cpython/Lib/test/test_mmap.py

277 lines
8.4 KiB
Python

from 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')
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 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()
del m, f
verify(open(TESTFN).read() == '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
# 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)
finally:
try:
os.unlink(TESTFN)
except OSError:
pass
print ' Test passed'
test_both()