Pillow/Tests/test_file_png.py
Jon Dufresne 4cd4adddc3 Improve handling of file resources
Follow Python's file object semantics. User code is responsible for
closing resources (usually through a context manager) in a deterministic
way.

To achieve this, remove __del__ functions. These functions used to
closed open file handlers in an attempt to silence Python
ResourceWarnings. However, using __del__ has the following drawbacks:

- __del__ isn't called until the object's reference count reaches 0.
  Therefore, resource handlers remain open or in use longer than
  necessary.

- The __del__ method isn't guaranteed to execute on system exit. See the
  Python documentation:

  https://docs.python.org/3/reference/datamodel.html#object.__del__

  > It is not guaranteed that __del__() methods are called for objects
  > that still exist when the interpreter exits.

- Exceptions that occur inside __del__ are ignored instead of raised.
  This has the potential of hiding bugs. This is also in the Python
  documentation:

  > Warning: Due to the precarious circumstances under which __del__()
  > methods are invoked, exceptions that occur during their execution
  > are ignored, and a warning is printed to sys.stderr instead.

Instead, always close resource handlers when they are no longer in use.
This will close the file handler at a specified point in the user's code
and not wait until the interpreter chooses to. It is always guaranteed
to run. And, if an exception occurs while closing the file handler, the
bug will not be ignored.

Now, when code receives a ResourceWarning, it will highlight an area
that is mishandling resources. It should not simply be silenced, but
fixed by closing resources with a context manager.

All warnings that were emitted during tests have been cleaned up. To
enable warnings, I passed the `-Wa` CLI option to Python. This exposed
some mishandling of resources in ImageFile.__init__() and
SpiderImagePlugin.loadImageSeries(), they too were fixed.
2019-10-12 08:27:17 -07:00

