1313/// Represents a source location in a Swift file.
1414public struct SourceLocation : Hashable , Codable , CustomDebugStringConvertible {
1515
16- /// The UTF-8 byte offset into the file where this location resides.
17- public let offset : Int
18-
1916 /// The line in the file where this location resides. 1-based.
17+ ///
18+ /// ### See also
19+ /// ``SourceLocation/presumedLine``
2020 public var line : Int
2121
2222 /// The UTF-8 byte offset from the beginning of the line where this location
2323 /// resides. 1-based.
2424 public let column : Int
2525
26+ /// The UTF-8 byte offset into the file where this location resides.
27+ public let offset : Int
28+
2629 /// The file in which this location resides.
30+ ///
31+ /// ### See also
32+ /// ``SourceLocation/presumedFile``
2733 public let file : String
2834
35+ /// The line of this location when respecting `#sourceLocation` directives.
36+ ///
37+ /// If the location hasn’t been adjusted using `#sourceLocation` directives,
38+ /// this is the same as `file`.
39+ public let presumedLine : Int
40+
41+ /// The file in which the the location resides when respecting `#sourceLocation`
42+ /// directives.
43+ ///
44+ /// If the location has been adjusted using `#sourceLocation` directives, this
45+ /// is the file mentioned in the last `#sourceLocation` directive before this
46+ /// location, otherwise this is the same as `file`.
47+ public let presumedFile : String
48+
2949 /// Returns the location as `<line>:<column>` for debugging purposes.
3050 /// Do not rely on this output being stable.
3151 public var debugDescription : String {
@@ -47,11 +67,26 @@ public struct SourceLocation: Hashable, Codable, CustomDebugStringConvertible {
4767 /// location in the source file has `offset` 0.
4868 /// - file: A string describing the name of the file in which this location
4969 /// is contained.
50- public init ( line: Int , column: Int , offset: Int , file: String ) {
70+ /// - presumedLine: If the location has been adjusted using `#sourceLocation`
71+ /// directives, the adjusted line. If `nil`, this defaults to
72+ /// `line`.
73+ /// - presumedFile: If the location has been adjusted using `#sourceLocation`
74+ /// directives, the adjusted file. If `nil`, this defaults to
75+ /// `file`.
76+ public init (
77+ line: Int ,
78+ column: Int ,
79+ offset: Int ,
80+ file: String ,
81+ presumedLine: Int ? = nil ,
82+ presumedFile: String ? = nil
83+ ) {
5184 self . line = line
5285 self . offset = offset
5386 self . column = column
5487 self . file = file
88+ self . presumedLine = presumedLine ?? line
89+ self . presumedFile = presumedFile ?? file
5590 }
5691}
5792
@@ -83,6 +118,22 @@ public struct SourceRange: Hashable, Codable, CustomDebugStringConvertible {
83118 }
84119}
85120
121+ /// Collects all `PoundSourceLocationSyntax` directives in a file.
122+ fileprivate class SourceLocationCollector : SyntaxVisitor {
123+ private var sourceLocationDirectives : [ PoundSourceLocationSyntax ] = [ ]
124+
125+ override func visit( _ node: PoundSourceLocationSyntax ) -> SyntaxVisitorContinueKind {
126+ sourceLocationDirectives. append ( node)
127+ return . skipChildren
128+ }
129+
130+ static func collectSourceLocations( in tree: some SyntaxProtocol ) -> [ PoundSourceLocationSyntax ] {
131+ let collector = SourceLocationCollector ( viewMode: . sourceAccurate)
132+ collector. walk ( tree)
133+ return collector. sourceLocationDirectives
134+ }
135+ }
136+
86137/// Converts ``AbsolutePosition``s of syntax nodes to ``SourceLocation``s, and
87138/// vice-versa. The ``AbsolutePosition``s must be originating from nodes that are
88139/// part of the same tree that was used to initialize this class.
@@ -95,6 +146,15 @@ public final class SourceLocationConverter {
95146 /// Position at end of file.
96147 let endOfFile : AbsolutePosition
97148
149+ /// The information from all `#sourceLocation` directives in the file
150+ /// necessary to compute presumed locations.
151+ ///
152+ /// - `sourceLine` is the line at which the `#sourceLocation` statement occurs
153+ /// within the current file.
