Add llvm::sys::fs::real_path.

LLVM already has real_path like functionality, but it is
cumbersome to use and involves clean up after (e.g. you have
to call openFileForRead, then close the resulting FD).

Furthermore, on Windows it doesn't work for directories since
opening a directory and opening a file require slightly
different flags.

So I add a simple function `real_path` which works for all
paths on all platforms and has a simple to use interface.

In doing so, I add the ability to opt in to resolving tilde
expressions (e.g. ~/foo), which are normally handled by
the shell.

Differential Revision: https://reviews.llvm.org/D30668

llvm-svn: 297483

1 files changed, 36 insertions, 0 deletions

diff --git a/llvm/unittests/Support/Path.cpp b/llvm/unittests/Support/Path.cpp
index 3ad7e70abf4..571edaafbb6 100644
--- a/llvm/unittests/Support/Path.cpp
+++ b/llvm/unittests/Support/Path.cpp
@@ -499,6 +499,42 @@ TEST_F(FileSystemTest, Unique) {
   ASSERT_NO_ERROR(fs::remove(TempPath));
 }
 
+TEST_F(FileSystemTest, RealPath) {
+  ASSERT_NO_ERROR(
+      fs::create_directories(Twine(TestDirectory) + "/test1/test2/test3"));
+  ASSERT_TRUE(fs::exists(Twine(TestDirectory) + "/test1/test2/test3"));
+
+  SmallString<64> RealBase;
+  SmallString<64> Expected;
+  SmallString<64> Actual;
+
+  // TestDirectory itself might be under a symlink or have been specified with
+  // a different case than the existing temp directory.  In such cases real_path
+  // on the concatenated path will differ in the TestDirectory portion from
+  // how we specified it.  Make sure to compare against the real_path of the
+  // TestDirectory, and not just the value of TestDirectory.
+  ASSERT_NO_ERROR(fs::real_path(TestDirectory, RealBase));
+  path::native(Twine(RealBase) + "/test1/test2", Expected);
+
+  ASSERT_NO_ERROR(fs::real_path(
+      Twine(TestDirectory) + "/././test1/../test1/test2/./test3/..", Actual));
+
+  EXPECT_EQ(Expected, Actual);
+
+  SmallString<64> HomeDir;
+  ASSERT_TRUE(llvm::sys::path::home_directory(HomeDir));
+  ASSERT_NO_ERROR(fs::real_path(HomeDir, Expected));
+  ASSERT_NO_ERROR(fs::real_path("~", Actual, true));
+  EXPECT_EQ(Expected, Actual);
+  ASSERT_NO_ERROR(fs::real_path("~/", Actual, true));
+  EXPECT_EQ(Expected, Actual);
+
+  fs::real_path(Twine(TestDirectory) + "/does_not_exist", Actual);
+  EXPECT_EQ("", Actual);
+
+  ASSERT_NO_ERROR(fs::remove_directories(Twine(TestDirectory) + "/test1"));
+}
+
 TEST_F(FileSystemTest, TempFiles) {
   // Create a temp file.
   int FileDescriptor;