Revert "Merge pull request #1831 from woolsweater/the-trail-is-closed"

This reverts commit 21dfaf0, reversing
changes made to f900b4e.

Author: ahoppen

Sources/SourceKitLSP/CMakeLists.txt

@@ -26,7 +26,6 @@ target_sources(SourceKitLSP PRIVATE
 )
 target_sources(SourceKitLSP PRIVATE
   Swift/AdjustPositionToStartOfIdentifier.swift
-  Swift/ClosureCompletionFormat.swift
   Swift/CodeActions/AddDocumentation.swift
   Swift/CodeActions/ConvertIntegerLiteral.swift
   Swift/CodeActions/ConvertJSONToCodableStruct.swift

Sources/SourceKitLSP/Swift/ClosureCompletionFormat.swift

@@ -323,14 +323,9 @@ class CodeCompletionSession {
     var parser = Parser(exprToExpand)
     let expr = ExprSyntax.parse(from: &parser)
     guard let call = OutermostFunctionCallFinder.findOutermostFunctionCall(in: expr),
-      let expandedCall = ExpandEditorPlaceholdersToLiteralClosures.refactor(
+      let expandedCall = ExpandEditorPlaceholdersToTrailingClosures.refactor(
         syntax: call,
-        in: ExpandEditorPlaceholdersToLiteralClosures.Context(
-          format: .custom(
-            ClosureCompletionFormat(indentationWidth: indentationWidth),
-            allowNestedPlaceholders: true
-          )
-        )
+        in: ExpandEditorPlaceholdersToTrailingClosures.Context(indentationWidth: indentationWidth)
       )
     else {
       return nil
@@ -339,7 +334,7 @@ class CodeCompletionSession {
     let bytesToExpand = Array(exprToExpand.utf8)
 
     var expandedBytes: [UInt8] = []
-    // Add the prefix that we stripped off to allow expression parsing
+    // Add the prefix that we stripped of to allow expression parsing
     expandedBytes += strippedPrefix.utf8
     // Add any part of the expression that didn't end up being part of the function call
     expandedBytes += bytesToExpand[0..<call.position.utf8Offset]

Sources/SourceKitLSP/Swift/CodeCompletionSession.swift

@@ -14,166 +14,34 @@ import Foundation
 import SKLogging
 @_spi(RawSyntax) import SwiftSyntax
 
