Refactor frontmatter parsing

Closes #1603

middleman-core/lib/middleman-core/util/data.rb

@@ -20,116 +20,66 @@ module Middleman
 
       module_function
 
-      YAML_ERRORS = [StandardError]
-
-      # https://github.com/tenderlove/psych/issues/23
-      if defined?(Psych) && defined?(Psych::SyntaxError)
-        YAML_ERRORS << Psych::SyntaxError
-      end
-
       # Get the frontmatter and plain content from a file
       # @param [String] path
       # @return [Array<Hash, String>]
       Contract Pathname, Maybe[Symbol] => [Hash, Maybe[String]]
       def parse(full_path, known_type=nil)
-        data = {}
+        return [{}, nil] if Middleman::Util.binary?(full_path)
-
-        return [data, nil] if ::Middleman::Util.binary?(full_path)
-
-        # Avoid weird race condition when a file is renamed.
-        content = begin
-          File.read(full_path)
-        rescue ::EOFError
-        rescue ::IOError
-        rescue ::Errno::ENOENT
-          ''
-        end
 
+        # Avoid weird race condition when a file is renamed
         begin
-          if content =~ /\A.*coding:/
+          content = File.read(full_path)
-            lines = content.split(/\n/)
+        rescue EOFError, IOError, Errno::ENOENT
-            lines.shift
+          return [{}, nil]
-            content = lines.join("\n")
-          end
-
-          if known_type
-            if known_type == :yaml
-              result = parse_yaml(content, full_path, true)
-            elsif known_type == :json
-              result = parse_json(content, full_path)
-            end
-          else
-            result = parse_yaml(content, full_path, false)
-          end
-
-          return result if result
-        rescue
-          # Probably a binary file, move on
         end
 
-        [data, content]
+        case known_type
+        when :yaml
+          return [parse_yaml(content, full_path), nil]
+        when :json
+          return [parse_json(content, full_path), nil]
+        end
+
+        /
+          (?<start>^[-;]{3})[ ]*\r?\n
+          (?<frontmatter>.*?)[ ]*\r?\n
+          (?<stop>^[-.;]{3})[ ]*\r?\n?
+          (?<additional_content>.*)
+        /mx =~ content
+
+        return [{}, content] unless frontmatter
+
+        case [start, stop]
+        when %w[--- ---], %w[--- ...]
+          [parse_yaml(frontmatter, full_path), additional_content]
+        when %w[;;; ;;;]
+          [parse_json(frontmatter, full_path), additional_content]
+        else
+          [{}, content]
+        end
       end
 
       # Parse YAML frontmatter out of a string
       # @param [String] content
       # @return [Array<Hash, String>]
-      Contract String, Pathname, Bool => Maybe[[Hash, String]]
+      Contract String, Pathname, Bool => Hash
-      def parse_yaml(content, full_path, require_yaml=false)
+      def parse_yaml(content, full_path)
-        total_delims = content.scan(/^(?:---|\.\.\.)\s*(?:\n|$)/).length
+        map_value(YAML.load(content))
-        has_first_line_delim = !content.match(/\A(---\s*(?:\n|$))/).nil?
+      rescue StandardError, Psych::SyntaxError => error
-        # has_closing_delim = (total_delims > 1 && has_first_line_delim) || (!has_first_line_delim && total_delims == 1)
+        warn "YAML Exception parsing #{full_path}: #{error.message}"
-
+        {}
-        parts = content.split(/^(?:---|\.\.\.)\s*(?:\n|$)/)
-        parts.shift if parts[0].empty?
-
-        yaml_string = nil
-        additional_content = nil
-
-        if require_yaml
-          yaml_string = parts[0]
-          additional_content = parts[1]
-        else
-          if total_delims > 1
-            if has_first_line_delim
-              yaml_string = parts[0]
-              additional_content = parts[1]
-            else
-              additional_content = content
-            end
-          else
-            additional_content = parts[0]
-          end
-        end
-
-        return [{}, additional_content] if yaml_string.nil?
-
-        begin
-          data = map_value(::YAML.load(yaml_string) || {})
-        rescue *YAML_ERRORS => e
-          $stderr.puts "YAML Exception parsing #{full_path}: #{e.message}"
-          return nil
-        end
-
-        [data, additional_content]
-      rescue
-        [{}, additional_content]
       end
 
       # Parse JSON frontmatter out of a string
       # @param [String] content
       # @return [Array<Hash, String>]
-      Contract String, Pathname => Maybe[[Hash, String]]
+      Contract String, Pathname => Hash
       def parse_json(content, full_path)
-        begin
+        map_value(JSON.parse(content))
-          data = map_value(::JSON.parse(content))
+      rescue StandardError => error
-        rescue => e
+        warn "JSON Exception parsing #{full_path}: #{error.message}"
-          $stderr.puts "JSON Exception parsing #{full_path}: #{e.message}"
+        {}
-          return nil
-        end
-
-        [data, nil]
-      rescue
-        [{}, nil]
       end
 
       def symbolize_recursive(hash)