/*
** 2003 September 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.
**
*************************************************************************
** 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.
*/
/*
** intToKey() and keyToInt() used to transform the rowid. But with
** the latest versions of the design they are no-ops.
*/
#define keyToInt(X) (X)
#define intToKey(X) (X)
/*
** The makefile scans the vdbe.c source file and creates the following
** array of string constants which are the names of all VDBE opcodes. This
** array is defined in a separate source code file named opcode.c which is
** automatically generated by the makefile.
*/
extern const char *sqlite3OpcodeNames[];
/*
** SQL is translated into a sequence of instructions to be
** executed by a virtual machine. Each instruction is an instance
** of the following structure.
*/
typedef struct VdbeOp Op;
/*
** Boolean values
*/
typedef unsigned char Bool;
/*
** A cursor is a pointer into a single BTree within a database file.
** The cursor can seek to a BTree entry with a particular key, or
** loop over all entries of the Btree. You can also insert new BTree
** entries or retrieve the key or data from the entry that the cursor
** is currently pointing to.
**
** Every cursor that the virtual machine has open is represented by an
** instance of the following structure.
**
** If the Cursor.isTriggerRow flag is set it means that this cursor is
** really a single row that represents the NEW or OLD pseudo-table of
** a row trigger. The data for the row is stored in Cursor.pData and
** the rowid is in Cursor.iKey.
*/
struct Cursor {
BtCursor *pCursor; /* The cursor structure of the backend */
i64 lastRecno; /* Last recno from a Next or NextIdx operation */
i64 nextRowid; /* Next rowid returned by OP_NewRowid */
Bool zeroed; /* True if zeroed out and ready for reuse */
Bool recnoIsValid; /* True if lastRecno is valid */
Bool keyAsData; /* The OP_Column command works on key instead of data */
Bool atFirst; /* True if pointing to first entry */
Bool useRandomRowid; /* Generate new record numbers semi-randomly */
Bool nullRow; /* True if pointing to a row with no data */
Bool nextRowidValid; /* True if the nextRowid field is valid */
Bool pseudoTable; /* This is a NEW or OLD pseudo-tables of a trigger */
Bool deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */
Bool intKey; /* True if the table requires integer keys */
Bool zeroData; /* True if table contains keys only - no data */
u8 bogusIncrKey; /* Something for pIncrKey to point to if pKeyInfo==0 */
i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
Btree *pBt; /* Separate file holding temporary table */
int nData; /* Number of bytes in pData */
char *pData; /* Data for a NEW or OLD pseudo-table */
i64 iKey; /* Key for the NEW or OLD pseudo-table row */
u8 *pIncrKey; /* Pointer to pKeyInfo->incrKey */
KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */
int nField; /* Number of fields in the header */
/* Cached information about the header for the data record that the
** cursor is currently pointing to. Only valid if cacheValid is true.
** zRow might point to (ephemeral) data for the current row, or it might
** be NULL. */
Bool cacheValid; /* True if the cache is valid */
int payloadSize; /* Total number of bytes in the record */
u32 *aType; /* Type values for all entries in the record */
u32 *aOffset; /* Cached offsets to the start of each columns data */
u8 *aRow; /* Data for the current row, if all on one page */
};
typedef struct Cursor Cursor;
