[svn-r10185] Purpose:

New feature & bug fix

Description:
    Allow NULL 'op' for find operations to easily query the existance of a
record for a key during H5B2_find() operations.

    Fix H5B2_neighbor() to work properly with empty B-tree

Platforms tested:
    FreeBSD 4.11 (sleipnir)
    Solaris 2.9 (shanti)

src/H5B2.c

@@ -2941,6 +2941,9 @@ done:
  *              OP_DATA pointer, to allow caller to return information about
  *              the record.
  *
+ *              If 'OP' is NULL, then this routine just returns "SUCCEED" when
+ *              a record is found.
+ *
  * Return:	Non-negative on success, negative on failure.
  *
  * Programmer:	Quincey Koziol
@@ -2969,7 +2972,6 @@ H5B2_find(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
     HDassert(f);
     HDassert(type);
     HDassert(H5F_addr_defined(addr));
-    HDassert(op);
 
     /* Look up the B-tree header */
     if (NULL == (bt2 = H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, type, NULL, H5AC_READ)))
@@ -3027,7 +3029,7 @@ H5B2_find(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
         } /* end if */
         else {
             /* Make callback for current record */
-            if ((op)(H5B2_INT_NREC(internal,shared,idx), op_data) <0) {
+            if ( op && (op)(H5B2_INT_NREC(internal,shared,idx), op_data) <0) {
                 /* Unlock current node */
                 if (H5AC_unprotect(f, dxpl_id, H5AC_BT2_INT, curr_node_ptr.addr, internal, H5AC__NO_FLAGS_SET) < 0)
                     HGOTO_ERROR(H5E_BTREE, H5E_CANTUNPROTECT, FAIL, "unable to release B-tree node")
@@ -3073,7 +3075,7 @@ H5B2_find(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
         } /* end if */
         else {
             /* Make callback for current record */
-            if ((op)(H5B2_LEAF_NREC(leaf,shared,idx), op_data) <0) {
+            if ( op && (op)(H5B2_LEAF_NREC(leaf,shared,idx), op_data) <0) {
                 /* Unlock current node */
                 if (H5AC_unprotect(f, dxpl_id, H5AC_BT2_LEAF, curr_node_ptr.addr, leaf, H5AC__NO_FLAGS_SET) < 0)
                     HGOTO_ERROR(H5E_BTREE, H5E_CANTUNPROTECT, FAIL, "unable to release B-tree node")
@@ -3902,6 +3904,10 @@ H5B2_neighbor(H5F_t *f, hid_t dxpl_id, const H5B2_class_t *type, haddr_t addr,
     if (NULL == (bt2 = H5AC_protect(f, dxpl_id, H5AC_BT2_HDR, addr, type, NULL, H5AC_READ)))
 	HGOTO_ERROR(H5E_BTREE, H5E_CANTPROTECT, FAIL, "unable to load B-tree header")
 
+    /* Check for empty tree */
+    if(!H5F_addr_defined(bt2->root.addr))
+        HGOTO_ERROR(H5E_BTREE, H5E_NOTFOUND, FAIL, "B-tree has no records")
+
     /* Attempt to find neighbor record in B-tree */
     if(bt2->depth>0) {
         if(H5B2_neighbor_internal(f, dxpl_id, bt2->shared, bt2->depth, &bt2->root, NULL, range, udata, op, op_data)<0)

test/btree2.c

@@ -223,10 +223,20 @@ test_insert_basic(hid_t fapl)
     /* Should fail */
     if(ret != FAIL) TEST_ERROR;
 
+    /* Try again with NULL 'op' */
+    H5E_BEGIN_TRY {
+	ret = H5B2_find(f, H5P_DATASET_XFER_DEFAULT, H5B2_TEST, bt2_addr, &idx, NULL, NULL);
+    } H5E_END_TRY;
+    /* Should fail */
+    if(ret != FAIL) TEST_ERROR;
+
     /* Attempt to find existant record in B-tree with 1 record */
     idx = 42;
     if(H5B2_find(f, H5P_DATASET_XFER_DEFAULT, H5B2_TEST, bt2_addr, &idx, find_cb, &idx)<0) TEST_ERROR;
 
+    /* Try again with NULL 'op' */
+    if(H5B2_find(f, H5P_DATASET_XFER_DEFAULT, H5B2_TEST, bt2_addr, &idx, NULL, NULL)<0) TEST_ERROR;
+
     /* Attempt to index non-existant record in B-tree with 1 record */
     idx = 0;
     H5E_BEGIN_TRY {