Adds horizontal scrolling. Right now, I'm just leaving the margins
created by the scrolling as they were -- so they will repeat the
edge of the framebuf. This is fast, and the user can always fill
the margins themselves.
There was a bug in `framebuf1_fill` function, that makes it leave a few
lines unfilled at the bottom if the height is not divisible by 8.
A similar bug is fixed in the scroll method.
The idea is that all ports can use these helper methods and only need to
provide initialisation of the SPI bus, as well as a single transfer
function. The coding pattern follows the stream protocol and helper
methods.
This is an object-oriented approach, where uos is only a proxy for the
methods on the vfs object. Some internals had to be exposed (the STATIC
keyword removed) for this to work.
Fixes#2338.
In `btree_seq()`, when `__bt_seq()` gets called with invalid
`flags` argument it will return `RET_ERROR` and it won't
initialize `val`. If field `data` of uninitialized `val`
is passed to `mp_obj_new_bytes()` it causes a segfault.
This goes bit against websocket nature (message-based communication),
as it ignores boundaries bertween messages, but may be very practical
to do simple things with websockets.
In the sense that while GET_FILE transfers its data, REPL still works.
This is done by requiring client to send 1-byte block before WebREPL
server transfers next block of data.
Storing a chain of pbuf was an original design of @pfalcon's lwIP socket
module. The problem with storing just one, like modlwip does is that
"peer closed connection" notification is completely asynchronous and out of
band. So, there may be following sequence of actions:
1. pbuf #1 arrives, and stored in a socket.
2. pbuf #2 arrives, and rejected, which causes lwIP to put it into a
queue to re-deliver later.
3. "Peer closed connection" is signaled, and socket is set at such status.
4. pbuf #1 is processed.
5. There's no stored pbufs in teh socket, and socket status is "peer closed
connection", so EOF is returned to a client.
6. pbuf #2 gets redelivered.
Apparently, there's no easy workaround for this, except to queue all
incoming pbufs in a socket. This may lead to increased memory pressure,
as number of pending packets would be regulated only by TCP/IP flow
control, whereas with previous setup lwIP had a global overlook of number
packets waiting for redelivery and could regulate them centrally.
Allows to translate C-level pin API to Python-level pin API. In other
words, allows to implement a pin class and Python which will be usable
for efficient C-coded algorithms, like bitbanging SPI/I2C, time_pulse,
etc.
