[PATCH] D142804: [clang-format] Support clang-format on/off line comments as prefixes

[Alex via Phabricator via cfe-commits]

alexolog added inline comments.


================
Comment at: clang/lib/Format/Format.cpp:3893
 
+bool isClangFormatOn(StringRef Comment) {
+  if (Comment == "/* clang-format on */")
----------------
alexolog wrote:
> Here's my attempt at something flexible:
> Disclaimer: this is my first time looking at the LLVM codebase, so don't expect production quality.
> 
> ```
> ////////////////////////////////////////////////////////////////////////////////////////////////////
> 
> // Implementation detail, hide in a namespace and/or take out of the header
> bool isClangFormatMarked(StringRef Comment, StringRef Mark) {
>   // Quick heuristics: minimum length and starts with a slash (comment)
>   // Shortest tag: "//clang-format on", 17 characters
>   static constexpr StringLiteral clangFormatStr("clang-format ");
>   if (Comment.size() < clangFormatStr.size() + 4 || Comment[0] != '/')
>     return false;
> 
>   // check if it's a comment starting with "//" or "/*"
>   bool CloseNeeded = false;
>   if (Comment[1] == '*')
>     CloseNeeded = true;
>   else if (Comment[1] != '/')
>     return false;
> 
>   // Remove the comment start and all following whitespace
>   Comment = Comment.substr(2).ltrim();
> 
>   // Check for the actual command, a piece at a time
>   if (!Comment.consume_front(clangFormatStr) || !Comment.consume_front(Mark))
>     return false;
> 
>   // Are we there yet?
>   if (!CloseNeeded && Comment.empty() ||
>       CloseNeeded && Comment.starts_with("*/"))
>     return true;
> 
>   // For a trailer, restrict the next character
>   // (currently spaces and tabs, but can include a colon, etc.)
>   static constexpr StringLiteral Separator(" \t");
>   if (!Separator.contains(Comment[0]))
>     return false;
>   
>   // Verify comment is properly terminated
>   if (!CloseNeeded || Comment.contains("*/"))
>     return true;
> 
>   return false; // Everything else
> }
> 
> ////////////////////////////////////////////////////////////////////////////////////////////////////
> 
> bool isClangFormatOn(StringRef Comment) {
>   return isClangFormatMarked(Comment, "on");
> }
> 
> bool isClangFormatOff(StringRef Comment) {
>   return isClangFormatMarked(Comment, "off");
> }
> 
> ////////////////////////////////////////////////////////////////////////////////////////////////////
> 
>   EXPECT_TRUE(isClangFormatOn("//clang-format on"));
>   EXPECT_TRUE(isClangFormatOn("// clang-format on"));
>   EXPECT_TRUE(isClangFormatOn("//clang-format on "));
>   EXPECT_TRUE(isClangFormatOn("//clang-format on and off"));
>   EXPECT_TRUE(isClangFormatOn("/*clang-format on*/"));
>   EXPECT_TRUE(isClangFormatOn("/* clang-format on*/"));
>   EXPECT_TRUE(isClangFormatOn("/*clang-format on */"));
>   EXPECT_TRUE(isClangFormatOn("/*clang-format on*/int i{0};"));
> 
>   EXPECT_FALSE(isClangFormatOn("//clang-format  on"));
>   EXPECT_FALSE(isClangFormatOn("//clang-format o"));
>   EXPECT_FALSE(isClangFormatOn("//     clang-format o"));
>   EXPECT_FALSE(isClangFormatOn("//clang-format ontario"));
>   EXPECT_FALSE(isClangFormatOn("//clang-format off"));
>   EXPECT_FALSE(isClangFormatOn("/*clang-format onwards*/"));
> 
> ////////////////////////////////////////////////////////////////////////////////////////////////////
> ```
Sorry about the "done".  My misunderstanding


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  https://reviews.llvm.org/D142804/new/

https://reviews.llvm.org/D142804