1 files changed, 67 insertions, 0 deletions
diff --git a/storage/mroonga/vendor/groonga/lib/mrb/scripts/expression_tree/binary_operation.rb b/storage/mroonga/vendor/groonga/lib/mrb/scripts/expression_tree/binary_operation.rb
new file mode 100644
index 00000000..d59c65c7
--- /dev/null
+++ b/storage/mroonga/vendor/groonga/lib/mrb/scripts/expression_tree/binary_operation.rb
@@ -0,0 +1,67 @@
+module Groonga
+  module ExpressionTree
+    class BinaryOperation
+      attr_reader :operator
+      attr_reader :left
+      attr_reader :right
+      def initialize(operator, left, right)
+        @operator = operator
+        @left = left
+        @right = right
+      end
+
+      def build(expression)
+        @left.build(expression)
+        @right.build(expression)
+        expression.append_operator(@operator, 2)
+      end
+
+      RANGE_OPERATORS = [
+        Operator::LESS,
+        Operator::GREATER,
+        Operator::LESS_EQUAL,
+        Operator::GREATER_EQUAL,
+      ]
+      def estimate_size(table)
+        case @operator
+        when *RANGE_OPERATORS
+          estimate_size_range(table)
+        else
+          table.size
+        end
+      end
+
+      private
+      def estimate_size_range(table)
+        return table.size unless @left.is_a?(Variable)
+        return table.size unless @right.is_a?(Constant)
+
+        column = @left.column
+        value = @right.value
+        index_info = column.find_index(@operator)
+        return table.size if index_info.nil?
+
+        index_column = index_info.index
+        lexicon = index_column.lexicon
+        options = {}
+        case @operator
+        when Operator::LESS
+          options[:max] = value
+          options[:flags] = TableCursorFlags::LT
+        when Operator::LESS_EQUAL
+          options[:max] = value
+          options[:flags] = TableCursorFlags::LE
+        when Operator::GREATER
+          options[:min] = value
+          options[:flags] = TableCursorFlags::GT
+        when Operator::GREATER_EQUAL
+          options[:min] = value
+          options[:flags] = TableCursorFlags::GE
+        end
+        TableCursor.open(lexicon, options) do |cursor|
+          index_column.estimate_size(:lexicon_cursor => cursor)
+        end
+      end
+    end
+  end
+end