From 70a2c42a5eef1dab2b7ab75e3c7f6ffc8c8c1959 Mon Sep 17 00:00:00 2001
From: Patrick Spek <p.spek@tyil.nl>
Date: Fri, 5 Feb 2021 09:55:25 +0100
Subject: Move source files into src

---
 src/_plugins/highlight.rb | 127 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 127 insertions(+)
 create mode 100644 src/_plugins/highlight.rb

(limited to 'src/_plugins/highlight.rb')

diff --git a/src/_plugins/highlight.rb b/src/_plugins/highlight.rb
new file mode 100644
index 0000000..d59140c
--- /dev/null
+++ b/src/_plugins/highlight.rb
@@ -0,0 +1,127 @@
+# frozen_string_literal: true
+
+module Jekyll
+  module Tags
+    class HighlightBlock < Liquid::Block
+      include Liquid::StandardFilters
+
+      def initialize(tag_name, markup, tokens)
+        super
+
+        opts = markup.split
+        @opts = Hash.new
+        @lang = opts.shift.downcase
+
+        opts.each do |opt|
+          if opt.include?("=")
+            parts = opt.split("=", 2)
+
+            @opts[parts[0]] = parts[1]
+          end
+
+          @opts[opt] = true
+        end
+      end
+
+      def render(context)
+        prefix = context["highlighter_prefix"] || ""
+        suffix = context["highlighter_suffix"] || ""
+        code = super.to_s.gsub(%r!\A(\n|\r)+|(\n|\r)+\z!, "")
+
+        is_safe = !!context.registers[:site].safe
+
+        output =
+          case context.registers[:site].highlighter
+          when "pygments"
+            render_pygments(code, is_safe)
+          when "rouge"
+            render_rouge(code)
+          else
+            render_codehighlighter(code)
+          end
+
+        rendered_output = add_code_tag(output)
+        prefix + rendered_output + suffix
+      end
+
+      def sanitized_opts(opts, is_safe)
+        if is_safe
+          Hash[[
+            [:startinline, opts.fetch(:startinline, nil)],
+            [:hl_lines,    opts.fetch(:hl_lines, nil)],
+            [:linenos,     opts.fetch(:linenos, nil)],
+            [:encoding,    opts.fetch(:encoding, "utf-8")],
+            [:cssclass,    opts.fetch(:cssclass, nil)],
+          ].reject { |f| f.last.nil? }]
+        else
+          opts
+        end
+      end
+
+      private
+
+      def render_pygments(code, is_safe)
+        Jekyll::External.require_with_graceful_fail("pygments") unless defined?(Pygments)
+
+        highlighted_code = Pygments.highlight(
+          code,
+          :lexer   => @lang,
+          :options => sanitized_opts(@highlight_options, is_safe)
+        )
+
+        if highlighted_code.nil?
+          Jekyll.logger.error <<~MSG
+            There was an error highlighting your code:
+
+            #{code}
+
+            While attempting to convert the above code, Pygments.rb returned an unacceptable value.
+            This is usually a timeout problem solved by running `jekyll build` again.
+          MSG
+          raise ArgumentError, "Pygments.rb returned an unacceptable value "\
+          "when attempting to highlight some code."
+        end
+
+        highlighted_code.sub('<div class="highlight"><pre>', "").sub("</pre></div>", "")
+      end
+
+      def render_rouge(code)
+        require "rouge"
+        formatter = ::Rouge::Formatters::HTMLLegacy.new(
+          :line_numbers => @highlight_options[:linenos],
+          :wrap         => false,
+          :css_class    => "highlight",
+          :gutter_class => "gutter",
+          :code_class   => "code"
+        )
+        lexer = ::Rouge::Lexer.find_fancy(@lang, code) || Rouge::Lexers::PlainText
+        formatter.format(lexer.lex(code))
+      end
+
+      def render_codehighlighter(code)
+        h(code).strip
+      end
+
+      def add_code_tag(code)
+        code_attributes = [
+          "class=\"language-#{@lang.to_s.tr("+", "-")}\"",
+          "data-lang=\"#{@lang}\"",
+        ].join(" ")
+
+        output = "<figure class=\"highlight\"><pre><code #{code_attributes}>"
+        output += code.chomp
+        output += "</code></pre>"
+
+        if @opts["tio"]
+          output += "<div class=\"code-link\"><a href=\"#{@opts["tio"]}\" target=\"_blank\">Run this code</a></div>"
+        end
+
+        output += "</figure>"
+
+        output
+      end
+    end
+  end
+end
+
+Liquid::Template.register_tag("highlight", Jekyll::Tags::HighlightBlock)
-- 
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