database/sqlite
1
0
Fork 0
mirror of https://github.com/sqlite/sqlite.git synced 2025-11-12 13:01:09 +03:00
Code Activity

Refactor the VdbeCursor object. It is now slightly smaller and faster and is

Browse Source 
easier to understand.

FossilOrigin-Name: 9b1d174d862500a627840008ffac4c8419dc97e2
This commit is contained in:
drh
2015-11-20 19:22:01 +00:00
parent 5f7dacb443
commit c960dcbace
7 changed files with 225 additions and 171 deletions
Download Patch File Download Diff File Expand all files Collapse all files

52
src/vdbeInt.h
View File

@@ -58,42 +58,48 @@ typedef struct Explain Explain;
/* Elements of the linked list at Vdbe.pAuxData */
typedef struct AuxData AuxData;
/* Types of VDBE cursors */
#define CURTYPE_BTREE 0
#define CURTYPE_SORTER 1
#define CURTYPE_VTAB 2
#define CURTYPE_PSEUDO 3
/*
** 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.
** A VdbeCursor is an superclass (a wrapper) for various cursor objects:
**
** Cursors can also point to virtual tables, sorters, or "pseudo-tables".
** A pseudo-table is a single-row table implemented by registers.
**
** Every cursor that the virtual machine has open is represented by an
** instance of the following structure.
** * A b-tree cursor
** - In the main database or in an ephemeral database
** - On either an index or a table
** * A sorter
** * A virtual table
** * A one-row "pseudotable" stored in a single register
*/
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 seekResult; /* Result of previous sqlite3BtreeMoveto() */
int pseudoTableReg; /* Register holding pseudotable content. */
i16 nField; /* Number of fields in the header */
u16 nHdrParsed; /* Number of header fields parsed so far */
#ifdef SQLITE_DEBUG
u8 seekOp; /* Most recent seek operation on this cursor */
#endif
u8 eCurType; /* One of the CURTYPE_* values above */
i8 iDb; /* Index of cursor database in db->aDb[] (or -1) */
u8 nullRow; /* True if pointing to a row with no data */
u8 deferredMoveto; /* A call to sqlite3BtreeMoveto() is needed */
u8 isTable; /* True for rowid tables. False for indexes */
#ifdef SQLITE_DEBUG
u8 seekOp; /* Most recent seek operation on this cursor */
#endif
Bool isEphemeral:1; /* True for an ephemeral table */
Bool useRandomRowid:1;/* Generate new record numbers semi-randomly */
Bool isTable:1; /* True if a table requiring integer keys */
Bool isOrdered:1; /* True if the underlying table is BTREE_UNORDERED */
Pgno pgnoRoot; /* Root page of the open btree cursor */
sqlite3_vtab_cursor *pVtabCursor; /* The cursor for a virtual table */
i16 nField; /* Number of fields in the header */
u16 nHdrParsed; /* Number of header fields parsed so far */
union {
BtCursor *pCursor; /* CURTYPE_BTREE. Btree cursor */
sqlite3_vtab_cursor *pVCur; /* CURTYPE_VTAB. Vtab cursor */
int pseudoTableReg; /* CURTYPE_PSEUDO. Reg holding content. */
VdbeSorter *pSorter; /* CURTYPE_SORTER. Sorter object */
} uc;
Btree *pBt; /* Separate file holding temporary table */
KeyInfo *pKeyInfo; /* Info about index keys needed by index cursors */
int seekResult; /* Result of previous sqlite3BtreeMoveto() */
i64 seqCount; /* Sequence counter */
i64 movetoTarget; /* Argument to the deferred sqlite3BtreeMoveto() */
VdbeSorter *pSorter; /* Sorter object for OP_SorterOpen cursors */
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
u64 maskUsed; /* Mask of columns used by this cursor */
#endif