Don't use enumerator in CSV (#363)

GitHub: Fix GH-361

CSV::Parser#parse can continue from the previous state.

Reported by Cas Donoghue. Thanks!!!

Author: kou

lib/csv.rb

@@ -2110,8 +2110,6 @@ def initialize(data,
       strip: strip,
     }
     @parser = nil
-    @parser_enumerator = nil
-    @eof_error = nil
 
     @writer_options = {
       encoding: @encoding,
@@ -2430,24 +2428,13 @@ def to_io
   end
 
   def eof?
-    return false if @eof_error
-    begin
-      parser_enumerator.peek
-      false
-    rescue MalformedCSVError => error
-      @eof_error = error
-      false
-    rescue StopIteration
-      true
-    end
+    parser.eof?
   end
   alias_method :eof, :eof?
 
   # Rewinds the underlying IO object and resets CSV's lineno() counter.
   def rewind
     @parser = nil
-    @parser_enumerator = nil
-    @eof_error = nil
     @writer.rewind if @writer
     @io.rewind
   end
@@ -2687,13 +2674,7 @@ def header_convert(name = nil, &converter)
   #     p row
   #   end
   def each(&block)
-    return to_enum(__method__) unless block_given?
-    begin
-      while true
-        yield(parser_enumerator.next)
-      end
-    rescue StopIteration
-    end
+    parser.parse(&block)
   end
 
   # :call-seq:
@@ -2801,15 +2782,10 @@ def header_row?
   #   # Raises IOError (not opened for reading)
   #   csv.shift
   def shift
-    if @eof_error
-      eof_error, @eof_error = @eof_error, nil
-      raise eof_error
-    end
-    begin
-      parser_enumerator.next
-    rescue StopIteration
-      nil
+    parser.parse do |row|
+      return row
     end
+    nil
   end
   alias_method :gets,     :shift
   alias_method :readline, :shift
@@ -2971,10 +2947,6 @@ def parser_options
                           fields_converter: parser_fields_converter)
   end
 
-  def parser_enumerator
-    @parser_enumerator ||= parser.parse
-  end
-
   def writer
     @writer ||= Writer.new(@io, writer_options)
   end

lib/csv/parser.rb

@@ -181,7 +181,7 @@ def scan_all(pattern)
       end
 
       def eos?
-        @scanner.eos?
+        @last_scanner and @scanner.eos?
       end
 
       def keep_start
@@ -444,6 +444,11 @@ def parse(&block)
       end
     end
 
+    def eof?
+      return false if @scanner.nil?
+      @scanner.eos?
+    end
+
     def use_headers?
       @use_headers
     end