Merge branch 'master' into docs_select_version_to_install

7 files changed, 473 insertions, 48 deletions

diff --git a/lib/gitlab/diff/file.rb b/lib/gitlab/diff/file.rb
index 79061cd0141..d2e85cabf72 100644
--- a/lib/gitlab/diff/file.rb
+++ b/lib/gitlab/diff/file.rb
@@ -1,18 +1,39 @@
 module Gitlab
   module Diff
     class File
-      attr_reader :diff
+      attr_reader :diff, :diff_refs
 
       delegate :new_file, :deleted_file, :renamed_file,
         :old_path, :new_path, to: :diff, prefix: false
 
-      def initialize(diff)
+      def initialize(diff, diff_refs)
         @diff = diff
+        @diff_refs = diff_refs
+      end
+
+      def old_ref
+        diff_refs[0] if diff_refs
+      end
+
+      def new_ref
+        diff_refs[1] if diff_refs
       end
 
       # Array of Gitlab::DIff::Line objects
       def diff_lines
-        @lines ||= parser.parse(raw_diff.lines)
+        @lines ||= parser.parse(raw_diff.each_line).to_a
+      end
+
+      def too_large?
+        diff.too_large?
+      end
+
+      def highlighted_diff_lines
+        Gitlab::Diff::Highlight.new(self).highlight
+      end
+
+      def parallel_diff_lines
+        Gitlab::Diff::ParallelDiff.new(self).parallelize
       end
 