682 lines
22 KiB
Python

import zlib
from io import BytesIO
from PIL import Image, ImageFile, PngImagePlugin
from PIL._util import py3
from .helper import PillowLeakTestCase, PillowTestCase, hopper, is_win32, unittest
try:
from PIL import _webp
HAVE_WEBP = True
except ImportError:
HAVE_WEBP = False
codecs = dir(Image.core)
# sample png stream
TEST_PNG_FILE = "Tests/images/hopper.png"
# stuff to create inline PNG images
MAGIC = PngImagePlugin._MAGIC
def chunk(cid, *data):
test_file = BytesIO()
PngImagePlugin.putchunk(*(test_file, cid) + data)
return test_file.getvalue()
o32 = PngImagePlugin.o32
IHDR = chunk(b"IHDR", o32(1), o32(1), b"\x08\x02", b"\0\0\0")
IDAT = chunk(b"IDAT")
IEND = chunk(b"IEND")
HEAD = MAGIC + IHDR
TAIL = IDAT + IEND
def load(data):
return Image.open(BytesIO(data))
def roundtrip(im, **options):
out = BytesIO()
im.save(out, "PNG", **options)
out.seek(0)
return Image.open(out)
class TestFilePng(PillowTestCase):
def setUp(self):
if "zip_encoder" not in codecs or "zip_decoder" not in codecs:
self.skipTest("zip/deflate support not available")
def get_chunks(self, filename):
chunks = []
with open(filename, "rb") as fp:
fp.read(8)
with PngImagePlugin.PngStream(fp) as png:
while True:
cid, pos, length = png.read()
chunks.append(cid)
try:
s = png.call(cid, pos, length)
except EOFError:
break
png.crc(cid, s)
return chunks
def test_sanity(self):
# internal version number
self.assertRegex(Image.core.zlib_version, r"\d+\.\d+\.\d+(\.\d+)?$")
test_file = self.tempfile("temp.png")
hopper("RGB").save(test_file)
with Image.open(test_file) as im:
im.load()
self.assertEqual(im.mode, "RGB")
self.assertEqual(im.size, (128, 128))
self.assertEqual(im.format, "PNG")
self.assertEqual(im.get_format_mimetype(), "image/png")
for mode in ["1", "L", "P", "RGB", "I", "I;16"]:
im = hopper(mode)
im.save(test_file)
reloaded = Image.open(test_file)
if mode == "I;16":
reloaded = reloaded.convert(mode)
self.assert_image_equal(reloaded, im)
def test_invalid_file(self):
invalid_file = "Tests/images/flower.jpg"
self.assertRaises(SyntaxError, PngImagePlugin.PngImageFile, invalid_file)
def test_broken(self):
# Check reading of totally broken files. In this case, the test
# file was checked into Subversion as a text file.
test_file = "Tests/images/broken.png"
self.assertRaises(IOError, Image.open, test_file)
def test_bad_text(self):
# Make sure PIL can read malformed tEXt chunks (@PIL152)
im = load(HEAD + chunk(b"tEXt") + TAIL)
self.assertEqual(im.info, {})
im = load(HEAD + chunk(b"tEXt", b"spam") + TAIL)
self.assertEqual(im.info, {"spam": ""})
im = load(HEAD + chunk(b"tEXt", b"spam\0") + TAIL)
self.assertEqual(im.info, {"spam": ""})
im = load(HEAD + chunk(b"tEXt", b"spam\0egg") + TAIL)
self.assertEqual(im.info, {"spam": "egg"})
im = load(HEAD + chunk(b"tEXt", b"spam\0egg\0") + TAIL)
self.assertEqual(im.info, {"spam": "egg\x00"})
def test_bad_ztxt(self):
# Test reading malformed zTXt chunks (python-pillow/Pillow#318)
im = load(HEAD + chunk(b"zTXt") + TAIL)
self.assertEqual(im.info, {})
im = load(HEAD + chunk(b"zTXt", b"spam") + TAIL)
self.assertEqual(im.info, {"spam": ""})
im = load(HEAD + chunk(b"zTXt", b"spam\0") + TAIL)
self.assertEqual(im.info, {"spam": ""})
im = load(HEAD + chunk(b"zTXt", b"spam\0\0") + TAIL)
self.assertEqual(im.info, {"spam": ""})
im = load(HEAD + chunk(b"zTXt", b"spam\0\0" + zlib.compress(b"egg")[:1]) + TAIL)
self.assertEqual(im.info, {"spam": ""})
im = load(HEAD + chunk(b"zTXt", b"spam\0\0" + zlib.compress(b"egg")) + TAIL)
self.assertEqual(im.info, {"spam": "egg"})
def test_bad_itxt(self):
im = load(HEAD + chunk(b"iTXt") + TAIL)
self.assertEqual(im.info, {})
im = load(HEAD + chunk(b"iTXt", b"spam") + TAIL)
self.assertEqual(im.info, {})
