feat: Add Swift-native codegen plugin

Package.swift

@@ -53,10 +53,12 @@ let package = Package(
         .library(name: "SmithyCBOR", targets: ["SmithyCBOR"]),
         .library(name: "SmithyWaitersAPI", targets: ["SmithyWaitersAPI"]),
         .library(name: "SmithyTestUtil", targets: ["SmithyTestUtil"]),
+        .plugin(name: "SmithyCodeGenerator", targets: ["SmithyCodeGenerator"]),
     ],
     dependencies: {
         var dependencies: [Package.Dependency] = [
             .package(url: "https://github.com/awslabs/aws-crt-swift.git", exact: "0.54.2"),
+            .package(url: "https://github.com/apple/swift-argument-parser.git", from: "1.0.0"),
             .package(url: "https://github.com/apple/swift-log.git", from: "1.0.0"),
             .package(url: "https://github.com/open-telemetry/opentelemetry-swift", from: "1.13.0"),
         ]
@@ -258,6 +260,23 @@ let package = Package(
         .target(
             name: "SmithyWaitersAPI"
         ),
+        .plugin(
+            name: "SmithyCodeGenerator",
+            capability: .buildTool(),
+            dependencies: [
+                "SmithyCodegenCLI",
+            ]
+        ),
+        .executableTarget(
+            name: "SmithyCodegenCLI",
+            dependencies: [
+                "SmithyCodegenCore",
+                .product(name: "ArgumentParser", package: "swift-argument-parser"),
+            ]
+        ),
+        .target(
+            name: "SmithyCodegenCore"
+        ),
         .testTarget(
             name: "ClientRuntimeTests",
             dependencies: [
@@ -268,6 +287,10 @@ let package = Package(
             ],
             resources: [ .process("Resources") ]
         ),
+        .testTarget(
+            name: "SmithyTests",
+            dependencies: ["Smithy"]
+        ),
         .testTarget(
             name: "SmithyCBORTests",
             dependencies: ["SmithyCBOR", "ClientRuntime", "SmithyTestUtil"]

Plugins/SmithyCodeGenerator/SmithyCodeGeneratorPlugin.swift

@@ -0,0 +1,66 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+import struct Foundation.Data
+import class Foundation.FileManager
+import class Foundation.JSONDecoder
+import struct Foundation.URL
+import PackagePlugin
+
+@main
+struct SmithyCodeGeneratorPlugin: BuildToolPlugin {
+
+    func createBuildCommands(context: PluginContext, target: Target) throws -> [Command] {
+        // This plugin only runs for package targets that can have source files.
+        guard let sourceFiles = target.sourceModule?.sourceFiles else { return [] }
+
+        // Retrieve the `SmithyCodegenCLI` tool from the plugin's tools.
+        let smithyCodegenCLITool = try context.tool(named: "SmithyCodegenCLI")
+
+        // Construct a build command for each source file with a particular suffix.
+        return try sourceFiles.map(\.path).compactMap {
+            try createBuildCommand(for: $0, in: context.pluginWorkDirectory, with: smithyCodegenCLITool.path)
+        }
+    }
+
+    private func createBuildCommand(
+        for inputPath: Path,
+        in outputDirectoryPath: Path,
+        with generatorToolPath: Path
+    ) throws -> Command? {
+        let currentWorkingDirectoryURL = URL(fileURLWithPath: FileManager.default.currentDirectoryPath)
+
+        // Skip any file that isn't the smithy-model-info.json for this service.
+        guard inputPath.lastComponent == "smithy-model-info.json" else { return nil }
+
+        // Get the smithy model path.
+        let modelInfoData = try Data(contentsOf: URL(fileURLWithPath: inputPath.string))
+        let smithyModelInfo = try JSONDecoder().decode(SmithyModelInfo.self, from: modelInfoData)
+        let modelPathURL = currentWorkingDirectoryURL.appendingPathComponent(smithyModelInfo.path)
+        let modelPath = Path(modelPathURL.path)
+
+        // Return a command that will run during the build to generate the output file.
+        let modelCountSwiftPath = outputDirectoryPath.appending("ModelCount.swift")
+        return .buildCommand(
+            displayName: "Generating Swift source files from \(smithyModelInfo.path)",
+            executable: generatorToolPath,
+            arguments: [modelPath, modelCountSwiftPath],
+            inputFiles: [inputPath, modelPath],
+            outputFiles: [modelCountSwiftPath]
+        )
+    }
+}
+
+/// Codable structure for reading the contents of `smithy-model-info.json`
+private struct SmithyModelInfo: Decodable {
+    /// The path to the model, from the root of the target's project.  Required.
+    let path: String
+}
+
+struct Err: Error {
+    var localizedDescription: String { "boom" }
+}

