SQLite

/*
** 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.
**
*************************************************************************
** $Id: btree.c,v 1.87 2003/04/06 20:44:45 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.

  /* Clean  up and report errors.
  */
  sqliteFree(sCheck.anRef);
  return sCheck.zErrMsg;
}

/*
** Return the full pathname of the underlying database file.
*/
static const char *sqliteBtreeGetFilename(Btree *pBt){
  assert( pBt->pPager!=0 );
  return sqlitepager_filename(pBt->pPager);
}

/*
** Change the name of the underlying database file.
*/
static int sqliteBtreeChangeFilename(Btree *pBt, const char *zNew){
  return sqlitepager_rename(pBt->pPager, zNew);
}

/*
** The following tables contain pointers to all of the interface
** routines for this implementation of the B*Tree backend.  To
** substitute a different implemention of the backend, one has merely
** to provide pointers to alternative functions in similar tables.
*/
static BtOps sqliteBtreeOps = {
    sqliteBtreeClose,
    sqliteBtreeSetCacheSize,
    sqliteBtreeSetSafetyLevel,
    sqliteBtreeBeginTrans,
    sqliteBtreeCommit,
    sqliteBtreeRollback,
    sqliteBtreeBeginCkpt,
    sqliteBtreeCommitCkpt,
    sqliteBtreeRollbackCkpt,
    sqliteBtreeCreateTable,
    sqliteBtreeCreateIndex,
    sqliteBtreeDropTable,
    sqliteBtreeClearTable,
    sqliteBtreeCursor,
    sqliteBtreeGetMeta,
    sqliteBtreeUpdateMeta,
    sqliteBtreeIntegrityCheck,
    sqliteBtreeGetFilename,
    sqliteBtreeChangeFilename,
#ifdef SQLITE_TEST
    sqliteBtreePageDump,
    sqliteBtreePager
#endif
};

static BtCursorOps sqliteBtreeCursorOps = {
    sqliteBtreeMoveto,
    sqliteBtreeDelete,
    sqliteBtreeInsert,
    sqliteBtreeFirst,
    sqliteBtreeLast,
    sqliteBtreeNext,

**    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 1.30 2003/04/06 20:44:45 drh Exp $
*/
#ifndef _BTREE_H_
#define _BTREE_H_

/*
** Forward declarations of structure
*/
typedef struct Btree Btree;
typedef struct BtCursor BtCursor;
typedef struct BtOps BtOps;
typedef struct BtCursorOps BtCursorOps;


/*
** An instance of the following structure contains pointers to all
** methods against an open BTree.  Alternative BTree implementations
** (examples: file based versus in-memory) can be created by substituting
** different methods.  Users of the BTree cannot tell the difference.
**
** In C++ we could do this by defining a virtual base class and then
** creating subclasses for each different implementation.  But this is
** C not C++ so we have to be a little more explicit.
*/
struct BtOps {
    int (*Close)(Btree*);
    int (*SetCacheSize)(Btree*, int);
    int (*SetSafetyLevel)(Btree*, int);

    int (*BeginTrans)(Btree*);
    int (*Commit)(Btree*);
    int (*Rollback)(Btree*);
    int (*BeginCkpt)(Btree*);
    int (*CommitCkpt)(Btree*);
    int (*RollbackCkpt)(Btree*);

    int (*CreateTable)(Btree*, int*);
    int (*CreateIndex)(Btree*, int*);
    int (*DropTable)(Btree*, int);
    int (*ClearTable)(Btree*, int);

    int (*Cursor)(Btree*, int iTable, int wrFlag, BtCursor **ppCur);

    int (*GetMeta)(Btree*, int*);
    int (*UpdateMeta)(Btree*, int*);

    char *(*IntegrityCheck)(Btree*, int*, int);
    const char *(*GetFilename)(Btree*);
    int (*ChangeFilename)(Btree*, const char *zNew);
#ifdef SQLITE_TEST
    int (*PageDump)(Btree*, int, int);
    struct Pager *(*Pager)(Btree*);
#endif
};


/*
** An instance of this structure defines all of the methods that can
** be executed against a cursor.
*/
struct BtCursorOps {
    int (*Moveto)(BtCursor*, const void *pKey, int nKey, int *pRes);
    int (*Delete)(BtCursor*);
    int (*Insert)(BtCursor*, const void *pKey, int nKey,
                             const void *pData, int nData);
    int (*First)(BtCursor*, int *pRes);
    int (*Last)(BtCursor*, int *pRes);
    int (*Next)(BtCursor*, int *pRes);
    int (*Previous)(BtCursor*, int *pRes);
    int (*KeySize)(BtCursor*, int *pSize);
    int (*Key)(BtCursor*, int offset, int amt, char *zBuf);
    int (*KeyCompare)(BtCursor*, const void *pKey, int nKey,
                                 int nIgnore, int *pRes);
    int (*DataSize)(BtCursor*, int *pSize);
    int (*Data)(BtCursor*, int offset, int amt, char *zBuf);
    int (*CloseCursor)(BtCursor*);
#ifdef SQLITE_TEST
    int (*CursorDump)(BtCursor*, int*);
#endif
};


