This has been an attempt to extend existing FileHandle to behave like POSIX
file descriptor for input/output resources/devices too.
This will now provide an abstract indicator/handle any arbitrary file or device
type resource. May be in future, sockets too.
In order to correctly detect availability of read/write a FileHandle, we needed
a select or poll mechanisms. We opted for poll as POSIX defines in
http://pubs.opengroup.org/onlinepubs/009695399/functions/poll.html Currently,
mbed::poll() just spins and scans filehandles looking for any events we are
interested in. In future, his spinning behaviour will be replaced with
condition variables.
In retarget.cpp we have introduced an mbed::fdopen() function which is
equivalent to C fdopen(). It attaches a std stream to our FileHandle stream.
newlib-nano somehow does not seem to call isatty() so retarget doesn't work for
device type file handles. We handle this by checking ourselves in
mbed::fdopen() if we wish to attach our stream to std stream. We also turn off
buffering by C library as our stuff will be buffered already.
sigio() is also provided, matching the API of the Socket class, with a view to
future unification. As well as unblocking poll(), _poll_change calls the user
sigio callback if an event happens, i.e., when FileHandle becomes
readable/writable.
* Don't set errno when calls are successful (will slightly alleviate the problem
of errno not being thread-safe yet).
* Transfer errors returned from size() and seek() into errno.
* Fix isatty() - could never return 1 from a FileHandle.
* Use more appropriate errors than EBADF in some places (eg ENOENT for non-existant path).
As identified by @hasnainvirk, @kjbracey-arm, the FileHandle and
FileBase serve two separate functions and their integration is
limiting for certain use cases.
FileLike is actually the redundant class here, but the multiple
inheritance it provides is used as a hack by the retargeting code
to get at the FileHandle implementation bound to the FileBase name.
It may make more sense for the FileBase to inherit from FileHandle,
(with perhaps a different name), but rather than explore the
possibility, this will just restore the previous hierarchy.
- Fixing code formatting errors with astyle tool.
- Replaced use of TOOLCHAIN_xxx macros with compiler emitted macros.
- Added const to BlockDevice::get_xxx_size() member functions.
- Added documentation for FAT filesystem thread support.
- Added documentation for fat_filesystem_set_errno().
- Added documentation clarifying the reasons for errno/stat symbol definitions in retarget.h.
- Removed FAT filesystem from mbed 2 testing.
- Fixed FATMisc.h Copyright (c) 2016 year to 2017 as its a new file.
- Removed #ifndef NDEBUG from HeapBlockDevice.cpp.
- Removed unnecessary todo comment in retarget.cpp.
Hasnain Virk
Kevin Bracey
Bartek Szatkowski
Neil Thiessen
Christopher Haster
Simon Hughes