# Copyright 2015 The TensorFlow Authors. All Rights Reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
# ==============================================================================
"""Tests for Reader ops from io_ops."""

from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import collections
import gzip
import os
import threading
import zlib

import six

from tensorflow.core.protobuf import config_pb2
from tensorflow.python.framework import dtypes
from tensorflow.python.framework import errors_impl
from tensorflow.python.lib.io import tf_record
from tensorflow.python.ops import data_flow_ops
from tensorflow.python.ops import io_ops
from tensorflow.python.ops import variables
from tensorflow.python.platform import test
from tensorflow.python.util import compat

# pylint: disable=invalid-name
TFRecordCompressionType = tf_record.TFRecordCompressionType
# pylint: enable=invalid-name

# Edgar Allan Poe's 'Eldorado'
_TEXT = b"""Gaily bedight,
    A gallant knight,
    In sunshine and in shadow,
    Had journeyed long,
    Singing a song,
    In search of Eldorado.

    But he grew old
    This knight so bold
    And o'er his heart a shadow
    Fell as he found
    No spot of ground
    That looked like Eldorado.

   And, as his strength
   Failed him at length,
   He met a pilgrim shadow
   'Shadow,' said he,
   'Where can it be
   This land of Eldorado?'

   'Over the Mountains
    Of the Moon'
    Down the Valley of the Shadow,
    Ride, boldly ride,'
    The shade replied,
    'If you seek for Eldorado!'
    """


class IdentityReaderTest(test.TestCase):

  def _ExpectRead(self, sess, key, value, expected):
    k, v = sess.run([key, value])
    self.assertAllEqual(expected, k)
    self.assertAllEqual(expected, v)

  def testOneEpoch(self):
    with self.test_session() as sess:
      reader = io_ops.IdentityReader("test_reader")
      work_completed = reader.num_work_units_completed()
      produced = reader.num_records_produced()
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      queued_length = queue.size()
      key, value = reader.read(queue)

      self.assertAllEqual(0, work_completed.eval())
      self.assertAllEqual(0, produced.eval())
      self.assertAllEqual(0, queued_length.eval())

      queue.enqueue_many([["A", "B", "C"]]).run()
      queue.close().run()
      self.assertAllEqual(3, queued_length.eval())

      self._ExpectRead(sess, key, value, b"A")
      self.assertAllEqual(1, produced.eval())

      self._ExpectRead(sess, key, value, b"B")

      self._ExpectRead(sess, key, value, b"C")
      self.assertAllEqual(3, produced.eval())
      self.assertAllEqual(0, queued_length.eval())

      with self.assertRaisesOpError("is closed and has insufficient elements "
                                    "\\(requested 1, current size 0\\)"):
        sess.run([key, value])

      self.assertAllEqual(3, work_completed.eval())
      self.assertAllEqual(3, produced.eval())
      self.assertAllEqual(0, queued_length.eval())

  def testMultipleEpochs(self):
    with self.test_session() as sess:
      reader = io_ops.IdentityReader("test_reader")
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      enqueue = queue.enqueue_many([["DD", "EE"]])
      key, value = reader.read(queue)

      enqueue.run()
      self._ExpectRead(sess, key, value, b"DD")
      self._ExpectRead(sess, key, value, b"EE")
      enqueue.run()
      self._ExpectRead(sess, key, value, b"DD")
      self._ExpectRead(sess, key, value, b"EE")
      enqueue.run()
      self._ExpectRead(sess, key, value, b"DD")
      self._ExpectRead(sess, key, value, b"EE")
      queue.close().run()
      with self.assertRaisesOpError("is closed and has insufficient elements "
                                    "\\(requested 1, current size 0\\)"):
        sess.run([key, value])

  def testSerializeRestore(self):
    with self.test_session() as sess:
      reader = io_ops.IdentityReader("test_reader")
      produced = reader.num_records_produced()
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      queue.enqueue_many([["X", "Y", "Z"]]).run()
      key, value = reader.read(queue)

