tools/aapt2/link/TableMerger.h

/*
 * 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_TABLEMERGER_H
#define AAPT_TABLEMERGER_H

#include "Resource.h"
#include "ResourceTable.h"
#include "ResourceValues.h"
#include "filter/ConfigFilter.h"
#include "io/File.h"
#include "process/IResourceTableConsumer.h"
#include "util/Util.h"

#include <functional>
#include <map>

namespace aapt {

struct FileToMerge {
    /**
     * The compiled file from which to read the data.
     */
    io::IFile* file;

    /**
     * Where the original, uncompiled file came from.
     */
    Source originalSource;

    /**
     * The destination path within the APK/archive.
     */
    std::string dstPath;
};

struct TableMergerOptions {
    /**
     * If true, resources in overlays can be added without previously having existed.
     */
    bool autoAddOverlay = false;

    /**
     * A filter that removes resources whose configurations don't match.
     */
    IConfigFilter* filter = nullptr;
};

/**
 * TableMerger takes resource tables and merges all packages within the tables that have the same
 * package ID.
 *
 * If a package has a different name, all the entries in that table have their names mangled
 * to include the package name. This way there are no collisions. In order to do this correctly,
 * the TableMerger needs to also mangle any FileReference paths. Once these are mangled,
 * the original source path of the file, along with the new destination path is recorded in the
 * queue returned from getFileMergeQueue().
 *
 * Once the merging is complete, a separate process can go collect the files from the various
 * source APKs and either copy or process their XML and put them in the correct location in
 * the final APK.
 */
class TableMerger {
public:
    /**
     * Note: The outTable ResourceTable must live longer than this TableMerger. References
     * are made to this ResourceTable for efficiency reasons.
     */
    TableMerger(IAaptContext* context, ResourceTable* outTable, const TableMergerOptions& options);

    const std::map<ResourceKeyRef, FileToMerge>& getFilesToMerge() {
        return mFilesToMerge;
    }

    const std::set<std::u16string>& getMergedPackages() const {
        return mMergedPackages;
    }

    /**
     * Merges resources from the same or empty package. This is for local sources.
     */
    bool merge(const Source& src, ResourceTable* table);

    /**
     * Merges resources from an overlay ResourceTable.
     */
    bool mergeOverlay(const Source& src, ResourceTable* table);

    /**
     * Merges resources from the given package, mangling the name. This is for static libraries.
     * An io::IFileCollection is needed in order to find the referenced Files and process them.
     */
    bool mergeAndMangle(const Source& src, const StringPiece16& package, ResourceTable* table,
                        io::IFileCollection* collection);

    /**
     * Merges a compiled file that belongs to this same or empty package. This is for local sources.
     */
    bool mergeFile(const ResourceFile& fileDesc, io::IFile* file);

    /**
     * Merges a compiled file from an overlay, overriding an existing definition.
     */
    bool mergeFileOverlay(const ResourceFile& fileDesc, io::IFile* file);

private:
    using FileMergeCallback = std::function<bool(const ResourceNameRef&,
                                                 const ConfigDescription& config,
                                                 FileReference*,
                                                 FileReference*)>;

    IAaptContext* mContext;
    ResourceTable* mMasterTable;
    TableMergerOptions mOptions;
    ResourceTablePackage* mMasterPackage;

    std::set<std::u16string> mMergedPackages;
    std::map<ResourceKeyRef, FileToMerge> mFilesToMerge;

    bool mergeFileImpl(const ResourceFile& fileDesc, io::IFile* file, bool overlay);

    bool mergeImpl(const Source& src, ResourceTable* srcTable,
                   bool overlay, bool allowNew);

    bool doMerge(const Source& src, ResourceTable* srcTable, ResourceTablePackage* srcPackage,
                 const bool manglePackage,
                 const bool overlay,
                 const bool allowNewResources,
                 FileMergeCallback callback);

    std::unique_ptr<FileReference> cloneAndMangleFile(const std::u16string& package,
                                                      const FileReference& value);
};

} // namespace aapt

#endif /* AAPT_TABLEMERGER_H */