/SiRFLive/PythonStdLib/test/test_mmap.py

from test.test_support import verify, vereq, TESTFN

import mmap

import os, re



PAGESIZE = mmap.PAGESIZE



def test_both():

    "Test mmap module on Unix systems and Windows"



    # Create a file to be mmap'ed.

    if os.path.exists(TESTFN):

        os.unlink(TESTFN)

    f = open(TESTFN, 'w+')



    try:    # unlink TESTFN no matter what

        # Write 2 pages worth of data to the file

        f.write('\0'* PAGESIZE)

        f.write('foo')

        f.write('\0'* (PAGESIZE-3) )

        f.flush()

        m = mmap.mmap(f.fileno(), 2 * PAGESIZE)

        f.close()



        # Simple sanity checks



        print type(m)  # SF bug 128713:  segfaulted on Linux

        print '  Position of foo:', m.find('foo') / float(PAGESIZE), 'pages'

        vereq(m.find('foo'), PAGESIZE)



        print '  Length of file:', len(m) / float(PAGESIZE), 'pages'

        vereq(len(m), 2*PAGESIZE)



        print '  Contents of byte 0:', repr(m[0])

        vereq(m[0], '\0')

        print '  Contents of first 3 bytes:', repr(m[0:3])

        vereq(m[0:3], '\0\0\0')



        # Modify the file's content

        print "\n  Modifying file's content..."

        m[0] = '3'

        m[PAGESIZE +3: PAGESIZE +3+3] = 'bar'



        # Check that the modification worked

        print '  Contents of byte 0:', repr(m[0])

        vereq(m[0], '3')

        print '  Contents of first 3 bytes:', repr(m[0:3])

        vereq(m[0:3], '3\0\0')

        print '  Contents of second page:',  repr(m[PAGESIZE-1 : PAGESIZE + 7])

        vereq(m[PAGESIZE-1 : PAGESIZE + 7], '\0foobar\0')



        m.flush()



        # Test doing a regular expression match in an mmap'ed file

        match = re.search('[A-Za-z]+', m)

        if match is None:

            print '  ERROR: regex match on mmap failed!'

        else:

            start, end = match.span(0)

            length = end - start



            print '  Regex match on mmap (page start, length of match):',

            print start / float(PAGESIZE), length



            vereq(start, PAGESIZE)

            vereq(end, PAGESIZE + 6)



        # test seeking around (try to overflow the seek implementation)

        m.seek(0,0)

        print '  Seek to zeroth byte'

        vereq(m.tell(), 0)

        m.seek(42,1)

        print '  Seek to 42nd byte'

        vereq(m.tell(), 42)

        m.seek(0,2)

        print '  Seek to last byte'

        vereq(m.tell(), len(m))



        print '  Try to seek to negative position...'

        try:

            m.seek(-1)

        except ValueError:

            pass

        else:

            verify(0, 'expected a ValueError but did not get it')



        print '  Try to seek beyond end of mmap...'

        try:

            m.seek(1,2)

        except ValueError:

            pass

        else:

            verify(0, 'expected a ValueError but did not get it')



        print '  Try to seek to negative position...'

        try:

            m.seek(-len(m)-1,2)

        except ValueError:

            pass

        else:

            verify(0, 'expected a ValueError but did not get it')



        # Try resizing map

        print '  Attempting resize()'

        try:

            m.resize(512)

        except SystemError:

            # resize() not supported

            # No messages are printed, since the output of this test suite

            # would then be different across platforms.

            pass

        else:

            # resize() is supported

            verify(len(m) == 512,

                    "len(m) is %d, but expecting 512" % (len(m),) )

            # Check that we can no longer seek beyond the new size.

            try:

                m.seek(513,0)

            except ValueError:

                pass

            else:

                verify(0, 'Could seek beyond the new size')



            # Check that the underlying file is truncated too

            # (bug #728515)

            f = open(TESTFN)

            f.seek(0, 2)

            verify(f.tell() == 512, 'Underlying file not truncated')

            f.close()

            verify(m.size() == 512, 'New size not reflected in file')



        m.close()



    finally:

        try:

            f.close()

        except OSError:

            pass

        try:

            os.unlink(TESTFN)

        except OSError:

            pass



    # Test for "access" keyword parameter

    try:

        mapsize = 10

        print "  Creating", mapsize, "byte test data file."

        open(TESTFN, "wb").write("a"*mapsize)

        print "  Opening mmap with access=ACCESS_READ"

        f = open(TESTFN, "rb")

        m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_READ)

        verify(m[:] == 'a'*mapsize, "Readonly memory map data incorrect.")



        print "  Ensuring that readonly mmap can't be slice assigned."

        try:

            m[:] = 'b'*mapsize

        except TypeError:

            pass

        else:

            verify(0, "Able to write to readonly memory map")



        print "  Ensuring that readonly mmap can't be item assigned."

        try:

            m[0] = 'b'

        except TypeError:

            pass

        else:

            verify(0, "Able to write to readonly memory map")



        print "  Ensuring that readonly mmap can't be write() to."

