class Sequel::Dataset::PlaceholderLiteralizer::Recorder
Records the offsets at which the placeholder arguments are used in the SQL query.
Public Instance Methods
Return an Argument with the specified position, or the next position. In general you shouldn't mix calls with an argument and calls without an argument for the same receiver.
# File lib/sequel/dataset/placeholder_literalizer.rb, line 87 def arg(v=(no_arg_given = true; @argn+=1)) unless no_arg_given @argn = v if @argn < v end Argument.new(self, v) end
Yields the receiver and the dataset to the block, which should call arg on the receiver for each placeholder argument, and return the dataset that you want to load.
# File lib/sequel/dataset/placeholder_literalizer.rb, line 80 def loader(dataset, &block) PlaceholderLiteralizer.new(*process(dataset, &block)) end
Record the offset at which the argument is used in the SQL query, and any transforming block.
# File lib/sequel/dataset/placeholder_literalizer.rb, line 96 def use(sql, arg, transformer) @args << [sql, sql.length, arg, transformer] end
Private Instance Methods
Return an array with two elements, the first being an SQL string with interpolated prepared argument placeholders (suitable for inspect), the the second being an array of SQL fragments suitable for using for creating a Sequel::SQL::PlaceholderLiteralString. Designed for use with emulated prepared statements.
# File lib/sequel/dataset/placeholder_literalizer.rb, line 108 def prepared_sql_and_frags(dataset, prepared_args, &block) _, frags, final_sql, _ = process(dataset, &block) frags = frags.map(&:first) prepared_sql = String.new frags.each_with_index do |sql, i| prepared_sql << sql prepared_sql << "$#{prepared_args[i]}" end if final_sql frags << final_sql prepared_sql << final_sql end [prepared_sql, frags] end
Internals of loader and prepared_sql_and_frags.
# File lib/sequel/dataset/placeholder_literalizer.rb, line 126 def process(dataset) @argn = -1 @args = [] ds = yield self, dataset sql = ds.clone(:placeholder_literalizer=>self).sql last_offset = 0 fragments = @args.map do |used_sql, offset, arg, t| raise Error, "placeholder literalizer argument literalized into different string than dataset returned" unless used_sql.equal?(sql) a = [sql[last_offset...offset], arg, t] last_offset = offset a end final_sql = sql[last_offset..-1] arity = @argn+1 [ds, fragments, final_sql, arity] end