Use ServiceDescriptor within MethodDescriptor (#2127)

Motivation:

MethodDescriptor uses a string to represent the fully qualified name of
the service the method belongs to. ServiceDescriptor also represents a
fully qualified name of a service. It'd make more sense for
MethodDescriptor to use a ServiceDescriptor instead of a string to
describe the service.

Modifications:

- ServiceDescriptor now stores the fully qualified service name (as this
is generally more useful) and computes the package and unqualified
service name.
- ServiceDescriptor can now be created from the fully qualified name or
from a separate package and service name.
- MethodDescriptor now holds a ServiceDescriptor instead of a String for
the service

Result:

More coherent API

Author: glbrntt

Sources/GRPCCore/Call/Client/ClientInterceptorPipelineOperation.swift

@@ -61,7 +61,7 @@ public struct ClientInterceptorPipelineOperation: Sendable {
         return true
 
       case .services(let services):
-        return services.map({ $0.fullyQualifiedService }).contains(descriptor.service)
+        return services.contains(descriptor.service)
 
       case .methods(let methods):
         return methods.contains(descriptor)

Sources/GRPCCore/Call/Server/ServerInterceptorPipelineOperation.swift

@@ -61,7 +61,7 @@ public struct ServerInterceptorPipelineOperation: Sendable {
         return true
 
       case .services(let services):
-        return services.map({ $0.fullyQualifiedService }).contains(descriptor.service)
+        return services.contains(descriptor.service)
 
       case .methods(let methods):
         return methods.contains(descriptor)

Sources/GRPCCore/Internal/MethodConfigs.swift

@@ -51,7 +51,10 @@ package struct MethodConfigs: Sendable, Hashable {
   ///  - descriptor: The ``MethodDescriptor`` for which to get or set a ``MethodConfig``.
   package subscript(_ descriptor: MethodDescriptor) -> MethodConfig? {
     get {
-      var name = MethodConfig.Name(service: descriptor.service, method: descriptor.method)
+      var name = MethodConfig.Name(
+        service: descriptor.service.fullyQualifiedService,
+        method: descriptor.method
+      )
 
       if let configuration = self.elements[name] {
         return configuration
@@ -70,7 +73,10 @@ package struct MethodConfigs: Sendable, Hashable {
     }
 
     set {
-      let name = MethodConfig.Name(service: descriptor.service, method: descriptor.method)
+      let name = MethodConfig.Name(
+        service: descriptor.service.fullyQualifiedService,
+        method: descriptor.method
+      )
       self.elements[name] = newValue
     }
   }

Sources/GRPCCore/MethodDescriptor.swift

@@ -16,11 +16,8 @@
 
 /// A description of a method on a service.
 public struct MethodDescriptor: Sendable, Hashable {
-  /// The name of the service, including the package name.
-  ///
-  /// For example, the name of the "Greeter" service in "helloworld" package
-  /// is "helloworld.Greeter".
-  public var service: String
+  /// A description of the service, including its package name.
+  public var service: ServiceDescriptor
 
   /// The name of the method in the service, excluding the service name.
   public var method: String
@@ -39,8 +36,36 @@ public struct MethodDescriptor: Sendable, Hashable {
   ///   - service: The name of the service, including the package name. For example,
   ///       "helloworld.Greeter".
   ///   - method: The name of the method. For example, "SayHello".
-  public init(service: String, method: String) {
+  public init(service: ServiceDescriptor, method: String) {
     self.service = service
     self.method = method
   }
+
+  /// Creates a new method descriptor.
+  ///
+  /// - Parameters:
+  ///   - fullyQualifiedService: The fully qualified name of the service, including the package
+  ///       name. For example, "helloworld.Greeter".
+  ///   - method: The name of the method. For example, "SayHello".
+  public init(fullyQualifiedService: String, method: String) {
+    self.service = ServiceDescriptor(fullyQualifiedService: fullyQualifiedService)
+    self.method = method
+  }
+
+  @available(*, deprecated, renamed: "init(fullyQualifiedService:method:)")
+  /// Creates a new method descriptor.
+  ///
+  /// - Parameters:
+  ///   - service: The fully qualified name of the service, including the package
+  ///       name. For example, "helloworld.Greeter".
+  ///   - method: The name of the method. For example, "SayHello".
+  public init(service: String, method: String) {
+    self.init(fullyQualifiedService: service, method: method)
+  }
+}
+
+extension MethodDescriptor: CustomStringConvertible {
+  public var description: String {
+    self.fullyQualifiedMethod
+  }
 }

Sources/GRPCCore/ServiceDescriptor.swift

@@ -18,28 +18,50 @@
 public struct ServiceDescriptor: Sendable, Hashable {
   /// The name of the package the service belongs to. For example, "helloworld".
   /// An empty string means that the service does not belong to any package.
-  public var package: String
+  public var package: String {
+    if let index = self.fullyQualifiedService.utf8.lastIndex(of: UInt8(ascii: ".")) {
+      return String(self.fullyQualifiedService[..<index])
+    } else {
+      return ""
+    }
+  }
 
   /// The name of the service. For example, "Greeter".
-  public var service: String
+  public var service: String {
+    if var index = self.fullyQualifiedService.utf8.lastIndex(of: UInt8(ascii: ".")) {
+      self.fullyQualifiedService.utf8.formIndex(after: &index)
+      return String(self.fullyQualifiedService[index...])
+    } else {
+      return self.fullyQualifiedService
+    }
+  }
 
   /// The fully qualified service name in the format:
   /// - "package.service": if a package name is specified. For example, "helloworld.Greeter".
   /// - "service": if a package name is not specified. For example, "Greeter".
-  public var fullyQualifiedService: String {
-    if self.package.isEmpty {
-      return self.service
-    }
+  public var fullyQualifiedService: String
 
