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diff --git a/tools/aapt2/Maybe.h b/tools/aapt2/Maybe.h
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+++ b/tools/aapt2/Maybe.h
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+/*
+ * Copyright (C) 2015 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef AAPT_MAYBE_H
+#define AAPT_MAYBE_H
+
+#include <cassert>
+#include <type_traits>
+#include <utility>
+
+namespace aapt {
+
+/**
+ * Either holds a valid value of type T, or holds Nothing.
+ * The value is stored inline in this structure, so no
+ * heap memory is used when creating a Maybe<T> object.
+ */
+template <typename T>
+class Maybe {
+public:
+    /**
+     * Construct Nothing.
+     */
+    Maybe();
+
+    ~Maybe();
+
+    Maybe(const Maybe& rhs);
+
+    template <typename U>
+    Maybe(const Maybe<U>& rhs);
+
+    Maybe(Maybe&& rhs);
+
+    template <typename U>
+    Maybe(Maybe<U>&& rhs);
+
+    Maybe& operator=(const Maybe& rhs);
+
+    template <typename U>
+    Maybe& operator=(const Maybe<U>& rhs);
+
+    Maybe& operator=(Maybe&& rhs);
+
+    template <typename U>
+    Maybe& operator=(Maybe<U>&& rhs);
+
+    /**
+     * Construct a Maybe holding a value.
+     */
+    Maybe(const T& value);
+
+    /**
+     * Construct a Maybe holding a value.
+     */
+    Maybe(T&& value);
+
+    /**
+     * True if this holds a value, false if
+     * it holds Nothing.
+     */
+    operator bool() const;
+
+    /**
+     * Gets the value if one exists, or else
+     * panics.
+     */
+    T& value();
+
+    /**
+     * Gets the value if one exists, or else
+     * panics.
+     */
+    const T& value() const;
+
+private:
+    template <typename U>
+    friend class Maybe;
+
+    template <typename U>
+    Maybe& copy(const Maybe<U>& rhs);
+
+    template <typename U>
+    Maybe& move(Maybe<U>&& rhs);
+
+    void destroy();
+
+    bool mNothing;
+
+    typename std::aligned_storage<sizeof(T), alignof(T)>::type mStorage;
+};
+
+template <typename T>
+Maybe<T>::Maybe()
+: mNothing(true) {
+}
+
+template <typename T>
+Maybe<T>::~Maybe() {
+    if (!mNothing) {
+        destroy();
+    }
+}
+
+template <typename T>
+Maybe<T>::Maybe(const Maybe& rhs)
+: mNothing(rhs.mNothing) {
+    if (!rhs.mNothing) {
+        new (&mStorage) T(reinterpret_cast<const T&>(rhs.mStorage));
+    }
+}
+
+template <typename T>
+template <typename U>
+Maybe<T>::Maybe(const Maybe<U>& rhs)
+: mNothing(rhs.mNothing) {
+    if (!rhs.mNothing) {
+        new (&mStorage) T(reinterpret_cast<const U&>(rhs.mStorage));
+    }
+}
+
+template <typename T>
+Maybe<T>::Maybe(Maybe&& rhs)
+: mNothing(rhs.mNothing) {
+    if (!rhs.mNothing) {
+        rhs.mNothing = true;
+
+        // Move the value from rhs.
+        new (&mStorage) T(std::move(reinterpret_cast<T&>(rhs.mStorage)));
+        rhs.destroy();
+    }
+}
+
+template <typename T>
+template <typename U>
+Maybe<T>::Maybe(Maybe<U>&& rhs)
+: mNothing(rhs.mNothing) {
+    if (!rhs.mNothing) {
+        rhs.mNothing = true;
+
+        // Move the value from rhs.
+        new (&mStorage) T(std::move(reinterpret_cast<U&>(rhs.mStorage)));
+        rhs.destroy();
+    }
+}
+
+template <typename T>
+inline Maybe<T>& Maybe<T>::operator=(const Maybe& rhs) {
+    // Delegate to the actual assignment.
