[clang-format] Flexible line endings

Line ending detection is now set with the `DeriveLineEnding` option.
CRLF can now be used as the default line ending by setting `UseCRLF`.
When line ending detection is disabled, all line endings are converted
according to the `UseCRLF` option.

Differential Revision: https://reviews.llvm.org/D19031

1 files changed, 12 insertions, 3 deletions

diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 60958597ad2..083c3a8f02f 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -467,6 +467,7 @@ template <> struct MappingTraits<FormatStyle> {
                    Style.ConstructorInitializerIndentWidth);
     IO.mapOptional("ContinuationIndentWidth", Style.ContinuationIndentWidth);
     IO.mapOptional("Cpp11BracedListStyle", Style.Cpp11BracedListStyle);
+    IO.mapOptional("DeriveLineEnding", Style.DeriveLineEnding);
     IO.mapOptional("DerivePointerAlignment", Style.DerivePointerAlignment);
     IO.mapOptional("DisableFormat", Style.DisableFormat);
     IO.mapOptional("ExperimentalAutoDetectBinPacking",
@@ -546,6 +547,7 @@ template <> struct MappingTraits<FormatStyle> {
     IO.mapOptional("StatementMacros", Style.StatementMacros);
     IO.mapOptional("TabWidth", Style.TabWidth);
     IO.mapOptional("TypenameMacros", Style.TypenameMacros);
+    IO.mapOptional("UseCRLF", Style.UseCRLF);
     IO.mapOptional("UseTab", Style.UseTab);
   }
 };
@@ -762,6 +764,7 @@ FormatStyle getLLVMStyle(FormatStyle::LanguageKind Language) {
   LLVMStyle.ConstructorInitializerIndentWidth = 4;
   LLVMStyle.ContinuationIndentWidth = 4;
   LLVMStyle.Cpp11BracedListStyle = true;
+  LLVMStyle.DeriveLineEnding = true;
   LLVMStyle.DerivePointerAlignment = false;
   LLVMStyle.ExperimentalAutoDetectBinPacking = false;
   LLVMStyle.FixNamespaceComments = true;
@@ -792,6 +795,7 @@ FormatStyle getLLVMStyle(FormatStyle::LanguageKind Language) {
   LLVMStyle.PointerAlignment = FormatStyle::PAS_Right;
   LLVMStyle.SpacesBeforeTrailingComments = 1;
   LLVMStyle.Standard = FormatStyle::LS_Latest;
+  LLVMStyle.UseCRLF = false;
   LLVMStyle.UseTab = FormatStyle::UT_Never;
   LLVMStyle.ReflowComments = true;
   LLVMStyle.SpacesInParentheses = false;
@@ -1350,7 +1354,10 @@ public:
 
     WhitespaceManager Whitespaces(
         Env.getSourceManager(), Style,
-        inputUsesCRLF(Env.getSourceManager().getBufferData(Env.getFileID())));
+        Style.DeriveLineEnding ?
+          inputUsesCRLF(Env.getSourceManager().getBufferData(Env.getFileID()),
+                        Style.UseCRLF) :
+          Style.UseCRLF);
     ContinuationIndenter Indenter(Style, Tokens.getKeywords(),
                                   Env.getSourceManager(), Whitespaces, Encoding,
                                   BinPackInconclusiveFunctions);
@@ -1371,8 +1378,10 @@ public:
   }
 
 private:
-  static bool inputUsesCRLF(StringRef Text) {
-    return Text.count('\r') * 2 > Text.count('\n');
+  static bool inputUsesCRLF(StringRef Text, bool DefaultToCRLF) {
+    size_t LF = Text.count('\n');
+    size_t CR = Text.count('\r') * 2;
+    return LF == CR ? DefaultToCRLF : CR > LF;
   }
 
   bool