add readline to GridOut PYTHON-157

Author: Mike Dirolf

gridfs/grid_file.py

@@ -390,6 +390,22 @@ def read(self, size=-1):
  self.__buffer = data[size:]
  return to_return
 
+ def readline(self, size=-1):
+ """Read one line or up to `size` bytes from the file.
+
+ :Parameters:
+ - `size` (optional): the maximum number of bytes to read
+
+ .. versionadded:: 1.8.1+
+ """
+ bytes = ""
+ while len(bytes) != size:
+ byte = self.read(1)
+ bytes += byte
+ if byte == "" or byte =="\n":
+ break
+ return bytes
+
  def tell(self):
  """Return the current position of this file.
  """

test/test_grid_file.py

@@ -367,6 +367,24 @@ def test_multiple_reads(self):
  self.assertEqual("d", g.read(2))
  self.assertEqual("", g.read(2))
 
+ def test_readline(self):
+ f = GridIn(self.db.fs, chunkSize=5)
+ f.write("""Hello world,
+How are you?
+Hope all is well.
+Bye""")
+ f.close()
+
+ g = GridOut(self.db.fs, f._id)
+ self.assertEqual("H", g.read(1))
+ self.assertEqual("ello world,\n", g.readline())
+ self.assertEqual("How a", g.readline(5))
+ self.assertEqual("", g.readline(0))
+ self.assertEqual("re you?\n", g.readline())
+ self.assertEqual("Hope all is well.\n", g.readline(1000))
+ self.assertEqual("Bye", g.readline())
+ self.assertEqual("", g.readline())
+
  def test_iterator(self):
  f = GridIn(self.db.fs)
  f.close()