/*

** 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 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 */

  int iDb;              /* Index of cursor database in db->aDb[] (or -1) */

  i64 lastRowid;        /* Last rowid 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 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 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 isTable;         /* True if a table requiring integer keys */

  Bool isIndex;         /* True if an index containing 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 */

  i64 seqCount;         /* Sequence counter */

  sqlite3_vtab_cursor *pVtabCursor;  /* The cursor for a virtual table */

  const sqlite3_module *pModule;     /* Module for cursor pVtabCursor */

  /* Cached information about the header for the data record that the

  ** cursor is currently pointing to.  Only valid if cacheValid is true.

  ** aRow might point to (ephemeral) data for the current row, or it might

  ** be NULL.

  */

  int 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 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

/*

** A value for Cursor.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.  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. Or FuncDef* when flags==MEM_Agg */

  double r;           /* Real value */

  char *z;            /* String or BLOB 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 */

  void (*xDel)(void *);  /* If not null, call this function to delete Mem.z */

  char zShort[NBFS];  /* Space for short strings */

};

typedef struct Mem Mem;

/* 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 */

#define MEM_Agg       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 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 */

};

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 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 */

  u8 isError;           /* Set to true for an error */

  CollSeq *pColl;       /* Collating sequence */

};

/*

** 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 FifoPage structure holds a single page of valves.  Pages are arranged

** in a list.

*/

typedef struct FifoPage FifoPage;

struct FifoPage {

  int nSlot;         /* Number of entries aSlot[] */

  int iWrite;        /* Push the next value into this entry in aSlot[] */

  int iRead;         /* Read the next value from this entry in aSlot[] */

  FifoPage *pNext;   /* Next page in the fifo */

  i64 aSlot[1];      /* One or more slots for rowid values */

};

/*

** The Fifo structure is typedef-ed in vdbeInt.h.  But the implementation

** of that structure is private to this file.

**

** The Fifo structure describes the entire fifo.  

*/

typedef struct Fifo Fifo;

struct Fifo {

  int nEntry;         /* Total number of entries */

  FifoPage *pFirst;   /* First page on the list */

  FifoPage *pLast;    /* Last page on the list */

};

/*

** 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 {

  i64 lastRowid;    /* Last insert rowid (sqlite3.lastRowid) */

  int nChange;      /* Statement changes (Vdbe.nChanges)     */

  Fifo sFifo;       /* 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.

**

** 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 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 */

  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 nCallback;          /* Number of callbacks invoked so far */

  int cacheCtr;           /* Cursor row cache generation counter */

  Fifo sFifo;             /* 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 */

  u8 minWriteFileFormat;  /* Minimum file format for writable database files */

  u8 inVtabMethod;        /* See comments above */

  int nChange;            /* Number of db changes made since last reset */

  i64 startTime;          /* Time when query started - used for profiling */

#ifdef SQLITE_SSE

  int fetchId;          /* Statement number used by sqlite3_fetch_statement */

  int lru;              /* Counter used for LRU cache replacement */

#endif

};

/*

** 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 *, Cursor*);

void sqliteVdbePopStack(Vdbe*,int);

int sqlite3VdbeCursorMoveto(Cursor*);

#if defined(SQLITE_DEBUG) || defined(VDBE_PROFILE)

void sqlite3VdbePrintOp(FILE*, int, Op*);

#endif

#ifdef SQLITE_DEBUG

void sqlite3VdbePrintSql(Vdbe*);

#endif

int sqlite3VdbeSerialTypeLen(u32);

u32 sqlite3VdbeSerialType(Mem*, int);

int sqlite3VdbeSerialPut(unsigned char*, Mem*, int);

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(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*);

void sqlite3VdbeIntegerAffinity(Mem*);

int sqlite3VdbeMemRealify(Mem*);

int sqlite3VdbeMemNumerify(Mem*);

int sqlite3VdbeMemFromBtree(BtCursor*,int,int,int,Mem*);

void sqlite3VdbeMemRelease(Mem *p);

int sqlite3VdbeMemFinalize(Mem*, FuncDef*);

#ifndef NDEBUG

void sqlite3VdbeMemSanity(Mem*);

int sqlite3VdbeOpcodeNoPush(u8);

#endif

int sqlite3VdbeMemTranslate(Mem*, u8);

void sqlite3VdbeMemPrettyPrint(Mem *pMem, char *zBuf);

int sqlite3VdbeMemHandleBom(Mem *pMem);

void sqlite3VdbeFifoInit(Fifo*);

int sqlite3VdbeFifoPush(Fifo*, i64);

int sqlite3VdbeFifoPop(Fifo*, i64*);

void sqlite3VdbeFifoClear(Fifo*);