Add //third_party/sqlite to dirs_to_snapshot, remove net_sql.patch

third_party/sqlite/sqlite-src-3080704/src/test_osinst.c

+/*
+** 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.
+*/
+
+/*
+** This module contains code for a wrapper VFS that causes a log of
+** most VFS calls to be written into a nominated file on disk. The log 
+** is stored in a compressed binary format to reduce the amount of IO 
+** overhead introduced into the application by logging.
+**
+** All calls on sqlite3_file objects except xFileControl() are logged.
+** Additionally, calls to the xAccess(), xOpen(), and xDelete()
+** methods are logged. The other sqlite3_vfs object methods (xDlXXX,
+** xRandomness, xSleep, xCurrentTime, xGetLastError and xCurrentTimeInt64) 
+** are not logged.
+**
+** The binary log files are read using a virtual table implementation
+** also contained in this file. 
+**
+** CREATING LOG FILES:
+**
+**       int sqlite3_vfslog_new(
+**         const char *zVfs,          // Name of new VFS
+**         const char *zParentVfs,    // Name of parent VFS (or NULL)
+**         const char *zLog           // Name of log file to write to
+**       );
+**
+**       int sqlite3_vfslog_finalize(const char *zVfs);
+**
+** ANNOTATING LOG FILES:
+**
+**   To write an arbitrary message into a log file:
+**
+**       int sqlite3_vfslog_annotate(const char *zVfs, const char *zMsg);
+**
+** READING LOG FILES:
+**
+**   Log files are read using the "vfslog" virtual table implementation
+**   in this file. To register the virtual table with SQLite, use:
+**
+**       int sqlite3_vfslog_register(sqlite3 *db);
+**
+**   Then, if the log file is named "vfs.log", the following SQL command:
+**
+**       CREATE VIRTUAL TABLE v USING vfslog('vfs.log');
+**
+**   creates a virtual table with 6 columns, as follows:
+**
+**       CREATE TABLE v(
+**         event    TEXT,             // "xOpen", "xRead" etc.
+**         file     TEXT,             // Name of file this call applies to
+**         clicks   INTEGER,          // Time spent in call
+**         rc       INTEGER,          // Return value
+**         size     INTEGER,          // Bytes read or written
+**         offset   INTEGER           // File offset read or written
+**       );
+*/
+
+#include "sqlite3.h"
+
+#include "os_setup.h"
+#if SQLITE_OS_WIN
+#  include "os_win.h"
+#endif
+
+#include <string.h>
+#include <assert.h>
+
+
+/*
+** Maximum pathname length supported by the vfslog backend.
+*/
+#define INST_MAX_PATHNAME 512
+
+#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_SHMUNMAP          22
+#define OS_SHMMAP            23
+#define OS_SHMLOCK           25
+#define OS_SHMBARRIER        26
+#define OS_ANNOTATE          28
+
+#define OS_NUMEVENTS         29
+
+#define VFSLOG_BUFFERSIZE 8192
+
+typedef struct VfslogVfs VfslogVfs;
+typedef struct VfslogFile VfslogFile;
+
+struct VfslogVfs {
+  sqlite3_vfs base;               /* VFS methods */
+  sqlite3_vfs *pVfs;              /* Parent VFS */
+  int iNextFileId;                /* Next file id */
+  sqlite3_file *pLog;             /* Log file handle */
+  sqlite3_int64 iOffset;          /* Log file offset of start of write buffer */
+  int nBuf;                       /* Number of valid bytes in aBuf[] */
+  char aBuf[VFSLOG_BUFFERSIZE];   /* Write buffer */
+};
+
+struct VfslogFile {
+  sqlite3_file base;              /* IO methods */
+  sqlite3_file *pReal;            /* Underlying file handle */
+  sqlite3_vfs *pVfslog;           /* Associated VsflogVfs object */
+  int iFileId;                    /* File id number */
+};
+
+#define REALVFS(p) (((VfslogVfs *)(p))->pVfs)
+
+
+
+/*
+** Method declarations for vfslog_file.
+*/
+static int vfslogClose(sqlite3_file*);
+static int vfslogRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);
+static int vfslogWrite(sqlite3_file*,const void*,int iAmt, sqlite3_int64 iOfst);
+static int vfslogTruncate(sqlite3_file*, sqlite3_int64 size);
+static int vfslogSync(sqlite3_file*, int flags);
+static int vfslogFileSize(sqlite3_file*, sqlite3_int64 *pSize);
+static int vfslogLock(sqlite3_file*, int);
+static int vfslogUnlock(sqlite3_file*, int);
+static int vfslogCheckReservedLock(sqlite3_file*, int *pResOut);
+static int vfslogFileControl(sqlite3_file*, int op, void *pArg);
+static int vfslogSectorSize(sqlite3_file*);
+static int vfslogDeviceCharacteristics(sqlite3_file*);
+
+static int vfslogShmLock(sqlite3_file *pFile, int ofst, int n, int flags);
+static int vfslogShmMap(sqlite3_file *pFile,int,int,int,volatile void **);
+static void vfslogShmBarrier(sqlite3_file*);
+static int vfslogShmUnmap(sqlite3_file *pFile, int deleteFlag);
+
+/*
+** Method declarations for vfslog_vfs.
