Add utility method and tests

Summary:
This commit provides a utility template method to check if a map contains any
of a list of keys. The keys are provided using start/end pointers (iterator).
Included are a number of test cases to exercise the new code and validate the
implementation.

There is a need for these changes (in stacked commits).

Reviewed By: wez

Differential Revision: D6203377

fbshipit-source-id: 9afe0f0cf8a4d4a82e94009c53a500a67a159976

MapUtil.h

@@ -30,6 +30,17 @@ bool mapContainsAny(const Map& map, const Key& firstKey, Args... args) {
   return mapContainsAny(map, firstKey) || mapContainsAny(map, args...);
 }
 
+// Returns true if the map contains any of a list of passed keys
+template <typename Map, typename Iterator>
+bool mapContainsAnyOf(const Map& map, Iterator first, Iterator last) {
+  for (auto it = first; it != last; ++it) {
+    if (map.find(*it) != map.end()) {
+      return true;
+    }
+  }
+  return false;
+}
+
 // Returns Map[Key] or if it isn't present, returns a default value.
 // if the default isn't specified, returns a default-constructed value.
 template <class Map, typename Key = typename Map::key_type>

tests/MapUtilTest.cpp

@@ -9,6 +9,7 @@
 #include "thirdparty/tap.h"
 
 using watchman::mapContainsAny;
+using watchman::mapContainsAnyOf;
 
 void test_map_contains_any() {
   std::unordered_map<w_string, int> uMap = {
@@ -48,9 +49,73 @@ void test_map_contains_any() {
   ok(!mapContainsAny(eMap, "xcase1"), "mapContainsAny absent on empty mape");
 }
 
+void test_map_contains_any_of() {
+  std::unordered_map<w_string, int> uMap = {
+      {"one", 1}, {"two", 2}, {"three", 3}};
+
+  {
+    // Using iterator to do the lookup
+    std::unordered_set<w_string> kSet = {"one"};
+    ok(mapContainsAnyOf(uMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf single string present");
+
+    kSet.emplace("two");
+    ok(mapContainsAnyOf(uMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf two strings present");
+
+    kSet.emplace("three");
+    ok(mapContainsAnyOf(uMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf all strings present");
+  }
+  {
+    std::unordered_set<w_string> kSet = {"one", "xcase1", "xcase2", "xcase3"};
+    ok(mapContainsAnyOf(uMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf one of several strings present");
+
+    kSet.emplace("two");
+    ok(mapContainsAnyOf(uMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf two of several strings present");
+  }
+  {
+    std::unordered_set<w_string> kSet;
+    ok(!mapContainsAnyOf(uMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf empty set");
+
+    kSet.emplace("xcase1");
+    ok(!mapContainsAnyOf(uMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf single string absent");
+
+    kSet.emplace("xcase2");
+    ok(!mapContainsAnyOf(uMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf two strings absent");
+
+    kSet.emplace("xcase3");
+    ok(!mapContainsAnyOf(uMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf three strings absent");
+  }
+
+  // Empty map tests
+  {
+    std::unordered_map<w_string, w_string> eMap;
+
+    std::unordered_set<w_string> kSet;
+    ok(!mapContainsAnyOf(eMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf absent on empty map and set");
+
+    kSet.emplace("one");
+    ok(!mapContainsAnyOf(eMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf absent on empty map and non-empty set");
+
+    kSet.emplace("two");
+    ok(!mapContainsAnyOf(eMap, kSet.begin(), kSet.end()),
+       "mapContainsAnyOf absent on empty map and 2 item set");
+  }
+}
+
 int main(int, char**) {
-  plan_tests(10);
+  plan_tests(22);
   test_map_contains_any();
+  test_map_contains_any_of();
 
   return exit_status();
 }