SQLite

/*
** 2004 April 6
**
** 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.
**
*************************************************************************
** $Id: btree.c,v 1.160 2004/06/07 01:52:14 drh Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

/*
** The TRACE macro will print high-level status information about the
** btree operation when the global variable sqlite3_btree_trace is
** enabled.
*/
#if SQLITE_TEST
# define TRACE(X)   if( sqlite3_btree_trace )\
                        { sqlite3DebugPrintf X; fflush(stdout); }
#else
# define TRACE(X)
#endif
int sqlite3_btree_trace=0;  /* True to enable tracing */

/*
** Allocate a new page from the database file.

  return x;
}
static unsigned long long int g_start;
static unsigned int elapse;
#define TIMER_START       g_start=hwtime()
#define TIMER_END         elapse=hwtime()-g_start
#define SEEK(X)           last_page=(X)
#define TRACE1(X)         sqlite3DebugPrintf(X)
#define TRACE2(X,Y)       sqlite3DebugPrintf(X,Y)
#define TRACE3(X,Y,Z)     sqlite3DebugPrintf(X,Y,Z)
#define TRACE4(X,Y,Z,A)   sqlite3DebugPrintf(X,Y,Z,A)
#define TRACE5(X,Y,Z,A,B) sqlite3DebugPrintf(X,Y,Z,A,B)
#else
#define TIMER_START
#define TIMER_END
#define SEEK(X)
#define TRACE1(X)
#define TRACE2(X,Y)
#define TRACE3(X,Y,Z)

    }
    *pReadonly = 1;
  }else{
    *pReadonly = 0;
  }
  id->h = h;
  id->locktype = NO_LOCK;
  id->sharedLockByte = 0;
  OpenCounter(+1);
  TRACE3("OPEN R/W %d \"%s\"\n", h, zFilename);
  return SQLITE_OK;
}


/*

     NULL
  );
  if( h==INVALID_HANDLE_VALUE ){
    return SQLITE_CANTOPEN;
  }
  id->h = h;
  id->locktype = NO_LOCK;
  id->sharedLockByte = 0;
  OpenCounter(+1);
  TRACE3("OPEN EX %d \"%s\"\n", h, zFilename);
  return SQLITE_OK;
}

/*
** Attempt to open a new file for read-only access.

     NULL
  );
  if( h==INVALID_HANDLE_VALUE ){
    return SQLITE_CANTOPEN;
  }
  id->h = h;
  id->locktype = NO_LOCK;
  id->sharedLockByte = 0;
  OpenCounter(+1);
  TRACE3("OPEN RO %d \"%s\"\n", h, zFilename);
  return SQLITE_OK;
}

/*
** Attempt to open a file descriptor for the directory that contains a

  return SQLITE_OK; 
}

/*
** Close a file.
*/
int sqlite3OsClose(OsFile *id){
  TRACE2("CLOSE %d\n", id->h);
  CloseHandle(id->h);
  OpenCounter(-1);
  return SQLITE_OK;
}

/*
** Read data from a file into a buffer.  Return SQLITE_OK if all
** bytes were read successfully and SQLITE_IOERR if anything goes
** wrong.
*/
int sqlite3OsRead(OsFile *id, void *pBuf, int amt){
  DWORD got;
  SimulateIOError(SQLITE_IOERR);
  TRACE3("READ %d lock=%d\n", id->h, id->locktype);
  if( !ReadFile(id->h, pBuf, amt, &got, 0) ){
    got = 0;
  }
  if( got==(DWORD)amt ){
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR;
  }
}

/*
** Write data from a buffer into a file.  Return SQLITE_OK on success
** or some other error code on failure.
*/
int sqlite3OsWrite(OsFile *id, const void *pBuf, int amt){
  int rc;
  DWORD wrote;
  SimulateIOError(SQLITE_IOERR);
  TRACE3("WRITE %d lock=%d\n", id->h, id->locktype);
  while( amt>0 && (rc = WriteFile(id->h, pBuf, amt, &wrote, 0))!=0 && wrote>0 ){
    amt -= wrote;
    pBuf = &((char*)pBuf)[wrote];
  }
  if( !rc || amt>(int)wrote ){
    return SQLITE_FULL;
  }

  return SQLITE_OK;
}

/*
** Make sure all writes to a particular file are committed to disk.
*/
int sqlite3OsSync(OsFile *id){
  TRACE3("SYNC %d lock=%d\n", id->h, id->locktype);
  if( FlushFileBuffers(id->h) ){
    return SQLITE_OK;
  }else{
    return SQLITE_IOERR;
  }
}

