[clangd] Record the file being processed in a TUScheduler thread in context.

Summary:
This allows implementations like different symbol indexes to know what
the current active file is. For example, some customized index implementation
might decide to only return results for some files.

Reviewers: ilya-biryukov

Reviewed By: ilya-biryukov

Subscribers: javed.absar, MaskRay, jkorous, arphaman, cfe-commits

Differential Revision: https://reviews.llvm.org/D50446

llvm-svn: 339320

1 files changed, 17 insertions, 6 deletions

diff --git a/clang-tools-extra/clangd/TUScheduler.cpp b/clang-tools-extra/clangd/TUScheduler.cpp
index 81a75bbc21a..cae4b0911fe 100644
--- a/clang-tools-extra/clangd/TUScheduler.cpp
+++ b/clang-tools-extra/clangd/TUScheduler.cpp
@@ -63,6 +63,14 @@ namespace {
 class ASTWorker;
 }
 
+static const clang::clangd::Key<std::string> kFileBeingProcessed;
+
+llvm::Optional<llvm::StringRef> TUScheduler::getFileBeingProcessedInContext() {
+  if (auto *File = Context::current().get(kFileBeingProcessed))
+    return StringRef(*File);
+  return llvm::None;
+}
+
 /// An LRU cache of idle ASTs.
 /// Because we want to limit the overall number of these we retain, the cache
 /// owns ASTs (and may evict them) while their workers are idle.
@@ -491,8 +499,9 @@ void ASTWorker::startTask(llvm::StringRef Name,
   {
     std::lock_guard<std::mutex> Lock(Mutex);
     assert(!Done && "running a task after stop()");
-    Requests.push_back({std::move(Task), Name, steady_clock::now(),
-                        Context::current().clone(), UpdateType});
+    Requests.push_back(
+        {std::move(Task), Name, steady_clock::now(),
+         Context::current().derive(kFileBeingProcessed, FileName), UpdateType});
   }
   RequestsCV.notify_all();
 }
@@ -734,10 +743,12 @@ void TUScheduler::runWithPreamble(
     Action(InputsAndPreamble{Contents, Command, Preamble.get()});
   };
 
-  PreambleTasks->runAsync("task:" + llvm::sys::path::filename(File),
-                          Bind(Task, std::string(Name), std::string(File),
-                               It->second->Contents, It->second->Command,
-                               Context::current().clone(), std::move(Action)));
+  PreambleTasks->runAsync(
+      "task:" + llvm::sys::path::filename(File),
+      Bind(Task, std::string(Name), std::string(File), It->second->Contents,
+           It->second->Command,
+           Context::current().derive(kFileBeingProcessed, File),
+           std::move(Action)));
 }
 
 std::vector<std::pair<Path, std::size_t>>