gitlab-org--gitlab-foss/lib/gitlab/gfm/reference_rewriter.rb

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module Gitlab
module Gfm
##
# Class that unfolds local references in text.
#
# The initializer takes text in Markdown and project this text is valid
# in context of.
#
# `unfold` method tries to find all local references and unfold each of
# those local references to cross reference format, assuming that the
# argument passed to this method is a project that references will be
# viewed from (see `Referable#to_reference method).
#
# Examples:
#
# 'Hello, this issue is related to #123 and
# other issues labeled with ~"label"', will be converted to:
#
# 'Hello, this issue is related to gitlab-org/gitlab-ce#123 and
# other issue labeled with gitlab-org/gitlab-ce~"label"'.
#
# It does respect markdown lexical rules, so text in code block will not be
# replaced, see another example:
#
# 'Merge request for issue #1234, see also link:
# http://gitlab.com/some/link/#1234, and code `puts #1234`' =>
#
# 'Merge request for issue gitlab-org/gitlab-ce#1234, se also link:
# http://gitlab.com/some/link/#1234, and code `puts #1234`'
#
class ReferenceRewriter
RewriteError = Class.new(StandardError)
def initialize(text, source_project, current_user)
@text = text
@source_project = source_project
@current_user = current_user
@original_html = markdown(text)
@pattern = Gitlab::ReferenceExtractor.references_pattern
end
def rewrite(target_project)
return @text unless needs_rewrite?
@text.gsub(@pattern) do |reference|
unfold_reference(reference, Regexp.last_match, target_project)
end
end
def needs_rewrite?
@text =~ @pattern
end
private
def unfold_reference(reference, match, target_project)
before = @text[0...match.begin(0)]
after = @text[match.end(0)..-1]
referable = find_referable(reference)
return reference unless referable
cross_reference = build_cross_reference(referable, target_project)
return reference if reference == cross_reference
if cross_reference.nil?
raise RewriteError, "Unspecified reference detected for #{referable.class.name}"
end
new_text = before + cross_reference + after
substitution_valid?(new_text) ? cross_reference : reference
end
def find_referable(reference)
extractor = Gitlab::ReferenceExtractor.new(@source_project,
@current_user)
extractor.analyze(reference)
extractor.all.first
end
def build_cross_reference(referable, target_project)
if referable.respond_to?(:project)
referable.to_reference(target_project)
else
referable.to_reference(@source_project, target_project: target_project)
end
end
def substitution_valid?(substituted)
@original_html == markdown(substituted)
end
def markdown(text)
Banzai.render(text, project: @source_project, no_original_data: true)
end
end
end
end