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** 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.
#ifndef _VDBEINT_H_
#define _VDBEINT_H_
** 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.
struct VdbeCursor {
BtCursor *pCursor; /* The cursor structure of the backend */
Btree *pBt; /* Separate file holding temporary table */
KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */
int iDb; /* Index of cursor database in db->aDb[] (or -1) */
int pseudoTableReg; /* Register holding pseudotable content. */
int nField; /* Number of fields in the header */
Bool zeroed; /* True if zeroed out and ready for reuse */
Bool rowidIsValid; /* True if lastRowid is valid */
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 deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */
Bool isTable; /* True if a table requiring integer keys */
Bool isIndex; /* True if an index containing keys only - no data */
Bool isOrdered; /* True if the underlying table is BTREE_UNORDERED */
sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */
const sqlite3_module *pModule; /* Module for cursor pVtabCursor */
i64 seqCount; /* Sequence counter */
i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
i64 lastRowid; /* Last rowid from a Next or NextIdx operation */
/* Result of last sqlite3BtreeMoveto() done by an OP_NotExists or
** OP_IsUnique opcode on this cursor. */
int seekResult;
/* Cached information about the header for the data record that the
** cursor is currently pointing to. Only valid if cacheStatus matches
** Vdbe.cacheCtr. Vdbe.cacheCtr will never take on the value of
** CACHE_STALE and so setting cacheStatus=CACHE_STALE guarantees that
** the cache is out of date.
** aRow might point to (ephemeral) data for the current row, or it might
** be NULL.
u32 cacheStatus; /* Cache is valid if this matches Vdbe.cacheCtr */
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 VdbeCursor VdbeCursor;
** When a sub-program is executed (OP_Program), a structure of this type
** is allocated to store the current value of the program counter, as
** well as the current memory cell array and various other frame specific
** values stored in the Vdbe struct. When the sub-program is finished,
** these values are copied back to the Vdbe from the VdbeFrame structure,
** restoring the state of the VM to as it was before the sub-program
** began executing.
** The memory for a VdbeFrame object is allocated and managed by a memory
** cell in the parent (calling) frame. When the memory cell is deleted or
** overwritten, the VdbeFrame object is not freed immediately. Instead, it
** is linked into the Vdbe.pDelFrame list. The contents of the Vdbe.pDelFrame
** list is deleted when the VM is reset in VdbeHalt(). The reason for doing
** this instead of deleting the VdbeFrame immediately is to avoid recursive
** calls to sqlite3VdbeMemRelease() when the memory cells belonging to the
** child frame are released.
** The currently executing frame is stored in Vdbe.pFrame. Vdbe.pFrame is
** set to NULL if the currently executing frame is the main program.
typedef struct VdbeFrame VdbeFrame;
struct VdbeFrame {
Vdbe *v; /* VM this frame belongs to */
int pc; /* Program Counter in parent (calling) frame */
Op *aOp; /* Program instructions for parent frame */
int nOp; /* Size of aOp array */
Mem *aMem; /* Array of memory cells for parent frame */
int nMem; /* Number of entries in aMem */
VdbeCursor **apCsr; /* Array of Vdbe cursors for parent frame */
u16 nCursor; /* Number of entries in apCsr */
void *token; /* Copy of SubProgram.token */
int nChildMem; /* Number of memory cells for child frame */
int nChildCsr; /* Number of cursors for child frame */
i64 lastRowid; /* Last insert rowid (sqlite3.lastRowid) */
int nChange; /* Statement changes (Vdbe.nChanges) */
VdbeFrame *pParent; /* Parent of this frame, or NULL if parent is main */
#define VdbeFrameMem(p) ((Mem *)&((u8 *)p)[ROUND8(sizeof(VdbeFrame))])
** A value for VdbeCursor.cacheValid that means the cache is always invalid.
#define CACHE_STALE 0
** 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.
struct Mem {
sqlite3 *db; /* The associated database connection */
char *z; /* String or BLOB value */
double r; /* Real value */
union {
i64 i; /* Integer value used when MEM_Int is set in flags */
int nZero; /* Used when bit MEM_Zero is set in flags */
FuncDef *pDef; /* Used only when flags==MEM_Agg */
RowSet *pRowSet; /* Used only when flags==MEM_RowSet */
VdbeFrame *pFrame; /* Used when flags==MEM_Frame */
} u;
int n; /* Number of characters in string value, excluding '\0' */
u16 flags; /* Some combination of MEM_Null, MEM_Str, MEM_Dyn, etc. */
Mem *pScopyFrom; /* This Mem is a shallow copy of pScopyFrom */
void *pFiller; /* So that sizeof(Mem) is a multiple of 8 */
void (*xDel)(void *); /* If not null, call this function to delete Mem.z */
char *zMalloc; /* Dynamic buffer allocated by sqlite3_malloc() */
/* 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.