im = load(HEAD + chunk(b"iTXt", b"spam\0") + TAIL)
self.assertEqual(im.info, {})
im = load(HEAD + chunk(b"iTXt", b"spam\0\x02") + TAIL)
self.assertEqual(im.info, {})
im = load(HEAD + chunk(b"iTXt", b"spam\0\0\0foo\0") + TAIL)
self.assertEqual(im.info, {})
im = load(HEAD + chunk(b"iTXt", b"spam\0\0\0en\0Spam\0egg") + TAIL)
self.assertEqual(im.info, {"spam": "egg"})
self.assertEqual(im.info["spam"].lang, "en")
self.assertEqual(im.info["spam"].tkey, "Spam")
im = load(
HEAD
+ chunk(b"iTXt", b"spam\0\1\0en\0Spam\0" + zlib.compress(b"egg")[:1])
+ TAIL
)
self.assertEqual(im.info, {"spam": ""})
im = load(
HEAD
+ chunk(b"iTXt", b"spam\0\1\1en\0Spam\0" + zlib.compress(b"egg"))
+ TAIL
)
self.assertEqual(im.info, {})
im = load(
HEAD
+ chunk(b"iTXt", b"spam\0\1\0en\0Spam\0" + zlib.compress(b"egg"))
+ TAIL
)
self.assertEqual(im.info, {"spam": "egg"})
self.assertEqual(im.info["spam"].lang, "en")
self.assertEqual(im.info["spam"].tkey, "Spam")
def test_interlace(self):
test_file = "Tests/images/pil123p.png"
im = Image.open(test_file)
self.assert_image(im, "P", (162, 150))
self.assertTrue(im.info.get("interlace"))
im.load()
test_file = "Tests/images/pil123rgba.png"
im = Image.open(test_file)
self.assert_image(im, "RGBA", (162, 150))
self.assertTrue(im.info.get("interlace"))
im.load()
def test_load_transparent_p(self):
test_file = "Tests/images/pil123p.png"
im = Image.open(test_file)
self.assert_image(im, "P", (162, 150))
im = im.convert("RGBA")
self.assert_image(im, "RGBA", (162, 150))
# image has 124 unique alpha values
self.assertEqual(len(im.getchannel("A").getcolors()), 124)
def test_load_transparent_rgb(self):
test_file = "Tests/images/rgb_trns.png"
im = Image.open(test_file)
self.assertEqual(im.info["transparency"], (0, 255, 52))
self.assert_image(im, "RGB", (64, 64))
im = im.convert("RGBA")
self.assert_image(im, "RGBA", (64, 64))
# image has 876 transparent pixels
self.assertEqual(im.getchannel("A").getcolors()[0][0], 876)
def test_save_p_transparent_palette(self):
in_file = "Tests/images/pil123p.png"
im = Image.open(in_file)
# 'transparency' contains a byte string with the opacity for
# each palette entry
self.assertEqual(len(im.info["transparency"]), 256)
test_file = self.tempfile("temp.png")
im.save(test_file)
# check if saved image contains same transparency
im = Image.open(test_file)
self.assertEqual(len(im.info["transparency"]), 256)
self.assert_image(im, "P", (162, 150))
im = im.convert("RGBA")
self.assert_image(im, "RGBA", (162, 150))
# image has 124 unique alpha values
self.assertEqual(len(im.getchannel("A").getcolors()), 124)
def test_save_p_single_transparency(self):
in_file = "Tests/images/p_trns_single.png"
im = Image.open(in_file)
# pixel value 164 is full transparent
self.assertEqual(im.info["transparency"], 164)
self.assertEqual(im.getpixel((31, 31)), 164)
test_file = self.tempfile("temp.png")
im.save(test_file)
# check if saved image contains same transparency
im = Image.open(test_file)
self.assertEqual(im.info["transparency"], 164)
self.assertEqual(im.getpixel((31, 31)), 164)
self.assert_image(im, "P", (64, 64))
im = im.convert("RGBA")
self.assert_image(im, "RGBA", (64, 64))
self.assertEqual(im.getpixel((31, 31)), (0, 255, 52, 0))
# image has 876 transparent pixels
self.assertEqual(im.getchannel("A").getcolors()[0][0], 876)
def test_save_p_transparent_black(self):
# check if solid black image with full transparency
# is supported (check for #1838)
im = Image.new("RGBA", (10, 10), (0, 0, 0, 0))
self.assertEqual(im.getcolors(), [(100, (0, 0, 0, 0))])
im = im.convert("P")
test_file = self.tempfile("temp.png")
im.save(test_file)
# check if saved image contains same transparency
im = Image.open(test_file)
self.assertEqual(len(im.info["transparency"]), 256)