/*
** Number of bytes of string storage space available to each stack
** layer without having to malloc. NBFS is short for Number of Bytes
** For Strings.
*/
#define NBFS 32
/*
** Internally, the vdbe manipulates nearly all SQL values as Mem
** structures. Each Mem struct may cache multiple representations (string,
** integer etc.) of the same value. A value (and therefore Mem structure)
** has the following properties:
**
** Each value has a manifest type. The manifest type of the value stored
** in a Mem struct is returned by the MemType(Mem*) macro. The type is
** one of SQLITE_NULL, SQLITE_INTEGER, SQLITE_REAL, SQLITE_TEXT or
** SQLITE_BLOB.
*/
struct Mem {
i64 i; /* Integer value */
int n; /* Number of characters in string value, including '\0' */
u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
u8 type; /* One of MEM_Null, MEM_Str, etc. */
u8 enc; /* TEXT_Utf8, TEXT_Utf16le, or TEXT_Utf16be */
double r; /* Real value */
char *z; /* String or BLOB value */
void (*xDel)(void *); /* If not null, call this function to delete Mem.z */
char zShort[NBFS]; /* Space for short strings */
};
typedef struct Mem Mem;
/*
** A sorter builds a list of elements to be sorted. Each element of
** the list is an instance of the following structure.
*/
typedef struct Sorter Sorter;
struct Sorter {
int nKey; /* Number of bytes in the key */
char *zKey; /* The key by which we will sort */
Mem data;
Sorter *pNext; /* Next in the list */
};
/*
** Number of buckets used for merge-sort.
*/
#define NSORT 30
/* One or more of the following flags are set to indicate the validOK
** representations of the value stored in the Mem struct.
**
** If the MEM_Null flag is set, then the value is an SQL NULL value.
** No other flags may be set in this case.
**
** If the MEM_Str flag is set then Mem.z points at a string representation.
** Usually this is encoded in the same unicode encoding as the main
** database (see below for exceptions). If the MEM_Term flag is also
** set, then the string is nul terminated. The MEM_Int and MEM_Real
** flags may coexist with the MEM_Str flag.
**
** Multiple of these values can appear in Mem.flags. But only one
** at a time can appear in Mem.type.
*/
#define MEM_Null 0x0001 /* Value is NULL */
#define MEM_Str 0x0002 /* Value is a string */
#define MEM_Int 0x0004 /* Value is an integer */
#define MEM_Real 0x0008 /* Value is a real number */
#define MEM_Blob 0x0010 /* Value is a BLOB */
/* Whenever Mem contains a valid string or blob representation, one of
** the following flags must be set to determine the memory management
** policy for Mem.z. The MEM_Term flag tells us whether or not the
** string is \000 or \u0000 terminated
*/
#define MEM_Term 0x0020 /* String rep is nul terminated */
#define MEM_Dyn 0x0040 /* Need to call sqliteFree() on Mem.z */
#define MEM_Static 0x0080 /* Mem.z points to a static string */
#define MEM_Ephem 0x0100 /* Mem.z points to an ephemeral string */
#define MEM_Short 0x0200 /* Mem.z points to Mem.zShort */
/* The following MEM_ value appears only in AggElem.aMem.s.flag fields.
** It indicates that the corresponding AggElem.aMem.z points to a
** aggregate function context that needs to be finalized.
*/
#define MEM_AggCtx 0x0400 /* Mem.z points to an agg function context */
/* A VdbeFunc is just a FuncDef (defined in sqliteInt.h) that contains
** additional information about auxiliary information bound to arguments
** of the function. This is used to implement the sqlite3_get_auxdata()
** and sqlite3_set_auxdata() APIs. The "auxdata" is some auxiliary data
** that can be associated with a constant argument to a function. This
** allows functions such as "regexp" to compile their constant regular
** expression argument once and reused the compiled code for multiple
** invocations.
*/
struct AuxData {
void *pAux; /* Aux data for the i-th argument */
void (*xDelete)(void *); /* Destructor for the aux data */
};
struct VdbeFunc {
FuncDef *pFunc; /* The definition of the function */
int nAux; /* Number of entries allocated for apAux[] */
struct AuxData
apAux[1]; /* One slot for each function argument */
};
typedef struct VdbeFunc VdbeFunc;
/*
** The "context" argument for a installable function. A pointer to an
** instance of this structure is the first argument to the routines used
** implement the SQL functions.
**
** There is a typedef for this structure in sqlite.h. So all routines,
** even the public interface to SQLite, can use a pointer to this structure.
** But this file is the only place where the internal details of this
** structure are known.
**
** This structure is defined inside of vdbe.c because it uses substructures
** (Mem) which are only defined there.
*/
struct sqlite3_context {
FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */
VdbeFunc *pVdbeFunc; /* Auxilary data, if created. */
Mem s; /* The return value is stored here */
void *pAgg; /* Aggregate context */
u8 isError; /* Set to true for an error */
int cnt; /* Number of times that the step function has been called */
CollSeq *pColl;
};