#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 */
#define MEM_RowSet 0x0020 /* Value is a RowSet object */
#define MEM_Frame 0x0040 /* Value is a VdbeFrame object */
#define MEM_Invalid 0x0080 /* Value is undefined */
#define MEM_TypeMask 0x00ff /* Mask of type bits */
/* 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 0x0200 /* String rep is nul terminated */
#define MEM_Dyn 0x0400 /* Need to call sqliteFree() on Mem.z */
#define MEM_Static 0x0800 /* Mem.z points to a static string */
#define MEM_Ephem 0x1000 /* Mem.z points to an ephemeral string */
#define MEM_Agg 0x2000 /* Mem.z points to an agg function context */
#define MEM_Zero 0x4000 /* Mem.i contains count of 0s appended to blob */
#undef MEM_Zero
#define MEM_Zero 0x0000
** Clear any existing type flags from a Mem and replace them with f
#define MemSetTypeFlag(p, f) \
((p)->flags = ((p)->flags&~(MEM_TypeMask|MEM_Zero))|f)
** Return true if a memory cell is not marked as invalid. This macro
** is for use inside assert() statements only.
#define memIsValid(M) ((M)->flags & MEM_Invalid)==0
/* 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 VdbeFunc {
FuncDef *pFunc; /* The definition of the function */
int nAux; /* Number of entries allocated for apAux[] */
struct AuxData {
void *pAux; /* Aux data for the i-th argument */
void (*xDelete)(void *); /* Destructor for the aux data */
} apAux[1]; /* One slot for each function argument */
** 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 vdbeInt.h 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 */
Mem *pMem; /* Memory cell used to store aggregate context */
int isError; /* Error code returned by the function. */
CollSeq *pColl; /* Collating sequence */
** 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_prepare()
** is really a pointer to an instance of this structure.
** The Vdbe.inVtabMethod variable is set to non-zero for the duration of
** any virtual table method invocations made by the vdbe program. It is
** set to 2 for xDestroy method calls and 1 for all other methods. This
** variable is used for two purposes: to allow xDestroy methods to execute
** "DROP TABLE" statements and to prevent some nasty side effects of
** malloc failure when SQLite is invoked recursively by a virtual table
** method function.
struct Vdbe {
sqlite3 *db; /* The database connection that owns this statement */
Op *aOp; /* Space to hold the virtual machine's program */
Mem *aMem; /* The memory locations */
Mem **apArg; /* Arguments to currently executing user function */
Mem *aColName; /* Column names to return */
Mem *pResultSet; /* Pointer to an array of results */
int nMem; /* Number of memory locations currently allocated */
int nOp; /* Number of instructions in the program */
int nOpAlloc; /* Number of slots allocated for aOp[] */
int nLabel; /* Number of labels used */
int nLabelAlloc; /* Number of slots allocated in aLabel[] */
int *aLabel; /* Space to hold the labels */
u16 nResColumn; /* Number of columns in one row of the result set */
u16 nCursor; /* Number of slots in apCsr[] */
u32 magic; /* Magic number for sanity checking */
char *zErrMsg; /* Error message written here */
Vdbe *pPrev,*pNext; /* Linked list of VDBEs with the same Vdbe.db */
VdbeCursor **apCsr; /* One element of this array for each open cursor */
Mem *aVar; /* Values for the OP_Variable opcode. */
char **azVar; /* Name of variables */
ynVar nVar; /* Number of entries in aVar[] */
u32 cacheCtr; /* VdbeCursor row cache generation counter */
int pc; /* The program counter */
int rc; /* Value to return */
u8 errorAction; /* Recovery action to do in case of an error */
u8 okVar; /* True if azVar[] has been initialized */
u8 explain; /* True if EXPLAIN present on SQL command */
u8 changeCntOn; /* True to update the change-counter */
u8 expired; /* True if the VM needs to be recompiled */
u8 runOnlyOnce; /* Automatically expire on reset */
