[clang] [clang-format] Add -ConfigFile option (PR #113864)

[Owen Pan via cfe-commits]

https://github.com/owenca updated https://github.com/llvm/llvm-project/pull/113864

>From b5f89c18b22bbc07d2f4fcbc2896996efea52478 Mon Sep 17 00:00:00 2001
From: Owen Pan <owenpiano at gmail.com>
Date: Sun, 27 Oct 2024 22:22:11 -0700
Subject: [PATCH] [clang-format] Add -ConfigFile option

Close #107808.
---
 clang/include/clang/Format/Format.h |  5 +++++
 clang/lib/Format/Format.cpp         | 17 +++++++++++++++++
 2 files changed, 22 insertions(+)

diff --git a/clang/include/clang/Format/Format.h b/clang/include/clang/Format/Format.h
index c9b72e65cb236d..1380223493187a 100644
--- a/clang/include/clang/Format/Format.h
+++ b/clang/include/clang/Format/Format.h
@@ -2481,6 +2481,10 @@ struct FormatStyle {
   /// \version 5
   bool CompactNamespaces;
 
+  ///
+  /// \version 20
+  std::string ConfigFile;
+
   /// This option is **deprecated**. See ``CurrentLine`` of
   /// ``PackConstructorInitializers``.
   /// \version 3.7
@@ -5195,6 +5199,7 @@ struct FormatStyle {
            BreakTemplateDeclarations == R.BreakTemplateDeclarations &&
            ColumnLimit == R.ColumnLimit && CommentPragmas == R.CommentPragmas &&
            CompactNamespaces == R.CompactNamespaces &&
+           ConfigFile == R.ConfigFile &&
            ConstructorInitializerIndentWidth ==
                R.ConstructorInitializerIndentWidth &&
            ContinuationIndentWidth == R.ContinuationIndentWidth &&
diff --git a/clang/lib/Format/Format.cpp b/clang/lib/Format/Format.cpp
index 0cf4cdbeab31f3..379aec9e19a5fb 100644
--- a/clang/lib/Format/Format.cpp
+++ b/clang/lib/Format/Format.cpp
@@ -1163,6 +1163,7 @@ template <> struct MappingTraits<FormatStyle> {
     IO.mapOptional("TemplateNames", Style.TemplateNames);
     IO.mapOptional("TypeNames", Style.TypeNames);
     IO.mapOptional("TypenameMacros", Style.TypenameMacros);
+    IO.mapOptional("ConfigFile", Style.ConfigFile);
     IO.mapOptional("UseTab", Style.UseTab);
     IO.mapOptional("VerilogBreakBetweenInstancePorts",
                    Style.VerilogBreakBetweenInstancePorts);
@@ -2046,6 +2047,11 @@ ParseError validateQualifierOrder(FormatStyle *Style) {
   return ParseError::Success;
 }
 
+llvm::ErrorOr<std::unique_ptr<llvm::MemoryBuffer>>
+loadAndParseConfigFile(StringRef ConfigFile, llvm::vfs::FileSystem *FS,
+                       FormatStyle *Style, bool AllowUnknownOptions,
+                       llvm::SourceMgr::DiagHandlerTy DiagHandler);
+
 std::error_code parseConfiguration(llvm::MemoryBufferRef Config,
                                    FormatStyle *Style, bool AllowUnknownOptions,
                                    llvm::SourceMgr::DiagHandlerTy DiagHandler,
@@ -2102,6 +2108,17 @@ std::error_code parseConfiguration(llvm::MemoryBufferRef Config,
     StyleSet.Add(std::move(DefaultStyle));
   }
   *Style = *StyleSet.Get(Language);
+  std::string ConfigFile;
+  if (!Style->ConfigFile.empty()) {
+    auto *FS = llvm::vfs::getRealFileSystem().get();
+    assert(FS);
+    ConfigFile = Style->ConfigFile;
+    Style->ConfigFile.clear();
+    const auto Text = loadAndParseConfigFile(ConfigFile, FS, Style,
+                                             AllowUnknownOptions, DiagHandler);
+    if (Text.getError())
+      return make_error_code(ParseError::Error);
+  }
   if (Style->InsertTrailingCommas != FormatStyle::TCS_None &&
       Style->BinPackArguments) {
     // See comment on FormatStyle::TSC_Wrapped.