self.assert_image(im, "P", (10, 10))
im = im.convert("RGBA")
self.assert_image(im, "RGBA", (10, 10))
self.assertEqual(im.getcolors(), [(100, (0, 0, 0, 0))])
def test_save_greyscale_transparency(self):
for mode, num_transparent in {"1": 1994, "L": 559, "I": 559}.items():
in_file = "Tests/images/" + mode.lower() + "_trns.png"
im = Image.open(in_file)
self.assertEqual(im.mode, mode)
self.assertEqual(im.info["transparency"], 255)
im_rgba = im.convert("RGBA")
self.assertEqual(im_rgba.getchannel("A").getcolors()[0][0], num_transparent)
test_file = self.tempfile("temp.png")
im.save(test_file)
test_im = Image.open(test_file)
self.assertEqual(test_im.mode, mode)
self.assertEqual(test_im.info["transparency"], 255)
self.assert_image_equal(im, test_im)
test_im_rgba = test_im.convert("RGBA")
self.assertEqual(
test_im_rgba.getchannel("A").getcolors()[0][0], num_transparent
)
def test_save_rgb_single_transparency(self):
in_file = "Tests/images/caption_6_33_22.png"
im = Image.open(in_file)
test_file = self.tempfile("temp.png")
im.save(test_file)
def test_load_verify(self):
# Check open/load/verify exception (@PIL150)
im = Image.open(TEST_PNG_FILE)
# Assert that there is no unclosed file warning
self.assert_warning(None, im.verify)
im = Image.open(TEST_PNG_FILE)
im.load()
self.assertRaises(RuntimeError, im.verify)
def test_verify_struct_error(self):
# Check open/load/verify exception (#1755)
# offsets to test, -10: breaks in i32() in read. (IOError)
# -13: breaks in crc, txt chunk.
# -14: malformed chunk
for offset in (-10, -13, -14):
with open(TEST_PNG_FILE, "rb") as f:
test_file = f.read()[:offset]
im = Image.open(BytesIO(test_file))
self.assertIsNotNone(im.fp)
self.assertRaises((IOError, SyntaxError), im.verify)
def test_verify_ignores_crc_error(self):
# check ignores crc errors in ancillary chunks
chunk_data = chunk(b"tEXt", b"spam")
broken_crc_chunk_data = chunk_data[:-1] + b"q" # break CRC
image_data = HEAD + broken_crc_chunk_data + TAIL
self.assertRaises(SyntaxError, PngImagePlugin.PngImageFile, BytesIO(image_data))
ImageFile.LOAD_TRUNCATED_IMAGES = True
try:
im = load(image_data)
self.assertIsNotNone(im)
finally:
ImageFile.LOAD_TRUNCATED_IMAGES = False
def test_verify_not_ignores_crc_error_in_required_chunk(self):
# check does not ignore crc errors in required chunks
image_data = MAGIC + IHDR[:-1] + b"q" + TAIL
ImageFile.LOAD_TRUNCATED_IMAGES = True
try:
self.assertRaises(
SyntaxError, PngImagePlugin.PngImageFile, BytesIO(image_data)
)
finally:
ImageFile.LOAD_TRUNCATED_IMAGES = False
def test_roundtrip_dpi(self):
# Check dpi roundtripping
im = Image.open(TEST_PNG_FILE)
im = roundtrip(im, dpi=(100, 100))
self.assertEqual(im.info["dpi"], (100, 100))
def test_load_dpi_rounding(self):
# Round up
with Image.open(TEST_PNG_FILE) as im:
self.assertEqual(im.info["dpi"], (96, 96))
# Round down
with Image.open("Tests/images/icc_profile_none.png") as im:
self.assertEqual(im.info["dpi"], (72, 72))
def test_save_dpi_rounding(self):
im = Image.open(TEST_PNG_FILE)
im = roundtrip(im, dpi=(72.2, 72.2))
self.assertEqual(im.info["dpi"], (72, 72))
im = roundtrip(im, dpi=(72.8, 72.8))
self.assertEqual(im.info["dpi"], (73, 73))
def test_roundtrip_text(self):
# Check text roundtripping
im = Image.open(TEST_PNG_FILE)
info = PngImagePlugin.PngInfo()
info.add_text("TXT", "VALUE")
info.add_text("ZIP", "VALUE", zip=True)
im = roundtrip(im, pnginfo=info)
self.assertEqual(im.info, {"TXT": "VALUE", "ZIP": "VALUE"})
self.assertEqual(im.text, {"TXT": "VALUE", "ZIP": "VALUE"})
def test_roundtrip_itxt(self):
# Check iTXt roundtripping
im = Image.new("RGB", (32, 32))
info = PngImagePlugin.PngInfo()
info.add_itxt("spam", "Eggs", "en", "Spam")
