Allow specifying a path on which to pronto run

Example `pronto run -f github lib/pronto/github.rb`

CHANGELOG.md

@@ -7,6 +7,7 @@
 * Try to detect pull request id automatically, if `PULL_REQUEST_ID` is not specified. Inspired by @willnet/prid.
 * [#40](https://github.com/mmozuras/pronto/issues/40): Add '--index' option for 'pronto run'. Pronto analyzes changes before committing.
 * [#50](https://github.com/mmozuras/pronto/pull/50): Adds GitLab formatter
+* [#52](https://github.com/mmozuras/pronto/pull/52): Allow specifying a path for 'pronto run'.
 
 ### Changes
 * Github and Github pull request formatters now filter out duplicate offenses on the same line to avoid spamming with redundant comments.

lib/pronto.rb

@@ -23,15 +23,16 @@
 require 'pronto/formatter/formatter'
 
 module Pronto
-  def self.run(commit = 'master', repo_path = '.', formatter = nil)
+  def self.run(commit = 'master', repo_path = '.',
+               formatter = Formatter::TextFormatter.new, file = nil)
     commit ||= 'master'
 
     repo = Git::Repository.new(repo_path)
-    patches = repo.diff(commit)
+    options = { paths: [file] } if file
+    patches = repo.diff(commit, options)
 
     result = run_all_runners(patches)
 
-    formatter ||= default_formatter
     puts formatter.format(result, repo)
 
     result
@@ -59,8 +60,4 @@ def self.run_all_runners(patches)
       runner.new.run(patches, patches.commit)
     end.flatten.compact
   end
-
-  def default_formatter
-    Formatter::TextFormatter.new
-  end
 end

lib/pronto/cli.rb

@@ -41,15 +41,15 @@ def is_thor_reserved_word?(word, type)
                   aliases: '-f',
                   banner: "Pick output formatter. Available: #{::Pronto::Formatter.names.join(', ')}"
 
-    def run
+    def run(path = nil)
       gem_names = options[:runner].any? ? options[:runner] : ::Pronto.gem_names
       gem_names.each do |gem_name|
         require "pronto/#{gem_name}"
       end
 
       formatter = ::Pronto::Formatter.get(options[:formatter])
       commit = options[:index] ? :index : options[:commit]
-      messages = ::Pronto.run(commit, '.', formatter)
+      messages = ::Pronto.run(commit, '.', formatter, path)
       exit(messages.count) if options[:'exit-code']
     rescue Rugged::RepositoryError
       puts '"pronto" should be run from a git repository'

lib/pronto/git/repository.rb

@@ -7,13 +7,13 @@ def initialize(path)
         @repo = Rugged::Repository.new(path)
       end
 
-      def diff(commit)
+      def diff(commit, options = nil)
         if commit == :index
-          patches = @repo.index.diff
+          patches = @repo.index.diff(options)
           Patches.new(self, head, patches)
         else
           merge_base = merge_base(commit)
-          patches = @repo.diff(merge_base, head)
+          patches = @repo.diff(merge_base, head, options)
           Patches.new(self, merge_base, patches)
         end
       end