AAPT2

First checking of AAPT2. The individual phases of AAPT2 work, but there
are some missing pieces.

For early testing we are missing:
- Need to properly mark file references and include them in package
- Need to package into zip

Final AAPT for apps we are missing:
- Need to crush PNGs
- Need to parse 9-patches
- Need to validate all of AndroidManifest.xml
- Need to write align method to align resource tables for splits.

Final AAPT for apps + system we are missing:
- Need to handle overlays
- Need to store comments for R file
- Need to handle --shared-lib (dynamic references too).

New AAPT features coming:
- Need to import compiled libraries
    - Name mangling
    - R file generation for library code

Change-Id: I95f8a63581b81a1f424ae6fb2c373c883b72c18d
diff --git a/tools/aapt2/ResourceValues.h b/tools/aapt2/ResourceValues.h
new file mode 100644
index 0000000..f25bcf0
--- /dev/null
+++ b/tools/aapt2/ResourceValues.h
@@ -0,0 +1,456 @@
+/*
+ * 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_RESOURCE_VALUES_H
+#define AAPT_RESOURCE_VALUES_H
+
+#include "Resource.h"
+#include "StringPool.h"
+
+#include <array>
+#include <androidfw/ResourceTypes.h>
+#include <ostream>
+#include <vector>
+
+namespace aapt {
+
+struct ValueVisitor;
+struct ConstValueVisitor;
+struct ValueVisitorArgs;
+
+/**
+ * A resource value. This is an all-encompassing representation
+ * of Item and Map and their subclasses. The way to do
+ * type specific operations is to check the Value's type() and
+ * cast it to the appropriate subclass. This isn't super clean,
+ * but it is the simplest strategy.
+ */
+struct Value {
+    /**
+     * Whether or not this is an Item.
+     */
+    virtual bool isItem() const;
+
+    /**
+     * Whether this value is weak and can be overriden without
+     * warning or error. Default for base class is false.
+     */
+    virtual bool isWeak() const;
+
+    /**
+     * Calls the appropriate overload of ValueVisitor.
+     */
+    virtual void accept(ValueVisitor& visitor, ValueVisitorArgs&& args) = 0;
+
+    /**
+     * Const version of accept().
+     */
+    virtual void accept(ConstValueVisitor& visitor, ValueVisitorArgs&& args) const = 0;
+
+    /**
+     * Clone the value.
+     */
+    virtual Value* clone() const = 0;
+
+    /**
+     * Human readable printout of this value.
+     */
+    virtual void print(std::ostream& out) const = 0;
+};
+
+/**
+ * Inherit from this to get visitor accepting implementations for free.
+ */
+template <typename Derived>
+struct BaseValue : public Value {
+    virtual void accept(ValueVisitor& visitor, ValueVisitorArgs&& args) override;
+    virtual void accept(ConstValueVisitor& visitor, ValueVisitorArgs&& args) const override;
+};
+
+/**
+ * A resource item with a single value. This maps to android::ResTable_entry.
+ */
+struct Item : public Value {
+    /**
+     * An Item is, of course, an Item.
+     */
+    virtual bool isItem() const override;
+
+    /**
+     * Clone the Item.
+     */
+    virtual Item* clone() const override = 0;
+
+    /**
+     * Fills in an android::Res_value structure with this Item's binary representation.
+     * Returns false if an error ocurred.
+     */
+    virtual bool flatten(android::Res_value& outValue) const = 0;
+};
+
+/**
+ * Inherit from this to get visitor accepting implementations for free.
+ */
+template <typename Derived>
+struct BaseItem : public Item {
+    virtual void accept(ValueVisitor& visitor, ValueVisitorArgs&& args) override;
+    virtual void accept(ConstValueVisitor& visitor, ValueVisitorArgs&& args) const override;
+};
+
+/**
+ * A reference to another resource. This maps to android::Res_value::TYPE_REFERENCE.
+ *
+ * A reference can be symbolic (with the name set to a valid resource name) or be
+ * numeric (the id is set to a valid resource ID).
+ */
+struct Reference : public BaseItem<Reference> {
+    enum class Type {
+        kResource,
+        kAttribute,
+    };
+
+    ResourceName name;
+    ResourceId id;
+    Reference::Type referenceType;
+    bool privateReference = false;
+
+    Reference();
+    Reference(const ResourceNameRef& n, Type type = Type::kResource);
+    Reference(const ResourceId& i, Type type = Type::kResource);
+
+    bool flatten(android::Res_value& outValue) const override;
+    Reference* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+/**
+ * An ID resource. Has no real value, just a place holder.
