//===--- CaptureInfo.h - Data Structure for Capture Lists -------*- C++ -*-===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2015 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
//
//===----------------------------------------------------------------------===//

#ifndef SWIFT_AST_CAPTURE_INFO_H
#define SWIFT_AST_CAPTURE_INFO_H

#include "swift/Basic/LLVM.h"
#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/PointerIntPair.h"
#include <vector>

namespace llvm {
class raw_ostream;
}

namespace swift {
class ValueDecl;
class FuncDecl;

/// CapturedValue includes both the declaration being captured, along with flags
/// that indicate how it is captured.
class CapturedValue {
  llvm::PointerIntPair<ValueDecl*, 2, unsigned> Value;
public:
  enum {
    /// IsDirect is set when a VarDecl with storage *and* accessors is captured
    /// by its storage address.  This happens in the accessors for the VarDecl.
    IsDirect = 1 << 0,

    /// IsNoEscape is set when a vardecl is captured by a noescape closure, and
    /// thus has its lifetime guaranteed.  It can be closed over by a fixed
    /// address if it has storage.
    IsNoEscape = 1 << 1
  };

  CapturedValue(ValueDecl *D, unsigned Flags) : Value(D, Flags) {}

  bool isDirect() const { return Value.getInt() & IsDirect; }
  bool isNoEscape() const { return Value.getInt() & IsNoEscape; }

  ValueDecl *getDecl() const { return Value.getPointer(); }

  unsigned getFlags() const { return Value.getInt(); }

  bool operator==(CapturedValue RHS) const {
    return Value == RHS.Value;
  }

  bool operator!=(CapturedValue RHS) const {
    return Value != RHS.Value;
  }

  bool operator<(CapturedValue RHS) const {
    return Value < RHS.Value;
  }
};



/// \brief Stores information about captured variables.
class CaptureInfo {
  llvm::PointerIntPair<const CapturedValue *, 1, bool> CapturesAndComputed;
  size_t Count = 0;

public:
  bool hasBeenComputed() { return CapturesAndComputed.getInt(); }
  bool empty() { return Count == 0; }

  ArrayRef<CapturedValue> getCaptures() const {
    return llvm::makeArrayRef(CapturesAndComputed.getPointer(), Count);
  }
  void setCaptures(ArrayRef<CapturedValue> C) {
    CapturesAndComputed.setPointerAndInt(C.data(), true);
    Count = C.size();
  }

  /// \brief Return a filtered list of the captures for this function,
  /// filtering out global variables.  This function returns the list that
  /// actually needs to be closed over.
  ///
  void getLocalCaptures(SmallVectorImpl<CapturedValue> &Result) const;

  /// \returns true if getLocalCaptures() will return a non-empty list.
  bool hasLocalCaptures() const;

  void dump() const;
  void print(raw_ostream &OS) const;
};

} // namespace swift

#endif // LLVM_SWIFT_AST_CAPTURE_INFO_H