LibWeb: Make DOM::Range more suitable for JS.

Libraries/LibWeb/DOM/Range.cpp

@@ -0,0 +1,74 @@
+/*
+ * Copyright (c) 2020, the SerenityOS developers.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ *
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+ * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+ * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+ * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include <LibWeb/DOM/Document.h>
+#include <LibWeb/DOM/Node.h>
+#include <LibWeb/DOM/Range.h>
+
+namespace Web::DOM {
+
+Range::Range(Document& document)
+    : m_start_container(document)
+    , m_start_offset(0)
+    , m_end_container(document)
+    , m_end_offset(0)
+{
+}
+
+Range::Range(Node& start_container, size_t start_offset, Node& end_container, size_t end_offset)
+    : m_start_container(start_container)
+    , m_start_offset(start_offset)
+    , m_end_container(end_container)
+    , m_end_offset(end_offset)
+{
+}
+
+NonnullRefPtr<Range> Range::clone_range() const
+{
+    return adopt(*new Range(const_cast<Node&>(*m_start_container), m_start_offset, const_cast<Node&>(*m_end_container), m_end_offset));
+}
+
+NonnullRefPtr<Range> Range::inverted() const
+{
+    return adopt(*new Range(const_cast<Node&>(*m_end_container), m_end_offset, const_cast<Node&>(*m_start_container), m_start_offset));
+}
+
+NonnullRefPtr<Range> Range::normalized() const
+{
+    if (m_start_container.ptr() == m_end_container.ptr()) {
+        if (m_start_offset <= m_end_offset)
+            return clone_range();
+
+        return inverted();
+    }
+
+    if (m_start_container->is_before(m_end_container))
+        return clone_range();
+
+    return inverted();
+}
+
+}