1 files changed, 51 insertions, 0 deletions
diff --git a/clangd/GlobalCompilationDatabase.h b/clangd/GlobalCompilationDatabase.h
index cf1e613f..b64028fc 100644
--- a/clangd/GlobalCompilationDatabase.h
+++ b/clangd/GlobalCompilationDatabase.h
@@ -85,6 +85,57 @@ private:
   /// is located.
   llvm::Optional<Path> CompileCommandsDir;
 };
+
+/// A wrapper around GlobalCompilationDatabase that caches the compile commands.
+/// Note that only results of getCompileCommand are cached.
+class CachingCompilationDb : public GlobalCompilationDatabase {
+public:
+  explicit CachingCompilationDb(const GlobalCompilationDatabase &InnerCDB);
+
+  /// Gets compile command for \p File from cache or CDB if it's not in the
+  /// cache.
+  llvm::Optional<tooling::CompileCommand>
+  getCompileCommand(PathRef File) const override;
+
+  /// Forwards to the inner CDB. Results of this function are not cached.
+  tooling::CompileCommand getFallbackCommand(PathRef File) const override;
+
+  /// Removes an entry for \p File if it's present in the cache.
+  void invalidate(PathRef File);
+
+  /// Removes all cached compile commands.
+  void clear();
+
+private:
+  const GlobalCompilationDatabase &InnerCDB;
+  mutable std::mutex Mut;
+  mutable llvm::StringMap<llvm::Optional<tooling::CompileCommand>>
+      Cached; /* GUARDED_BY(Mut) */
+};
+
+/// Gets compile args from an in-memory mapping based on a filepath. Typically
+/// used by clients who provide the compile commands themselves.
+class InMemoryCompilationDb : public GlobalCompilationDatabase {
+public:
+  /// Gets compile command for \p File from the stored mapping.
+  llvm::Optional<tooling::CompileCommand>
+  getCompileCommand(PathRef File) const override;
+
+  /// Sets the compilation command for a particular file.
+  ///
+  /// \returns True if the File had no compilation command before.
+  bool setCompilationCommandForFile(PathRef File,
+                                    tooling::CompileCommand CompilationCommand);
+
+  /// Removes the compilation command for \p File if it's present in the
+  /// mapping.
+  void invalidate(PathRef File);
+
+private:
+  mutable std::mutex Mutex;
+  llvm::StringMap<tooling::CompileCommand> Commands; /* GUARDED_BY(Mut) */
+};
+
 } // namespace clangd
 } // namespace clang