+*/
+static int vfslogOpen(sqlite3_vfs*, const char *, sqlite3_file*, int , int *);
+static int vfslogDelete(sqlite3_vfs*, const char *zName, int syncDir);
+static int vfslogAccess(sqlite3_vfs*, const char *zName, int flags, int *);
+static int vfslogFullPathname(sqlite3_vfs*, const char *zName, int, char *zOut);
+static void *vfslogDlOpen(sqlite3_vfs*, const char *zFilename);
+static void vfslogDlError(sqlite3_vfs*, int nByte, char *zErrMsg);
+static void (*vfslogDlSym(sqlite3_vfs *pVfs, void *p, const char*zSym))(void);
+static void vfslogDlClose(sqlite3_vfs*, void*);
+static int vfslogRandomness(sqlite3_vfs*, int nByte, char *zOut);
+static int vfslogSleep(sqlite3_vfs*, int microseconds);
+static int vfslogCurrentTime(sqlite3_vfs*, double*);
+
+static int vfslogGetLastError(sqlite3_vfs*, int, char *);
+static int vfslogCurrentTimeInt64(sqlite3_vfs*, sqlite3_int64*);
+
+static sqlite3_vfs vfslog_vfs = {
+  1,                              /* iVersion */
+  sizeof(VfslogFile),             /* szOsFile */
+  INST_MAX_PATHNAME,              /* mxPathname */
+  0,                              /* pNext */
+  0,                              /* zName */
+  0,                              /* pAppData */
+  vfslogOpen,                     /* xOpen */
+  vfslogDelete,                   /* xDelete */
+  vfslogAccess,                   /* xAccess */
+  vfslogFullPathname,             /* xFullPathname */
+  vfslogDlOpen,                   /* xDlOpen */
+  vfslogDlError,                  /* xDlError */
+  vfslogDlSym,                    /* xDlSym */
+  vfslogDlClose,                  /* xDlClose */
+  vfslogRandomness,               /* xRandomness */
+  vfslogSleep,                    /* xSleep */
+  vfslogCurrentTime,              /* xCurrentTime */
+  vfslogGetLastError,             /* xGetLastError */
+  vfslogCurrentTimeInt64          /* xCurrentTime */
+};
+
+static sqlite3_io_methods vfslog_io_methods = {
+  2,                              /* iVersion */
+  vfslogClose,                    /* xClose */
+  vfslogRead,                     /* xRead */
+  vfslogWrite,                    /* xWrite */
+  vfslogTruncate,                 /* xTruncate */
+  vfslogSync,                     /* xSync */
+  vfslogFileSize,                 /* xFileSize */
+  vfslogLock,                     /* xLock */
+  vfslogUnlock,                   /* xUnlock */
+  vfslogCheckReservedLock,        /* xCheckReservedLock */
+  vfslogFileControl,              /* xFileControl */
+  vfslogSectorSize,               /* xSectorSize */
+  vfslogDeviceCharacteristics,    /* xDeviceCharacteristics */
+  vfslogShmMap,                   /* xShmMap */
+  vfslogShmLock,                  /* xShmLock */
+  vfslogShmBarrier,               /* xShmBarrier */
+  vfslogShmUnmap                  /* xShmUnmap */
+};
+
+#if SQLITE_OS_UNIX && !defined(NO_GETTOD)
+#include <sys/time.h>
+static sqlite3_uint64 vfslog_time(){
+  struct timeval sTime;
+  gettimeofday(&sTime, 0);
+  return sTime.tv_usec + (sqlite3_uint64)sTime.tv_sec * 1000000;
+}
+#elif SQLITE_OS_WIN
+#include <time.h>
+static sqlite3_uint64 vfslog_time(){
+  FILETIME ft;
+  sqlite3_uint64 u64time = 0;
+ 
+  GetSystemTimeAsFileTime(&ft);
+
+  u64time |= ft.dwHighDateTime;
+  u64time <<= 32;
+  u64time |= ft.dwLowDateTime;
+
+  /* ft is 100-nanosecond intervals, we want microseconds */
+  return u64time /(sqlite3_uint64)10;
+}
+#else
+static sqlite3_uint64 vfslog_time(){
+  return 0;
+}
+#endif
+
+static void vfslog_call(sqlite3_vfs *, int, int, sqlite3_int64, int, int, int);
+static void vfslog_string(sqlite3_vfs *, const char *);
+
+/*
+** Close an vfslog-file.
+*/
+static int vfslogClose(sqlite3_file *pFile){
+  sqlite3_uint64 t;
+  int rc = SQLITE_OK;
+  VfslogFile *p = (VfslogFile *)pFile;
+
+  t = vfslog_time();
+  if( p->pReal->pMethods ){
+    rc = p->pReal->pMethods->xClose(p->pReal);
+  }
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_CLOSE, p->iFileId, t, rc, 0, 0);
+  return rc;
+}
+
+/*
+** Read data from an vfslog-file.
