/*
 * Copyright 2016 The Kythe Authors. All rights reserved.
 *
 * 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 = "proto3";

package kythe.proto;

option go_package = "storage_service_go_proto";
option java_package = "com.google.devtools.kythe.proto";

import "kythe/proto/storage.proto";

// Persistent storage server for Kythe analysis data.
// See: http://www.kythe.io/docs/kythe-storage.html
service GraphStore {
  // Read responds with all Entry messages that match the given ReadRequest.
  // The Read operation should be implemented with time complexity proportional
  // to the size of the return set.
  rpc Read(ReadRequest) returns (stream Entry) {}

  // Scan responds with all Entry messages matching the given ScanRequest.  If a
  // ScanRequest field is empty, any entry value for that field matches and will
  // be returned.  Scan is similar to Read, but with no time complexity
  // restrictions.
  rpc Scan(ScanRequest) returns (stream Entry) {}

  // Write atomically inserts or updates a collection of entries into the store.
  // Each update is a tuple of the form (kind, target, fact, value).  For each
  // such update, an entry (source, kind, target, fact, value) is written into
  // the store, replacing any existing entry (source, kind, target, fact,
  // value') that may exist.  Note that this operation cannot delete any data
  // from the store; entries are only ever inserted or updated.  Apart from
  // acting atomically, no other constraints are placed on the implementation.
  rpc Write(WriteRequest) returns (WriteReply) {}
}

// ShardedGraphStores can be arbitrarily sharded for parallel processing.
// Depending on the implementation, these methods may not return consistent
// results when the store is being written to.  Shards are indexed from 0.
service ShardedGraphStore {
  // Count returns the number of entries in the given shard.
  rpc Count(CountRequest) returns (CountReply) {}

  // Shard responds with each Entry in the given shard.
  rpc Shard(ShardRequest) returns (stream Entry) {}
}