sqlite3_io_error_persist;
+  int diskfull = sqlite3_diskfull_pending;
+
+  sqlite3_io_error_pending = 0;
+  sqlite3_io_error_persist = 0;
+  sqlite3_diskfull_pending = 0;
+#endif
+
+  pFile->pMethods->xWrite(pFile, pLog->zBuf, pLog->nBuf, pLog->iOffset);
+  pLog->iOffset += pLog->nBuf;
+  pLog->nBuf = 0;
+
+#ifdef SQLITE_TEST
+  sqlite3_io_error_pending = pending;
+  sqlite3_io_error_persist = persist;
+  sqlite3_diskfull_pending = diskfull;
+#endif
+}
+
+static void binarylog_xcall(
+  void *p,
+  int eEvent,
+  int iFileId,
+  sqlite3_int64 nClick,
+  int return_code,
+  const char *zName,
+  int flags,
+  int nByte,
+  sqlite3_int64 iOffset
+){
+  InstVfsBinaryLog *pLog = (InstVfsBinaryLog *)p;
+  unsigned char *zRec;
+  if( (28+pLog->nBuf)>BINARYLOG_BUFFERSIZE ){
+    binarylog_flush(pLog);
+  }
+  zRec = (unsigned char *)&pLog->zBuf[pLog->nBuf];
+  put32bits(&zRec[0], eEvent);
+  put32bits(&zRec[4], (int)iFileId);
+  put32bits(&zRec[8], (int)nClick);
+  put32bits(&zRec[12], return_code);
+  put32bits(&zRec[16], flags);
+  put32bits(&zRec[20], nByte);
+  put32bits(&zRec[24], (int)iOffset);
+  pLog->nBuf += 28;
+}
+
+static void binarylog_xdel(void *p){
+  /* Close the log file and free the memory allocated for the 
+  ** InstVfsBinaryLog structure.
+  */
+  InstVfsBinaryLog *pLog = (InstVfsBinaryLog *)p;
+  sqlite3_file *pFile = pLog->pOut;
+  if( pLog->nBuf ){
+    binarylog_flush(pLog);
+  }
+  pFile->pMethods->xClose(pFile);
+  sqlite3_free(pLog->pOut);
+  sqlite3_free(pLog->zBuf);
+  sqlite3_free(pLog);
+}
+
+static void binarylog_blob(
+  sqlite3_vfs *pVfs,
+  const char *zBlob,
+  int nBlob,
+  int isBinary
+){
+  InstVfsBinaryLog *pLog;
+  InstVfs *pInstVfs = (InstVfs *)pVfs;
+
+  if( pVfs->xOpen!=instOpen || pInstVfs->xCall!=binarylog_xcall ){
+    return;
+  }
+  pLog = (InstVfsBinaryLog *)pInstVfs->pClient;
+  if( zBlob && (!isBinary || pLog->log_data) ){
+    unsigned char *zRec;
+    int nWrite;
+
+    if( nBlob<0 ){
+      nBlob = strlen(zBlob);
+    }
+    nWrite = nBlob + 28;
+  
+    if( (nWrite+pLog->nBuf)>BINARYLOG_BUFFERSIZE ){
+      binarylog_flush(pLog);
+    }
+  
+    zRec = (unsigned char *)&pLog->zBuf[pLog->nBuf];
+    memset(zRec, 0, nWrite);
+    put32bits(&zRec[0], BINARYLOG_STRING);
+    put32bits(&zRec[4], (int)nBlob);
+    put32bits(&zRec[8], (int)isBinary);
+    memcpy(&zRec[28], zBlob, nBlob);
+    pLog->nBuf += nWrite;
+  }
+}
+
+void sqlite3_instvfs_binarylog_call(
+  sqlite3_vfs *pVfs,
+  int eEvent,
+  sqlite3_int64 nClick,
+  int return_code,
+  const char *zString
+){
+  InstVfs *pInstVfs = (InstVfs *)pVfs;
+  InstVfsBinaryLog *pLog = (InstVfsBinaryLog *)pInstVfs->pClient;
+
+  if( zString ){
+    binarylog_blob(pVfs, zString, -1, 0);
+  }
+  binarylog_xcall(pLog, eEvent, 0, nClick, return_code, 0, 0, 0, 0);
+}
+
+void sqlite3_instvfs_binarylog_marker(
+  sqlite3_vfs *pVfs,
+  const char *zMarker
+){
+  InstVfs *pInstVfs = (InstVfs *)pVfs;