+*/
+static int vfslogRead(
+  sqlite3_file *pFile, 
+  void *zBuf, 
+  int iAmt, 
+  sqlite_int64 iOfst
+){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xRead(p->pReal, zBuf, iAmt, iOfst);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_READ, p->iFileId, t, rc, iAmt, (int)iOfst);
+  return rc;
+}
+
+/*
+** Write data to an vfslog-file.
+*/
+static int vfslogWrite(
+  sqlite3_file *pFile,
+  const void *z,
+  int iAmt,
+  sqlite_int64 iOfst
+){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xWrite(p->pReal, z, iAmt, iOfst);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_WRITE, p->iFileId, t, rc, iAmt, (int)iOfst);
+  return rc;
+}
+
+/*
+** Truncate an vfslog-file.
+*/
+static int vfslogTruncate(sqlite3_file *pFile, sqlite_int64 size){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xTruncate(p->pReal, size);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_TRUNCATE, p->iFileId, t, rc, 0, (int)size);
+  return rc;
+}
+
+/*
+** Sync an vfslog-file.
+*/
+static int vfslogSync(sqlite3_file *pFile, int flags){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xSync(p->pReal, flags);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_SYNC, p->iFileId, t, rc, flags, 0);
+  return rc;
+}
+
+/*
+** Return the current file-size of an vfslog-file.
+*/
+static int vfslogFileSize(sqlite3_file *pFile, sqlite_int64 *pSize){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xFileSize(p->pReal, pSize);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_FILESIZE, p->iFileId, t, rc, 0, (int)*pSize);
+  return rc;
+}
+
+/*
+** Lock an vfslog-file.
+*/
+static int vfslogLock(sqlite3_file *pFile, int eLock){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xLock(p->pReal, eLock);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_LOCK, p->iFileId, t, rc, eLock, 0);
+  return rc;
+}
+
+/*
+** Unlock an vfslog-file.
+*/
+static int vfslogUnlock(sqlite3_file *pFile, int eLock){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xUnlock(p->pReal, eLock);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_UNLOCK, p->iFileId, t, rc, eLock, 0);
+  return rc;
+}
+
+/*
+** Check if another file-handle holds a RESERVED lock on an vfslog-file.
+*/
+static int vfslogCheckReservedLock(sqlite3_file *pFile, int *pResOut){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xCheckReservedLock(p->pReal, pResOut);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_CHECKRESERVEDLOCK, p->iFileId, t, rc, *pResOut, 0);
+  return rc;
+}
+
+/*
+** File control method. For custom operations on an vfslog-file.
+*/
+static int vfslogFileControl(sqlite3_file *pFile, int op, void *pArg){
+  VfslogFile *p = (VfslogFile *)pFile;
+  int rc = p->pReal->pMethods->xFileControl(p->pReal, op, pArg);
+  if( op==SQLITE_FCNTL_VFSNAME && rc==SQLITE_OK ){
+    *(char**)pArg = sqlite3_mprintf("vfslog/%z", *(char**)pArg);
+  }
+  return rc;
+}
+
+/*
+** Return the sector-size in bytes for an vfslog-file.
+*/
+static int vfslogSectorSize(sqlite3_file *pFile){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xSectorSize(p->pReal);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_SECTORSIZE, p->iFileId, t, rc, 0, 0);
+  return rc;
+}
+
+/*
+** Return the device characteristic flags supported by an vfslog-file.
+*/
+static int vfslogDeviceCharacteristics(sqlite3_file *pFile){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xDeviceCharacteristics(p->pReal);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_DEVCHAR, p->iFileId, t, rc, 0, 0);
+  return rc;
+}
+
+static int vfslogShmLock(sqlite3_file *pFile, int ofst, int n, int flags){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xShmLock(p->pReal, ofst, n, flags);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_SHMLOCK, p->iFileId, t, rc, 0, 0);
+  return rc;
+}
+static int vfslogShmMap(
+  sqlite3_file *pFile, 
+  int iRegion, 
+  int szRegion, 
+  int isWrite, 
+  volatile void **pp
+){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xShmMap(p->pReal, iRegion, szRegion, isWrite, pp);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_SHMMAP, p->iFileId, t, rc, 0, 0);
+  return rc;
+}
+static void vfslogShmBarrier(sqlite3_file *pFile){
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  p->pReal->pMethods->xShmBarrier(p->pReal);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_SHMBARRIER, p->iFileId, t, SQLITE_OK, 0, 0);
+}
+static int vfslogShmUnmap(sqlite3_file *pFile, int deleteFlag){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  t = vfslog_time();
+  rc = p->pReal->pMethods->xShmUnmap(p->pReal, deleteFlag);
+  t = vfslog_time() - t;
+  vfslog_call(p->pVfslog, OS_SHMUNMAP, p->iFileId, t, rc, 0, 0);
+  return rc;
+}
+
+
+/*
+** Open an vfslog file handle.
