[clangd] Add support TextDocumentEdit.

This is an initial patch to add TextDocumentEdit (versioned edits) support in
clangd, the scope is minimal:

- add and extend the corresponding protocol structures
- propagate the documentChanges for diagnostic codeactions (our motivated case)

Differential Revision: https://reviews.llvm.org/D148783

clang-tools-extra/clangd/ClangdLSPServer.cpp

@@ -45,6 +45,7 @@
 #include <mutex>
 #include <optional>
 #include <string>
+#include <utility>
 #include <vector>
 
 namespace clang {
@@ -95,6 +96,26 @@ CodeAction toCodeAction(const ClangdServer::TweakRef &T, const URIForFile &File,
   return CA;
 }
 
+/// Convert from Fix to LSP CodeAction.
+CodeAction toCodeAction(const Fix &F, const URIForFile &File,
+                        const std::optional<int64_t> &Version,
+                        bool SupportsDocumentChanges) {
+  CodeAction Action;
+  Action.title = F.Message;
+  Action.kind = std::string(CodeAction::QUICKFIX_KIND);
+  Action.edit.emplace();
+  if (!SupportsDocumentChanges) {
+    Action.edit->changes.emplace();
+    (*Action.edit->changes)[File.uri()] = {F.Edits.begin(), F.Edits.end()};
+  } else {
+    Action.edit->documentChanges.emplace();
+    TextDocumentEdit& Edit = Action.edit->documentChanges->emplace_back();
+    Edit.textDocument = VersionedTextDocumentIdentifier{{File}, Version};
+    Edit.edits = {F.Edits.begin(), F.Edits.end()};
+  }
+  return Action;
+}
+
 void adjustSymbolKinds(llvm::MutableArrayRef<DocumentSymbol> Syms,
                        SymbolKindBitset Kinds) {
   for (auto &S : Syms) {
@@ -487,6 +508,7 @@ void ClangdLSPServer::onInitialize(const InitializeParams &Params,
       Params.capabilities.HierarchicalDocumentSymbol;
   SupportsReferenceContainer = Params.capabilities.ReferenceContainer;
   SupportFileStatus = Params.initializationOptions.FileStatus;
+  SupportsDocumentChanges = Params.capabilities.DocumentChanges;
   HoverContentFormat = Params.capabilities.HoverContentFormat;
   Opts.LineFoldingOnly = Params.capabilities.LineFoldingOnly;
   SupportsOffsetsInSignatureHelp = Params.capabilities.OffsetsInSignatureHelp;
@@ -761,8 +783,10 @@ void ClangdLSPServer::onCommandApplyTweak(const TweakArgs &Args,
       return Reply(std::move(Err));
 
     WorkspaceEdit WE;
+    // FIXME: use documentChanges when SupportDocumentChanges is true.
+    WE.changes.emplace();
     for (const auto &It : R->ApplyEdits) {
-      WE.changes[URI::createFile(It.first()).toString()] =
+      (*WE.changes)[URI::createFile(It.first()).toString()] =
           It.second.asTextEdits();
     }
     // ApplyEdit will take care of calling Reply().
@@ -833,8 +857,12 @@ void ClangdLSPServer::onRename(const RenameParams &Params,
                    if (auto Err = validateEdits(*Server, R->GlobalChanges))
                      return Reply(std::move(Err));
                    WorkspaceEdit Result;
+                   // FIXME: use documentChanges if SupportDocumentChanges is
+                   // true.
+                   Result.changes.emplace();
                    for (const auto &Rep : R->GlobalChanges) {
-                     Result.changes[URI::createFile(Rep.first()).toString()] =
+                     (*Result
+                           .changes)[URI::createFile(Rep.first()).toString()] =
                          Rep.second.asTextEdits();
                    }
                    Reply(Result);
@@ -984,8 +1012,8 @@ void ClangdLSPServer::onCodeAction(const CodeActionParams &Params,
   std::vector<CodeAction> FixIts;
   if (KindAllowed(CodeAction::QUICKFIX_KIND)) {
     for (const Diagnostic &D : Params.context.diagnostics) {
-      for (auto &F : getFixes(File.file(), D)) {
-        FixIts.push_back(toCodeAction(F, Params.textDocument.uri));
+      for (auto &CA : getFixes(File.file(), D)) {
+        FixIts.push_back(CA);
         FixIts.back().diagnostics = {D};
       }
     }
@@ -1663,8 +1691,8 @@ void ClangdLSPServer::profile(MemoryTree &MT) const {
     Server->profile(MT.child("clangd_server"));
 }
 
