1# Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5
6from autotest_lib.client.cros.video import method_logger
7
8
9class ScreenShotFileNamer(object):
10    """
11    Creates a filename of an image given instance in time it was captured.
12
13    Encapsulates the mapping from a timestamp to a filename.
14
15    There are two uses of this class.
16
17    When downloading golden images, we will have timestamps that we will want
18    the images for. Using this class, we will neatly get the filenames from the
19    timestamps.
20
21    When capturing test screenshots we will have timestamps also. Again using
22    this class we can SAVE the images in the appropriate names. This ensures
23    the golden image and test image that are from the same timestamp have
24    exactly the same name.
25
26    """
27
28
29    @method_logger.log
30    def __init__(self, image_format):
31        self._image_format = image_format
32
33
34    @property
35    def image_format(self):
36        """
37        Returns the format to use for the image.
38
39        """
40        return self._image_format
41
42
43    @method_logger.log
44    def get_filename(self, time_delta_value):
45        """
46        Gets required full filename for a screenshot image.
47
48        @param time_delta_value: time_delta, the time value at which
49        an image will be or has been captured.
50
51        @returns filename encoded based on the time value, as a string.
52
53        """
54        hours, remainder = divmod(time_delta_value.total_seconds(), 3600)
55
56        minutes, seconds = divmod(remainder, 60)
57
58        # integer division, discard decimal milliseconds
59        milliseconds = time_delta_value.microseconds // 1000
60
61        filename = "%02d_%02d_%02d_%03d" % (
62            hours, minutes, seconds, milliseconds)
63
64        return filename + '.' + self.image_format
65