[clangd] Implement typeHierarchy/resolve for subtypes

Summary:
This allows the client to resolve subtypes one level at a time.

For supertypes, this is not necessary, because we eagerly compute
supertypes and return all levels.

Reviewers: sammccall

Subscribers: ilya-biryukov, MaskRay, jkorous, arphaman, kadircet, cfe-commits

Tags: #clang

Differential Revision: https://reviews.llvm.org/D64308

llvm-svn: 365867

1 files changed, 18 insertions, 5 deletions

diff --git a/clang-tools-extra/clangd/Protocol.h b/clang-tools-extra/clangd/Protocol.h
index 7a1a8c77d25..a2c9438ea9d 100644
--- a/clang-tools-extra/clangd/Protocol.h
+++ b/clang-tools-extra/clangd/Protocol.h
@@ -1127,7 +1127,7 @@ struct TypeHierarchyItem {
   SymbolKind kind;
 
   /// `true` if the hierarchy item is deprecated. Otherwise, `false`.
-  bool deprecated;
+  bool deprecated = false;
 
   /// The URI of the text document where this type hierarchy item belongs to.
   URIForFile uri;
@@ -1153,13 +1153,26 @@ struct TypeHierarchyItem {
   /// descendants. If not defined, the children have not been resolved.
   llvm::Optional<std::vector<TypeHierarchyItem>> children;
 
-  /// The protocol has a slot here for an optional 'data' filed, which can
-  /// be used to identify a type hierarchy item in a resolve request. We don't
-  /// need this (the item itself is sufficient to identify what to resolve)
-  /// so don't declare it.
+  /// An optional 'data' filed, which can be used to identify a type hierarchy
+  /// item in a resolve request.
+  llvm::Optional<std::string> data;
 };
 llvm::json::Value toJSON(const TypeHierarchyItem &);
 llvm::raw_ostream &operator<<(llvm::raw_ostream &, const TypeHierarchyItem &);
+bool fromJSON(const llvm::json::Value &, TypeHierarchyItem &);
+
+/// Parameters for the `typeHierarchy/resolve` request.
+struct ResolveTypeHierarchyItemParams {
+  /// The item to resolve.
+  TypeHierarchyItem item;
+
+  /// The hierarchy levels to resolve. `0` indicates no level.
+  int resolve;
+
+  /// The direction of the hierarchy levels to resolve.
+  TypeHierarchyDirection direction;
+};
+bool fromJSON(const llvm::json::Value &, ResolveTypeHierarchyItemParams &);
 
 struct ReferenceParams : public TextDocumentPositionParams {
   // For now, no options like context.includeDeclaration are supported.