[libvirt] [PATCH v4 2/7] util: Refactor virHashForEach so it returns as soon as an iterator fails

[Erik Skultety]

The method will now return 0 on success and -1 on error, rather than number of
items which it iterated over before it returned back to the caller. Since the
only place where we actually check the number of elements iterated is in
virhashtest, return value of 0 and -1 can be a pretty accurate hint that it
iterated over all the items. However, if we really want to know the number of
items iterated over (like virhashtest does), a counter has to be provided
through opaque data to each iterator call. This patch adjusts return value of
virHashForEach, refactors the body, so it returns as soon as one of the
iterators fail and adjusts virhashtest to reflect these changes.

Signed-off-by: Erik Skultety <eskultet at redhat.com>
---
 src/util/virhash.c  | 23 +++++++++++++++--------
 src/util/virhash.h  |  2 +-
 tests/virhashtest.c | 35 ++++++++++++++---------------------
 3 files changed, 30 insertions(+), 30 deletions(-)

diff --git a/src/util/virhash.c b/src/util/virhash.c
index d6f208e..a8e0edf 100644
--- a/src/util/virhash.c
+++ b/src/util/virhash.c
@@ -579,13 +579,16 @@ virHashRemoveEntry(virHashTablePtr table, const void *name)
  * Iterates over every element in the hash table, invoking the
  * 'iter' callback. The callback is allowed to remove the current element
  * using virHashRemoveEntry but calling other virHash* functions is prohibited.
+ * If @iter fails and returns a negative value, the evaluation is stopped and -1
+ * is returned.
  *
- * Returns number of items iterated over upon completion, -1 on failure
+ * Returns 0 on success or -1 on failure.
  */
-ssize_t
+int
 virHashForEach(virHashTablePtr table, virHashIterator iter, void *data)
 {
-    size_t i, count = 0;
+    size_t i;
+    int ret = -1;
 
     if (table == NULL || iter == NULL)
         return -1;
@@ -599,20 +602,24 @@ virHashForEach(virHashTablePtr table, virHashIterator iter, void *data)
         virHashEntryPtr entry = table->table[i];
         while (entry) {
             virHashEntryPtr next = entry->next;
-
             table->current = entry;
-            iter(entry->payload, entry->name, data);
+            ret = iter(entry->payload, entry->name, data);
             table->current = NULL;
 
-            count++;
+            if (ret < 0)
+                goto cleanup;
+
             entry = next;
         }
     }
-    table->iterating = false;
 
-    return count;
+    ret = 0;
+ cleanup:
+    table->iterating = false;
+    return ret;
 }
 
+
 /**
  * virHashRemoveSet
  * @table: the hash table to process
diff --git a/src/util/virhash.h b/src/util/virhash.h
index ed6bba3..61c172b 100644
--- a/src/util/virhash.h
+++ b/src/util/virhash.h
@@ -191,7 +191,7 @@ bool virHashEqual(const virHashTable *table1,
 /*
  * Iterators
  */
-ssize_t virHashForEach(virHashTablePtr table, virHashIterator iter, void *data);
+int virHashForEach(virHashTablePtr table, virHashIterator iter, void *data);
 ssize_t virHashRemoveSet(virHashTablePtr table, virHashSearcher iter, const void *data);
 void *virHashSearch(const virHashTable *table, virHashSearcher iter,
                     const void *data);
diff --git a/tests/virhashtest.c b/tests/virhashtest.c
index 323c68e..e538ea4 100644
--- a/tests/virhashtest.c
+++ b/tests/virhashtest.c
@@ -61,24 +61,27 @@ testHashCheckForEachCount(void *payload ATTRIBUTE_UNUSED,
                           const void *name ATTRIBUTE_UNUSED,
                           void *data ATTRIBUTE_UNUSED)
 {
+    ssize_t *count = data;
+    *count += 1;
     return 0;
 }
 
 static int
-testHashCheckCount(virHashTablePtr hash, size_t count)
+testHashCheckCount(virHashTablePtr hash, int count)
 {
-    ssize_t iter_count = 0;
+    int iter_count = 0;
 
     if (virHashSize(hash) != count) {
         VIR_TEST_VERBOSE("\nhash contains %zu instead of %zu elements\n",
-                  (size_t)virHashSize(hash), count);
+                  (size_t)virHashSize(hash), (size_t)count);
         return -1;
     }
 
-    iter_count = virHashForEach(hash, testHashCheckForEachCount, NULL);
+    virHashForEach(hash, testHashCheckForEachCount, &iter_count);
     if (count != iter_count) {
-        VIR_TEST_VERBOSE("\nhash claims to have %zu elements but iteration finds %zu\n",
-                  count, (size_t)iter_count);
+        VIR_TEST_VERBOSE("\nhash claims to have %zu elements but iteration"
+                         "finds %zu\n",
+                  (size_t)count, (size_t)iter_count);
         return -1;
     }
 
@@ -88,7 +91,7 @@ testHashCheckCount(virHashTablePtr hash, size_t count)
 
 struct testInfo {
     void *data;
-    size_t count;
+    int count;
 };
 
 
@@ -250,18 +253,13 @@ testHashRemoveForEach(const void *data)
 {
     const struct testInfo *info = data;
     virHashTablePtr hash;
-    int count;
     int ret = -1;
 
     if (!(hash = testHashInit(0)))
         return -1;
 
-    count = virHashForEach(hash, (virHashIterator) info->data, hash);
-
-    if (count != ARRAY_CARDINALITY(uuids)) {
-        VIR_TEST_VERBOSE("\nvirHashForEach didn't go through all entries,"
-                  " %d != %zu\n",
-                  count, ARRAY_CARDINALITY(uuids));
+    if (virHashForEach(hash, (virHashIterator) info->data, hash)) {
+        VIR_TEST_VERBOSE("\nvirHashForEach didn't go through all entries");
         goto cleanup;
     }
 
@@ -343,18 +341,13 @@ static int
 testHashForEach(const void *data ATTRIBUTE_UNUSED)
 {
     virHashTablePtr hash;
-    int count;
     int ret = -1;
 
     if (!(hash = testHashInit(0)))
         return -1;
 
-    count = virHashForEach(hash, testHashForEachIter, hash);
-
-    if (count != ARRAY_CARDINALITY(uuids)) {
-        VIR_TEST_VERBOSE("\nvirHashForEach didn't go through all entries,"
-                  " %d != %zu\n",
-                  count, ARRAY_CARDINALITY(uuids));
+    if (virHashForEach(hash, testHashForEachIter, hash)) {
+        VIR_TEST_VERBOSE("\nvirHashForEach didn't go through all entries");
         goto cleanup;
     }
 
-- 
2.4.3