[PATCH] Remove extra whitespace instead of breaking the line in comments when possible.

[Alexander Kornienko]

  Added a separate method to condense whitespace instead of inserting a line break.
  Added more tests.

Hi klimek,

http://llvm-reviews.chandlerc.com/D2131

CHANGE SINCE LAST DIFF
  http://llvm-reviews.chandlerc.com/D2131?vs=5425&id=5449#toc

Files:
  lib/Format/BreakableToken.cpp
  lib/Format/BreakableToken.h
  lib/Format/ContinuationIndenter.cpp
  unittests/Format/FormatTest.cpp

Index: lib/Format/BreakableToken.cpp
===================================================================
--- lib/Format/BreakableToken.cpp
+++ lib/Format/BreakableToken.cpp
@@ -218,6 +218,14 @@
       Postfix, Prefix, InPPDirective, 1, IndentLevel, StartColumn);
 }
 
+void BreakableLineComment::replaceWhitespace(unsigned LineIndex,
+                                             unsigned TailOffset, Split Split,
+                                             WhitespaceManager &Whitespaces) {
+  Whitespaces.replaceWhitespaceInToken(Tok, OriginalPrefix.size() + TailOffset +
+                                                Split.first,
+                                       Split.second, "", "", false, 0, 0, 1);
+}
+
 void
 BreakableLineComment::replaceWhitespaceBefore(unsigned LineIndex,
                                               WhitespaceManager &Whitespaces) {
@@ -374,6 +382,18 @@
       IndentLevel, IndentAtLineBreak - Decoration.size());
 }
 
+void BreakableBlockComment::replaceWhitespace(unsigned LineIndex,
+                                              unsigned TailOffset, Split Split,
+                                              WhitespaceManager &Whitespaces) {
+  StringRef Text = Lines[LineIndex].substr(TailOffset);
+  unsigned BreakOffsetInToken =
+      Text.data() - Tok.TokenText.data() + Split.first;
+  unsigned CharsToRemove = Split.second;
+  Whitespaces.replaceWhitespaceInToken(
+      Tok, BreakOffsetInToken, CharsToRemove, "", "", /*InPPDirective=*/false,
+      /*Newlines=*/0, /*IndentLevel=*/0, /*Spaces=*/1);
+}
+
 void
 BreakableBlockComment::replaceWhitespaceBefore(unsigned LineIndex,
                                                WhitespaceManager &Whitespaces) {
Index: lib/Format/BreakableToken.h
===================================================================
--- lib/Format/BreakableToken.h
+++ lib/Format/BreakableToken.h
@@ -61,6 +61,12 @@
   virtual void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
                            WhitespaceManager &Whitespaces) = 0;
 
+  /// \brief Replaces whitespace range, described with \p Split, with a single
+  /// space character.
+  virtual void replaceWhitespace(unsigned LineIndex, unsigned TailOffset,
+                                 Split Split,
+                                 WhitespaceManager &Whitespaces) = 0;
+
   /// \brief Replaces the whitespace between \p LineIndex-1 and \p LineIndex.
   virtual void replaceWhitespaceBefore(unsigned LineIndex,
                                        WhitespaceManager &Whitespaces) {}
@@ -121,6 +127,9 @@
                          unsigned ColumnLimit) const;
   virtual void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
                            WhitespaceManager &Whitespaces);
+  virtual void replaceWhitespace(unsigned LineIndex, unsigned TailOffset,
+                                 Split Split,
+                                 WhitespaceManager &Whitespaces) {}
 };
 
 class BreakableLineComment : public BreakableSingleLineToken {
@@ -137,6 +146,9 @@
                          unsigned ColumnLimit) const;
   virtual void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
                            WhitespaceManager &Whitespaces);
+  virtual void replaceWhitespace(unsigned LineIndex, unsigned TailOffset,
+                                 Split Split,
+                                 WhitespaceManager &Whitespaces);
   virtual void replaceWhitespaceBefore(unsigned LineIndex,
                                        WhitespaceManager &Whitespaces);
 
@@ -166,6 +178,9 @@
                          unsigned ColumnLimit) const;
   virtual void insertBreak(unsigned LineIndex, unsigned TailOffset, Split Split,
                            WhitespaceManager &Whitespaces);
+  virtual void replaceWhitespace(unsigned LineIndex, unsigned TailOffset,
+                                 Split Split,
+                                 WhitespaceManager &Whitespaces);
   virtual void replaceWhitespaceBefore(unsigned LineIndex,
                                        WhitespaceManager &Whitespaces);
 
Index: lib/Format/ContinuationIndenter.cpp
===================================================================
--- lib/Format/ContinuationIndenter.cpp
+++ lib/Format/ContinuationIndenter.cpp
@@ -811,6 +811,15 @@
       assert(Split.first != 0);
       unsigned NewRemainingTokenColumns = Token->getLineLengthAfterSplit(
           LineIndex, TailOffset + Split.first + Split.second, StringRef::npos);
+
+      // We can remove extra whitespace instead of breaking the line.
+      if (RemainingTokenColumns + 1 - Split.second <= RemainingSpace) {
+        RemainingTokenColumns = 0;
+        if (!DryRun)
+          Token->replaceWhitespace(LineIndex, TailOffset, Split, Whitespaces);
+        break;
+      }
+
       assert(NewRemainingTokenColumns < RemainingTokenColumns);
       if (!DryRun)
         Token->insertBreak(LineIndex, TailOffset, Split, Whitespaces);
Index: unittests/Format/FormatTest.cpp
===================================================================
--- unittests/Format/FormatTest.cpp
+++ unittests/Format/FormatTest.cpp
@@ -985,6 +985,11 @@
             format("//Even if it makes the line exceed the column limit",
                    getLLVMStyleWithColumns(51)));
   EXPECT_EQ("//--But not here", format("//--But not here", getLLVMStyle()));
+
+  EXPECT_EQ("// aa bb cc dd",
+            format("// aa bb             cc dd                   ",
+                   getLLVMStyleWithColumns(15)));
+
   EXPECT_EQ("// A comment before\n"
             "// a macro\n"
             "// definition\n"
@@ -1244,6 +1249,17 @@
                    "      \n"
                    "               \n"
                    "      */\n"));
+
+  EXPECT_EQ("/* a a */",
+            format("/* a a            */", getLLVMStyleWithColumns(15)));
+  EXPECT_EQ("/* a a bc  */",
+            format("/* a a            bc  */", getLLVMStyleWithColumns(15)));
+  EXPECT_EQ("/* aaa aaa\n"
+            " * aaaaa */",
+            format("/* aaa aaa aaaaa       */", getLLVMStyleWithColumns(15)));
+  EXPECT_EQ("/* aaa aaa\n"
+            " * aaaaa     */",
+            format("/* aaa aaa aaaaa     */", getLLVMStyleWithColumns(15)));
 }
 
 TEST_F(FormatTest, SplitsLongLinesInCommentsInPreprocessor) {
-------------- next part --------------
A non-text attachment was scrubbed...
Name: D2131.2.patch
Type: text/x-patch
Size: 6338 bytes
Desc: not available
URL: <http://lists.llvm.org/pipermail/cfe-commits/attachments/20131111/6628934d/attachment.bin>