//===--- USRGeneration.cpp - Routines for USR generation ------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#include "swift/AST/ASTContext.h"
#include "swift/AST/Module.h"
#include "swift/AST/USRGeneration.h"
#include "swift/AST/Mangle.h"
#include "llvm/ADT/SmallString.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Support/raw_ostream.h"
#include "clang/AST/ASTContext.h"
#include "clang/AST/Attr.h"
#include "clang/Index/USRGeneration.h"
#include "clang/Lex/PreprocessingRecord.h"
#include "clang/Lex/Preprocessor.h"

using namespace swift;
using namespace ide;

static inline StringRef getUSRSpacePrefix() {
  return "s:";
}

bool ide::printTypeUSR(Type Ty, raw_ostream &OS) {
  using namespace Mangle;
  Mangler Mangler(true);
  Mangler.mangleTypeForDebugger(Ty->getRValueType(), nullptr);
  Mangler.finalize(OS);
  return false;
}

bool ide::printDeclTypeUSR(const ValueDecl *D, raw_ostream &OS) {
  using namespace Mangle;
  Mangler Mangler(true);
  Mangler.mangleDeclTypeForDebugger(D);
  Mangler.finalize(OS);
  return false;
}

bool ide::printDeclUSR(const ValueDecl *D, raw_ostream &OS) {
  using namespace Mangle;

  if (!isa<FuncDecl>(D) && !D->hasName())
    return true; // Ignore.
  if (D->getModuleContext()->isBuiltinModule())
    return true; // Ignore.

  ValueDecl *VD = const_cast<ValueDecl *>(D);

  auto interpretAsClangNode = [](const ValueDecl *D)->ClangNode {
    ClangNode ClangN = D->getClangNode();
    if (auto ClangD = ClangN.getAsDecl()) {
      // NSErrorDomain causes the clang enum to be imported like this:
      //
      // struct MyError {
      //     enum Code : Int32 {
      //         case errFirst
      //         case errSecond
      //     }
      //     static var errFirst: MyError.Code { get }
      //     static var errSecond: MyError.Code { get }
      // }
      //
      // The clang enum and enum constants are associated with both the
      // struct/nested enum, and the static vars/enum cases.
      // But we want unique USRs for the above symbols, so use the clang USR
      // for the enum and enum cases, and the Swift USR for the struct and vars.
      //
      if (isa<clang::EnumDecl>(ClangD)) {
        if (ClangD->hasAttr<clang::NSErrorDomainAttr>() && isa<StructDecl>(D))
          return ClangNode();
      } else if (auto *ClangEnumConst = dyn_cast<clang::EnumConstantDecl>(ClangD)) {
        if (auto *ClangEnum = dyn_cast<clang::EnumDecl>(ClangEnumConst->getDeclContext())) {
          if (ClangEnum->hasAttr<clang::NSErrorDomainAttr>() && isa<VarDecl>(D))
            return ClangNode();
        }
      }
    }
    return ClangN;
  };

  if (ClangNode ClangN = interpretAsClangNode(D)) {
    llvm::SmallString<128> Buf;
    if (auto ClangD = ClangN.getAsDecl()) {
      bool Ignore = clang::index::generateUSRForDecl(ClangD, Buf);
      if (!Ignore)
        OS << Buf.str();
      return Ignore;
    }

    auto &Importer = *D->getASTContext().getClangModuleLoader();

    auto ClangMacroInfo = ClangN.getAsMacro();
    auto PPRecord = Importer.getClangPreprocessor().getPreprocessingRecord();
    assert(PPRecord && "Clang importer should be created with "
                       "-detailed-preprocessing-record option");
    auto ClangMacroDef = PPRecord->findMacroDefinition(ClangMacroInfo);

    bool Ignore = clang::index::generateUSRForMacro(
        ClangMacroDef, Importer.getClangASTContext().getSourceManager(), Buf);
    if (!Ignore)
      OS << Buf.str();
    return Ignore;
  }

  if (!D->hasType())
    return true;

  // FIXME: mangling 'self' in destructors crashes in mangler.
  if (isa<ParamDecl>(VD) && isa<DestructorDecl>(VD->getDeclContext()))
    return true;

  OS << getUSRSpacePrefix();
  Mangler Mangler;

  Mangler.bindGenericParameters(VD->getDeclContext());

  if (auto Ctor = dyn_cast<ConstructorDecl>(VD)) {
    Mangler.mangleConstructorEntity(Ctor, /*isAllocating=*/false,
                                    /*uncurryingLevel=*/0);
  } else if (auto Dtor = dyn_cast<DestructorDecl>(VD)) {
    Mangler.mangleDestructorEntity(Dtor, /*isDeallocating=*/false);
  } else if (auto NTD = dyn_cast<NominalTypeDecl>(VD)) {
    Mangler.mangleNominalType(NTD);
  } else if (isa<TypeAliasDecl>(VD) || isa<AssociatedTypeDecl>(VD)) {
    Mangler.mangleContextOf(VD);
    Mangler.mangleDeclName(VD);
  } else {
    Mangler.mangleEntity(VD, /*uncurryingLevel=*/0);
  }

  Mangler.finalize(OS);
  return false;
}

bool ide::printAccessorUSR(const AbstractStorageDecl *D, AccessorKind AccKind,
                           llvm::raw_ostream &OS) {
  using namespace Mangle;

  // AccKind should always be either IsGetter or IsSetter here, based
  // on whether a reference is a mutating or non-mutating use.  USRs
  // aren't supposed to reflect implementation differences like stored
  // vs. addressed vs. observing.
  //
  // On the other side, the implementation indexer should be
  // registering the getter/setter USRs independently of how they're
  // actually implemented.  So a stored variable should still have
  // getter/setter USRs (pointing to the variable declaration), and an
  // addressed variable should have its "getter" point at the
  // addressor.

  AbstractStorageDecl *SD = const_cast<AbstractStorageDecl*>(D);
  OS << getUSRSpacePrefix();
  Mangler Mangler;
  Mangler.mangleAccessorEntity(AccKind, AddressorKind::NotAddressor, SD);
  Mangler.finalize(OS);
  return false;
}

bool ide::printExtensionUSR(const ExtensionDecl *ED, raw_ostream &OS) {
  if (ED->getExtendedType().isNull())
    return true;

  // We make up a unique usr for each extension by combining a prefix
  // and the USR of the first value member of the extension.
  for (auto D : ED->getMembers()) {
    if (auto VD = dyn_cast<ValueDecl>(D)) {
      OS << getUSRSpacePrefix() << "e:";
      return printDeclUSR(VD, OS);
    }
  }
  if (ED->getExtendedType() && ED->getExtendedType()->getAnyNominal()) {
    OS << getUSRSpacePrefix() << "e:";
    printDeclUSR(ED->getExtendedType()->getAnyNominal(), OS);
  } else {
    return true;
  }
  for (auto Inherit : ED->getInherited()) {
    if (auto T = Inherit.getType()) {
      if (T->getAnyNominal())
        return printDeclUSR(T->getAnyNominal(), OS);
    }
  }
  return true;
}