Revert r263617, "Reapply: [VFS] Add support for handling path traversals"

It broke standalone clang build.

llvm-svn: 263636

clang/lib/Basic/VirtualFileSystem.cpp

@@ -112,20 +112,6 @@ bool FileSystem::exists(const Twine &Path) {
   return Status && Status->exists();
 }
 
-#ifndef NDEBUG
-static bool isTraversalComponent(StringRef Component) {
-  return Component.equals("..") || Component.equals(".");
-}
-
-static bool pathHasTraversal(StringRef Path) {
-  using namespace llvm::sys;
-  for (StringRef Comp : llvm::make_range(path::begin(Path), path::end(Path)))
-    if (isTraversalComponent(Comp))
-      return true;
-  return false;
-}
-#endif
-
 //===-----------------------------------------------------------------------===/
 // RealFileSystem implementation
 //===-----------------------------------------------------------------------===/
@@ -833,16 +819,6 @@ class RedirectingFileSystem : public vfs::FileSystem {
   bool UseExternalNames;
   /// @}
 
-  /// Virtual file paths and external files could be canonicalized without "..",
-  /// "." and "./" in their paths. FIXME: some unittests currently fail on
-  /// win32 when using remove_dots and remove_leading_dotslash on paths.
-  bool UseCanonicalizedPaths =
-#ifdef LLVM_ON_WIN32
-      false;
-#else
-      true;
-#endif
-
   friend class RedirectingFileSystemParser;
 
 private:
@@ -978,7 +954,7 @@ class RedirectingFileSystemParser {
     return true;
   }
 
-  std::unique_ptr<Entry> parseEntry(yaml::Node *N, RedirectingFileSystem *FS) {
+  std::unique_ptr<Entry> parseEntry(yaml::Node *N) {
     yaml::MappingNode *M = dyn_cast<yaml::MappingNode>(N);
     if (!M) {
       error(N, "expected mapping node for file or directory entry");
@@ -1018,17 +994,7 @@ class RedirectingFileSystemParser {
       if (Key == "name") {
         if (!parseScalarString(I->getValue(), Value, Buffer))
           return nullptr;
-
-        if (FS->UseCanonicalizedPaths) {
-          SmallString<256> Path(Value);
-          // Guarantee that old YAML files containing paths with ".." and "."
-          // are properly canonicalized before read into the VFS.
-          Path = sys::path::remove_leading_dotslash(Path);
-          sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
-          Name = Path.str();
-        } else {
-          Name = Value;
-        }
+        Name = Value;
       } else if (Key == "type") {
         if (!parseScalarString(I->getValue(), Value, Buffer))
           return nullptr;
@@ -1058,7 +1024,7 @@ class RedirectingFileSystemParser {
         for (yaml::SequenceNode::iterator I = Contents->begin(),
                                           E = Contents->end();
              I != E; ++I) {
-          if (std::unique_ptr<Entry> E = parseEntry(&*I, FS))
+          if (std::unique_ptr<Entry> E = parseEntry(&*I))
             EntryArrayContents.push_back(std::move(E));
           else
             return nullptr;
@@ -1072,16 +1038,7 @@ class RedirectingFileSystemParser {
         HasContents = true;
         if (!parseScalarString(I->getValue(), Value, Buffer))
           return nullptr;
-        if (FS->UseCanonicalizedPaths) {
-          SmallString<256> Path(Value);
-          // Guarantee that old YAML files containing paths with ".." and "."
-          // are properly canonicalized before read into the VFS.
-          Path = sys::path::remove_leading_dotslash(Path);
-          sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
-          ExternalContentsPath = Path.str();
-        } else {
-          ExternalContentsPath = Value;
-        }
+        ExternalContentsPath = Value;
       } else if (Key == "use-external-name") {
         bool Val;
         if (!parseScalarBool(I->getValue(), Val))
@@ -1192,7 +1149,7 @@ public:
 
         for (yaml::SequenceNode::iterator I = Roots->begin(), E = Roots->end();
              I != E; ++I) {
-          if (std::unique_ptr<Entry> E = parseEntry(&*I, FS))
+          if (std::unique_ptr<Entry> E = parseEntry(&*I))
             FS->Roots.push_back(std::move(E));
           else
             return false;
@@ -1271,14 +1228,6 @@ ErrorOr<Entry *> RedirectingFileSystem::lookupPath(const Twine &Path_) {
   if (std::error_code EC = makeAbsolute(Path))
     return EC;
 
-  // Canonicalize path by removing ".", "..", "./", etc components. This is
-  // a VFS request, do bot bother about symlinks in the path components
-  // but canonicalize in order to perform the correct entry search.
-  if (UseCanonicalizedPaths) {
-    Path = sys::path::remove_leading_dotslash(Path);
-    sys::path::remove_dots(Path, /*remove_dot_dot=*/true);
-  }
-
   if (Path.empty())
     return make_error_code(llvm::errc::invalid_argument);
 
@@ -1295,17 +1244,10 @@ ErrorOr<Entry *> RedirectingFileSystem::lookupPath(const Twine &Path_) {
 ErrorOr<Entry *>
 RedirectingFileSystem::lookupPath(sys::path::const_iterator Start,
                                   sys::path::const_iterator End, Entry *From) {
-#ifndef LLVM_ON_WIN32
-  assert(!isTraversalComponent(*Start) &&
-         !isTraversalComponent(From->getName()) &&
-         "Paths should not contain traversal components");
-#else
-  // FIXME: this is here to support windows, remove it once canonicalized
-  // paths become globally default.
   if (Start->equals("."))
     ++Start;
-#endif
 
+  // FIXME: handle ..
   if (CaseSensitive ? !Start->equals(From->getName())
                     : !Start->equals_lower(From->getName()))
     // failure to match
@@ -1424,6 +1366,16 @@ UniqueID vfs::getNextVirtualUniqueID() {
   return UniqueID(std::numeric_limits<uint64_t>::max(), ID);
 }
 
+#ifndef NDEBUG
+static bool pathHasTraversal(StringRef Path) {
+  using namespace llvm::sys;
+  for (StringRef Comp : llvm::make_range(path::begin(Path), path::end(Path)))
+    if (Comp == "." || Comp == "..")
+      return true;
+  return false;
+}
+#endif
+
 void YAMLVFSWriter::addFileMapping(StringRef VirtualPath, StringRef RealPath) {
   assert(sys::path::is_absolute(VirtualPath) && "virtual path not absolute");
   assert(sys::path::is_absolute(RealPath) && "real path not absolute");