Open and edit documents in syntactic-only mode in sourcekitd

With this change, opening and editing a document no longer causes a non-cancellable AST build. Instead, all semantic information is retrieved via requests that can be cancelled (after we implement cancellation).

Author: ahoppen

Sources/SourceKitD/sourcekitd_uids.swift

@@ -59,6 +59,7 @@ public struct sourcekitd_keys {
   public let request: sourcekitd_uid_t
   public let results: sourcekitd_uid_t
   public let retrieve_refactor_actions: sourcekitd_uid_t
+  public let semantic_tokens: sourcekitd_uid_t
   public let severity: sourcekitd_uid_t
   public let sourcefile: sourcekitd_uid_t
   public let sourcetext: sourcekitd_uid_t
@@ -135,6 +136,7 @@ public struct sourcekitd_keys {
     request = api.uid_get_from_cstr("key.request")!
     results = api.uid_get_from_cstr("key.results")!
     retrieve_refactor_actions = api.uid_get_from_cstr("key.retrieve_refactor_actions")!
+    semantic_tokens = api.uid_get_from_cstr("key.semantic_tokens")!
     severity = api.uid_get_from_cstr("key.severity")!
     sourcefile = api.uid_get_from_cstr("key.sourcefile")!
     sourcetext = api.uid_get_from_cstr("key.sourcetext")!

Sources/SourceKitLSP/Swift/SemanticTokens.swift

@@ -32,8 +32,14 @@ extension SwiftLanguageServer {
     skreq[keys.compilerargs] = buildSettings.compilerArgs
 
     let dict = try await sourcekitd.send(skreq)
-    print(dict.description)
-    return semanticTokens(of: dict, for: snapshot)
+
+    guard let skTokens: SKDResponseArray = dict[keys.semantic_tokens] else {
+      return nil
+    }
+    let tokenParser = SyntaxHighlightingTokenParser(sourcekitd: sourcekitd)
+    var tokens: [SyntaxHighlightingToken] = []
+    tokenParser.parseTokens(skTokens, in: snapshot, into: &tokens)
+    return tokens
   }
 
   /// Computes an array of syntax highlighting tokens from the syntax tree that

Sources/SourceKitLSP/Swift/SwiftLanguageServer.swift

@@ -192,21 +192,6 @@ public actor SwiftLanguageServer: ToolchainLanguageServer {
   ) {
     self.stateChangeHandlers.append(handler)
   }
-
-  /// Returns the semantic tokens in `response` for the given `snapshot`.
-  func semanticTokens(
-    of response: SKDResponseDictionary,
-    for snapshot: DocumentSnapshot
-  ) -> [SyntaxHighlightingToken]? {
-    guard let skTokens: SKDResponseArray = response[keys.annotations] else {
-      return nil
-    }
-    let tokenParser = SyntaxHighlightingTokenParser(sourcekitd: sourcekitd)
-    var tokens: [SyntaxHighlightingToken] = []
-    tokenParser.parseTokens(skTokens, in: snapshot, into: &tokens)
-
-    return tokens
-  }
 }
 
 extension SwiftLanguageServer {
@@ -343,6 +328,7 @@ extension SwiftLanguageServer {
     req[keys.request] = self.requests.editor_open
     req[keys.name] = note.textDocument.uri.pseudoPath
     req[keys.sourcetext] = snapshot.text
+    req[keys.syntactic_only] = 1
 
     let compileCommand = await self.buildSettings(for: snapshot.uri)
 
@@ -430,6 +416,7 @@ extension SwiftLanguageServer {
       let req = SKDRequestDictionary(sourcekitd: self.sourcekitd)
       req[keys.request] = self.requests.editor_replacetext
       req[keys.name] = note.textDocument.uri.pseudoPath
+      req[keys.syntactic_only] = 1
 
       if let range = edit.range {
         guard let offset = before.utf8OffsetOf(line: range.lowerBound.line, utf16Column: range.lowerBound.utf16index),