Ninja: Simplify cmGlobalNinjaGenerator::AddRule and HasRule methods

- Use `std::unordered_set` for the emitted rule register
- Use `std::unordered_map` for command length register

Source/cmGlobalNinjaGenerator.cxx

@@ -706,22 +706,20 @@ void cmGlobalNinjaGenerator::AddRule(
   const std::string& restat, bool generator)
 {
   // Do not add the same rule twice.
-  if (this->HasRule(name)) {
+  if (!this->Rules.insert(name).second) {
     return;
   }
-
-  this->Rules.insert(name);
+  // Store command length
+  this->RuleCmdLength[name] = static_cast<int>(command.size());
+  // Write rule
   cmGlobalNinjaGenerator::WriteRule(*this->RulesFileStream, name, command,
                                     description, comment, depfile, deptype,
                                     rspfile, rspcontent, restat, generator);
-
-  this->RuleCmdLength[name] = static_cast<int>(command.size());
 }
 
 bool cmGlobalNinjaGenerator::HasRule(const std::string& name)
 {
-  RulesSetType::const_iterator rule = this->Rules.find(name);
-  return (rule != this->Rules.end());
+  return (this->Rules.find(name) != this->Rules.end());
 }
 
 // Private virtual overrides

Source/cmGlobalNinjaGenerator.h

@@ -10,6 +10,7 @@
 #include <set>
 #include <string>
 #include <unordered_map>
+#include <unordered_set>
 #include <utility>
 #include <vector>
 
@@ -415,15 +416,11 @@ private:
   cmGeneratedFileStream* RulesFileStream;
   cmGeneratedFileStream* CompileCommandsStream;
 
-  /// The type used to store the set of rules added to the generated build
-  /// system.
-  typedef std::set<std::string> RulesSetType;
-
   /// The set of rules added to the generated build system.
-  RulesSetType Rules;
+  std::unordered_set<std::string> Rules;
 
   /// Length of rule command, used by rsp file evaluation
-  std::map<std::string, int> RuleCmdLength;
+  std::unordered_map<std::string, int> RuleCmdLength;
 
   /// The set of dependencies to add to the "all" target.
   cmNinjaDeps AllDependencies;