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, 17 insertions, 14 deletions

diff --git a/clang-tools-extra/clangd/FS.cpp b/clang-tools-extra/clangd/FS.cpp
index fa94b967214..5f5dd5c64a5 100644
--- a/clang-tools-extra/clangd/FS.cpp
+++ b/clang-tools-extra/clangd/FS.cpp
@@ -8,7 +8,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "FS.h"
-#include "clang/Basic/VirtualFileSystem.h"
+#include "clang/Basic/LLVM.h"
 #include "llvm/ADT/None.h"
 #include "llvm/Support/Path.h"
 
@@ -20,7 +20,8 @@ PreambleFileStatusCache::PreambleFileStatusCache(llvm::StringRef MainFilePath)
   assert(llvm::sys::path::is_absolute(MainFilePath));
 }
 
-void PreambleFileStatusCache::update(const vfs::FileSystem &FS, vfs::Status S) {
+void PreambleFileStatusCache::update(const llvm::vfs::FileSystem &FS,
+                                     llvm::vfs::Status S) {
   SmallString<32> PathStore(S.getName());
   if (FS.makeAbsolute(PathStore))
     return;
@@ -31,7 +32,7 @@ void PreambleFileStatusCache::update(const vfs::FileSystem &FS, vfs::Status S) {
   StatCache.insert({PathStore, std::move(S)});
 }
 
-llvm::Optional<vfs::Status>
+llvm::Optional<llvm::vfs::Status>
 PreambleFileStatusCache::lookup(llvm::StringRef File) const {
   auto I = StatCache.find(File);
   if (I != StatCache.end())
@@ -39,17 +40,18 @@ PreambleFileStatusCache::lookup(llvm::StringRef File) const {
   return llvm::None;
 }
 
-IntrusiveRefCntPtr<vfs::FileSystem> PreambleFileStatusCache::getProducingFS(
-    IntrusiveRefCntPtr<vfs::FileSystem> FS) {
+IntrusiveRefCntPtr<llvm::vfs::FileSystem>
+PreambleFileStatusCache::getProducingFS(
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) {
   // This invalidates old status in cache if files are re-`open()`ed or
   // re-`stat()`ed in case file status has changed during preamble build.
-  class CollectFS : public vfs::ProxyFileSystem {
+  class CollectFS : public llvm::vfs::ProxyFileSystem {
   public:
-    CollectFS(IntrusiveRefCntPtr<vfs::FileSystem> FS,
+    CollectFS(IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
               PreambleFileStatusCache &StatCache)
         : ProxyFileSystem(std::move(FS)), StatCache(StatCache) {}
 
-    llvm::ErrorOr<std::unique_ptr<vfs::File>>
+    llvm::ErrorOr<std::unique_ptr<llvm::vfs::File>>
     openFileForRead(const Twine &Path) override {
       auto File = getUnderlyingFS().openFileForRead(Path);
       if (!File || !*File)
@@ -64,7 +66,7 @@ IntrusiveRefCntPtr<vfs::FileSystem> PreambleFileStatusCache::getProducingFS(
       return File;
     }
 
-    llvm::ErrorOr<vfs::Status> status(const Twine &Path) override {
+    llvm::ErrorOr<llvm::vfs::Status> status(const Twine &Path) override {
       auto S = getUnderlyingFS().status(Path);
       if (S)
         StatCache.update(getUnderlyingFS(), *S);
@@ -77,15 +79,16 @@ IntrusiveRefCntPtr<vfs::FileSystem> PreambleFileStatusCache::getProducingFS(
   return IntrusiveRefCntPtr<CollectFS>(new CollectFS(std::move(FS), *this));
 }
 
-IntrusiveRefCntPtr<vfs::FileSystem> PreambleFileStatusCache::getConsumingFS(
-    IntrusiveRefCntPtr<vfs::FileSystem> FS) const {
-  class CacheVFS : public vfs::ProxyFileSystem {
+IntrusiveRefCntPtr<llvm::vfs::FileSystem>
+PreambleFileStatusCache::getConsumingFS(
+    IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS) const {
+  class CacheVFS : public llvm::vfs::ProxyFileSystem {
   public:
-    CacheVFS(IntrusiveRefCntPtr<vfs::FileSystem> FS,
+    CacheVFS(IntrusiveRefCntPtr<llvm::vfs::FileSystem> FS,
              const PreambleFileStatusCache &StatCache)
         : ProxyFileSystem(std::move(FS)), StatCache(StatCache) {}
 
-    llvm::ErrorOr<vfs::Status> status(const Twine &Path) override {
+    llvm::ErrorOr<llvm::vfs::Status> status(const Twine &Path) override {
       if (auto S = StatCache.lookup(Path.str()))
         return *S;
       return getUnderlyingFS().status(Path);