+ */
+struct Id : public BaseItem<Id> {
+    bool isWeak() const override;
+    bool flatten(android::Res_value& out) const override;
+    Id* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+/**
+ * A raw, unprocessed string. This may contain quotations,
+ * escape sequences, and whitespace. This shall *NOT*
+ * end up in the final resource table.
+ */
+struct RawString : public BaseItem<RawString> {
+    StringPool::Ref value;
+
+    RawString(const StringPool::Ref& ref);
+
+    bool flatten(android::Res_value& outValue) const override;
+    RawString* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+struct String : public BaseItem<String> {
+    StringPool::Ref value;
+
+    String(const StringPool::Ref& ref);
+
+    bool flatten(android::Res_value& outValue) const override;
+    String* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+struct StyledString : public BaseItem<StyledString> {
+    StringPool::StyleRef value;
+
+    StyledString(const StringPool::StyleRef& ref);
+
+    bool flatten(android::Res_value& outValue) const override;
+    StyledString* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+struct FileReference : public BaseItem<FileReference> {
+    StringPool::Ref path;
+
+    FileReference() = default;
+    FileReference(const StringPool::Ref& path);
+
+    bool flatten(android::Res_value& outValue) const override;
+    FileReference* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+/**
+ * Represents any other android::Res_value.
+ */
+struct BinaryPrimitive : public BaseItem<BinaryPrimitive> {
+    android::Res_value value;
+
+    BinaryPrimitive() = default;
+    BinaryPrimitive(const android::Res_value& val);
+
+    bool flatten(android::Res_value& outValue) const override;
+    BinaryPrimitive* clone() const override;
+    void print(::std::ostream& out) const override;
+};
+
+/**
+ * Sentinel value that should be ignored in the final output.
+ * Mainly used as a placeholder for public entries with no
+ * values defined yet.
+ */
+struct Sentinel : public BaseItem<Sentinel> {
+    bool isWeak() const override;
+    bool flatten(android::Res_value& outValue) const override;
+    Sentinel* clone() const override;
+    void print(::std::ostream& out) const override;
+};
+
+struct Attribute : public BaseValue<Attribute> {
+    struct Symbol {
+        Reference symbol;
+        uint32_t value;
+    };
+
+    bool weak;
+    uint32_t typeMask;
+    uint32_t minInt;
+    uint32_t maxInt;
+    std::vector<Symbol> symbols;
+
+    Attribute(bool w, uint32_t t = 0u);
+
+    bool isWeak() const override;
+    virtual Attribute* clone() const override;
+    virtual void print(std::ostream& out) const override;
+};
+
+struct Style : public BaseValue<Style> {
+    struct Entry {
+        Reference key;
+        std::unique_ptr<Item> value;
+    };
+
+    Reference parent;
+    std::vector<Entry> entries;
+
+    Style* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+struct Array : public BaseValue<Array> {
+    std::vector<std::unique_ptr<Item>> items;
+
+    Array* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+struct Plural : public BaseValue<Plural> {
+    enum {
+        Zero = 0,
+        One,
+        Two,
+        Few,
+        Many,
+        Other,
+        Count
+    };
+
+    std::array<std::unique_ptr<Item>, Count> values;
+
+    Plural* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+struct Styleable : public BaseValue<Styleable> {
+    std::vector<Reference> entries;
+
+    Styleable* clone() const override;
+    void print(std::ostream& out) const override;
+};
+
+/**
+ * Stream operator for printing Value objects.
+ */
+inline ::std::ostream& operator<<(::std::ostream& out, const Value& value) {
+    value.print(out);
+    return out;
+}
+
+/**
+ * The argument object that gets passed through the value
+ * back to the ValueVisitor. Subclasses of ValueVisitor should
+ * subclass ValueVisitorArgs to contain the data they need
+ * to operate.
+ */
+struct ValueVisitorArgs {};
+
+/**
+ * Visits a value and runs the appropriate method based on its type.
+ */
+struct ValueVisitor {
+    virtual void visit(Reference& reference, ValueVisitorArgs& args) {
+        visitItem(reference, args);
+    }
+
+    virtual void visit(RawString& string, ValueVisitorArgs& args) {
+        visitItem(string, args);
+    }
+
+    virtual void visit(String& string, ValueVisitorArgs& args) {