      self._ExpectRead(sess, key, value, b"X")
      self.assertAllEqual(1, produced.eval())
      state = reader.serialize_state().eval()

      self._ExpectRead(sess, key, value, b"Y")
      self._ExpectRead(sess, key, value, b"Z")
      self.assertAllEqual(3, produced.eval())

      queue.enqueue_many([["Y", "Z"]]).run()
      queue.close().run()
      reader.restore_state(state).run()
      self.assertAllEqual(1, produced.eval())
      self._ExpectRead(sess, key, value, b"Y")
      self._ExpectRead(sess, key, value, b"Z")
      with self.assertRaisesOpError("is closed and has insufficient elements "
                                    "\\(requested 1, current size 0\\)"):
        sess.run([key, value])
      self.assertAllEqual(3, produced.eval())

      self.assertEqual(bytes, type(state))

      with self.assertRaises(ValueError):
        reader.restore_state([])

      with self.assertRaises(ValueError):
        reader.restore_state([state, state])

      with self.assertRaisesOpError(
          "Could not parse state for IdentityReader 'test_reader'"):
        reader.restore_state(state[1:]).run()

      with self.assertRaisesOpError(
          "Could not parse state for IdentityReader 'test_reader'"):
        reader.restore_state(state[:-1]).run()

      with self.assertRaisesOpError(
          "Could not parse state for IdentityReader 'test_reader'"):
        reader.restore_state(state + b"ExtraJunk").run()

      with self.assertRaisesOpError(
          "Could not parse state for IdentityReader 'test_reader'"):
        reader.restore_state(b"PREFIX" + state).run()

      with self.assertRaisesOpError(
          "Could not parse state for IdentityReader 'test_reader'"):
        reader.restore_state(b"BOGUS" + state[5:]).run()

  def testReset(self):
    with self.test_session() as sess:
      reader = io_ops.IdentityReader("test_reader")
      work_completed = reader.num_work_units_completed()
      produced = reader.num_records_produced()
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      queued_length = queue.size()
      key, value = reader.read(queue)

      queue.enqueue_many([["X", "Y", "Z"]]).run()
      self._ExpectRead(sess, key, value, b"X")
      self.assertLess(0, queued_length.eval())
      self.assertAllEqual(1, produced.eval())

      self._ExpectRead(sess, key, value, b"Y")
      self.assertLess(0, work_completed.eval())
      self.assertAllEqual(2, produced.eval())

      reader.reset().run()
      self.assertAllEqual(0, work_completed.eval())
      self.assertAllEqual(0, produced.eval())
      self.assertAllEqual(1, queued_length.eval())
      self._ExpectRead(sess, key, value, b"Z")

      queue.enqueue_many([["K", "L"]]).run()
      self._ExpectRead(sess, key, value, b"K")


class WholeFileReaderTest(test.TestCase):

  def setUp(self):
    super(WholeFileReaderTest, self).setUp()
    self._filenames = [
        os.path.join(self.get_temp_dir(), "whole_file.%d.txt" % i)
        for i in range(3)
    ]
    self._content = [b"One\na\nb\n", b"Two\nC\nD", b"Three x, y, z"]
    for fn, c in zip(self._filenames, self._content):
      with open(fn, "wb") as h:
        h.write(c)

  def tearDown(self):
    for fn in self._filenames:
      os.remove(fn)
    super(WholeFileReaderTest, self).tearDown()

  def _ExpectRead(self, sess, key, value, index):
    k, v = sess.run([key, value])
    self.assertAllEqual(compat.as_bytes(self._filenames[index]), k)
    self.assertAllEqual(self._content[index], v)

  def testOneEpoch(self):
    with self.test_session() as sess:
      reader = io_ops.WholeFileReader("test_reader")
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      queue.enqueue_many([self._filenames]).run()
      queue.close().run()
      key, value = reader.read(queue)

      self._ExpectRead(sess, key, value, 0)
      self._ExpectRead(sess, key, value, 1)
      self._ExpectRead(sess, key, value, 2)

