[PATCH] Multi-line comment alignment

[Alexander Kornienko]

Hi djasper,

Aligns continuation lines of multi-line comments to the base
indentation level +1:
class A {
  /*
   * test
   */
  void f() {}
};

The first revision is work in progress. The implementation is not yet complete.

http://llvm-reviews.chandlerc.com/D541

Files:
  lib/Format/Format.cpp
  unittests/Format/FormatTest.cpp

Index: lib/Format/Format.cpp
===================================================================
--- lib/Format/Format.cpp
+++ lib/Format/Format.cpp
@@ -128,24 +128,25 @@
       if (Tok.Parent != NULL || !Comments.empty()) {
         if (Style.ColumnLimit >=
             Spaces + WhitespaceStartColumn + Tok.FormatTok.TokenLength) {
-          Comments.push_back(StoredComment());
-          Comments.back().Tok = Tok.FormatTok;
-          Comments.back().Spaces = Spaces;
-          Comments.back().NewLines = NewLines;
-          if (NewLines == 0)
-            Comments.back().MinColumn = WhitespaceStartColumn + Spaces;
-          else
-            Comments.back().MinColumn = Spaces;
-          Comments.back().MaxColumn =
-              Style.ColumnLimit - Tok.FormatTok.TokenLength;
+          StoredComment SC;
+          SC.Tok = Tok.FormatTok;
+          SC.Spaces = Spaces;
+          SC.NewLines = NewLines;
+          SC.MinColumn = NewLines > 0 ? Spaces : WhitespaceStartColumn + Spaces;
+          SC.MaxColumn = Style.ColumnLimit - Tok.FormatTok.TokenLength;
+          Comments.push_back(SC);
           return;
         }
       }
     }
 
     // If this line does not have a trailing comment, align the stored comments.
     if (Tok.Children.empty() && !isTrailingComment(Tok))
       alignComments();
+
+    if (Tok.Type == TT_BlockComment)
+      alignBlockComment(Tok.FormatTok);
+
     storeReplacement(Tok.FormatTok, getNewLineText(NewLines, Spaces));
   }
 
@@ -191,6 +192,33 @@
   }
 
 private:
+  void alignBlockComment(const FormatToken &Tok) {
+    int BaseIndent = 0; // FIXME
+    const char *Start = SourceMgr.getCharacterData(Tok.WhiteSpaceStart);
+    const char *Cur = Start + Tok.WhiteSpaceLength;
+
+    for (const char *TokEnd = Cur + Tok.TokenLength; Cur < TokEnd; ++Cur) {
+      if (*Cur == '\n') {
+        ++Cur;
+        int Indent = BaseIndent;
+        int Spaces = 0;
+        while (Cur + Spaces < TokEnd && Cur[Spaces] == ' ')
+          ++Spaces;
+        if (Cur + Spaces < TokEnd && Cur[Spaces] == '*')
+          ++Indent;
+
+        SourceLocation Loc = Tok.WhiteSpaceStart.getLocWithOffset(Cur - Start);
+        if (Spaces < Indent)
+          Replaces.insert(tooling::Replacement(
+              SourceMgr, Loc, 0, std::string(Indent - Spaces, ' ')));
+        else if (Spaces > Indent)
+          Replaces.insert(
+              tooling::Replacement(SourceMgr, Loc, Spaces - Indent, ""));
+        --Cur;
+      }
+    }
+  }
+
   std::string getNewLineText(unsigned NewLines, unsigned Spaces) {
     return std::string(NewLines, '\n') + std::string(Spaces, ' ');
   }
@@ -227,8 +255,7 @@
     unsigned MinColumn = 0;
     unsigned MaxColumn = UINT_MAX;
     comment_iterator Start = Comments.begin();
-    for (comment_iterator I = Comments.begin(), E = Comments.end(); I != E;
-         ++I) {
+    for (comment_iterator I = Start, E = Comments.end(); I != E; ++I) {
       if (I->MinColumn > MaxColumn || I->MaxColumn < MinColumn) {
         alignComments(Start, I, MinColumn);
         MinColumn = I->MinColumn;
Index: unittests/Format/FormatTest.cpp
===================================================================
--- unittests/Format/FormatTest.cpp
+++ unittests/Format/FormatTest.cpp
@@ -608,6 +608,33 @@
                NoBinPacking);
 }
 
+TEST_F(FormatTest, AlignsMultiLineComments) {
+  EXPECT_EQ("/*\n"
+            " * Really multi-line\n"
+            " * comment.\n"
+            " */\n"
+            "void f() {}",
+            format("  /*\n"
+                   "   * Really multi-line\n"
+                   "   * comment.\n"
+                   "   */\n"
+                   "  void f() {}"));
+  EXPECT_EQ("class C {\n"
+            "  /*\n"
+            "   * Another multi-line\n"
+            "   * comment.\n"
+            "   */\n"
+            "  void f() {}\n"
+            "};",
+            format("class C {\n"
+                   "/*\n"
+                   " * Another multi-line\n"
+                   " * comment.\n"
+                   " */\n"
+                   "void f() {}\n"
+                   "};"));
+}
+
 TEST_F(FormatTest, CommentsInStaticInitializers) {
   EXPECT_EQ(
       "static SomeType type = { aaaaaaaaaaaaaaaaaaaa, /* comment */\n"
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