Added git-blame command

Tim Morgan · Tim Morgan · commit 01476fffba36 · 2012-05-11T15:34:16.000-07:00
diff --git a/lib/git.rb b/lib/git.rb
@@ -13,6 +13,7 @@
 require 'git/working_directory'
 
 require 'git/log'
+require 'git/blame'
 require 'git/object'
 
 require 'git/branches'
diff --git a/lib/git/base.rb b/lib/git/base.rb
@@ -170,6 +170,12 @@ def log(count = 30)
       Git::Log.new(self, count)
     end
 
+    # returns a Git::BlameResult object with the commits that most recently
+    # modified each line
+    def blame(file, opts={})
+      Git::Blame.new(self, file, opts).result
+    end
+
     # returns a Git::Status object
     def status
       Git::Status.new(self)
diff --git a/lib/git/blame.rb b/lib/git/blame.rb
@@ -0,0 +1,46 @@
+class Git::Blame
+  attr_reader :result
+
+  def initialize(base, file, opts={})
+    @base = base
+    @file = file
+    @options = opts
+
+    @result = run_blame
+  end
+
+  private
+
+  def run_blame
+    lines = @base.lib.blame(@file, @options)
+    result = Git::BlameResult.new(@base)
+    lines.each do |line|
+      words = line.split(/\s+/)
+      next unless words.first.length == 40 #TODO this breaks if git ever introduces a 40-character attribute name
+      ref = words[0]
+      block_start = words[2].to_i
+      block_length = words[3].to_i
+      result.add_block ref, block_start, block_length
+    end
+    result
+  end
+end
+
+class Git::BlameResult
+  delegate :[], :each, :each_with_index, to: :lines
+
+  def initialize(base)
+    @base = base
+    @commit_cache = {}
+    @lines = []
+  end
+
+  def add_block(ref, start, length)
+    commit = (@commit_cache[ref] ||= @base.object(ref))
+    length.times { |i| @lines[start + i] = commit }
+    commit
+  end
+
+  attr_reader :lines
+  private :lines
+end
diff --git a/lib/git/lib.rb b/lib/git/lib.rb
@@ -92,6 +92,31 @@ def full_log_commits(opts = {})
       full_log = command_lines('log', arr_opts, true)
       process_commit_data(full_log)
     end
+
+    def blame(file, opts={})
+      arr_opts = %w( --incremental )
+      arr_opts << "-L#{opts[:start]},#{opts[:end]}" if opts[:start] && opts[:end]
+      arr_opts << '--reverse' if opts[:reverse]
+      case opts[:detect_intrafile_moves]
+        when true then arr_opts << '-M'
+        when Fixnum then arr_opts << "-M#{opts[:detect_intrafile_moves]}"
+      end
+      if opts[:detect_interfile_moves]
+        c_opt = if opts[:check_all_commits_for_interfile_moves]
+                  '-CCC'
+                elsif opts[:check_first_file_commit_for_interfile_moves]
+                  '-CC'
+                else
+                  '-C'
+                end
+        c_opt << opts[:detect_interfile_moves] if opts[:detect_interfile_moves].kind_of?(Fixnum)
+      end
+      arr_opts << '-w' if opts[:ignore_whitespace]
+      arr_opts << opts[:revision] if opts[:revision]
+      arr_opts << '--' << file
+
+      command_lines 'blame', arr_opts
+    end
     
     def revparse(string)
       return string if string =~ /[A-Fa-f0-9]{40}/  # passing in a sha - just no-op it
