51 lines
2.2 KiB
Swift
51 lines
2.2 KiB
Swift
//===----------------------------------------------------------------------===//
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//
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// This source file is part of the SwiftNIO open source project
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//
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// Copyright (c) 2017-2021 Apple Inc. and the SwiftNIO project authors
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// Licensed under Apache License v2.0
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//
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// See LICENSE.txt for license information
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// See CONTRIBUTORS.txt for the list of SwiftNIO project authors
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//
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// SPDX-License-Identifier: Apache-2.0
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//
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//===----------------------------------------------------------------------===//
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import NIOCore
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/// A protocol that covers an object that does DNS lookups.
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///
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/// In general the rules for the resolver are relatively broad: there are no specific requirements on how
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/// it operates. However, the rest of the code assumes that it obeys RFC 6724, particularly section 6 on
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/// ordering returned addresses. That is, the IPv6 and IPv4 responses should be ordered by the destination
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/// address ordering rules from that RFC. This specification is widely implemented by getaddrinfo
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/// implementations, so any implementation based on getaddrinfo will work just fine. In the future, a custom
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/// resolver will need also to implement these sorting rules.
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public protocol Resolver {
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/// Initiate a DNS A query for a given host.
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///
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/// - parameters:
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/// - host: The hostname to do an A lookup on.
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/// - port: The port we'll be connecting to.
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/// - returns: An `EventLoopFuture` that fires with the result of the lookup.
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func initiateAQuery(host: String, port: Int) -> EventLoopFuture<[SocketAddress]>
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/// Initiate a DNS AAAA query for a given host.
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///
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/// - parameters:
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/// - host: The hostname to do an AAAA lookup on.
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/// - port: The port we'll be connecting to.
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/// - returns: An `EventLoopFuture` that fires with the result of the lookup.
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func initiateAAAAQuery(host: String, port: Int) -> EventLoopFuture<[SocketAddress]>
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/// Cancel all outstanding DNS queries.
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///
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/// This method is called whenever queries that have not completed no longer have their
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/// results needed. The resolver should, if possible, abort any outstanding queries and
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/// clean up their state.
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///
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/// This method is not guaranteed to terminate the outstanding queries.
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func cancelQueries()
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}
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