diff -r 000000000000 -r 4f2f89ce4247 WebCore/html/HTMLInputStream.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/WebCore/html/HTMLInputStream.h	Fri Sep 17 09:02:29 2010 +0300
@@ -0,0 +1,136 @@
+/*
+ * Copyright (C) 2010 Google, Inc. 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 APPLE INC. ``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 APPLE INC. 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.
+ */
+
+#ifndef HTMLInputStream_h
+#define HTMLInputStream_h
+
+#include "SegmentedString.h"
+
+namespace WebCore {
+
+// The InputStream is made up of a sequence of SegmentedStrings:
+//
+// [--current--][--next--][--next--] ... [--next--]
+//            /\                         (also called m_last)
+//            L_ current insertion point
+//
+// The current segmented string is stored in InputStream.  Each of the
+// afterInsertionPoint buffers are stored in InsertionPointRecords on the
+// stack.
+//
+// We remove characters from the "current" string in the InputStream.
+// document.write() will add characters at the current insertion point,
+// which appends them to the "current" string.
+//
+// m_last is a pointer to the last of the afterInsertionPoint strings.
+// The network adds data at the end of the InputStream, which appends
+// them to the "last" string.
+class HTMLInputStream : public Noncopyable {
+public:
+    HTMLInputStream()
+        : m_last(&m_first)
+    {
+    }
+
+    void appendToEnd(const SegmentedString& string)
+    {
+        m_last->append(string);
+    }
+
+    void insertAtCurrentInsertionPoint(const SegmentedString& string)
+    {
+        m_first.append(string);
+    }
+
+    void markEndOfFile()
+    {
+        // FIXME: This should use InputStreamPreprocessor::endOfFileMarker
+        // once InputStreamPreprocessor is split off into its own header.
+        static const UChar endOfFileMarker = 0;
+        m_last->append(SegmentedString(String(&endOfFileMarker, 1)));
+        m_last->close();
+    }
+
+    bool haveSeenEndOfFile()
+    {
+        return m_last->isClosed();
+    }
+
+    SegmentedString& current() { return m_first; }
+
+    void splitInto(SegmentedString& next)
+    {
+        next = m_first;
+        m_first = SegmentedString();
+        if (m_last == &m_first) {
+            // We used to only have one SegmentedString in the InputStream
+            // but now we have two.  That means m_first is no longer also
+            // the m_last string, |next| is now the last one.
+            m_last = &next;
+        }
+    }
+
+    void mergeFrom(SegmentedString& next)
+    {
+        m_first.append(next);
+        if (m_last == &next) {
+            // The string |next| used to be the last SegmentedString in
+            // the InputStream.  Now that it's been merged into m_first,
+            // that makes m_first the last one.
+            m_last = &m_first;
+        }
+        if (next.isClosed()) {
+            // We also need to merge the "closed" state from next to
+            // m_first.  Arguably, this work could be done in append().
+            m_first.close();
+        }
+    }
+
+private:
+    SegmentedString m_first;
+    SegmentedString* m_last;
+};
+
+class InsertionPointRecord : public Noncopyable {
+public:
+    explicit InsertionPointRecord(HTMLInputStream& inputStream)
+        : m_inputStream(&inputStream)
+    {
+        m_inputStream->splitInto(m_next);
+    }
+
+    ~InsertionPointRecord()
+    {
+        m_inputStream->mergeFrom(m_next);
+    }
+
+private:
+    HTMLInputStream* m_inputStream;
+    SegmentedString m_next;
+};
+
+}
+
+#endif