LibWeb: Add LayoutRange::normalized()

We use this to ensure that we're always working with a selection where
the start() is before the end() in document order. That simplifies all
the logic around this.

1 files changed, 46 insertions, 0 deletions

diff --git a/Libraries/LibWeb/Layout/LayoutPosition.cpp b/Libraries/LibWeb/Layout/LayoutPosition.cpp
new file mode 100644
index 0000000000..e171a34c15
--- /dev/null
+++ b/Libraries/LibWeb/Layout/LayoutPosition.cpp
@@ -0,0 +1,46 @@
+/*
+ * Copyright (c) 2020, Andreas Kling <kling@serenityos.org>
+ * 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/Layout/LayoutNode.h>
+#include <LibWeb/Layout/LayoutPosition.h>
+
+namespace Web {
+
+LayoutRange LayoutRange::normalized() const
+{
+    if (!is_valid())
+        return {};
+    if (m_start.layout_node == m_end.layout_node) {
+        if (m_start.index_in_node < m_end.index_in_node)
+            return *this;
+        return { m_end, m_start };
+    }
+    if (m_start.layout_node->is_before(*m_end.layout_node))
+        return *this;
+    return { m_end, m_start };
+}
+
+}