The callback class can now accept generalized function-objects:
class Thing {
public:
int value;
void operator()() {
printf("hi! %d\n", value);
}
};
Callback<void()> cb(Thing(2));
However, with the intention of avoiding implicit dynamic-memory
allocations, the Callback class is limited to a single word of storage.
Exceeding this size will eliminate the function-object type from the
overload set and fail to compile.
Effort was invested to make this situation very clear to the user. Here
is an example error message with noise removed:
[ERROR] ./main.cpp: In function 'int main()':
./mbed-os/hal/api/Ticker.h:101:10: note:
no known conversion for argument 1 from 'BigFunc' to 'mbed::Callback<void()>'
The real benefit of this change is the ability for users to hook into
the attributes of the Callback class. This mostly allows lifetime
management of the function-objects from third-party libraries (such as
the Event class from mbed-events).
Note: The convenient `callback` function may become ambiguous if
provided with a type that defines multiple incompatible `operator()`
member functions.
This allows additional attributes to be attached to the internally
generated type such as move and destructor operations with no increase
in RAM footprint.
The current overloads can't take advantage of this, but it does open
the possibility for more powerful overloads that can provide these
additional attributes.
Changes to mbed-os memory consumption:
.text .data .bss
before 57887 2292 7692
after 57842 2292 7691
Before:
Callback<void()> a = callback(obj, member)
Callback<void()> b = callback(context, function)
After:
Callback<void()> a = callback(obj, member)
Callback<void()> b = callback(function, context)
This ordering is more intuitive based on feedback from users. This order
was initially considered but proved problematic when integrated with
other variable arguments in attach functions.
With `callback` as a separate convenience function, this style
no longer presents a problem.
- Add support of cortex-M7 for cthunk.
- Change the cthunk trampoline implementation to safer and quicker
solutions:
* thumb2, the behaviour was undefined. new implementation use now 2
instructions
* thumb, The new implementation use 3 instructions instead of 6.
One limitation of C++ is that implicit casts do not occur when
matching template overloads, as a consequence the callback's
argument type requires a strict match.
Unfortunately, the prevents the previously common pattern of using
void pointers as function arguments, causing unnecessary problems
for users porting code.
Thing *t;
void doit(void *p) { blablabla }
Callback<void()> cb(t, doit);
To avoid this, explicit overloads on void pointers were added. This
avoids a template expansion, and allows the implicit cast to occur
as the user would expect.
- Marked `call` and `operator()` functions as const
- Moved to static_cast for internal function pointer to avoid losing
compiler checked const-safety
- Added test for `operator=` with non-callback types
- Moved from zero-cast to value-initializer when callback is null
- Added `operator==` and `operator!=`
- Removed special handling of null callback
- Replicated doxygen to all overloads
- Added correct nops where uninitialized callbacks are called
- Added assertion for null callback
- Removed copy-constructor from callback constructor
This commit adds a dynamic memory tracer that calls a callback whenever
one of the basic memory allocation functions (malloc, realloc, calloc,
free) is called. The operation of the tracer is guarded by the
'MBED_MEM_TRACING_ENABLED` macro.
Infinite recursion during tracing is guarded by using atomic
increment/decrement primitives on the `trace_level` variable.
Thanks to @c1728p9 and @heky for their help and suggestions.
Additionally, the following changes were don to avoid combinatorial
explosion in function overloads as a result of adding cv-qualifiers:
- Added convenience function for inferred type
- Deprecated callback overloads qhere cv-qualifiers are not scalable
Supported overloads:
callback(void (*f)(A...));
callback(const Callback<R(A...)> &);
callback(T *t, void (*f)(T*, A...));
callback(const T *t, void (*f)(const T*, A...));
callback(volatile T *t, void (*f)(volatile T*, A...));
callback(const volatile T *t, void (*f)(const volatile T*, A...));
callback(T *t, void (T::*f)(A...));
callback(const T *t, void (T::*f)(A...) const);
callback(volatile T *t, void (T::*f)(A...) volatile);
callback(const volatile T *t, void (T::*f)(A...) const volatile);
Keep track of the current size allocated, maximum size allocated,
number of allocations, failed allocations and total size allocated for
both GCC and ARM. Report the maximum size allocated at the end of
testing.
Also, add a test to verify heap metrics are working as expected.
Check to see if ptr is NULL after acquiring the singleton lock to
prevent initialization race conditions. Also explicitly call the
constructor for type T.
From the discussion on issue #2068:
Functions marked deprecated in the mbed library should notate when
the deprecation was started to allow efficient removal once a set
amount of time has expired.
Added the following macro:
MBED_DEPRECATED_SINCE("version", "message string")
Example usage:
MBED_DEPRECATED_SINCE("v5.1", "don't foo any more, bar instead")
void foo(int arg);
Adopted in existing deprecations:
- FunctionPointer
- RtosTimer
- Thread
Currently this uses the same mechanism used by the rtos to conditionally
include the network-socket API. Perhaps this should be builtin to the
config system?
Note: this does require that the bug-compatible inclusion of mbed.h
be removed to avoid include-order issues.
per @sg-
Before, the following results in a compilation error:
const struct Object *obj;
void obj_doit(const Object *obj);
Callback<void()> cb(obj, obj_doit);
This is especially noticable when migrating from the old Thread
constructor, which previously _required_ const.
Short term fix for all cv qualifiers through a C cast:
void *_obj = (void*)obj;
FunctionPointer/FunctionPointerArg0/FunctionPointerArg1 has been
replaced by the more flexible Callback template class.
For the motivation behind adopting the Callback class:
https://github.com/mbedmicro/mbed/pull/1783
Create the wrapper class SingletonPtr. This provides a safe way to
declare and use singletons. This class allows both the lazy
initialization of a singleton, and allows the singleton to be
garbage collected by the linker if it is never referenced.
This patch also updates the HAL to use SingletonPtr when declaring
singleton mutexes.
and update the using functions accordingly.
Usage:
bool interrupts_enabled = are_interrupts_enabled()
Remove superfluos shift in are_interrupts_enabled().
than an integer. This removes the need for all users to mask the returned
value with 0x1 to determine interrupt status.
Expose this function externally to allow other users to check interrupt
status in a manner which will work for both cortex-A and cortex-M .
Usage:
bool disabled = get_interrupts_disabled();
Add a virtual destructor to classes which have a virtual lock and
unlock. Remove the virtual qualifier from functions in
InterruptManager since this class cannot be extended.
Sam Grove
Christopher Haster
Vincent Coubard
Martin Kojtal
svastm
Russ Butler
Bogdan Marinescu
Bartek Szatkowski
Russ Butler
Martin Kojtal
neilt6
Anna Bridge