+        visitItem(string, args);
+    }
+
+    virtual void visit(StyledString& string, ValueVisitorArgs& args) {
+        visitItem(string, args);
+    }
+
+    virtual void visit(FileReference& file, ValueVisitorArgs& args) {
+        visitItem(file, args);
+    }
+
+    virtual void visit(Id& id, ValueVisitorArgs& args) {
+        visitItem(id, args);
+    }
+
+    virtual void visit(BinaryPrimitive& primitive, ValueVisitorArgs& args) {
+        visitItem(primitive, args);
+    }
+
+    virtual void visit(Sentinel& sentinel, ValueVisitorArgs& args) {
+        visitItem(sentinel, args);
+    }
+
+    virtual void visit(Attribute& attr, ValueVisitorArgs& args) {}
+    virtual void visit(Style& style, ValueVisitorArgs& args) {}
+    virtual void visit(Array& array, ValueVisitorArgs& args) {}
+    virtual void visit(Plural& array, ValueVisitorArgs& args) {}
+    virtual void visit(Styleable& styleable, ValueVisitorArgs& args) {}
+
+    virtual void visitItem(Item& item, ValueVisitorArgs& args) {}
+};
+
+/**
+ * Const version of ValueVisitor.
+ */
+struct ConstValueVisitor {
+    virtual void visit(const Reference& reference, ValueVisitorArgs& args) {
+        visitItem(reference, args);
+    }
+
+    virtual void visit(const RawString& string, ValueVisitorArgs& args) {
+        visitItem(string, args);
+    }
+
+    virtual void visit(const String& string, ValueVisitorArgs& args) {
+        visitItem(string, args);
+    }
+
+    virtual void visit(const StyledString& string, ValueVisitorArgs& args) {
+        visitItem(string, args);
+    }
+
+    virtual void visit(const FileReference& file, ValueVisitorArgs& args) {
+        visitItem(file, args);
+    }
+
+    virtual void visit(const Id& id, ValueVisitorArgs& args) {
+        visitItem(id, args);
+    }
+
+    virtual void visit(const BinaryPrimitive& primitive, ValueVisitorArgs& args) {
+        visitItem(primitive, args);
+    }
+
+    virtual void visit(const Sentinel& sentinel, ValueVisitorArgs& args) {
+        visitItem(sentinel, args);
+    }
+
+    virtual void visit(const Attribute& attr, ValueVisitorArgs& args) {}
+    virtual void visit(const Style& style, ValueVisitorArgs& args) {}
+    virtual void visit(const Array& array, ValueVisitorArgs& args) {}
+    virtual void visit(const Plural& array, ValueVisitorArgs& args) {}
+    virtual void visit(const Styleable& styleable, ValueVisitorArgs& args) {}
+
+    virtual void visitItem(const Item& item, ValueVisitorArgs& args) {}
+};
+
+/**
+ * Convenience Visitor that forwards a specific type to a function.
+ * Args are not used as the function can bind variables. Do not use
+ * directly, use the wrapper visitFunc() method.
+ */
+template <typename T, typename TFunc>
+struct ValueVisitorFunc : ValueVisitor {
+    TFunc func;
+
+    ValueVisitorFunc(TFunc f) : func(f) {
+    }
+
+    void visit(T& value, ValueVisitorArgs&) override {
+        func(value);
+    }
+};
+
+/**
+ * Const version of ValueVisitorFunc.
+ */
+template <typename T, typename TFunc>
+struct ConstValueVisitorFunc : ConstValueVisitor {
+    TFunc func;
+
+    ConstValueVisitorFunc(TFunc f) : func(f) {
+    }
+
+    void visit(const T& value, ValueVisitorArgs&) override {
+        func(value);
+    }
+};
+
+template <typename T, typename TFunc>
+void visitFunc(Value& value, TFunc f) {
+    ValueVisitorFunc<T, TFunc> visitor(f);
+    value.accept(visitor, ValueVisitorArgs{});
+}
+
+template <typename T, typename TFunc>
+void visitFunc(const Value& value, TFunc f) {
+    ConstValueVisitorFunc<T, TFunc> visitor(f);
+    value.accept(visitor, ValueVisitorArgs{});
+}
+
+template <typename Derived>
+void BaseValue<Derived>::accept(ValueVisitor& visitor, ValueVisitorArgs&& args) {
+    visitor.visit(static_cast<Derived&>(*this), args);
+}
+
+template <typename Derived>
+void BaseValue<Derived>::accept(ConstValueVisitor& visitor, ValueVisitorArgs&& args) const {
+    visitor.visit(static_cast<const Derived&>(*this), args);
+}
+
+template <typename Derived>
+void BaseItem<Derived>::accept(ValueVisitor& visitor, ValueVisitorArgs&& args) {
+    visitor.visit(static_cast<Derived&>(*this), args);
+}
+
+template <typename Derived>
+void BaseItem<Derived>::accept(ConstValueVisitor& visitor, ValueVisitorArgs&& args) const {
+    visitor.visit(static_cast<const Derived&>(*this), args);
+}
+
+} // namespace aapt
+
+#endif // AAPT_RESOURCE_VALUES_H