154+ /// - `fileArgument` is the `file` argument of the `#sourceLocation` directive.
155+ /// - `lineArgument` is the `line` argument of the `#sourceLocation` directive.
156+ var sourceLocationDirectives : [ ( sourceLine: Int , arguments: ( file: String , line: Int ) ? ) ] = [ ]
157+
98158 /// - Parameters:
99159 /// - file: The file path associated with the syntax tree.
100160 /// - tree: The root of the syntax tree to convert positions to line/columns for.
@@ -104,11 +164,31 @@ public final class SourceLocationConverter {
104164 self . source = tree. syntaxTextBytes
105165 ( self . lines, endOfFile) = computeLines ( tree: Syntax ( tree) )
106166 precondition ( tree. byteSize == endOfFile. utf8Offset)
167+
168+ for directive in SourceLocationCollector . collectSourceLocations ( in: tree) {
169+ let location = self . physicalLocation ( for: directive. positionAfterSkippingLeadingTrivia)
170+ if let args = directive. args {
171+ let logicalFile = args. fileName. segments. description
172+ guard let logicalLine = Int ( args. lineNumber. description) else {
173+ // FIXME: Handle hex line numbers
174+ continue
175+ }
176+ sourceLocationDirectives. append ( ( sourceLine: location. line, arguments: ( file: logicalFile, line: logicalLine) ) )
177+ } else {
178+ // `#sourceLocation()` without any arguments resets the `#sourceLocation` directive.
179+ sourceLocationDirectives. append ( ( sourceLine: location. line, arguments: nil ) )
180+ }
181+ }
107182 }
108183
184+ /// - Important: This initializer does not take `#sourceLocation` directives
185+ /// into account and doesn’t produce `presumedFile` and
186+ /// `presumedLine`.
187+ ///
109188 /// - Parameters:
110189 /// - file: The file path associated with the syntax tree.
111190 /// - source: The source code to convert positions to line/columns for.
191+ @available ( * , deprecated, message: " Use init(file:tree:) instead " )
112192 public init ( file: String , source: String ) {
113193 self . file = file
114194 self . source = Array ( source. utf8)
@@ -145,13 +225,40 @@ public final class SourceLocationConverter {
145225 }
146226 }
147227
148- /// Convert a ``AbsolutePosition`` to a ``SourceLocation``. If the position is
228+ /// Convert a ``AbsolutePosition`` to a ``SourceLocation``.
229+ ///
230+ /// If the position is exceeding the file length then the ``SourceLocation``
231+ /// for the end of file is returned. If position is negative the location for
232+ /// start of file is returned.
233+ public func location( for position: AbsolutePosition ) -> SourceLocation {
234+ let physicalLocation = physicalLocation ( for: position)
235+ if let lastSourceLocationDirective = sourceLocationDirectives. last ( where: { $0. sourceLine < physicalLocation. line } ) ,
236+ let arguments = lastSourceLocationDirective. arguments
237+ {
238+ let presumedLine = arguments. line + physicalLocation. line - lastSourceLocationDirective. sourceLine - 1
239+ return SourceLocation (
240+ line: physicalLocation. line,
241+ column: physicalLocation. column,
242+ offset: physicalLocation. offset,
243+ file: physicalLocation. file,
244+ presumedLine: presumedLine,
245+ presumedFile: arguments. file
246+ )
247+ }
248+
249+ return physicalLocation
250+ }
251+
252+ /// Compute the location of `position` without taking `#sourceLocation`
253+ /// directives into account.
254+ ///
255+ /// If the position is
149256 /// exceeding the file length then the ``SourceLocation`` for the end of file
150257 /// is returned. If position is negative the location for start of file is
151258 /// returned.
152- public func location ( for origpos : AbsolutePosition ) -> SourceLocation {
259+ private func physicalLocation ( for position : AbsolutePosition ) -> SourceLocation {
153260 // Clamp the given position to the end of file if needed.
154- let pos = min ( origpos , endOfFile)
261+ let pos = min ( position , endOfFile)
155262 if pos. utf8Offset < 0 {
156263 return SourceLocation ( line: 1 , column: 1 , offset: 0 , file: self . file)
157264 }
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