From 7795b6a47b7af268ed64ce901fa1f2d9f1bee6d3 Mon Sep 17 00:00:00 2001
From: Nigel Stewart <nigels@nigels.com>
Date: Tue, 14 Jan 2025 16:56:41 +1000
Subject: [PATCH] C++17 std::filesystem::path support added (#447)

---
 include/cxxopts.hpp | 15 +++++++++
 test/options.cpp    | 75 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 90 insertions(+)

diff --git a/include/cxxopts.hpp b/include/cxxopts.hpp
index 2819f50..63d140d 100644
--- a/include/cxxopts.hpp
+++ b/include/cxxopts.hpp
@@ -73,6 +73,12 @@ THE SOFTWARE.
 #      define CXXOPTS_HAS_OPTIONAL
 #    endif
 #  endif
+#  if __has_include(<filesystem>)
+#    include <filesystem>
+#    ifdef __cpp_lib_filesystem
+#      define CXXOPTS_HAS_FILESYSTEM
+#    endif
+#  endif
 #endif
 
 #define CXXOPTS_FALLTHROUGH
@@ -1074,6 +1080,15 @@ parse_value(const std::string& text, std::optional<T>& value)
 }
 #endif
 
+#ifdef CXXOPTS_HAS_FILESYSTEM
+inline
+void
+parse_value(const std::string& text, std::filesystem::path& value)
+{
+  value.assign(text);
+}
+#endif
+
 inline
 void parse_value(const std::string& text, char& c)
 {
diff --git a/test/options.cpp b/test/options.cpp
index 8b99a5b..843f4ae 100644
--- a/test/options.cpp
+++ b/test/options.cpp
@@ -732,6 +732,27 @@ TEST_CASE("std::optional", "[optional]") {
 }
 #endif
 
+#ifdef CXXOPTS_HAS_FILESYSTEM
+TEST_CASE("std::filesystem::path", "[path]") {
+  std::filesystem::path path;
+  cxxopts::Options options("path", " - tests path");
+  options.add_options()
+    ("path", "a path", cxxopts::value<std::filesystem::path>(path));
+
+  Argv av({"path", "--path", "Hello World.txt"});
+
+  auto** argv = av.argv();
+  auto argc = av.argc();
+
+  REQUIRE(path.empty());
+
+  options.parse(argc, argv);
+
+  REQUIRE(!path.empty());
+  CHECK(path == "Hello World.txt");
+}
+#endif
+
 TEST_CASE("Unrecognised options", "[options]") {
   cxxopts::Options options("unknown_options", " - test unknown options");
 
@@ -877,6 +898,60 @@ TEST_CASE("Optional value", "[optional]")
 }
 #endif
 
+#ifdef CXXOPTS_HAS_OPTIONAL
+TEST_CASE("std::filesystem::path value", "[path]")
+{
+  cxxopts::Options options("options", "query as std::fileystem::path");
+  options.add_options()
+    ("a", "Path", cxxopts::value<std::filesystem::path>())
+    ("b", "Path", cxxopts::value<std::filesystem::path>())
+    ("c", "Path", cxxopts::value<std::filesystem::path>())
+    ("d", "Path", cxxopts::value<std::filesystem::path>())
+    ("e", "Path", cxxopts::value<std::filesystem::path>())
+    ;
+
+  SECTION("Available") {
+    Argv av({
+      "available",
+      "-a", "hello.txt",
+      "-b", "C:\\Users\\JoeCitizen\\hello world.txt",
+      "-c", "/home/joecitzen/hello world.txt",
+      "-d", "../world.txt"
+    });
+
+    auto** argv = av.argv();
+    auto argc = av.argc();
+
+    auto result = options.parse(argc, argv);
+
+    CHECK(result.as_optional<std::filesystem::path>("a"));
+    CHECK(result.as_optional<std::filesystem::path>("b"));
+    CHECK(result.as_optional<std::filesystem::path>("c"));
+    CHECK(result.as_optional<std::filesystem::path>("d"));
+    CHECK(!result.as_optional<std::filesystem::path>("e"));
+
+    CHECK(result.as_optional<std::filesystem::path>("a") == "hello.txt");
+    CHECK(result.as_optional<std::filesystem::path>("b") == "C:\\Users\\JoeCitizen\\hello world.txt");
+    CHECK(result.as_optional<std::filesystem::path>("c") == "/home/joecitzen/hello world.txt");
+    CHECK(result.as_optional<std::filesystem::path>("d") == "../world.txt");
+  }
+
+  SECTION("Unavailable") {
+    Argv av({
+      "unavailable"
+    });
+
+    auto** argv = av.argv();
+    auto argc = av.argc();
+
+    auto result = options.parse(argc, argv);
+
+    CHECK(!result.as_optional<std::filesystem::path>("a"));
+  }
+
+}
+#endif
+
 TEST_CASE("Initializer list with group", "[options]") {
   cxxopts::Options options("Initializer list group", " - test initializer list with group");