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0f18948bd5
Allow the declaration of @objc async methods, mapping them to a completion-handler API in Objective-C. This covers most of the checking and semantics within the type checker: * Declaring @objc async methods and checking their parameter/result types * Determining the default Objective-C selector by adding completionHandler/WithCompletionHandler as appropriate * Determining the type of the completion handler parameter * Inferring @objc from protocol requirements * Inferring @objc from an overridden method
125 lines
4.4 KiB
C++
125 lines
4.4 KiB
C++
//===--- ForeignAsyncConvention.h - Async conventions -----------*- C++ -*-===//
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//
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// This source file is part of the Swift.org open source project
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//
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// Copyright (c) 2014 - 2020 Apple Inc. and the Swift project authors
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// Licensed under Apache License v2.0 with Runtime Library Exception
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//
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// See https://swift.org/LICENSE.txt for license information
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// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
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//
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//===----------------------------------------------------------------------===//
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//
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// This file defines the ForeignAsyncConvention structure, which
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// describes the rules for how to detect that a foreign API is asynchronous.
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//
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//===----------------------------------------------------------------------===//
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#ifndef SWIFT_FOREIGN_ASYNC_CONVENTION_H
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#define SWIFT_FOREIGN_ASYNC_CONVENTION_H
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#include "swift/AST/Type.h"
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namespace swift {
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/// A small structure describing the async convention of a foreign declaration.
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class ForeignAsyncConvention {
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public:
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struct Info {
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/// The index of the completion handler parameters.
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unsigned CompletionHandlerParamIndex;
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/// When non-zero, indicates which parameter to the completion handler is
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/// the Error? parameter (minus one) that makes this async function also
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/// throwing.
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unsigned CompletionHandlerErrorParamIndex;
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Info()
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: CompletionHandlerParamIndex(0), CompletionHandlerErrorParamIndex(0) { }
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Info(
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unsigned completionHandlerParamIndex,
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Optional<unsigned> completionHandlerErrorParamIndex)
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: CompletionHandlerParamIndex(completionHandlerParamIndex),
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CompletionHandlerErrorParamIndex(
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completionHandlerErrorParamIndex
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? *completionHandlerErrorParamIndex + 1
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: 0) {}
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/// Retrieve the index of the \c Error? parameter in the completion handler's
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/// parameter list. When argument passed to this parameter is non-null, the
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/// provided error will be thrown by the async function.
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Optional<unsigned> completionHandlerErrorParamIndex() const {
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if (CompletionHandlerErrorParamIndex == 0)
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return None;
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return CompletionHandlerErrorParamIndex - 1;
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}
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/// Whether the async function is throwing due to the completion handler
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/// having an \c Error? parameter.
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///
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/// Equivalent to \c static_cast<bool>(completionHandlerErrorParamIndex()).
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bool isThrowing() const {
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return CompletionHandlerErrorParamIndex != 0;
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}
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};
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/// The type of the completion handler parameter.
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CanType CompletionHandlerType;
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/// Information about the async convention that can be determined from an
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/// Objective-C declaration by itself.
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Info TheInfo;
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public:
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ForeignAsyncConvention() : TheInfo() { }
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ForeignAsyncConvention(CanType completionHandlerType,
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unsigned completionHandlerParamIndex,
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Optional<unsigned> completionHandlerErrorParamIndex)
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: CompletionHandlerType(completionHandlerType),
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TheInfo(completionHandlerParamIndex, completionHandlerErrorParamIndex)
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{ }
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/// Retrieve the type of the completion handler parameter.
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CanType completionHandlerType() const { return CompletionHandlerType; }
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/// Retrieve the index of the completion handler parameter, which will be
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/// erased from the Swift signature of the imported async function.
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unsigned completionHandlerParamIndex() const {
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return TheInfo.CompletionHandlerParamIndex;
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}
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/// Retrieve the index of the \c Error? parameter in the completion handler's
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/// parameter list. When argument passed to this parameter is non-null, the
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/// provided error will be thrown by the async function.
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Optional<unsigned> completionHandlerErrorParamIndex() const {
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return TheInfo.completionHandlerErrorParamIndex();
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}
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/// Whether the async function is throwing due to the completion handler
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/// having an \c Error? parameter.
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///
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/// Equivalent to \c static_cast<bool>(completionHandlerErrorParamIndex()).
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bool isThrowing() const {
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return TheInfo.isThrowing();
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}
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bool operator==(ForeignAsyncConvention other) const {
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return CompletionHandlerType == other.CompletionHandlerType
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&& TheInfo.CompletionHandlerParamIndex ==
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other.TheInfo.CompletionHandlerParamIndex
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&& TheInfo.CompletionHandlerErrorParamIndex ==
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other.TheInfo.CompletionHandlerErrorParamIndex;
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}
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bool operator!=(ForeignAsyncConvention other) const {
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return !(*this == other);
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}
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};
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}
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#endif
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