//===--- CurrentSourceLocExprScope.h ----------------------------*- C++ -*-===//

//

//                     The LLVM Compiler Infrastructure

//

// This file is distributed under the University of Illinois Open Source

// License. See LICENSE.TXT for details.

//

//===----------------------------------------------------------------------===//

//

//  This file defines types used to track the current context needed to evaluate

//  a SourceLocExpr.

//

//===----------------------------------------------------------------------===//

#ifndef LLVM_CLANG_AST_CURRENT_SOURCE_LOC_EXPR_SCOPE_H

#define LLVM_CLANG_AST_CURRENT_SOURCE_LOC_EXPR_SCOPE_H

#include <cassert>

namespace clang {

class Expr;

/// Represents the current source location and context used to determine the

/// value of the source location builtins (ex. __builtin_LINE), including the

/// context of default argument and default initializer expressions.

class CurrentSourceLocExprScope {

  /// The CXXDefaultArgExpr or CXXDefaultInitExpr we're currently evaluating.

  const Expr *DefaultExpr = nullptr;

public:

  /// A RAII style scope guard used for tracking the current source

  /// location and context as used by the source location builtins

  /// (ex. __builtin_LINE).

  class SourceLocExprScopeGuard;

  const Expr *getDefaultExpr() const { return DefaultExpr; }

  explicit CurrentSourceLocExprScope() = default;

private:

  explicit CurrentSourceLocExprScope(const Expr *DefaultExpr)

      : DefaultExpr(DefaultExpr) {}

  CurrentSourceLocExprScope(CurrentSourceLocExprScope const &) = default;

  CurrentSourceLocExprScope &

  operator=(CurrentSourceLocExprScope const &) = default;

};

class CurrentSourceLocExprScope::SourceLocExprScopeGuard {

public:

  SourceLocExprScopeGuard(const Expr *DefaultExpr,

                          CurrentSourceLocExprScope &Current)

      : Current(Current), OldVal(Current), Enable(false) {

    assert(DefaultExpr && "the new scope should not be empty");

    if ((Enable = (Current.getDefaultExpr() == nullptr)))

      Current = CurrentSourceLocExprScope(DefaultExpr);

  }

  ~SourceLocExprScopeGuard() {

    if (Enable)

      Current = OldVal;

  }

private:

  SourceLocExprScopeGuard(SourceLocExprScopeGuard const &) = delete;

  SourceLocExprScopeGuard &operator=(SourceLocExprScopeGuard const &) = delete;

  CurrentSourceLocExprScope &Current;

  CurrentSourceLocExprScope OldVal;

  bool Enable;

};

} // end namespace clang

#endif // LLVM_CLANG_AST_CURRENT_SOURCE_LOC_EXPR_SCOPE_H