Mark WebServer, ListEntitiesIterator, DeferredUpdateEventSource, and
DeferredUpdateEventSourceList as final since none are subclassed.
This enables the compiler to devirtualize calls to the many virtual
overrides from Component, Controller, AsyncWebHandler, and
ComponentIterator.
Also remove the unnecessary virtual destructor from ListEntitiesIterator
since the class is now final and the base class (ComponentIterator) has
no virtual destructor.
Neither class is subclassed. Marking them final enables the compiler
to devirtualize calls to the Component overrides (loop, dump_config,
get_setup_priority, on_safe_shutdown).
All set_data_callback, set_part_complete_callback, onNotFound, and
onConnect methods were taking std::function/callback by value despite
every caller passing a lambda temporary. Change to rvalue reference
to eliminate unnecessary move+destroy overhead.
All subscribe_home_assistant_state, get_home_assistant_state, and
add_state_subscription_ methods were taking std::function by value
despite every caller passing a temporary or std::move()'d value.
Change to rvalue reference to eliminate unnecessary move+destroy
overhead at each forwarding layer.
Change set_timer_common_ to take std::function<void()>&& instead of
by value. This avoids materializing a std::function copy on the stack
at each call site — the caller just passes a pointer to the rvalue.
On BK7231N (Thumb-1), each forwarder (set_timeout, set_interval) was
118 bytes due to the inlined std::function move constructor + register
spilling. With rvalue reference, they shrink to 32 bytes each.
All 12 callers already pass rvalues (std::move or lambda temporaries),
so this is a purely mechanical change with no semantic difference.
BK7231N: forwarders 118 -> 32 bytes each, ~258 bytes saved total
ESP32: forwarders 46 -> 30 bytes each, ~20 bytes saved total
Change set_timer_common_ to take std::function<void()>&& instead of
by value. This avoids materializing a std::function copy on the stack
at each call site — the caller just passes a pointer to the rvalue.
On BK7231N (Thumb-1), each forwarder (set_timeout, set_interval) was
118 bytes due to the inlined std::function move constructor + register
spilling. With rvalue reference, they shrink to 32 bytes each.
All 12 callers already pass rvalues (std::move or lambda temporaries),
so this is a purely mechanical change with no semantic difference.
BK7231N: forwarders 118 -> 32 bytes each, ~258 bytes saved total
ESP32: forwarders 46 -> 30 bytes each, ~20 bytes saved total
On BK7231N (Thumb-1/Cortex-M0), GCC inlines ~unique_ptr<SchedulerItem>
(~30 bytes: null check + ~std::function + operator delete) at every
destruction site, while ESP32/ESP8266/RTL8720CF outline it into a single
shared helper. This causes significant flash bloat in scheduler functions.
Use a custom deleter (SchedulerItemDeleter) with its operator() defined
in the .cpp file, ensuring the compiler emits exactly one copy of the
destruction code. All destruction sites now generate a simple function
call instead of inlining the full body.
BK7231N savings (bytes):
- call(): 816 -> 670 (-146)
- process_to_add(): 390 -> 308 (-82)
- __adjust_heap: 430 -> 312 (-118)
- pop_raw_locked_(): 192 -> 140 (-52)
- cleanup_(): 130 -> 112 (-18)
- SchedulerItemDeleter: +32 (new, single copy)
- Net: ~384 bytes saved
ESP32/ESP8266/RTL8720CF are unaffected (already outline the destructor).
On BK7231N (Thumb-1/Cortex-M0), GCC inlines ~unique_ptr<SchedulerItem>
(~30 bytes: null check + ~std::function + operator delete) at every
destruction site, while ESP32/ESP8266/RTL8720CF outline it into a single
shared helper. This causes significant flash bloat in scheduler functions.
Use a custom deleter (SchedulerItemDeleter) with its operator() defined
in the .cpp file, ensuring the compiler emits exactly one copy of the
destruction code. All destruction sites now generate a simple function
call instead of inlining the full body.
BK7231N savings (bytes):
- call(): 816 -> 670 (-146)
- process_to_add(): 390 -> 308 (-82)
- __adjust_heap: 430 -> 312 (-118)
- pop_raw_locked_(): 192 -> 140 (-52)
- cleanup_(): 130 -> 112 (-18)
- SchedulerItemDeleter: +32 (new, single copy)
- Net: ~384 bytes saved
ESP32/ESP8266/RTL8720CF are unaffected (already outline the destructor).
The BK7231N Thumb-1 compiler inlines this function 3 times into
cancel_item_locked_, bloating it from ~140 B to 666 B. ESP32 and
RTL8720CF compilers already outline it, so this attribute only
affects BK7231N. Saves ~486 B of flash.
J. Nick Koston