      with self.assertRaisesOpError("is closed and has insufficient elements "
                                    "\\(requested 1, current size 0\\)"):
        sess.run([key, value])

  def testInfiniteEpochs(self):
    with self.test_session() as sess:
      reader = io_ops.WholeFileReader("test_reader")
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      enqueue = queue.enqueue_many([self._filenames])
      key, value = reader.read(queue)

      enqueue.run()
      self._ExpectRead(sess, key, value, 0)
      self._ExpectRead(sess, key, value, 1)
      enqueue.run()
      self._ExpectRead(sess, key, value, 2)
      self._ExpectRead(sess, key, value, 0)
      self._ExpectRead(sess, key, value, 1)
      enqueue.run()
      self._ExpectRead(sess, key, value, 2)
      self._ExpectRead(sess, key, value, 0)


class TextLineReaderTest(test.TestCase):

  def setUp(self):
    super(TextLineReaderTest, self).setUp()
    self._num_files = 2
    self._num_lines = 5

  def _LineText(self, f, l):
    return compat.as_bytes("%d: %d" % (f, l))

  def _CreateFiles(self, crlf=False):
    filenames = []
    for i in range(self._num_files):
      fn = os.path.join(self.get_temp_dir(), "text_line.%d.txt" % i)
      filenames.append(fn)
      with open(fn, "wb") as f:
        for j in range(self._num_lines):
          f.write(self._LineText(i, j))
          # Always include a newline after the record unless it is
          # at the end of the file, in which case we include it sometimes.
          if j + 1 != self._num_lines or i == 0:
            f.write(b"\r\n" if crlf else b"\n")
    return filenames

  def _testOneEpoch(self, files):
    with self.test_session() as sess:
      reader = io_ops.TextLineReader(name="test_reader")
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      key, value = reader.read(queue)

      queue.enqueue_many([files]).run()
      queue.close().run()
      for i in range(self._num_files):
        for j in range(self._num_lines):
          k, v = sess.run([key, value])
          self.assertAllEqual("%s:%d" % (files[i], j + 1), compat.as_text(k))
          self.assertAllEqual(self._LineText(i, j), v)

      with self.assertRaisesOpError("is closed and has insufficient elements "
                                    "\\(requested 1, current size 0\\)"):
        k, v = sess.run([key, value])

  def testOneEpochLF(self):
    self._testOneEpoch(self._CreateFiles(crlf=False))

  def testOneEpochCRLF(self):
    self._testOneEpoch(self._CreateFiles(crlf=True))

  def testSkipHeaderLines(self):
    files = self._CreateFiles()
    with self.test_session() as sess:
      reader = io_ops.TextLineReader(skip_header_lines=1, name="test_reader")
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      key, value = reader.read(queue)

      queue.enqueue_many([files]).run()
      queue.close().run()
      for i in range(self._num_files):
        for j in range(self._num_lines - 1):
          k, v = sess.run([key, value])
          self.assertAllEqual("%s:%d" % (files[i], j + 2), compat.as_text(k))
          self.assertAllEqual(self._LineText(i, j + 1), v)

      with self.assertRaisesOpError("is closed and has insufficient elements "
                                    "\\(requested 1, current size 0\\)"):
        k, v = sess.run([key, value])


class FixedLengthRecordReaderTest(test.TestCase):

  def setUp(self):
    super(FixedLengthRecordReaderTest, self).setUp()
    self._num_files = 2
    self._num_records = 7
    self._header_bytes = 5
    self._record_bytes = 3
    self._footer_bytes = 2

  def _Record(self, f, r):
    return compat.as_bytes(str(f * 2 + r) * self._record_bytes)

  def _CreateFiles(self):
    filenames = []
    for i in range(self._num_files):
      fn = os.path.join(self.get_temp_dir(), "fixed_length_record.%d.txt" % i)
      filenames.append(fn)
      with open(fn, "wb") as f:
        f.write(b"H" * self._header_bytes)
        for j in range(self._num_records):
          f.write(self._Record(i, j))
        f.write(b"F" * self._footer_bytes)
    return filenames

