Introduce TerminatedArray<T> type to make data-structure used by RuleSet visible at the type level.

Source/wtf/TerminatedArrayBuilder.h

+// Copyright 2014 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+#ifndef TerminatedArrayBuilder_h
+#define TerminatedArrayBuilder_h
+
+#include "wtf/OwnPtr.h"
+
+namespace WTF {
+
+template<typename T>
+class TerminatedArrayBuilder {
+    DISALLOW_ALLOCATION();
+    WTF_MAKE_NONCOPYABLE(TerminatedArrayBuilder);
+public:
+    explicit TerminatedArrayBuilder(PassOwnPtr<TerminatedArray<T> > array)
+        : m_array(array)
+        , m_count(0)
+        , m_capacity(0)
+    {
+        if (!m_array)
+            return;
+        m_capacity = m_count = m_array->size();
+    }
+
+    void grow(size_t count)
+    {
+        ASSERT(count);
+        if (!m_array) {
+            ASSERT(!m_count);
+            ASSERT(!m_capacity);
+            m_capacity = count;
+            m_array = TerminatedArray<T>::create(m_capacity);
+            return;
+        }
+        m_capacity += count;
+        m_array = TerminatedArray<T>::resize(m_array.release(), m_capacity);
+        m_array->at(m_count - 1).setLastInArray(false);
+    }
+
+    void append(const T& item)
+    {
+        RELEASE_ASSERT(m_count < m_capacity);
+        ASSERT(!item.isLastInArray());
+        m_array->at(m_count++) = item;
+    }
+
+    PassOwnPtr<TerminatedArray<T> > release()
+    {
+        RELEASE_ASSERT(m_count == m_capacity);
+        if (m_array)
+            m_array->at(m_count - 1).setLastInArray(true);
+        assertValid();
+        return m_array.release();
+    }
+
+private:
+#ifndef NDEBUG
+    void assertValid()
+    {
+        for (size_t i = 0; i < m_count; ++i) {
+            bool isLastInArray = (i + 1 == m_count);
+            ASSERT(m_array->at(i).isLastInArray() == isLastInArray);
+        }
+    }
+#else
+    void assertValid() { }
+#endif
+
+    OwnPtr<TerminatedArray<T> > m_array;
+    size_t m_count;
+    size_t m_capacity;
+};
+
+} // namespace WTF
+
+using WTF::TerminatedArrayBuilder;
+
+#endif // TerminatedArrayBuilder_h