XCURSOR_REFRESH() fixups/cleanup

* Check NUMKEYS(), similar to f34b61f947
  "ITS#8722 fix FIRST_DUP/LAST_DUP cursor bounds check".
* Move XCURSOR_INITED() into XCURSOR_REFRESH().  This adds a check in
  mdb_cursor_put, below /* converted, write the original data first */.
* Factor mc_ki[] out to XCURSOR_REFRESH().
* Replace an mc_pg[] with mp which is equal (mdb_cursor_del0).

libraries/liblmdb/mdb.c

@@ -1424,17 +1424,19 @@ typedef struct MDB_xcursor {
 	unsigned char mx_dbflag;
 } MDB_xcursor;
 
-	/** Check if there is an inited xcursor, so #XCURSOR_REFRESH() is proper */
+	/** Check if there is an inited xcursor */
 #define XCURSOR_INITED(mc) \
 	((mc)->mc_xcursor && ((mc)->mc_xcursor->mx_cursor.mc_flags & C_INITIALIZED))
 
-	/** Update sub-page pointer, if any, in \b mc->mc_xcursor.  Needed
+	/** Update the xcursor's sub-page pointer, if any, in \b mc.  Needed
 	 *	when the node which contains the sub-page may have moved.  Called
-	 *	with \b mp = mc->mc_pg[mc->mc_top], \b ki = mc->mc_ki[mc->mc_top].
+	 *	with leaf page \b mp = mc->mc_pg[\b top].
 	 */
-#define XCURSOR_REFRESH(mc, mp, ki) do { \
+#define XCURSOR_REFRESH(mc, top, mp) do { \
 	MDB_page *xr_pg = (mp); \
-	MDB_node *xr_node = NODEPTR(xr_pg, ki); \
+	MDB_node *xr_node; \
+	if (!XCURSOR_INITED(mc) || (mc)->mc_ki[top] >= NUMKEYS(xr_pg)) break; \
+	xr_node = NODEPTR(xr_pg, (mc)->mc_ki[top]); \
 	if ((xr_node->mn_flags & (F_DUPDATA|F_SUBDATA)) == F_DUPDATA) \
 		(mc)->mc_xcursor->mx_cursor.mc_pg[0] = NODEDATA(xr_node); \
 } while (0)
@@ -2773,8 +2775,8 @@ done:
 			if (m2 == mc) continue;
 			if (m2->mc_pg[mc->mc_top] == mp) {
 				m2->mc_pg[mc->mc_top] = np;
-				if (XCURSOR_INITED(m2) && IS_LEAF(np))
+				if (IS_LEAF(np))
-					XCURSOR_REFRESH(m2, np, m2->mc_ki[mc->mc_top]);
+					XCURSOR_REFRESH(m2, mc->mc_top, np);
 			}
 		}
 	}
@@ -7772,8 +7774,7 @@ new_sub:
 				if (m3->mc_ki[i] >= mc->mc_ki[i] && insert_key) {
 					m3->mc_ki[i]++;
 				}
-				if (XCURSOR_INITED(m3))
+				XCURSOR_REFRESH(m3, i, mp);
-					XCURSOR_REFRESH(m3, mp, m3->mc_ki[i]);
 			}
 		}
 	}
@@ -7815,7 +7816,6 @@ put_sub:
 				MDB_xcursor *mx = mc->mc_xcursor;
 				unsigned i = mc->mc_top;
 				MDB_page *mp = mc->mc_pg[i];
-				int nkeys = NUMKEYS(mp);
 
 				for (m2 = mc->mc_txn->mt_cursors[mc->mc_dbi]; m2; m2=m2->mc_next) {
 					if (m2 == mc || m2->mc_snum < mc->mc_snum) continue;
@@ -7823,8 +7823,8 @@ put_sub:
 					if (m2->mc_pg[i] == mp) {
 						if (m2->mc_ki[i] == mc->mc_ki[i]) {
 							mdb_xcursor_init2(m2, mx, new_dupdata);
-						} else if (!insert_key && m2->mc_ki[i] < nkeys) {
+						} else if (!insert_key) {
-							XCURSOR_REFRESH(m2, mp, m2->mc_ki[i]);
+							XCURSOR_REFRESH(m2, i, mp);
 						}
 					}
 				}
@@ -8787,8 +8787,8 @@ mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft)
 					m3->mc_ki[csrc->mc_top] = cdst->mc_ki[cdst->mc_top];
 					m3->mc_ki[csrc->mc_top-1]++;
 				}
-				if (XCURSOR_INITED(m3) && IS_LEAF(mps))
+				if (IS_LEAF(mps))
-					XCURSOR_REFRESH(m3, m3->mc_pg[csrc->mc_top], m3->mc_ki[csrc->mc_top]);
+					XCURSOR_REFRESH(m3, csrc->mc_top, m3->mc_pg[csrc->mc_top]);
 			}
 		} else
 		/* Adding on the right, bump others down */
@@ -8809,8 +8809,8 @@ mdb_node_move(MDB_cursor *csrc, MDB_cursor *cdst, int fromleft)
 					} else {
 						m3->mc_ki[csrc->mc_top]--;
 					}
-					if (XCURSOR_INITED(m3) && IS_LEAF(mps))
+					if (IS_LEAF(mps))
-						XCURSOR_REFRESH(m3, m3->mc_pg[csrc->mc_top], m3->mc_ki[csrc->mc_top]);
+						XCURSOR_REFRESH(m3, csrc->mc_top, m3->mc_pg[csrc->mc_top]);
 				}
 			}
 		}
@@ -9011,8 +9011,8 @@ mdb_page_merge(MDB_cursor *csrc, MDB_cursor *cdst)
 				m3->mc_ki[top-1] > csrc->mc_ki[top-1]) {
 				m3->mc_ki[top-1]--;
 			}
-			if (XCURSOR_INITED(m3) && IS_LEAF(psrc))
+			if (IS_LEAF(psrc))
-				XCURSOR_REFRESH(m3, m3->mc_pg[top], m3->mc_ki[top]);
+				XCURSOR_REFRESH(m3, top, m3->mc_pg[top]);
 		}
 	}
 	{
@@ -9275,8 +9275,7 @@ mdb_cursor_del0(MDB_cursor *mc)
 				} else if (m3->mc_ki[mc->mc_top] > ki) {
 					m3->mc_ki[mc->mc_top]--;
 				}
-				if (XCURSOR_INITED(m3))
+				XCURSOR_REFRESH(m3, mc->mc_top, mp);
-					XCURSOR_REFRESH(m3, m3->mc_pg[mc->mc_top], m3->mc_ki[mc->mc_top]);
 			}
 		}
 	}
@@ -9813,8 +9812,8 @@ mdb_page_split(MDB_cursor *mc, MDB_val *newkey, MDB_val *newdata, pgno_t newpgno
 				m3->mc_ki[ptop] >= mc->mc_ki[ptop]) {
 				m3->mc_ki[ptop]++;
 			}
-			if (XCURSOR_INITED(m3) && IS_LEAF(mp))
+			if (IS_LEAF(mp))
-				XCURSOR_REFRESH(m3, m3->mc_pg[mc->mc_top], m3->mc_ki[mc->mc_top]);
+				XCURSOR_REFRESH(m3, mc->mc_top, m3->mc_pg[mc->mc_top]);
 		}
 	}
 	DPRINTF(("mp left: %d, rp left: %d", SIZELEFT(mp), SIZELEFT(rp)));