OpenSolaris_b135/lib/libsqlite/src/vdbeInt.h
#pragma ident "%Z%%M% %I% %E% SMI"
/*
** 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.
*/
/*
** When converting from the native format to the key format and back
** again, in addition to changing the byte order we invert the high-order
** bit of the most significant byte. This causes negative numbers to
** sort before positive numbers in the memcmp() function.
*/
#define keyToInt(X) (sqliteVdbeByteSwap(X) ^ 0x80000000)
#define intToKey(X) (sqliteVdbeByteSwap((X) ^ 0x80000000))
/*
** The makefile scans this 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 char *sqliteOpcodeNames[];
/*
** 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 */
int lastRecno; /* Last recno from a Next or NextIdx operation */
int nextRowid; /* Next rowid returned by OP_NewRowid */
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 sqliteBtreeMoveto() is needed */
int movetoTarget; /* Argument to the deferred sqliteBtreeMoveto() */
Btree *pBt; /* Separate file holding temporary table */
int nData; /* Number of bytes in pData */
char *pData; /* Data for a NEW or OLD pseudo-table */
int iKey; /* Key for the NEW or OLD pseudo-table row */
};
typedef struct Cursor Cursor;
/*
** 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 */
int nData; /* Number of bytes in the data */
char *pData; /* The data associated with this key */
Sorter *pNext; /* Next in the list */
};
/*
** Number of buckets used for merge-sort.
*/
#define NSORT 30
/*
** 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
/*
** A single level of the stack or a single memory cell
** is an instance of the following structure.
*/
struct Mem {
int i; /* Integer value */
int n; /* Number of characters in string value, including '\0' */
int flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
double r; /* Real value */
char *z; /* String value */
char zShort[NBFS]; /* Space for short strings */
};
typedef struct Mem Mem;
/*
** Allowed values for Mem.flags
*/
#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_Dyn 0x0010 /* Need to call sqliteFree() on Mem.z */
#define MEM_Static 0x0020 /* Mem.z points to a static string */
#define MEM_Ephem 0x0040 /* Mem.z points to an ephemeral string */
#define MEM_Short 0x0080 /* 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 0x0100 /* Mem.z points to an agg function context */
/*
** 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 sqlite_func {
FuncDef *pFunc; /* Pointer to function information. MUST BE FIRST */
Mem s; /* The return value is stored here */
void *pAgg; /* Aggregate context */
u8 isError; /* Set to true for an error */
u8 isStep; /* Current in the step function */
int cnt; /* Number of times that the step function has been called */
};
/*
** 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 */
HashElem *pSearch; /* The hash element for pCurrent */
Hash hash; /* Hash table of all aggregate elements */
FuncDef **apFunc; /* Information about aggregate functions */
};
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 */
int 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).
** Elements of Context structure type make up the ContextStack, which is
** updated by the ContextPush and ContextPop opcodes (used by triggers)
*/
typedef struct Context Context;
struct Context {
int lastRowid; /* Last insert rowid (from db->lastRowid) */
int lsChange; /* Last statement change count (from db->lsChange) */
int csChange; /* Current statement change count (from db->csChange) */
};
/*
** An instance of the virtual machine. This structure contains the complete
** state of the virtual machine.
**
** The "sqlite_vm" structure pointer that is returned by sqlite_compile()
** is really a pointer to an instance of this structure.
*/
struct Vdbe {
sqlite *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 */
char **zArgv; /* Text values used by the callback */
char **azColName; /* Becomes the 4th parameter to callbacks */
int nCursor; /* Number of slots in aCsr[] */
Cursor *aCsr; /* One element of this array for each open cursor */
Sorter *pSort; /* A linked list of objects to be sorted */
FILE *pFile; /* At most one open file handler */
int nField; /* Number of file fields */
char **azField; /* Data for each file field */
int nVar; /* Number of entries in azVariable[] */
char **azVar; /* Values for the OP_Variable opcode */
int *anVar; /* Length of each value in azVariable[] */
u8 *abVar; /* TRUE if azVariable[i] needs to be sqliteFree()ed */
char *zLine; /* A single line from the input file */
int nLineAlloc; /* Number of spaces allocated for zLine */
int magic; /* Magic number for sanity checking */
int nMem; /* Number of memory locations currently allocated */
Mem *aMem; /* The memory locations */
Agg agg; /* Aggregate information */
int nSet; /* Number of sets allocated */
Set *aSet; /* An array of sets */
int nCallback; /* Number of callbacks invoked so far */
Keylist *pList; /* A list of ROWIDs */
int keylistStackDepth; /* The size of the "keylist" stack */
Keylist **keylistStack; /* The stack used by opcodes ListPush & ListPop */
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 undoTransOnError; /* If error, either ROLLBACK or COMMIT */
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 explain; /* True if EXPLAIN present on SQL command */
};
/*
** 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 sqliteVdbeCleanupCursor(Cursor*);
void sqliteVdbeSorterReset(Vdbe*);
void sqliteVdbeAggReset(Agg*);
void sqliteVdbeKeylistFree(Keylist*);
void sqliteVdbePopStack(Vdbe*,int);
int sqliteVdbeCursorMoveto(Cursor*);
int sqliteVdbeByteSwap(int);
#if !defined(NDEBUG) || defined(VDBE_PROFILE)
void sqliteVdbePrintOp(FILE*, int, Op*);
#endif