info.add_text("eggs", PngImagePlugin.iTXt("Spam", "en", "Eggs"), zip=True)
im = roundtrip(im, pnginfo=info)
self.assertEqual(im.info, {"spam": "Eggs", "eggs": "Spam"})
self.assertEqual(im.text, {"spam": "Eggs", "eggs": "Spam"})
self.assertEqual(im.text["spam"].lang, "en")
self.assertEqual(im.text["spam"].tkey, "Spam")
self.assertEqual(im.text["eggs"].lang, "en")
self.assertEqual(im.text["eggs"].tkey, "Eggs")
def test_nonunicode_text(self):
# Check so that non-Unicode text is saved as a tEXt rather than iTXt
im = Image.new("RGB", (32, 32))
info = PngImagePlugin.PngInfo()
info.add_text("Text", "Ascii")
im = roundtrip(im, pnginfo=info)
self.assertIsInstance(im.info["Text"], str)
def test_unicode_text(self):
# Check preservation of non-ASCII characters on Python 3
# This cannot really be meaningfully tested on Python 2,
# since it didn't preserve charsets to begin with.
def rt_text(value):
im = Image.new("RGB", (32, 32))
info = PngImagePlugin.PngInfo()
info.add_text("Text", value)
im = roundtrip(im, pnginfo=info)
self.assertEqual(im.info, {"Text": value})
if py3:
rt_text(" Aa" + chr(0xA0) + chr(0xC4) + chr(0xFF)) # Latin1
rt_text(chr(0x400) + chr(0x472) + chr(0x4FF)) # Cyrillic
rt_text(
chr(0x4E00)
+ chr(0x66F0)
+ chr(0x9FBA) # CJK
+ chr(0x3042)
+ chr(0xAC00)
)
rt_text("A" + chr(0xC4) + chr(0x472) + chr(0x3042)) # Combined
def test_scary(self):
# Check reading of evil PNG file. For information, see:
# http://scary.beasts.org/security/CESA-2004-001.txt
# The first byte is removed from pngtest_bad.png
# to avoid classification as malware.
with open("Tests/images/pngtest_bad.png.bin", "rb") as fd:
data = b"\x89" + fd.read()
pngfile = BytesIO(data)
self.assertRaises(IOError, Image.open, pngfile)
def test_trns_rgb(self):
# Check writing and reading of tRNS chunks for RGB images.
# Independent file sample provided by Sebastian Spaeth.
test_file = "Tests/images/caption_6_33_22.png"
im = Image.open(test_file)
self.assertEqual(im.info["transparency"], (248, 248, 248))
# check saving transparency by default
im = roundtrip(im)
self.assertEqual(im.info["transparency"], (248, 248, 248))
im = roundtrip(im, transparency=(0, 1, 2))
self.assertEqual(im.info["transparency"], (0, 1, 2))
def test_trns_p(self):
# Check writing a transparency of 0, issue #528
im = hopper("P")
im.info["transparency"] = 0
f = self.tempfile("temp.png")
im.save(f)
im2 = Image.open(f)
self.assertIn("transparency", im2.info)
self.assert_image_equal(im2.convert("RGBA"), im.convert("RGBA"))
def test_trns_null(self):
# Check reading images with null tRNS value, issue #1239
test_file = "Tests/images/tRNS_null_1x1.png"
with Image.open(test_file) as im:
self.assertEqual(im.info["transparency"], 0)
def test_save_icc_profile(self):
with Image.open("Tests/images/icc_profile_none.png") as im:
self.assertIsNone(im.info["icc_profile"])
with Image.open("Tests/images/icc_profile.png") as with_icc:
expected_icc = with_icc.info["icc_profile"]
im = roundtrip(im, icc_profile=expected_icc)
self.assertEqual(im.info["icc_profile"], expected_icc)
def test_discard_icc_profile(self):
im = Image.open("Tests/images/icc_profile.png")
im = roundtrip(im, icc_profile=None)
self.assertNotIn("icc_profile", im.info)
def test_roundtrip_icc_profile(self):
im = Image.open("Tests/images/icc_profile.png")
expected_icc = im.info["icc_profile"]
im = roundtrip(im)
self.assertEqual(im.info["icc_profile"], expected_icc)
def test_roundtrip_no_icc_profile(self):
im = Image.open("Tests/images/icc_profile_none.png")
self.assertIsNone(im.info["icc_profile"])
im = roundtrip(im)
self.assertNotIn("icc_profile", im.info)
def test_repr_png(self):
im = hopper()
repr_png = Image.open(BytesIO(im._repr_png_()))
self.assertEqual(repr_png.format, "PNG")
