SQLite

/*
** 2007 August 27
**
** 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: btmutex.c,v 1.15 2009/04/10 12:55:17 danielk1977 Exp $
**
** This file contains code used to implement mutexes on Btree objects.
** This code really belongs in btree.c.  But btree.c is getting too
** big and we want to break it down some.  This packaged seemed like
** a good breakout.
*/
#include "btreeInt.h"
#ifndef SQLITE_OMIT_SHARED_CACHE
#if SQLITE_THREADSAFE

/*
** Obtain the BtShared mutex associated with B-Tree handle p. Also,
** set BtShared.db to the database handle associated with p and the
** p->locked boolean to true.
*/
static void lockBtreeMutex(Btree *p){

    p->wantToLock--;
    if( p->wantToLock==0 && p->locked ){
      unlockBtreeMutex(p);
    }
  }
}

#else
void sqlite3BtreeEnter(Btree *p){
  p->pBt->db = p->db;
}
void sqlite3BtreeEnterAll(sqlite3 *db){
  int i;
  for(i=0; i<db->nDb; i++){
    Btree *p = db->aDb[i].pBt;
    if( p ){
      p->pBt->db = p->db;
    }
  }
}
#endif /* if SQLITE_THREADSAFE */
#endif /* ifndef SQLITE_OMIT_SHARED_CACHE */

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite B-Tree file
** subsystem.  See comments in the source code for a detailed description
** of what each interface routine does.
**
** @(#) $Id: btree.h,v 1.113 2009/04/10 12:55:17 danielk1977 Exp $
*/
#ifndef _BTREE_H_
#define _BTREE_H_

/* TODO: This definition is just included so other modules compile. It
** needs to be revisited.
*/

#endif

/*
** If we are not using shared cache, then there is no need to
** use mutexes to access the BtShared structures.  So make the
** Enter and Leave procedures no-ops.
*/
#ifndef SQLITE_OMIT_SHARED_CACHE
  void sqlite3BtreeEnter(Btree*);
  void sqlite3BtreeEnterAll(sqlite3*);
#else
# define sqlite3BtreeEnter(X) 
# define sqlite3BtreeEnterAll(X)
#endif

#if !defined(SQLITE_OMIT_SHARED_CACHE) && SQLITE_THREADSAFE
  void sqlite3BtreeLeave(Btree*);
  void sqlite3BtreeEnterCursor(BtCursor*);
  void sqlite3BtreeLeaveCursor(BtCursor*);


  void sqlite3BtreeLeaveAll(sqlite3*);

  void sqlite3BtreeMutexArrayEnter(BtreeMutexArray*);
  void sqlite3BtreeMutexArrayLeave(BtreeMutexArray*);
  void sqlite3BtreeMutexArrayInsert(BtreeMutexArray*, Btree*);



#ifndef NDEBUG
  /* These routines are used inside assert() statements only. */
  int sqlite3BtreeHoldsMutex(Btree*);
  int sqlite3BtreeHoldsAllMutexes(sqlite3*);
#endif
#else

# define sqlite3BtreeLeave(X)
# define sqlite3BtreeEnterCursor(X)
# define sqlite3BtreeLeaveCursor(X)


# define sqlite3BtreeLeaveAll(X)

# define sqlite3BtreeMutexArrayEnter(X)
# define sqlite3BtreeMutexArrayLeave(X)
# define sqlite3BtreeMutexArrayInsert(X,Y)

# define sqlite3BtreeHoldsMutex(X) 1
# define sqlite3BtreeHoldsAllMutexes(X) 1
#endif


#endif /* _BTREE_H_ */

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.832 2009/04/10 12:55:17 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test

#endif

  /* Temporary space into which to unpack a record. */
  char aTempRec[ROUND8(sizeof(UnpackedRecord)) + sizeof(Mem)*3 + 7];

  assert( p->magic==VDBE_MAGIC_RUN );  /* sqlite3_step() verifies this */
  assert( db->magic==SQLITE_MAGIC_BUSY );
  sqlite3VdbeMutexArrayEnter(p);
  if( p->rc==SQLITE_NOMEM ){
    /* This happens if a malloc() inside a call to sqlite3_column_text() or
    ** sqlite3_column_text16() failed.  */
    goto no_mem;
  }
  assert( p->rc==SQLITE_OK || p->rc==SQLITE_BUSY );
  p->rc = SQLITE_OK;