  def testOneEpoch(self):
    files = self._CreateFiles()
    with self.test_session() as sess:
      reader = io_ops.FixedLengthRecordReader(
          header_bytes=self._header_bytes,
          record_bytes=self._record_bytes,
          footer_bytes=self._footer_bytes,
          name="test_reader")
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      key, value = reader.read(queue)

      queue.enqueue_many([files]).run()
      queue.close().run()
      for i in range(self._num_files):
        for j in range(self._num_records):
          k, v = sess.run([key, value])
          self.assertAllEqual("%s:%d" % (files[i], j), compat.as_text(k))
          self.assertAllEqual(self._Record(i, j), v)

      with self.assertRaisesOpError("is closed and has insufficient elements "
                                    "\\(requested 1, current size 0\\)"):
        k, v = sess.run([key, value])


class TFRecordReaderTest(test.TestCase):

  def setUp(self):
    super(TFRecordReaderTest, self).setUp()
    self._num_files = 2
    self._num_records = 7

  def _Record(self, f, r):
    return compat.as_bytes("Record %d of file %d" % (r, f))

  def _CreateFiles(self):
    filenames = []
    for i in range(self._num_files):
      fn = os.path.join(self.get_temp_dir(), "tf_record.%d.txt" % i)
      filenames.append(fn)
      writer = tf_record.TFRecordWriter(fn)
      for j in range(self._num_records):
        writer.write(self._Record(i, j))
    return filenames

  def testOneEpoch(self):
    files = self._CreateFiles()
    with self.test_session() as sess:
      reader = io_ops.TFRecordReader(name="test_reader")
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      key, value = reader.read(queue)

      queue.enqueue_many([files]).run()
      queue.close().run()
      for i in range(self._num_files):
        for j in range(self._num_records):
          k, v = sess.run([key, value])
          self.assertTrue(compat.as_text(k).startswith("%s:" % files[i]))
          self.assertAllEqual(self._Record(i, j), v)

      with self.assertRaisesOpError("is closed and has insufficient elements "
                                    "\\(requested 1, current size 0\\)"):
        k, v = sess.run([key, value])

  def testReadUpTo(self):
    files = self._CreateFiles()
    with self.test_session() as sess:
      reader = io_ops.TFRecordReader(name="test_reader")
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      batch_size = 3
      key, value = reader.read_up_to(queue, batch_size)

      queue.enqueue_many([files]).run()
      queue.close().run()
      num_k = 0
      num_v = 0

      while True:
        try:
          k, v = sess.run([key, value])
          # Test reading *up to* batch_size records
          self.assertLessEqual(len(k), batch_size)
          self.assertLessEqual(len(v), batch_size)
          num_k += len(k)
          num_v += len(v)
        except errors_impl.OutOfRangeError:
          break

      # Test that we have read everything
      self.assertEqual(self._num_files * self._num_records, num_k)
      self.assertEqual(self._num_files * self._num_records, num_v)

  def testReadZlibFiles(self):
    files = self._CreateFiles()
    zlib_files = []
    for i, fn in enumerate(files):
      with open(fn, "rb") as f:
        cdata = zlib.compress(f.read())

        zfn = os.path.join(self.get_temp_dir(), "tfrecord_%s.z" % i)
        with open(zfn, "wb") as f:
          f.write(cdata)
        zlib_files.append(zfn)

    with self.test_session() as sess:
      options = tf_record.TFRecordOptions(TFRecordCompressionType.ZLIB)
      reader = io_ops.TFRecordReader(name="test_reader", options=options)
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      key, value = reader.read(queue)

      queue.enqueue_many([zlib_files]).run()
      queue.close().run()
      for i in range(self._num_files):
        for j in range(self._num_records):
          k, v = sess.run([key, value])
          self.assertTrue(compat.as_text(k).startswith("%s:" % zlib_files[i]))
          self.assertAllEqual(self._Record(i, j), v)

