Merge pull request #2643 from rintaro/6.0-macros-library-provider

[6.0] Macro plugin related changes

Author: rintaro

Package.swift

@@ -139,6 +139,14 @@ let package = Package(
       dependencies: ["_SwiftSyntaxTestSupport", "SwiftIDEUtils", "SwiftParser", "SwiftSyntax"]
     ),
 
+    // MARK: SwiftLibraryPluginProvider
+
+    .target(
+      name: "SwiftLibraryPluginProvider",
+      dependencies: ["SwiftSyntaxMacros", "SwiftCompilerPluginMessageHandling"],
+      exclude: ["CMakeLists.txt"]
+    ),
+
     // MARK: SwiftSyntax
 
     .target(

Sources/CMakeLists.txt

@@ -10,6 +10,7 @@ add_subdirectory(_SwiftSyntaxCShims)
 add_subdirectory(SwiftBasicFormat)
 add_subdirectory(SwiftSyntax)
 add_subdirectory(SwiftDiagnostics)
+add_subdirectory(SwiftLibraryPluginProvider)
 add_subdirectory(SwiftParser)
 add_subdirectory(SwiftParserDiagnostics)
 add_subdirectory(SwiftRefactor)

Sources/SwiftCompilerPlugin/CompilerPlugin.swift

@@ -111,13 +111,7 @@ extension CompilerPlugin {
   public static func main() throws {
     let connection = try StandardIOMessageConnection()
     let provider = MacroProviderAdapter(plugin: Self())
-    let impl = CompilerPluginMessageHandler(connection: connection, provider: provider)
-    do {
-      try impl.main()
-    } catch {
-      // Emit a diagnostic and indicate failure to the plugin host,
-      // and exit with an error code.
-      fatalError("Internal Error: \(error)")
-    }
+    let impl = CompilerPluginMessageListener(connection: connection, provider: provider)
+    impl.main()
   }
 }

Sources/SwiftCompilerPluginMessageHandling/CompilerPluginMessageHandler.swift

@@ -11,8 +11,10 @@
 //===----------------------------------------------------------------------===//
 
 #if swift(>=6)
+private import _SwiftSyntaxCShims
 public import SwiftSyntaxMacros
 #else
+@_implementationOnly import _SwiftSyntaxCShims
 import SwiftSyntaxMacros
 #endif
 
@@ -23,6 +25,8 @@ public enum PluginFeature: String {
 }
 
 /// A type that provides the actual plugin functions.
+///
+/// Note that it's an implementation's responsibility to cache the API results as needed.
 @_spi(PluginMessage)
 public protocol PluginProvider {
   /// Resolve macro type by the module name and the type name.
@@ -64,50 +68,60 @@ struct HostCapability {
   var hasExpandMacroResult: Bool { protocolVersion >= 5 }
 }
 
-/// 'CompilerPluginMessageHandler' is a type that listens to the message
-/// connection and dispatches them to the actual plugin provider, then send back
+/// 'CompilerPluginMessageListener' is a type that listens to the message
+/// connection, delegate them to the message handler, then send back
 /// the response.
 ///
 /// The low level connection and the provider is injected by the client.
 @_spi(PluginMessage)
-public class CompilerPluginMessageHandler<Connection: MessageConnection, Provider: PluginProvider> {
+public class CompilerPluginMessageListener<Connection: MessageConnection, Provider: PluginProvider> {
   /// Message channel for bidirectional communication with the plugin host.
   let connection: Connection
 
-  /// Object to provide actual plugin functions.
-  let provider: Provider
-
-  /// Plugin host capability
-  var hostCapability: HostCapability
+  let handler: CompilerPluginMessageHandler<Provider>
 
   public init(connection: Connection, provider: Provider) {
     self.connection = connection
-    self.provider = provider
-    self.hostCapability = HostCapability()
-  }
-}
-
-extension CompilerPluginMessageHandler {
-  func sendMessage(_ message: PluginToHostMessage) throws {
-    try connection.sendMessage(message)
-  }
-
-  func waitForNextMessage() throws -> HostToPluginMessage? {
-    try connection.waitForNextMessage(HostToPluginMessage.self)
+    self.handler = CompilerPluginMessageHandler(provider: provider)
   }
 
