stdlib/public/core/CommandLine.swift

//===----------------------------------------------------------------------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2016 Apple Inc. and the Swift project authors
// Licensed under Apache License v2.0 with Runtime Library Exception
//
// See http://swift.org/LICENSE.txt for license information
// See http://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
//
//===----------------------------------------------------------------------===//

import SwiftShims

/// Command-line arguments for the current process.
public enum CommandLine {
  /// The backing static variable for argument count may come either from the
  /// entry point or it may need to be computed e.g. if we're in the REPL.
  @_versioned
  internal static var _argc: Int32 = Int32()

  /// The backing static variable for arguments may come either from the
  /// entry point or it may need to be computed e.g. if we're in the REPL.
  ///
  /// Care must be taken to ensure that `_swift_stdlib_getUnsafeArgvArgc` is
  /// not invoked more times than is necessary (at most once).
  @_versioned
  internal static var _unsafeArgv:
    UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>
      =  _swift_stdlib_getUnsafeArgvArgc(&_argc)

  /// Access to the raw argc value from C.
  public static var argc: Int32 {
    _ = CommandLine.unsafeArgv // Force evaluation of argv.
    return _argc
  }

  /// Access to the raw argv value from C. Accessing the argument vector
  /// through this pointer is unsafe.
  public static var unsafeArgv:
    UnsafeMutablePointer<UnsafeMutablePointer<Int8>?> {
    return _unsafeArgv
  }

  /// Access to the swift arguments, also use lazy initialization of static
  /// properties to safely initialize the swift arguments.
  public static var arguments: [String]
    = (0..<Int(argc)).map { String(cString: _unsafeArgv[$0]!) }
}

// FIXME(ABI): Remove this and the entrypoints in SILGen.
@_transparent
public // COMPILER_INTRINSIC
func _stdlib_didEnterMain(
  argc: Int32, argv: UnsafeMutablePointer<UnsafeMutablePointer<Int8>?>
) {
  // Initialize the CommandLine.argc and CommandLine.unsafeArgv variables with the
  // values that were passed in to main.
  CommandLine._argc = Int32(argc)
  CommandLine._unsafeArgv = argv
}

// FIXME: Move this to HashedCollections.swift.gyb
internal class _Box<Wrapped> {
  internal var _value: Wrapped
  internal init(_ value: Wrapped) { self._value = value }
}