+*/
+static int vfslogOpen(
+  sqlite3_vfs *pVfs,
+  const char *zName,
+  sqlite3_file *pFile,
+  int flags,
+  int *pOutFlags
+){
+  int rc;
+  sqlite3_uint64 t;
+  VfslogFile *p = (VfslogFile *)pFile;
+  VfslogVfs *pLog = (VfslogVfs *)pVfs;
+
+  pFile->pMethods = &vfslog_io_methods;
+  p->pReal = (sqlite3_file *)&p[1];
+  p->pVfslog = pVfs;
+  p->iFileId = ++pLog->iNextFileId;
+
+  t = vfslog_time();
+  rc = REALVFS(pVfs)->xOpen(REALVFS(pVfs), zName, p->pReal, flags, pOutFlags);
+  t = vfslog_time() - t;
+
+  vfslog_call(pVfs, OS_OPEN, p->iFileId, t, rc, 0, 0);
+  vfslog_string(pVfs, zName);
+  return rc;
+}
+
+/*
+** 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 vfslogDelete(sqlite3_vfs *pVfs, const char *zPath, int dirSync){
+  int rc;
+  sqlite3_uint64 t;
+  t = vfslog_time();
+  rc = REALVFS(pVfs)->xDelete(REALVFS(pVfs), zPath, dirSync);
+  t = vfslog_time() - t;
+  vfslog_call(pVfs, OS_DELETE, 0, t, rc, dirSync, 0);
+  vfslog_string(pVfs, zPath);
+  return rc;
+}
+
+/*
+** Test for access permissions. Return true if the requested permission
+** is available, or false otherwise.
+*/
+static int vfslogAccess(
+  sqlite3_vfs *pVfs, 
+  const char *zPath, 
+  int flags, 
+  int *pResOut
+){
+  int rc;
+  sqlite3_uint64 t;
+  t = vfslog_time();
+  rc = REALVFS(pVfs)->xAccess(REALVFS(pVfs), zPath, flags, pResOut);
+  t = vfslog_time() - t;
+  vfslog_call(pVfs, OS_ACCESS, 0, t, rc, flags, *pResOut);
+  vfslog_string(pVfs, zPath);
+  return rc;
+}
+
+/*
+** 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 vfslogFullPathname(
+  sqlite3_vfs *pVfs, 
+  const char *zPath, 
+  int nOut, 
+  char *zOut
+){
+  return REALVFS(pVfs)->xFullPathname(REALVFS(pVfs), zPath, nOut, zOut);
+}
+
+/*
+** Open the dynamic library located at zPath and return a handle.
+*/
+static void *vfslogDlOpen(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 vfslogDlError(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 (*vfslogDlSym(sqlite3_vfs *pVfs, void *p, const char *zSym))(void){
+  return REALVFS(pVfs)->xDlSym(REALVFS(pVfs), p, zSym);
+}
+
+/*
+** Close the dynamic library handle pHandle.
+*/
+static void vfslogDlClose(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 vfslogRandomness(sqlite3_vfs *pVfs, int nByte, char *zBufOut){
+  return REALVFS(pVfs)->xRandomness(REALVFS(pVfs), nByte, zBufOut);
+}
+
+/*
+** Sleep for nMicro microseconds. Return the number of microseconds 
+** actually slept.
+*/
+static int vfslogSleep(sqlite3_vfs *pVfs, int nMicro){
+  return REALVFS(pVfs)->xSleep(REALVFS(pVfs), nMicro);
+}
+
+/*
+** Return the current time as a Julian Day number in *pTimeOut.
+*/
+static int vfslogCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
+  return REALVFS(pVfs)->xCurrentTime(REALVFS(pVfs), pTimeOut);
+}
+
+static int vfslogGetLastError(sqlite3_vfs *pVfs, int a, char *b){
+  return REALVFS(pVfs)->xGetLastError(REALVFS(pVfs), a, b);
+}
+static int vfslogCurrentTimeInt64(sqlite3_vfs *pVfs, sqlite3_int64 *p){
+  return REALVFS(pVfs)->xCurrentTimeInt64(REALVFS(pVfs), p);
+}
+
+static void vfslog_flush(VfslogVfs *p){
+#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
+
+  if( p->nBuf ){
+    p->pLog->pMethods->xWrite(p->pLog, p->aBuf, p->nBuf, p->iOffset);
+    p->iOffset += p->nBuf;
+    p->nBuf = 0;
+  }
+
+#ifdef SQLITE_TEST
+  sqlite3_io_error_pending = pending;
+  sqlite3_io_error_persist = persist;
+  sqlite3_diskfull_pending = diskfull;
+#endif
+}
+
+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 vfslog_call(
+  sqlite3_vfs *pVfs,
+  int eEvent,
+  int iFileid,
+  sqlite3_int64 nClick,
+  int return_code,
+  int size,
+  int offset
+){
+  VfslogVfs *p = (VfslogVfs *)pVfs;
+  unsigned char *zRec;