**
** The following #defines specify the range of bytes used for locking.
** SHARED_SIZE is the number of bytes available in the pool from which
** a random byte is selected for a shared lock.  The pool of bytes for
** shared locks begins at SHARED_FIRST.  
*/
#define SHARED_SIZE       10238
#define SHARED_FIRST      (0x3fffffff - (SHARED_SIZE - 1))
#define RESERVED_BYTE     (SHARED_FIRST - 1)
#define PENDING_BYTE      (RESERVED_BYTE - 1)

/*
** Return true (non-zero) if we are running under WinNT, Win2K or WinXP.
** Return false (zero) for Win95, Win98, or WinME.
**

** appropriate lock already exists, this routine is a no-op.  Return
** SQLITE_OK on success and SQLITE_BUSY if another thread is already
** holding a conflicting lock.
*/
int sqlite3OsLock(OsFile *id, int locktype){
  int rc = SQLITE_OK;    /* Return code from subroutines */
  int res = 1;           /* Result of a windows lock call */
  int newLocktype;       /* Set id->locktype to this value before exiting */
  int gotPendingLock = 0;/* True if we acquired a PENDING lock this time */

  TRACE5("LOCK %d %d was %d(%d)\n",
          id->h, locktype, id->locktype, id->sharedLockByte);

  /* If there is already a lock of this type or more restrictive on the
  ** OsFile, do nothing. Don't use the end_lock: exit path, as
  ** sqlite3OsEnterMutex() hasn't been called yet.
  */
  if( id->locktype>=locktype ){
    return SQLITE_OK;
  }

  /* Lock the PENDING_LOCK byte if we need to acquire a PENDING lock or
  ** a SHARED lock.  If we are acquiring a SHARED lock, the acquisition of
  ** the PENDING_LOCK byte is temporary.
  */
  if( id->locktype==NO_LOCK
   || (locktype>=PENDING_LOCK && id->locktype<PENDING_LOCK)
  ){
    int cnt = 4;
    while( cnt-->0 && (res = LockFile(id->h, PENDING_BYTE, 0, 1, 0))==0 ){
      /* Try 4 times to get the pending lock.  The pending lock might be
      ** held by another reader process who will release it momentarily.
      */
      TRACE2("could not get a PENDING lock. cnt=%d\n", cnt);
      Sleep(1);
    }
    gotPendingLock = res;
  }

  /* Acquire a shared lock
  */
  if( locktype>=SHARED_LOCK && id->locktype<SHARED_LOCK && res ){
    if( isNT() ){
      res = getReadLock(id->h, SHARED_FIRST, SHARED_SIZE);
    }else{
      int lk;
      sqlite3Randomness(sizeof(lk), &lk);
      id->sharedLockByte = (lk & 0x7fffffff)%(SHARED_SIZE - 1);
      res = LockFile(id->h, SHARED_FIRST+id->sharedLockByte, 0, 1, 0);
    }
    if( res ){
      newLocktype = SHARED_LOCK;
    }
  }

  /* Acquire a RESERVED lock
  */
  if( locktype>=RESERVED_LOCK && id->locktype<RESERVED_LOCK && res ){
    res = LockFile(id->h, RESERVED_BYTE, 0, 1, 0);
    if( res ){
      newLocktype = RESERVED_LOCK;
    }
  }

  /* Acquire a PENDING lock
  */
  if( locktype>=PENDING_LOCK && res ){
    newLocktype = PENDING_LOCK;
    gotPendingLock = 0;
  }

  /* Acquire an EXCLUSIVE lock
  */
  if( locktype==EXCLUSIVE_LOCK && res ){
    if( id->locktype>=SHARED_LOCK ){
      res = unlockReadLock(id);
      TRACE2("unreadlock = %d\n", res);
    }
    if( res ){
      res = LockFile(id->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
    }else{
      TRACE2("LOCK FAILED due to failure to unlock read %d\n", id->h);
      res = 0;
    }
    if( res ){
      newLocktype = EXCLUSIVE_LOCK;
    }else{
      TRACE2("error-code = %d\n", GetLastError());
    }
  }

  /* If we are holding a PENDING lock that ought to be released, then
  ** release it now.
  */
  if( gotPendingLock && (res==0 || locktype<PENDING_LOCK) ){
    UnlockFile(id->h, PENDING_BYTE, 0, 1, 0);
  }

  /* Update the state of the lock has held in the file descriptor then
  ** return the appropriate result code.
  */
  if( res ){

    rc = SQLITE_OK;
  }else{
    TRACE4("LOCK FAILED %d trying for %d but got %d\n", id->h,
           locktype, newLocktype);
    rc = SQLITE_BUSY;
  }
  id->locktype = newLocktype;
  return rc;
}

