Use SwiftProtobuf's new CodeGenerator interface (#2043)

Motivation:

SwiftProtobuf 1.27.0 added a new `CodeGenerator` interface in 1.27.0 and
deprecated the old API. This didn't include (non-deprecated) access to
the source proto which is required for reflection data, however, this
was added in 1.28.0.

Modification:

- Rename `options.swift` to `Options.swift`
- Rewrite `main` as `GenerateGRPC`, the functionality is unchanged but
did require a bit of code shuffling. As part of this some global methods
became private methods on the new `GenerateGRPC` `struct`.
- Add support for protobuf editions.

Result:

- Fewer warnings
- Can use protobuf editions

Package.swift

@@ -56,7 +56,7 @@ let packageDependencies: [Package.Dependency] = [
   ),
   .package(
     url: "https://github.com/apple/swift-protobuf.git",
-    from: "1.27.0"
+    from: "1.28.1"
   ),
   .package(
     url: "https://github.com/apple/swift-log.git",

Package@swift-6.swift

@@ -56,7 +56,7 @@ let packageDependencies: [Package.Dependency] = [
   ),
   .package(
     url: "https://github.com/apple/swift-protobuf.git",
-    from: "1.27.0"
+    from: "1.28.1"
   ),
   .package(
     url: "https://github.com/apple/swift-log.git",