+  if( (24+p->nBuf)>sizeof(p->aBuf) ){
+    vfslog_flush(p);
+  }
+  zRec = (unsigned char *)&p->aBuf[p->nBuf];
+  put32bits(&zRec[0], eEvent);
+  put32bits(&zRec[4], iFileid);
+  put32bits(&zRec[8], (unsigned int)(nClick&0xffff));
+  put32bits(&zRec[12], return_code);
+  put32bits(&zRec[16], size);
+  put32bits(&zRec[20], offset);
+  p->nBuf += 24;
+}
+
+static void vfslog_string(sqlite3_vfs *pVfs, const char *zStr){
+  VfslogVfs *p = (VfslogVfs *)pVfs;
+  unsigned char *zRec;
+  int nStr = zStr ? (int)strlen(zStr) : 0;
+  if( (4+nStr+p->nBuf)>sizeof(p->aBuf) ){
+    vfslog_flush(p);
+  }
+  zRec = (unsigned char *)&p->aBuf[p->nBuf];
+  put32bits(&zRec[0], nStr);
+  if( zStr ){
+    memcpy(&zRec[4], zStr, nStr);
+  }
+  p->nBuf += (4 + nStr);
+}
+
+static void vfslog_finalize(VfslogVfs *p){
+  if( p->pLog->pMethods ){
+    vfslog_flush(p);
+    p->pLog->pMethods->xClose(p->pLog);
+  }
+  sqlite3_free(p);
+}
+
+int sqlite3_vfslog_finalize(const char *zVfs){
+  sqlite3_vfs *pVfs;
+  pVfs = sqlite3_vfs_find(zVfs);
+  if( !pVfs || pVfs->xOpen!=vfslogOpen ){
+    return SQLITE_ERROR;
+  } 
+  sqlite3_vfs_unregister(pVfs);
+  vfslog_finalize((VfslogVfs *)pVfs);
+  return SQLITE_OK;
+}
+
+int sqlite3_vfslog_new(
+  const char *zVfs,               /* New VFS name */
+  const char *zParentVfs,         /* Parent VFS name (or NULL) */
+  const char *zLog                /* Log file name */
+){
+  VfslogVfs *p;
+  sqlite3_vfs *pParent;
+  int nByte;
+  int flags;
+  int rc;
+  char *zFile;
+  int nVfs;
+
+  pParent = sqlite3_vfs_find(zParentVfs);
+  if( !pParent ){
+    return SQLITE_ERROR;
+  }
+
+  nVfs = (int)strlen(zVfs);
+  nByte = sizeof(VfslogVfs) + pParent->szOsFile + nVfs+1+pParent->mxPathname+1;
+  p = (VfslogVfs *)sqlite3_malloc(nByte);
+  memset(p, 0, nByte);
+
+  p->pVfs = pParent;
+  p->pLog = (sqlite3_file *)&p[1];
+  memcpy(&p->base, &vfslog_vfs, sizeof(sqlite3_vfs));
+  p->base.zName = &((char *)p->pLog)[pParent->szOsFile];
+  p->base.szOsFile += pParent->szOsFile;
+  memcpy((char *)p->base.zName, zVfs, nVfs);
+
+  zFile = (char *)&p->base.zName[nVfs+1];
+  pParent->xFullPathname(pParent, zLog, pParent->mxPathname, zFile);
+
+  flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MASTER_JOURNAL;
+  pParent->xDelete(pParent, zFile, 0);
+  rc = pParent->xOpen(pParent, zFile, p->pLog, flags, &flags);
+  if( rc==SQLITE_OK ){
+    memcpy(p->aBuf, "sqlite_ostrace1.....", 20);
+    p->iOffset = 0;
+    p->nBuf = 20;
+    rc = sqlite3_vfs_register((sqlite3_vfs *)p, 1);
+  }
+  if( rc ){
+    vfslog_finalize(p);
+  }
+  return rc;
+}
+
+int sqlite3_vfslog_annotate(const char *zVfs, const char *zMsg){
+  sqlite3_vfs *pVfs;
+  pVfs = sqlite3_vfs_find(zVfs);
+  if( !pVfs || pVfs->xOpen!=vfslogOpen ){
+    return SQLITE_ERROR;
+  } 
+  vfslog_call(pVfs, OS_ANNOTATE, 0, 0, 0, 0, 0);
+  vfslog_string(pVfs, zMsg);
+  return SQLITE_OK;
+}
+
+static const char *vfslog_eventname(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 = "xCheckResLock"; break;
+    case OS_FILECONTROL:       zEvent = "xFileControl"; break;
+    case OS_SECTORSIZE:        zEvent = "xSectorSize"; break;
+    case OS_DEVCHAR:           zEvent = "xDeviceChar"; 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;
+
+    case OS_SHMUNMAP:          zEvent = "xShmUnmap"; break;
+    case OS_SHMLOCK:           zEvent = "xShmLock"; break;
+    case OS_SHMBARRIER:        zEvent = "xShmBarrier"; break;
+    case OS_SHMMAP:            zEvent = "xShmMap"; break;
+
+    case OS_ANNOTATE:          zEvent = "annotation"; break;
+  }
+
+  return zEvent;
+}
+
+typedef struct VfslogVtab VfslogVtab;
+typedef struct VfslogCsr VfslogCsr;
+
+/*
+** Virtual table type for the vfslog reader module.
