[clangd] Store index in '.clangd/index' instead of '.clangd-index'

[ilya-biryukov]

Summary

To take up the .clangd folder for other potential uses in the future.

[kadircet]

Thanks!

clang-tools-extra/clangd/index/BackgroundIndexStorage.cpp

75

NIT: it looks like we don't need the "/" at the end of "index/"

[ilya-biryukov]

• Remove trailing slash from the path

[ilya-biryukov]

clang-tools-extra/clangd/index/BackgroundIndexStorage.cpp

75

Done.
I was not sure if it is important or not. Everything appears to work without it, so removing it now.

[ilya-biryukov]

• Update .gitignore

clang-tools-extra/clangd/index/Background.h

public:
 
   // The factory provides storage for each CDB.
   // It keeps ownership of the storage instances, and should manage caching
   // itself. Factory must be threadsafe and never returns nullptr.
   using Factory =
       llvm::unique_function<BackgroundIndexStorage *(llvm::StringRef)>;
 
   // Creates an Index Storage that saves shards into disk. Index storage uses
-  // CDBDirectory + ".clangd-index/" as the folder to save shards.
+  // CDBDirectory + ".clangd/index/" as the folder to save shards.
   static Factory createDiskBackedStorageFactory();
 };
 
 // Builds an in-memory index by by running the static indexer action over
 // all commands in a compilation database. Indexing happens in the background.
 // FIXME: it should also persist its state on disk for fast start.
 // FIXME: it should watch for changes to files on disk.
 class BackgroundIndex : public SwapIndex {

clang-tools-extra/clangd/index/BackgroundIndexStorage.cpp

if (EC)
     return llvm::errorCodeToError(EC);
   // If everything went well, we already moved the file to another name. So
   // don't delete the file, as the name might be taken by another file.
   RemoveOnFail.release();
   return llvm::ErrorSuccess();
 }
 
 // Uses disk as a storage for index shards. Creates a directory called
-// ".clangd-index/" under the path provided during construction.
+// ".clangd/index/" under the path provided during construction.
 class DiskBackedIndexStorage : public BackgroundIndexStorage {
   std::string DiskShardRoot;
 
 public:
-  // Sets DiskShardRoot to (Directory + ".clangd-index/") which is the base
+  // Sets DiskShardRoot to (Directory + ".clangd/index/") which is the base
   // directory for all shard files.
   DiskBackedIndexStorage(llvm::StringRef Directory) {
     llvm::SmallString<128> CDBDirectory(Directory);
-    llvm::sys::path::append(CDBDirectory, ".clangd-index/");
+    llvm::sys::path::append(CDBDirectory, ".clangd", "index");
     DiskShardRoot = CDBDirectory.str();
     std::error_code OK;
-    std::error_code EC = llvm::sys::fs::create_directory(DiskShardRoot);
+    std::error_code EC = llvm::sys::fs::create_directories(DiskShardRoot);
     if (EC != OK) {
       elog("Failed to create directory {0} for index storage: {1}",
            DiskShardRoot, EC.message());
     }
   }
 
   std::unique_ptr<IndexFileIn>
   loadShard(llvm::StringRef ShardIdentifier) const override {

clang-tools-extra/test/clangd/background-index.test

 # We need to splice paths into file:// URIs for this test.
 # UNSUPPORTED: win32
 
 # Use a copy of inputs, as we'll mutate it (as will the background index).
 # RUN: rm -rf %t
 # RUN: cp -r %S/Inputs/background-index %t
 # Need to embed the correct temp path in the actual JSON-RPC requests.
 # RUN: sed -i -e "s|DIRECTORY|%t|" %t/*
 
 # We're editing bar.cpp, which includes foo.h.
 # foo() is declared in foo.h and defined in foo.cpp.
 # The background index should allow us to go-to-definition on foo().
 # RUN: clangd -background-index -background-index-rebuild-period=0 -lit-test < %t/definition.jsonrpc | FileCheck %t/definition.jsonrpc
 
 # Test that the index is writing files in the expected location.
-# RUN: ls %t/.clangd-index/foo.cpp.*.idx
+# RUN: ls %t/.clangd/index/foo.cpp.*.idx
 
 # Test the index is read from disk: delete code and restart clangd.
 # RUN: rm %t/foo.cpp
 # RUN: clangd -background-index -lit-test < %t/definition.jsonrpc | FileCheck %t/definition.jsonrpc