Merge pull request #1900 from StevenWong12/replace_delegate_with_closure

Replace `IncrementalParseReusedNodeDelegate` with `ReusedNodeCallback`

Author: ahoppen

Sources/SwiftParser/IncrementalParseTransition.swift

@@ -35,61 +35,39 @@ extension Parser {
   }
 }
 
-/// Accepts the re-used ``Syntax`` nodes that `IncrementalParseTransition`
+/// Accepts a re-used ``Syntax`` node that `IncrementalParseTransition`
 /// determined they should be re-used for a parse invocation.
 ///
 /// The client can use this information to potentially avoid unnecessary work
 /// for regions of the source that have not changed.
 ///
 /// This is also used for testing purposes to ensure incremental reparsing
 /// worked as expected.
-public protocol IncrementalParseReusedNodeDelegate {
-  /// Accepts ``Syntax`` node of skipped source region.
-  ///
-  /// - Parameters:
-  ///   - previousNode: The node from the previous tree that is associated with
-  ///                   the skipped source region.
-  func parserReusedNode(previousNode: Syntax)
-}
-
-/// An implementation of `IncrementalParseReusedNodeDelegate` that just collects
-/// the range and re-used node into an array.
-public final class IncrementalParseReusedNodeCollector:
-  IncrementalParseReusedNodeDelegate
-{
-  public var nodes: [Syntax] = []
-
-  public init() {}
-
-  public func parserReusedNode(previousNode: Syntax) {
-    nodes.append(previousNode)
-  }
-}
+public typealias ReusedNodeCallback = (_ node: Syntax) -> ()
 
 /// Keeps track of a previously parsed syntax tree and the source edits that
 /// occurred since it was created.
 public final class IncrementalParseTransition {
   fileprivate let previousTree: SourceFileSyntax
   fileprivate let edits: ConcurrentEdits
   fileprivate let lookaheadRanges: LookaheadRanges
-  fileprivate let reusedDelegate: IncrementalParseReusedNodeDelegate?
+  fileprivate let reusedNodeCallback: ReusedNodeCallback?
 
   /// - Parameters:
   ///   - previousTree: The previous tree to do lookups on.
   ///   - edits: The edits that have occurred since the last parse that resulted
   ///            in the new source that is about to be parsed.
-  ///   - reusedNodeDelegate: Optional delegate to accept information about the
-  ///                         reused regions and nodes.
+  ///   - reusedNodeCallback: Optional closure to accept information about the re-used node. For each node that gets re-used `reusedNodeCallback` is called.
   public init(
     previousTree: SourceFileSyntax,
     edits: ConcurrentEdits,
     lookaheadRanges: LookaheadRanges,
-    reusedNodeDelegate: IncrementalParseReusedNodeDelegate? = nil
+    reusedNodeCallback: ReusedNodeCallback? = nil
   ) {
     self.previousTree = previousTree
     self.edits = edits
     self.lookaheadRanges = lookaheadRanges
-    self.reusedDelegate = reusedNodeDelegate
+    self.reusedNodeCallback = reusedNodeCallback
   }
 }
 
@@ -110,8 +88,8 @@ struct IncrementalParseLookup {
     return transition.edits
   }
 
-  fileprivate var reusedDelegate: IncrementalParseReusedNodeDelegate? {
-    return transition.reusedDelegate
+  fileprivate var reusedCallback: ReusedNodeCallback? {
+    return transition.reusedNodeCallback
   }
 
   /// Does a lookup to see if the current source `offset` should be associated
@@ -132,10 +110,8 @@ struct IncrementalParseLookup {
     }
     let prevPosition = AbsolutePosition(utf8Offset: prevOffset)
     let node = cursorLookup(prevPosition: prevPosition, kind: kind)
-    if let delegate = reusedDelegate, let node {
-      delegate.parserReusedNode(
-        previousNode: node
-      )
+    if let node {
+      reusedCallback?(node)
     }
     return node
   }

Sources/_SwiftSyntaxTestSupport/IncrementalParseTestUtils.swift

@@ -32,12 +32,12 @@ public func assertIncrementalParse(
 
   let (originalTree, lookaheadRanges) = Parser.parseIncrementally(source: originalString, parseTransition: nil)
 
-  let reusedNodesCollector = IncrementalParseReusedNodeCollector()
+  var reusedNodes: [Syntax] = []
   let transition = IncrementalParseTransition(
     previousTree: originalTree,
     edits: concurrentEdits,
     lookaheadRanges: lookaheadRanges,
-    reusedNodeDelegate: reusedNodesCollector
+    reusedNodeCallback: { reusedNodes.append($0) }
   )
 
   let newTree = Parser.parse(source: editedString)
@@ -66,11 +66,11 @@ public func assertIncrementalParse(
   }
 
   // Re-used nodes
-  if reusedNodesCollector.nodes.count != expectedReusedNodes.count {
+  if reusedNodes.count != expectedReusedNodes.count {
     XCTFail(
       """
-      Expected \(expectedReusedNodes.count) re-used nodes but received \(reusedNodesCollector.nodes.count):
-      \(reusedNodesCollector.nodes.map {$0.description}.joined(separator: "\n"))
+      Expected \(expectedReusedNodes.count) re-used nodes but received \(reusedNodes.count):
+      \(reusedNodes.map {$0.description}.joined(separator: "\n"))
       """,
       file: file,
       line: line
@@ -84,11 +84,11 @@ public func assertIncrementalParse(
       continue
     }
 
-    guard let reusedNode = reusedNodesCollector.nodes.first(where: { $0.byteRangeAfterTrimmingTrivia == range }) else {
+    guard let reusedNode = reusedNodes.first(where: { $0.byteRangeAfterTrimmingTrivia == range }) else {
       XCTFail(
         """
         Fail to match the range of \(expectedReusedNode.source) in:
-        \(reusedNodesCollector.nodes.map({"\($0.byteRangeAfterTrimmingTrivia): \($0.description)"}).joined(separator: "\n"))
+        \(reusedNodes.map({"\($0.byteRangeAfterTrimmingTrivia): \($0.description)"}).joined(separator: "\n"))
         """,
         file: expectedReusedNode.file,
         line: expectedReusedNode.line

Tests/SwiftParserTest/IncrementalParsingTests.swift

@@ -162,7 +162,6 @@ public class IncrementalParsingTests: XCTestCase {
   }
 
   public func testMultiEditMapping() throws {
-    try XCTSkipIf(true, "Swift parser does not handle node reuse yet")
     assertIncrementalParse(
       """
       let one: Int;let two: Int; let three: Int; ⏩️⏸️                      ⏪️⏩️⏸️   ⏪️let found: Int;let five: Int;