+  InstVfsBinaryLog *pLog = (InstVfsBinaryLog *)pInstVfs->pClient;
+  binarylog_blob(pVfs, zMarker, -1, 0);
+  binarylog_xcall(pLog, BINARYLOG_MARKER, 0, 0, 0, 0, 0, 0, 0);
+}
+
+sqlite3_vfs *sqlite3_instvfs_binarylog(
+  const char *zVfs,
+  const char *zParentVfs, 
+  const char *zLog,
+  int log_data
+){
+  InstVfsBinaryLog *p;
+  sqlite3_vfs *pVfs;
+  sqlite3_vfs *pParent;
+  int nByte;
+  int flags;
+  int rc;
+
+  pParent = sqlite3_vfs_find(zParentVfs);
+  if( !pParent ){
+    return 0;
+  }
+
+  nByte = sizeof(InstVfsBinaryLog) + pParent->mxPathname+1;
+  p = (InstVfsBinaryLog *)sqlite3_malloc(nByte);
+  memset(p, 0, nByte);
+  p->zBuf = sqlite3_malloc(BINARYLOG_BUFFERSIZE);
+  p->zOut = (char *)&p[1];
+  p->pOut = (sqlite3_file *)sqlite3_malloc(pParent->szOsFile);
+  p->log_data = log_data;
+  pParent->xFullPathname(pParent, zLog, pParent->mxPathname, p->zOut);
+  flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MASTER_JOURNAL;
+  pParent->xDelete(pParent, p->zOut, 0);
+  rc = pParent->xOpen(pParent, p->zOut, p->pOut, flags, &flags);
+  if( rc==SQLITE_OK ){
+    memcpy(p->zBuf, "sqlite_ostrace1.....", 20);
+    p->iOffset = 0;
+    p->nBuf = 20;
+  }
+  if( rc ){
+    binarylog_xdel(p);
+    return 0;
+  }
+
+  pVfs = sqlite3_instvfs_create(zVfs, zParentVfs);
+  if( pVfs ){
+    sqlite3_instvfs_configure(pVfs, binarylog_xcall, p, binarylog_xdel);
+  }
+
+  return pVfs;
+}
+#endif /* SQLITE_ENABLE_INSTVFS */
+
+/**************************************************************************
+***************************************************************************
+** Tcl interface starts here.
+*/
+#if SQLITE_TEST
+
+#include "tcl.h"
+
+#ifdef SQLITE_ENABLE_INSTVFS
+struct InstVfsCall {
+  Tcl_Interp *interp;
+  Tcl_Obj *pScript;
+};
+typedef struct InstVfsCall InstVfsCall;
+
+static void test_instvfs_xcall(
+  void *p,
+  int eEvent,
+  int iFileId,
+  sqlite3_int64 nClick,
+  int return_code,
+  const char *zName,
+  int flags,
+  int nByte,
+  sqlite3_int64 iOffset
+){
+  int rc;
+  InstVfsCall *pCall = (InstVfsCall *)p;
+  Tcl_Obj *pObj = Tcl_DuplicateObj( pCall->pScript);
+  const char *zEvent = sqlite3_instvfs_name(eEvent);
+
+  Tcl_IncrRefCount(pObj);
+  Tcl_ListObjAppendElement(0, pObj, Tcl_NewStringObj(zEvent, -1));
+  Tcl_ListObjAppendElement(0, pObj, Tcl_NewWideIntObj(nClick));
+  Tcl_ListObjAppendElement(0, pObj, Tcl_NewStringObj(zName, -1));
+  Tcl_ListObjAppendElement(0, pObj, Tcl_NewIntObj(nByte));
+  Tcl_ListObjAppendElement(0, pObj, Tcl_NewWideIntObj(iOffset));
+
+  rc = Tcl_EvalObjEx(pCall->interp, pObj, TCL_EVAL_GLOBAL|TCL_EVAL_DIRECT);
+  if( rc ){
+    Tcl_BackgroundError(pCall->interp);
+  }
+  Tcl_DecrRefCount(pObj);
+}
+
+static void test_instvfs_xdel(void *p){
+  InstVfsCall *pCall = (InstVfsCall *)p;
+  Tcl_DecrRefCount(pCall->pScript);
+  sqlite3_free(pCall);
+}
+
+static int test_sqlite3_instvfs(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  static const char *IV_strs[] = 
