[PATCH] D47060: [VFS] Implement getRealPath for OverlayFileSystem.

[Eric Liu via Phabricator via cfe-commits]

ioeric created this revision.
ioeric added a reviewer: bkramer.
Herald added a subscriber: cfe-commits.

Repository:
  rC Clang

https://reviews.llvm.org/D47060

Files:
  include/clang/Basic/VirtualFileSystem.h
  lib/Basic/VirtualFileSystem.cpp
  unittests/Basic/VirtualFileSystemTest.cpp


Index: unittests/Basic/VirtualFileSystemTest.cpp
===================================================================
--- unittests/Basic/VirtualFileSystemTest.cpp
+++ unittests/Basic/VirtualFileSystemTest.cpp
@@ -67,6 +67,20 @@
   std::error_code setCurrentWorkingDirectory(const Twine &Path) override {
     return std::error_code();
   }
+  // Map any symlink to "/symlink".
+  std::error_code getRealPath(const Twine &Path,
+                              SmallVectorImpl<char> &Output) const override {
+    auto I = FilesAndDirs.find(Path.str());
+    if (I == FilesAndDirs.end())
+      return make_error_code(llvm::errc::no_such_file_or_directory);
+    if (I->second.isSymlink()) {
+      StringRef SymlinkPath("/symlink");
+      Output.assign(SymlinkPath.begin(), SymlinkPath.end());
+      return std::error_code();
+    }
+    Path.toVector(Output);
+    return std::error_code();
+  }
 
   struct DirIterImpl : public clang::vfs::detail::DirIterImpl {
     std::map<std::string, vfs::Status> &FilesAndDirs;
@@ -196,6 +210,35 @@
   EXPECT_TRUE(Status->equivalent(*Status2));
 }
 
+TEST(VirtualFileSystemTest, GetRealPathInOverlay) {
+  IntrusiveRefCntPtr<DummyFileSystem> Lower(new DummyFileSystem());
+  Lower->addRegularFile("/foo");
+  Lower->addSymlink("/lower_link");
+  IntrusiveRefCntPtr<DummyFileSystem> Upper(new DummyFileSystem());
+
+  IntrusiveRefCntPtr<vfs::OverlayFileSystem> O(
+      new vfs::OverlayFileSystem(Lower));
+  O->pushOverlay(Upper);
+
+  // Regular file.
+  SmallString<16> RealPath;
+  EXPECT_FALSE(O->getRealPath("/foo", RealPath));
+  EXPECT_EQ(RealPath.str(), "/foo");
+
+  // Expect no error getting real path for symlink in lower overlay.
+  EXPECT_FALSE(O->getRealPath("/lower_link", RealPath));
+  EXPECT_EQ(RealPath.str(), "/symlink");
+
+  // Try a non-existing link.
+  EXPECT_EQ(O->getRealPath("/upper_link", RealPath),
+            errc::no_such_file_or_directory);
+
+  // Add a new symlink in upper.
+  Upper->addSymlink("/upper_link");
+  EXPECT_FALSE(O->getRealPath("/upper_link", RealPath));
+  EXPECT_EQ(RealPath.str(), "/symlink");
+}
+
 TEST(VirtualFileSystemTest, OverlayFiles) {
   IntrusiveRefCntPtr<DummyFileSystem> Base(new DummyFileSystem());
   IntrusiveRefCntPtr<DummyFileSystem> Middle(new DummyFileSystem());
Index: lib/Basic/VirtualFileSystem.cpp
===================================================================
--- lib/Basic/VirtualFileSystem.cpp
+++ lib/Basic/VirtualFileSystem.cpp
@@ -381,6 +381,19 @@
   return {};
 }
 
+std::error_code
+OverlayFileSystem::getRealPath(const Twine &Path,
+                               SmallVectorImpl<char> &Output) const {
+  // Not using overlays_begin/end because this method is const.
+  for (auto I = FSList.rbegin(), E = FSList.rend(); I != E; ++I) {
+    auto &FS = *I;
+    if (!FS->exists(Path))
+        continue;
+    return FS->getRealPath(Path, Output);
+  }
+  return errc::no_such_file_or_directory;
+}
+
 clang::vfs::detail::DirIterImpl::~DirIterImpl() = default;
 
 namespace {
Index: include/clang/Basic/VirtualFileSystem.h
===================================================================
--- include/clang/Basic/VirtualFileSystem.h
+++ include/clang/Basic/VirtualFileSystem.h
@@ -304,6 +304,8 @@
   directory_iterator dir_begin(const Twine &Dir, std::error_code &EC) override;
   llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override;
   std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
+  std::error_code getRealPath(const Twine &Path,
+                              SmallVectorImpl<char> &Output) const override;
 
   using iterator = FileSystemList::reverse_iterator;
   


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