# Friendly Telegram (telegram userbot)
# Copyright (C) 2018-2019 The Authors
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU Affero General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU Affero General Public License for more details.
# You should have received a copy of the GNU Affero General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
import json
import asyncio
class NotifyingFuture(asyncio.Future):
def __init__(self, *args, **kwargs):
self.__to_notify_on_await = kwargs.pop("on_await", None)
super().__init__(*args, **kwargs)
def __await__(self):
if callable(self.__to_notify_on_await):
self.__to_notify_on_await()
return super().__await__()
# Not thread safe, use the event loop!
class Database(dict):
def __init__(self, backend, noop=False):
super().__init__()
self._noop = noop or backend is None
self._backend = backend
self._pending = None
self._loading = True
self._waiter = asyncio.Event()
self._sync_future = None
# We use a future because we need await-ability and we will be delaying by 10s, but
# because we are gonna frequently be changing the data, we want to avoid floodwait
# and to do that we will discard most requests. However, attempting to await any request
# should return a future corresponding to the next time that we flush the database.
# To achieve this, we have one future stored here (the next time we flush the db) and we
# always return that from set(). However, if someone decides to await set() much later
# than when they called set(), it will already be finished. Luckily, we return a future,
# not a reference to _sync_future, so it will be the correct future, and set_result will
# not already have been called. Simple, right?
def __repr__(self):
return object.__repr__(self)
async def init(self):
if self._noop:
self._loading = False
self._waiter.set()
return
await self._backend.init(self.reload)
db = await self._backend.do_download()
if db is not None:
try:
self.update(**json.loads(db))
except Exception:
# Don't worry if its corrupted. Just set it to {} and let it be fixed on next upload
pass
self._loading = False
self._waiter.set()
def save(self):
if self._pending is not None and not self._pending.cancelled():
self._pending.cancel()
if self._sync_future is None or self._sync_future.done():
self._sync_future = NotifyingFuture(on_await=self._cancel_then_set)
self._pending = asyncio.ensure_future(_wait_then_do(10, self._set)) # Delay database ops by 10s
return self._sync_future
def get(self, owner, key, default=None):
try:
return self[owner][key]
except KeyError:
return default
def set(self, owner, key, value):
super().setdefault(owner, {})[key] = value
return self.save()
def _cancel_then_set(self):
if self._pending is not None and not self._pending.cancelled():
self._pending.cancel()
self._pending = asyncio.ensure_future(self._set())
# Restart the task, but without the delay, because someone is waiting for us
async def _set(self):
if self._noop:
self._sync_future.set_result(True)
return
if self._loading:
await self._waiter.wait()
try:
await self._backend.do_upload(json.dumps(self))
except Exception as e:
self._sync_future.set_exception(e)
self._sync_future.set_result(True)
async def reload(self, event):
if self._noop:
return
try:
self._waiter.clear()
self._loading = True
if self._pending is not None:
self._pending.cancel()
db = await self._backend.do_download()
self.clear()
self.update(**json.loads(db))
finally:
self._loading = False
self._waiter.set()
async def store_asset(self, message):
return await self._backend.store_asset(message)
async def fetch_asset(self, message):
return await self._backend.fetch_asset(message)
async def _wait_then_do(time, task, *args, **kwargs):
await asyncio.sleep(time)
return await task(*args, **kwargs)
