com.google.template.soy.msgs.SoyMsgIdConverter.java Source code

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Here is the source code for com.google.template.soy.msgs.SoyMsgIdConverter.java

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/*
 * Copyright 2018 Google Inc.
 *
 * 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.google.template.soy.msgs;

import com.google.common.collect.ImmutableList;
import com.google.common.io.BaseEncoding;
import com.google.common.primitives.Longs;

/**
 * Helper class to facilitate handling of message IDs created using the Soy <code>msgWithId</code>
 * function.
 *
 * <p>See go/soy-text-auditing for more details on Soy text auditing.
 */
public final class SoyMsgIdConverter {

    /**
     * Converts received message ID strings, as rendered by the Soy <code>msgId</code> function, into
     * a list of long message IDs.
     *
     * <p>The message IDs are generated by Soy as Base64 web safe ("base64url")-encoded int64s.
     *
     * <p>For example, "URTo5tnzILU=" = [0x51 0x14 0xe8 0xe6 0xd9 0xf3 0x20 0xb5] = 0x5114e8e6d9f320b5
     * = 5842550694803087541.
     *
     * @throws IllegalArgumentException if any of the strings fails to decode into message IDs, is too
     *     long or too short.
     */
    public static ImmutableList<Long> convertSoyMessageIdStrings(Iterable<String> encodedIds) {
        ImmutableList.Builder<Long> messageIds = ImmutableList.builder();
        for (String encodedId : encodedIds) {
            byte[] decodedBytes = BaseEncoding.base64Url().decode(encodedId);
            if (decodedBytes.length != Long.BYTES) {
                throw new IllegalArgumentException(
                        String.format("The message ID to decode ('%s') was of invalid size (%d != %d)", encodedId,
                                decodedBytes.length, Long.BYTES));
            }
            messageIds.add(Longs.fromByteArray(decodedBytes));
        }
        return messageIds.build();
    }

    private SoyMsgIdConverter() {
    } // Do not construct
}