-std::vector<Fix> ClangdLSPServer::getFixes(llvm::StringRef File,
-                                           const clangd::Diagnostic &D) {
+std::vector<CodeAction> ClangdLSPServer::getFixes(llvm::StringRef File,
+                                                  const clangd::Diagnostic &D) {
   std::lock_guard<std::mutex> Lock(FixItsMutex);
   auto DiagToFixItsIter = FixItsMap.find(File);
   if (DiagToFixItsIter == FixItsMap.end())
@@ -1710,8 +1738,18 @@ void ClangdLSPServer::onDiagnosticsReady(PathRef File, llvm::StringRef Version,
   for (auto &Diag : Diagnostics) {
     toLSPDiags(Diag, Notification.uri, DiagOpts,
                [&](clangd::Diagnostic Diag, llvm::ArrayRef<Fix> Fixes) {
-                 auto &FixItsForDiagnostic = LocalFixIts[Diag];
-                 llvm::copy(Fixes, std::back_inserter(FixItsForDiagnostic));
+                 std::vector<CodeAction> CodeActions;
+                 for (const auto &Fix : Fixes)
+                   CodeActions.push_back(toCodeAction(Fix, Notification.uri,
+                                                      Notification.version,
+                                                      SupportsDocumentChanges));
+
+                 if (DiagOpts.EmbedFixesInDiagnostics) {
+                   Diag.codeActions.emplace(CodeActions);
+                   if (Diag.codeActions->size() == 1)
+                     Diag.codeActions->front().isPreferred = true;
+                 }
+                 LocalFixIts[Diag] = std::move(CodeActions);
                  Notification.diagnostics.push_back(std::move(Diag));
                });
   }

clang-tools-extra/clangd/ClangdLSPServer.h

@@ -21,6 +21,7 @@
 #include "llvm/Support/JSON.h"
 #include <chrono>
 #include <cstddef>
+#include <cstdint>
 #include <memory>
 #include <optional>
 #include <vector>
@@ -197,7 +198,8 @@ class ClangdLSPServer : private ClangdServer::Callbacks,
                  Callback<llvm::json::Value> Reply);
 
   void bindMethods(LSPBinder &, const ClientCapabilities &Caps);
-  std::vector<Fix> getFixes(StringRef File, const clangd::Diagnostic &D);
+  std::vector<CodeAction> getFixes(StringRef File, const clangd::Diagnostic &D);
+
 
   /// Checks if completion request should be ignored. We need this due to the
   /// limitation of the LSP. Per LSP, a client sends requests for all "trigger
@@ -231,10 +233,12 @@ class ClangdLSPServer : private ClangdServer::Callbacks,
   std::atomic<bool> IsBeingDestroyed = {false};
 
   std::mutex FixItsMutex;
-  typedef std::map<clangd::Diagnostic, std::vector<Fix>, LSPDiagnosticCompare>
+  typedef std::map<clangd::Diagnostic, std::vector<CodeAction>,
+                   LSPDiagnosticCompare>
       DiagnosticToReplacementMap;
   /// Caches FixIts per file and diagnostics
-  llvm::StringMap<DiagnosticToReplacementMap> FixItsMap;
+  llvm::StringMap<DiagnosticToReplacementMap>
+      FixItsMap;
   // Last semantic-tokens response, for incremental requests.
   std::mutex SemanticTokensMutex;
   llvm::StringMap<SemanticTokens> LastSemanticTokens;
@@ -271,6 +275,8 @@ class ClangdLSPServer : private ClangdServer::Callbacks,
   MarkupKind HoverContentFormat = MarkupKind::PlainText;
   /// Whether the client supports offsets for parameter info labels.
   bool SupportsOffsetsInSignatureHelp = false;
+  /// Whether the client supports the versioned document changes.
+  bool SupportsDocumentChanges = false;
   std::mutex BackgroundIndexProgressMutex;
   enum class BackgroundIndexProgress {
     // Client doesn't support reporting progress. No transitions possible.

