add memory-management-mode config

Author: madsodgaard

Sources/JavaKitConfigurationShared/Configuration.swift

@@ -51,6 +51,11 @@ public struct Configuration: Codable {
     minimumInputAccessLevelMode ?? .default
   }
 
+  public var memoryManagementMode: JExtractMemoryManagementMode?
+  public var effectiveMemoryManagementMode: JExtractMemoryManagementMode {
+    memoryManagementMode ?? .forceExplicit
+  }
+
   // ==== java 2 swift ---------------------------------------------------------
 
   /// The Java class path that should be passed along to the swift-java tool.

Sources/JavaKitConfigurationShared/GenerationMode.swift

@@ -76,3 +76,18 @@ extension JExtractMinimumAccessLevelMode {
     .public
   }
 }
+
+
+/// Configures how memory should be managed by the user
+public enum JExtractMemoryManagementMode: String, Codable {
+  /// Force users to provide an explicit `SwiftArena` to all calls that require them.
+  case forceExplicit
+
+  /// Provide both explicit `SwiftArena` support
+  /// and a default global automatic `SwiftArena` that will deallocate memory when the GC decides to.
+  case allowAutomatic
+
+  /// Force all memory management to a default global automatic `SwiftArena`
+  /// that will deallocate memory when the GC decides to.
+  case forceAutomatic
+}

Sources/SwiftJavaTool/Commands/JExtractCommand.swift

@@ -67,6 +67,9 @@ extension SwiftJava {
     @Option(help: "The lowest access level of Swift declarations that should be extracted, defaults to 'public'.")
     var minimumInputAccessLevel: JExtractMinimumAccessLevelMode = .default
 
+    @Option(help: "The memory management mode to use for the generated code. By default, the user must explicitly provide `SwiftArena` to all calls that require it. By choosing `allow-automatic`, user can omit this parameter and a global GC-based arena will be used. `force-automatic` removes all explicit memory management.")
+    var memoryManagementMode: JExtractMemoryManagementMode = .forceExplicit
+
     @Option(
       help: """
             A swift-java configuration file for a given Swift module name on which this module depends,
@@ -89,6 +92,7 @@ extension SwiftJava.JExtractCommand {
     config.writeEmptyFiles = writeEmptyFiles
     config.unsignedNumbersMode = unsignedNumbers
     config.minimumInputAccessLevelMode = minimumInputAccessLevel
+    config.memoryManagementMode = memoryManagementMode
 
     try checkModeCompatibility()
 
@@ -117,6 +121,10 @@ extension SwiftJava.JExtractCommand {
       case .wrapGuava:
         () // OK
       }
+    } else if self.mode == .ffm {
+      guard self.memoryManagementMode == .forceExplicit else {
+        throw IllegalModeCombinationError("FFM mode does not support '\(self.memoryManagementMode)' memory management mode! \(Self.helpMessage)")
+      }
     }
   }
 }
@@ -148,3 +156,4 @@ struct IllegalModeCombinationError: Error {
 extension JExtractGenerationMode: ExpressibleByArgument {}
 extension JExtractUnsignedIntegerMode: ExpressibleByArgument {}
 extension JExtractMinimumAccessLevelMode: ExpressibleByArgument {}
+extension JExtractMemoryManagementMode: ExpressibleByArgument {}