   /// Run the main message listener loop.
   /// Returns when the message connection was closed.
-  /// Throws an error when it failed to send/receive the message, or failed
-  /// to serialize/deserialize the message.
-  public func main() throws {
-    while let message = try self.waitForNextMessage() {
-      try handleMessage(message)
+  ///
+  /// On internal errors, such as I/O errors or JSON serialization errors, print
+  /// an error message and `exit(1)`
+  public func main() {
+    do {
+      while let message = try connection.waitForNextMessage(HostToPluginMessage.self) {
+        let result = handler.handleMessage(message)
+        try connection.sendMessage(result)
+      }
+    } catch {
+      // Emit a diagnostic and indicate failure to the plugin host,
+      // and exit with an error code.
+      fputs("Internal Error: \(error)\n", _stderr)
+      exit(1)
     }
   }
+}
+
+/// 'CompilerPluginMessageHandler' is a type that handle a message and do the
+/// corresponding operation.
+@_spi(PluginMessage)
+public class CompilerPluginMessageHandler<Provider: PluginProvider> {
+  /// Object to provide actual plugin functions.
+  let provider: Provider
+
+  /// Plugin host capability
+  var hostCapability: HostCapability
+
+  public init(provider: Provider) {
+    self.provider = provider
+    self.hostCapability = HostCapability()
+  }
 
   /// Handles a single message received from the plugin host.
-  fileprivate func handleMessage(_ message: HostToPluginMessage) throws {
+  public func handleMessage(_ message: HostToPluginMessage) -> PluginToHostMessage {
     switch message {
     case .getCapability(let hostCapability):
       // Remember the peer capability if provided.
@@ -120,7 +134,7 @@ extension CompilerPluginMessageHandler {
         protocolVersion: PluginMessage.PROTOCOL_VERSION_NUMBER,
         features: provider.features.map({ $0.rawValue })
       )
-      try self.sendMessage(.getCapabilityResult(capability: capability))
+      return .getCapabilityResult(capability: capability)
 
     case .expandFreestandingMacro(
       let macro,
@@ -129,7 +143,7 @@ extension CompilerPluginMessageHandler {
       let expandingSyntax,
       let lexicalContext
     ):
-      try expandFreestandingMacro(
+      return expandFreestandingMacro(
         macro: macro,
         macroRole: macroRole,
         discriminator: discriminator,
@@ -148,7 +162,7 @@ extension CompilerPluginMessageHandler {
       let conformanceListSyntax,
       let lexicalContext
     ):
-      try expandAttachedMacro(
+      return expandAttachedMacro(
         macro: macro,
         macroRole: macroRole,
         discriminator: discriminator,
@@ -176,7 +190,7 @@ extension CompilerPluginMessageHandler {
           )
         )
       }
-      try self.sendMessage(.loadPluginLibraryResult(loaded: diags.isEmpty, diagnostics: diags));
+      return .loadPluginLibraryResult(loaded: diags.isEmpty, diagnostics: diags)
     }
   }
 }

Sources/SwiftCompilerPluginMessageHandling/Macros.swift

@@ -55,7 +55,7 @@ extension CompilerPluginMessageHandler {
     discriminator: String,
     expandingSyntax: PluginMessage.Syntax,
     lexicalContext: [PluginMessage.Syntax]?
-  ) throws {
+  ) -> PluginToHostMessage {
     let sourceManager = SourceManager()
     let syntax = sourceManager.add(expandingSyntax, foldingWith: .standardOperators)
 
@@ -105,7 +105,7 @@ extension CompilerPluginMessageHandler {
       // TODO: Remove this  when all compilers have 'hasExpandMacroResult'.
       response = .expandFreestandingMacroResult(expandedSource: expandedSource, diagnostics: diagnostics)
     }
-    try self.sendMessage(response)
+    return response
   }
 
   /// Expand `@attached(XXX)` macros.
@@ -119,7 +119,7 @@ extension CompilerPluginMessageHandler {
     extendedTypeSyntax: PluginMessage.Syntax?,
     conformanceListSyntax: PluginMessage.Syntax?,
     lexicalContext: [PluginMessage.Syntax]?
-  ) throws {
+  ) -> PluginToHostMessage {
     let sourceManager = SourceManager()
     let attributeNode = sourceManager.add(
       attributeSyntax,
@@ -189,7 +189,7 @@ extension CompilerPluginMessageHandler {
     } else {
       response = .expandAttachedMacroResult(expandedSources: expandedSources, diagnostics: diagnostics)
     }
-    try self.sendMessage(response)
+    return response
   }
 }
 

Sources/SwiftLibraryPluginProvider/CMakeLists.txt

@@ -0,0 +1,16 @@
+# This source file is part of the Swift.org open source project
+#
+# Copyright (c) 2024 Apple Inc. and the Swift project authors
+# Licensed under Apache License v2.0 with Runtime Library Exception
+#
+# See http://swift.org/LICENSE.txt for license information
+# See http://swift.org/CONTRIBUTORS.txt for Swift project authors
+
+add_swift_syntax_library(SwiftLibraryPluginProvider
+  LibraryPluginProvider.swift
+)
+
+target_link_swift_syntax_libraries(SwiftLibraryPluginProvider PUBLIC
+  SwiftSyntaxMacros
+  SwiftCompilerPluginMessageHandling
+)