/*
** The number of 4-byte "meta" values contained on the first page of each
** database file.
*/
#define SQLITE_N_BTREE_META 10

int sqliteBtreeOpen(const char *zFilename, int mode, int nPg, Btree **ppBtree);

#if !defined(SQLITE_NO_BTREE_DEFS)
#define btOps(pBt) (*((BtOps **)(pBt)))
#define btCOps(pCur) (*((BtCursorOps **)(pCur)))

#define sqliteBtreeClose(pBt)              (btOps(pBt)->Close(pBt))

#define sqliteBtreeSetCacheSize(pBt, sz)   (btOps(pBt)->SetCacheSize(pBt, sz))

#define sqliteBtreeSetSafetyLevel(pBt, sl) (btOps(pBt)->SetSafetyLevel(pBt, sl))

#define sqliteBtreeBeginTrans(pBt)         (btOps(pBt)->BeginTrans(pBt))

#define sqliteBtreeCommit(pBt)             (btOps(pBt)->Commit(pBt))

#define sqliteBtreeRollback(pBt)           (btOps(pBt)->Rollback(pBt))

#define sqliteBtreeBeginCkpt(pBt)          (btOps(pBt)->BeginCkpt(pBt))

#define sqliteBtreeCommitCkpt(pBt)         (btOps(pBt)->CommitCkpt(pBt))

#define sqliteBtreeRollbackCkpt(pBt)       (btOps(pBt)->RollbackCkpt(pBt))

#define sqliteBtreeCreateTable(pBt,piTable)\
                (btOps(pBt)->CreateTable(pBt,piTable))
#define sqliteBtreeCreateIndex(pBt, piIndex)\
                (btOps(pBt)->CreateIndex(pBt, piIndex))
#define sqliteBtreeDropTable(pBt, iTable) (btOps(pBt)->DropTable(pBt, iTable))

#define sqliteBtreeClearTable(pBt, iTable)\
                (btOps(pBt)->ClearTable(pBt, iTable))
#define sqliteBtreeCursor(pBt, iTable, wrFlag, ppCur)\
                (btOps(pBt)->Cursor(pBt, iTable, wrFlag, ppCur))
#define sqliteBtreeMoveto(pCur, pKey, nKey, pRes)\
                (btCOps(pCur)->Moveto(pCur, pKey, nKey, pRes))
#define sqliteBtreeDelete(pCur)           (btCOps(pCur)->Delete(pCur))

#define sqliteBtreeInsert(pCur, pKey, nKey, pData, nData) \
                (btCOps(pCur)->Insert(pCur, pKey, nKey, pData, nData))
#define sqliteBtreeFirst(pCur, pRes)      (btCOps(pCur)->First(pCur, pRes))

#define sqliteBtreeLast(pCur, pRes)       (btCOps(pCur)->Last(pCur, pRes))

#define sqliteBtreeNext(pCur, pRes)       (btCOps(pCur)->Next(pCur, pRes))

#define sqliteBtreePrevious(pCur, pRes)   (btCOps(pCur)->Previous(pCur, pRes))

#define sqliteBtreeKeySize(pCur, pSize)   (btCOps(pCur)->KeySize(pCur, pSize) )

#define sqliteBtreeKey(pCur, offset, amt, zBuf)\
                (btCOps(pCur)->Key(pCur, offset, amt, zBuf))
#define sqliteBtreeKeyCompare(pCur, pKey, nKey, nIgnore, pRes)\
                (btCOps(pCur)->KeyCompare(pCur, pKey, nKey, nIgnore, pRes))
#define sqliteBtreeDataSize(pCur, pSize)  (btCOps(pCur)->DataSize(pCur, pSize))

#define sqliteBtreeData(pCur, offset, amt, zBuf)\
                (btCOps(pCur)->Data(pCur, offset, amt, zBuf))
#define sqliteBtreeCloseCursor(pCur)      (btCOps(pCur)->CloseCursor(pCur))

#define sqliteBtreeGetMeta(pBt, aMeta)    (btOps(pBt)->GetMeta(pBt, aMeta))

#define sqliteBtreeUpdateMeta(pBt, aMeta) (btOps(pBt)->UpdateMeta(pBt, aMeta))

#define sqliteBtreeIntegrityCheck(pBt, aRoot, nRoot)\
                (btOps(pBt)->IntegrityCheck(pBt, aRoot, nRoot))
#define sqliteBtreeGetFilename(pBt)       (btOps(pBt)->GetFilename(pBt))
#define sqliteBtreeChangeFilename(pBt, zNew)\
                (btOps(pBt)->ChangeFilename(pBt, zNew))
#endif

