String+JNIExtensions.swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2024 Apple Inc. and the Swift.org project authors
// Licensed under Apache License v2.0
//
// See LICENSE.txt for license information
// See CONTRIBUTORS.txt for the list of Swift.org project authors
//
// SPDX-License-Identifier: Apache-2.0
//
//===----------------------------------------------------------------------===//

import SwiftJavaJNICore

extension String {
  /// Returns a version of the string correctly escaped for a JNI identifier
  var escapedJNIIdentifier: String {
    self.map {
      if $0 == "_" {
        return "_1"
      } else if $0 == "/" {
        return "_"
      } else if $0 == ";" {
        return "_2"
      } else if $0 == "[" {
        return "_3"
      } else if $0.isASCII && ($0.isLetter || $0.isNumber) {
        return String($0)
      } else if let utf16 = $0.utf16.first {
        // Escape any non-alphanumeric to their UTF16 hex encoding
        let utf16Hex = String(format: "%04x", utf16)
        return "_0\(utf16Hex)"
      } else {
        fatalError("Invalid JNI character: \($0)")
      }
    }
    .joined()
  }

  /// Looks up self as a SwiftJava wrapped class name and converts it
  /// into a `JavaType.class` if it exists in `lookupTable`.
  func parseJavaClassFromSwiftJavaName(in lookupTable: [String: String]) -> JavaType? {
    guard let canonicalJavaName = lookupTable[self] else {
      return nil
    }
    let nameParts = canonicalJavaName.components(separatedBy: ".")
    let javaPackageName = nameParts.dropLast().joined(separator: ".")
    let javaClassName = nameParts.last!

    return .class(package: javaPackageName, name: javaClassName)
  }
}

extension Array where Element == String {
  func joinedJavaStatements(indent: Int) -> String {
    if self.count == 1 {
      return "\(self.first!);"
    }
    let indentation = String(repeating: " ", count: indent)
    return self.joined(separator: ";\n\(indentation)")
  }
}