Sources/protoc-gen-grpc-swift/GenerateGRPC.swift

@@ -0,0 +1,235 @@
+/*
+ * Copyright 2024, gRPC Authors All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+import Foundation
+import SwiftProtobuf
+import SwiftProtobufPluginLibrary
+
+#if compiler(>=6.0)
+import GRPCCodeGen
+import GRPCProtobufCodeGen
+#endif
+
+@main
+final class GenerateGRPC: CodeGenerator {
+  var version: String? {
+    Version.versionString
+  }
+
+  var projectURL: String {
+    "https://github.com/grpc/grpc-swift"
+  }
+
+  var supportedFeatures: [Google_Protobuf_Compiler_CodeGeneratorResponse.Feature] {
+    [.proto3Optional, .supportsEditions]
+  }
+
+  var supportedEditionRange: ClosedRange<Google_Protobuf_Edition> {
+    Google_Protobuf_Edition.proto2 ... Google_Protobuf_Edition.edition2023
+  }
+
+  // A count of generated files by desired name (actual name may differ to avoid collisions).
+  private var generatedFileNames: [String: Int] = [:]
+
+  func generate(
+    files fileDescriptors: [FileDescriptor],
+    parameter: any CodeGeneratorParameter,
+    protoCompilerContext: any ProtoCompilerContext,
+    generatorOutputs outputs: any GeneratorOutputs
+  ) throws {
+    let options = try GeneratorOptions(parameter: parameter)
+
+    for descriptor in fileDescriptors {
+      if options.generateReflectionData {
+        try self.generateReflectionData(
+          descriptor,
+          options: options,
+          outputs: outputs
+        )
+      }
+
+      if descriptor.services.isEmpty {
+        continue
+      }
+
+      if options.generateClient || options.generateServer || options.generateTestClient {
+        #if compiler(>=6.0)
+        if options.v2 {
+          try self.generateV2Stubs(descriptor, options: options, outputs: outputs)
+        } else {
+          try self.generateV1Stubs(descriptor, options: options, outputs: outputs)
+        }
+        #else
+        try self.generateV1Stubs(descriptor, options: options, outputs: outputs)
+        #endif
+      }
+    }
+  }
+
+  private func generateReflectionData(
+    _ descriptor: FileDescriptor,
+    options: GeneratorOptions,
+    outputs: any GeneratorOutputs
+  ) throws {
+    let fileName = self.uniqueOutputFileName(
+      fileDescriptor: descriptor,
+      fileNamingOption: options.fileNaming,
+      extension: "reflection"
+    )
+
+    var options = ExtractProtoOptions()
+    options.includeSourceCodeInfo = true
+    let proto = descriptor.extractProto(options: options)
+    let serializedProto = try proto.serializedData()
+    let reflectionData = serializedProto.base64EncodedString()
+    try outputs.add(fileName: fileName, contents: reflectionData)
+  }
+
+  private func generateV1Stubs(
+    _ descriptor: FileDescriptor,
+    options: GeneratorOptions,
+    outputs: any GeneratorOutputs
+  ) throws {
+    let fileName = self.uniqueOutputFileName(
+      fileDescriptor: descriptor,
+      fileNamingOption: options.fileNaming
+    )
+
+    let fileGenerator = Generator(descriptor, options: options)
+    try outputs.add(fileName: fileName, contents: fileGenerator.code)
+  }
+
+  #if compiler(>=6.0)
+  private func generateV2Stubs(
+    _ descriptor: FileDescriptor,
+    options: GeneratorOptions,
+    outputs: any GeneratorOutputs
+  ) throws {
+    let fileName = self.uniqueOutputFileName(
+      fileDescriptor: descriptor,
+      fileNamingOption: options.fileNaming
+    )
+
+    let config = SourceGenerator.Configuration(options: options)
+    let fileGenerator = ProtobufCodeGenerator(configuration: config)
+    let contents = try fileGenerator.generateCode(
+      from: descriptor,
+      protoFileModuleMappings: options.protoToModuleMappings,
+      extraModuleImports: options.extraModuleImports
+    )
+
+    try outputs.add(fileName: fileName, contents: contents)
+  }
+  #endif
+}
+
+extension GenerateGRPC {
+  private func uniqueOutputFileName(
+    fileDescriptor: FileDescriptor,
+    fileNamingOption: FileNaming,
+    component: String = "grpc",
+    extension: String = "swift"
+  ) -> String {
+    let defaultName = outputFileName(
+      component: component,
+      fileDescriptor: fileDescriptor,
+      fileNamingOption: fileNamingOption,
+      extension: `extension`
+    )
+    if let count = self.generatedFileNames[defaultName] {
+      self.generatedFileNames[defaultName] = count + 1
+      return outputFileName(
+        component: "\(count)." + component,
+        fileDescriptor: fileDescriptor,
+        fileNamingOption: fileNamingOption,
+        extension: `extension`
+      )
+    } else {
+      self.generatedFileNames[defaultName] = 1
+      return defaultName
+    }
+  }
+
+  private func outputFileName(
+    component: String,
+    fileDescriptor: FileDescriptor,
+    fileNamingOption: FileNaming,
+    extension: String
+  ) -> String {
+    let ext = "." + component + "." + `extension`
+    let pathParts = splitPath(pathname: fileDescriptor.name)
+    switch fileNamingOption {
+    case .fullPath:
+      return pathParts.dir + pathParts.base + ext
+    case .pathToUnderscores:
+      let dirWithUnderscores =
+        pathParts.dir.replacingOccurrences(of: "/", with: "_")
+      return dirWithUnderscores + pathParts.base + ext
+    case .dropPath:
+      return pathParts.base + ext
+    }
+  }
+}
+
+// from apple/swift-protobuf/Sources/protoc-gen-swift/StringUtils.swift
+private func splitPath(pathname: String) -> (dir: String, base: String, suffix: String) {
+  var dir = ""
+  var base = ""
+  var suffix = ""
+
+  for character in pathname {
+    if character == "/" {
+      dir += base + suffix + String(character)
+      base = ""
+      suffix = ""
+    } else if character == "." {
+      base += suffix
+      suffix = String(character)
+    } else {
+      suffix += String(character)
+    }
+  }
+
+  let validSuffix = suffix.isEmpty || suffix.first == "."
+  if !validSuffix {
+    base += suffix
+    suffix = ""
+  }
+  return (dir: dir, base: base, suffix: suffix)
+}
+
+#if compiler(>=6.0)
+extension SourceGenerator.Configuration {
+  init(options: GeneratorOptions) {
+    let accessLevel: SourceGenerator.Configuration.AccessLevel
+    switch options.visibility {
+    case .internal:
+      accessLevel = .internal
+    case .package:
+      accessLevel = .package
+    case .public:
+      accessLevel = .public
+    }
+
+    self.init(
+      accessLevel: accessLevel,
+      accessLevelOnImports: options.useAccessLevelOnImports,
+      client: options.generateClient,
+      server: options.generateServer
+    )
+  }
+}
+#endif

Sources/protoc-gen-grpc-swift/options.swift → Sources/protoc-gen-grpc-swift/Options.swift