+*/
+struct VfslogVtab {
+  sqlite3_vtab base;              /* Base class */
+  sqlite3_file *pFd;              /* File descriptor open on vfslog file */
+  sqlite3_int64 nByte;            /* Size of file in bytes */
+  char *zFile;                    /* File name for pFd */
+};
+
+/*
+** Virtual table cursor type for the vfslog reader module.
+*/
+struct VfslogCsr {
+  sqlite3_vtab_cursor base;       /* Base class */
+  sqlite3_int64 iRowid;           /* Current rowid. */
+  sqlite3_int64 iOffset;          /* Offset of next record in file */
+  char *zTransient;               /* Transient 'file' string */
+  int nFile;                      /* Size of array azFile[] */
+  char **azFile;                  /* File strings */
+  unsigned char aBuf[1024];       /* Current vfs log entry (read from file) */
+};
+
+static unsigned int get32bits(unsigned char *p){
+  return (p[0]<<24) + (p[1]<<16) + (p[2]<<8) + p[3];
+}
+
+/*
+** The argument must point to a buffer containing a nul-terminated string.
+** If the string begins with an SQL quote character it is overwritten by
+** the dequoted version. Otherwise the buffer is left unmodified.
+*/
+static void dequote(char *z){
+  char quote;                     /* Quote character (if any ) */
+  quote = z[0];
+  if( quote=='[' || quote=='\'' || quote=='"' || quote=='`' ){
+    int iIn = 1;                  /* Index of next byte to read from input */
+    int iOut = 0;                 /* Index of next byte to write to output */
+    if( quote=='[' ) quote = ']';  
+    while( z[iIn] ){
+      if( z[iIn]==quote ){
+        if( z[iIn+1]!=quote ) break;
+        z[iOut++] = quote;
+        iIn += 2;
+      }else{
+        z[iOut++] = z[iIn++];
+      }
+    }
+    z[iOut] = '\0';
+  }
+}
+
+#ifndef SQLITE_OMIT_VIRTUALTABLE
+/*
+** Connect to or create a vfslog virtual table.
+*/
+static int vlogConnect(
+  sqlite3 *db,
+  void *pAux,
+  int argc, const char *const*argv,
+  sqlite3_vtab **ppVtab,
+  char **pzErr
+){
+  sqlite3_vfs *pVfs;              /* VFS used to read log file */
+  int flags;                      /* flags passed to pVfs->xOpen() */
+  VfslogVtab *p;
+  int rc;
+  int nByte;
+  char *zFile;
+
+  *ppVtab = 0;
+  pVfs = sqlite3_vfs_find(0);
+  nByte = sizeof(VfslogVtab) + pVfs->szOsFile + pVfs->mxPathname;
+  p = sqlite3_malloc(nByte);
+  if( p==0 ) return SQLITE_NOMEM;
+  memset(p, 0, nByte);
+
+  p->pFd = (sqlite3_file *)&p[1];
+  p->zFile = &((char *)p->pFd)[pVfs->szOsFile];
+
+  zFile = sqlite3_mprintf("%s", argv[3]);
+  if( !zFile ){
+    sqlite3_free(p);
+    return SQLITE_NOMEM;
+  }
+  dequote(zFile);
+  pVfs->xFullPathname(pVfs, zFile, pVfs->mxPathname, p->zFile);
+  sqlite3_free(zFile);
+
+  flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_MASTER_JOURNAL;
+  rc = pVfs->xOpen(pVfs, p->zFile, p->pFd, flags, &flags);
+
+  if( rc==SQLITE_OK ){
+    p->pFd->pMethods->xFileSize(p->pFd, &p->nByte);
+    sqlite3_declare_vtab(db, 
+        "CREATE TABLE xxx(event, file, click, rc, size, offset)"
+    );
+    *ppVtab = &p->base;
+  }else{
+    sqlite3_free(p);
+  }
+
+  return rc;
+}
+
+/*
+** There is no "best-index". This virtual table always does a linear
+** scan of the binary VFS log file.
+*/
+static int vlogBestIndex(sqlite3_vtab *tab, sqlite3_index_info *pIdxInfo){
+  pIdxInfo->estimatedCost = 10.0;
+  return SQLITE_OK;
+}
+
+/*
+** Disconnect from or destroy a vfslog virtual table.
+*/
+static int vlogDisconnect(sqlite3_vtab *pVtab){
+  VfslogVtab *p = (VfslogVtab *)pVtab;
+  if( p->pFd->pMethods ){
+    p->pFd->pMethods->xClose(p->pFd);
+    p->pFd->pMethods = 0;
+  }
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Open a new vfslog cursor.
+*/
+static int vlogOpen(sqlite3_vtab *pVTab, sqlite3_vtab_cursor **ppCursor){
+  VfslogCsr *pCsr;                /* Newly allocated cursor object */
+
+  pCsr = sqlite3_malloc(sizeof(VfslogCsr));
+  if( !pCsr ) return SQLITE_NOMEM;
+  memset(pCsr, 0, sizeof(VfslogCsr));
+  *ppCursor = &pCsr->base;
+  return SQLITE_OK;
+}
+
+/*
+** Close a vfslog cursor.
