GLIB has recently started to officially support the gcc cleanup
attribute in its public API, hence let's do the same for our APIs.
With this patch we'll define an xyz_unrefp() call for each public
xyz_unref() call, to make it easy to use inside a
__attribute__((cleanup())) expression. Then, all code is ported over to
make use of this.
The new calls are also documented in the man pages, with examples how to
use them (well, I only added docs where the _unref() call itself already
had docs, and the examples, only cover sd_bus_unrefp() and
sd_event_unrefp()).
This also renames sd_lldp_free() to sd_lldp_unref(), since that's how we
tend to call our destructors these days.
Note that this defines no public macro that wraps gcc's attribute and
makes it easier to use. While I think it's our duty in the library to
make our stuff easy to use, I figure it's not our duty to make gcc's own
features easy to use on its own. Most likely, client code which wants to
make use of this should define its own:
#define _cleanup_(function) __attribute__((cleanup(function)))
Or similar, to make the gcc feature easier to use.
Making this logic public has the benefit that we can remove three header
files whose only purpose was to define these functions internally.
See #2008.
There are more than enough calls doing string manipulations to deserve
its own files, hence do something about it.
This patch also sorts the #include blocks of all files that needed to be
updated, according to the sorting suggestions from CODING_STYLE. Since
pretty much every file needs our string manipulation functions this
effectively means that most files have sorted #include blocks now.
Also touches a few unrelated include files.
Prior to commit c32eb440ba, libudev's
function udev_enumerate_scan_devices() had behaved differently. If
parent match was added with udev_enumerate_add_match_parent(),
udev_enumerate_scan_devices() did not return error if some child devices
had no subsystem symlink in sysfs. An example of such devices is USB
endpoints /sys/bus/usb/devices/*/ep_*. If there was a parent match
against USB device, old implementation of udev_enumerate_scan_devices()
did not treat ep_* device directories without subsystem symlink as error
and just ignored them, but new implementation returns -ENOENT (also
ignoring these devices) though correctly enumerates all other matching
devices.
To compare, you could look at 96df036fe3,
in src/libudev/libudev-enumerate.c, function parent_add_child():
if (!match_subsystem(enumerate, udev_device_get_subsystem(dev)))
goto nomatch;
udev_device_get_subsystem() was returning NULL, match_subsystem() was
returning false, and USB endpoint device was ignored.
New parent_add_child() from src/libsystemd/sd-device/device-enumerator.c
checks return value of sd_device_get_subsystem() and fails if subsystem
was not found. Absence of subsystem symlink should not be really treated
as error because all enumerations of children of USB devices will fail
with -ENOENT. This new behavior also breaks system-config-printer.
So restore old behavior and treat absence of subsystem symlink as no
match.
Boolean arithmetic is great, use it!
if (a && !b)
return 1;
if (!a && b)
return -1,
is equivalent to
if (a != b)
return a - b;
Furthermore:
r = false;
if (condition)
r = true;
is equivalent to:
r = condition;
sd_device_new_from_* now returns -ENODEV when the device does not exist, and the enumerator
silently drops these errors as missing devices is exepected.
It is still possible to include uninitialized ones, but now that is opt-in. In most
cases people only want initialized devices. Exception is if you want to work without
udev running.
Suggested by David Herrmann.
