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| 1 | +//===----------------------------------------------------------------------===// |
| 2 | +// |
| 3 | +// This source file is part of the Swift.org open source project |
| 4 | +// |
| 5 | +// Copyright (c) 2014 - 2022 Apple Inc. and the Swift project authors |
| 6 | +// Licensed under Apache License v2.0 with Runtime Library Exception |
| 7 | +// |
| 8 | +// See https://swift.org/LICENSE.txt for license information |
| 9 | +// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors |
| 10 | +// |
| 11 | +//===----------------------------------------------------------------------===// |
| 12 | + |
| 13 | +import SwiftDiagnostics |
| 14 | +import SwiftSyntax |
| 15 | + |
| 16 | +/// An implementation of the `MacroExpansionContext` protocol that is |
| 17 | +/// suitable for testing purposes. |
| 18 | +public class BasicMacroExpansionContext { |
| 19 | + /// A single source file that is known to the macro expansion context. |
| 20 | + public struct KnownSourceFile { |
| 21 | + /// The name of the module in which this source file resides. |
| 22 | + let moduleName: String |
| 23 | + |
| 24 | + /// The full path to the file. |
| 25 | + let fullFilePath: String |
| 26 | + |
| 27 | + public init(moduleName: String, fullFilePath: String) { |
| 28 | + self.moduleName = moduleName |
| 29 | + self.fullFilePath = fullFilePath |
| 30 | + } |
| 31 | + } |
| 32 | + |
| 33 | + /// Create a new macro evaluation context. |
| 34 | + public init( |
| 35 | + expansionDiscriminator: String = "__macro_local_", |
| 36 | + sourceFiles: [SourceFileSyntax: KnownSourceFile] = [:] |
| 37 | + ) { |
| 38 | + self.expansionDiscriminator = expansionDiscriminator |
| 39 | + self.sourceFiles = sourceFiles |
| 40 | + } |
| 41 | + |
| 42 | + /// The set of diagnostics that were emitted as part of expanding the |
| 43 | + /// macro. |
| 44 | + public private(set) var diagnostics: [Diagnostic] = [] |
| 45 | + |
| 46 | + /// Mapping from the root source file syntax nodes to the known source-file |
| 47 | + /// information about that source file. |
| 48 | + private var sourceFiles: [SourceFileSyntax: KnownSourceFile] = [:] |
| 49 | + |
| 50 | + /// Mapping from intentionally-disconnected syntax node roots to the |
| 51 | + /// absolute offsets that have within a given source file, which is used |
| 52 | + /// to establish the link between a node that been intentionally disconnected |
| 53 | + /// from a source file to hide information from the macro implementation. |
| 54 | + private var disconnectedNodes: [Syntax: (SourceFileSyntax, Int)] = [:] |
| 55 | + |
| 56 | + /// The macro expansion discriminator, which is used to form unique names |
| 57 | + /// when requested. |
| 58 | + /// |
| 59 | + /// The expansion discriminator is combined with the `uniqueNames` counters |
| 60 | + /// to produce unique names. |
| 61 | + private var expansionDiscriminator: String = "" |
| 62 | + |
| 63 | + /// Counter for each of the uniqued names. |
| 64 | + /// |
| 65 | + /// Used in conjunction with `expansionDiscriminator`. |
| 66 | + private var uniqueNames: [String: Int] = [:] |
| 67 | + |
| 68 | +} |
| 69 | + |
| 70 | +extension BasicMacroExpansionContext { |
| 71 | + /// Note that the given node that was at the given position in the provided |
| 72 | + /// source file has been disconnected and is now a new root. |
| 73 | + private func addDisconnected<Node: SyntaxProtocol>( |
| 74 | + _ node: Node, |
| 75 | + at offset: AbsolutePosition, |
| 76 | + in sourceFile: SourceFileSyntax |
| 77 | + ) { |
| 78 | + disconnectedNodes[Syntax(node)] = (sourceFile, offset.utf8Offset) |
| 79 | + } |
| 80 | + |
| 81 | + /// Detach the given node, and record where it came from. |
| 82 | + public func detach<Node: SyntaxProtocol>(_ node: Node) -> Node { |
| 83 | + let detached = node.detach() |
| 84 | + |
| 85 | + if let rootSourceFile = node.root.as(SourceFileSyntax.self) { |
| 86 | + addDisconnected(detached, at: node.position, in: rootSourceFile) |
| 87 | + } |
| 88 | + |
| 89 | + return detached |
| 90 | + } |
| 91 | +} |
| 92 | + |
