Lift VFS from clang to llvm (NFC)

This patch moves the virtual file system form clang to llvm so it can be
used by more projects.

Concretely the patch:
 - Moves VirtualFileSystem.{h|cpp} from clang/Basic to llvm/Support.
 - Moves the corresponding unit test from clang to llvm.
 - Moves the vfs namespace from clang::vfs to llvm::vfs.
 - Formats the lines affected by this change, mostly this is the result of
   the added llvm namespace.

RFC on the mailing list:
http://lists.llvm.org/pipermail/llvm-dev/2018-October/126657.html

Differential revision: https://reviews.llvm.org/D52783

llvm-svn: 344140

1 files changed, 9 insertions, 7 deletions

diff --git a/clang/lib/Basic/FileSystemStatCache.cpp b/clang/lib/Basic/FileSystemStatCache.cpp
index f5856cb..9a515e8 100644
--- a/clang/lib/Basic/FileSystemStatCache.cpp
+++ b/clang/lib/Basic/FileSystemStatCache.cpp
@@ -12,17 +12,17 @@
 //===----------------------------------------------------------------------===//
 
 #include "clang/Basic/FileSystemStatCache.h"
-#include "clang/Basic/VirtualFileSystem.h"
 #include "llvm/Support/Chrono.h"
 #include "llvm/Support/ErrorOr.h"
 #include "llvm/Support/Path.h"
+#include "llvm/Support/VirtualFileSystem.h"
 #include <utility>
 
 using namespace clang;
 
 void FileSystemStatCache::anchor() {}
 
-static void copyStatusToFileData(const vfs::Status &Status,
+static void copyStatusToFileData(const llvm::vfs::Status &Status,
                                  FileData &Data) {
   Data.Name = Status.getName();
   Data.Size = Status.getSize();
@@ -44,8 +44,9 @@ static void copyStatusToFileData(const vfs::Status &Status,
 /// implementation can optionally fill in FileDescriptor with a valid
 /// descriptor and the client guarantees that it will close it.
 bool FileSystemStatCache::get(StringRef Path, FileData &Data, bool isFile,
-                              std::unique_ptr<vfs::File> *F,
-                              FileSystemStatCache *Cache, vfs::FileSystem &FS) {
+                              std::unique_ptr<llvm::vfs::File> *F,
+                              FileSystemStatCache *Cache,
+                              llvm::vfs::FileSystem &FS) {
   LookupResult R;
   bool isForDir = !isFile;
 
@@ -55,7 +56,7 @@ bool FileSystemStatCache::get(StringRef Path, FileData &Data, bool isFile,
   else if (isForDir || !F) {
     // If this is a directory or a file descriptor is not needed and we have
     // no cache, just go to the file system.
-    llvm::ErrorOr<vfs::Status> Status = FS.status(Path);
+    llvm::ErrorOr<llvm::vfs::Status> Status = FS.status(Path);
     if (!Status) {
       R = CacheMissing;
     } else {
@@ -79,7 +80,7 @@ bool FileSystemStatCache::get(StringRef Path, FileData &Data, bool isFile,
       // Otherwise, the open succeeded.  Do an fstat to get the information
       // about the file.  We'll end up returning the open file descriptor to the
       // client to do what they please with it.
-      llvm::ErrorOr<vfs::Status> Status = (*OwnedFile)->status();
+      llvm::ErrorOr<llvm::vfs::Status> Status = (*OwnedFile)->status();
       if (Status) {
         R = CacheExists;
         copyStatusToFileData(*Status, Data);
@@ -111,7 +112,8 @@ bool FileSystemStatCache::get(StringRef Path, FileData &Data, bool isFile,
 
 MemorizeStatCalls::LookupResult
 MemorizeStatCalls::getStat(StringRef Path, FileData &Data, bool isFile,
-                           std::unique_ptr<vfs::File> *F, vfs::FileSystem &FS) {
+                           std::unique_ptr<llvm::vfs::File> *F,
+                           llvm::vfs::FileSystem &FS) {
   LookupResult Result = statChained(Path, Data, isFile, F, FS);
 
   // Do not cache failed stats, it is easy to construct common inconsistent