128 lines
4.4 KiB
Ruby
128 lines
4.4 KiB
Ruby
# frozen_string_literal: true
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require 'rouge/plugins/common_mark'
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require 'asciidoctor/extensions/asciidoctor_kroki/version'
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require 'asciidoctor/extensions/asciidoctor_kroki/extension'
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# Generated HTML is transformed back to GFM by app/assets/javascripts/behaviors/markdown/nodes/code_block.js
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module Banzai
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module Filter
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# HTML Filter to highlight fenced code blocks
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#
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class SyntaxHighlightFilter < HTML::Pipeline::Filter
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include OutputSafety
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LANG_PARAMS_DELIMITER = ':'
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LANG_PARAMS_ATTR = 'data-lang-params'
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CSS = 'pre:not([data-math-style]):not([data-mermaid-style]):not([data-kroki-style]) > code:only-child'
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XPATH = Gitlab::Utils::Nokogiri.css_to_xpath(CSS).freeze
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def call
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doc.xpath(XPATH).each do |node|
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highlight_node(node)
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end
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doc
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end
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def highlight_node(node)
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css_classes = +'code highlight js-syntax-highlight'
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lang, lang_params = parse_lang_params(node)
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sourcepos = node.parent.attr('data-sourcepos')
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retried = false
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if use_rouge?(lang)
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lexer = lexer_for(lang)
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language = lexer.tag
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else
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lexer = Rouge::Lexers::PlainText.new
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language = lang
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end
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begin
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code = Rouge::Formatters::HTMLGitlab.format(lex(lexer, node.text), tag: language)
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css_classes << " language-#{language}" if language
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rescue StandardError
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# Gracefully handle syntax highlighter bugs/errors to ensure users can
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# still access an issue/comment/etc. First, retry with the plain text
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# filter. If that fails, then just skip this entirely, but that would
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# be a pretty bad upstream bug.
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return if retried
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language = nil
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lexer = Rouge::Lexers::PlainText.new
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retried = true
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retry
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end
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sourcepos_attr = sourcepos ? "data-sourcepos=\"#{escape_once(sourcepos)}\"" : ''
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highlighted = %(<div class="gl-relative markdown-code-block js-markdown-code"><pre #{sourcepos_attr} class="#{css_classes}"
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lang="#{language}"
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#{lang != language ? "data-canonical-lang=\"#{escape_once(lang)}\"" : ""}
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#{lang_params}
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v-pre="true"><code>#{code}</code></pre><copy-code></copy-code></div>)
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# Extracted to a method to measure it
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replace_parent_pre_element(node, highlighted)
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end
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private
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def parse_lang_params(node)
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node = node.parent
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# Commonmarker's FULL_INFO_STRING render option works with the space delimiter.
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# But the current behavior of GitLab's markdown renderer is different - it grabs everything as the single
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# line, including language and its options. To keep backward compatibility, we have to parse the old format and
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# merge with the new one.
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#
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# Behaviors before separating language and its parameters:
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# Old ones:
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# "```ruby with options```" -> '<pre><code lang="ruby with options">'.
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# "```ruby:with:options```" -> '<pre><code lang="ruby:with:options">'.
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#
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# New ones:
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# "```ruby with options```" -> '<pre><code lang="ruby" data-meta="with options">'.
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# "```ruby:with:options```" -> '<pre><code lang="ruby:with:options">'.
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language = node.attr('lang')
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return unless language
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language, language_params = language.split(LANG_PARAMS_DELIMITER, 2)
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language_params = [node.attr('data-meta'), language_params].compact.join(' ')
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formatted_language_params = format_language_params(language_params)
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[language, formatted_language_params]
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end
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# Separate method so it can be instrumented.
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def lex(lexer, code)
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lexer.lex(code)
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end
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def lexer_for(language)
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(Rouge::Lexer.find(language) || Rouge::Lexers::PlainText).new
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end
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# Replace the parent `pre` element with the entire highlighted block
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def replace_parent_pre_element(node, highlighted)
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node.parent.replace(highlighted)
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end
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def use_rouge?(language)
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(%w(math suggestion) + ::AsciidoctorExtensions::Kroki::SUPPORTED_DIAGRAM_NAMES).exclude?(language)
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end
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def format_language_params(language_params)
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return if language_params.blank?
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%(#{LANG_PARAMS_ATTR}="#{escape_once(language_params)}")
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end
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end
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end
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end
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