SQLite

**
******************************************************************************
**
** 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.
*/


/*
** C interface:
**
**   sqlite3_instvfs_create()
**   sqlite3_instvfs_destroy()
**   sqlite3_instvfs_configure()
**
**   sqlite3_instvfs_reset()
**   sqlite3_instvfs_get()
**
**   sqlite3_instvfs_binarylog
**
** 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.
**

/*
** 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_GETTEMPNAME       10
#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

struct InstVfs {
  sqlite3_vfs base;
  sqlite3_vfs *pVfs;
  
  void *pClient;
  void (*xDel)(void *);
  void (*xCall)(void *, int, sqlite3_int64, const char *, int, int, sqlite3_int64);

  /* Counters */
  i64 aTime[OS_NUMEVENTS];
  int aCount[OS_NUMEVENTS];
};
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 flags;
};

/*
** Method declarations for inst_file.
*/
static int instClose(sqlite3_file*);
static int instRead(sqlite3_file*, void*, int iAmt, sqlite3_int64 iOfst);

** The following routine only works on pentium-class processors.
** It uses the RDTSC opcode to read the cycle count value out of the
** processor and returns that value.  This can be used for high-res
** profiling.
*/
#if defined(i386) || defined(__i386__) || defined(_M_IX86)
__inline__ unsigned long long int hwtime(void){
   unsigned int lo, hi;
   /* We cannot use "=A", since this would use %rax on x86_64 */
   __asm__ __volatile__ ("rdtsc" : "=a" (lo), "=d" (hi));


   return (unsigned long long int)hi << 32 | lo;
}
#else
  static unsigned long long int hwtime(void){ return 0; }
#endif

#define OS_TIME_IO(eEvent, A, B, Call) {     \
  inst_file *p = (inst_file *)pFile;         \
  InstVfs *pInstVfs = p->pInstVfs;           \
  int rc;                                    \
  i64 t = hwtime();                          \
  rc = Call;                                 \
  t = hwtime() - t;                          \
  pInstVfs->aTime[eEvent] += t;              \
  pInstVfs->aCount[eEvent] += 1;             \
  if( pInstVfs->xCall ){                     \
    pInstVfs->xCall(pInstVfs->pClient, eEvent, t, p->zName, p->flags, A, B); \
  }                                          \
  return rc;                                 \
}

#define OS_TIME_VFS(eEvent, Z, A, B, Call) {      \
  InstVfs *pInstVfs = (InstVfs *)pVfs;   \
  int rc;                                \
  i64 t = hwtime();                      \
  rc = Call;                             \
  t = hwtime() - t;                      \
  pInstVfs->aTime[eEvent] += t;          \
  pInstVfs->aCount[eEvent] += 1;         \
  if( pInstVfs->xCall ){                 \
    pInstVfs->xCall(pInstVfs->pClient, eEvent, t, Z, 0, A, B); \
  }                                      \
  return rc;                             \
}

/*
** Close an inst-file.
*/

  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;

  OS_TIME_VFS(OS_OPEN, zName, flags, 0,
    sqlite3OsOpen(REALVFS(pVfs), zName, p->pReal, flags, pOutFlags)
  );
}

/*

*/
static int instCurrentTime(sqlite3_vfs *pVfs, double *pTimeOut){
  OS_TIME_VFS( OS_CURRENTTIME, 0, 0, 0,
    sqlite3OsCurrentTime(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;

  }

  return (sqlite3_vfs *)p;
}

void sqlite3_instvfs_configure(
  sqlite3_vfs *pVfs,
  void (*xCall)(void*, int, sqlite3_int64, const char*, int, int, i64),
  void *pClient,
  void (*xDel)(void *)
){
  InstVfs *p = (InstVfs *)pVfs;
  assert( pVfs->xOpen==instOpen );
  if( p->xDel ){
    p->xDel(p->pClient);

    return;
  }

  *pzEvent = sqlite3_instvfs_name(eEvent);
  *pnClick = p->aTime[eEvent];
  *pnCall = p->aCount[eEvent];
}