  def testReadGzipFiles(self):
    files = self._CreateFiles()
    gzip_files = []
    for i, fn in enumerate(files):
      with open(fn, "rb") as f:
        cdata = f.read()

        zfn = os.path.join(self.get_temp_dir(), "tfrecord_%s.gz" % i)
        with gzip.GzipFile(zfn, "wb") as f:
          f.write(cdata)
        gzip_files.append(zfn)

    with self.test_session() as sess:
      options = tf_record.TFRecordOptions(TFRecordCompressionType.GZIP)
      reader = io_ops.TFRecordReader(name="test_reader", options=options)
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      key, value = reader.read(queue)

      queue.enqueue_many([gzip_files]).run()
      queue.close().run()
      for i in range(self._num_files):
        for j in range(self._num_records):
          k, v = sess.run([key, value])
          self.assertTrue(compat.as_text(k).startswith("%s:" % gzip_files[i]))
          self.assertAllEqual(self._Record(i, j), v)


class TFRecordWriterZlibTest(test.TestCase):

  def setUp(self):
    super(TFRecordWriterZlibTest, self).setUp()
    self._num_files = 2
    self._num_records = 7

  def _Record(self, f, r):
    return compat.as_bytes("Record %d of file %d" % (r, f))

  def _CreateFiles(self):
    filenames = []
    for i in range(self._num_files):
      fn = os.path.join(self.get_temp_dir(), "tf_record.%d.txt" % i)
      filenames.append(fn)
      options = tf_record.TFRecordOptions(
          compression_type=TFRecordCompressionType.ZLIB)
      writer = tf_record.TFRecordWriter(fn, options=options)
      for j in range(self._num_records):
        writer.write(self._Record(i, j))
      writer.close()
      del writer

    return filenames

  def _WriteRecordsToFile(self, records, name="tf_record"):
    fn = os.path.join(self.get_temp_dir(), name)
    writer = tf_record.TFRecordWriter(fn, options=None)
    for r in records:
      writer.write(r)
    writer.close()
    del writer
    return fn

  def _ZlibCompressFile(self, infile, name="tfrecord.z"):
    # zlib compress the file and write compressed contents to file.
    with open(infile, "rb") as f:
      cdata = zlib.compress(f.read())

    zfn = os.path.join(self.get_temp_dir(), name)
    with open(zfn, "wb") as f:
      f.write(cdata)
    return zfn

  def testOneEpoch(self):
    files = self._CreateFiles()
    with self.test_session() as sess:
      options = tf_record.TFRecordOptions(
          compression_type=TFRecordCompressionType.ZLIB)
      reader = io_ops.TFRecordReader(name="test_reader", options=options)
      queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
      key, value = reader.read(queue)

      queue.enqueue_many([files]).run()
      queue.close().run()
      for i in range(self._num_files):
        for j in range(self._num_records):
          k, v = sess.run([key, value])
          self.assertTrue(compat.as_text(k).startswith("%s:" % files[i]))
          self.assertAllEqual(self._Record(i, j), v)

      with self.assertRaisesOpError("is closed and has insufficient elements "
                                    "\\(requested 1, current size 0\\)"):
        k, v = sess.run([key, value])

  def testZLibFlushRecord(self):
    fn = self._WriteRecordsToFile([b"small record"], "small_record")
    with open(fn, "rb") as h:
      buff = h.read()

    # creating more blocks and trailing blocks shouldn't break reads
    compressor = zlib.compressobj(9, zlib.DEFLATED, zlib.MAX_WBITS)

    output = b""
    for c in buff:
      if isinstance(c, int):
        c = six.int2byte(c)
      output += compressor.compress(c)
      output += compressor.flush(zlib.Z_FULL_FLUSH)

    output += compressor.flush(zlib.Z_FULL_FLUSH)
    output += compressor.flush(zlib.Z_FULL_FLUSH)
    output += compressor.flush(zlib.Z_FINISH)

