//===--- AccessScopeChecker.cpp - Access calculation helpers ----- --------===//
//
// This source file is part of the Swift.org open source project
//
// Copyright (c) 2014 - 2017 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 the list of Swift project authors
//
//===----------------------------------------------------------------------===//

#include "swift/AST/AccessScopeChecker.h"
#include "swift/AST/Module.h"
#include "swift/AST/TypeRepr.h"
#include "swift/AST/Types.h"

using namespace swift;

//----------------------------------------------------------------------------//
// Access Scope Checkers
//----------------------------------------------------------------------------//

AccessScopeChecker::AccessScopeChecker(const DeclContext *useDC,
                                       bool treatUsableFromInlineAsPublic)
  : File(useDC->getParentSourceFile()),
    TreatUsableFromInlineAsPublic(treatUsableFromInlineAsPublic),
    Context(File->getASTContext()) {}

bool
AccessScopeChecker::visitDecl(ValueDecl *VD) {
  if (!VD || isa<GenericTypeParamDecl>(VD))
    return true;

  // FIXME: Figure out why AssociatedTypeDecls don't always have an access
  // level here.
  if (!VD->hasAccess()) {
    if (isa<AssociatedTypeDecl>(VD))
      return true;
  }

  auto AS = VD->getFormalAccessScope(File, TreatUsableFromInlineAsPublic);
  Scope = Scope->intersectWith(AS);
  return Scope.hasValue();
}

TypeReprAccessScopeChecker::TypeReprAccessScopeChecker(const DeclContext *useDC,
                                                       bool treatUsableFromInlineAsPublic)
  : AccessScopeChecker(useDC, treatUsableFromInlineAsPublic) {
}

bool
TypeReprAccessScopeChecker::walkToTypeReprPre(TypeRepr *TR) {
  if (auto CITR = dyn_cast<ComponentIdentTypeRepr>(TR))
    return visitDecl(CITR->getBoundDecl());
  return true;
}

bool
TypeReprAccessScopeChecker::walkToTypeReprPost(TypeRepr *TR) {
  return Scope.hasValue();
}

Optional<AccessScope>
TypeReprAccessScopeChecker::getAccessScope(TypeRepr *TR, const DeclContext *useDC,
                                           bool treatUsableFromInlineAsPublic) {
  TypeReprAccessScopeChecker checker(useDC, treatUsableFromInlineAsPublic);
  TR->walk(checker);
  return checker.Scope;
}

TypeAccessScopeChecker::TypeAccessScopeChecker(const DeclContext *useDC,
                                               bool treatUsableFromInlineAsPublic,
                                               bool canonicalizeParentTypes)
  : AccessScopeChecker(useDC, treatUsableFromInlineAsPublic),
    CanonicalizeParentTypes(canonicalizeParentTypes) {}

TypeWalker::Action
TypeAccessScopeChecker::walkToTypePre(Type T) {
  ValueDecl *VD;
  if (auto *BNAD = dyn_cast<NameAliasType>(T.getPointer())) {
    if (CanonicalizeParentTypes &&
        BNAD->getDecl()->getUnderlyingTypeLoc().getType()->hasTypeParameter())
      VD = nullptr;
    else
      VD = BNAD->getDecl();
  }
  else if (auto *NTD = T->getAnyNominal())
    VD = NTD;
  else
    VD = nullptr;

  if (!visitDecl(VD))
    return Action::Stop;

  if (!CanonicalizeParentTypes) {
    return Action::Continue;
  }

  Type nominalParentTy;
  if (auto nominalTy = dyn_cast<NominalType>(T.getPointer())) {
    nominalParentTy = nominalTy->getParent();
  } else if (auto genericTy = dyn_cast<BoundGenericType>(T.getPointer())) {
    nominalParentTy = genericTy->getParent();
    for (auto genericArg : genericTy->getGenericArgs())
      genericArg.walk(*this);
  } else if (auto NameAliasTy =
             dyn_cast<NameAliasType>(T.getPointer())) {
    // The parent type would have been lost previously, so look right through
    // this type.
    if (NameAliasTy->getDecl()->getUnderlyingTypeLoc().getType()
        ->hasTypeParameter())
      Type(NameAliasTy->getSinglyDesugaredType()).walk(*this);
  } else {
    return Action::Continue;
  }

  if (nominalParentTy)
    nominalParentTy->getCanonicalType().walk(*this);
  return Action::SkipChildren;
}

Optional<AccessScope>
TypeAccessScopeChecker::getAccessScope(Type T, const DeclContext *useDC,
                                       bool treatUsableFromInlineAsPublic,
                                       bool canonicalizeParentTypes) {
  TypeAccessScopeChecker checker(useDC, treatUsableFromInlineAsPublic,
                                 canonicalizeParentTypes);
  T.walk(checker);
  return checker.Scope;
}