[Support] Return `LockFileManager` errors right away (#130627)

This patch removes some internal state out of `LockFileManager` by
moving the locking code from the constructor into new member function
`tryLock()` which returns the errors right away. This simplifies and
modernizes the interface.

1 files changed, 8 insertions, 9 deletions

diff --git a/clang/lib/Serialization/GlobalModuleIndex.cpp b/clang/lib/Serialization/GlobalModuleIndex.cpp
index 4b920fc..1e2272c 100644
--- a/clang/lib/Serialization/GlobalModuleIndex.cpp
+++ b/clang/lib/Serialization/GlobalModuleIndex.cpp
@@ -849,22 +849,21 @@ GlobalModuleIndex::writeIndex(FileManager &FileMgr,
 
   // Coordinate building the global index file with other processes that might
   // try to do the same.
-  llvm::LockFileManager Locked(IndexPath);
-  switch (Locked) {
-  case llvm::LockFileManager::LFS_Error:
+  llvm::LockFileManager Lock(IndexPath);
+  bool Owned;
+  if (llvm::Error Err = Lock.tryLock().moveInto(Owned)) {
+    llvm::consumeError(std::move(Err));
     return llvm::createStringError(std::errc::io_error, "LFS error");
-
-  case llvm::LockFileManager::LFS_Owned:
-    // We're responsible for building the index ourselves. Do so below.
-    break;
-
-  case llvm::LockFileManager::LFS_Shared:
+  }
+  if (!Owned) {
     // Someone else is responsible for building the index. We don't care
     // when they finish, so we're done.
     return llvm::createStringError(std::errc::device_or_resource_busy,
                                    "someone else is building the index");
   }
 
+  // We're responsible for building the index ourselves.
+
   // The module index builder.
   GlobalModuleIndexBuilder Builder(FileMgr, PCHContainerRdr);