MicroPython code may rely on the return value of sys.stdout.buffer.write()
to reflect the number of bytes actually written. While in most scenarios a
write() operation is successful, there are cases where it fails, leading to
data loss. This problem arises because, currently, write() merely returns
the number of bytes it was supposed to write, without indication of
failure.
One scenario where write() might fail, is where USB is used and the
receiving end doesn't read quickly enough to empty the receive buffer. In
that case, write() on the MicroPython side can timeout, resulting in the
loss of data without any indication, a behavior observed notably in
communication between a Pi Pico as a client and a Linux host using the ACM
driver.
A complex issue arises with mp_hal_stdout_tx_strn() when it involves
multiple outputs, such as USB, dupterm and hardware UART. The challenge is
in handling cases where writing to one output is successful, but another
fails, either fully or partially. This patch implements the following
solution:
mp_hal_stdout_tx_strn() attempts to write len bytes to all of the possible
destinations for that data, and returns the minimum successful write
length.
The implementation of this is complicated by several factors:
- multiple outputs may be enabled or disabled at compiled time
- multiple outputs may be enabled or disabled at runtime
- mp_os_dupterm_tx_strn() is one such output, optionally containing
multiple additional outputs
- each of these outputs may or may not be able to report success
- each of these outputs may or may not be able to report partial writes
As a result, there's no single strategy that fits all ports, necessitating
unique logic for each instance of mp_hal_stdout_tx_strn().
Note that addressing sys.stdout.write() is more complex due to its data
modification process ("cooked" output), and it remains unchanged in this
patch. Developers who are concerned about accurate return values from
write operations should use sys.stdout.buffer.write().
This patch might disrupt some existing code, but it's also expected to
resolve issues, considering that the peculiar return value behavior of
sys.stdout.buffer.write() is not well-documented and likely not widely
known. Therefore, it's improbable that much existing code relies on the
previous behavior.
Signed-off-by: Maarten van der Schrieck <maarten@thingsconnected.nl>
If a non-string buffer was passed to execfile, then it would be passed
as a non-null-terminated char* to mp_lexer_new_from_file.
This changes mp_lexer_new_from_file to take a qstr instead (as in almost
all cases a qstr will be created from this input anyway to set the
`__file__` attribute on the module).
This now makes execfile require a string (not generic buffer) argument,
which is probably a good fix to make anyway.
Fixes issue #12522.
This work was funded through GitHub Sponsors.
Signed-off-by: Jim Mussared <jim.mussared@gmail.com>
When the "typeof window" check is run within a web worker the window is
undefined, causing an error because "require" is only defined in a Node
environment. Change the logic to reflect the true intentions of when this
code should run, ie in Node only.
Signed-off-by: Damien George <damien@micropython.org>
This fixes a bug where `gc.collect()` would crash due to
emscripten_scan_stack being called synchronously within mp_js_do_str. The
fix is to make mp_js_do_str asynchronous.
Fixes#10692.
Signed-off-by: Eli Bierman <eli@elib.dev>
Based on extmod/utime_mphal.c, with:
- a globals dict added
- time.localtime wrapper added
- time.time wrapper added
- time.time_ns function added
New configuration options are added for this module:
- MICROPY_PY_UTIME (enabled at basic features level)
- MICROPY_PY_UTIME_GMTIME_LOCALTIME_MKTIME
- MICROPY_PY_UTIME_TIME_TIME_NS
Signed-off-by: Damien George <damien@micropython.org>
This changes the CustomEvent for stdout to use the existing `detail`
property of CustomEvent instead of adding a `data` property.
Signed-off-by: David Lechner <david@pybricks.com>
Emscripten strongly advises the use of optimisation when compiling with
ASYNCIFY enabled. Testing the difference betwen O3 and Os for various
configurations gives:
flags firmware.wasm micropython.js perf
-O3 -s ASYNCIFY 1342003 212845 0 (baseline)
-O3 -s ASYNCIFY -s WASM=0 - 7064750 -30%
-O3 367131 196569 +140%
-O3 -s WASM=0 - 2818260 +30%
-Os -s ASYNCIFY 1135450 213064 +40%
-Os -s ASYNCIFY -s WASM=0 - 6239768 -30%
-Os 295028 196569 +180%
-Os -s WASM=0 - 2271358 +30%
The first row is prior to this commit. The second and third columns show
firmware size (add them to get the total size). The fourth column shows
the approximate change in performance compared to the baseline. The
performance was measured using run-perfbench.py and the error was large, up
to 20%, although general trends in the change in performance could still be
seen.
In summary, using using Os instead of O3 makes it a little bit faster in
all cases, and smaller output (wasm/js) in all cases.
Signed-off-by: Damien George <damien@micropython.org>
This simplifies the config file. This is not a no-op, it does enable a few
new features to bring the port in line with this config level.
Signed-off-by: Damien George <damien@micropython.org>
Maarten van der Schrieck