clang-tools-extra/clangd/Diagnostics.cpp

@@ -423,15 +423,6 @@ llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const Diag &D) {
   return OS;
 }
 
-CodeAction toCodeAction(const Fix &F, const URIForFile &File) {
-  CodeAction Action;
-  Action.title = F.Message;
-  Action.kind = std::string(CodeAction::QUICKFIX_KIND);
-  Action.edit.emplace();
-  Action.edit->changes[File.uri()] = {F.Edits.begin(), F.Edits.end()};
-  return Action;
-}
-
 Diag toDiag(const llvm::SMDiagnostic &D, Diag::DiagSource Source) {
   Diag Result;
   Result.Message = D.getMessage().str();
@@ -499,13 +490,6 @@ void toLSPDiags(
   case Diag::Unknown:
     break;
   }
-  if (Opts.EmbedFixesInDiagnostics) {
-    Main.codeActions.emplace();
-    for (const auto &Fix : D.Fixes)
-      Main.codeActions->push_back(toCodeAction(Fix, File));
-    if (Main.codeActions->size() == 1)
-      Main.codeActions->front().isPreferred = true;
-  }
   if (Opts.SendDiagnosticCategory && !D.Category.empty())
     Main.category = D.Category;
 

clang-tools-extra/clangd/Diagnostics.h

@@ -120,9 +120,6 @@ void toLSPDiags(
     const Diag &D, const URIForFile &File, const ClangdDiagnosticOptions &Opts,
     llvm::function_ref<void(clangd::Diagnostic, llvm::ArrayRef<Fix>)> OutFn);
 
-/// Convert from Fix to LSP CodeAction.
-CodeAction toCodeAction(const Fix &D, const URIForFile &File);
-
 /// Convert from clang diagnostic level to LSP severity.
 int getSeverity(DiagnosticsEngine::Level L);
 

clang-tools-extra/clangd/Protocol.cpp

@@ -197,6 +197,17 @@ llvm::json::Value toJSON(const TextEdit &P) {
   };
 }
 
+bool fromJSON(const llvm::json::Value &Params, TextDocumentEdit &R,
+              llvm::json::Path P) {
+  llvm::json::ObjectMapper O(Params, P);
+  return O && O.map("textDocument", R.textDocument) && O.map("edits", R.edits);
+}
+llvm::json::Value toJSON(const TextDocumentEdit &P) {
+  llvm::json::Object Result{{"textDocument", P.textDocument},
+                            {"edits", P.edits}};
+  return Result;
+}
+
 llvm::raw_ostream &operator<<(llvm::raw_ostream &OS, const TextEdit &TE) {
   OS << TE.range << " => \"";
   llvm::printEscapedString(TE.newText, OS);
@@ -444,6 +455,10 @@ bool fromJSON(const llvm::json::Value &Params, ClientCapabilities &R,
       if (auto RefreshSupport = SemanticTokens->getBoolean("refreshSupport"))
         R.SemanticTokenRefreshSupport = *RefreshSupport;
     }
+    if (auto *WorkspaceEdit = Workspace->getObject("workspaceEdit")) {
+      if (auto DocumentChanges = WorkspaceEdit->getBoolean("documentChanges"))
+        R.DocumentChanges = *DocumentChanges;
+    }
   }
   if (auto *Window = O->getObject("window")) {
     if (auto WorkDoneProgress = Window->getBoolean("workDoneProgress"))
@@ -717,7 +732,8 @@ bool fromJSON(const llvm::json::Value &Params, CodeActionParams &R,
 bool fromJSON(const llvm::json::Value &Params, WorkspaceEdit &R,
               llvm::json::Path P) {
   llvm::json::ObjectMapper O(Params, P);
-  return O && O.map("changes", R.changes);
+  return O && O.map("changes", R.changes) &&
+         O.map("documentChanges", R.documentChanges);
 }
 
