from __future__ import absolute_import

import glob

import os

import shutil

import tempfile

import unittest

from mercurial import (

    util,

)

atomictempfile = util.atomictempfile

class testatomictempfile(unittest.TestCase):

    def setUp(self):

        self._testdir = tempfile.mkdtemp('atomictempfiletest')

        self._filename = os.path.join(self._testdir, 'testfilename')

    def tearDown(self):

        shutil.rmtree(self._testdir, True)

    def testsimple(self):

        file = atomictempfile(self._filename)

        self.assertFalse(os.path.isfile(self._filename))

        tempfilename = file._tempname

        self.assertTrue(tempfilename in glob.glob(

            os.path.join(self._testdir, '.testfilename-*')))

        file.write(b'argh\n')

        file.close()

        self.assertTrue(os.path.isfile(self._filename))

        self.assertTrue(tempfilename not in glob.glob(

            os.path.join(self._testdir, '.testfilename-*')))

    # discard() removes the temp file without making the write permanent

    def testdiscard(self):

        file = atomictempfile(self._filename)

        (dir, basename) = os.path.split(file._tempname)

        file.write(b'yo\n')

        file.discard()

        self.assertFalse(os.path.isfile(self._filename))

        self.assertTrue(basename not in os.listdir('.'))

    # if a programmer screws up and passes bad args to atomictempfile, they

    # get a plain ordinary TypeError, not infinite recursion

    def testoops(self):

        with self.assertRaises(TypeError):

            atomictempfile()

    # checkambig=True avoids ambiguity of timestamp

    def testcheckambig(self):

        def atomicwrite(checkambig):

            f = atomictempfile(self._filename, checkambig=checkambig)

            f.write('FOO')

            f.close()

        # try some times, because reproduction of ambiguity depends on

        # "filesystem time"

        for i in xrange(5):

            atomicwrite(False)

            oldstat = os.stat(self._filename)

            if oldstat.st_ctime != oldstat.st_mtime:

                # subsequent changing never causes ambiguity

                continue

            repetition = 3

            # repeat atomic write with checkambig=True, to examine

            # whether st_mtime is advanced multiple times as expected

            for j in xrange(repetition):

                atomicwrite(True)

            newstat = os.stat(self._filename)

            if oldstat.st_ctime != newstat.st_ctime:

                # timestamp ambiguity was naturally avoided while repetition

                continue

            # st_mtime should be advanced "repetition" times, because

            # all atomicwrite() occurred at same time (in sec)

            self.assertTrue(newstat.st_mtime ==

                            ((oldstat.st_mtime + repetition) & 0x7fffffff))

            # no more examination is needed, if assumption above is true

            break

        else:

            # This platform seems too slow to examine anti-ambiguity

            # of file timestamp (or test happened to be executed at

            # bad timing). Exit silently in this case, because running

            # on other faster platforms can detect problems

            pass

    def testread(self):

        with open(self._filename, 'wb') as f:

            f.write(b'foobar\n')

        file = atomictempfile(self._filename, mode='rb')

        self.assertTrue(file.read(), b'foobar\n')

        file.discard()

    def testcontextmanagersuccess(self):

        """When the context closes, the file is closed"""

        with atomictempfile('foo') as f:

            self.assertFalse(os.path.isfile('foo'))

            f.write(b'argh\n')

        self.assertTrue(os.path.isfile('foo'))

    def testcontextmanagerfailure(self):

        """On exception, the file is discarded"""

        try:

            with atomictempfile('foo') as f:

                self.assertFalse(os.path.isfile('foo'))

                f.write(b'argh\n')

                raise ValueError

        except ValueError:

            pass

        self.assertFalse(os.path.isfile('foo'))

if __name__ == '__main__':

    import silenttestrunner

    silenttestrunner.main(__name__)