        try:

            m.seek(0,0)

            m.write('abc')

        except TypeError:

            pass

        else:

            verify(0, "Able to write to readonly memory map")



        print "  Ensuring that readonly mmap can't be write_byte() to."

        try:

            m.seek(0,0)

            m.write_byte('d')

        except TypeError:

            pass

        else:

            verify(0, "Able to write to readonly memory map")



        print "  Ensuring that readonly mmap can't be resized."

        try:

            m.resize(2*mapsize)

        except SystemError:   # resize is not universally supported

            pass

        except TypeError:

            pass

        else:

            verify(0, "Able to resize readonly memory map")

        del m, f

        verify(open(TESTFN, "rb").read() == 'a'*mapsize,

               "Readonly memory map data file was modified")



        print "  Opening mmap with size too big"

        import sys

        f = open(TESTFN, "r+b")

        try:

            m = mmap.mmap(f.fileno(), mapsize+1)

        except ValueError:

            # we do not expect a ValueError on Windows

            # CAUTION:  This also changes the size of the file on disk, and

            # later tests assume that the length hasn't changed.  We need to

            # repair that.

            if sys.platform.startswith('win'):

                verify(0, "Opening mmap with size+1 should work on Windows.")

        else:

            # we expect a ValueError on Unix, but not on Windows

            if not sys.platform.startswith('win'):

                verify(0, "Opening mmap with size+1 should raise ValueError.")

            m.close()

        f.close()

        if sys.platform.startswith('win'):

            # Repair damage from the resizing test.

            f = open(TESTFN, 'r+b')

            f.truncate(mapsize)

            f.close()



        print "  Opening mmap with access=ACCESS_WRITE"

        f = open(TESTFN, "r+b")

        m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_WRITE)

        print "  Modifying write-through memory map."

        m[:] = 'c'*mapsize

        verify(m[:] == 'c'*mapsize,

               "Write-through memory map memory not updated properly.")

        m.flush()

        m.close()

        f.close()

        f = open(TESTFN, 'rb')

        stuff = f.read()

        f.close()

        verify(stuff == 'c'*mapsize,

               "Write-through memory map data file not updated properly.")



        print "  Opening mmap with access=ACCESS_COPY"

        f = open(TESTFN, "r+b")

        m = mmap.mmap(f.fileno(), mapsize, access=mmap.ACCESS_COPY)

        print "  Modifying copy-on-write memory map."

        m[:] = 'd'*mapsize

        verify(m[:] == 'd' * mapsize,

               "Copy-on-write memory map data not written correctly.")

        m.flush()

        verify(open(TESTFN, "rb").read() == 'c'*mapsize,

               "Copy-on-write test data file should not be modified.")

        try:

            print "  Ensuring copy-on-write maps cannot be resized."

            m.resize(2*mapsize)

        except TypeError:

            pass

        else:

            verify(0, "Copy-on-write mmap resize did not raise exception.")

        del m, f

        try:

            print "  Ensuring invalid access parameter raises exception."

            f = open(TESTFN, "r+b")

            m = mmap.mmap(f.fileno(), mapsize, access=4)

        except ValueError:

            pass

        else:

            verify(0, "Invalid access code should have raised exception.")



        if os.name == "posix":

            # Try incompatible flags, prot and access parameters.

            f = open(TESTFN, "r+b")

            try:

                m = mmap.mmap(f.fileno(), mapsize, flags=mmap.MAP_PRIVATE,

                              prot=mmap.PROT_READ, access=mmap.ACCESS_WRITE)

            except ValueError:

                pass

            else:

                verify(0, "Incompatible parameters should raise ValueError.")

            f.close()

    finally:

        try:

            os.unlink(TESTFN)

        except OSError:

            pass



    print '  Try opening a bad file descriptor...'

    try:

        mmap.mmap(-1, 4096)

    except mmap.error:

        pass

    else:

        verify(0, 'expected a mmap.error but did not get it')



    # Do a tougher .find() test.  SF bug 515943 pointed out that, in 2.2,

    # searching for data with embedded \0 bytes didn't work.

    f = open(TESTFN, 'w+')



    try:    # unlink TESTFN no matter what

        data = 'aabaac\x00deef\x00\x00aa\x00'

        n = len(data)

        f.write(data)

        f.flush()

        m = mmap.mmap(f.fileno(), n)

        f.close()



        for start in range(n+1):

            for finish in range(start, n+1):

                slice = data[start : finish]

                vereq(m.find(slice), data.find(slice))

                vereq(m.find(slice + 'x'), -1)

        m.close()



    finally:

        os.unlink(TESTFN)



    # make sure a double close doesn't crash on Solaris (Bug# 665913)

    f = open(TESTFN, 'w+')



    try:    # unlink TESTFN no matter what

        f.write(2**16 * 'a') # Arbitrary character

        f.close()



        f = open(TESTFN)

        mf = mmap.mmap(f.fileno(), 2**16, access=mmap.ACCESS_READ)

        mf.close()

        mf.close()

        f.close()



    finally:

        os.unlink(TESTFN)





    print ' Test passed'



test_both()