/*
** An Agg structure describes an Aggregator. Each Agg consists of
** zero or more Aggregator elements (AggElem). Each AggElem contains
** a key and one or more values. The values are used in processing
** aggregate functions in a SELECT. The key is used to implement
** the GROUP BY clause of a select.
*/
typedef struct Agg Agg;
typedef struct AggElem AggElem;
struct Agg {
int nMem; /* Number of values stored in each AggElem */
AggElem *pCurrent; /* The AggElem currently in focus */
FuncDef **apFunc; /* Information about aggregate functions */
Btree *pBtree; /* The tmp. btree used to group elements, if required. */
BtCursor *pCsr; /* Read/write cursor to the table in pBtree */
int nTab; /* Root page of the table in pBtree */
u8 searching; /* True between the first AggNext and AggReset */
};
struct AggElem {
char *zKey; /* The key to this AggElem */
int nKey; /* Number of bytes in the key, including '\0' at end */
Mem aMem[1]; /* The values for this AggElem */
};
/*
** A Set structure is used for quick testing to see if a value
** is part of a small set. Sets are used to implement code like
** this:
** x.y IN ('hi','hoo','hum')
*/
typedef struct Set Set;
struct Set {
Hash hash; /* A set is just a hash table */
HashElem *prev; /* Previously accessed hash elemen */
};
/*
** A Keylist is a bunch of keys into a table. The keylist can
** grow without bound. The keylist stores the ROWIDs of database
** records that need to be deleted or updated.
*/
typedef struct Keylist Keylist;
struct Keylist {
int nKey; /* Number of slots in aKey[] */
int nUsed; /* Next unwritten slot in aKey[] */
int nRead; /* Next unread slot in aKey[] */
Keylist *pNext; /* Next block of keys */
i64 aKey[1]; /* One or more keys. Extra space allocated as needed */
};
/*
** A Context stores the last insert rowid, the last statement change count,
** and the current statement change count (i.e. changes since last statement).
** The current keylist is also stored in the context.
** Elements of Context structure type make up the ContextStack, which is
** updated by the ContextPush and ContextPop opcodes (used by triggers).
** The context is pushed before executing a trigger a popped when the
** trigger finishes.
*/
typedef struct Context Context;
struct Context {
int lastRowid; /* Last insert rowid (sqlite3.lastRowid) */
int nChange; /* Statement changes (Vdbe.nChanges) */
Keylist *pList; /* Records that will participate in a DELETE or UPDATE */
};
/*
** An instance of the virtual machine. This structure contains the complete
** state of the virtual machine.
**
** The "sqlite3_stmt" structure pointer that is returned by sqlite3_compile()
** is really a pointer to an instance of this structure.
*/
struct Vdbe {
sqlite3 *db; /* The whole database */
Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
FILE *trace; /* Write an execution trace here, if not NULL */
int nOp; /* Number of instructions in the program */
int nOpAlloc; /* Number of slots allocated for aOp[] */
Op *aOp; /* Space to hold the virtual machine's program */
int nLabel; /* Number of labels used */
int nLabelAlloc; /* Number of slots allocated in aLabel[] */
int *aLabel; /* Space to hold the labels */
Mem *aStack; /* The operand stack, except string values */
Mem *pTos; /* Top entry in the operand stack */
Mem **apArg; /* Arguments to currently executing user function */
Mem *aColName; /* Column names to return */
int nCursor; /* Number of slots in apCsr[] */
Cursor **apCsr; /* One element of this array for each open cursor */
Sorter *pSort; /* A linked list of objects to be sorted */
int nVar; /* Number of entries in aVar[] */
Mem *aVar; /* Values for the OP_Variable opcode. */
char **azVar; /* Name of variables */
int okVar; /* True if azVar[] has been initialized */
