sqliteint.h

sqlite数据库管理系统开放源码

/*
** 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 1.220.2.2 2005/06/06 15:07:03 drh Exp $
*/
#include "config.h"
#include "sqlite.h"
#include "hash.h"
#include "parse.h"
#include "btree.h"
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>

/*
** The maximum number of in-memory pages to use for the main database
** table and for temporary tables.
*/
#define MAX_PAGES   2000
#define TEMP_PAGES   500

/*
** If the following macro is set to 1, then NULL values are considered
** distinct for the SELECT DISTINCT statement and for UNION or EXCEPT
** compound queries.  No other SQL database engine (among those tested) 
** works this way except for OCELOT.  But the SQL92 spec implies that
** this is how things should work.
**
** If the following macro is set to 0, then NULLs are indistinct for
** SELECT DISTINCT and for UNION.
*/
#define NULL_ALWAYS_DISTINCT 0

/*
** If the following macro is set to 1, then NULL values are considered
** distinct when determining whether or not two entries are the same
** in a UNIQUE index.  This is the way PostgreSQL, Oracle, DB2, MySQL,
** OCELOT, and Firebird all work.  The SQL92 spec explicitly says this
** is the way things are suppose to work.
**
** If the following macro is set to 0, the NULLs are indistinct for
** a UNIQUE index.  In this mode, you can only have a single NULL entry
** for a column declared UNIQUE.  This is the way Informix and SQL Server
** work.
*/
#define NULL_DISTINCT_FOR_UNIQUE 1

/*
** The maximum number of attached databases.  This must be at least 2
** in order to support the main database file (0) and the file used to
** hold temporary tables (1).  And it must be less than 256 because
** an unsigned character is used to stored the database index.
*/
#define MAX_ATTACHED 10

/*
** The next macro is used to determine where TEMP tables and indices
** are stored.  Possible values:
**
**   0    Always use a temporary files
**   1    Use a file unless overridden by "PRAGMA temp_store"
**   2    Use memory unless overridden by "PRAGMA temp_store"
**   3    Always use memory
*/
#ifndef TEMP_STORE
# define TEMP_STORE 1
#endif

/*
** When building SQLite for embedded systems where memory is scarce,
** you can define one or more of the following macros to omit extra
** features of the library and thus keep the size of the library to
** a minimum.
*/
/* #define SQLITE_OMIT_AUTHORIZATION  1 */
/* #define SQLITE_OMIT_INMEMORYDB     1 */
/* #define SQLITE_OMIT_VACUUM         1 */
/* #define SQLITE_OMIT_DATETIME_FUNCS 1 */
/* #define SQLITE_OMIT_PROGRESS_CALLBACK 1 */

/*
** Integers of known sizes.  These typedefs might change for architectures
** where the sizes very.  Preprocessor macros are available so that the
** types can be conveniently redefined at compile-type.  Like this:
**
**         cc '-DUINTPTR_TYPE=long long int' ...
*/
#ifndef UINT32_TYPE
# define UINT32_TYPE unsigned int
#endif
#ifndef UINT16_TYPE
# define UINT16_TYPE unsigned short int
#endif
#ifndef INT16_TYPE
# define INT16_TYPE short int
#endif
#ifndef UINT8_TYPE
# define UINT8_TYPE unsigned char
#endif
#ifndef INT8_TYPE
# define INT8_TYPE signed char
#endif
#ifndef INTPTR_TYPE
# if SQLITE_PTR_SZ==4
#   define INTPTR_TYPE int
# else
#   define INTPTR_TYPE long long
# endif
#endif
typedef UINT32_TYPE u32;           /* 4-byte unsigned integer */
typedef UINT16_TYPE u16;           /* 2-byte unsigned integer */
typedef INT16_TYPE i16;            /* 2-byte signed integer */
typedef UINT8_TYPE u8;             /* 1-byte unsigned integer */
typedef UINT8_TYPE i8;             /* 1-byte signed integer */
typedef INTPTR_TYPE ptr;           /* Big enough to hold a pointer */
typedef unsigned INTPTR_TYPE uptr; /* Big enough to hold a pointer */

/*
** Defer sourcing vdbe.h until after the "u8" typedef is defined.
*/
#include "vdbe.h"

/*
** Most C compilers these days recognize "long double", don't they?
** Just in case we encounter one that does not, we will create a macro
** for long double so that it can be easily changed to just "double".
*/
#ifndef LONGDOUBLE_TYPE
# define LONGDOUBLE_TYPE long double
#endif

/*
** This macro casts a pointer to an integer.  Useful for doing
** pointer arithmetic.
*/
#define Addr(X)  ((uptr)X)

/*
** The maximum number of bytes of data that can be put into a single
** row of a single table.  The upper bound on this limit is 16777215
** bytes (or 16MB-1).  We have arbitrarily set the limit to just 1MB
** here because the overflow page chain is inefficient for really big
** records and we want to discourage people from thinking that 
** multi-megabyte records are OK.  If your needs are different, you can
** change this define and recompile to increase or decrease the record
** size.
**
** The 16777198 is computed as follows:  238 bytes of payload on the
** original pages plus 16448 overflow pages each holding 1020 bytes of
** data.
*/
#define MAX_BYTES_PER_ROW  1048576
/* #define MAX_BYTES_PER_ROW 16777198 */

