Extracting duplicated code to a private method.

3 files changed, 37 insertions, 42 deletions

diff --git a/lib/diff/lcs.rb b/lib/diff/lcs.rb
index 4017dba..d8b6f08 100644
--- a/lib/diff/lcs.rb
+++ b/lib/diff/lcs.rb
@@ -244,26 +244,8 @@ class << Diff::LCS
   # initialise it. If the +callbacks+ object (possibly initialised) responds
   # to #finish, it will be called.
   def diff(seq1, seq2, callbacks = nil, &block) # :yields diff changes:
-    callbacks ||= Diff::LCS::DiffCallbacks
-    if callbacks.kind_of?(Class)
-      cb = callbacks.new rescue callbacks
-      callbacks = cb
-    end
-    traverse_sequences(seq1, seq2, callbacks)
-    callbacks.finish if callbacks.respond_to?(:finish)
-
-    if block_given?
-      res = callbacks.diffs.map do |hunk|
-        if hunk.kind_of?(Array)
-          hunk = hunk.map { |hunk_block| yield hunk_block }
-        else
-          yield hunk
-        end
-      end
-      res
-    else
-      callbacks.diffs
-    end
+    diff_traversal(:diff, seq1, seq2, callbacks || Diff::LCS::DiffCallbacks,
+                   &block)
   end
 
   # #sdiff computes all necessary components to show two sequences and their
@@ -281,26 +263,8 @@ class << Diff::LCS
   # initialise it. If the +callbacks+ object (possibly initialised) responds
   # to #finish, it will be called.
   def sdiff(seq1, seq2, callbacks = nil, &block) #:yields diff changes:
-    callbacks ||= Diff::LCS::SDiffCallbacks
-    if callbacks.kind_of?(Class)
-      cb = callbacks.new rescue callbacks
-      callbacks = cb
-    end
-    traverse_balanced(seq1, seq2, callbacks)
-    callbacks.finish if callbacks.respond_to?(:finish)
-
-    if block_given?
-      res = callbacks.diffs.map do |hunk|
-        if hunk.kind_of?(Array)
-          hunk = hunk.map { |hunk_block| yield hunk_block }
-        else
-          yield hunk
-        end
-      end
-      res
-    else
-      callbacks.diffs
-    end
+    diff_traversal(:sdiff, seq1, seq2, callbacks || Diff::LCS::SDiffCallbacks,
+                   &block)
   end
 
   # #traverse_sequences is the most general facility provided by this
@@ -385,6 +349,7 @@ class << Diff::LCS
   # sequence is reached, if +a+ has not yet reached the end of +A+ or +b+
   # has not yet reached the end of +B+.
   def traverse_sequences(seq1, seq2, callbacks = Diff::LCS::SequenceCallbacks, &block) #:yields change events:
+    callbacks ||= Diff::LCS::SequenceCallbacks
     matches = Diff::LCS::Internals.lcs(seq1, seq2)
 
     run_finished_a = run_finished_b = false
@@ -735,7 +700,7 @@ class << Diff::LCS
     # Start with a new empty type of the source's class
     res = src.class.new
 
-    direction ||= Diff::LCS::Internals.diff_direction(src, patchset)
+    direction ||= Diff::LCS::Internals.intuit_diff_direction(src, patchset)
 
     ai = bj = 0
 
diff --git a/lib/diff/lcs/callbacks.rb b/lib/diff/lcs/callbacks.rb
index c0658b6..8eec5fc 100644
--- a/lib/diff/lcs/callbacks.rb
+++ b/lib/diff/lcs/callbacks.rb
@@ -45,6 +45,10 @@ module Diff::LCS
   #
   #     Diff::LCS.LCS(seq1, seq2, Diff::LCS::BalancedCallbacks)
   BalancedCallbacks = DefaultCallbacks
+
+  def self.callbacks_for(callbacks)
+    callbacks.new rescue callbacks
+  end
 end
 
 # This will produce a compound array of simple diff change objects. Each
diff --git a/lib/diff/lcs/internals.rb b/lib/diff/lcs/internals.rb
index 31e7331..fe4ed9b 100644
--- a/lib/diff/lcs/internals.rb
+++ b/lib/diff/lcs/internals.rb
@@ -1,5 +1,31 @@
 # -*- ruby encoding: utf-8 -*-
 
+class << Diff::LCS
+  def diff_traversal(method, seq1, seq2, callbacks, &block)
+    callbacks = callbacks_for(callbacks)
+    case method
+    when :diff
+      traverse_sequences(seq1, seq2, callbacks)
+    when :sdiff
+      traverse_balanced(seq1, seq2, callbacks)
+    end
+    callbacks.finish if callbacks.respond_to? :finish
+
+    if block
+      callbacks.diffs.map do |hunk|
+        if hunk.kind_of? Array
+          hunk.map { |hunk_block| block[hunk_block] }
+        else
+          block[hunk]
+        end
+      end
+    else
+      callbacks.diffs
+    end
+  end
+  private :diff_traversal
+end
+
 module Diff::LCS::Internals # :nodoc:
 end
 
@@ -117,7 +143,7 @@ class << Diff::LCS::Internals
   # of one of the above.
   #
   # Note: This will be deprecated as a public function in a future release.
-  def diff_direction(src, patchset, limit = nil)
+  def intuit_diff_direction(src, patchset, limit = nil)
     string = src.kind_of?(String)
     count = left_match = left_miss = right_match = right_miss = 0