       def mode_changed?
diff --git a/lib/gitlab/diff/highlight.rb b/lib/gitlab/diff/highlight.rb
new file mode 100644
index 00000000000..9429b3ff88d
--- /dev/null
+++ b/lib/gitlab/diff/highlight.rb
@@ -0,0 +1,77 @@
+module Gitlab
+  module Diff
+    class Highlight
+      attr_reader :diff_file, :diff_lines, :raw_lines
+
+      delegate :old_path, :new_path, :old_ref, :new_ref, to: :diff_file, prefix: :diff
+
+      def initialize(diff_lines)
+        if diff_lines.is_a?(Gitlab::Diff::File)
+          @diff_file = diff_lines
+          @diff_lines = @diff_file.diff_lines
+        else
+          @diff_lines = diff_lines
+        end
+        @raw_lines = @diff_lines.map(&:text)
+      end
+
+      def highlight
+        @diff_lines.map.with_index do |diff_line, i|
+          diff_line = diff_line.dup
+          # ignore highlighting for "match" lines
+          next diff_line if diff_line.type == 'match' || diff_line.type == 'nonewline'
+
+          rich_line = highlight_line(diff_line) || diff_line.text
+
+          if line_inline_diffs = inline_diffs[i]
+            rich_line = InlineDiffMarker.new(diff_line.text, rich_line).mark(line_inline_diffs)
+          end
+
+          diff_line.text = rich_line
+
+          diff_line
+        end
+      end
+
+      private
+
+      def highlight_line(diff_line)
+        return unless diff_file && diff_file.diff_refs
+
+        line_prefix = diff_line.text.match(/\A(.)/) ? $1 : ' '
+
+        case diff_line.type
+        when 'new', nil
+          rich_line = new_lines[diff_line.new_pos - 1]
+        when 'old'
+          rich_line = old_lines[diff_line.old_pos - 1]
+        end
+
+        # Only update text if line is found. This will prevent
+        # issues with submodules given the line only exists in diff content.
+        "#{line_prefix}#{rich_line}".html_safe if rich_line
+      end
+
+      def inline_diffs
+        @inline_diffs ||= InlineDiff.for_lines(@raw_lines)
+      end
+
+      def old_lines
+        return unless diff_file
+        @old_lines ||= Gitlab::Highlight.highlight_lines(*processing_args(:old))
+      end
+
+      def new_lines
+        return unless diff_file
+        @new_lines ||= Gitlab::Highlight.highlight_lines(*processing_args(:new))
+      end
+
+      def processing_args(version)
+        ref  = send("diff_#{version}_ref")
+        path = send("diff_#{version}_path")
+
+        [ref.project.repository, ref.id, path]
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/diff/inline_diff.rb b/lib/gitlab/diff/inline_diff.rb
new file mode 100644
index 00000000000..789c14518b0
--- /dev/null
+++ b/lib/gitlab/diff/inline_diff.rb
@@ -0,0 +1,88 @@
+module Gitlab
+  module Diff
+    class InlineDiff
+      attr_accessor :old_line, :new_line, :offset
+
+      def self.for_lines(lines)
+        local_edit_indexes = self.find_local_edits(lines)
+
+        inline_diffs = []
+
+        local_edit_indexes.each do |index|
+          old_index = index
+          new_index = index + 1
+          old_line = lines[old_index]
+          new_line = lines[new_index]
+
+          old_diffs, new_diffs = new(old_line, new_line, offset: 1).inline_diffs
+
+          inline_diffs[old_index] = old_diffs
+          inline_diffs[new_index] = new_diffs
+        end
+
+        inline_diffs
+      end
+
+      def initialize(old_line, new_line, offset: 0)
+        @old_line = old_line[offset..-1]
+        @new_line = new_line[offset..-1]
+        @offset = offset
+      end
+
+      def inline_diffs
+        # Skip inline diff if empty line was replaced with content
+        return if old_line == ""
+
+        lcp = longest_common_prefix(old_line, new_line)
+        lcs = longest_common_suffix(old_line[lcp..-1], new_line[lcp..-1])
+
+        lcp += offset
+        old_length = old_line.length + offset
+        new_length = new_line.length + offset
+
+        old_diff_range = lcp..(old_length - lcs - 1)
+        new_diff_range = lcp..(new_length - lcs - 1)
+
+        old_diffs = [old_diff_range] if old_diff_range.begin <= old_diff_range.end
+        new_diffs = [new_diff_range] if new_diff_range.begin <= new_diff_range.end
+
+        [old_diffs, new_diffs]
+      end
+
+      private
+
+      def self.find_local_edits(lines)
+        line_prefixes = lines.map { |line| line.match(/\A([+-])/) ? $1 : ' ' }
+        joined_line_prefixes = " #{line_prefixes.join} "
+
+        offset = 0
+        local_edit_indexes = []
+        while index = joined_line_prefixes.index(" -+ ", offset)
+          local_edit_indexes << index
+          offset = index + 1
+        end
+
+        local_edit_indexes
+      end
+
+      def longest_common_prefix(a, b)
+        max_length = [a.length, b.length].max
+
+        length = 0
+        (0..max_length - 1).each do |pos|
+          old_char = a[pos]
+          new_char = b[pos]
+
+          break if old_char != new_char
+          length += 1
+        end
+
+        length
+      end
+
+      def longest_common_suffix(a, b)
+        longest_common_prefix(a.reverse, b.reverse)
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/diff/inline_diff_marker.rb b/lib/gitlab/diff/inline_diff_marker.rb
new file mode 100644
index 00000000000..dccb717e95d
--- /dev/null
+++ b/lib/gitlab/diff/inline_diff_marker.rb
@@ -0,0 +1,115 @@
+module Gitlab
+  module Diff
+    class InlineDiffMarker
+      attr_accessor :raw_line, :rich_line
+
+      def initialize(raw_line, rich_line = raw_line)
+        @raw_line = raw_line
+        @rich_line = ERB::Util.html_escape(rich_line)
+      end
+
+      def mark(line_inline_diffs)
+        return rich_line unless line_inline_diffs
+
+        marker_ranges = []
+        line_inline_diffs.each do |inline_diff_range|
+          # Map the inline-diff range based on the raw line to character positions in the rich line
+          inline_diff_positions = position_mapping[inline_diff_range].flatten
+          # Turn the array of character positions into ranges
+          marker_ranges.concat(collapse_ranges(inline_diff_positions))
+        end
+
+        offset = 0
+        # Mark each range
+        marker_ranges.each_with_index do |range, i|
+          class_names = ["idiff"]
+          class_names << "left"   if i == 0
+          class_names << "right"  if i == marker_ranges.length - 1
+
+          offset = insert_around_range(rich_line, range, "<span class='#{class_names.join(" ")}'>", "</span>", offset)
+        end
+
+        rich_line.html_safe
+      end
+
+      private
+
+      # Mapping of character positions in the raw line, to the rich (highlighted) line
+      def position_mapping
+        @position_mapping ||= begin
+          mapping = []
+          rich_pos = 0
+          (0..raw_line.length).each do |raw_pos|
+            rich_char = rich_line[rich_pos]
+
+            # The raw and rich lines are the same except for HTML tags,
+            # so skip over any `<...>` segment
+            while rich_char == '<'
+              until rich_char == '>'
+                rich_pos += 1
+                rich_char = rich_line[rich_pos]
+              end
+
+              rich_pos += 1
+              rich_char = rich_line[rich_pos]
+            end
+
+            # multi-char HTML entities in the rich line correspond to a single character in the raw line
+            if rich_char == '&'
+              multichar_mapping = [rich_pos]
+              until rich_char == ';'
+                rich_pos += 1
+                multichar_mapping << rich_pos
+                rich_char = rich_line[rich_pos]
+              end
+
+              mapping[raw_pos] = multichar_mapping
+            else
+              mapping[raw_pos] = rich_pos
+            end
+
+            rich_pos += 1
+          end
+
+          mapping
+        end
+      end
+
+      # Takes an array of integers, and returns an array of ranges covering the same integers
+      def collapse_ranges(positions)
+        return [] if positions.empty?
+        ranges = []
+
+        start = prev = positions[0]
+        range = start..prev
+        positions[1..-1].each do |pos|
+          if pos == prev + 1
+            range = start..pos
+            prev = pos
+          else
+            ranges << range
+            start = prev = pos
+            range = start..prev
+          end
+        end
+        ranges << range
+
+        ranges
+      end
+
+      # Inserts tags around the characters identified by the given range
+      def insert_around_range(text, range, before, after, offset = 0)
+        # Just to be sure
+        return offset if offset + range.end + 1 > text.length
+
+        text.insert(offset + range.begin, before)
+        offset += before.length
+
+        text.insert(offset + range.end + 1, after)
+        offset += after.length
+
+        offset
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/diff/line.rb b/lib/gitlab/diff/line.rb
index 0072194606e..03730b435ad 100644
--- a/lib/gitlab/diff/line.rb
+++ b/lib/gitlab/diff/line.rb
@@ -1,7 +1,8 @@
 module Gitlab
   module Diff
     class Line
-      attr_reader :type, :text, :index, :old_pos, :new_pos
+      attr_reader :type, :index, :old_pos, :new_pos
+      attr_accessor :text
 