+               { "create",  "destroy",  "reset",  "report", "configure", "binarylog", "marker", 0 };
+  enum IV_enum { IV_CREATE, IV_DESTROY, IV_RESET, IV_REPORT, IV_CONFIGURE, IV_BINARYLOG, IV_MARKER };
+  int iSub;
+
+  if( objc<2 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "SUB-COMMAND ...");
+  }
+  if( Tcl_GetIndexFromObj(interp, objv[1], IV_strs, "sub-command", 0, &iSub) ){
+    return TCL_ERROR;
+  }
+
+  switch( (enum IV_enum)iSub ){
+    case IV_CREATE: {
+      char *zParent = 0;
+      sqlite3_vfs *p;
+      int isDefault = 0;
+      if( objc>2 && 0==strcmp("-default", Tcl_GetString(objv[2])) ){
+        isDefault = 1;
+      }
+      if( (objc-isDefault)!=4 && (objc-isDefault)!=3 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "?-default? NAME ?PARENT-VFS?");
+        return TCL_ERROR;
+      }
+      if( objc==(4+isDefault) ){
+        zParent = Tcl_GetString(objv[3+isDefault]);
+      }
+      p = sqlite3_instvfs_create(Tcl_GetString(objv[2+isDefault]), zParent);
+      if( !p ){
+        Tcl_AppendResult(interp, "error creating vfs ", 0);
+        return TCL_ERROR;
+      }
+      if( isDefault ){
+        sqlite3_vfs_register(p, 1);
+      }
+      Tcl_SetObjResult(interp, objv[2]);
+      break;
+    }
+    case IV_BINARYLOG: {
+      char *zName = 0;
+      char *zLog = 0;
+      char *zParent = 0;
+      sqlite3_vfs *p;
+      int isDefault = 0;
+      int isLogdata = 0;
+      int argbase = 2;
+
+      for(argbase=2; argbase<(objc-2); argbase++){
+        if( 0==strcmp("-default", Tcl_GetString(objv[argbase])) ){
+          isDefault = 1;
+        }
+        else if( 0==strcmp("-parent", Tcl_GetString(objv[argbase])) ){
+          argbase++;
+          zParent = Tcl_GetString(objv[argbase]);
+        }
+        else if( 0==strcmp("-logdata", Tcl_GetString(objv[argbase])) ){
+          isLogdata = 1;
+        }else{
+          break;
+        }
+      }
+
+      if( (objc-argbase)!=2 ){
+        Tcl_WrongNumArgs(
+            interp, 2, objv, "?-default? ?-parent VFS? ?-logdata? NAME LOGFILE"
+        );
+        return TCL_ERROR;
+      }
+      zName = Tcl_GetString(objv[argbase]);
+      zLog = Tcl_GetString(objv[argbase+1]);
+      p = sqlite3_instvfs_binarylog(zName, zParent, zLog, isLogdata);
+      if( !p ){
+        Tcl_AppendResult(interp, "error creating vfs ", 0);
+        return TCL_ERROR;
+      }
+      if( isDefault ){
+        sqlite3_vfs_register(p, 1);
+      }
+      Tcl_SetObjResult(interp, objv[2]);
+      break;
+    }
+
+    case IV_MARKER: {
+      sqlite3_vfs *p;
+      if( objc!=4 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "VFS MARKER");
+        return TCL_ERROR;
+      }
+      p = sqlite3_vfs_find(Tcl_GetString(objv[2]));
+      if( !p || p->xOpen!=instOpen ){
+        Tcl_AppendResult(interp, "no such vfs: ", Tcl_GetString(objv[2]), 0);
+        return TCL_ERROR;
+      }
+      sqlite3_instvfs_binarylog_marker(p, Tcl_GetString(objv[3]));