@@ -36,7 +36,13 @@ enum GenerationError: Error {
   }
 }
 
-final class GeneratorOptions {
+enum FileNaming: String {
+  case fullPath = "FullPath"
+  case pathToUnderscores = "PathToUnderscores"
+  case dropPath = "DropPath"
+}
+
+struct GeneratorOptions {
   enum Visibility: String {
     case `internal` = "Internal"
     case `public` = "Public"
@@ -63,7 +69,7 @@ final class GeneratorOptions {
 
   private(set) var keepMethodCasing = false
   private(set) var protoToModuleMappings = ProtoFileToModuleMappings()
-  private(set) var fileNaming = FileNaming.FullPath
+  private(set) var fileNaming = FileNaming.fullPath
   private(set) var extraModuleImports: [String] = []
   private(set) var gRPCModuleName = "GRPC"
   private(set) var swiftProtobufModuleName = "SwiftProtobuf"
@@ -73,8 +79,12 @@ final class GeneratorOptions {
   #endif
   private(set) var useAccessLevelOnImports = true
 
-  init(parameter: String?) throws {
-    for pair in GeneratorOptions.parseParameter(string: parameter) {
+  init(parameter: any CodeGeneratorParameter) throws {
+    try self.init(pairs: parameter.parsedPairs)
+  }
+
+  init(pairs: [(key: String, value: String)]) throws {
+    for pair in pairs {
       switch pair.key {
       case "Visibility":
         if let value = Visibility(rawValue: pair.value) {

