Document/Clean up Descriptors.

- Add docs for just about everything (based on C++ Descriptors).
- Tweak some method naming based on C++ Descriptors.
- Add some apis that are on the C++ Descriptors.
- Reduce how much of the raw protos are kept in memory.

Author: thomasvl

Sources/SwiftProtobufPluginLibrary/Descriptor+Extensions.swift

@@ -85,12 +85,6 @@ extension FieldDescriptor: ProvidesLocationPath, ProvidesSourceCodeLocation {
     }
   }
 
-  /// Is this field packable.
-  var isPackable: Bool {
-    // This logic comes from the C++ FieldDescriptor::is_packable() impl.
-    return label == .repeated && FieldDescriptor.isPackable(type: type)
-  }
-
   /// Helper to return the name to as the "base" for naming of generated fields.
   ///
   /// Groups use the underlying message's name. The way groups are declared in

Sources/SwiftProtobufPluginLibrary/Descriptor.swift

@@ -10,7 +10,13 @@
 
 import Foundation
 
+/// Protocol that all the Descriptors conform to for original .proto file
+/// location lookup.
 public protocol ProvidesLocationPath {
+  /// Updates `path` to the source location of the complete extent of
+  /// the object conforming to this protocol. This is a replacement for
+  /// `GetSourceLocation()` in the C++ Descriptor apis.
   func getLocationPath(path: inout IndexPath)
+  /// Returns the File this conforming object is in.
   var file: FileDescriptor! { get }
 }

Sources/SwiftProtobufPluginLibrary/ProvidesLocationPath.swift

@@ -11,11 +11,14 @@
 import Foundation
 import SwiftProtobuf
 
+/// Protocol that all the Descriptors conform to for original .proto file
+/// location lookup.
 public protocol ProvidesSourceCodeLocation {
+  /// Returns the Location of a given object (Descriptor).
   var sourceCodeInfoLocation: Google_Protobuf_SourceCodeInfo.Location? { get }
 }
 
-// Default implementation for things that support ProvidesLocationPath.
+/// Default implementation for things that support ProvidesLocationPath.
 extension ProvidesSourceCodeLocation where Self: ProvidesLocationPath {
   public var sourceCodeInfoLocation: Google_Protobuf_SourceCodeInfo.Location? {
     var path = IndexPath()
@@ -24,14 +27,12 @@ extension ProvidesSourceCodeLocation where Self: ProvidesLocationPath {
   }
 }
 
-// Helper to get source comments out of ProvidesSourceCodeLocation
 extension ProvidesSourceCodeLocation {
+  /// Helper to get a source comments as a string.
   public func protoSourceComments(commentPrefix: String = "///",
                                   leadingDetachedPrefix: String? = nil) -> String {
-    if let loc = sourceCodeInfoLocation {
-      return loc.asSourceComment(commentPrefix: commentPrefix,
-                                 leadingDetachedPrefix: leadingDetachedPrefix)
-    }
-    return String()
+    guard let loc = sourceCodeInfoLocation else { return String() }
+    return loc.asSourceComment(commentPrefix: commentPrefix,
+                               leadingDetachedPrefix: leadingDetachedPrefix)
   }
 }

Sources/SwiftProtobufPluginLibrary/ProvidesSourceCodeLocation.swift

@@ -15,7 +15,7 @@
 import Foundation
 import SwiftProtobuf
 
-/// Scope for helpers about the library.
+/// Helpers about the library.
 public enum SwiftProtobufInfo {
   /// Proto Files that ship with the library.
   public static let bundledProtoFiles: Set<String> = [
@@ -35,8 +35,14 @@ public enum SwiftProtobufInfo {
     "google/protobuf/wrappers.proto",
   ]
 
-  // Checks if a FileDescriptor is a library bundled proto file.
+  /// Checks if a `Google_Protobuf_FileDescriptorProto` is a library bundled proto file.
+  @available(*, deprecated, message: "Use the version that takes a FileDescriptor instead.")
   public static func isBundledProto(file: Google_Protobuf_FileDescriptorProto) -> Bool {
     return file.package == "google.protobuf" && bundledProtoFiles.contains(file.name)
   }
+
+  /// Checks if a `FileDescriptor` is a library bundled proto file.
+  public static func isBundledProto(file: FileDescriptor) -> Bool {
+    return file.package == "google.protobuf" && bundledProtoFiles.contains(file.name)
+  }
 }

Sources/SwiftProtobufPluginLibrary/SwiftProtobufInfo.swift

@@ -332,7 +332,7 @@ public final class SwiftProtobufNamer {
     }
 
     let result = NamingUtils.typePrefix(protoPackage: file.package,
-                                        fileOptions: file.fileOptions)
+                                        fileOptions: file.options)
     filePrefixCache[file.name] = result
     return result
   }

