circuitpython/tests/extmod/vfs_userfs.py
Damien George 60f5b941e0 extmod/vfs_reader: Fix mp_reader_new_file to open file in "rb" mode.
mp_reader_new_file() is used to read in files for importing, either .py or
.mpy files, for the lexer and persistent code loader respectively.  In both
cases the file should be opened in raw bytes mode: the lexer handles
unicode characters itself, and .mpy files contain 8-bit bytes by nature.

Before this commit importing was working correctly because, although the
file was opened in text mode, all native filesystem implementations (POSIX,
FAT, LFS) would access the file in raw bytes mode via mp_stream_rw()
calling mp_stream_p_t.read().  So it was only an issue for non-native
filesystems, such as those implemented in Python.  For Python-based
filesystem implementations, a call to mp_stream_rw() would go via IOBase
and then to readinto() at the Python level, and readinto() is only defined
on files opened in raw bytes mode.

Signed-off-by: Damien George <damien@micropython.org>
2020-08-12 23:40:50 +10:00

85 lines
1.8 KiB
Python

# test VFS functionality with a user-defined filesystem
# also tests parts of uio.IOBase implementation
import sys
try:
import uio
uio.IOBase
import uos
uos.mount
except (ImportError, AttributeError):
print("SKIP")
raise SystemExit
class UserFile(uio.IOBase):
def __init__(self, mode, data):
assert isinstance(data, bytes)
self.is_text = mode.find("b") == -1
self.data = data
self.pos = 0
def read(self):
if self.is_text:
return str(self.data, "utf8")
else:
return self.data
def readinto(self, buf):
assert not self.is_text
n = 0
while n < len(buf) and self.pos < len(self.data):
buf[n] = self.data[self.pos]
n += 1
self.pos += 1
return n
def ioctl(self, req, arg):
print("ioctl", req, arg)
return 0
class UserFS:
def __init__(self, files):
self.files = files
def mount(self, readonly, mksfs):
pass
def umount(self):
pass
def stat(self, path):
print("stat", path)
if path in self.files:
return (32768, 0, 0, 0, 0, 0, 0, 0, 0, 0)
raise OSError
def open(self, path, mode):
print("open", path, mode)
return UserFile(mode, self.files[path])
# create and mount a user filesystem
user_files = {
"/data.txt": b"some data in a text file",
"/usermod1.py": b"print('in usermod1')\nimport usermod2",
"/usermod2.py": b"print('in usermod2')",
}
uos.mount(UserFS(user_files), "/userfs")
# open and read a file
f = open("/userfs/data.txt")
print(f.read())
# import files from the user filesystem
sys.path.append("/userfs")
import usermod1
# unmount and undo path addition
uos.umount("/userfs")
sys.path.pop()