/*
** This routine checks if there is a RESERVED lock held on the specified
** file by this or any other process. If such a lock is held, return
** non-zero, otherwise zero.
*/
int sqlite3OsCheckWriteLock(OsFile *id){
  int rc;
  if( id->locktype>=RESERVED_LOCK ){
    rc = 1;
  }else{
    rc = LockFile(id->h, RESERVED_BYTE, 0, 1, 0);
    if( rc ){
      UnlockFile(id->h, RESERVED_BYTE, 0, 1, 0);
    }
  }
  return 0;
}

/*
** Unlock the given file descriptor.  If the file descriptor was
** not previously locked, then this routine is a no-op.  If this
** library was compiled with large file support (LFS) but LFS is not
** available on the host, then an SQLITE_NOLFS is returned.
*/
int sqlite3OsUnlock(OsFile *id){
  int rc, type;
  TRACE4("UNLOCK %d was %d(%d)\n", id->h, id->locktype, id->sharedLockByte);
  type = id->locktype;
  if( type>=EXCLUSIVE_LOCK ){
    UnlockFile(id->h, SHARED_FIRST, 0, SHARED_SIZE, 0);
  }
  if( type>=PENDING_LOCK ){
    UnlockFile(id->h, PENDING_BYTE, 0, 1, 0);
  }
  if( type>=RESERVED_LOCK ){
    UnlockFile(id->h, RESERVED_BYTE, 0, 1, 0);
  }
  if( type>=SHARED_LOCK && type<EXCLUSIVE_LOCK ){
    unlockReadLock(id);
  }
  id->locktype = NO_LOCK;
  return SQLITE_OK;
}

/*

  va_start(ap,zFormat);
  z = base_vprintf(0, 0, zBuf, n, zFormat, ap);
  va_end(ap);
  return z;
}

#ifndef NDEBUG
/*
** A version of printf() that understands %lld.  Used for debugging.
** The printf() built into some versions of windows does not understand %lld
** and segfaults if you give it a long long int.
*/
void sqlite3DebugPrintf(const char *zFormat, ...){
  va_list ap;
  char zBuf[500];
  va_start(ap, zFormat);
  base_vprintf(0, 0, zBuf, sizeof(zBuf), zFormat, ap);
  va_end(ap);
  fprintf(stderr,"%s", zBuf);
}
#endif

/*
** The following four routines implement the varargs versions of the
** sqlite3_exec() and sqlite3_get_table() interfaces.  See the sqlite.h
** header files for a more detailed description of how these interfaces
** work.
**
** These routines are all just simple wrappers.

  int rc;

  zSql = sqlite3_vmprintf(sqlFormat, ap);
  rc = sqlite3_get_table(db, zSql, resultp, nrow, ncolumn, errmsg);
  free(zSql);
  return rc;
}

/*
** 2001 September 15
**
** 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.
**
*************************************************************************
** Internal interface definitions for SQLite.
**
** @(#) $Id: sqliteInt.h,v 1.270 2004/06/07 01:52:14 drh Exp $
*/
#include "config.h"
#include "sqlite3.h"
#include "hash.h"
#include "parse.h"
#include <stdio.h>
#include <stdlib.h>

  void *sqliteRealloc(void*,int);
  char *sqliteStrDup(const char*);
  char *sqliteStrNDup(const char*, int);
# define sqlite3CheckMemory(a,b)
#endif
char *sqlite3MPrintf(const char*, ...);
char *sqlite3VMPrintf(const char*, va_list);
void sqlite3DebugPrintf(const char*, ...);
void sqlite3SetString(char **, const char *, ...);
void sqlite3SetNString(char **, ...);
void sqlite3ErrorMsg(Parse*, const char*, ...);
void sqlite3Dequote(char*);
int sqlite3KeywordCode(const char*, int);
int sqlite3RunParser(Parse*, const char*, char **);
void sqlite3Exec(Parse*);

#    May you share freely, never taking more than you give.
#
#***********************************************************************
# This file implements regression tests for SQLite library.  The
# focus of this script is testing the ATTACH and DETACH commands
# and related functionality.
#
# $Id: attach.test,v 1.22 2004/06/07 01:52:15 drh Exp $
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

for {set i 2} {$i<=15} {incr i} {
  file delete -force test$i.db

  catchsql {SELECT * FROM t1}
} {1 {database is locked}}
do_test attach-3.15 {
  execsql COMMIT db2
  execsql {SELECT * FROM t1}
} {1 2 3 4}

#set btree_trace 1
#puts stderr "###################"; flush stderr
# Ticket #323
do_test attach-4.1 {
  execsql {DETACH db2}
  db2 close
  sqlite db2 test2.db
  execsql {
    CREATE TABLE t3(x,y);