/*
** If memory allocation problems are found, recompile with
**
**      -DMEMORY_DEBUG=1
**
** to enable some sanity checking on malloc() and free().  To
** check for memory leaks, recompile with
**
**      -DMEMORY_DEBUG=2
**
** and a line of text will be written to standard error for
** each malloc() and free().  This output can be analyzed
** by an AWK script to determine if there are any leaks.
*/
#ifdef MEMORY_DEBUG
# define sqliteMalloc(X)    sqliteMalloc_(X,1,__FILE__,__LINE__)
# define sqliteMallocRaw(X) sqliteMalloc_(X,0,__FILE__,__LINE__)
# define sqliteFree(X)      sqliteFree_(X,__FILE__,__LINE__)
# define sqliteRealloc(X,Y) sqliteRealloc_(X,Y,__FILE__,__LINE__)
# define sqliteStrDup(X)    sqliteStrDup_(X,__FILE__,__LINE__)
# define sqliteStrNDup(X,Y) sqliteStrNDup_(X,Y,__FILE__,__LINE__)
  void sqliteStrRealloc(char**);
#else
# define sqliteRealloc_(X,Y) sqliteRealloc(X,Y)
# define sqliteStrRealloc(X)
#endif

/*
** This variable gets set if malloc() ever fails.  After it gets set,
** the SQLite library shuts down permanently.
*/
extern int sqlite_malloc_failed;

/*
** The following global variables are used for testing and debugging
** only.  They only work if MEMORY_DEBUG is defined.
*/
#ifdef MEMORY_DEBUG
extern int sqlite_nMalloc;       /* Number of sqliteMalloc() calls */
extern int sqlite_nFree;         /* Number of sqliteFree() calls */
extern int sqlite_iMallocFail;   /* Fail sqliteMalloc() after this many calls */
#endif

/*
** Name of the master database table.  The master database table
** is a special table that holds the names and attributes of all
** user tables and indices.
*/
#define MASTER_NAME       "sqlite_master"
#define TEMP_MASTER_NAME  "sqlite_temp_master"

/*
** The name of the schema table.
*/
#define SCHEMA_TABLE(x)  (x?TEMP_MASTER_NAME:MASTER_NAME)

/*
** A convenience macro that returns the number of elements in
** an array.
*/
#define ArraySize(X)    (sizeof(X)/sizeof(X[0]))

/*
** Forward references to structures
*/
typedef struct Column Column;
typedef struct Table Table;
typedef struct Index Index;
typedef struct Instruction Instruction;
typedef struct Expr Expr;
typedef struct ExprList ExprList;
typedef struct Parse Parse;
typedef struct Token Token;
typedef struct IdList IdList;
typedef struct SrcList SrcList;
typedef struct WhereInfo WhereInfo;
typedef struct WhereLevel WhereLevel;
typedef struct Select Select;
typedef struct AggExpr AggExpr;
typedef struct FuncDef FuncDef;
typedef struct Trigger Trigger;
typedef struct TriggerStep TriggerStep;
typedef struct TriggerStack TriggerStack;
typedef struct FKey FKey;
typedef struct Db Db;
typedef struct AuthContext AuthContext;

/*
** Each database file to be accessed by the system is an instance
** of the following structure.  There are normally two of these structures
** in the sqlite.aDb[] array.  aDb[0] is the main database file and
** aDb[1] is the database file used to hold temporary tables.  Additional
** databases may be attached.
*/
struct Db {
  char *zName;         /* Name of this database */
  Btree *pBt;          /* The B*Tree structure for this database file */
  int schema_cookie;   /* Database schema version number for this file */
  Hash tblHash;        /* All tables indexed by name */
  Hash idxHash;        /* All (named) indices indexed by name */
  Hash trigHash;       /* All triggers indexed by name */
  Hash aFKey;          /* Foreign keys indexed by to-table */
  u8 inTrans;          /* 0: not writable.  1: Transaction.  2: Checkpoint */
  u16 flags;           /* Flags associated with this database */
  void *pAux;          /* Auxiliary data.  Usually NULL */
  void (*xFreeAux)(void*);  /* Routine to free pAux */
};

/*
** These macros can be used to test, set, or clear bits in the 
** Db.flags field.
*/
#define DbHasProperty(D,I,P)     (((D)->aDb[I].flags&(P))==(P))
#define DbHasAnyProperty(D,I,P)  (((D)->aDb[I].flags&(P))!=0)
#define DbSetProperty(D,I,P)     (D)->aDb[I].flags|=(P)
#define DbClearProperty(D,I,P)   (D)->aDb[I].flags&=~(P)

/*
** Allowed values for the DB.flags field.
**
** The DB_Locked flag is set when the first OP_Transaction or OP_Checkpoint
** opcode is emitted for a database.  This prevents multiple occurances
** of those opcodes for the same database in the same program.  Similarly,
** the DB_Cookie flag is set when the OP_VerifyCookie opcode is emitted,
** and prevents duplicate OP_VerifyCookies from taking up space and slowing
** down execution.
**
** The DB_SchemaLoaded flag is set after the database schema has been
** read into internal hash tables.
**
** DB_UnresetViews means that one or more views have column names that
** have been filled out.  If the schema changes, these column names might
** changes and so the view will need to be reset.
*/
#define DB_Locked          0x0001  /* OP_Transaction opcode has been emitted */
#define DB_Cookie          0x0002  /* OP_VerifyCookie opcode has been emiited */
#define DB_SchemaLoaded    0x0004  /* The schema has been loaded */
#define DB_UnresetViews    0x0008  /* Some views have defined column names */


/*
** Each database is an instance of the following structure.
**
** The sqlite.file_format is initialized by the database file
** and helps determines how the data in the database file is
** represented.  This field allows newer versions of the library
** to read and write older databases.  The various file formats
** are as follows:
**
**     file_format==1    Version 2.1.0.
**     file_format==2    Version 2.2.0. Add support for INTEGER PRIMARY KEY.
**     file_format==3    Version 2.6.0. Fix empty-string index bug.
**     file_format==4    Version 2.7.0. Add support for separate numeric and