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//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2019 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//
import Foundation
import SwiftSyntax
/// The playground literals (`#colorLiteral`, `#fileLiteral`, and `#imageLiteral`) are forbidden.
///
/// Lint: Using a playground literal will yield a lint error with a suggestion of an API to replace
/// it.
@_spi(Rules)
public final class NoPlaygroundLiterals: SyntaxLintRule {
override public func visit(_ node: MacroExpansionExprSyntax) -> SyntaxVisitorContinueKind {
switch node.macroName.text {
case "colorLiteral":
diagnosedColorLiteralMacroExpansion(node)
case "fileLiteral":
diagnosedFileLiteralMacroExpansion(node)
case "imageLiteral":
diagnosedImageLiteralMacroExpansion(node)
default:
break
}
return .visitChildren
}
private func diagnosedColorLiteralMacroExpansion(_ node: MacroExpansionExprSyntax) {
guard isLiteralMacroCall(node, matchingLabels: ["red", "green", "blue", "alpha"]) else {
return
}
diagnose(.replaceColorLiteral, on: node)
}
private func diagnosedFileLiteralMacroExpansion(_ node: MacroExpansionExprSyntax) {
guard isLiteralMacroCall(node, matchingLabels: ["resourceName"]) else {
return
}
diagnose(.replaceFileLiteral, on: node)
}
private func diagnosedImageLiteralMacroExpansion(_ node: MacroExpansionExprSyntax) {
guard isLiteralMacroCall(node, matchingLabels: ["resourceName"]) else {
return
}
diagnose(.replaceImageLiteral, on: node)
}
/// Returns true if the given macro expansion is a correctly constructed call with the given
/// argument labels and has no trailing closures or generic arguments.
private func isLiteralMacroCall(
_ node: MacroExpansionExprSyntax,
matchingLabels labels: [String]
) -> Bool {
guard
node.genericArgumentClause == nil,
node.trailingClosure == nil,
node.additionalTrailingClosures.isEmpty,
node.arguments.count == labels.count
else {
return false
}
for (actual, expected) in zip(node.arguments, labels) {
guard actual.label?.text == expected else { return false }
}
return true
}
}
extension Finding.Message {
fileprivate static let replaceColorLiteral: Finding.Message =
"replace '#colorLiteral' with a call to an initializer on 'NSColor' or 'UIColor'"
fileprivate static let replaceFileLiteral: Finding.Message =
"replace '#fileLiteral' with a call to a method such as 'Bundle.url(forResource:withExtension:)'"
fileprivate static let replaceImageLiteral: Finding.Message =
"replace '#imageLiteral' with a call to an initializer on 'NSImage' or 'UIImage'"
}
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