[clang-tools-extra] [clangd] Add tweak for turning an unscoped into a scoped enum (PR #67645)

[via cfe-commits]

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@@ -0,0 +1,222 @@
+//===--- ScopifyEnum.cpp --------------------------------------- -*- 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "ParsedAST.h"
+#include "XRefs.h"
+#include "refactor/Tweak.h"
+#include "clang/Basic/SourceLocation.h"
+#include "clang/Basic/SourceManager.h"
+#include "clang/Tooling/Core/Replacement.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Error.h"
+
+#include <functional>
+
+namespace clang::clangd {
+namespace {
+
+/// Turns an unscoped into a scoped enum type.
+/// Before:
+///   enum E { EV1, EV2 };
+///        ^
+///   void f() { E e1 = EV1; }
+///
+/// After:
+///   enum class E { EV1, EV2 };
+///   void f() { E e1 = E::EV1; }
+///
+/// Note that the respective project code might not compile anymore
+/// if it made use of the now-gone implicit conversion to int.
+/// This is out of scope for this tweak.
+///
+/// TODO: In the above example, we could detect that the values
+///       start with the enum name, and remove that prefix.
+
+class ScopifyEnum : public Tweak {
+  const char *id() const final;
+  std::string title() const override { return "Convert to scoped enum"; }
+  llvm::StringLiteral kind() const override {
+    return CodeAction::REFACTOR_KIND;
+  }
+  bool prepare(const Selection &Inputs) override;
+  Expected<Tweak::Effect> apply(const Selection &Inputs) override;
+
+  using MakeReplacement =
+      std::function<tooling::Replacement(StringRef, StringRef, unsigned)>;
+  llvm::Error addClassKeywordToDeclarations();
+  llvm::Error scopifyEnumValues();
+  llvm::Error scopifyEnumValue(const EnumConstantDecl &CD, StringRef Prefix);
+  llvm::Expected<StringRef> getContentForFile(StringRef FilePath);
+  unsigned getOffsetFromPosition(const Position &Pos, StringRef Content) const;
+  llvm::Error addReplacementForReference(const ReferencesResult::Reference &Ref,
+                                         const MakeReplacement &GetReplacement);
+  llvm::Error addReplacement(StringRef FilePath, StringRef Content,
+                             const tooling::Replacement &Replacement);
+  Position getPosition(const Decl &D) const;
+
+  const EnumDecl *D = nullptr;
+  const Selection *S = nullptr;
+  SourceManager *SM = nullptr;
+  llvm::SmallVector<std::unique_ptr<llvm::MemoryBuffer>> ExtraBuffers;
+  llvm::StringMap<StringRef> ContentPerFile;
+  Effect E;
+};
+
+REGISTER_TWEAK(ScopifyEnum)
+
+bool ScopifyEnum::prepare(const Selection &Inputs) {
+  if (!Inputs.AST->getLangOpts().CPlusPlus11)
+    return false;
+  const SelectionTree::Node *N = Inputs.ASTSelection.commonAncestor();
+  if (!N)
+    return false;
+  D = N->ASTNode.get<EnumDecl>();
+  return D && !D->isScoped() && D->isThisDeclarationADefinition();
+}
+
+Expected<Tweak::Effect> ScopifyEnum::apply(const Selection &Inputs) {
+  S = &Inputs;
+  SM = &S->AST->getSourceManager();
+  E.FormatEdits = false;
+  ContentPerFile.insert(std::make_pair(SM->getFilename(D->getLocation()),
+                                       SM->getBufferData(SM->getMainFileID())));
+
+  if (auto Err = addClassKeywordToDeclarations())
+    return Err;
+  if (auto Err = scopifyEnumValues())
+    return Err;
+
+  return E;
+}
+
+llvm::Error ScopifyEnum::addClassKeywordToDeclarations() {
+  for (const auto &Ref :
+       findReferences(*S->AST, getPosition(*D), 0, S->Index, false)
+           .References) {
+    if (!(Ref.Attributes & ReferencesResult::Declaration))
+      continue;
+
+    static const auto MakeReplacement = [](StringRef FilePath,
+                                           StringRef Content, unsigned Offset) {
+      return tooling::Replacement(FilePath, Offset, 0, "class ");
+    };
+    if (auto Err = addReplacementForReference(Ref, MakeReplacement))
+      return Err;
+  }
+  return llvm::Error::success();
+}
+
+llvm::Error ScopifyEnum::scopifyEnumValues() {
+  std::string PrefixToInsert(D->getName().data());
+  PrefixToInsert += "::";
+  for (auto It = D->enumerator_begin(); It != D->enumerator_end(); ++It) {
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5chmidti wrote:

You can use `EnumDecl::enumerators` for a range-for here

https://github.com/llvm/llvm-project/pull/67645