lib/jekyll/zopfli/compressor.rb in jekyll-zopfli-2.3.0 vs lib/jekyll/zopfli/compressor.rb in jekyll-zopfli-2.4.0

@@ -23,11 +23,17 @@
       #   site files ready for compression.
       #
       # @return void
       def self.compress_site(site)
         site.each_site_file do |file|
-          compress_file(file.destination(site.dest), extensions: zippable_extensions(site), replace_file: replace_files(site))
+          next unless regenerate? file.destination(site.dest), site
+
+          compress_file(
+            file.destination(site.dest),
+            extensions: zippable_extensions(site),
+            replace_file: replace_files(site)
+          )
         end
       end
 
       ##
       # Takes a directory path and maps over the files within compressing them
@@ -43,11 +49,19 @@
       #
       # @return void
       def self.compress_directory(dir, site)
         extensions = zippable_extensions(site).join(',')
         files = Dir.glob(dir + "/**/*{#{extensions}}")
-        files.each { |file| compress_file(file, extensions: zippable_extensions(site), replace_file: replace_files(site)) }
+        files.each do |file|
+          next unless regenerate? file, site
+
+          compress_file(
+            file,
+            extensions: zippable_extensions(site),
+            replace_file: replace_files(site)
+          )
+        end
       end
 
       ##
       # Takes a file name and an array of extensions. If the file name extension
       # matches one of the extensions in the array then the file is loaded and
@@ -65,11 +79,11 @@
       #
       # @return void
       def self.compress_file(file_name, extensions: [], replace_file: false)
         return unless extensions.include?(File.extname(file_name))
         zipped = replace_file ? file_name : "#{file_name}.gz"
-        contents = ::Zopfli.deflate(File.read(file_name), format: :gzip)
+        contents = ::Zopfli.deflate(File.binread(file_name), format: :gzip)
         File.open(zipped, "w+") do |file|
           file << contents
         end
         File.utime(File.atime(file_name), File.mtime(file_name), zipped)
       end
@@ -81,9 +95,35 @@
       end
 
       def self.replace_files(site)
         replace_files = site.config.dig('zopfli', 'replace_files')
         replace_files.nil? ? Jekyll::Zopfli::DEFAULT_CONFIG['replace_files'] : replace_files
+      end
+
+      def self.zipped(file_name, replace_file)
+        replace_file ? file_name : "#{file_name}.gz"
+      end
+
+      # Compresses the file if the site is built incrementally and the
+      # source was modified or the compressed file doesn't exist
+      def self.regenerate?(file, site)
+        zipped = zipped(file, replace_files(site))
+
+        # Definitely generate the file if it doesn't exist yet.
+        return true unless File.exist? zipped
+        # If we are replacing files and this file is not a gzip file, then it
+        # has been edited so we need to re-gzip it in place.
+        return !is_already_gzipped?(file) if replace_files(site)
+
+        # If the modified time of the new file is greater than the modified time
+        # of the old file, then we need to regenerate.
+        File.mtime(file) > File.mtime(zipped)
+      end
+
+      # First two bytes of a gzipped file are 1f and 8b. This tests for those
+      # bytes.
+      def self.is_already_gzipped?(file)
+        ["1f", "8b"] == File.read(file, 2).unpack("H2H2")
       end
     end
   end
 end