1 files changed, 55 insertions, 0 deletions
diff --git a/lib/banzai/reference_extractor.rb b/lib/banzai/reference_extractor.rb
new file mode 100644
index 00000000000..2c197d31898
--- /dev/null
+++ b/lib/banzai/reference_extractor.rb
@@ -0,0 +1,55 @@
+require 'banzai'
+
+module Banzai
+  # Extract possible GFM references from an arbitrary String for further processing.
+  class ReferenceExtractor
+    class << self
+      LAZY_KEY = :banzai_reference_extractor_lazy
+
+      def lazy?
+        Thread.current[LAZY_KEY]
+      end
+
+      def lazily(values = nil, &block)
+        return (values || block.call).uniq if lazy?
+
+        begin
+          Thread.current[LAZY_KEY] = true
+
+          values ||= block.call
+
+          Banzai::LazyReference.load(values.uniq).uniq
+        ensure
+          Thread.current[LAZY_KEY] = false
+        end
+      end
+    end
+
+    def initialize
+      @texts = []
+    end
+
+    def analyze(text, context = {})
+      @texts << Renderer.render(text, context)
+    end
+
+    def references(type, context = {})
+      filter = Banzai::Filter["#{type}_reference"]
+
+      context.merge!(
+        pipeline: :reference_extraction,
+
+        # ReferenceGathererFilter
+        reference_filter: filter
+      )
+
+      self.class.lazily do
+        @texts.flat_map do |html|
+          text_context = context.dup
+          result = Renderer.render_result(html, text_context)
+          result[:references][type]
+        end.uniq
+      end
+    end
+  end
+end