circuitpython/tests/extmod/vfs_lfs_mtime.py
Damien George 2acc087880 extmod/vfs_lfs: Add mtime support to littlefs files.
This commit adds support for modification time of files on littlefs v2
filesystems, using file attributes.  For some background see issue #6114.

Features/properties of this implementation:
- Only supported on littlefs2 (not littlefs1).
- Uses littlefs2's general file attributes to store the timestamp.
- The timestamp is 64-bits and stores nanoseconds since 1970/1/1 (if the
  range to the year 2554 is not enough then additional bits can be added to
  this timestamp by adding another file attribute).
- mtime is enabled by default but can be disabled in the constructor, eg:
  uos.mount(uos.VfsLfs2(bdev, mtime=False), '/flash')
- It's fully backwards compatible, existing littlefs2 filesystems will work
  without reformatting and timestamps will be added transparently to
  existing files (once they are opened for writing).
- Files without timestamps will open correctly, and stat will just return 0
  for their timestamp.
- mtime can be disabled or enabled each mount time and timestamps will only
  be updated if mtime is enabled (otherwise they will be untouched).

Signed-off-by: Damien George <damien@micropython.org>
2020-08-25 17:35:19 +10:00

99 lines
2.6 KiB
Python

# Test for VfsLfs using a RAM device, mtime feature
try:
import utime, uos
utime.sleep
uos.VfsLfs2
except (ImportError, AttributeError):
print("SKIP")
raise SystemExit
class RAMBlockDevice:
ERASE_BLOCK_SIZE = 1024
def __init__(self, blocks):
self.data = bytearray(blocks * self.ERASE_BLOCK_SIZE)
def readblocks(self, block, buf, off):
addr = block * self.ERASE_BLOCK_SIZE + off
for i in range(len(buf)):
buf[i] = self.data[addr + i]
def writeblocks(self, block, buf, off):
addr = block * self.ERASE_BLOCK_SIZE + off
for i in range(len(buf)):
self.data[addr + i] = buf[i]
def ioctl(self, op, arg):
if op == 4: # block count
return len(self.data) // self.ERASE_BLOCK_SIZE
if op == 5: # block size
return self.ERASE_BLOCK_SIZE
if op == 6: # erase block
return 0
def test(bdev, vfs_class):
print("test", vfs_class)
# Initial format of block device.
vfs_class.mkfs(bdev)
# construction
print("mtime=True")
vfs = vfs_class(bdev, mtime=True)
# Create an empty file, should have a timestamp.
vfs.open("test1", "wt").close()
# Wait 1 second so mtime will increase by at least 1.
utime.sleep(1)
# Create another empty file, should have a timestamp.
vfs.open("test2", "wt").close()
# Stat the files and check that test1 is older than test2.
stat1 = vfs.stat("test1")
stat2 = vfs.stat("test2")
print(stat1[8] != 0, stat2[8] != 0)
print(stat1[8] < stat2[8])
# Wait 1 second so mtime will increase by at least 1.
utime.sleep(1)
# Open test1 for reading and ensure mtime did not change.
vfs.open("test1", "rt").close()
print(vfs.stat("test1") == stat1)
# Open test1 for writing and ensure mtime increased from the previous value.
vfs.open("test1", "wt").close()
stat1_old = stat1
stat1 = vfs.stat("test1")
print(stat1_old[8] < stat1[8])
# Unmount.
vfs.umount()
# Check that remounting with mtime=False can read the timestamps.
print("mtime=False")
vfs = vfs_class(bdev, mtime=False)
print(vfs.stat("test1") == stat1)
print(vfs.stat("test2") == stat2)
f = vfs.open("test1", "wt")
f.close()
print(vfs.stat("test1") == stat1)
vfs.umount()
# Check that remounting with mtime=True still has the timestamps.
print("mtime=True")
vfs = vfs_class(bdev, mtime=True)
print(vfs.stat("test1") == stat1)
print(vfs.stat("test2") == stat2)
vfs.umount()
bdev = RAMBlockDevice(30)
test(bdev, uos.VfsLfs2)