| 93 | +extension String { |
| 94 | + /// Retrieve the base name of a string that represents a path, removing the |
| 95 | + /// directory. |
| 96 | + fileprivate var basename: String { |
| 97 | + guard let lastSlash = lastIndex(of: "/") else { |
| 98 | + return self |
| 99 | + } |
| 100 | + |
| 101 | + return String(self[index(after: lastSlash)...]) |
| 102 | + } |
| 103 | + |
| 104 | +} |
| 105 | +extension BasicMacroExpansionContext: MacroExpansionContext { |
| 106 | + /// Generate a unique name for use in the macro. |
| 107 | + public func createUniqueName(_ providedName: String) -> TokenSyntax { |
| 108 | + // If provided with an empty name, substitute in something. |
| 109 | + let name = providedName.isEmpty ? "__local" : providedName |
| 110 | + |
| 111 | + // Grab a unique index value for this name. |
| 112 | + let uniqueIndex = uniqueNames[name, default: 0] |
| 113 | + uniqueNames[name] = uniqueIndex + 1 |
| 114 | + |
| 115 | + // Start with the expansion discriminator. |
| 116 | + var resultString = expansionDiscriminator |
| 117 | + |
| 118 | + // Mangle the name |
| 119 | + resultString += "\(name.count)\(name)" |
| 120 | + |
| 121 | + // Mangle the operator for unique macro names. |
| 122 | + resultString += "fMu" |
| 123 | + |
| 124 | + // Mangle the index. |
| 125 | + if uniqueIndex == 0 { |
| 126 | + resultString += "_" |
| 127 | + } else { |
| 128 | + resultString += "\(uniqueIndex - 1)" |
| 129 | + } |
| 130 | + |
| 131 | + return TokenSyntax(.identifier(resultString), presence: .present) |
| 132 | + } |
| 133 | + |
| 134 | + /// Produce a diagnostic while expanding the macro. |
| 135 | + public func diagnose(_ diagnostic: Diagnostic) { |
| 136 | + diagnostics.append(diagnostic) |
| 137 | + } |
| 138 | + |
| 139 | + public func location<Node: SyntaxProtocol>( |
| 140 | + of node: Node, |
| 141 | + at position: PositionInSyntaxNode, |
| 142 | + filePathMode: SourceLocationFilePathMode |
| 143 | + ) -> SourceLocation? { |
| 144 | + // Dig out the root source file and figure out how we need to adjust the |
| 145 | + // offset of the given syntax node to adjust for it. |
| 146 | + let rootSourceFile: SourceFileSyntax |
| 147 | + let offsetAdjustment: Int |
| 148 | + if let directRootSourceFile = node.root.as(SourceFileSyntax.self) { |
| 149 | + // The syntax node came from the source file itself. |
| 150 | + rootSourceFile = directRootSourceFile |
| 151 | + offsetAdjustment = 0 |
| 152 | + } else if let (adjustedSourceFile, offset) = disconnectedNodes[Syntax(node)] { |
| 153 | + // The syntax node came from a disconnected root, so adjust for that. |
| 154 | + rootSourceFile = adjustedSourceFile |
| 155 | + offsetAdjustment = offset |
| 156 | + } else { |
| 157 | + return nil |
| 158 | + } |
| 159 | + |
| 160 | + guard let knownRoot = sourceFiles[rootSourceFile] else { |
| 161 | + return nil |
| 162 | + } |
| 163 | + |
| 164 | + // Determine the filename to use in the resulting location. |
| 165 | + let fileName: String |
| 166 | + switch filePathMode { |
| 167 | + case .fileID: |
| 168 | + fileName = "\(knownRoot.moduleName)/\(knownRoot.fullFilePath.basename)" |
| 169 | + |
| 170 | + case .filePath: |
| 171 | + fileName = knownRoot.fullFilePath |
| 172 | + } |
| 173 | + |
| 174 | + // Find the node's offset relative to its root. |
| 175 | + let rawPosition: AbsolutePosition |
| 176 | + switch position { |
| 177 | + case .beforeLeadingTrivia: |
| 178 | + rawPosition = node.position |
| 179 | + |
| 180 | + case .afterLeadingTrivia: |
| 181 | + rawPosition = node.positionAfterSkippingLeadingTrivia |
| 182 | + |
| 183 | + case .beforeTrailingTrivia: |
| 184 | + rawPosition = node.endPositionBeforeTrailingTrivia |
| 185 | + |
| 186 | + case .afterTrailingTrivia: |
| 187 | + rawPosition = node.endPosition |
| 188 | + } |
| 189 | + |
| 190 | + // Do the location lookup. |
| 191 | + let converter = SourceLocationConverter(file: fileName, tree: rootSourceFile) |
| 192 | + return converter.location(for: rawPosition.advanced(by: offsetAdjustment)) |
| 193 | + } |
| 194 | +} |
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