*************************************************************************
** This is the header file for information that is private to the
** VDBE.  This information used to all be at the top of the single
** source code file "vdbe.c".  When that file became too big (over
** 6000 lines long) it was split up into several smaller files and
** this header information was factored out.
**
** $Id: vdbeInt.h,v 1.167 2009/04/10 12:55:17 danielk1977 Exp $
*/
#ifndef _VDBEINT_H_
#define _VDBEINT_H_

/*
** intToKey() and keyToInt() used to transform the rowid.  But with
** the latest versions of the design they are no-ops.

const char *sqlite3OpcodeName(int);
int sqlite3VdbeOpcodeHasProperty(int, int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
#ifdef SQLITE_ENABLE_MEMORY_MANAGEMENT
int sqlite3VdbeReleaseBuffers(Vdbe *p);
#endif

#ifndef SQLITE_OMIT_SHARED_CACHE
void sqlite3VdbeMutexArrayEnter(Vdbe *p);
#else
# define sqlite3VdbeMutexArrayEnter(p)
#endif

int sqlite3VdbeMemTranslate(Mem*, u8);
#ifdef SQLITE_DEBUG
  void sqlite3VdbePrintSql(Vdbe*);
  void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
#endif
int sqlite3VdbeMemHandleBom(Mem *pMem);

**
*************************************************************************
** This file contains code used for creating, destroying, and populating
** a VDBE (or an "sqlite3_stmt" as it is known to the outside world.)  Prior
** to version 2.8.7, all this code was combined into the vdbe.c source file.
** But that file was getting too big so this subroutines were split out.
**
** $Id: vdbeaux.c,v 1.450 2009/04/10 12:55:17 danielk1977 Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"



/*

    }
    db->nStatement--;
    p->iStatement = 0;
  }
  return rc;
}

/*
** If SQLite is compiled to support shared-cache mode and to be threadsafe,
** this routine obtains the mutex associated with each BtShared structure
** that may be accessed by the VM passed as an argument. In doing so it
** sets the BtShared.db member of each of the BtShared structures, ensuring
** that the correct busy-handler callback is invoked if required.
**
** If SQLite is not threadsafe but does support shared-cache mode, then
** sqlite3BtreeEnterAll() is invoked to set the BtShared.db variables
** of all of BtShared structures accessible via the database handle 
** associated with the VM. Of course only a subset of these structures
** will be accessed by the VM, and we could use Vdbe.btreeMask to figure
** that subset out, but there is no advantage to doing so.
**
** If SQLite is not threadsafe and does not support shared-cache mode, this
** function is a no-op.
*/
#ifndef SQLITE_OMIT_SHARED_CACHE
void sqlite3VdbeMutexArrayEnter(Vdbe *p){
#if SQLITE_THREADSAFE
  sqlite3BtreeMutexArrayEnter(&p->aMutex);
#else
  sqlite3BtreeEnterAll(p->db);
#endif
}
#endif

/*
** This routine is called the when a VDBE tries to halt.  If the VDBE
** has made changes and is in autocommit mode, then commit those
** changes.  If a rollback is needed, then do the rollback.
**
** This routine is the only way to move the state of a VM from
** SQLITE_MAGIC_RUN to SQLITE_MAGIC_HALT.  It is harmless to

  /* No commit or rollback needed if the program never started */
  if( p->pc>=0 ){
    int mrc;   /* Primary error code from p->rc */
    int eStatementOp = 0;
    int isSpecialError;            /* Set to true if a 'special' error */

    /* Lock all btrees used by the statement */
    sqlite3VdbeMutexArrayEnter(p);

    /* Check for one of the special errors */
    mrc = p->rc & 0xff;
    isSpecialError = mrc==SQLITE_NOMEM || mrc==SQLITE_IOERR
                     || mrc==SQLITE_INTERRUPT || mrc==SQLITE_FULL;
    if( isSpecialError ){
      /* If the query was read-only, we need do no rollback at all. Otherwise,