Sources/protoc-gen-grpc-swift/main.swift

@@ -1,230 +0,0 @@
-/*
- * Copyright 2017, gRPC Authors All rights reserved.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *     http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-import Foundation
-import SwiftProtobuf
-import SwiftProtobufPluginLibrary
-
-#if compiler(>=6.0)
-import GRPCCodeGen
-import GRPCProtobufCodeGen
-#endif
-
-func Log(_ message: String) {
-  FileHandle.standardError.write((message + "\n").data(using: .utf8)!)
-}
-
-// from apple/swift-protobuf/Sources/protoc-gen-swift/StringUtils.swift
-func splitPath(pathname: String) -> (dir: String, base: String, suffix: String) {
-  var dir = ""
-  var base = ""
-  var suffix = ""
-  #if swift(>=3.2)
-  let pathnameChars = pathname
-  #else
-  let pathnameChars = pathname.characters
-  #endif
-  for c in pathnameChars {
-    if c == "/" {
-      dir += base + suffix + String(c)
-      base = ""
-      suffix = ""
-    } else if c == "." {
-      base += suffix
-      suffix = String(c)
-    } else {
-      suffix += String(c)
-    }
-  }
-  #if swift(>=3.2)
-  let validSuffix = suffix.isEmpty || suffix.first == "."
-  #else
-  let validSuffix = suffix.isEmpty || suffix.characters.first == "."
-  #endif
-  if !validSuffix {
-    base += suffix
-    suffix = ""
-  }
-  return (dir: dir, base: base, suffix: suffix)
-}
-
-enum FileNaming: String {
-  case FullPath
-  case PathToUnderscores
-  case DropPath
-}
-
-func outputFileName(
-  component: String,
-  fileDescriptor: FileDescriptor,
-  fileNamingOption: FileNaming,
-  extension: String
-) -> String {
-  let ext = "." + component + "." + `extension`
-  let pathParts = splitPath(pathname: fileDescriptor.name)
-  switch fileNamingOption {
-  case .FullPath:
-    return pathParts.dir + pathParts.base + ext
-  case .PathToUnderscores:
-    let dirWithUnderscores =
-      pathParts.dir.replacingOccurrences(of: "/", with: "_")
-    return dirWithUnderscores + pathParts.base + ext
-  case .DropPath:
-    return pathParts.base + ext
-  }
-}
-
-func uniqueOutputFileName(
-  component: String,
-  fileDescriptor: FileDescriptor,
-  fileNamingOption: FileNaming,
-  generatedFiles: inout [String: Int],
-  extension: String = "swift"
-) -> String {
-  let defaultName = outputFileName(
-    component: component,
-    fileDescriptor: fileDescriptor,
-    fileNamingOption: fileNamingOption,
-    extension: `extension`
-  )
-  if let count = generatedFiles[defaultName] {
-    generatedFiles[defaultName] = count + 1
-    return outputFileName(
-      component: "\(count)." + component,
-      fileDescriptor: fileDescriptor,
-      fileNamingOption: fileNamingOption,
-      extension: `extension`
-    )
-  } else {
-    generatedFiles[defaultName] = 1
-    return defaultName
-  }
-}
-
-func printVersion(args: [String]) {
-  // Stip off the file path
-  let program = args.first?.split(separator: "/").last ?? "protoc-gen-grpc-swift"
-  print("\(program) \(Version.versionString)")
-}
-
-func main(args: [String]) throws {
-  if args.dropFirst().contains("--version") {
-    printVersion(args: args)
-    return
-  }
-
-  // initialize responses
-  var response = Google_Protobuf_Compiler_CodeGeneratorResponse(
-    files: [],
-    supportedFeatures: [.proto3Optional]
-  )
-
-  // read plugin input
-  let rawRequest = FileHandle.standardInput.readDataToEndOfFile()
-  let request = try Google_Protobuf_Compiler_CodeGeneratorRequest(serializedData: rawRequest)
-
-  let options = try GeneratorOptions(parameter: request.parameter)
-
-  // Build the SwiftProtobufPluginLibrary model of the plugin input
-  let descriptorSet = DescriptorSet(protos: request.protoFile)
-
-  // A count of generated files by desired name (actual name may differ to avoid collisions).
-  var generatedFiles: [String: Int] = [:]
-
-  // Only generate output for services.
-  for name in request.fileToGenerate {
-    if let fileDescriptor = descriptorSet.fileDescriptor(named: name) {
-      if options.generateReflectionData {
-        var binaryFile = Google_Protobuf_Compiler_CodeGeneratorResponse.File()
-        let binaryFileName = uniqueOutputFileName(
-          component: "grpc",
-          fileDescriptor: fileDescriptor,
-          fileNamingOption: options.fileNaming,
-          generatedFiles: &generatedFiles,
-          extension: "reflection"
-        )
-        let serializedFileDescriptorProto = try fileDescriptor.proto.serializedData()
-          .base64EncodedString()
-        binaryFile.name = binaryFileName
-        binaryFile.content = serializedFileDescriptorProto
-        response.file.append(binaryFile)
-      }
-      if !fileDescriptor.services.isEmpty
-        && (options.generateClient || options.generateServer || options.generateTestClient)
-      {
-        var grpcFile = Google_Protobuf_Compiler_CodeGeneratorResponse.File()
-        let grpcFileName = uniqueOutputFileName(
-          component: "grpc",
-          fileDescriptor: fileDescriptor,
-          fileNamingOption: options.fileNaming,
-          generatedFiles: &generatedFiles
-        )
-
-        #if compiler(>=6.0)
-        if options.v2 {
-          let grpcGenerator = ProtobufCodeGenerator(
-            configuration: SourceGenerator.Configuration(options: options)
-          )
-          grpcFile.content = try grpcGenerator.generateCode(
-            from: fileDescriptor,
-            protoFileModuleMappings: options.protoToModuleMappings,
-            extraModuleImports: options.extraModuleImports
-          )
-        } else {
-          let grpcGenerator = Generator(fileDescriptor, options: options)
-          grpcFile.content = grpcGenerator.code
-        }
-        #else
-        let grpcGenerator = Generator(fileDescriptor, options: options)
-        grpcFile.content = grpcGenerator.code
-        #endif
-        grpcFile.name = grpcFileName
-        response.file.append(grpcFile)
-      }
-    }
-  }
-
-  // return everything to the caller
-  let serializedResponse = try response.serializedData()
-  FileHandle.standardOutput.write(serializedResponse)
-}
-
-do {
-  try main(args: CommandLine.arguments)
-} catch {
-  Log("ERROR: \(error)")
-}
-
-#if compiler(>=6.0)
-extension SourceGenerator.Configuration {
-  init(options: GeneratorOptions) {
-    let accessLevel: SourceGenerator.Configuration.AccessLevel
-    switch options.visibility {
-    case .internal:
-      accessLevel = .internal
-    case .package:
-      accessLevel = .package
-    case .public:
-      accessLevel = .public
-    }
-    self.init(
-      accessLevel: accessLevel,
-      accessLevelOnImports: options.useAccessLevelOnImports,
-      client: options.generateClient,
-      server: options.generateServer
-    )
-  }
-}
-#endif