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// This source code is released into the public domain.
module;
#include <filesystem>
#include <optional>
#include <ranges>
#include <string>
#include <paths.h>
export module nihil.posix:open_in_path;
import nihil.error;
import :fd;
import :getenv;
import :open;
namespace nihil {
// Find an executable in $PATH and open it with O_EXEC. If $PATH is not set, uses _PATH_DEFPATH.
// If the file can't be found or opened, returns std::nullopt.
export [[nodiscard]] auto open_in_path(std::filesystem::path const &file) -> std::optional<fd>
{
using namespace std::literals;
auto try_open = [](std::filesystem::path const &file) -> std::optional<fd> {
auto ret = open(file, open_exec);
if (ret)
return {std::move(*ret)};
return {};
};
// Absolute pathname skips the search.
if (file.is_absolute())
return try_open(file);
auto path = getenv("PATH").value_or(_PATH_DEFPATH); // NOLINT
for (auto &&dir : path | std::views::split(':')) {
// An empty $PATH element means cwd.
auto sdir = dir.empty() ? std::filesystem::path(".")
: std::filesystem::path(std::string_view(dir));
if (auto ret = try_open(sdir / file); ret)
return ret;
}
return {};
}
} // namespace nihil
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