       def initialize(text, type, index, old_pos, new_pos)
         @text, @type, @index = text, type, index
diff --git a/lib/gitlab/diff/parallel_diff.rb b/lib/gitlab/diff/parallel_diff.rb
new file mode 100644
index 00000000000..74f9b3c050a
--- /dev/null
+++ b/lib/gitlab/diff/parallel_diff.rb
@@ -0,0 +1,119 @@
+module Gitlab
+  module Diff
+    class ParallelDiff
+      attr_accessor :diff_file
+
+      def initialize(diff_file)
+        @diff_file = diff_file
+      end
+
+      def parallelize
+        lines = []
+        skip_next = false
+
+        highlighted_diff_lines = diff_file.highlighted_diff_lines
+        highlighted_diff_lines.each do |line|
+          full_line = line.text
+          type = line.type
+          line_code = generate_line_code(diff_file.file_path, line)
+          line_new = line.new_pos
+          line_old = line.old_pos
+
+          next_line = diff_file.next_line(line.index)
+
+          if next_line
+            next_line = highlighted_diff_lines[next_line.index]
+            next_line_code = generate_line_code(diff_file.file_path, next_line)
+            next_type = next_line.type
+            next_line = next_line.text
+          end
+
+          case type
+          when 'match', nil
+            # line in the right panel is the same as in the left one
+            lines << {
+              left: {
+                type:       type,
+                number:     line_old,
+                text:       full_line,
+                line_code:  line_code,
+              },
+              right: {
+                type:       type,
+                number:     line_new,
+                text:       full_line,
+                line_code:  line_code
+              }
+            }
+          when 'old'
+            case next_type
+            when 'new'
+              # Left side has text removed, right side has text added
+              lines << {
+                left: {
+                  type:       type,
+                  number:     line_old,
+                  text:       full_line,
+                  line_code:  line_code,
+                },
+                right: {
+                  type:       next_type,
+                  number:     line_new,
+                  text:       next_line,
+                  line_code:  next_line_code
+                }
+              }
+              skip_next = true
+            when 'old', 'nonewline', nil
+              # Left side has text removed, right side doesn't have any change
+              # No next line code, no new line number, no new line text
+              lines << {
+                left: {
+                  type:       type,
+                  number:     line_old,
+                  text:       full_line,
+                  line_code:  line_code,
+                },
+                right: {
+                  type:       next_type,
+                  number:     nil,
+                  text:       "",
+                  line_code:  nil
+                }
+              }
+            end
+          when 'new'
+            if skip_next
+              # Change has been already included in previous line so no need to do it again
+              skip_next = false
+              next
+            else
+              # Change is only on the right side, left side has no change
+              lines << {
+                left: {
+                  type:       nil,
+                  number:     nil,
+                  text:       "",
+                  line_code:  line_code,
+                },
+                right: {
+                  type:       type,
+                  number:     line_new,
+                  text:       full_line,
+                  line_code:  line_code
+                }
+              }
+            end
+          end
+        end
+        lines
+      end
+
+      private
+
+      def generate_line_code(file_path, line)
+        Gitlab::Diff::LineCode.generate(file_path, line.new_pos, line.old_pos)
+      end
+    end
+  end
+end
diff --git a/lib/gitlab/diff/parser.rb b/lib/gitlab/diff/parser.rb
index 7015fe36c3d..d0815fc7eea 100644
--- a/lib/gitlab/diff/parser.rb
+++ b/lib/gitlab/diff/parser.rb
@@ -4,49 +4,56 @@ module Gitlab
       include Enumerable
 