+*/
+static int vlogClose(sqlite3_vtab_cursor *pCursor){
+  VfslogCsr *p = (VfslogCsr *)pCursor;
+  int i;
+  for(i=0; i<p->nFile; i++){
+    sqlite3_free(p->azFile[i]);
+  }
+  sqlite3_free(p->azFile);
+  sqlite3_free(p->zTransient);
+  sqlite3_free(p);
+  return SQLITE_OK;
+}
+
+/*
+** Move a vfslog cursor to the next entry in the file.
+*/
+static int vlogNext(sqlite3_vtab_cursor *pCursor){
+  VfslogCsr *pCsr = (VfslogCsr *)pCursor;
+  VfslogVtab *p = (VfslogVtab *)pCursor->pVtab;
+  int rc = SQLITE_OK;
+  int nRead;
+
+  sqlite3_free(pCsr->zTransient);
+  pCsr->zTransient = 0;
+
+  nRead = 24;
+  if( pCsr->iOffset+nRead<=p->nByte ){
+    int eEvent;
+    rc = p->pFd->pMethods->xRead(p->pFd, pCsr->aBuf, nRead, pCsr->iOffset);
+
+    eEvent = get32bits(pCsr->aBuf);
+    if( (rc==SQLITE_OK)
+     && (eEvent==OS_OPEN || eEvent==OS_DELETE || eEvent==OS_ACCESS) 
+    ){
+      char buf[4];
+      rc = p->pFd->pMethods->xRead(p->pFd, buf, 4, pCsr->iOffset+nRead);
+      nRead += 4;
+      if( rc==SQLITE_OK ){
+        int nStr = get32bits((unsigned char *)buf);
+        char *zStr = sqlite3_malloc(nStr+1);
+        rc = p->pFd->pMethods->xRead(p->pFd, zStr, nStr, pCsr->iOffset+nRead);
+        zStr[nStr] = '\0';
+        nRead += nStr;
+
+        if( eEvent==OS_OPEN ){
+          int iFileid = get32bits(&pCsr->aBuf[4]);
+          if( iFileid>=pCsr->nFile ){
+            int nNew = sizeof(pCsr->azFile[0])*(iFileid+1);
+            pCsr->azFile = (char **)sqlite3_realloc(pCsr->azFile, nNew);
+            nNew -= sizeof(pCsr->azFile[0])*pCsr->nFile;
+            memset(&pCsr->azFile[pCsr->nFile], 0, nNew);
+            pCsr->nFile = iFileid+1;
+          }
+          sqlite3_free(pCsr->azFile[iFileid]);
+          pCsr->azFile[iFileid] = zStr;
+        }else{
+          pCsr->zTransient = zStr;
+        }
+      }
+    }
+  }
+
+  pCsr->iRowid += 1;
+  pCsr->iOffset += nRead;
+  return rc;
+}
+
+static int vlogEof(sqlite3_vtab_cursor *pCursor){
+  VfslogCsr *pCsr = (VfslogCsr *)pCursor;
+  VfslogVtab *p = (VfslogVtab *)pCursor->pVtab;
+  return (pCsr->iOffset>=p->nByte);
+}
+
+static int vlogFilter(
+  sqlite3_vtab_cursor *pCursor, 
+  int idxNum, const char *idxStr,
+  int argc, sqlite3_value **argv
+){
+  VfslogCsr *pCsr = (VfslogCsr *)pCursor;
+  pCsr->iRowid = 0;
+  pCsr->iOffset = 20;
+  return vlogNext(pCursor);
+}
+
+static int vlogColumn(
+  sqlite3_vtab_cursor *pCursor, 
+  sqlite3_context *ctx, 
+  int i
+){
+  unsigned int val;
+  VfslogCsr *pCsr = (VfslogCsr *)pCursor;
+
+  assert( i<7 );
+  val = get32bits(&pCsr->aBuf[4*i]);
+
+  switch( i ){
+    case 0: {
+      sqlite3_result_text(ctx, vfslog_eventname(val), -1, SQLITE_STATIC);
+      break;
+    }
+    case 1: {
+      char *zStr = pCsr->zTransient;
+      if( val!=0 && val<(unsigned)pCsr->nFile ){
+        zStr = pCsr->azFile[val];
+      }
+      sqlite3_result_text(ctx, zStr, -1, SQLITE_TRANSIENT);
+      break;
+    }
+    default:
+      sqlite3_result_int(ctx, val);
+      break;
+  }
+
+  return SQLITE_OK;
+}
+
+static int vlogRowid(sqlite3_vtab_cursor *pCursor, sqlite_int64 *pRowid){
+  VfslogCsr *pCsr = (VfslogCsr *)pCursor;
+  *pRowid = pCsr->iRowid;
+  return SQLITE_OK;
+}
+
+int sqlite3_vfslog_register(sqlite3 *db){
+  static sqlite3_module vfslog_module = {
+    0,                            /* iVersion */
+    vlogConnect,                /* xCreate */
+    vlogConnect,                /* xConnect */
+    vlogBestIndex,              /* xBestIndex */
+    vlogDisconnect,             /* xDisconnect */
+    vlogDisconnect,             /* xDestroy */
+    vlogOpen,                   /* xOpen - open a cursor */
+    vlogClose,                  /* xClose - close a cursor */
+    vlogFilter,                 /* xFilter - configure scan constraints */
+    vlogNext,                   /* xNext - advance a cursor */
+    vlogEof,                    /* xEof - check for end of scan */
+    vlogColumn,                 /* xColumn - read data */
+    vlogRowid,                  /* xRowid - read data */
+    0,                            /* xUpdate */
+    0,                            /* xBegin */
+    0,                            /* xSync */
+    0,                            /* xCommit */
+    0,                            /* xRollback */
+    0,                            /* xFindMethod */
+    0,                            /* xRename */
+  };
+
+  sqlite3_create_module(db, "vfslog", &vfslog_module, 0);
+  return SQLITE_OK;
+}
+#endif /* SQLITE_OMIT_VIRTUALTABLE */
+
+/**************************************************************************
+***************************************************************************
+** Tcl interface starts here.