 bool fromJSON(const llvm::json::Value &Params, ExecuteCommandParams &R,
@@ -863,10 +879,16 @@ llvm::json::Value toJSON(const DocumentSymbol &S) {
 }
 
 llvm::json::Value toJSON(const WorkspaceEdit &WE) {
-  llvm::json::Object FileChanges;
-  for (auto &Change : WE.changes)
-    FileChanges[Change.first] = llvm::json::Array(Change.second);
-  return llvm::json::Object{{"changes", std::move(FileChanges)}};
+  llvm::json::Object Result;
+  if (WE.changes) {
+    llvm::json::Object FileChanges;
+    for (auto &Change : *WE.changes)
+      FileChanges[Change.first] = llvm::json::Array(Change.second);
+    Result["changes"] = std::move(FileChanges);
+  }
+  if (WE.documentChanges)
+    Result["documentChanges"] = *WE.documentChanges;
+  return Result;
 }
 
 bool fromJSON(const llvm::json::Value &Params, TweakArgs &A,

clang-tools-extra/clangd/Protocol.h

@@ -254,6 +254,17 @@ bool fromJSON(const llvm::json::Value &, TextEdit &, llvm::json::Path);
 llvm::json::Value toJSON(const TextEdit &);
 llvm::raw_ostream &operator<<(llvm::raw_ostream &, const TextEdit &);
 
+struct TextDocumentEdit {
+  /// The text document to change.
+  VersionedTextDocumentIdentifier textDocument;
+
+	/// The edits to be applied.
+  /// FIXME: support the AnnotatedTextEdit variant.
+  std::vector<TextEdit> edits;
+};
+bool fromJSON(const llvm::json::Value &, TextDocumentEdit &, llvm::json::Path);
+llvm::json::Value toJSON(const TextDocumentEdit &);
+
 struct TextDocumentItem {
   /// The text document's URI.
   URIForFile uri;
@@ -517,6 +528,9 @@ struct ClientCapabilities {
   /// server to the client.
   bool SemanticTokenRefreshSupport = false;
 
+  /// The client supports versioned document changes for WorkspaceEdit.
+  bool DocumentChanges = false;
+
   /// Whether the client supports the textDocument/inactiveRegions
   /// notification. This is a clangd extension.
   bool InactiveRegions = false;
@@ -970,12 +984,18 @@ struct CodeActionParams {
 };
 bool fromJSON(const llvm::json::Value &, CodeActionParams &, llvm::json::Path);
 
+/// The edit should either provide changes or documentChanges. If the client
+/// can handle versioned document edits and if documentChanges are present,
+/// the latter are preferred over changes.
 struct WorkspaceEdit {
   /// Holds changes to existing resources.
-  std::map<std::string, std::vector<TextEdit>> changes;
-
-  /// Note: "documentChanges" is not currently used because currently there is
-  /// no support for versioned edits.
+  std::optional<std::map<std::string, std::vector<TextEdit>>> changes;
+  /// Versioned document edits.
+  ///
+  /// If a client neither supports `documentChanges` nor
+	/// `workspace.workspaceEdit.resourceOperations` then only plain `TextEdit`s
+	/// using the `changes` property are supported.
+  std::optional<std::vector<TextDocumentEdit>> documentChanges;
 };
 bool fromJSON(const llvm::json::Value &, WorkspaceEdit &, llvm::json::Path);
 llvm::json::Value toJSON(const WorkspaceEdit &WE);