add SqlQuery options. (#17)

Summary:
Pull Request resolved: #17

X-link: facebook/hhvm#9396

Adds basic operator functions for implementing hash function for QueryOptions.

Reviewed By: aditya-jalan

Differential Revision: D48757065

fbshipit-source-id: a12a27125ba8a1ee7c8468e43bcd2f3a3731b88e

squangle/mysql_client/Query.h

@@ -116,6 +116,15 @@ class QueryOptions {
     return attributes_;
   }
 
+  bool operator==(const QueryOptions& other) const {
+    return attributes_ == other.attributes_;
+  }
+
+  std::size_t hashValue() const {
+    return folly::hash::commutative_hash_combine_range(
+        attributes_.begin(), attributes_.end());
+  }
+
  protected:
   QueryAttributes attributes_;
 };
@@ -610,4 +619,14 @@ inline std::ostream& operator<<(
 }
 } // namespace std
 
+namespace std {
+template <>
+struct hash<facebook::common::mysql_client::QueryOptions> {
+  std::size_t operator()(
+      const facebook::common::mysql_client::QueryOptions& opt) const {
+    return opt.hashValue();
+  }
+};
+} // namespace std
+
 #endif // COMMON_ASYNC_MYSQL_QUERY_H