       def parse(lines)
+        return [] if lines.blank?
+
         @lines = lines
-        lines_obj = []
         line_obj_index = 0
         line_old = 1
         line_new = 1
         type = nil
 
-        lines_arr = ::Gitlab::InlineDiff.processing lines
-
-        lines_arr.each do |line|
-          next if filename?(line)
-
-          full_line = html_escape(line.gsub(/\n/, ''))
-          full_line = ::Gitlab::InlineDiff.replace_markers full_line
-
-          if line.match(/^@@ -/)
-            type = "match"
-
-            line_old = line.match(/\-[0-9]*/)[0].to_i.abs rescue 0
-            line_new = line.match(/\+[0-9]*/)[0].to_i.abs rescue 0
-
-            next if line_old <= 1 && line_new <= 1 #top of file
-            lines_obj << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new)
-            line_obj_index += 1
-            next
-          else
-            type = identification_type(line)
-            lines_obj << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new)
-            line_obj_index += 1
-          end
-
-
-          if line[0] == "+"
-            line_new += 1
-          elsif line[0] == "-"
-            line_old += 1
-          else
-            line_new += 1
-            line_old += 1
+        # By returning an Enumerator we make it possible to search for a single line (with #find)
+        # without having to instantiate all the others that come after it.
+        Enumerator.new do |yielder|
+          @lines.each do |line|
+            next if filename?(line)
+  
+            full_line = line.gsub(/\n/, '')
+  
+            if line.match(/^@@ -/)
+              type = "match"
+  
+              line_old = line.match(/\-[0-9]*/)[0].to_i.abs rescue 0
+              line_new = line.match(/\+[0-9]*/)[0].to_i.abs rescue 0
+  
+              next if line_old <= 1 && line_new <= 1 #top of file
+              yielder << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new)
+              line_obj_index += 1
+              next
+            elsif line[0] == '\\'
+              type = 'nonewline'
+              yielder << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new)
+              line_obj_index += 1
+            else
+              type = identification_type(line)
+              yielder << Gitlab::Diff::Line.new(full_line, type, line_obj_index, line_old, line_new)
+              line_obj_index += 1
+            end
+  
+  
+            case line[0]
+            when "+"
+              line_new += 1
+            when "-"
+              line_old += 1
+            when "\\"
+              # No increment
+            else
+              line_new += 1
+              line_old += 1
+            end
           end
         end
-
-        lines_obj
       end
 
       def empty?
@@ -56,24 +63,21 @@ module Gitlab
       private
 
       def filename?(line)
-        line.start_with?('--- /dev/null', '+++ /dev/null', '--- a', '+++ b',
-                         '--- /tmp/diffy', '+++ /tmp/diffy')
+        line.start_with?( '--- /dev/null', '+++ /dev/null', '--- a', '+++ b',
+                          '+++ a', # The line will start with `+++ a` in the reverse diff of an orphan commit
+                          '--- /tmp/diffy', '+++ /tmp/diffy')
       end
 
       def identification_type(line)
-        if line[0] == "+"
+        case line[0]
+        when "+"
           "new"
-        elsif line[0] == "-"
+        when "-"
           "old"
         else
           nil
         end
       end
-
-      def html_escape(str)
-        replacements = { '&' => '&amp;', '>' => '&gt;', '<' => '&lt;', '"' => '&quot;', "'" => '&#39;' }
-        str.gsub(/[&"'><]/, replacements)
-      end
     end
   end
 end