"""Test script for the gzip module.
"""

import array
import functools
import io
import os
import pathlib
import struct
import sys
import unittest
from subprocess import PIPE, Popen
from test import support
from test.support import _4G, bigmemtest
from test.support.script_helper import assert_python_ok, assert_python_failure

gzip = support.import_module('gzip')

data1 = b"""  int length=DEFAULTALLOC, err = Z_OK;
  PyObject *RetVal;
  int flushmode = Z_FINISH;
  unsigned long start_total_out;

"""

data2 = b"""/* zlibmodule.c -- gzip-compatible data compression */
/* See http://www.gzip.org/zlib/
/* See http://www.winimage.com/zLibDll for Windows */
"""


TEMPDIR = os.path.abspath(support.TESTFN) + '-gzdir'


class UnseekableIO(io.BytesIO):
    def seekable(self):
        return False

    def tell(self):
        raise io.UnsupportedOperation

    def seek(self, *args):
        raise io.UnsupportedOperation


class BaseTest(unittest.TestCase):
    filename = support.TESTFN

    def setUp(self):
        support.unlink(self.filename)

    def tearDown(self):
        support.unlink(self.filename)


class TestGzip(BaseTest):
    def write_and_read_back(self, data, mode='b'):
        b_data = bytes(data)
        with gzip.GzipFile(self.filename, 'w'+mode) as f:
            l = f.write(data)
        self.assertEqual(l, len(b_data))
        with gzip.GzipFile(self.filename, 'r'+mode) as f:
            self.assertEqual(f.read(), b_data)

    def test_write(self):
        with gzip.GzipFile(self.filename, 'wb') as f:
            f.write(data1 * 50)

            # Try flush and fileno.
            f.flush()
            f.fileno()
            if hasattr(os, 'fsync'):
                os.fsync(f.fileno())
            f.close()

        # Test multiple close() calls.
        f.close()

    def test_write_read_with_pathlike_file(self):
        filename = pathlib.Path(self.filename)
        with gzip.GzipFile(filename, 'w') as f:
            f.write(data1 * 50)
        self.assertIsInstance(f.name, str)
        with gzip.GzipFile(filename, 'a') as f:
            f.write(data1)
        with gzip.GzipFile(filename) as f:
            d = f.read()
        self.assertEqual(d, data1 * 51)
        self.assertIsInstance(f.name, str)

    # The following test_write_xy methods test that write accepts
    # the corresponding bytes-like object type as input
    # and that the data written equals bytes(xy) in all cases.
    def test_write_memoryview(self):
        self.write_and_read_back(memoryview(data1 * 50))
        m = memoryview(bytes(range(256)))
        data = m.cast('B', shape=[8,8,4])
        self.write_and_read_back(data)

    def test_write_bytearray(self):
        self.write_and_read_back(bytearray(data1 * 50))

    def test_write_array(self):
        self.write_and_read_back(array.array('I', data1 * 40))

    def test_write_incompatible_type(self):
        # Test that non-bytes-like types raise TypeError.
        # Issue #21560: attempts to write incompatible types
        # should not affect the state of the fileobject
        with gzip.GzipFile(self.filename, 'wb') as f:
            with self.assertRaises(TypeError):
                f.write('')
            with self.assertRaises(TypeError):
                f.write([])
            f.write(data1)
        with gzip.GzipFile(self.filename, 'rb') as f:
            self.assertEqual(f.read(), data1)

    def test_read(self):
        self.test_write()
        # Try reading.
        with gzip.GzipFile(self.filename, 'r') as f:
            d = f.read()
        self.assertEqual(d, data1*50)

    def test_read1(self):
        self.test_write()
        blocks = []
        nread = 0
        with gzip.GzipFile(self.filename, 'r') as f:
            while True:
                d = f.read1()
                if not d:
                    break
                blocks.append(d)
                nread += len(d)
                # Check that position was updated correctly (see issue10791).
                self.assertEqual(f.tell(), nread)
        self.assertEqual(b''.join(blocks), data1 * 50)

    @bigmemtest(size=_4G, memuse=1)
    def test_read_large(self, size):
        # Read chunk size over UINT_MAX should be supported, despite zlib's
        # limitation per low-level call
        compressed = gzip.compress(data1, compresslevel=1)
        f = gzip.GzipFile(fileobj=io.BytesIO(compressed), mode='rb')
        self.assertEqual(f.read(size), data1)

    def test_io_on_closed_object(self):
        # Test that I/O operations on closed GzipFile objects raise a
        # ValueError, just like the corresponding functions on file objects.

        # Write to a file, open it for reading, then close it.
        self.test_write()
        f = gzip.GzipFile(self.filename, 'r')
        fileobj = f.fileobj
        self.assertFalse(fileobj.closed)
        f.close()
        self.assertTrue(fileobj.closed)
        with self.assertRaises(ValueError):
            f.read(1)
        with self.assertRaises(ValueError):
            f.seek(0)
        with self.assertRaises(ValueError):
            f.tell()
        # Open the file for writing, then close it.
        f = gzip.GzipFile(self.filename, 'w')
        fileobj = f.fileobj
        self.assertFalse(fileobj.closed)
        f.close()
        self.assertTrue(fileobj.closed)
        with self.assertRaises(ValueError):
            f.write(b'')
        with self.assertRaises(ValueError):
            f.flush()

    def test_append(self):
        self.test_write()
        # Append to the previous file
        with gzip.GzipFile(self.filename, 'ab') as f:
            f.write(data2 * 15)

        with gzip.GzipFile(self.filename, 'rb') as f:
            d = f.read()
        self.assertEqual(d, (data1*50) + (data2*15))

    def test_many_append(self):
        # Bug #1074261 was triggered when reading a file that contained
        # many, many members.  Create such a file and verify that reading it
        # works.
        with gzip.GzipFile(self.filename, 'wb', 9) as f:
            f.write(b'a')
        for i in range(0, 200):
            with gzip.GzipFile(self.filename, "ab", 9) as f: # append
                f.write(b'a')