    # overwrite the original file with the compressed data
    with open(fn, "wb") as h:
      h.write(output)

    with self.test_session() as sess:
      options = tf_record.TFRecordOptions(
          compression_type=TFRecordCompressionType.ZLIB)
      reader = io_ops.TFRecordReader(name="test_reader", options=options)
      queue = data_flow_ops.FIFOQueue(1, [dtypes.string], shapes=())
      key, value = reader.read(queue)
      queue.enqueue(fn).run()
      queue.close().run()
      k, v = sess.run([key, value])
      self.assertTrue(compat.as_text(k).startswith("%s:" % fn))
      self.assertAllEqual(b"small record", v)

  def testZlibReadWrite(self):
    """Verify that files produced are zlib compatible."""
    original = [b"foo", b"bar"]
    fn = self._WriteRecordsToFile(original, "zlib_read_write.tfrecord")
    zfn = self._ZlibCompressFile(fn, "zlib_read_write.tfrecord.z")

    # read the compressed contents and verify.
    actual = []
    for r in tf_record.tf_record_iterator(
        zfn,
        options=tf_record.TFRecordOptions(
            tf_record.TFRecordCompressionType.ZLIB)):
      actual.append(r)
    self.assertEqual(actual, original)

  def testZlibReadWriteLarge(self):
    """Verify that writing large contents also works."""

    # Make it large (about 5MB)
    original = [_TEXT * 10240]
    fn = self._WriteRecordsToFile(original, "zlib_read_write_large.tfrecord")
    zfn = self._ZlibCompressFile(fn, "zlib_read_write_large.tfrecord.z")

    # read the compressed contents and verify.
    actual = []
    for r in tf_record.tf_record_iterator(
        zfn,
        options=tf_record.TFRecordOptions(
            tf_record.TFRecordCompressionType.ZLIB)):
      actual.append(r)
    self.assertEqual(actual, original)

  def testGzipReadWrite(self):
    """Verify that files produced are gzip compatible."""
    original = [b"foo", b"bar"]
    fn = self._WriteRecordsToFile(original, "gzip_read_write.tfrecord")

    # gzip compress the file and write compressed contents to file.
    with open(fn, "rb") as f:
      cdata = f.read()
    gzfn = os.path.join(self.get_temp_dir(), "tf_record.gz")
    with gzip.GzipFile(gzfn, "wb") as f:
      f.write(cdata)

    actual = []
    for r in tf_record.tf_record_iterator(
        gzfn, options=tf_record.TFRecordOptions(TFRecordCompressionType.GZIP)):
      actual.append(r)
    self.assertEqual(actual, original)


class TFRecordIteratorTest(test.TestCase):

  def setUp(self):
    super(TFRecordIteratorTest, self).setUp()
    self._num_records = 7

  def _Record(self, r):
    return compat.as_bytes("Record %d" % r)

  def _WriteCompressedRecordsToFile(
      self,
      records,
      name="tfrecord.z",
      compression_type=tf_record.TFRecordCompressionType.ZLIB):
    fn = os.path.join(self.get_temp_dir(), name)
    options = tf_record.TFRecordOptions(compression_type=compression_type)
    writer = tf_record.TFRecordWriter(fn, options=options)
    for r in records:
      writer.write(r)
    writer.close()
    del writer
    return fn

  def _ZlibDecompressFile(self, infile, name="tfrecord", wbits=zlib.MAX_WBITS):
    with open(infile, "rb") as f:
      cdata = zlib.decompress(f.read(), wbits)
    zfn = os.path.join(self.get_temp_dir(), name)
    with open(zfn, "wb") as f:
      f.write(cdata)
    return zfn

  def testIterator(self):
    fn = self._WriteCompressedRecordsToFile(
        [self._Record(i) for i in range(self._num_records)],
        "compressed_records")
    options = tf_record.TFRecordOptions(
        compression_type=TFRecordCompressionType.ZLIB)
    reader = tf_record.tf_record_iterator(fn, options)
    for i in range(self._num_records):
      record = next(reader)
      self.assertAllEqual(self._Record(i), record)
    with self.assertRaises(StopIteration):
      record = next(reader)

