proto/transform.proto

// Copyright 2022 Google LLC
//
// 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.
syntax = "proto2";

package mobstore.proto;

option java_package = "com.google.mobiledatadownload";
option java_outer_classname = "TransformProto";
option objc_class_prefix = "MOB";

// Description of transforms that are to be applied by MobStore to a stream.
//
// Following MobStore convention, they are applied in the order in which they
// appear on write, and reverse on read. Serialization as a URI fragment
// preserves order.
//
// eg "transform=compress+encrypt(aes_gcm_key=12345)"
message Transforms {
  repeated Transform transform = 1;
}

// Specification for an individual transform.
message Transform {
  oneof transform {
    CompressTransform compress = 1;
    EncryptTransform encrypt = 2;
    IntegrityTransform integrity = 3;
    ZipTransform zip = 4;
    CustomTransform custom = 5;
  }
}

// The compression transform. It has no parameters.
//
// eg "compress"
message CompressTransform {}

// The encryption transform. If no params are given, it uses the keystore
// to manage keys. Alternatively, the key can be stored in the URI itself.
//
// eg "encrypt", "encrypt(aes_gcm_key=12345)"
message EncryptTransform {
  oneof key {
    string aes_gcm_key_base64 = 1;
  }
}

// The integrity transform. If the hash is included, it can be verified.
// Otherwise, it can be retrieved after reading or writing with the
// ComputedUri API.
//
// eg "integrity", "integrity(sha256=12345)"
message IntegrityTransform {
  oneof hash {
    string sha256 = 1;
  }
}

// The ZIP decompress transform. It requires a target file param.
message ZipTransform {
  // required
  optional string target = 1;
}

// A custom transform. The transform with the specified name must be registered
// with MobStore FileStorage.
message CustomTransform {
  // required
  optional string name = 1;

  message SubParam {
    // required
    optional string key = 1;
    optional string value = 2;
  }
  repeated SubParam subparam = 2;
}