LibCore: Add CDirIterator, and use it in everything rather than readdir

LibCore/CDirIterator.cpp

@@ -0,0 +1,68 @@
+#include "CDirIterator.h"
+#include <cerrno>
+
+CDirIterator::CDirIterator(const String& path, Flags flags)
+    : m_flags(flags)
+{
+    m_dir = opendir(path.characters());
+    if (m_dir == nullptr) {
+        m_error = errno;
+    }
+}
+
+CDirIterator::~CDirIterator()
+{
+    if (m_dir != nullptr) {
+        closedir(m_dir);
+        m_dir = nullptr;
+    }
+}
+
+bool CDirIterator::advance_next()
+{
+    if (m_dir == nullptr)
+        return false;
+
+    bool keep_advancing = true;
+    while (keep_advancing) {
+        errno = 0;
+        auto* de = readdir(m_dir);
+        if (de) {
+            m_next = de->d_name;
+        } else {
+            m_error = errno;
+            m_next = String();
+        }
+
+        if (m_next.is_null()) {
+            keep_advancing = false;
+        } else if (m_flags & Flags::SkipDots) {
+            if (m_next.length() < 1 || m_next[0] != '.') {
+                keep_advancing = false;
+            }
+        } else {
+            keep_advancing = false;
+        }
+    }
+
+    return m_next.length() > 0;
+}
+
+bool CDirIterator::has_next()
+{
+    if (!m_next.is_null())
+        return true;
+
+    return advance_next();
+}
+
+String CDirIterator::next_path()
+{
+    if (m_next.is_null())
+        advance_next();
+
+    auto tmp = m_next;
+    m_next = String();
+    return tmp;
+}
+