Improve the function extract_type_identifier (#2923)

Signed-off-by: Barry Xu <[email protected]>

Author: Barry-Xu-2018

rclcpp/src/rclcpp/typesupport_helpers.cpp

@@ -15,6 +15,7 @@
 
 #include "rclcpp/typesupport_helpers.hpp"
 
+#include <algorithm>
 #include <functional>
 #include <memory>
 #include <sstream>
@@ -73,6 +74,21 @@ const void * get_typesupport_handle_impl(
   }
 }
 
+// Trim leading and trailing whitespace from the string.
+std::string string_trim(std::string_view str_v)
+{
+  auto begin = std::find_if_not(str_v.begin(), str_v.end(), [](unsigned char ch) {
+        return std::isspace(ch);
+  });
+  auto end = std::find_if_not(str_v.rbegin(), str_v.rend(), [](unsigned char ch) {
+        return std::isspace(ch);
+  }).base();
+  if (begin >= end) {
+    return {};
+  }
+  return std::string(begin, end);
+}
+
 }  // anonymous namespace
 
 std::tuple<std::string, std::string, std::string>
@@ -82,6 +98,7 @@ extract_type_identifier(const std::string & full_type)
   auto sep_position_back = full_type.find_last_of(type_separator);
   auto sep_position_front = full_type.find_first_of(type_separator);
   if (sep_position_back == std::string::npos ||
+    sep_position_front == 0 ||
     sep_position_back == 0 ||
     sep_position_back == full_type.length() - 1)
   {
@@ -97,7 +114,8 @@ extract_type_identifier(const std::string & full_type)
   }
   std::string type_name = full_type.substr(sep_position_back + 1);
 
-  return std::make_tuple(package_name, middle_module, type_name);
+  return std::make_tuple(
+    string_trim(package_name), string_trim(middle_module), string_trim(type_name));
 }
 
 std::string get_typesupport_library_path(

rclcpp/test/rclcpp/test_typesupport_helpers.cpp

@@ -158,3 +158,15 @@ TEST(TypesupportHelpersTest, test_throw_exception_with_invalid_type) {
     rclcpp::get_action_typesupport_handle(invalid_type, "rosidl_typesupport_cpp", *library),
     std::runtime_error);
 }
+
+TEST(TypesupportHelpersTest, throws_exception_if_filetype_has_multiple_slashes_at_start) {
+  EXPECT_ANY_THROW(rclcpp::extract_type_identifier("//name_with_slashes_at_start"));
+}
+
+TEST(TypesupportHelpersTestV3, ProcessesValidTypeWithWhitespace) {
+  std::string package, middle, name;
+  std::tie(package, middle, name) = rclcpp::extract_type_identifier("   package/  name  ");
+  EXPECT_EQ(package, "package");
+  EXPECT_TRUE(middle.empty());
+  EXPECT_EQ(name, "name");
+}