//===- UnresolvedSet.h - Unresolved sets of declarations --------*- C++ -*-===//

//

// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

// See https://llvm.org/LICENSE.txt for license information.

// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

//

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

//

//  This file defines the UnresolvedSet class, which is used to store

//  collections of declarations in the AST.

//

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

#ifndef LLVM_CLANG_AST_UNRESOLVEDSET_H

#define LLVM_CLANG_AST_UNRESOLVEDSET_H

#include "clang/AST/DeclAccessPair.h"

#include "clang/Basic/LLVM.h"

#include "clang/Basic/Specifiers.h"

#include "llvm/ADT/ArrayRef.h"

#include "llvm/ADT/SmallVector.h"

#include "llvm/ADT/iterator.h"

#include <cstddef>

#include <iterator>

namespace clang {

class NamedDecl;

/// The iterator over UnresolvedSets.  Serves as both the const and

/// non-const iterator.

class UnresolvedSetIterator : public llvm::iterator_adaptor_base<

                                  UnresolvedSetIterator, DeclAccessPair *,

                                  std::random_access_iterator_tag, NamedDecl *,

                                  std::ptrdiff_t, NamedDecl *, NamedDecl *> {

  friend class ASTUnresolvedSet;

  friend class OverloadExpr;

  friend class UnresolvedSetImpl;

  explicit UnresolvedSetIterator(DeclAccessPair *Iter)

      : iterator_adaptor_base(Iter) {}

  explicit UnresolvedSetIterator(const DeclAccessPair *Iter)

      : iterator_adaptor_base(const_cast<DeclAccessPair *>(Iter)) {}

public:

  // Work around a bug in MSVC 2013 where explicitly default constructed

  // temporaries with defaulted ctors are not zero initialized.

  UnresolvedSetIterator() : iterator_adaptor_base(nullptr) {}

  NamedDecl *getDecl() const { return I->getDecl(); }

  void setDecl(NamedDecl *ND) const { return I->setDecl(ND); }

  AccessSpecifier getAccess() const { return I->getAccess(); }

  void setAccess(AccessSpecifier AS) { I->setAccess(AS); }

  const DeclAccessPair &getPair() const { return *I; }

  NamedDecl *operator*() const { return getDecl(); }

  NamedDecl *operator->() const { return **this; }

};

/// A set of unresolved declarations.

class UnresolvedSetImpl {

  using DeclsTy = SmallVectorImpl<DeclAccessPair>;

  // Don't allow direct construction, and only permit subclassing by

  // UnresolvedSet.

private:

  template <unsigned N> friend class UnresolvedSet;

  UnresolvedSetImpl() = default;

  UnresolvedSetImpl(const UnresolvedSetImpl &) = default;

  UnresolvedSetImpl &operator=(const UnresolvedSetImpl &) = default;

  // FIXME: Switch these to "= default" once MSVC supports generating move ops

  UnresolvedSetImpl(UnresolvedSetImpl &&) {}

  UnresolvedSetImpl &operator=(UnresolvedSetImpl &&) { return *this; }

public:

  // We don't currently support assignment through this iterator, so we might

  // as well use the same implementation twice.

  using iterator = UnresolvedSetIterator;

  using const_iterator = UnresolvedSetIterator;

  iterator begin() { return iterator(decls().begin()); }

  iterator end() { return iterator(decls().end()); }

  const_iterator begin() const { return const_iterator(decls().begin()); }

  const_iterator end() const { return const_iterator(decls().end()); }

  ArrayRef<DeclAccessPair> pairs() const { return decls(); }

  void addDecl(NamedDecl *D) {

    addDecl(D, AS_none);

  }

  void addDecl(NamedDecl *D, AccessSpecifier AS) {

    decls().push_back(DeclAccessPair::make(D, AS));

  }

  /// Replaces the given declaration with the new one, once.

  ///

  /// \return true if the set changed

  bool replace(const NamedDecl* Old, NamedDecl *New) {

    for (DeclsTy::iterator I = decls().begin(), E = decls().end(); I != E; ++I)

      if (I->getDecl() == Old)

        return (I->setDecl(New), true);

    return false;

  }

  /// Replaces the declaration at the given iterator with the new one,

  /// preserving the original access bits.

  void replace(iterator I, NamedDecl *New) { I.I->setDecl(New); }

  void replace(iterator I, NamedDecl *New, AccessSpecifier AS) {

    I.I->set(New, AS);

  }

  void erase(unsigned I) { decls()[I] = decls().pop_back_val(); }

  void erase(iterator I) { *I.I = decls().pop_back_val(); }

  void setAccess(iterator I, AccessSpecifier AS) { I.I->setAccess(AS); }

  void clear() { decls().clear(); }

  void truncate(unsigned N) { decls().truncate(N); }

  bool empty() const { return decls().empty(); }

  unsigned size() const { return decls().size(); }

  void append(iterator I, iterator E) { decls().append(I.I, E.I); }

  template<typename Iter> void assign(Iter I, Iter E) { decls().assign(I, E); }

  DeclAccessPair &operator[](unsigned I) { return decls()[I]; }

  const DeclAccessPair &operator[](unsigned I) const { return decls()[I]; }

private:

  // These work because the only permitted subclass is UnresolvedSetImpl

  DeclsTy &decls() {

    return *reinterpret_cast<DeclsTy*>(this);

  }

  const DeclsTy &decls() const {

    return *reinterpret_cast<const DeclsTy*>(this);

  }

};

/// A set of unresolved declarations.

template <unsigned InlineCapacity> class UnresolvedSet :

    public UnresolvedSetImpl {

  SmallVector<DeclAccessPair, InlineCapacity> Decls;

};

} // namespace clang

#endif // LLVM_CLANG_AST_UNRESOLVEDSET_H