Sources/Smithy/Schema/Node.swift

@@ -0,0 +1,109 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+/// Contains the value of a Smithy Node.
+///
+/// Smithy node data is basically the same as the data that can be stored in JSON.
+/// The root of a Smithy node may be of any type, i.e. unlike JSON, the root element is not limited to object or list.
+///
+/// See the definition of node value in the Smithy spec: https://smithy.io/2.0/spec/model.html#node-values
+public enum Node: Sendable {
+    case object([String: Node])
+    case list([Node])
+    case string(String)
+    case number(Double)
+    case boolean(Bool)
+    case null
+}
+
+public extension Node {
+
+    /// Returns the object dictionary if this Node is `.object`, else returns `nil`.
+    var object: [String: Node]? {
+        guard case .object(let value) = self else { return nil }
+        return value
+    }
+
+    /// Returns the array of `Node` if this node is `.list`, else returns `nil`.
+    var list: [Node]? {
+        guard case .list(let value) = self else { return nil }
+        return value
+    }
+
+    /// Returns the string if this node is `.string`, else returns `nil`.
+    var string: String? {
+        guard case .string(let value) = self else { return nil }
+        return value
+    }
+
+    /// Returns the Double if this node is `.number`, else returns `nil`.
+    var number: Double? {
+        guard case .number(let value) = self else { return nil }
+        return value
+    }
+
+    /// Returns the `Bool` value if this node is `.boolean`, else returns `nil`.
+    var boolean: Bool? {
+        guard case .boolean(let value) = self else { return nil }
+        return value
+    }
+
+    /// Returns `true` if this node is `.null`, else returns `false`.
+    var null: Bool {
+        guard case .null = self else { return false }
+        return true
+    }
+}
+
+extension Node: ExpressibleByDictionaryLiteral {
+
+    public init(dictionaryLiteral elements: (String, Node)...) {
+        self = .object(Dictionary(uniqueKeysWithValues: elements))
+    }
+}
+
+extension Node: ExpressibleByArrayLiteral {
+
+    public init(arrayLiteral elements: Node...) {
+        self = .list(elements)
+    }
+}
+
+extension Node: ExpressibleByStringLiteral {
+
+    public init(stringLiteral value: String) {
+        self = .string(value)
+    }
+}
+
+extension Node: ExpressibleByIntegerLiteral {
+
+    public init(integerLiteral value: IntegerLiteralType) {
+        self = .number(Double(value))
+    }
+}
+
+extension Node: ExpressibleByFloatLiteral {
+
+    public init(floatLiteral value: FloatLiteralType) {
+        self = .number(Double(value))
+    }
+}
+
+extension Node: ExpressibleByBooleanLiteral {
+
+    public init(booleanLiteral value: BooleanLiteralType) {
+        self = .boolean(value)
+    }
+}
+
+extension Node: ExpressibleByNilLiteral {
+
+    public init(nilLiteral: ()) {
+        self = .null
+    }
+}

