[ADT] [NFC] Add StringRef::detectEOL

This change moves EOL detection out of the clang::InclusionRewriter into
llvm::StringRef so that it can be easily reused elsewhere. It also adds
additional explicit test cases to verify the correct and expected return
results.

Reviewed By: dblaikie

Differential Revision: https://reviews.llvm.org/D117626

1 files changed, 30 insertions, 0 deletions

diff --git a/llvm/unittests/ADT/StringRefTest.cpp b/llvm/unittests/ADT/StringRefTest.cpp
index 41c3580..e80a25a 100644
--- a/llvm/unittests/ADT/StringRefTest.cpp
+++ b/llvm/unittests/ADT/StringRefTest.cpp
@@ -1109,6 +1109,36 @@ TEST(StringRefTest, GTestPrinter) {
   EXPECT_EQ(R"("foo")", ::testing::PrintToString(StringRef("foo")));
 }
 
+TEST(StringRefTest, LFLineEnding) {
+  constexpr StringRef Cases[] = {"\nDoggo\nPupper", "Floofer\n", "Woofer"};
+  EXPECT_EQ(StringRef("\n"), Cases[0].detectEOL());
+  EXPECT_EQ(StringRef("\n"), Cases[1].detectEOL());
+  EXPECT_EQ(StringRef("\n"), Cases[2].detectEOL());
+}
+
+TEST(StringRefTest, CRLineEnding) {
+  constexpr StringRef Cases[] = {"\rDoggo\rPupper", "Floofer\r", "Woo\rfer\n"};
+  EXPECT_EQ(StringRef("\r"), Cases[0].detectEOL());
+  EXPECT_EQ(StringRef("\r"), Cases[1].detectEOL());
+  EXPECT_EQ(StringRef("\r"), Cases[2].detectEOL());
+}
+
+TEST(StringRefTest, CRLFLineEnding) {
+  constexpr StringRef Cases[] = {"\r\nDoggo\r\nPupper", "Floofer\r\n",
+                                 "Woofer\r\nSubWoofer\n"};
+  EXPECT_EQ(StringRef("\r\n"), Cases[0].detectEOL());
+  EXPECT_EQ(StringRef("\r\n"), Cases[1].detectEOL());
+  EXPECT_EQ(StringRef("\r\n"), Cases[2].detectEOL());
+}
+
+TEST(StringRefTest, LFCRLineEnding) {
+  constexpr StringRef Cases[] = {"\n\rDoggo\n\rPupper", "Floofer\n\r",
+                                 "Woofer\n\rSubWoofer\n"};
+  EXPECT_EQ(StringRef("\n\r"), Cases[0].detectEOL());
+  EXPECT_EQ(StringRef("\n\r"), Cases[1].detectEOL());
+  EXPECT_EQ(StringRef("\n\r"), Cases[2].detectEOL());
+}
+
 static_assert(std::is_trivially_copyable<StringRef>::value,
               "trivially copyable");