Sources/SwiftProtobufPluginLibrary/SwiftProtobufNamer.swift

@@ -17,17 +17,13 @@ extension FileDescriptor {
   }
 
   var isBundledProto: Bool {
-    return SwiftProtobufInfo.isBundledProto(file: proto)
+    return SwiftProtobufInfo.isBundledProto(file: self)
   }
 }
 
 extension Descriptor {
-  /// Returns True if this is the Any WKT
-  var isAnyMessage: Bool {
-    return (file.syntax == .proto3 &&
-      fullName == ".google.protobuf.Any" &&
-      file.name == "google/protobuf/any.proto")
-  }
+  /// Returns true if the message should use the message set wireformat.
+  var useMessageSetWireFormat: Bool { return options.messageSetWireFormat }
 
   /// Returns True if this message recurisvely contains a required field.
   /// This is a helper for generating isInitialized methods.
@@ -54,7 +50,7 @@ extension Descriptor {
       }
 
       for f in descriptor.fields {
-        if f.label == .required {
+        if f.isRequired {
           return true
         }
         switch f.type {
@@ -138,7 +134,7 @@ extension FieldDescriptor {
     case .repeated:
       return swiftType
     case .optional, .required:
-      guard realOneof == nil else {
+      guard realContainingOneof == nil else {
         return swiftType
       }
       if hasPresence {
@@ -217,7 +213,7 @@ extension FieldDescriptor {
     case .group, .message:
       return namer.fullName(message: messageType) + "()"
     case .enum:
-      return namer.dottedRelativeName(enumValue: enumType.defaultValue)
+      return namer.dottedRelativeName(enumValue: enumType.values.first!)
     default:
       return "0"
     }

Sources/protoc-gen-swift/Descriptor+Extensions.swift

@@ -69,7 +69,7 @@ class EnumGenerator {
     p.print("\n")
     p.print("\(visibility)init() {\n")
     p.indent()
-    let dottedDefault = namer.dottedRelativeName(enumValue: enumDescriptor.defaultValue)
+    let dottedDefault = namer.dottedRelativeName(enumValue: enumDescriptor.values.first!)
     p.print("self = \(dottedDefault)\n")
     p.outdent()
     p.print("}\n")

Sources/protoc-gen-swift/EnumGenerator.swift

@@ -50,10 +50,10 @@ class FileGenerator {
     /// Generate, if `errorString` gets filled in, then report error instead of using
     /// what written into `printer`.
     func generateOutputFile(printer p: inout CodePrinter, errorString: inout String?) {
-        guard fileDescriptor.fileOptions.swiftPrefix.isEmpty ||
-            isValidSwiftIdentifier(fileDescriptor.fileOptions.swiftPrefix,
+        guard fileDescriptor.options.swiftPrefix.isEmpty ||
+            isValidSwiftIdentifier(fileDescriptor.options.swiftPrefix,
                                    allowQuoted: false) else {
-          errorString = "\(fileDescriptor.name) has an 'swift_prefix' that isn't a valid Swift identifier (\(fileDescriptor.fileOptions.swiftPrefix))."
+          errorString = "\(fileDescriptor.name) has an 'swift_prefix' that isn't a valid Swift identifier (\(fileDescriptor.options.swiftPrefix))."
           return
         }
         p.print(

Sources/protoc-gen-swift/FileGenerator.swift

@@ -38,7 +38,7 @@ class MessageFieldGenerator: FieldGeneratorBase, FieldGenerator {
     private var isPacked: Bool { return fieldDescriptor.isPacked }
 
     // Note: this could still be a map (since those are repeated message fields
-    private var isRepeated: Bool {return fieldDescriptor.label == .repeated}
+    private var isRepeated: Bool {return fieldDescriptor.isRepeated}
     private var isGroupOrMessage: Bool {
       switch fieldDescriptor.type {
       case .group, .message:
@@ -53,13 +53,13 @@ class MessageFieldGenerator: FieldGeneratorBase, FieldGenerator {
          namer: SwiftProtobufNamer,
          usesHeapStorage: Bool)
     {
-        precondition(descriptor.realOneof == nil)
+        precondition(descriptor.realContainingOneof == nil)
 
         self.generatorOptions = generatorOptions
         self.usesHeapStorage = usesHeapStorage
         self.namer = namer
 
-        hasFieldPresence = descriptor.hasPresence && descriptor.realOneof == nil
+        hasFieldPresence = descriptor.hasPresence
         let names = namer.messagePropertyNames(field: descriptor,
                                                prefixed: "_",
                                                includeHasAndClear: hasFieldPresence)
@@ -155,7 +155,7 @@ class MessageFieldGenerator: FieldGeneratorBase, FieldGenerator {
     }
 
    func generateRequiredFieldCheck(printer p: inout CodePrinter) {
-       guard fieldDescriptor.label == .required else { return }
+       guard fieldDescriptor.isRequired else { return }
        p.print("if \(storedProperty) == nil {return false}\n")
     }