Adopt clang-format for code formatting

Author: st0012

.clang-format

@@ -0,0 +1,11 @@
+---
+BasedOnStyle: LLVM
+Language: Cpp
+
+UseTab: Never
+IndentWidth: 2
+ColumnLimit: 0
+SortIncludes: Never
+Cpp11BracedListStyle: false
+SpaceAfterCStyleCast: true
+AllowShortIfStatementsOnASingleLine: Always

.github/workflows/clang-format.yml

@@ -0,0 +1,34 @@
+name: C Code Linting
+
+on:
+  push:
+    paths:
+      - '**.c'
+      - '**.h'
+      - '.clang-format'
+      - '.github/workflows/clang-format.yml'
+  pull_request:
+    paths:
+      - '**.c'
+      - '**.h'
+      - '.clang-format'
+      - '.github/workflows/clang-format.yml'
+
+jobs:
+  format-check:
+    runs-on: ubuntu-latest
+
+    steps:
+    - uses: actions/checkout@v3
+
+    - name: Install clang-format
+      run: sudo apt-get install -y clang-format
+
+    - name: Setup Ruby
+      uses: ruby/setup-ruby@v1
+      with:
+        ruby-version: '3.4'
+        bundler-cache: true
+
+    - name: Check C code linting
+      run: bundle exec rake format:c_check

.vscode/extensions.json

@@ -0,0 +1,5 @@
+{
+  "recommendations": [
+    "llvm-vs-code-extensions.vscode-clangd"
+  ]
+}

Gemfile.lock

@@ -125,7 +125,7 @@ GEM
     rubocop-ast (1.44.1)
       parser (>= 3.3.7.2)
       prism (~> 1.4)
-    rubocop-on-rbs (1.5.0)
+    rubocop-on-rbs (1.6.0)
       lint_roller (~> 1.1)
       rbs (~> 3.5)
       rubocop (>= 1.72.1, < 2.0)
@@ -157,7 +157,7 @@ GEM
       uri (>= 0.12.0)
     stringio (3.1.7)
     strong_json (2.1.2)
-    strscan (3.1.3)
+    strscan (3.1.4)
     tempfile (0.3.1)
     terminal-table (4.0.0)
       unicode-display_width (>= 1.1.1, < 4)

README.md

@@ -198,6 +198,43 @@ After checking out the repo, run `bin/setup` to install dependencies. Then, run
 
 To install this gem onto your local machine, run `bundle exec rake install`. To release a new version, update the version number in `version.rb`, and then run `bundle exec rake release`, which will create a git tag for the version, push git commits and tags, and push the `.gem` file to [rubygems.org](https://rubygems.org).
 
+### C Code Formatting
+
+This project uses `clang-format` to enforce consistent formatting of C code with a `.clang-format` configuration in the root directory.
+
+#### Setup
+
+First, install clang-format:
+
+```bash
+# macOS
+brew install clang-format
+
+# Ubuntu/Debian
+sudo apt-get install clang-format
+
+# Windows
+choco install llvm
+```
+
+#### Usage
+
+Format all C source files:
+
+```bash
+rake format:c
+```
+
+Check formatting without making changes:
+
+```bash
+rake format:c_check
+```
+
+#### Editor Integration
+
+For VS Code users, install the "clangd" extension which will automatically use the project's `.clang-format` file.
+
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/ruby/rbs.

Rakefile

@@ -49,6 +49,78 @@ task :confirm_templates => :templates do
   sh "git diff --exit-code -- include src"
 end
 
+# Task to format C code using clang-format
+namespace :format do
+  dirs = ["src", "ext", "include"]
+  excluded_files = ["ext/rbs_extension/lexer.c"]
+
+  # Find all C source and header files, then filter out excluded files
+  files = `find #{dirs.join(" ")} -type f -name "*.c" -o -name "*.h"`.split("\n").reject do |file|
+    excluded_files.include?(file)
+  end
+
+  desc "Format C source files using clang-format"
+  task :c do
+    puts "Formatting C files..."
+
+    # Check if clang-format is installed
+    unless system("which clang-format > /dev/null 2>&1")
+      abort "Error: clang-format not found. Please install clang-format first."
+    end
+
+    if files.empty?
+      puts "No C files found to format"
+      next
+    end
+
+    puts "Found #{files.length} files to format (excluding generated files)"
+
+    exit_status = 0
+    files.each do |file|
+      puts "Formatting #{file}"
+      unless system("clang-format -i -style=file #{file}")
+        puts "❌ Error formatting #{file}"
+        exit_status = 1
+      end
+    end
+
+    exit exit_status unless exit_status == 0
+    puts "✅ All files formatted successfully"
+  end
+
+  desc "Check if C source files are properly formatted"
+  task :c_check do
+    puts "Checking C file formatting..."
+
+    # Check if clang-format is installed
+    unless system("which clang-format > /dev/null 2>&1")
+      abort "Error: clang-format not found. Please install clang-format first."
+    end
+
+    if files.empty?
+      puts "No C files found to check"
+      next
+    end
+
+    puts "Found #{files.length} files to check (excluding generated files)"
+
+    needs_format = false
+    files.each do |file|
+      unless system("clang-format --dry-run -Werror -style=file #{file} >/dev/null 2>&1")
+        puts "❌ #{file} needs formatting"
+        needs_format = true
+      end
+    end
+
+    if needs_format
+      warn "Some files need formatting. Run 'rake format:c' to format them."
+      exit 1
+    else
+      puts "✅ All files are properly formatted"
+    end
+  end
+end
+
 rule ".c" => ".re" do |t|
   puts "⚠️⚠️⚠️ #{t.name} is older than #{t.source}. You may need to run `rake lexer` ⚠️⚠️⚠️"
 end

ext/rbs_extension/location.c

@@ -257,7 +257,7 @@ static VALUE location_aref(VALUE self, VALUE name) {
 }
 
 static VALUE rbs_constant_to_ruby_symbol(rbs_constant_t *constant) {
-  return ID2SYM(rb_intern2((const char *) constant->start, constant->length));
+  return ID2SYM(rb_intern2((const char *)constant->start, constant->length));
 }
 
 static VALUE location_optional_keys(VALUE self) {