naiveproxy/content/common/leveldb_wrapper.mojom
2018-01-28 13:32:06 -05:00

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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
module content.mojom;
import "components/leveldb/public/interfaces/leveldb.mojom";
// Gives information about changes to a LevelDB database.
// Note that observer methods are called before the callbacks for the
// LevelDBWrapper methods are run.
interface LevelDBObserver {
KeyAdded(array<uint8> key, array<uint8> value, string source);
KeyChanged(array<uint8> key, array<uint8> new_value, array<uint8> old_value,
string source);
KeyDeleted(array<uint8> key, array<uint8> old_value, string source);
AllDeleted(string source);
// Tells the client if it should send the old values for the key on Put() and
// Delete() calls for sending notifications. By default the clients are
// expected to send old values. It is set to true when the leveldb wrapper
// does not cache values in memory.
ShouldSendOldValueOnMutations(bool value);
};
struct KeyValue {
array<uint8> key;
array<uint8> value;
};
// Since the GetAll call is synchronous, LevelDBWrapper users need this
// asynchronously delivered notification to avoid applying changes to the
// returned array that it already contains. This is not sent over the
// normal LevelDBObserver interface as there can be many observers and
// only the connection that made the GetAll call needs to be notified of
// its completion.
interface LevelDBWrapperGetAllCallback {
Complete(bool success);
};
// A wrapper around leveldb that supports giving notifications when values
// change.
interface LevelDBWrapper {
AddObserver(associated LevelDBObserver observer);
// Set the database entry for |key| to |value|.
// Takes an optional |client_old_value| (see ShouldSendOldValueOnMutations()):
// 1. If the client is notified to not send old value on mutations
// |client_old_value| is unused and can be nullopt.
// 2. If the client is notified to send old values or not notified at all,
// |client_old_value| must be filled in with old value of the |key|, or
// nullopt if |key| was not present in database. This value is used to send
// notifications to LevelDBObserver(s).
// Returns OK on success.
Put(array<uint8> key, array<uint8> value, array<uint8>? client_old_value,
string source) =>
(bool success);
// Remove the database entry (if any) for |key|.
// Takes an optional |client_old_value| (see ShouldSendOldValueOnMutations()):
// 1. If the client is notified to not send old value on mutations,
// |client_old_value| is unused and can be nullopt.
// 2. If the client is notified to send old values or not notified at all,
// |client_old_value| must be filled in with old value of the |key|, or
// nullopt if |key| was not present in database. This value is used to send
// notifications to LevelDBObserver(s).
// Returns OK on success, and a non-OK status on error. It is not an error if
// |key| did not exist in the database.
Delete(array<uint8> key, array<uint8>? client_old_value, string source) =>
(bool success);
// Removes all the entries.
DeleteAll(string source) => (bool success);
// [DEPRECATED] Returns the value of the |key| only if values are
// stored in the internal in-memory cache. Fails if the |key| does not exist
// or if values are not required to be stored in the cache.
// TODO(ssid): Remove this function, crbug.com/764127.
Get(array<uint8> key) => (bool success, array<uint8> value);
// Returns all key/value pairs.
[Sync]
GetAll(associated LevelDBWrapperGetAllCallback complete_callback)
=> (leveldb.mojom.DatabaseError status, array<KeyValue> data);
};