1 files changed, 143 insertions, 0 deletions
diff --git a/web/xhtml/fragment.cxx b/web/xhtml/fragment.cxx
new file mode 100644
index 0000000..843db82
--- /dev/null
+++ b/web/xhtml/fragment.cxx
@@ -0,0 +1,143 @@
+// file      : web/xhtml/fragment.cxx -*- C++ -*-
+// license   : MIT; see accompanying LICENSE file
+
+#include <web/xhtml/fragment.hxx>
+
+#include <string>
+#include <cassert>
+
+#include <libstudxml/parser.hxx>
+#include <libstudxml/serializer.hxx>
+
+#include <web/xhtml/serialization.hxx>
+
+using namespace std;
+using namespace xml;
+
+namespace web
+{
+  namespace xhtml
+  {
+    fragment::
+    fragment (const string& text, const string& name, size_t length)
+    {
+      // To parse the fragment make it a valid xml document, wrapping with the
+      // root element. If requested, truncate the fragment before the
+      // first-level element when the content length limit is exceeded.
+      //
+      string doc ("<d>" + text + "</d>");
+
+      parser p (doc.c_str (),
+                doc.size (),
+                name,
+                parser::receive_elements   |
+                parser::receive_characters |
+                parser::receive_attributes_event);
+
+      size_t len (0);
+      size_t level (0);
+
+      for (parser::event_type e: p)
+      {
+        switch (e)
+        {
+        case parser::start_element:
+          {
+            truncated = length != 0 && level == 1 && len >= length;
+
+            if (truncated)
+              break;
+
+            ++level;
+          }
+          // Fall through.
+        case parser::start_attribute:
+          {
+            const auto& n (p.qname ());
+
+            if (!n.namespace_ ().empty ())
+              throw parsing (
+                name, p.line (), p.column (), "namespace is not allowed");
+
+            events_.emplace_back (e, n.name ());
+            break;
+          }
+        case parser::end_element:
+          {
+            --level;
+          }
+          // Fall through.
+        case parser::end_attribute:
+          {
+            events_.emplace_back (e, "");
+            break;
+          }
+        case parser::characters:
+          {
+            string& s (p.value ());
+
+            assert (!events_.empty ()); // Contains root element start.
+
+            if (events_.back ().first != parser::start_attribute)
+              len += s.size ();
+
+            events_.emplace_back (e, move (s));
+            break;
+          }
+        default:
+          assert (false);
+        }
+
+        if (truncated)
+        {
+          events_.emplace_back (parser::end_element, ""); // Close root.
+          break;
+        }
+      }
+
+      // Unwrap the fragment removing the root element events.
+      //
+      assert (events_.size () >= 2);
+      events_.erase (events_.begin ());
+      events_.pop_back ();
+    }
+
+    void fragment::
+    operator() (serializer& s) const
+    {
+      for (const auto& e: events_)
+      {
+        switch (e.first)
+        {
+        case parser::start_element:
+          {
+            s.start_element (xmlns, e.second);
+            break;
+          }
+        case parser::start_attribute:
+          {
+            s.start_attribute (e.second);
+            break;
+          }
+        case parser::end_element:
+          {
+            s.end_element ();
+            break;
+          }
+        case parser::end_attribute:
+          {
+            s.end_attribute ();
+            break;
+          }
+        case parser::characters:
+          {
+            s.characters (e.second);
+            break;
+          }
+        default:
+          assert (false);
+        }
+      }
+    }
+  }
+}