_AttachableURLContainer.swift

//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2024 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See https://swift.org/LICENSE.txt for license information
// See https://swift.org/CONTRIBUTORS.txt for Swift project authors
//

#if !SWT_NO_FOUNDATION && canImport(Foundation)
@_spi(Experimental) public import Testing
public import Foundation

/// A wrapper type representing file system objects and URLs that can be
/// attached indirectly.
///
/// You do not need to use this type directly. Instead, initialize an instance
/// of ``Attachment`` using a file URL.
@_spi(Experimental)
public struct _AttachableURLContainer: Sendable {
  /// The underlying URL.
  var url: URL

  /// The data contained at ``url``.
  var data: Data

  /// Whether or not this instance represents a compressed directory.
  var isCompressedDirectory: Bool
}

// MARK: -

extension _AttachableURLContainer: AttachableContainer {
  public var attachableValue: URL {
    url
  }

  public func withUnsafeBufferPointer<R>(for attachment: borrowing Attachment<Self>, _ body: (UnsafeRawBufferPointer) throws -> R) throws -> R {
    try data.withUnsafeBytes(body)
  }

  public borrowing func preferredName(for attachment: borrowing Attachment<Self>, basedOn suggestedName: String) -> String {
    // What extension should we have on the filename so that it has the same
    // type as the original file (or, in the case of a compressed directory, is
    // a zip file?)
    let preferredPathExtension = if isCompressedDirectory {
      "zip"
    } else {
      url.pathExtension
    }

    // What path extension is on the suggested name already?
    let nsSuggestedName = suggestedName as NSString
    let suggestedPathExtension = nsSuggestedName.pathExtension

    // If the suggested name's extension isn't what we would prefer, append the
    // preferred extension.
    if !preferredPathExtension.isEmpty,
       suggestedPathExtension.caseInsensitiveCompare(preferredPathExtension) != .orderedSame,
       let result = nsSuggestedName.appendingPathExtension(preferredPathExtension) {
      return result
    }

    return suggestedName
  }
}
#endif