refactor: create filesystem::current_path() and filesystem::absolute()

synfig-core/src/synfig/filesystem_path.cpp

@@ -40,6 +40,8 @@
 
 #include <glibmm/miscutils.h>
 
+#include <synfig/os.h>
+
 # ifdef _WIN32
 #  include <codecvt>
 #  include <locale>
@@ -778,6 +780,18 @@ filesystem::swap(Path& lhs, Path& rhs) noexcept
 	return lhs.swap(rhs);
 }
 
+filesystem::Path
+filesystem::current_path()
+{
+	return synfig::OS::get_current_working_directory();
+}
+
+filesystem::Path
+filesystem::absolute(const Path& p)
+{
+	return current_path() / p;
+}
+
 std::string
 filesystem::Path::basename(const std::string& str)
 {

synfig-core/src/synfig/filesystem_path.h

@@ -293,6 +293,28 @@ class Path {
 
 void swap(synfig::filesystem::Path& lhs, synfig::filesystem::Path& rhs) noexcept;
 
+/**
+ * Returns the current path, also known as current working directory.
+ *
+ * It just calls the synfig::OS::get_current_working_directory().
+ * It is defined here for convinience and to imitate the C++17 filesystem namespace.
+ *
+ * @return the current working directory
+ */
+Path current_path();
+
+/**
+ * The absolute path of relative (or absolute) path @a p.
+ *
+ * If @a p is an absolute path, returns itself.
+ * Otherwise, resolves the rlative path p based on the current working directory.
+ * @see synfig::filesystem::current_path()
+ *
+ * @param p the path to find its absolute path version
+ * @return current_path() / p
+ */
+Path absolute(const synfig::filesystem::Path& p);
+
 inline bool operator==(const Path& lhs, const Path& rhs) noexcept
 	{ return lhs.compare(rhs) == 0; }
 

synfig-core/src/synfig/os.cpp

@@ -46,6 +46,8 @@
 # define UNIX_PIPE_TO_PROCESSES
 # include <cstdlib> // for system()
 # include <fcntl.h> // for O_ flags
+# include <limits.h> // PATH_MAX
+# include <sys/stat.h> // for S_ISDIR() and stat()
 # include <sys/wait.h> // for waitpid()
 # include <unistd.h> // for popen()
 #elif defined(_WIN32)
@@ -778,3 +780,38 @@ OS::get_user_lang()
 #endif
 	return language_list;
 }
+
+filesystem::Path
+OS::get_current_working_directory()
+{
+#ifdef _WIN32
+	DWORD length = GetCurrentDirectoryW(0, nullptr);
+
+	std::vector<filesystem::Path::value_type> current_dir_str(length);
+	if (GetCurrentDirectoryW(length, current_dir_str.data()) != length - 1)
+		return filesystem::Path("/");
+
+	return filesystem::Path::from_native(current_dir_str.data()).lexically_normal();
+#else
+
+	struct stat st;
+	if (char* pwd = getenv("PWD")) {
+		if (stat(pwd, &st) == 0 && S_ISDIR(st.st_mode)) {
+			return filesystem::Path::from_native(pwd).lexically_normal();
+		}
+	}
+
+	std::vector<char> buffer(PATH_MAX);
+	char* ptr = nullptr;
+
+	while (!ptr) {
+		ptr = getcwd(buffer.data(), buffer.size());
+		if (!ptr) {
+			if (errno != ERANGE)
+				return filesystem::Path("/");
+			buffer.resize(buffer.size() * 2);
+		}
+	}
+	return filesystem::Path::from_native(buffer.data()).lexically_normal();
+#endif
+}

synfig-core/src/synfig/os.h

@@ -227,6 +227,17 @@ const std::vector<std::string>& get_user_lang();
  */
 filesystem::Path get_binary_path(const std::string& fallback_path);
 
+/**
+ * Returns the current working directory.
+ *
+ * The current working directory is that used as the starting point in pathname
+ * resolution. It is initially defined by OS and associated to the current process
+ * at its launch, but it can be changed at runtime.
+ *
+ * @return the current working directory
+ */
+filesystem::Path get_current_working_directory();
+
 } // END of namespace OS
 
 } // END of namespace synfig