#define BINARYLOG_BUFFERSIZE 1024

struct InstVfsBinaryLog {
  int nBuf;
  char *zBuf;
  sqlite3_int64 iOffset;
  sqlite3_file *pOut;
};
typedef struct InstVfsBinaryLog InstVfsBinaryLog;

static void put32bits(unsigned char *p, u32 v){
  p[0] = v>>24;
  p[1] = v>>16;
  p[2] = v>>8;
  p[3] = v;
}

static void binarylog_xcall(
  void *p,
  int eEvent,
  sqlite3_int64 nClick,
  const char *zName,
  int flags,
  int nByte,
  sqlite3_int64 iOffset
){
  InstVfsBinaryLog *pLog = (InstVfsBinaryLog *)p;
  unsigned char *zRec;
  if( (20+pLog->nBuf)>BINARYLOG_BUFFERSIZE ){
    sqlite3_file *pFile = pLog->pOut;
    pFile->pMethods->xWrite(pFile, pLog->zBuf, pLog->nBuf, pLog->iOffset);
    pLog->iOffset += pLog->nBuf;
    pLog->nBuf = 0;
  }
  zRec = (unsigned char *)&pLog->zBuf[pLog->nBuf];
  put32bits(&zRec[0], eEvent);
  put32bits(&zRec[4], (int)nClick);
  put32bits(&zRec[8], flags);
  put32bits(&zRec[12], nByte);
  put32bits(&zRec[16], (int)iOffset);
  pLog->nBuf += 20;
}

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 ){
    pFile->pMethods->xWrite(pFile, pLog->zBuf, pLog->nBuf, pLog->iOffset);
  }
  pFile->pMethods->xClose(pFile);
  sqlite3_free(pLog->zBuf);
  sqlite3_free(pLog);
}

sqlite3_vfs *sqlite3_instvfs_binarylog(
  const char *zVfs,
  const char *zParentVfs, 
  const char *zLog
){
  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->szOsFile;

  p = (InstVfsBinaryLog *)sqlite3_malloc(nByte);
  memset(p, 0, nByte);
  p->zBuf = sqlite3_malloc(BINARYLOG_BUFFERSIZE);
  p->pOut = (sqlite3_file *)&p[1];

  flags = SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_MASTER_JOURNAL;
  rc = pParent->xOpen(pParent, zLog, p->pOut, flags, &flags);
  if( rc==SQLITE_OK ){
    rc = p->pOut->pMethods->xWrite(p->pOut, "sqlite_ostrace1.....", 20, 0);
    p->iOffset = 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;
}

/**************************************************************************
***************************************************************************
** Tcl interface starts here.
*/
#if SQLITE_TEST

#include <tcl.h>

struct InstVfsCall {
  Tcl_Interp *interp;
  Tcl_Obj *pScript;
};
typedef struct InstVfsCall InstVfsCall;

static void test_instvfs_xcall(
  void *p,
  int eEvent,
  sqlite3_int64 nClick,
  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);

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", 0 };
  enum IV_enum { IV_CREATE, IV_DESTROY, IV_RESET, IV_REPORT, IV_CONFIGURE, IV_BINARYLOG };
  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;

        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;
      sqlite3_vfs *p;
      int isDefault = 0;
      if( objc>2 && 0==strcmp("-default", Tcl_GetString(objv[2])) ){
        isDefault = 1;
      }
      if( (objc-isDefault)!=4 ){
        Tcl_WrongNumArgs(interp, 2, objv, "?-default? NAME LOGFILE");
        return TCL_ERROR;
      }
      zName = Tcl_GetString(objv[2+isDefault]);
      zLog = Tcl_GetString(objv[3+isDefault]);
      p = sqlite3_instvfs_binarylog(zName, 0, zLog);
      if( !p ){
        Tcl_AppendResult(interp, "error creating vfs ", 0);
        return TCL_ERROR;
      }
      if( isDefault ){
        sqlite3_vfs_register(p, 1);
      }