Module: HashDiff
- Defined in:
- lib/hashdiff/patch.rb,
lib/hashdiff/lcs.rb,
lib/hashdiff/diff.rb,
lib/hashdiff/util.rb,
lib/hashdiff/version.rb
Overview
This module provides methods to diff two hash, patch and unpatch hash
Constant Summary collapse
- VERSION =
'0.0.3'
Class Method Summary collapse
-
.best_diff(obj1, obj2) ⇒ Array
Best diff two objects, which tries to generate the smallest change set.
-
.diff(obj1, obj2, prefix = "", similarity = 0.8) ⇒ Array
Compute the diff of two hashes.
-
.patch!(obj, changes) ⇒ Object
Apply patch to object.
-
.unpatch!(hash, changes) ⇒ Object
Unpatch an object.
Class Method Details
.best_diff(obj1, obj2) ⇒ Array
Best diff two objects, which tries to generate the smallest change set.
HashDiff.best_diff is only meaningful in case of comparing two objects which includes similar objects in array.
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# File 'lib/hashdiff/diff.rb', line 20 def self.best_diff(obj1, obj2) diffs_1 = diff(obj1, obj2, "", 0.3) diffs_2 = diff(obj1, obj2, "", 0.5) diffs_3 = diff(obj1, obj2, "", 0.8) diffs = diffs_1.size < diffs_2.size ? diffs_1 : diffs_2 diffs = diffs.size < diffs_3.size ? diffs : diffs_3 end |
.diff(obj1, obj2, prefix = "", similarity = 0.8) ⇒ Array
Compute the diff of two hashes
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# File 'lib/hashdiff/diff.rb', line 48 def self.diff(obj1, obj2, prefix = "", similarity = 0.8) if obj1.nil? and obj2.nil? return [] end if obj1.nil? return [['-', prefix, nil]] + changed(obj2, '+', prefix) end if obj2.nil? return changed(obj1, '-', prefix) + [['+', prefix, nil]] end if !(obj1.is_a?(Array) and obj2.is_a?(Array)) and !(obj1.is_a?(Hash) and obj2.is_a?(Hash)) and !(obj1.is_a?(obj2.class) or obj2.is_a?(obj1.class)) return changed(obj1, '-', prefix) + changed(obj2, '+', prefix) end result = [] if obj1.is_a?(Array) changeset = diff_array(obj1, obj2, similarity) do |lcs| # use a's index for similarity lcs.each do |pair| result.concat(diff(obj1[pair[0]], obj2[pair[1]], "#{prefix}[#{pair[0]}]", similarity)) end end changeset.each do |change| if change[0] == '-' result.concat(changed(change[2], '-', "#{prefix}[#{change[1]}]")) elsif change[0] == '+' result.concat(changed(change[2], '+', "#{prefix}[#{change[1]}]")) end end elsif obj1.is_a?(Hash) prefix = prefix.empty? ? "" : "#{prefix}." deleted_keys = [] common_keys = [] obj1.each do |k, v| if obj2.key?(k) common_keys << k else deleted_keys << k end end # add deleted properties deleted_keys.each {|k| result.concat(changed(obj1[k], '-', "#{prefix}#{k}")) } # recursive comparison for common keys common_keys.each {|k| result.concat(diff(obj1[k], obj2[k], "#{prefix}#{k}", similarity)) } # added properties obj2.each do |k, v| unless obj1.key?(k) result.concat(changed(obj2[k], '+', "#{prefix}#{k}")) end end else return [] if obj1 == obj2 return [['~', prefix, obj1, obj2]] end result end |
.patch!(obj, changes) ⇒ Object
Apply patch to object
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# File 'lib/hashdiff/patch.rb', line 14 def self.patch!(obj, changes) changes.each do |change| parts = decode_property_path(change[1]) last_part = parts.last dest_node = node(obj, parts[0, parts.size-1]) if change[0] == '+' if dest_node == nil parent_key = parts[parts.size-2] parent_node = node(obj, parts[0, parts.size-2]) if last_part.is_a?(Fixnum) dest_node = parent_node[parent_key] = [] else dest_node = parent_node[parent_key] = {} end end if last_part.is_a?(Fixnum) dest_node.insert(last_part, change[2]) else dest_node[last_part] = change[2] end elsif change[0] == '-' if last_part.is_a?(Fixnum) dest_node.delete_at(last_part) else dest_node.delete(last_part) end elsif change[0] == '~' dest_node[last_part] = change[3] end end obj end |
.unpatch!(hash, changes) ⇒ Object
Unpatch an object
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# File 'lib/hashdiff/patch.rb', line 59 def self.unpatch!(hash, changes) changes.reverse_each do |change| parts = decode_property_path(change[1]) last_part = parts.last dest_node = node(hash, parts[0, parts.size-1]) if change[0] == '+' if last_part.is_a?(Fixnum) dest_node.delete_at(last_part) else dest_node.delete(last_part) end elsif change[0] == '-' if dest_node == nil parent_key = parts[parts.size-2] parent_node = node(hash, parts[0, parts.size-2]) if last_part.is_a?(Fixnum) dest_node = parent_node[parent_key] = [] else dest_node = parent_node[parent_key] = {} end end if last_part.is_a?(Fixnum) dest_node.insert(last_part, change[2]) else dest_node[last_part] = change[2] end elsif change[0] == '~' dest_node[last_part] = change[2] end end hash end |