Sources/Smithy/Schema/Prelude.swift

@@ -0,0 +1,90 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+// Below are schemas for all model shapes defined in the Smithy 2.0 prelude.
+// Schemas for custom Smithy types may use these schemas in their definitions.
+
+public enum Prelude {
+
+    public static var unitSchema: Schema {
+        Schema(id: .init("smithy.api", "Unit"), type: .structure)
+    }
+
+    public static var booleanSchema: Schema {
+        Schema(id: .init("smithy.api", "Boolean"), type: .boolean)
+    }
+
+    public static var stringSchema: Schema {
+        Schema(id: .init("smithy.api", "String"), type: .string)
+    }
+
+    public static var integerSchema: Schema {
+        Schema(id: .init("smithy.api", "Integer"), type: .integer)
+    }
+
+    public static var blobSchema: Schema {
+        Schema(id: .init("smithy.api", "Blob"), type: .blob)
+    }
+
+    public static var timestampSchema: Schema {
+        Schema(id: .init("smithy.api", "Timestamp"), type: .timestamp)
+    }
+
+    public static var byteSchema: Schema {
+        Schema(id: .init("smithy.api", "Byte"), type: .byte)
+    }
+
+    public static var shortSchema: Schema {
+        Schema(id: .init("smithy.api", "Short"), type: .short)
+    }
+
+    public static var longSchema: Schema {
+        Schema(id: .init("smithy.api", "Long"), type: .long)
+    }
+
+    public static var floatSchema: Schema {
+        Schema(id: .init("smithy.api", "Float"), type: .float)
+    }
+
+    public static var doubleSchema: Schema {
+        Schema(id: .init("smithy.api", "Double"), type: .double)
+    }
+
+    public static var documentSchema: Schema {
+        Schema(id: .init("smithy.api", "PrimitiveDocument"), type: .document)
+    }
+
+    public static var primitiveBooleanSchema: Schema {
+        Schema(id: .init("smithy.api", "PrimitiveBoolean"), type: .boolean, traits: [defaultTraitID: false])
+    }
+
+    public static var primitiveIntegerSchema: Schema {
+        Schema(id: .init("smithy.api", "PrimitiveInteger"), type: .integer, traits: [defaultTraitID: 0])
+    }
+
+    public static var primitiveByteSchema: Schema {
+        Schema(id: .init("smithy.api", "PrimitiveByte"), type: .byte, traits: [defaultTraitID: 0])
+    }
+
+    public static var primitiveShortSchema: Schema {
+        Schema(id: .init("smithy.api", "PrimitiveShort"), type: .short, traits: [defaultTraitID: 0])
+    }
+
+    public static var primitiveLongSchema: Schema {
+        Schema(id: .init("smithy.api", "PrimitiveLong"), type: .long, traits: [defaultTraitID: 0])
+    }
+
+    public static var primitiveFloatSchema: Schema {
+        Schema(id: .init("smithy.api", "PrimitiveFloat"), type: .float, traits: [defaultTraitID: 0])
+    }
+
+    public static var primitiveDoubleSchema: Schema {
+        Schema(id: .init("smithy.api", "PrimitiveDouble"), type: .double, traits: [defaultTraitID: 0])
+    }
+}
+
+private let defaultTraitID = ShapeID("smithy.api", "default")

Sources/Smithy/Schema/Schema.swift

@@ -0,0 +1,72 @@
+//
+// Copyright Amazon.com Inc. or its affiliates.
+// All Rights Reserved.
+//
+// SPDX-License-Identifier: Apache-2.0
+//
+
+/// A class which describes selected Smithy model information for a Smithy model shape.
+///
+/// Typically, the Schema contains only modeled info & properties that are relevant to
+/// serialization, transport bindings, and other functions performed by the SDK.
+public final class Schema: Sendable {
+
+    /// The Smithy shape ID for the shape described by this schema.
+    public let id: ShapeID
+
+    /// The type of the shape being described.
+    public let type: ShapeType
+
+    /// A dictionary of the described shape's trait shape IDs to Nodes with trait data.
+    ///
+    /// Not all traits for a shape will be represented in the schema;
+    /// typically the Schema contains only the traits relevant to the client-side SDK.
+    public let traits: [ShapeID: Node]
+
+    /// The member schemas for this schema, if any.
+    ///
+    /// Typically only a schema of type Structure, Union, Enum, IntEnum, List or Map will have members.
+    public let members: [Schema]
+
+    /// The target schema for this schema.  Will only be used when this is a member schema.
+    public let target: Schema?
+
+    /// The index of this schema, if it represents a Smithy member.
+    ///
+    /// For a member schema, index will be set to its index in the members array.
+    /// For other types of schema, index will be `-1`.
+    ///
+    /// This index is intended for use as a performance enhancement when looking up member schemas
+    /// during deserialization.
+    public let index: Int
+
+    /// Creates a new Schema using the passed parameters.
+    ///
+    /// No validation is performed on the parameters since calls to this initializer
+    /// are almost always code-generated from a previously validated Smithy model.
+    public init(
+        id: ShapeID,
+        type: ShapeType,
+        traits: [ShapeID: Node] = [:],
+        members: [Schema] = [],
+        target: Schema? = nil,
+        index: Int = -1
+    ) {
+        self.id = id
+        self.type = type
+        self.traits = traits
+        self.members = members
+        self.target = target
+        self.index = index
+    }
+}
+
+public extension Schema {
+
+    /// The member name for this schema, if any.
+    ///
+    /// Member name is computed from the schema's ID.
+    var memberName: String? {
+        id.member
+    }
+}