/*
- * Copyright 2015 Facebook, Inc.
+ * Copyright 2017 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* limitations under the License.
*/
-#ifndef FOLLY_MAPUTIL_H_
-#define FOLLY_MAPUTIL_H_
+#pragma once
#include <folly/Conv.h>
#include <folly/Optional.h>
return (pos != map.end() ? pos->second : dflt);
}
+/**
+ * Give a map and a key, return the value corresponding to the key in the map,
+ * or a given default value if the key doesn't exist in the map.
+ */
+template <
+ class Map,
+ typename Func,
+ typename = typename std::enable_if<std::is_convertible<
+ typename std::result_of<Func()>::type,
+ typename Map::mapped_type>::value>::type>
+typename Map::mapped_type
+get_default(const Map& map, const typename Map::key_type& key, Func&& dflt) {
+ auto pos = map.find(key);
+ return pos != map.end() ? pos->second : dflt();
+}
+
/**
* Given a map and a key, return the value corresponding to the key in the map,
* or throw an exception of the specified type.
*/
template <class E = std::out_of_range, class Map>
-typename Map::mapped_type get_or_throw(
- const Map& map, const typename Map::key_type& key,
+const typename Map::mapped_type& get_or_throw(
+ const Map& map,
+ const typename Map::key_type& key,
+ const std::string& exceptionStrPrefix = std::string()) {
+ auto pos = map.find(key);
+ if (pos != map.end()) {
+ return pos->second;
+ }
+ throw E(folly::to<std::string>(exceptionStrPrefix, key));
+}
+
+template <class E = std::out_of_range, class Map>
+typename Map::mapped_type& get_or_throw(
+ Map& map,
+ const typename Map::key_type& key,
const std::string& exceptionStrPrefix = std::string()) {
auto pos = map.find(key);
if (pos != map.end()) {
return (pos != map.end() ? pos->second : dflt);
}
+/**
+ * Given a map and a key, return a reference to the value corresponding to the
+ * key in the map, or the given default reference if the key doesn't exist in
+ * the map.
+ */
+template <
+ class Map,
+ typename Func,
+ typename = typename std::enable_if<std::is_convertible<
+ typename std::result_of<Func()>::type,
+ const typename Map::mapped_type&>::value>::type,
+ typename = typename std::enable_if<
+ std::is_reference<typename std::result_of<Func()>::type>::value>::type>
+const typename Map::mapped_type& get_ref_default(
+ const Map& map,
+ const typename Map::key_type& key,
+ Func&& dflt) {
+ auto pos = map.find(key);
+ return (pos != map.end() ? pos->second : dflt());
+}
+
/**
* Given a map and a key, return a pointer to the value corresponding to the
* key in the map, or nullptr if the key doesn't exist in the map.
}
} // namespace folly
-
-#endif /* FOLLY_MAPUTIL_H_ */