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Diffstat (limited to 'db2/btree/bt_curadj.c')
-rw-r--r--db2/btree/bt_curadj.c272
1 files changed, 272 insertions, 0 deletions
diff --git a/db2/btree/bt_curadj.c b/db2/btree/bt_curadj.c
new file mode 100644
index 0000000000..9b86fbb6d7
--- /dev/null
+++ b/db2/btree/bt_curadj.c
@@ -0,0 +1,272 @@
+/*-
+ * See the file LICENSE for redistribution information.
+ *
+ * Copyright (c) 1996, 1997, 1998
+ *	Sleepycat Software.  All rights reserved.
+ */
+
+#include "config.h"
+
+#ifndef lint
+static const char sccsid[] = "@(#)bt_curadj.c	10.69 (Sleepycat) 12/2/98";
+#endif /* not lint */
+
+#ifndef NO_SYSTEM_INCLUDES
+#include <sys/types.h>
+
+#include <stdlib.h>
+#endif
+
+#include "db_int.h"
+#include "db_page.h"
+#include "btree.h"
+
+#ifdef DEBUG
+/*
+ * __bam_cprint --
+ *	Display the current cursor list.
+ *
+ * PUBLIC: int __bam_cprint __P((DB *));
+ */
+int
+__bam_cprint(dbp)
+	DB *dbp;
+{
+	CURSOR *cp;
+	DBC *dbc;
+
+	DB_THREAD_LOCK(dbp);
+	for (dbc = TAILQ_FIRST(&dbp->active_queue);
+	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
+		cp = (CURSOR *)dbc->internal;
+		fprintf(stderr,
+	    "%#0x->%#0x: page: %lu index: %lu dpage %lu dindex: %lu recno: %lu",
+		    (u_int)dbc, (u_int)cp, (u_long)cp->pgno, (u_long)cp->indx,
+		    (u_long)cp->dpgno, (u_long)cp->dindx, (u_long)cp->recno);
+		if (F_ISSET(cp, C_DELETED))
+			fprintf(stderr, " (deleted)");
+		fprintf(stderr, "\n");
+	}
+	DB_THREAD_UNLOCK(dbp);
+
+	return (0);
+}
+#endif /* DEBUG */
+
+/*
+ * __bam_ca_delete --
+ *	Update the cursors when items are deleted and when already deleted
+ *	items are overwritten.  Return the number of relevant cursors found.
+ *
+ * PUBLIC: int __bam_ca_delete __P((DB *, db_pgno_t, u_int32_t, int));
+ */
+int
+__bam_ca_delete(dbp, pgno, indx, delete)
+	DB *dbp;
+	db_pgno_t pgno;
+	u_int32_t indx;
+	int delete;
+{
+	DBC *dbc;
+	CURSOR *cp;
+	int count;		/* !!!: Has to contain max number of cursors. */
+
+	/* Recno is responsible for its own adjustments. */
+	if (dbp->type == DB_RECNO)
+		return (0);
+
+	/*
+	 * Adjust the cursors.  We don't have to review the cursors for any
+	 * thread of control other than the current one, because we have the
+	 * page write locked at this point, and any other thread of control
+	 * had better be using a different locker ID, meaning only cursors in
+	 * our thread of control can be on the page.
+	 *
+	 * It's possible for multiple cursors within the thread to have write
+	 * locks on the same page, but, cursors within a thread must be single
+	 * threaded, so all we're locking here is the cursor linked list.
+	 */
+	DB_THREAD_LOCK(dbp);
+	for (count = 0, dbc = TAILQ_FIRST(&dbp->active_queue);
+	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
+		cp = (CURSOR *)dbc->internal;
+
+		if ((cp->pgno == pgno && cp->indx == indx) ||
+		    (cp->dpgno == pgno && cp->dindx == indx)) {
+			if (delete)
+				F_SET(cp, C_DELETED);
+			else
+				F_CLR(cp, C_DELETED);
+			++count;
+		}
+	}
+	DB_THREAD_UNLOCK(dbp);
+
+	return (count);
+}
+
+/*
+ * __bam_ca_di --
+ *	Adjust the cursors during a delete or insert.
+ *
+ * PUBLIC: void __bam_ca_di __P((DB *, db_pgno_t, u_int32_t, int));
+ */
+void
+__bam_ca_di(dbp, pgno, indx, adjust)
+	DB *dbp;
+	db_pgno_t pgno;
+	u_int32_t indx;
+	int adjust;
+{
+	CURSOR *cp;
+	DBC *dbc;
+
+	/* Recno is responsible for its own adjustments. */
+	if (dbp->type == DB_RECNO)
+		return;
+
+	/*
+	 * Adjust the cursors.  See the comment in __bam_ca_delete().
