[clang-format] Add a parameter to getStyle() and guessLanguage()

[owenca]

Add a boolean parameter GuessObjC that defaults to true. This allows e.g.
clangd to bypass ObjCHeaderStyleGuesser.process() by passing false for the
parameter.

[llvmbot]

@llvm/pr-subscribers-clang-format

Author: Owen Pan (owenca)

Changes

Add a boolean parameter GuessObjC that defaults to true. This allows e.g.
clangd to bypass ObjCHeaderStyleGuesser.process() by passing false for the
parameter.

---

Full diff: https://github.com/llvm/llvm-project/pull/82911.diff

2 Files Affected:

• (modified) clang/include/clang/Format/Format.h (+7-6)
• (modified) clang/lib/Format/Format.cpp (+5-4)

diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
index e9b2160a7b9243..af635a89d21312 100644
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -5228,19 +5228,20 @@ extern const char *DefaultFallbackStyle;
 /// \param[in] AllowUnknownOptions If true, unknown format options only
 ///             emit a warning. If false, errors are emitted on unknown format
 ///             options.
+/// \param[in] GuessObjC If true, guess and see if the language is Objective-C.
 ///
 /// \returns FormatStyle as specified by ``StyleName``. If ``StyleName`` is
 /// "file" and no file is found, returns ``FallbackStyle``. If no style could be
 /// determined, returns an Error.
-llvm::Expected<FormatStyle> getStyle(StringRef StyleName, StringRef FileName,
-                                     StringRef FallbackStyle,
-                                     StringRef Code = "",
-                                     llvm::vfs::FileSystem *FS = nullptr,
-                                     bool AllowUnknownOptions = false);
+llvm::Expected<FormatStyle>
+getStyle(StringRef StyleName, StringRef FileName, StringRef FallbackStyle,
+         StringRef Code = "", llvm::vfs::FileSystem *FS = nullptr,
+         bool AllowUnknownOptions = false, bool GuessObjC = true);
 
 // Guesses the language from the ``FileName`` and ``Code`` to be formatted.
 // Defaults to FormatStyle::LK_Cpp.
-FormatStyle::LanguageKind guessLanguage(StringRef FileName, StringRef Code);
+FormatStyle::LanguageKind guessLanguage(StringRef FileName, StringRef Code,
+                                        bool GuessObjC = true);
 
 // Returns a string representation of ``Language``.
 inline StringRef getLanguageName(FormatStyle::LanguageKind Language) {
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 2f6b52510099a7..f5190745165ef6 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -3914,13 +3914,14 @@ static FormatStyle::LanguageKind getLanguageByFileName(StringRef FileName) {
   return FormatStyle::LK_Cpp;
 }
 
-FormatStyle::LanguageKind guessLanguage(StringRef FileName, StringRef Code) {
+FormatStyle::LanguageKind guessLanguage(StringRef FileName, StringRef Code,
+                                        bool GuessObjC) {
   const auto GuessedLanguage = getLanguageByFileName(FileName);
   if (GuessedLanguage == FormatStyle::LK_Cpp) {
     auto Extension = llvm::sys::path::extension(FileName);
     // If there's no file extension (or it's .h), we need to check the contents
     // of the code to see if it contains Objective-C.
-    if (Extension.empty() || Extension == ".h") {
+    if (GuessObjC && (Extension.empty() || Extension == ".h")) {
       auto NonEmptyFileName = FileName.empty() ? "guess.h" : FileName;
       Environment Env(Code, NonEmptyFileName, /*Ranges=*/{});
       ObjCHeaderStyleGuesser Guesser(Env, getLLVMStyle());
@@ -3952,8 +3953,8 @@ loadAndParseConfigFile(StringRef ConfigFile, llvm::vfs::FileSystem *FS,
 llvm::Expected<FormatStyle> getStyle(StringRef StyleName, StringRef FileName,
                                      StringRef FallbackStyleName,
                                      StringRef Code, llvm::vfs::FileSystem *FS,
-                                     bool AllowUnknownOptions) {
-  FormatStyle Style = getLLVMStyle(guessLanguage(FileName, Code));
+                                     bool AllowUnknownOptions, bool GuessObjC) {
+  FormatStyle Style = getLLVMStyle(guessLanguage(FileName, Code, GuessObjC));
   FormatStyle FallbackStyle = getNoStyle();
   if (!getPredefinedStyle(FallbackStyleName, Style.Language, &FallbackStyle))
     return make_string_error("Invalid fallback style: " + FallbackStyleName);

[owenca]

I will abandon this pull request if #82957 gets approved.