+    return copy(rhs);
+}
+
+template <typename T>
+template <typename U>
+inline Maybe<T>& Maybe<T>::operator=(const Maybe<U>& rhs) {
+    return copy(rhs);
+}
+
+template <typename T>
+template <typename U>
+Maybe<T>& Maybe<T>::copy(const Maybe<U>& rhs) {
+    if (mNothing && rhs.mNothing) {
+        // Both are nothing, nothing to do.
+        return *this;
+    } else if  (!mNothing && !rhs.mNothing) {
+        // We both are something, so assign rhs to us.
+        reinterpret_cast<T&>(mStorage) = reinterpret_cast<const U&>(rhs.mStorage);
+    } else if (mNothing) {
+        // We are nothing but rhs is something.
+        mNothing = rhs.mNothing;
+
+        // Copy the value from rhs.
+        new (&mStorage) T(reinterpret_cast<const U&>(rhs.mStorage));
+    } else {
+        // We are something but rhs is nothing, so destroy our value.
+        mNothing = rhs.mNothing;
+        destroy();
+    }
+    return *this;
+}
+
+template <typename T>
+inline Maybe<T>& Maybe<T>::operator=(Maybe&& rhs) {
+    // Delegate to the actual assignment.
+    return move(std::forward<Maybe<T>>(rhs));
+}
+
+template <typename T>
+template <typename U>
+inline Maybe<T>& Maybe<T>::operator=(Maybe<U>&& rhs) {
+    return move(std::forward<Maybe<U>>(rhs));
+}
+
+template <typename T>
+template <typename U>
+Maybe<T>& Maybe<T>::move(Maybe<U>&& rhs) {
+    if (mNothing && rhs.mNothing) {
+        // Both are nothing, nothing to do.
+        return *this;
+    } else if  (!mNothing && !rhs.mNothing) {
+        // We both are something, so move assign rhs to us.
+        rhs.mNothing = true;
+        reinterpret_cast<T&>(mStorage) = std::move(reinterpret_cast<U&>(rhs.mStorage));
+        rhs.destroy();
+    } else if (mNothing) {
+        // We are nothing but rhs is something.
+        mNothing = false;
+        rhs.mNothing = true;
+
+        // Move the value from rhs.
+        new (&mStorage) T(std::move(reinterpret_cast<U&>(rhs.mStorage)));
+        rhs.destroy();
+    } else {
+        // We are something but rhs is nothing, so destroy our value.
+        mNothing = true;
+        destroy();
+    }
+    return *this;
+}
+
+template <typename T>
+Maybe<T>::Maybe(const T& value)
+: mNothing(false) {
+    new (&mStorage) T(value);
+}
+
+template <typename T>
+Maybe<T>::Maybe(T&& value)
+: mNothing(false) {
+    new (&mStorage) T(std::forward<T>(value));
+}
+
+template <typename T>
+Maybe<T>::operator bool() const {
+    return !mNothing;
+}
+
+template <typename T>
+T& Maybe<T>::value() {
+    assert(!mNothing && "Maybe<T>::value() called on Nothing");
+    return reinterpret_cast<T&>(mStorage);
+}
+
+template <typename T>
+const T& Maybe<T>::value() const {
+    assert(!mNothing && "Maybe<T>::value() called on Nothing");
+    return reinterpret_cast<const T&>(mStorage);
+}
+
+template <typename T>
+void Maybe<T>::destroy() {
+    reinterpret_cast<T&>(mStorage).~T();
+}
+
+template <typename T>
+inline Maybe<typename std::remove_reference<T>::type> make_value(T&& value) {
+    return Maybe<typename std::remove_reference<T>::type>(std::forward<T>(value));
+}
+
+template <typename T>
+inline Maybe<T> make_nothing() {
+    return Maybe<T>();
+}
+
+} // namespace aapt
+
+#endif // AAPT_MAYBE_H