  def testWriteZlibRead(self):
    """Verify compression with TFRecordWriter is zlib library compatible."""
    original = [b"foo", b"bar"]
    fn = self._WriteCompressedRecordsToFile(original,
                                            "write_zlib_read.tfrecord.z")
    zfn = self._ZlibDecompressFile(fn, "write_zlib_read.tfrecord")
    actual = []
    for r in tf_record.tf_record_iterator(zfn):
      actual.append(r)
    self.assertEqual(actual, original)

  def testWriteZlibReadLarge(self):
    """Verify compression for large records is zlib library compatible."""
    # Make it large (about 5MB)
    original = [_TEXT * 10240]
    fn = self._WriteCompressedRecordsToFile(original,
                                            "write_zlib_read_large.tfrecord.z")
    zfn = self._ZlibDecompressFile(fn, "write_zlib_read_large.tf_record")
    actual = []
    for r in tf_record.tf_record_iterator(zfn):
      actual.append(r)
    self.assertEqual(actual, original)

  def testWriteGzipRead(self):
    original = [b"foo", b"bar"]
    fn = self._WriteCompressedRecordsToFile(
        original,
        "write_gzip_read.tfrecord.gz",
        compression_type=TFRecordCompressionType.GZIP)

    with gzip.GzipFile(fn, "rb") as f:
      cdata = f.read()
    zfn = os.path.join(self.get_temp_dir(), "tf_record")
    with open(zfn, "wb") as f:
      f.write(cdata)

    actual = []
    for r in tf_record.tf_record_iterator(zfn):
      actual.append(r)
    self.assertEqual(actual, original)

  def testBadFile(self):
    """Verify that tf_record_iterator throws an exception on bad TFRecords."""
    fn = os.path.join(self.get_temp_dir(), "bad_file")
    with tf_record.TFRecordWriter(fn) as writer:
      writer.write(b"123")
    fn_truncated = os.path.join(self.get_temp_dir(), "bad_file_truncated")
    with open(fn, "rb") as f:
      with open(fn_truncated, "wb") as f2:
        # DataLossError requires that we've written the header, so this must
        # be at least 12 bytes.
        f2.write(f.read(14))
    with self.assertRaises(errors_impl.DataLossError):
      for _ in tf_record.tf_record_iterator(fn_truncated):
        pass


class AsyncReaderTest(test.TestCase):

  def testNoDeadlockFromQueue(self):
    """Tests that reading does not block main execution threads."""
    config = config_pb2.ConfigProto(
        inter_op_parallelism_threads=1, intra_op_parallelism_threads=1)
    with self.test_session(config=config) as sess:
      thread_data_t = collections.namedtuple("thread_data_t",
                                             ["thread", "queue", "output"])
      thread_data = []

      # Create different readers, each with its own queue.
      for i in range(3):
        queue = data_flow_ops.FIFOQueue(99, [dtypes.string], shapes=())
        reader = io_ops.TextLineReader()
        _, line = reader.read(queue)
        output = []
        t = threading.Thread(
            target=AsyncReaderTest._RunSessionAndSave,
            args=(sess, [line], output))
        thread_data.append(thread_data_t(t, queue, output))

      # Start all readers. They are all blocked waiting for queue entries.
      sess.run(variables.global_variables_initializer())
      for d in thread_data:
        d.thread.start()

      # Unblock the readers.
      for i, d in enumerate(reversed(thread_data)):
        fname = os.path.join(self.get_temp_dir(), "deadlock.%s.txt" % i)
        with open(fname, "wb") as f:
          f.write(("file-%s" % i).encode())
        d.queue.enqueue_many([[fname]]).run()
        d.thread.join()
        self.assertEqual([[("file-%s" % i).encode()]], d.output)

  @staticmethod
  def _RunSessionAndSave(sess, args, output):
    output.append(sess.run(args))


if __name__ == "__main__":
  test.main()