+      Tcl_ResetResult(interp);
+      break;
+    }
+
+    case IV_CONFIGURE: {
+      InstVfsCall *pCall;
+
+      sqlite3_vfs *p;
+      if( objc!=4 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "NAME SCRIPT");
+        return TCL_ERROR;
+      }
+      p = sqlite3_vfs_find(Tcl_GetString(objv[2]));
+      if( !p || p->xOpen!=instOpen ){
+        Tcl_AppendResult(interp, "no such vfs: ", Tcl_GetString(objv[2]), 0);
+        return TCL_ERROR;
+      }
+
+      if( strlen(Tcl_GetString(objv[3])) ){
+        pCall = (InstVfsCall *)sqlite3_malloc(sizeof(InstVfsCall));
+        pCall->interp = interp;
+        pCall->pScript = Tcl_DuplicateObj(objv[3]);
+        Tcl_IncrRefCount(pCall->pScript);
+        sqlite3_instvfs_configure(p, 
+            test_instvfs_xcall, (void *)pCall, test_instvfs_xdel
+        );
+      }else{
+        sqlite3_instvfs_configure(p, 0, 0, 0);
+      }
+      break;
+    }
+
+    case IV_REPORT:
+    case IV_DESTROY:
+    case IV_RESET: {
+      sqlite3_vfs *p;
+      if( objc!=3 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "NAME");
+        return TCL_ERROR;
+      }
+      p = sqlite3_vfs_find(Tcl_GetString(objv[2]));
+      if( !p || p->xOpen!=instOpen ){
+        Tcl_AppendResult(interp, "no such vfs: ", Tcl_GetString(objv[2]), 0);
+        return TCL_ERROR;
+      }
+
+      if( ((enum IV_enum)iSub)==IV_DESTROY ){
+        sqlite3_instvfs_destroy(p);
+      }
+      if( ((enum IV_enum)iSub)==IV_RESET ){
+        sqlite3_instvfs_reset(p);
+      }
+      if( ((enum IV_enum)iSub)==IV_REPORT ){
+        int ii;
+        Tcl_Obj *pRet = Tcl_NewObj();
+
+        const char *zName = (char *)1;
+        sqlite3_int64 nClick;
+        int nCall;
+        for(ii=1; zName; ii++){
+          sqlite3_instvfs_get(p, ii, &zName, &nClick, &nCall);
+          if( zName ){
+            Tcl_Obj *pElem = Tcl_NewObj();
+            Tcl_ListObjAppendElement(0, pElem, Tcl_NewStringObj(zName, -1));
+            Tcl_ListObjAppendElement(0, pElem, Tcl_NewIntObj(nCall));
+            Tcl_ListObjAppendElement(0, pElem, Tcl_NewWideIntObj(nClick));
+            Tcl_ListObjAppendElement(0, pRet, pElem);
+          }
+        }
+
+        Tcl_SetObjResult(interp, pRet);
+      }
+
+      break;
+    }
+  }
+
+  return TCL_OK;
+}
+#endif /* SQLITE_ENABLE_INSTVFS */
+
+/* Alternative implementation of sqlite3_instvfs when the real
+** implementation is unavailable. 
+*/
+#ifndef SQLITE_ENABLE_INSTVFS
+static int test_sqlite3_instvfs(
+  void * clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  Tcl_AppendResult(interp, 
+     "not compiled with -DSQLITE_ENABLE_INSTVFS; sqlite3_instvfs is "
+     "unavailable", (char*)0);
+  return TCL_ERROR;
+}
+#endif /* !defined(SQLITE_ENABLE_INSTVFS) */
+
+int SqlitetestOsinst_Init(Tcl_Interp *interp){
+  Tcl_CreateObjCommand(interp, "sqlite3_instvfs", test_sqlite3_instvfs, 0, 0);
+  return TCL_OK;
+}
+
+#endif /* SQLITE_TEST */