        # Try reading the file
        with gzip.GzipFile(self.filename, "rb") as zgfile:
            contents = b""
            while 1:
                ztxt = zgfile.read(8192)
                contents += ztxt
                if not ztxt: break
        self.assertEqual(contents, b'a'*201)

    def test_exclusive_write(self):
        with gzip.GzipFile(self.filename, 'xb') as f:
            f.write(data1 * 50)
        with gzip.GzipFile(self.filename, 'rb') as f:
            self.assertEqual(f.read(), data1 * 50)
        with self.assertRaises(FileExistsError):
            gzip.GzipFile(self.filename, 'xb')

    def test_buffered_reader(self):
        # Issue #7471: a GzipFile can be wrapped in a BufferedReader for
        # performance.
        self.test_write()

        with gzip.GzipFile(self.filename, 'rb') as f:
            with io.BufferedReader(f) as r:
                lines = [line for line in r]

        self.assertEqual(lines, 50 * data1.splitlines(keepends=True))

    def test_readline(self):
        self.test_write()
        # Try .readline() with varying line lengths

        with gzip.GzipFile(self.filename, 'rb') as f:
            line_length = 0
            while 1:
                L = f.readline(line_length)
                if not L and line_length != 0: break
                self.assertTrue(len(L) <= line_length)
                line_length = (line_length + 1) % 50

    def test_readlines(self):
        self.test_write()
        # Try .readlines()

        with gzip.GzipFile(self.filename, 'rb') as f:
            L = f.readlines()

        with gzip.GzipFile(self.filename, 'rb') as f:
            while 1:
                L = f.readlines(150)
                if L == []: break

    def test_seek_read(self):
        self.test_write()
        # Try seek, read test

        with gzip.GzipFile(self.filename) as f:
            while 1:
                oldpos = f.tell()
                line1 = f.readline()
                if not line1: break
                newpos = f.tell()
                f.seek(oldpos)  # negative seek
                if len(line1)>10:
                    amount = 10
                else:
                    amount = len(line1)
                line2 = f.read(amount)
                self.assertEqual(line1[:amount], line2)
                f.seek(newpos)  # positive seek

    def test_seek_whence(self):
        self.test_write()
        # Try seek(whence=1), read test

        with gzip.GzipFile(self.filename) as f:
            f.read(10)
            f.seek(10, whence=1)
            y = f.read(10)
        self.assertEqual(y, data1[20:30])

    def test_seek_write(self):
        # Try seek, write test
        with gzip.GzipFile(self.filename, 'w') as f:
            for pos in range(0, 256, 16):
                f.seek(pos)
                f.write(b'GZ\n')

    def test_mode(self):
        self.test_write()
        with gzip.GzipFile(self.filename, 'r') as f:
            self.assertEqual(f.myfileobj.mode, 'rb')
        support.unlink(self.filename)
        with gzip.GzipFile(self.filename, 'x') as f:
            self.assertEqual(f.myfileobj.mode, 'xb')

    def test_1647484(self):
        for mode in ('wb', 'rb'):
            with gzip.GzipFile(self.filename, mode) as f:
                self.assertTrue(hasattr(f, "name"))
                self.assertEqual(f.name, self.filename)

    def test_paddedfile_getattr(self):
        self.test_write()
        with gzip.GzipFile(self.filename, 'rb') as f:
            self.assertTrue(hasattr(f.fileobj, "name"))
            self.assertEqual(f.fileobj.name, self.filename)

    def test_mtime(self):
        mtime = 123456789
        with gzip.GzipFile(self.filename, 'w', mtime = mtime) as fWrite:
            fWrite.write(data1)
        with gzip.GzipFile(self.filename) as fRead:
            self.assertTrue(hasattr(fRead, 'mtime'))
            self.assertIsNone(fRead.mtime)
            dataRead = fRead.read()
            self.assertEqual(dataRead, data1)
            self.assertEqual(fRead.mtime, mtime)

    def test_metadata(self):
        mtime = 123456789

        with gzip.GzipFile(self.filename, 'w', mtime = mtime) as fWrite:
            fWrite.write(data1)

        with open(self.filename, 'rb') as fRead:
            # see RFC 1952: http://www.faqs.org/rfcs/rfc1952.html

            idBytes = fRead.read(2)
            self.assertEqual(idBytes, b'\x1f\x8b') # gzip ID

            cmByte = fRead.read(1)
            self.assertEqual(cmByte, b'\x08') # deflate

            flagsByte = fRead.read(1)
            self.assertEqual(flagsByte, b'\x08') # only the FNAME flag is set

            mtimeBytes = fRead.read(4)
            self.assertEqual(mtimeBytes, struct.pack('<i', mtime)) # little-endian

            xflByte = fRead.read(1)
            self.assertEqual(xflByte, b'\x02') # maximum compression

            osByte = fRead.read(1)
            self.assertEqual(osByte, b'\xff') # OS "unknown" (OS-independent)

            # Since the FNAME flag is set, the zero-terminated filename follows.
            # RFC 1952 specifies that this is the name of the input file, if any.
            # However, the gzip module defaults to storing the name of the output