The vstr argument to the calls to vstr_add_len are dynamically allocated
(ie fixed_buf=false) and so vstr_add_len will never return NULL. So
there's no need to check for it. Any out-of-memory errors are raised by
the call to m_renew in vstr_ensure_extra.
The aim of this patch is to rewrite the functions that create exception
instances (mp_obj_exception_make_new and mp_obj_new_exception_msg_varg) so
that they do not call any functions that may raise an exception. Otherwise
it's possible to create infinite recursion with an exception being raised
while trying to create an exception object.
The two main things that are done to accomplish this are:
1. Change mp_obj_new_exception_msg_varg to just format the string, then
call mp_obj_exception_make_new to actually create the exception object.
2. In mp_obj_exception_make_new and mp_obj_new_exception_msg_varg try to
allocate all memory first using functions that don't raise exceptions
If any of the memory allocations fail (return NULL) then degrade
gracefully by trying other options for memory allocation, eg using the
emergency exception buffer.
3. Use a custom printer backend to conservatively format strings: if it
can't allocate memory then it just truncates the string.
As part of this rewrite, raising an exception without a message, like
KeyError(123), will now use the emergency buffer to store the arg and
traceback data if there is no heap memory available.
Memory use with this patch is unchanged. Code size is increased by:
minimal x86: +124
unix x64: +72
unix nanbox: +96
This allows user classes to implement __abs__ special method, and saves
code size (104 bytes for x86_64), even though during refactor, an issue
was fixed and few optimizations were made:
* abs() of minimum (negative) small int value is calculated properly.
* objint_longlong and objint_mpz avoid allocating new object is the
argument is already non-negative.
Prior to this patch calling pyb.Timer(id) would always create a new timer
instance, even if there was an existing one. This patch fixes this
behaviour to match other peripherals, like UART, such that constructing a
timer with just the id will retrieve any existing instances.
The patch also refactors the way timers are validated on construction to
simplify and reduce code size.
If, for class X, X.__add__(Y) doesn't exist (or returns NotImplemented),
try Y.__radd__(X) instead.
This patch could be simpler, but requires undoing operand swap and
operation switch to get non-confusing error message in case __radd__
Previous to this patch the i2c.scan() method would do up to 100 probes per
I2C address, to detect the devices on the bus. This repeated probing was a
relic from when the code was copied from the accelerometer initialisation,
which requires to do repeated probes while waiting for the accelerometer
chip to turn on.
But I2C devices shouldn't need more than 1 probe to detect their presence,
and the generic software I2C implementation uses 1 probe successfully. So
this patch changes the implementation to use 1 probe per address, which
significantly speeds up the scan operation.
Originally, there were grouped in blocks of 5, to make it easier e.g.
to assess and numeric code of each. But now it makes more sense to
group it by semantics/properties, and then split in chunks still,
which usually leads to chunks of ~6 ops.
It starts a dichotomy of mp_binary_op_t values which can't appear in the
bytecode. Another reason to move it is to VALUES of OP_* and OP_INPLACE_*
nicely adjacent. This also will be needed for OP_REVERSE_*, to be soon
With MBEDTLS_DEBUG_C disabled the function mbedtls_debug_set_threshold()
doesn't exist. There's also no need to call mbedtls_ssl_conf_dbg() so a
few bytes can be saved on disabling that and not needing the mbedtls_debug
This patch adds a function utf8_check() to check for a valid UTF-8 encoded
string, and calls it when constructing a str from raw bytes. The feature
is selectable at compile time via MICROPY_PY_BUILTINS_STR_UNICODE_CHECK and
is enabled if unicode is enabled. It costs about 110 bytes on Thumb-2, 150
bytes on Xtensa and 170 bytes on x86-64.