1 files changed, 99 insertions, 0 deletions
diff --git a/ovsdb/query.c b/ovsdb/query.c
new file mode 100644
index 000000000..878ac5b2d
--- /dev/null
+++ b/ovsdb/query.c
@@ -0,0 +1,99 @@
+/* Copyright (c) 2009 Nicira Networks
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at:
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <config.h>
+
+#include "query.h"
+
+#include "column.h"
+#include "condition.h"
+#include "row.h"
+#include "table.h"
+
+void
+ovsdb_query(struct ovsdb_table *table, const struct ovsdb_condition *cnd,
+            bool (*output_row)(const struct ovsdb_row *, void *aux), void *aux)
+{
+    if (cnd->n_clauses > 0
+        && cnd->clauses[0].column->index == OVSDB_COL_UUID
+        && cnd->clauses[0].function == OVSDB_F_EQ) {
+        /* Optimize the case where the query has a clause of the form "uuid ==
+         * <some-uuid>", since we have an index on UUID. */
+        const struct ovsdb_row *row;
+
+        row = ovsdb_table_get_row(table, &cnd->clauses[0].arg.keys[0].uuid);
+        if (row && row->table == table && ovsdb_condition_evaluate(row, cnd)) {
+            output_row(row, aux);
+        }
+    } else {
+        /* Linear scan. */
+        const struct ovsdb_row *row, *next;
+
+        HMAP_FOR_EACH_SAFE (row, next, struct ovsdb_row, hmap_node,
+                            &table->rows) {
+            if (ovsdb_condition_evaluate(row, cnd) && !output_row(row, aux)) {
+                break;
+            }
+        }
+    }
+}
+
+static bool
+query_row_set_cb(const struct ovsdb_row *row, void *results_)
+{
+    struct ovsdb_row_set *results = results_;
+    ovsdb_row_set_add_row(results, row);
+    return true;
+}
+
+void
+ovsdb_query_row_set(struct ovsdb_table *table,
+                    const struct ovsdb_condition *condition,
+                    struct ovsdb_row_set *results)
+{
+    ovsdb_query(table, condition, query_row_set_cb, results);
+}
+
+static bool
+query_distinct_cb(const struct ovsdb_row *row, void *hash_)
+{
+    struct ovsdb_row_hash *hash = hash_;
+    ovsdb_row_hash_insert(hash, row);
+    return true;
+}
+
+void
+ovsdb_query_distinct(struct ovsdb_table *table,
+                     const struct ovsdb_condition *condition,
+                     const struct ovsdb_column_set *columns,
+                     struct ovsdb_row_set *results)
+{
+    if (!columns || ovsdb_column_set_contains(columns, OVSDB_COL_UUID)) {
+        /* All the result rows are guaranteed to be distinct anyway. */
+        return ovsdb_query_row_set(table, condition, results);
+    } else {
+        /* Use hash table to drop duplicates. */
+        struct ovsdb_row_hash_node *node;
+        struct ovsdb_row_hash hash;
+
+        ovsdb_row_hash_init(&hash, columns);
+        ovsdb_query(table, condition, query_distinct_cb, &hash);
+        HMAP_FOR_EACH (node, struct ovsdb_row_hash_node, hmap_node,
+                       &hash.rows) {
+            ovsdb_row_set_add_row(results, node->row);
+        }
+        ovsdb_row_hash_destroy(&hash, false);
+    }
+}