Move the macros to a single place and reduce the variations not based on
board, but based on
- The name of the entry-point function, specified by AP_MAIN;
- Whether it contains argc/argv arguments or not.
The goal here is that programs (vehicles and examples) don't need to
include all possible boards to define a main function. Further patches
will change the programs.
Instead of requiring every program to specify the HAL related modules,
let the build system do it (in practice everything we compiled depended
on HAL anyway). This allow including only the necessary files in the
compilation.
The switching between different AP_HAL was happening by giving different
definitions of AP_HAL_BOARD_DRIVER, and the programs would use it to
instantiate.
A program or library code would have to explicitly include (and depend)
on the concrete implementation of the HAL, even when using it only via
interface.
The proposed change move this dependency to be link time. There is a
AP_HAL::get_HAL() function that is used by the client code. Each
implementation of HAL provides its own definition of this function,
returning the appropriate concrete instance.
Since this replaces the job of AP_HAL_BOARD_DRIVER, the definition was
removed.
The static variables for PX4 and VRBRAIN were named differently to avoid
shadowing the extern symbol 'hal'.
Now instead of requiring the buffer to fill completely before we can
detect it is not draining, we use a time based mechanism to detect
when none of the first few bytes are transmitted after sitting in our
buffer a half second or more after flow control is enabled. This
huristic is reliable only for the first several chracters because we
believe that the radio must still have plenty of room in it's own
buffers at that time even if it is not able to transmit them to the
other radio yet. Note that the original algorithm made the same
assumption.
The new algorithm is especially helpful for cases where only keepalive
messages are transmitted before other packets can be requested by the
GCS. In this situation, the original code required almost 2 minutes
to disable flow control and allow communication with the GCS.
This commit changes the way libraries headers are included in source files:
- If the header is in the same directory the source belongs to, so the
notation '#include ""' is used with the path relative to the directory
containing the source.
- If the header is outside the directory containing the source, then we use
the notation '#include <>' with the path relative to libraries folder.
Some of the advantages of such approach:
- Only one search path for libraries headers.
- OSs like Windows may have a better lookup time.
The modification allows the read and write functions to be called by any thread but the calling thread must be the last one that called the begin() function.
Caio Marcelo de Oliveira Filho
Andrew Tridgell
Lucas De Marchi
Tom Pittenger
Brad Bosch
Gustavo Jose de Sousa
Julien BERAUD
Eugene Shamaev
Randy Mackay
Jonathan Challinger
Andrew Tridgell
Matthias Badaire