item_rep.rb in nanoc3-3.1.0b2

- old
+ new

@@ -190,10 +190,15 @@
         snapshot_name ||= :pre
       else
         snapshot_name ||= :last
       end
 
+      # Check presence of snapshot
+      if @content[snapshot_name].nil?
+        warn "WARNING: The “#{self.item.identifier}” item (rep “#{self.name}”) does not have the requested snapshot named #{snapshot_name.inspect}.\n\n* Make sure that you are requesting the correct snapshot.\n* It is not possible to request the compiled content of a binary item representation; if this item is marked as binary even though you believe it should be textual, you may need to add the extension of this item to the site configuration’s `text_extensions` array.".make_compatible_with_env
+      end
+
       # Get content
       @content[snapshot_name]
     end
 
     # @deprecated Use {Nanoc3::ItemRep#compiled_content} instead.
@@ -331,10 +336,13 @@
 
         # Write
         File.open(self.raw_path, 'w') { |io| io.write(@content[:last]) }
         @written = true
 
+        # Generate diff
+        generate_diff
+
         # Check if file was modified
         @modified = File.read(self.raw_path) != @old_content
       end
     end
 
@@ -344,24 +352,22 @@
     #
     # @return [String, nil] The difference between the old and new compiled
     # content in `diff(1)` format, or nil if there is no previous compiled
     # content
     def diff
-      # Check if content can be diffed
       # TODO allow binary diffs
-      return nil if self.binary?
 
-      # Check if old content exists
-      if @old_content.nil? or self.raw_path.nil?
+      if self.binary?
         nil
       else
-        diff_strings(@old_content, @content[:last])
+         @diff_thread.join if @diff_thread
+        @diff
       end
     end
 
     def inspect
-      "<#{self.class}:0x#{self.object_id.to_s(16)} name=#{self.name} binary=#{self.binary?} item.identifier=#{self.item.identifier}>"
+      "<#{self.class}:0x#{self.object_id.to_s(16)} name=#{self.name} binary=#{self.binary?} raw_path=#{self.raw_path} item.identifier=#{self.item.identifier}>"
     end
 
   private
 
     def filter_named(name)
@@ -388,10 +394,22 @@
 
       # Done
       [ filter, filter_name, filter_args ]
     end
 
+    def generate_diff
+      if @old_content.nil? or self.raw_path.nil?
+        @diff = nil
+      else
+        @diff_thread = Thread.new do
+          @diff = diff_strings(@old_content, @content[:last])
+          sleep 2
+          @diff_thread = nil
+        end
+      end
+    end
+
     def diff_strings(a, b)
       # TODO Rewrite this string-diffing method in pure Ruby. It should not
       # use the "diff" executable, because this will most likely not work on
       # operating systems without it, such as Windows.
 
@@ -404,12 +422,14 @@
           # Write files
           old_file.write(a)
           new_file.write(b)
 
           # Diff
-          stdin, stdout, stderr = Open3.popen3('diff', '-u', old_file.path, new_file.path)
-          result = stdout.read
-          result == '' ? nil : result
+          cmd = [ 'diff', '-u', old_file.path, new_file.path ]
+          Open3.popen3(*cmd) do |stdin, stdout, stderr|
+            result = stdout.read
+            return (result == '' ? nil : result)
+          end
         end
       end
     rescue Errno::ENOENT
       warn 'Failed to run `diff`, so no diff with the previously compiled ' \
            'content will be available.'