-    return "\(self.package).\(self.service)"
+  /// Create a new descriptor from the fully qualified service name.
+  /// - Parameter fullyQualifiedService: The fully qualified service name.
+  public init(fullyQualifiedService: String) {
+    self.fullyQualifiedService = fullyQualifiedService
   }
 
   /// - Parameters:
   ///   - package: The name of the package the service belongs to. For example, "helloworld".
   ///   An empty string means that the service does not belong to any package.
   ///   - service: The name of the service. For example, "Greeter".
   public init(package: String, service: String) {
-    self.package = package
-    self.service = service
+    if package.isEmpty {
+      self.fullyQualifiedService = service
+    } else {
+      self.fullyQualifiedService = package + "." + service
+    }
+  }
+}
+
+extension ServiceDescriptor: CustomStringConvertible {
+  public var description: String {
+    self.fullyQualifiedService
   }
 }

Tests/GRPCCoreTests/Call/Client/ClientInterceptorPipelineOperationTests.swift

@@ -61,8 +61,8 @@ struct ClientInterceptorPipelineOperationTests {
 }
 
 extension MethodDescriptor {
-  fileprivate static let fooBar = Self(service: "pkg.foo", method: "bar")
-  fileprivate static let fooBaz = Self(service: "pkg.foo", method: "baz")
-  fileprivate static let barFoo = Self(service: "pkg.bar", method: "foo")
-  fileprivate static let barBaz = Self(service: "pkg.bar", method: "Baz")
+  fileprivate static let fooBar = Self(fullyQualifiedService: "pkg.foo", method: "bar")
+  fileprivate static let fooBaz = Self(fullyQualifiedService: "pkg.foo", method: "baz")
+  fileprivate static let barFoo = Self(fullyQualifiedService: "pkg.bar", method: "foo")
+  fileprivate static let barBaz = Self(fullyQualifiedService: "pkg.bar", method: "Baz")
 }

Tests/GRPCCoreTests/Call/Client/Internal/ClientRPCExecutorTestSupport/ClientRPCExecutorTestHarness.swift

@@ -136,7 +136,7 @@ struct ClientRPCExecutorTestHarness {
       // Execute the request.
       try await ClientRPCExecutor.execute(
         request: request,
-        method: MethodDescriptor(service: "foo", method: "bar"),
+        method: MethodDescriptor(fullyQualifiedService: "foo", method: "bar"),
         options: options,
         serializer: serializer,
         deserializer: deserializer,

Tests/GRPCCoreTests/Call/Server/Internal/ServerRPCExecutorTestSupport/ServerRPCExecutorTestHarness.swift

@@ -101,7 +101,7 @@ struct ServerRPCExecutorTestHarness {
       group.addTask {
         await withServerContextRPCCancellationHandle { cancellation in
           let context = ServerContext(
-            descriptor: MethodDescriptor(service: "foo", method: "bar"),
+            descriptor: MethodDescriptor(fullyQualifiedService: "foo", method: "bar"),
             cancellation: cancellation
           )
 

Tests/GRPCCoreTests/Call/Server/RPCRouterTests.swift

@@ -22,13 +22,17 @@ final class RPCRouterTests: XCTestCase {
     var router = RPCRouter()
     XCTAssertEqual(router.count, 0)
     XCTAssertEqual(router.methods, [])
-    XCTAssertFalse(router.hasHandler(forMethod: MethodDescriptor(service: "foo", method: "bar")))
-    XCTAssertFalse(router.removeHandler(forMethod: MethodDescriptor(service: "foo", method: "bar")))
+    XCTAssertFalse(
+      router.hasHandler(forMethod: MethodDescriptor(fullyQualifiedService: "foo", method: "bar"))
+    )
+    XCTAssertFalse(
+      router.removeHandler(forMethod: MethodDescriptor(fullyQualifiedService: "foo", method: "bar"))
+    )
   }
 
   func testRegisterMethod() async throws {
     var router = RPCRouter()
-    let method = MethodDescriptor(service: "foo", method: "bar")
+    let method = MethodDescriptor(fullyQualifiedService: "foo", method: "bar")
     router.registerHandler(
       forMethod: method,
       deserializer: IdentityDeserializer(),
@@ -44,7 +48,7 @@ final class RPCRouterTests: XCTestCase {
 
   func testRemoveMethod() async throws {
     var router = RPCRouter()
-    let method = MethodDescriptor(service: "foo", method: "bar")
+    let method = MethodDescriptor(fullyQualifiedService: "foo", method: "bar")
     router.registerHandler(
       forMethod: method,
       deserializer: IdentityDeserializer(),

Tests/GRPCCoreTests/Call/Server/ServerInterceptorPipelineOperation.swift

@@ -61,8 +61,8 @@ struct ServerInterceptorPipelineOperationTests {
 }
 
 extension MethodDescriptor {
-  fileprivate static let fooBar = Self(service: "pkg.foo", method: "bar")
-  fileprivate static let fooBaz = Self(service: "pkg.foo", method: "baz")
-  fileprivate static let barFoo = Self(service: "pkg.bar", method: "foo")
-  fileprivate static let barBaz = Self(service: "pkg.bar", method: "Baz")
+  fileprivate static let fooBar = Self(fullyQualifiedService: "pkg.foo", method: "bar")
+  fileprivate static let fooBaz = Self(fullyQualifiedService: "pkg.foo", method: "baz")
+  fileprivate static let barFoo = Self(fullyQualifiedService: "pkg.bar", method: "foo")
+  fileprivate static let barBaz = Self(fullyQualifiedService: "pkg.bar", method: "Baz")
 }