Examples with HasherOutputStream com.facebook.buck.util.hash.HasherOutputStream used on opensource projects

Example 1 with HasherOutputStream

use of com.facebook.buck.util.hash.HasherOutputStream in project buck by facebook.

the class HttpArtifactCacheBinaryProtocol method createMetadataHeader.

@VisibleForTesting
static byte[] createMetadataHeader(ImmutableSet<RuleKey> ruleKeys, ImmutableMap<String, String> metadata, ByteSource data) throws IOException {
    ByteArrayOutputStream rawOut = new ByteArrayOutputStream();
    Hasher hasher = HASH_FUNCTION.newHasher();
    try (DataOutputStream out = new DataOutputStream(new HasherOutputStream(hasher, rawOut))) {
        // Write the rule keys to the raw metadata, including them in the end-to-end checksum.
        out.writeInt(ruleKeys.size());
        for (RuleKey ruleKey : ruleKeys) {
            out.writeUTF(ruleKey.toString());
        }
        // Write out the metadata map to the raw metadata, including it in the end-to-end checksum.
        out.writeInt(metadata.size());
        for (Map.Entry<String, String> ent : metadata.entrySet()) {
            out.writeUTF(ent.getKey());
            byte[] val = ent.getValue().getBytes(Charsets.UTF_8);
            out.writeInt(val.length);
            out.write(val);
            if (out.size() > MAX_METADATA_HEADER_SIZE) {
                throw new IOException("Metadata header too big.");
            }
        }
    }
    // Add the file data contents to the end-to-end checksum.
    data.copyTo(new HasherOutputStream(hasher, ByteStreams.nullOutputStream()));
    // Finish the checksum, adding it to the raw metadata
    rawOut.write(hasher.hash().asBytes());
    // Finally, base64 encode the raw bytes to make usable in a HTTP header.
    byte[] bytes = rawOut.toByteArray();
    if (bytes.length > MAX_METADATA_HEADER_SIZE) {
        throw new IOException("Metadata header too big.");
    }
    return bytes;
}