cista-storage/cista/fileio.py

96 lines
2.8 KiB
Python
Executable File

import asyncio
import os
from cista import config
from cista.util import filename
from cista.util.asynclink import AsyncLink
from cista.util.lrucache import LRUCache
def fuid(stat) -> str:
"""Unique file ID. Stays the same on renames and modification."""
return config.derived_secret("filekey-inode", stat.st_dev, stat.st_ino).hex()
class File:
def __init__(self, filename):
self.path = config.config.path / filename
self.fd = None
self.writable = False
def open_ro(self):
self.close()
self.fd = os.open(self.path, os.O_RDONLY)
def open_rw(self):
self.close()
self.path.parent.mkdir(parents=True, exist_ok=True)
self.fd = os.open(self.path, os.O_RDWR | os.O_CREAT)
self.writable = True
def write(self, pos, buffer, *, file_size=None):
if not self.writable:
# Create/open file
self.open_rw()
assert self.fd is not None
if file_size is not None:
os.ftruncate(self.fd, file_size)
os.lseek(self.fd, pos, os.SEEK_SET)
os.write(self.fd, buffer)
def __getitem__(self, slice):
if self.fd is None:
self.open_ro()
assert self.fd is not None
os.lseek(self.fd, slice.start, os.SEEK_SET)
size = slice.stop - slice.start
data = os.read(self.fd, size)
if len(data) < size:
raise EOFError("Error reading requested range")
return data
def close(self):
if self.fd is not None:
os.close(self.fd)
self.fd = self.writable = None
def __del__(self):
self.close()
class FileServer:
async def start(self):
self.alink = AsyncLink()
self.worker = asyncio.get_event_loop().run_in_executor(
None, self.worker_thread, self.alink.to_sync
)
self.cache = LRUCache(File, capacity=10, maxage=5.0)
async def stop(self):
await self.alink.stop()
await self.worker
def worker_thread(self, slink):
try:
for req in slink:
with req as (command, *args):
if command == "upload":
req.set_result(self.upload(*args))
elif command == "download":
req.set_result(self.download(*args))
else:
raise NotImplementedError(f"Unhandled {command=} {args}")
finally:
self.cache.close()
def upload(self, name, pos, data, file_size):
name = filename.sanitize(name)
f = self.cache[name]
f.write(pos, data, file_size=file_size)
return len(data)
def download(self, name, start, end):
name = filename.sanitize(name)
f = self.cache[name]
return f[start:end]