clang-format: Add special comments to disable formatting.

With this patch:
  int ThisWillBeFormatted;
  // clang-format off
  int   ThisWontBeFormatted;
  // clang-format on
  int Formatted;

This is for regions where a significantly nicer code layout can be found
knowing the content of the code.

This fixes llvm.org/PR20463.

llvm-svn: 214966

clang/lib/Format/Format.cpp

@@ -1648,6 +1648,8 @@ private:
   SmallVector<FormatToken *, 16> Tokens;
   SmallVector<IdentifierInfo *, 8> ForEachMacros;
 
+  bool FormattingDisabled = false;
+
   void readRawToken(FormatToken &Tok) {
     Lex.LexFromRawLexer(Tok.Tok);
     Tok.TokenText = StringRef(SourceMgr.getCharacterData(Tok.Tok.getLocation()),
@@ -1663,6 +1665,11 @@ private:
         Tok.Tok.setKind(tok::char_constant);
       }
     }
+    if (Tok.is(tok::comment) && Tok.TokenText == "// clang-format on")
+      FormattingDisabled = false;
+    Tok.Finalized = FormattingDisabled;
+    if (Tok.is(tok::comment) && Tok.TokenText == "// clang-format off")
+      FormattingDisabled = true;
   }
 };
 

clang/unittests/Format/FormatTest.cpp

@@ -9133,5 +9133,18 @@ TEST_F(FormatTest, HandleConflictMarkers) {
                    "int i;\n"));
 }
 
+TEST_F(FormatTest, DisableRegions) {
+  EXPECT_EQ("int i;\n"
+            "// clang-format off\n"
+            "  int j;\n"
+            "// clang-format on\n"
+            "int k;",
+            format(" int  i;\n"
+                   "   // clang-format off\n"
+                   "  int j;\n"
+                   " // clang-format on\n"
+                   "   int   k;"));
+}
+
 } // end namespace tooling
 } // end namespace clang