#531 add API to get default branch

Signed-off-by: Alexande B <abobrikovich@gmail.com>

lib/git.rb

@@ -308,4 +308,12 @@ def self.ls_remote(location = nil, options = {})
   def self.open(working_dir, options = {})
     Base.open(working_dir, options)
   end
+
+  # returns a String containing information about the default remote branch
+  # of the target repository
+  #
+  # @param [String|NilClass] location the target repository location or nil for '.'
+  def self.remote_default_branch(location = '.')
+    Base.open(location).remote.default_branch
+  end
 end

lib/git/lib.rb

@@ -399,6 +399,20 @@ def branch_current
       branches_all.select { |b| b[1] }.first[0] rescue nil
     end
 
+    def branch_default
+      begin
+        full_name = command("symbolic-ref", "refs/remotes/origin/HEAD")
+        return full_name.gsub(%r{^refs/remotes/origin/}, "")
+      rescue Git::GitExecuteError
+        begin
+          full_name = command("symbolic-ref", "refs/origin/HEAD")
+          return full_name.gsub(%r{^refs/origin/}, "")
+        rescue Git::GitExecuteError
+          return command("symbolic-ref", "--short", "HEAD")
+        end
+      end
+    end
+
     def branch_contains(commit, branch_name="")
       command("branch",  [branch_name, "--contains", commit])
     end

lib/git/remote.rb

@@ -27,6 +27,11 @@ def branch(branch = 'master')
     def remove
       @base.lib.remote_remove(@name)     
     end
+
+    # @return [String] name of default branch
+    def default_branch
+      @base.lib.branch_default
+    end
 
     def to_s
       @name

tests/units/test_git_path.rb

@@ -44,4 +44,7 @@ def test_readables_in_temp_dir
     end
   end
 
+  def test_default_branch
+    assert_equal(@git.remote.default_branch, "git_grep")
+  end
 end

tests/units/test_lib.rb

@@ -291,4 +291,9 @@ def test_show
     assert(@lib.show('gitsearch1', 'scott/text.txt') == "hello\nthis is\na file\nthat is\nput here\nto search one\nto search two\nnothing!\n")
   end
 
+  def test_branch_default
+    assert_equal(@lib.branch_default, "git_grep")
+    @lib.change_head_branch("master")
+    assert_equal(@lib.branch_default, "master")
+  end
 end