Merge "Move chunk proto definitions into the BackupEncrypter APK"

 */

syntax = "proto2";

package com.android.server.backup.encryption.chunk;

package android_backup_crypto;

option java_package = "com.android.server.backup.encryption.protos";

option java_outer_classname = "ChunksMetadataProto";

// Cipher type with which the chunks are encrypted. For now we only support AES/GCM/NoPadding, but

/*

 * Copyright (C) 2018 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.

 */

package com.android.server.backup.encryption.chunk;

import android.util.proto.ProtoInputStream;

import java.io.IOException;

/**

 * Information about a chunk entry in a protobuf. Only used for reading from a {@link

 * ProtoInputStream}.

 */

public class Chunk {

    /**

     * Reads a Chunk from a {@link ProtoInputStream}. Expects the message to be of format {@link

     * ChunksMetadataProto.Chunk}.

     *

     * @param inputStream currently at a {@link ChunksMetadataProto.Chunk} message.

     * @throws IOException when the message is not structured as expected or a field can not be

     *     read.

     */

    static Chunk readFromProto(ProtoInputStream inputStream) throws IOException {

        Chunk result = new Chunk();

        while (inputStream.nextField() != ProtoInputStream.NO_MORE_FIELDS) {

            switch (inputStream.getFieldNumber()) {

                case (int) ChunksMetadataProto.Chunk.HASH:

                    result.mHash = inputStream.readBytes(ChunksMetadataProto.Chunk.HASH);

                    break;

                case (int) ChunksMetadataProto.Chunk.LENGTH:

                    result.mLength = inputStream.readInt(ChunksMetadataProto.Chunk.LENGTH);

                    break;

            }

        }

        return result;

    }

    private int mLength;

    private byte[] mHash;

    /** Private constructor. This class should only be instantiated by calling readFromProto. */

    private Chunk() {

        // Set default values for fields in case they are not available in the proto.

        mHash = new byte[]{};

        mLength = 0;

    }

    public int getLength() {

        return mLength;

    }

    public byte[] getHash() {

        return mHash;

    }

}

/*

 * Copyright (C) 2019 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.

 */

package com.android.server.backup.encryption.chunk;

import android.annotation.Nullable;

import android.util.proto.ProtoInputStream;

import java.io.IOException;

import java.util.Collections;

import java.util.HashMap;

import java.util.Map;

/**

 * Chunk listing in a format optimized for quick look-up of chunks via their hash keys. This is

 * useful when building an incremental backup. After a chunk has been produced, the algorithm can

 * quickly look up whether the chunk existed in the previous backup by checking this chunk listing.

 * It can then tell the server to use that chunk, through telling it the position and length of the

 * chunk in the previous backup's blob.

 */

public class ChunkListingMap {

    /**

     * Reads a ChunkListingMap from a {@link ProtoInputStream}. Expects the message to be of format

     * {@link ChunksMetadataProto.ChunkListing}.

     *

     * @param inputStream Currently at a {@link ChunksMetadataProto.ChunkListing} message.

     * @throws IOException when the message is not structured as expected or a field can not be

     *     read.

     */

    public static ChunkListingMap readFromProto(ProtoInputStream inputStream) throws IOException {

        Map<ChunkHash, Entry> entries = new HashMap();

        long start = 0;

        while (inputStream.nextField() != ProtoInputStream.NO_MORE_FIELDS) {

            if (inputStream.getFieldNumber() == (int) ChunksMetadataProto.ChunkListing.CHUNKS) {

                long chunkToken = inputStream.start(ChunksMetadataProto.ChunkListing.CHUNKS);

                Chunk chunk = Chunk.readFromProto(inputStream);

                entries.put(new ChunkHash(chunk.getHash()), new Entry(start, chunk.getLength()));

                start += chunk.getLength();

                inputStream.end(chunkToken);

            }

        }

        return new ChunkListingMap(entries);

    }

    private final Map<ChunkHash, Entry> mChunksByHash;

    private ChunkListingMap(Map<ChunkHash, Entry> chunksByHash) {

        mChunksByHash = Collections.unmodifiableMap(new HashMap<>(chunksByHash));

    }

    /** Returns {@code true} if there is a chunk with the given SHA-256 MAC key in the listing. */

    public boolean hasChunk(ChunkHash hash) {

        return mChunksByHash.containsKey(hash);

    }

    /**

     * Returns the entry for the chunk with the given hash.

     *

     * @param hash The SHA-256 MAC of the plaintext of the chunk.

     * @return The entry, containing position and length of the chunk in the backup blob, or null if

     *     it does not exist.

     */

    @Nullable

    public Entry getChunkEntry(ChunkHash hash) {

        return mChunksByHash.get(hash);

    }

    /** Returns the number of chunks in this listing. */

    public int getChunkCount() {

        return mChunksByHash.size();

    }

    /** Information about a chunk entry in a backup blob - i.e., its position and length. */

    public static final class Entry {

        private final int mLength;

        private final long mStart;

        private Entry(long start, int length) {

            mStart = start;

            mLength = length;

        }

        /** Returns the length of the chunk in bytes. */

        public int getLength() {

            return mLength;

        }

        /** Returns the start position of the chunk in the backup blob, in bytes. */

        public long getStart() {

            return mStart;

        }

    }

}

package com.android.server.backup.encryption.chunk;

import static com.android.server.backup.encryption.chunk.ChunksMetadataProto.CHUNK_ORDERING_TYPE_UNSPECIFIED;

import static com.android.server.backup.encryption.chunk.ChunksMetadataProto.EXPLICIT_STARTS;

import static com.android.server.backup.encryption.chunk.ChunksMetadataProto.INLINE_LENGTHS;

import static com.android.server.backup.encryption.protos.nano.ChunksMetadataProto.CHUNK_ORDERING_TYPE_UNSPECIFIED;

import static com.android.server.backup.encryption.protos.nano.ChunksMetadataProto.EXPLICIT_STARTS;

import static com.android.server.backup.encryption.protos.nano.ChunksMetadataProto.INLINE_LENGTHS;

import android.annotation.IntDef;

package com.android.server.backup.encryption.chunking;

import com.android.server.backup.encryption.chunk.ChunkOrderingType;

import com.android.server.backup.encryption.chunk.ChunksMetadataProto;

import com.android.server.backup.encryption.protos.nano.ChunksMetadataProto;

import java.io.IOException;