+*/
+
+#if defined(SQLITE_TEST) || defined(TCLSH)
+
+#include <tcl.h>
+
+static int test_vfslog(
+  void *clientData,
+  Tcl_Interp *interp,
+  int objc,
+  Tcl_Obj *CONST objv[]
+){
+  struct SqliteDb { sqlite3 *db; };
+  sqlite3 *db;
+  Tcl_CmdInfo cmdInfo;
+  int rc = SQLITE_ERROR;
+
+  static const char *strs[] = { "annotate", "finalize", "new",  "register", 0 };
+  enum VL_enum { VL_ANNOTATE, VL_FINALIZE, VL_NEW, VL_REGISTER };
+  int iSub;
+
+  if( objc<2 ){
+    Tcl_WrongNumArgs(interp, 1, objv, "SUB-COMMAND ...");
+    return TCL_ERROR;
+  }
+  if( Tcl_GetIndexFromObj(interp, objv[1], strs, "sub-command", 0, &iSub) ){
+    return TCL_ERROR;
+  }
+
+  switch( (enum VL_enum)iSub ){
+    case VL_ANNOTATE: {
+      int rc;
+      char *zVfs;
+      char *zMsg;
+      if( objc!=4 ){
+        Tcl_WrongNumArgs(interp, 3, objv, "VFS");
+        return TCL_ERROR;
+      }
+      zVfs = Tcl_GetString(objv[2]);
+      zMsg = Tcl_GetString(objv[3]);
+      rc = sqlite3_vfslog_annotate(zVfs, zMsg);
+      if( rc!=SQLITE_OK ){
+        Tcl_AppendResult(interp, "failed", 0);
+        return TCL_ERROR;
+      }
+      break;
+    }
+    case VL_FINALIZE: {
+      int rc;
+      char *zVfs;
+      if( objc!=3 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "VFS");
+        return TCL_ERROR;
+      }
+      zVfs = Tcl_GetString(objv[2]);
+      rc = sqlite3_vfslog_finalize(zVfs);
+      if( rc!=SQLITE_OK ){
+        Tcl_AppendResult(interp, "failed", 0);
+        return TCL_ERROR;
+      }
+      break;
+    };
+
+    case VL_NEW: {
+      int rc;
+      char *zVfs;
+      char *zParent;
+      char *zLog;
+      if( objc!=5 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "VFS PARENT LOGFILE");
+        return TCL_ERROR;
+      }
+      zVfs = Tcl_GetString(objv[2]);
+      zParent = Tcl_GetString(objv[3]);
+      zLog = Tcl_GetString(objv[4]);
+      if( *zParent=='\0' ) zParent = 0;
+      rc = sqlite3_vfslog_new(zVfs, zParent, zLog);
+      if( rc!=SQLITE_OK ){
+        Tcl_AppendResult(interp, "failed", 0);
+        return TCL_ERROR;
+      }
+      break;
+    };
+
+    case VL_REGISTER: {
+      char *zDb;
+      if( objc!=3 ){
+        Tcl_WrongNumArgs(interp, 2, objv, "DB");
+        return TCL_ERROR;
+      }
+#ifdef SQLITE_OMIT_VIRTUALTABLE
+      Tcl_AppendResult(interp, "vfslog not available because of "
+                               "SQLITE_OMIT_VIRTUALTABLE", (void*)0);
+      return TCL_ERROR;
+#else
+      zDb = Tcl_GetString(objv[2]);
+      if( Tcl_GetCommandInfo(interp, zDb, &cmdInfo) ){
+        db = ((struct SqliteDb*)cmdInfo.objClientData)->db;
+        rc = sqlite3_vfslog_register(db);
+      }
+      if( rc!=SQLITE_OK ){
+        Tcl_AppendResult(interp, "bad sqlite3 handle: ", zDb, (void*)0);
+        return TCL_ERROR;
+      }
+      break;
+#endif
+    }
+  }
+
+  return TCL_OK;
+}
+
+int SqlitetestOsinst_Init(Tcl_Interp *interp){
+  Tcl_CreateObjCommand(interp, "vfslog", test_vfslog, 0, 0);
+  return TCL_OK;
+}
+
+#endif /* SQLITE_TEST */