u8 minWriteFileFormat; /* Minimum file format for writable database files */
u8 inVtabMethod; /* See comments above */
u8 usesStmtJournal; /* True if uses a statement journal */
u8 readOnly; /* True for read-only statements */
u8 isPrepareV2; /* True if prepared with prepare_v2() */
int nChange; /* Number of db changes made since last reset */
yDbMask btreeMask; /* Bitmask of db->aDb[] entries referenced */
yDbMask lockMask; /* Subset of btreeMask that requires a lock */
int iStatement; /* Statement number (or 0 if has not opened stmt) */
int aCounter[3]; /* Counters used by sqlite3_stmt_status() */
i64 startTime; /* Time when query started - used for profiling */
i64 nFkConstraint; /* Number of imm. FK constraints this VM */
i64 nStmtDefCons; /* Number of def. constraints when stmt started */
char *zSql; /* Text of the SQL statement that generated this */
void *pFree; /* Free this when deleting the vdbe */
FILE *trace; /* Write an execution trace here, if not NULL */
VdbeFrame *pFrame; /* Parent frame */
VdbeFrame *pDelFrame; /* List of frame objects to free on VM reset */
int nFrame; /* Number of frames in pFrame list */
u32 expmask; /* Binding to these vars invalidates VM */
SubProgram *pProgram; /* Linked list of all sub-programs used by VM */
** 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(Vdbe *, VdbeCursor*);
void sqliteVdbePopStack(Vdbe*,int);
int sqlite3VdbeCursorMoveto(VdbeCursor*);
#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)
void sqlite3VdbePrintOp(FILE*, int, Op*);
u32 sqlite3VdbeSerialTypeLen(u32);
u32 sqlite3VdbeSerialType(Mem*, int);
u32 sqlite3VdbeSerialPut(unsigned char*, int, Mem*, int);
u32 sqlite3VdbeSerialGet(const unsigned char*, u32, Mem*);
void sqlite3VdbeDeleteAuxData(VdbeFunc*, int);
int sqlite2BtreeKeyCompare(BtCursor *, const void *, int, int, int *);
int sqlite3VdbeIdxKeyCompare(VdbeCursor*,UnpackedRecord*,int*);
int sqlite3VdbeIdxRowid(sqlite3*, BtCursor *, i64 *);
int sqlite3MemCompare(const Mem*, const Mem*, const CollSeq*);
int sqlite3VdbeExec(Vdbe*);
int sqlite3VdbeList(Vdbe*);
int sqlite3VdbeHalt(Vdbe*);
int sqlite3VdbeChangeEncoding(Mem *, int);
int sqlite3VdbeMemTooBig(Mem*);
int sqlite3VdbeMemCopy(Mem*, const Mem*);
void sqlite3VdbeMemShallowCopy(Mem*, const Mem*, int);
void sqlite3VdbeMemMove(Mem*, Mem*);
int sqlite3VdbeMemNulTerminate(Mem*);
int sqlite3VdbeMemSetStr(Mem*, const char*, int, u8, void(*)(void*));
void sqlite3VdbeMemSetInt64(Mem*, i64);
# define sqlite3VdbeMemSetDouble sqlite3VdbeMemSetInt64
void sqlite3VdbeMemSetDouble(Mem*, double);
void sqlite3VdbeMemSetNull(Mem*);
void sqlite3VdbeMemSetZeroBlob(Mem*,int);
void sqlite3VdbeMemSetRowSet(Mem*);
int sqlite3VdbeMemMakeWriteable(Mem*);
int sqlite3VdbeMemStringify(Mem*, int);
i64 sqlite3VdbeIntValue(Mem*);
int sqlite3VdbeMemIntegerify(Mem*);
double sqlite3VdbeRealValue(Mem*);
void sqlite3VdbeIntegerAffinity(Mem*);
int sqlite3VdbeMemRealify(Mem*);
int sqlite3VdbeMemNumerify(Mem*);
int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);
void sqlite3VdbeMemRelease(Mem *p);
void sqlite3VdbeMemReleaseExternal(Mem *p);
int sqlite3VdbeMemFinalize(Mem*, FuncDef*);
const char *sqlite3OpcodeName(int);
int sqlite3VdbeMemGrow(Mem *pMem, int n, int preserve);
int sqlite3VdbeCloseStatement(Vdbe *, int);
void sqlite3VdbeFrameDelete(VdbeFrame*);
int sqlite3VdbeFrameRestore(VdbeFrame *);
void sqlite3VdbeMemStoreType(Mem *pMem);
void sqlite3VdbeEnter(Vdbe*);
void sqlite3VdbeLeave(Vdbe*);
# define sqlite3VdbeEnter(X)
# define sqlite3VdbeLeave(X)
void sqlite3VdbeMemPrepareToChange(Vdbe*,Mem*);
int sqlite3VdbeCheckFk(Vdbe *, int);
# define sqlite3VdbeCheckFk(p,i) 0
int sqlite3VdbeMemTranslate(Mem*, u8);
void sqlite3VdbePrintSql(Vdbe*);
void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);
int sqlite3VdbeMemHandleBom(Mem *pMem);
int sqlite3VdbeMemExpandBlob(Mem *);
#define sqlite3VdbeMemExpandBlob(x) SQLITE_OK
#endif /* !defined(_VDBEINT_H_) */