+	 */
+	DB_THREAD_LOCK(dbp);
+	for (dbc = TAILQ_FIRST(&dbp->active_queue);
+	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
+		cp = (CURSOR *)dbc->internal;
+		if (cp->pgno == pgno && cp->indx >= indx)
+			cp->indx += adjust;
+		if (cp->dpgno == pgno && cp->dindx >= indx)
+			cp->dindx += adjust;
+	}
+	DB_THREAD_UNLOCK(dbp);
+}
+
+/*
+ * __bam_ca_dup --
+ *	Adjust the cursors when moving items from a leaf page to a duplicates
+ *	page.
+ *
+ * PUBLIC: void __bam_ca_dup __P((DB *,
+ * PUBLIC:    db_pgno_t, u_int32_t, u_int32_t, db_pgno_t, u_int32_t));
+ */
+void
+__bam_ca_dup(dbp, fpgno, first, fi, tpgno, ti)
+	DB *dbp;
+	db_pgno_t fpgno, tpgno;
+	u_int32_t first, fi, ti;
+{
+	CURSOR *cp;
+	DBC *dbc;
+
+	/* Recno is responsible for its own adjustments. */
+	if (dbp->type == DB_RECNO)
+		return;
+
+	/*
+	 * Adjust the cursors.  See the comment in __bam_ca_delete().
+	 */
+	DB_THREAD_LOCK(dbp);
+	for (dbc = TAILQ_FIRST(&dbp->active_queue);
+	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
+		cp = (CURSOR *)dbc->internal;
+		/*
+		 * Ignore matching entries that have already been moved,
+		 * we move from the same location on the leaf page more
+		 * than once.
+		 */
+		if (cp->dpgno == PGNO_INVALID &&
+		    cp->pgno == fpgno && cp->indx == fi) {
+			cp->indx = first;
+			cp->dpgno = tpgno;
+			cp->dindx = ti;
+		}
+	}
+	DB_THREAD_UNLOCK(dbp);
+}
+
+/*
+ * __bam_ca_rsplit --
+ *	Adjust the cursors when doing reverse splits.
+ *
+ * PUBLIC: void __bam_ca_rsplit __P((DB *, db_pgno_t, db_pgno_t));
+ */
+void
+__bam_ca_rsplit(dbp, fpgno, tpgno)
+	DB *dbp;
+	db_pgno_t fpgno, tpgno;
+{
+	CURSOR *cp;
+	DBC *dbc;
+
+	/* Recno is responsible for its own adjustments. */
+	if (dbp->type == DB_RECNO)
+		return;
+
+	/*
+	 * Adjust the cursors.  See the comment in __bam_ca_delete().
+	 */
+	DB_THREAD_LOCK(dbp);
+	for (dbc = TAILQ_FIRST(&dbp->active_queue);
+	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
+		cp = (CURSOR *)dbc->internal;
+		if (cp->pgno == fpgno)
+			cp->pgno = tpgno;
+	}
+	DB_THREAD_UNLOCK(dbp);
+}
+
+/*
+ * __bam_ca_split --
+ *	Adjust the cursors when splitting a page.
+ *
+ * PUBLIC: void __bam_ca_split __P((DB *,
+ * PUBLIC:    db_pgno_t, db_pgno_t, db_pgno_t, u_int32_t, int));
+ */
+void
+__bam_ca_split(dbp, ppgno, lpgno, rpgno, split_indx, cleft)
+	DB *dbp;
+	db_pgno_t ppgno, lpgno, rpgno;
+	u_int32_t split_indx;
+	int cleft;
+{
+	DBC *dbc;
+	CURSOR *cp;
+
+	/* Recno is responsible for its own adjustments. */
+	if (dbp->type == DB_RECNO)
+		return;
+
+	/*
+	 * Adjust the cursors.  See the comment in __bam_ca_delete().
+	 *
+	 * If splitting the page that a cursor was on, the cursor has to be
+	 * adjusted to point to the same record as before the split.  Most
+	 * of the time we don't adjust pointers to the left page, because
+	 * we're going to copy its contents back over the original page.  If
+	 * the cursor is on the right page, it is decremented by the number of
+	 * records split to the left page.
+	 */
+	DB_THREAD_LOCK(dbp);
+	for (dbc = TAILQ_FIRST(&dbp->active_queue);
+	    dbc != NULL; dbc = TAILQ_NEXT(dbc, links)) {
+		cp = (CURSOR *)dbc->internal;
+		if (cp->pgno == ppgno) {
+			if (cp->indx < split_indx) {
+				if (cleft)
+					cp->pgno = lpgno;
+			} else {
+				cp->pgno = rpgno;
+				cp->indx -= split_indx;
+			}
+		}
+		if (cp->dpgno == ppgno) {
+			if (cp->dindx < split_indx) {
+				if (cleft)
+					cp->dpgno = lpgno;
+			} else {
+				cp->dpgno = rpgno;
+				cp->dindx -= split_indx;
+			}
+		}
+	}
+	DB_THREAD_UNLOCK(dbp);
+}
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