-/// Translate SourceKit placeholder syntax — `<#foo#>` — in `input` to LSP
-/// placeholder syntax: `${n:foo}`.
-///
-/// If `clientSupportsSnippets` is `false`, the placeholder is rendered as an
-/// empty string, to prevent the client from inserting special placeholder
-/// characters as if they were literal text.
-@_spi(Testing)
-public func rewriteSourceKitPlaceholders(in input: String, clientSupportsSnippets: Bool) -> String {
-  var result = ""
-  var nextPlaceholderNumber = 1
-  // Current stack of nested placeholders, most nested last. Each element needs
-  // to be rendered inside the element before it.
-  var placeholders: [(number: Int, contents: String)] = []
-  let tokens = tokenize(input)
-  for token in tokens {
-    switch token {
-    case let .text(text):
-      if placeholders.isEmpty {
-        result += text
-      } else {
-        placeholders.latest.contents += text
-      }
-
-    case let .curlyBrace(brace):
-      if placeholders.isEmpty {
-        result.append(brace)
-      } else {
-        // Braces are only escaped _inside_ a placeholder; otherwise the client
-        // would include the backslashes literally.
-        placeholders.latest.contents.append(contentsOf: ["\\", brace])
-      }
-
-    case .placeholderOpen:
-      placeholders.append((number: nextPlaceholderNumber, contents: ""))
-      nextPlaceholderNumber += 1
-
-    case .placeholderClose:
-      guard let (number, placeholderBody) = placeholders.popLast() else {
-        logger.fault("Invalid placeholder in \(input)")
-        return input
-      }
-      guard let displayName = nameForSnippet(placeholderBody) else {
-        logger.fault("Failed to decode placeholder \(placeholderBody) in \(input)")
-        return input
-      }
-      let placeholder =
-        clientSupportsSnippets
-        ? formatLSPPlaceholder(displayName, number: number)
-        : ""
-      if placeholders.isEmpty {
-        result += placeholder
-      } else {
-        placeholders.latest.contents += placeholder
-      }
-    }
-  }
-
-  return result
-}
-
-/// Scan `input` to identify special elements within: curly braces, which may
-/// need to be escaped; and SourceKit placeholder open/close delimiters.
-private func tokenize(_ input: String) -> [SnippetToken] {
-  var index = input.startIndex
-  var isAtEnd: Bool { index == input.endIndex }
-  func match(_ char: Character) -> Bool {
-    if isAtEnd || input[index] != char {
-      return false
-    } else {
-      input.formIndex(after: &index)
-      return true
+func rewriteSourceKitPlaceholders(in string: String, clientSupportsSnippets: Bool) -> String {
+  var result = string
+  var index = 1
+  while let start = result.range(of: "<#") {
+    guard let end = result[start.upperBound...].range(of: "#>") else {
+      logger.fault("Invalid placeholder in \(string)")
+      return string
     }
-  }
-  func next() -> Character? {
-    guard !isAtEnd else { return nil }
-    defer { input.formIndex(after: &index) }
-    return input[index]
-  }
-
-  var tokens: [SnippetToken] = []
-  var text = ""
-  while let char = next() {
-    switch char {
-    case "<":
-      if match("#") {
-        tokens.append(.text(text))
-        text.removeAll()
-        tokens.append(.placeholderOpen)
-      } else {
-        text.append(char)
-      }
-
-    case "#":
-      if match(">") {
-        tokens.append(.text(text))
-        text.removeAll()
-        tokens.append(.placeholderClose)
-      } else {
-        text.append(char)
-      }
-
-    case "{", "}":
-      tokens.append(.text(text))
-      text.removeAll()
-      tokens.append(.curlyBrace(char))
-
-    case let c:
-      text.append(c)
+    let rawPlaceholder = String(result[start.lowerBound..<end.upperBound])
+    guard let displayName = nameForSnippet(rawPlaceholder) else {
+      logger.fault("Failed to decode placeholder \(rawPlaceholder) in \(string)")
+      return string
     }
+    let snippet = clientSupportsSnippets ? "${\(index):\(displayName)}" : ""
+    result.replaceSubrange(start.lowerBound..<end.upperBound, with: snippet)
+    index += 1
   }
-
-  tokens.append(.text(text))
-
-  return tokens
-}
-
-/// A syntactical element inside a SourceKit snippet.
-private enum SnippetToken {
-  /// A placeholder delimiter.
-  case placeholderOpen, placeholderClose
-  /// One of '{' or '}', which may need to be escaped in the output.
-  case curlyBrace(Character)
-  /// Any other consecutive run of characters from the input, which needs no
-  /// special treatment.
-  case text(String)
+  return result
 }
 
-/// Given the interior text of a SourceKit placeholder, extract a display name
-/// suitable for a LSP snippet.
-private func nameForSnippet(_ body: String) -> String? {
-  var text = rewrappedAsPlaceholder(body)
+/// Parse a SourceKit placeholder and extract the display name suitable for a
+/// LSP snippet.
+fileprivate func nameForSnippet(_ text: String) -> String? {
+  var text = text
   return text.withSyntaxText {
     guard let data = RawEditorPlaceholderData(syntaxText: $0) else {
       return nil
     }
     return String(syntaxText: data.typeForExpansionText ?? data.displayText)
   }
 }
-
-private let placeholderStart = "<#"
-private let placeholderEnd = "#>"
-private func rewrappedAsPlaceholder(_ body: String) -> String {
-  return placeholderStart + body + placeholderEnd
-}
-
-/// Wrap `body` in LSP snippet placeholder syntax, using `number` as the
-/// placeholder's index in the snippet.
-private func formatLSPPlaceholder(_ body: String, number: Int) -> String {
-  "${\(number):\(body)}"
-}
-
-private extension Array {
-  /// Mutable access to the final element of an array.
-  ///
-  /// - precondition: The array must not be empty.
-  var latest: Element {
-    get { self.last! }
-    _modify {
-      let index = self.index(before: self.endIndex)
-      yield &self[index]
-    }
-  }
-}