Initial commit

lib/format-staged.rb

@@ -0,0 +1,109 @@
+require 'format-staged/version'
+require 'format-staged/entry'
+require 'format-staged/io'
+require 'shellwords'
+
+class FormatStaged 
+  attr_reader :formatter, :patterns, :update, :write, :verbose
+  
+  def initialize(formatter:, patterns:, update: true, write: true, verbose: true) 
+    @formatter = formatter
+    @patterns = patterns
+    @update = update
+    @write = write
+    @verbose = verbose
+  end
+  
+  def run()
+    root = get_output('git', 'rev-parse', '--show-toplevel').first
+    
+    files = get_output('git', 'diff-index', '--cached', '--diff-filter=AM', '--no-renames', 'HEAD')
+      .map { |line| Entry.new(line, root: root) }
+      .reject { |entry| entry.symlink? }
+      .filter { |entry| entry.matches?(@patterns) }
+      
+      files.each do |file|
+        format_file(file)
+      end
+    end
+    
+    def format_file(file) 
+      new_hash = format_object file
+      
+      return true if not write 
+
+      if new_hash == file.dst_hash
+        puts "Unchanged #{file.src_path}"
+        return false
+      end
+      
+      if object_is_empty new_hash
+        puts "Skipping #{file.src_path}, formatted file is empty"
+        return false
+      end
+
+      replace_file_in_index file, new_hash
+      
+      if update
+        begin
+          patch_working_file file, new_hash
+        rescue => error
+          puts "Warning: failed updating #{file.src_path} in working copy: #{error}"
+        end
+      end
+      
+      true
+    end
+    
+    def format_object(file)
+      puts "Formatting #{file.src_path}"
+      
+      format_command = formatter.sub("{}", file.src_path.shellescape)
+      
+      pid1, r = pipe_command "git", "cat-file", "-p", file.dst_hash
+      pid2, r = pipe_command format_command, source: r
+      pid3, r = pipe_command "git", "hash-object", "-w", "--stdin", source: r
+      
+      result = r.readlines.map { |it| it.chomp }
+      if @verbose
+        result.each do |line|
+          puts "< #{line}"
+        end
+      end
+    
+      Process.wait pid1
+      raise "Cannot read #{file.dst_hash} from object database" unless $?.success?
+      
+      Process.wait pid2
+      raise "Error formatting #{file.src_path}" unless $?.success?
+      
+      Process.wait pid3
+      raise "Error writing formatted file back to object database" unless $?.success? && !result.empty?
+      
+      result.first
+    end
+    
+    def object_is_empty(hash)
+      size = get_output("git", "cat-file", "-s", hash).first.to_i
+      size == 0
+    end
+
+    def patch_working_file(file, new_hash)
+      patch = get_output "git", "diff", file.dst_hash, new_hash, lines: false
+      patch.gsub! "a/#{file.dst_hash}", "a/#{file.src_path}"
+      patch.gsub! "b/#{new_hash}", "b/#{file.src_path}"
+
+      input, patch_out = IO.pipe
+      pid, r = pipe_command "git", "apply", "-", source: input
+      
+      patch_out.write patch
+      patch_out.close
+      
+      Process.wait pid
+      raise "Error applying patch" unless $?.success?
+    end
+
+    def replace_file_in_index(file, new_hash)
+      get_output "git", "update-index", "--cacheinfo", "#{file.dst_mode},#{new_hash},#{file.src_path}"
+    end
+end

lib/format-staged/entry.rb

@@ -0,0 +1,35 @@
+class FormatStaged 
+  class Entry
+    PATTERN = /^:(?<src_mode>\d+) (?<dst_mode>\d+) (?<src_hash>[a-f0-9]+) (?<dst_hash>[a-f0-9]+) (?<status>[A-Z])(?<score>\d+)?\t(?<src_path>[^\t]+)(?:\t(?<dst_path>[^\t]+))?$/
+
+    attr_reader :src_mode, :dst_mode, :src_hash, :dst_hash, :status, :score, :src_path, :dst_path, :path, :root
+    
+    def initialize(line, root:)
+      matches = line.match(PATTERN) or raise "Cannot parse output #{line}"
+      @src_mode = matches[:src_mode]
+      @dst_mode = matches[:dst_mode]
+      @src_hash = matches[:src_hash]
+      @dst_hash = matches[:dst_hash]
+      @status = matches[:status]
+      @score = matches[:score]&.to_i
+      @src_path = matches[:src_path]
+      @dst_path = matches[:dst_path]
+      @path = File.expand_path(@src_path, root)
+      @root = root
+    end
+    
+    def symlink?
+      @dst_mode == '120000'
+    end
+    
+    def matches?(patterns)
+      result = false
+      patterns.each do |pattern|
+        if File.fnmatch? pattern, path, File::FNM_EXTGLOB
+          result = true
+        end
+      end
+      result
+    end
+  end
+end

lib/format-staged/io.rb

@@ -0,0 +1,40 @@
+class FormatStaged 
+  def get_output(*args, lines: true)
+    puts '> ' + args.join(' ') if @verbose
+    
+    output = IO.popen(args, err: :err) do |io|
+      if lines
+        io.readlines.map { |l| l.chomp }
+      else
+        io.read
+      end
+    end
+    
+    if @verbose and lines
+      output.each do |line|
+        puts "< #{line}"
+      end
+    end
+    
+    raise "Failed to run command" unless $?.success?
+    
+    output
+  end
+  
+  def pipe_command(*args, source: nil)
+    puts (source.nil? ? '> ' : '| ') + args.join(' ')  if @verbose
+    r, w = IO.pipe
+    
+    opts = {}
+    opts[:in] = source unless source.nil?
+    opts[:out] = w
+    opts[:err] = :err
+    
+    pid = spawn(*args, **opts)
+    
+    w.close
+    source &.close
+    
+    return [pid, r]
+  end  
+end

lib/format-staged/version.rb

@@ -0,0 +1,3 @@
+class FormatStaged
+  VERSION = "0.0.1"
+end