int magic; /* Magic number for sanity checking */
int nMem; /* Number of memory locations currently allocated */
Mem *aMem; /* The memory locations */
int nAgg; /* Number of elements in apAgg */
Agg *apAgg; /* Array of aggregate contexts */
Agg *pAgg; /* Current aggregate context */
int nCallback; /* Number of callbacks invoked so far */
Keylist *pList; /* A list of ROWIDs */
int contextStackTop; /* Index of top element in the context stack */
int contextStackDepth; /* The size of the "context" stack */
Context *contextStack; /* Stack used by opcodes ContextPush & ContextPop*/
int pc; /* The program counter */
int rc; /* Value to return */
unsigned uniqueCnt; /* Used by OP_MakeRecord when P2!=0 */
int errorAction; /* Recovery action to do in case of an error */
int inTempTrans; /* True if temp database is transactioned */
int returnStack[100]; /* Return address stack for OP_Gosub & OP_Return */
int returnDepth; /* Next unused element in returnStack[] */
int nResColumn; /* Number of columns in one row of the result set */
char **azResColumn; /* Values for one row of result */
int popStack; /* Pop the stack this much on entry to VdbeExec() */
char *zErrMsg; /* Error message written here */
u8 resOnStack; /* True if there are result values on the stack */
u8 explain; /* True if EXPLAIN present on SQL command */
u8 changeCntOn; /* True to update the change-counter */
u8 aborted; /* True if ROLLBACK in another VM causes an abort */
u8 expired; /* True if the VM needs to be recompiled */
int nChange; /* Number of db changes made since last reset */
};
/*
** The following are allowed values for Vdbe.magic
*/
#define VDBE_MAGIC_INIT 0x26bceaa5 /* Building a VDBE program */
#define VDBE_MAGIC_RUN 0xbdf20da3 /* VDBE is ready to execute */
#define VDBE_MAGIC_HALT 0x519c2973 /* VDBE has completed execution */
#define VDBE_MAGIC_DEAD 0xb606c3c8 /* The VDBE has been deallocated */
/*
** Function prototypes
*/
void sqlite3VdbeFreeCursor(Cursor*);
void sqlite3VdbeSorterReset(Vdbe*);
int sqlite3VdbeAggReset(sqlite3*, Agg *, KeyInfo *);
void sqlite3VdbeKeylistFree(Keylist*);
void sqliteVdbePopStack(Vdbe*,int);
int sqlite3VdbeCursorMoveto(Cursor*);
#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
void sqlite3VdbePrintOp(FILE*, int, Op*);
#endif
/FONT>
#ifdef SQLITE_DEBUG
void sqlite3VdbePrintSql(Vdbe*);
#endif
/FONT>
int sqlite3VdbeSerialTypeLen(u32);
u32 sqlite3VdbeSerialType(Mem*);
int sqlite3VdbeSerialPut(unsigned char*, Mem*);
int sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
int sqlite3VdbeIdxKeyCompare(Cursor*, int , const unsigned char*, int*);
int sqlite3VdbeIdxRowid(BtCursor *, i64 *);
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
int sqlite3VdbeRecordCompare(void*,int,const void*,int, const void*);
int sqlite3VdbeIdxRowidLen(int,const u8*);
int sqlite3VdbeExec(Vdbe*);
int sqlite3VdbeList(Vdbe*);
int sqlite3VdbeHalt(Vdbe*);
int sqlite3VdbeChangeEncoding(Mem *, int);
int sqlite3VdbeMemCopy(Mem*, const Mem*);
void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
int sqlite3VdbeMemMove(Mem*, Mem*);
int sqlite3VdbeMemNulTerminate(Mem*);
int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
void sqlite3VdbeMemSetInt64(Mem*, i64);
void sqlite3VdbeMemSetDouble(Mem*, double);
void sqlite3VdbeMemSetNull(Mem*);
int sqlite3VdbeMemMakeWriteable(Mem*);
int sqlite3VdbeMemDynamicify(Mem*);
int sqlite3VdbeMemStringify(Mem*, int);
i64 sqlite3VdbeIntValue(Mem*);
int sqlite3VdbeMemIntegerify(Mem*);
double sqlite3VdbeRealValue(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
#ifndef NDEBUG
void sqlite3VdbeMemSanity(Mem*, u8);
int sqlite3VdbeOpcodeNoPush(u8);
#endif
/FONT>
int sqlite3VdbeMemTranslate(Mem*, u8);
void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf, int nBuf);
int sqlite3VdbeMemHandleBom(Mem *pMem); |
2005/5/9
vdbeInt.h