self.assert_image_equal(im, repr_png)
def test_chunk_order(self):
im = Image.open("Tests/images/icc_profile.png")
test_file = self.tempfile("temp.png")
im.convert("P").save(test_file, dpi=(100, 100))
chunks = self.get_chunks(test_file)
# https://www.w3.org/TR/PNG/#5ChunkOrdering
# IHDR - shall be first
self.assertEqual(chunks.index(b"IHDR"), 0)
# PLTE - before first IDAT
self.assertLess(chunks.index(b"PLTE"), chunks.index(b"IDAT"))
# iCCP - before PLTE and IDAT
self.assertLess(chunks.index(b"iCCP"), chunks.index(b"PLTE"))
self.assertLess(chunks.index(b"iCCP"), chunks.index(b"IDAT"))
# tRNS - after PLTE, before IDAT
self.assertGreater(chunks.index(b"tRNS"), chunks.index(b"PLTE"))
self.assertLess(chunks.index(b"tRNS"), chunks.index(b"IDAT"))
# pHYs - before IDAT
self.assertLess(chunks.index(b"pHYs"), chunks.index(b"IDAT"))
def test_getchunks(self):
im = hopper()
chunks = PngImagePlugin.getchunks(im)
self.assertEqual(len(chunks), 3)
def test_textual_chunks_after_idat(self):
im = Image.open("Tests/images/hopper.png")
self.assertIn("comment", im.text.keys())
for k, v in {
"date:create": "2014-09-04T09:37:08+03:00",
"date:modify": "2014-09-04T09:37:08+03:00",
}.items():
self.assertEqual(im.text[k], v)
# Raises a SyntaxError in load_end
im = Image.open("Tests/images/broken_data_stream.png")
with self.assertRaises(IOError):
self.assertIsInstance(im.text, dict)
# Raises a UnicodeDecodeError in load_end
im = Image.open("Tests/images/truncated_image.png")
# The file is truncated
self.assertRaises(IOError, lambda: im.text)
ImageFile.LOAD_TRUNCATED_IMAGES = True
self.assertIsInstance(im.text, dict)
ImageFile.LOAD_TRUNCATED_IMAGES = False
# Raises an EOFError in load_end
im = Image.open("Tests/images/hopper_idat_after_image_end.png")
self.assertEqual(im.text, {"TXT": "VALUE", "ZIP": "VALUE"})
def test_exif(self):
im = Image.open("Tests/images/exif.png")
exif = im._getexif()
self.assertEqual(exif[274], 1)
def test_exif_save(self):
im = Image.open("Tests/images/exif.png")
test_file = self.tempfile("temp.png")
im.save(test_file)
with Image.open(test_file) as reloaded:
exif = reloaded._getexif()
self.assertEqual(exif[274], 1)
def test_exif_from_jpg(self):
im = Image.open("Tests/images/pil_sample_rgb.jpg")
test_file = self.tempfile("temp.png")
im.save(test_file)
with Image.open(test_file) as reloaded:
exif = reloaded._getexif()
self.assertEqual(exif[305], "Adobe Photoshop CS Macintosh")
def test_exif_argument(self):
im = Image.open(TEST_PNG_FILE)
test_file = self.tempfile("temp.png")
im.save(test_file, exif=b"exifstring")
with Image.open(test_file) as reloaded:
self.assertEqual(reloaded.info["exif"], b"Exif\x00\x00exifstring")
@unittest.skipUnless(
HAVE_WEBP and _webp.HAVE_WEBPANIM, "WebP support not installed with animation"
)
def test_apng(self):
im = Image.open("Tests/images/iss634.apng")
self.assertEqual(im.get_format_mimetype(), "image/apng")
# This also tests reading unknown PNG chunks (fcTL and fdAT) in load_end
expected = Image.open("Tests/images/iss634.webp")
self.assert_image_similar(im, expected, 0.23)
@unittest.skipIf(is_win32(), "requires Unix or macOS")
class TestTruncatedPngPLeaks(PillowLeakTestCase):
mem_limit = 2 * 1024 # max increase in K
iterations = 100 # Leak is 56k/iteration, this will leak 5.6megs
def setUp(self):
if "zip_encoder" not in codecs or "zip_decoder" not in codecs:
self.skipTest("zip/deflate support not available")
def test_leak_load(self):
with open("Tests/images/hopper.png", "rb") as f:
DATA = BytesIO(f.read(16 * 1024))
ImageFile.LOAD_TRUNCATED_IMAGES = True
with Image.open(DATA) as im:
im.load()
def core():
with Image.open(DATA) as im:
im.load()
try:
self._test_leak(core)
finally:
ImageFile.LOAD_TRUNCATED_IMAGES = False