libluna: Add PathParser, a C++-style way of iterating over path sections

Still uses strtok under the hood, though.

libluna/CMakeLists.txt

@@ -17,6 +17,7 @@ set(FREESTANDING_SOURCES
     src/DebugLog.cpp
     src/Heap.cpp
     src/Spinlock.cpp
+    src/PathParser.cpp
     src/UBSAN.cpp
 )
 

libluna/include/luna/PathParser.h

@@ -0,0 +1,28 @@
+#pragma once
+#include <luna/CString.h>
+#include <luna/Heap.h>
+
+class PathParser
+{
+  public:
+    static Result<PathParser> create(const char* path);
+
+    PathParser(PathParser&& other);
+    PathParser(const PathParser&) = delete;
+
+    ~PathParser();
+
+    bool is_absolute() const
+    {
+        return *m_original == '/';
+    }
+
+    Option<const char*> next();
+
+  private:
+    PathParser(const char* original, char* copy);
+
+    const char* m_original { nullptr };
+    char* m_copy { nullptr };
+    bool m_already_called_next { false };
+};

libluna/src/PathParser.cpp

@@ -0,0 +1,33 @@
+#include <luna/PathParser.h>
+
+Result<PathParser> PathParser::create(const char* path)
+{
+    char* copy = strdup(path);
+    if (!copy) return err(ENOMEM);
+
+    return PathParser { path, copy };
+}
+
+PathParser::PathParser(const char* original, char* copy) : m_original(original), m_copy(copy)
+{
+}
+
+PathParser::PathParser(PathParser&& other) : m_original(other.m_original), m_copy(other.m_copy)
+{
+    other.m_copy = nullptr;
+}
+
+PathParser::~PathParser()
+{
+    if (m_copy) free_impl(m_copy);
+}
+
+Option<const char*> PathParser::next()
+{
+    char* result = strtok(m_already_called_next ? nullptr : m_copy, "/");
+    m_already_called_next = true;
+
+    if (!result) return {};
+
+    return result;
+}