src/com/android/managedprovisioning/model/PackageDownloadInfo.java

/*
 * Copyright 2016, 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.managedprovisioning.model;

import static com.android.internal.util.Preconditions.checkArgument;
import static com.android.internal.util.Preconditions.checkNotNull;

import android.os.Parcel;
import android.os.Parcelable;
import android.support.annotation.Nullable;
import android.text.TextUtils;

import java.util.Arrays;
import java.util.Objects;

import com.android.internal.annotations.Immutable;

/**
 * Stores the device admin package download information.
 */
@Immutable
public final class PackageDownloadInfo implements Parcelable {
    public static final byte[] DEFAULT_PACKAGE_CHECKSUM = new byte[0];
    public static final byte[] DEFAULT_SIGNATURE_CHECKSUM = new byte[0];
    public static final boolean DEFAULT_PACKAGE_CHECKSUM_SUPPORTS_SHA1 = false;
    // Always download packages if no minimum version given.
    public static final int DEFAULT_MINIMUM_VERSION = Integer.MAX_VALUE;

    public static final Parcelable.Creator<PackageDownloadInfo> CREATOR
            = new Parcelable.Creator<PackageDownloadInfo>() {
        @Override
        public PackageDownloadInfo createFromParcel(Parcel in) {
            return new PackageDownloadInfo(in);
        }

        @Override
        public PackageDownloadInfo[] newArray(int size) {
            return new PackageDownloadInfo[size];
        }
    };

    /**
     * Url where the package (.apk) can be downloaded from. {@code null} if there is no download
     * location specified.
     */
    public final String location;
    /** Cookie header for http request. */
    @Nullable
    public final String cookieHeader;
    /**
     * One of the following two checksums should be non empty. SHA-256 or SHA-1 hash of the
     * .apk file, or empty array if not used.
     */
    public final byte[] packageChecksum;
    /** SHA-256 hash of the signature in the .apk file, or empty array if not used. */
    public final byte[] signatureChecksum;
    /** Minimum supported version code of the downloaded package. */
    public final int minVersion;
    /**
     * If this is false, packageChecksum can only be SHA-256 hash, otherwise SHA-1 is also
     * supported.
     */
    public final boolean packageChecksumSupportsSha1;

    private PackageDownloadInfo(Builder builder) {
        location = builder.mLocation;
        cookieHeader = builder.mCookieHeader;
        packageChecksum = checkNotNull(builder.mPackageChecksum, "package checksum can't be null");
        signatureChecksum = checkNotNull(builder.mSignatureChecksum,
                "signature checksum can't be null");
        minVersion = builder.mMinVersion;
        packageChecksumSupportsSha1 = builder.mPackageChecksumSupportsSha1;

        validateFields();
    }

    private PackageDownloadInfo(Parcel in) {
        minVersion = in.readInt();
        location = in.readString();
        cookieHeader = in.readString();
        packageChecksum = checkNotNull(in.createByteArray());
        signatureChecksum = checkNotNull(in.createByteArray());
        packageChecksumSupportsSha1 = in.readInt() == 1;

        validateFields();
    }

    private void validateFields() {
        if (TextUtils.isEmpty(location)) {
            throw new IllegalArgumentException("Download location must not be empty.");
        }
        if (packageChecksum.length == 0 && signatureChecksum.length == 0) {
            throw new IllegalArgumentException("Package checksum or signature checksum must be "
                    + "provided.");
        }
    }

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel out, int flags) {
        out.writeInt(minVersion);
        out.writeString(location);
        out.writeString(cookieHeader);
        out.writeByteArray(packageChecksum);
        out.writeByteArray(signatureChecksum);
        out.writeInt(packageChecksumSupportsSha1 ? 1 : 0);
    }

    @Override
    public boolean equals(Object o) {
        if (this == o) {
            return true;
        }
        if (o == null || getClass() != o.getClass()) {
            return false;
        }
        PackageDownloadInfo that = (PackageDownloadInfo) o;
        return minVersion == that.minVersion
                && packageChecksumSupportsSha1 == that.packageChecksumSupportsSha1
                && Objects.equals(location, that.location)
                && Objects.equals(cookieHeader, that.cookieHeader)
                && Arrays.equals(packageChecksum, that.packageChecksum)
                && Arrays.equals(signatureChecksum, that.signatureChecksum);
    }

    public final static class Builder {
        private String mLocation;
        private String mCookieHeader;
        private byte[] mPackageChecksum = DEFAULT_PACKAGE_CHECKSUM;
        private byte[] mSignatureChecksum = DEFAULT_SIGNATURE_CHECKSUM;
        private int mMinVersion = DEFAULT_MINIMUM_VERSION;
        private boolean mPackageChecksumSupportsSha1 = DEFAULT_PACKAGE_CHECKSUM_SUPPORTS_SHA1;

        public Builder setLocation(String location) {
            mLocation = location;
            return this;
        }

        public Builder setCookieHeader(String cookieHeader) {
            mCookieHeader = cookieHeader;
            return this;
        }

        public Builder setPackageChecksum(byte[] packageChecksum) {
            mPackageChecksum = packageChecksum;
            return this;
        }

        public Builder setSignatureChecksum(byte[] signatureChecksum) {
            mSignatureChecksum = signatureChecksum;
            return this;
        }

        public Builder setMinVersion(int minVersion) {
            mMinVersion = minVersion;
            return this;
        }

        // TODO: remove once SHA-1 is fully deprecated.
        public Builder setPackageChecksumSupportsSha1(boolean packageChecksumSupportsSha1) {
            mPackageChecksumSupportsSha1 = packageChecksumSupportsSha1;
            return this;
        }

        public PackageDownloadInfo build() {
            return new PackageDownloadInfo(this);
        }

        public static Builder builder() {
            return new Builder();
        }
    }
}