#ifdef SQLITE_TEST
#if !defined(SQLITE_NO_BTREE_DEFS)
#define sqliteBtreePageDump(pBt, pgno, recursive)\
                (btOps(pBt)->PageDump(pBt, pgno, recursive))
#define sqliteBtreeCursorDump(pCur, aResult)\
                (btCOps(pCur)->CursorDump(pCur, aResult))
#define sqliteBtreePager(pBt)             (btOps(pBt)->Pager(pBt))

#endif

int btree_native_byte_order;
#endif

#endif /* _BTREE_H_ */

#endif
}


/*
** Change the name of an existing file.
*/
int sqliteOsFileRename(const char *zOldName, const char *zNewName){
#if OS_UNIX
  if( link(zOldName, zNewName) ){
    return SQLITE_ERROR;
  }
  unlink(zOldName);
  return SQLITE_OK;
#endif

** The pager is used to access a database disk file.  It implements
** atomic commit and rollback through the use of a journal file that
** is separate from the database file.  The pager also implements file
** locking to prevent two processes from writing the same database
** file simultaneously, or one process from reading the database while
** another is writing.
**
** @(#) $Id: pager.c,v 1.80 2003/04/06 20:44:45 drh Exp $
*/
#include "os.h"         /* Must be first to enable large file support */
#include "sqliteInt.h"
#include "pager.h"
#include <assert.h>
#include <string.h>

  assert( pPager->journalOpen==0 );
  /* Temp files are automatically deleted by the OS
  ** if( pPager->tempFile ){
  **   sqliteOsDelete(pPager->zFilename);
  ** }
  */
  CLR_PAGER(pPager);
  if( pPager->zFilename!=(char*)&pPager[1] ){
    sqliteFree(pPager->zFilename);
    sqliteFree(pPager->zJournal);
  }
  sqliteFree(pPager);
  return SQLITE_OK;
}

/*
** Return the page number for the given page data.
*/

    sqlitepager_ckpt_commit(pPager);
  }else{
    rc = SQLITE_OK;
  }
  pPager->ckptAutoopen = 0;
  return rc;
}

/*
** Return the full pathname of the database file.
*/
const char *sqlitepager_filename(Pager *pPager){
  return pPager->zFilename;
}

/*
** Rename the database file
*/
int sqlitepager_rename(Pager *pPager, const char *zNewName){
  char *zNew;
  char *zJournal;
  int nName;
  int rc;

  nName = strlen(zNewName);
  zNew = sqliteMalloc( nName*2 + 30 );
  if( zNew==0 ){
    return SQLITE_NOMEM;
  }
  memcpy(zNew, zNewName, nName+1);
  zJournal = &zNew[nName+1];
  memcpy(zJournal, zNew, nName);
  strcpy(&zJournal[nName], "-journal");
  if( pPager->journalOpen ){
    rc = sqliteOsRename(pPager->zJournal, zJournal);
    if( rc ){
      sqliteFree(zNew);
      return rc;
    }
  }
  rc = sqliteOsRename(pPager->zFilename, zNew);
  if( rc ){
    sqliteFree(zNew);
    return rc;
  }
  if( pPager->zFilename!=(char*)&pPager[1] ){
    sqliteFree(pPager->zFilename);
  }
  pPager->zFilename = zNew;
  return SQLITE_OK;
}

#ifdef SQLITE_TEST
/*
** Print a listing of all referenced pages and their ref count.
*/
void sqlitepager_refdump(Pager *pPager){
  PgHdr *pPg;

**    May you share freely, never taking more than you give.
**
*************************************************************************
** This header file defines the interface that the sqlite page cache
** subsystem.  The page cache subsystem reads and writes a file a page
** at a time and provides a journal for rollback.
**
** @(#) $Id: pager.h,v 1.22 2003/04/06 20:44:45 drh Exp $
*/

/*
** The size of one page
**
** You can change this value to another (reasonable) power of two
** such as 512, 2048, 4096, or 8192 and things will still work.  But

int sqlitepager_ckpt_begin(Pager*);
int sqlitepager_ckpt_commit(Pager*);
int sqlitepager_ckpt_rollback(Pager*);
void sqlitepager_dont_rollback(void*);
void sqlitepager_dont_write(Pager*, Pgno);
int *sqlitepager_stats(Pager*);
void sqlitepager_set_safety_level(Pager*,int);
const char *sqlitepager_filename(Pager*);
int sqlitepager_rename(Pager*, const char *zNewName);

#ifdef SQLITE_TEST
void sqlitepager_refdump(Pager*);
int pager_refinfo_enable;
int journal_format;
#endif