libluna: Make String::from_string_view handle non-null-terminated strings properly

libluna/include/luna/String.h

@@ -9,35 +9,53 @@ class String
     typedef const char* ConstIterator;
 
   public:
+    /* Constructs a String, which will take ownership of the given c-string. To create a String that makes its own
+     * internal copy of the passed string, use String::from_cstring(). */
     String(char* c_str);
+
+    /* Constructs a String with precalculated length, which will take ownership of the given c-string. To create a
+     * String that makes its own internal copy of the passed string, use String::from_cstring(). */
     String(char* c_str, usize length);
 
+    /* Constructs an empty String. */
     String();
 
     String(String&&);
+
+    /* Implicit copying is disabled for Strings, as copy constructors cannot use value-based error handling. To copy a
+     * string, please use the clone() method. */
     String(const String&) = delete;
 
     String& operator=(String&&);
+
+    /* Implicit copying is disabled for Strings, as copy constructors cannot use value-based error handling. To copy a
+     * string, please use the clone() method. */
     String& operator=(const String&) = delete;
 
     ~String();
 
+    /* Creates a copy of this String and returns it. */
     Result<String> clone() const;
 
+    /* Creates a copy of a specific segment of this String and returns it. */
     Result<String> substring(usize begin, usize size) const;
 
+    /* Splits a String with a delimiter. */
     Result<Vector<String>> split(StringView delim) const
     {
         return view().split(delim);
     }
 
+    /* Splits a String into two parts with a delimiter. */
     Result<Vector<String>> split_once(char delim) const
     {
         return view().split_once(delim);
     }
 
+    /* Creates a single String consisting of a list of strings separated by a delimiter. */
     static Result<String> join(const Vector<String>& vec, StringView delim);
 
+    /* Removes all trailing characters contained in delim. */
     void trim(StringView delim);
 
     static Result<String> format(const String& fmt, ...);
@@ -45,10 +63,7 @@ class String
     static Result<String> vformat(StringView fmt, va_list ap);
 
     static Result<String> from_cstring(const char* str);
-    static Result<String> from_string_view(StringView str)
-    {
-        return from_cstring(str.chars());
-    }
+    static Result<String> from_string_view(StringView str);
 
     const char* chars() const
     {

libluna/src/String.cpp

@@ -145,19 +145,23 @@ Result<String> String::vformat(StringView fmt, va_list ap)
 
 Result<String> String::from_cstring(const char* str)
 {
-    usize len = strlen(str);
-    if (len < sizeof(m_inline_storage))
+    return from_string_view(StringView { str });
+}
+
+Result<String> String::from_string_view(StringView str)
+{
+    if (str.length() < sizeof(m_inline_storage))
     {
         String result;
         result.m_inline = true;
-        result.m_length = len;
-        strncpy(result.m_inline_storage, str, sizeof(m_inline_storage));
+        result.m_length = str.length();
+        strncpy(result.m_inline_storage, str.chars(), sizeof(m_inline_storage));
         return result;
     }
 
-    char* const dup = strdup(str);
+    char* const dup = strndup(str.chars(), str.length());
     if (!dup) return err(ENOMEM);
-    return String { dup };
+    return String { dup, str.length() };
 }
 
 Result<String> String::join(const Vector<String>& vec, StringView delim)