Rename GitlabMarkdownHelper -> MarkupHelper

It does more than solely GitLab Markdown, so rename to MarkupHelper.

1 files changed, 211 insertions, 0 deletions

diff --git a/app/helpers/markup_helper.rb b/app/helpers/markup_helper.rb
new file mode 100644
index 00000000000..a10714e81ae
--- /dev/null
+++ b/app/helpers/markup_helper.rb
@@ -0,0 +1,211 @@
+require 'nokogiri'
+
+module MarkupHelper
+  # Use this in places where you would normally use link_to(gfm(...), ...).
+  #
+  # It solves a problem occurring with nested links (i.e.
+  # "<a>outer text <a>gfm ref</a> more outer text</a>"). This will not be
+  # interpreted as intended. Browsers will parse something like
+  # "<a>outer text </a><a>gfm ref</a> more outer text" (notice the last part is
+  # not linked any more). link_to_gfm corrects that. It wraps all parts to
+  # explicitly produce the correct linking behavior (i.e.
+  # "<a>outer text </a><a>gfm ref</a><a> more outer text</a>").
+  def link_to_gfm(body, url, html_options = {})
+    return "" if body.blank?
+
+    context = {
+      project: @project,
+      current_user: (current_user if defined?(current_user)),
+      pipeline: :single_line,
+    }
+    gfm_body = Banzai.render(body, context)
+
+    fragment = Nokogiri::HTML::DocumentFragment.parse(gfm_body)
+    if fragment.children.size == 1 && fragment.children[0].name == 'a'
+      # Fragment has only one node, and it's a link generated by `gfm`.
+      # Replace it with our requested link.
+      text = fragment.children[0].text
+      fragment.children[0].replace(link_to(text, url, html_options))
+    else
+      # Traverse the fragment's first generation of children looking for pure
+      # text, wrapping anything found in the requested link
+      fragment.children.each do |node|
+        next unless node.text?
+        node.replace(link_to(node.text, url, html_options))
+      end
+    end
+
+    # Add any custom CSS classes to the GFM-generated reference links
+    if html_options[:class]
+      fragment.css('a.gfm').add_class(html_options[:class])
+    end
+
+    fragment.to_html.html_safe
+  end
+
+  def markdown(text, context = {})
+    return "" unless text.present?
+
+    context[:project] ||= @project
+
+    html = Banzai.render(text, context)
+    banzai_postprocess(html, context)
+  end
+
+  def markdown_field(object, field)
+    object = object.for_display if object.respond_to?(:for_display)
+    return "" unless object.present?
+
+    html = Banzai.render_field(object, field)
+    banzai_postprocess(html, object.banzai_render_context(field))
+  end
+
+  def asciidoc(text)
+    Gitlab::Asciidoc.render(
+      text,
+      project:      @project,
+      current_user: (current_user if defined?(current_user)),
+
+      # RelativeLinkFilter
+      project_wiki:   @project_wiki,
+      requested_path: @path,
+      ref:            @ref,
+      commit:         @commit
+    )
+  end
+
+  def other_markup(file_name, text)
+    Gitlab::OtherMarkup.render(
+      file_name,
+      text,
+      project:      @project,
+      current_user: (current_user if defined?(current_user)),
+
+      # RelativeLinkFilter
+      project_wiki:   @project_wiki,
+      requested_path: @path,
+      ref:            @ref,
+      commit:         @commit
+    )
+  end
+
+  # Return the first line of +text+, up to +max_chars+, after parsing the line
+  # as Markdown.  HTML tags in the parsed output are not counted toward the
+  # +max_chars+ limit.  If the length limit falls within a tag's contents, then
+  # the tag contents are truncated without removing the closing tag.
+  def first_line_in_markdown(text, max_chars = nil, options = {})
+    md = markdown(text, options).strip
+
+    truncate_visible(md, max_chars || md.length) if md.present?
+  end
+
+  def render_wiki_content(wiki_page)
+    case wiki_page.format
+    when :markdown
+      markdown(wiki_page.content, pipeline: :wiki, project_wiki: @project_wiki, page_slug: wiki_page.slug)
+    when :asciidoc
+      asciidoc(wiki_page.content)
+    else
+      wiki_page.formatted_content.html_safe
+    end
+  end
+
+  # Returns the text necessary to reference `entity` across projects
+  #
+  # project - Project to reference
+  # entity  - Object that responds to `to_reference`
+  #
+  # Examples:
+  #
+  #   cross_project_reference(project, project.issues.first)
+  #   # => 'namespace1/project1#123'
+  #
+  #   cross_project_reference(project, project.merge_requests.first)
+  #   # => 'namespace1/project1!345'
+  #
+  # Returns a String
+  def cross_project_reference(project, entity)
+    if entity.respond_to?(:to_reference)
+      entity.to_reference(project, full: true)
+    else
+      ''
+    end
+  end
+
+  private
+
+  # Return +text+, truncated to +max_chars+ characters, excluding any HTML
+  # tags.
+  def truncate_visible(text, max_chars)
+    doc = Nokogiri::HTML.fragment(text)
+    content_length = 0
+    truncated = false
+
+    doc.traverse do |node|
+      if node.text? || node.content.empty?
+        if truncated
+          node.remove
+          next
+        end
+
+        # Handle line breaks within a node
+        if node.content.strip.lines.length > 1
+          node.content = "#{node.content.lines.first.chomp}..."
+          truncated = true
+        end
+
+        num_remaining = max_chars - content_length
+        if node.content.length > num_remaining
+          node.content = node.content.truncate(num_remaining)
+          truncated = true
+        end
+        content_length += node.content.length
+      end
+
+      truncated = truncate_if_block(node, truncated)
+    end
+
+    doc.to_html
+  end
+
+  # Used by #truncate_visible.  If +node+ is the first block element, and the
+  # text hasn't already been truncated, then append "..." to the node contents
+  # and return true.  Otherwise return false.
+  def truncate_if_block(node, truncated)
+    return true if truncated
+
+    if node.element? && (node.description&.block? || node.matches?('pre > code > .line'))
+      node.inner_html = "#{node.inner_html}..." if node.next_sibling
+      true
+    else
+      truncated
+    end
+  end
+
+  def markdown_toolbar_button(options = {})
+    data = options[:data].merge({ container: "body" })
+    content_tag :button,
+      type: "button",
+      class: "toolbar-btn js-md has-tooltip hidden-xs",
+      tabindex: -1,
+      data: data,
+      title: options[:title],
+      aria: { label: options[:title] } do
+      icon(options[:icon])
+    end
+  end
+
+  # Calls Banzai.post_process with some common context options
+  def banzai_postprocess(html, context = {})
+    context.merge!(
+      current_user:   (current_user if defined?(current_user)),
+
+      # RelativeLinkFilter
+      requested_path: @path,
+      project_wiki:   @project_wiki,
+      ref:            @ref
+    )
+
+    Banzai.post_process(html, context)
+  end
+end