1 files changed, 82 insertions, 0 deletions
diff --git a/lib/banzai/redactor.rb b/lib/banzai/redactor.rb
new file mode 100644
index 00000000000..0df3a72d1c4
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+++ b/lib/banzai/redactor.rb
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+module Banzai
+  # Class for removing Markdown references a certain user is not allowed to
+  # view.
+  class Redactor
+    attr_reader :user, :project
+
+    # project - A Project to use for redacting links.
+    # user - The currently logged in user (if any).
+    def initialize(project, user = nil)
+      @project = project
+      @user = user
+    end
+
+    # Redacts the references in the given Array of documents.
+    #
+    # This method modifies the given documents in-place.
+    #
+    # documents - A list of HTML documents containing references to redact.
+    #
+    # Returns the documents passed as the first argument.
+    def redact(documents)
+      all_document_nodes = document_nodes(documents)
+
+      redact_document_nodes(all_document_nodes)
+    end
+
+    # Redacts the given node documents
+    #
+    # data - An Array of a Hashes mapping an HTML document to nodes to redact.
+    def redact_document_nodes(all_document_nodes)
+      all_nodes = all_document_nodes.map { |x| x[:nodes] }.flatten
+      visible = nodes_visible_to_user(all_nodes)
+      metadata = []
+
+      all_document_nodes.each do |entry|
+        nodes_for_document = entry[:nodes]
+        doc_data = { document: entry[:document], visible_reference_count: nodes_for_document.count }
+        metadata << doc_data
+
+        nodes_for_document.each do |node|
+          next if visible.include?(node)
+
+          doc_data[:visible_reference_count] -= 1
+          # The reference should be replaced by the original text,
+          # which is not always the same as the rendered text.
+          text = node.attr('data-original') || node.text
+          node.replace(text)
+        end
+      end
+
+      metadata
+    end
+
+    # Returns the nodes visible to the current user.
+    #
+    # nodes - The input nodes to check.
+    #
+    # Returns a new Array containing the visible nodes.
+    def nodes_visible_to_user(nodes)
+      per_type = Hash.new { |h, k| h[k] = [] }
+      visible = Set.new
+
+      nodes.each do |node|
+        per_type[node.attr('data-reference-type')] << node
+      end
+
+      per_type.each do |type, nodes|
+        parser = Banzai::ReferenceParser[type].new(project, user)
+
+        visible.merge(parser.nodes_visible_to_user(user, nodes))
+      end
+
+      visible
+    end
+
+    def document_nodes(documents)
+      documents.map do |document|
+        { document: document, nodes: Querying.css(document, 'a.gfm[data-reference-type]') }
+      end
+    end
+  end
+end