From 32ebed17306375785ab861a36297cd892a93c9bc Mon Sep 17 00:00:00 2001
From: Eric Liu <ioeric@google.com>
Date: Thu, 24 May 2018 11:17:00 +0000
Subject: [PATCH] [VFS] Implement getRealPath in InMemoryFileSystem.

Reviewers: bkramer

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D47262

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@333172 91177308-0d34-0410-b5e6-96231b3b80d8
---
 include/clang/Basic/VirtualFileSystem.h   |  8 ++++++++
 lib/Basic/VirtualFileSystem.cpp           | 13 +++++++++++++
 unittests/Basic/VirtualFileSystemTest.cpp | 22 ++++++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/include/clang/Basic/VirtualFileSystem.h b/include/clang/Basic/VirtualFileSystem.h
index 21daeb2afc..2480b91123 100644
--- a/include/clang/Basic/VirtualFileSystem.h
+++ b/include/clang/Basic/VirtualFileSystem.h
@@ -374,6 +374,14 @@ public:
   llvm::ErrorOr<std::string> getCurrentWorkingDirectory() const override {
     return WorkingDirectory;
   }
+  /// Canonicalizes \p Path by combining with the current working
+  /// directory and normalizing the path (e.g. remove dots). If the current
+  /// working directory is not set, this returns errc::operation_not_permitted.
+  ///
+  /// This doesn't resolve symlinks as they are not supported in in-memory file
+  /// system.
+  std::error_code getRealPath(const Twine &Path,
+                              SmallVectorImpl<char> &Output) const override;
 
   std::error_code setCurrentWorkingDirectory(const Twine &Path) override;
 };
diff --git a/lib/Basic/VirtualFileSystem.cpp b/lib/Basic/VirtualFileSystem.cpp
index b2eb5b9abf..234adcd9aa 100644
--- a/lib/Basic/VirtualFileSystem.cpp
+++ b/lib/Basic/VirtualFileSystem.cpp
@@ -788,6 +788,19 @@ std::error_code InMemoryFileSystem::setCurrentWorkingDirectory(const Twine &P) {
   return {};
 }
 
+std::error_code
+InMemoryFileSystem::getRealPath(const Twine &Path,
+                                SmallVectorImpl<char> &Output) const {
+  auto CWD = getCurrentWorkingDirectory();
+  if (!CWD || CWD->empty())
+    return errc::operation_not_permitted;
+  Path.toVector(Output);
+  if (auto EC = makeAbsolute(Output))
+    return EC;
+  llvm::sys::path::remove_dots(Output, /*remove_dot_dot=*/true);
+  return {};
+}
+
 } // namespace vfs
 } // namespace clang
 
diff --git a/unittests/Basic/VirtualFileSystemTest.cpp b/unittests/Basic/VirtualFileSystemTest.cpp
index 673eca88d6..e510c3e2e3 100644
--- a/unittests/Basic/VirtualFileSystemTest.cpp
+++ b/unittests/Basic/VirtualFileSystemTest.cpp
@@ -813,6 +813,28 @@ TEST_F(InMemoryFileSystemTest, WorkingDirectory) {
                       NormalizedFS.getCurrentWorkingDirectory().get()));
 }
 
+TEST_F(InMemoryFileSystemTest, GetRealPath) {
+  SmallString<16> Path;
+  EXPECT_EQ(FS.getRealPath("b", Path), errc::operation_not_permitted);
+
+  auto GetRealPath = [this](StringRef P) {
+    SmallString<16> Output;
+    auto EC = FS.getRealPath(P, Output);
+    EXPECT_FALSE(EC);
+    return Output.str().str();
+  };
+
+  FS.setCurrentWorkingDirectory("a");
+  EXPECT_EQ(GetRealPath("b"), "a/b");
+  EXPECT_EQ(GetRealPath("../b"), "b");
+  EXPECT_EQ(GetRealPath("b/./c"), "a/b/c");
+
+  FS.setCurrentWorkingDirectory("/a");
+  EXPECT_EQ(GetRealPath("b"), "/a/b");
+  EXPECT_EQ(GetRealPath("../b"), "/b");
+  EXPECT_EQ(GetRealPath("b/./c"), "/a/b/c");
+}
+
 TEST_F(InMemoryFileSystemTest, AddFileWithUser) {
   FS.addFile("/a/b/c", 0, MemoryBuffer::getMemBuffer("abc"), 0xFEEDFACE);
   auto Stat = FS.status("/a");
-- 
2.40.0