c6c7ab2b44
Event lib support as it has been isn't scaling well, at the low level libevent and libev headers have a namespace conflict so they can't both be built into the same image, and at the distro level, binding all the event libs to libwebsockets.so makes a bloaty situation for packaging, lws will drag in all the event libs every time. This patch implements the plan discussed here https://github.com/warmcat/libwebsockets/issues/1980 and refactors the event lib support so they are built into isolated plugins and bound at runtime according to what the application says it wants to use. The event lib plugins can be packaged individually so that only the needed sets of support are installed (perhaps none of them if the user code is OK with the default poll() loop). And dependent user code can mark the specific event loop plugin package as required so pieces are added as needed. The eventlib-foreign example is also refactored to build the selected lib support isolated. A readme is added detailing the changes and how to use them. https://libwebsockets.org/git/libwebsockets/tree/READMEs/README.event-libs.md |
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| .. | ||
| CMakeLists.txt | ||
| dbus.c | ||
| private-lib-roles-dbus.h | ||
| README.md | ||
DBUS Role Support
DBUS-related distro packages
Fedora: dbus-devel Debian / Ubuntu: libdbus-1-dev
Enabling for build at cmake
Fedora example:
$ cmake .. -DLWS_ROLE_DBUS=1 -DLWS_DBUS_INCLUDE2="/usr/lib64/dbus-1.0/include"
Ubuntu example:
$ cmake .. -DLWS_ROLE_DBUS=1 -DLWS_DBUS_INCLUDE2="/usr/lib/x86_64-linux-gnu/dbus-1.0/include"
Dbus requires two include paths, which you can force by setting LWS_DBUS_INCLUDE1
and LWS_DBUS_INCLUDE2. Although INCLUDE1 is usually guessable, both can be
forced to allow cross-build.
If these are not forced, then lws cmake will try to check some popular places,
for LWS_DBUS_INCLUDE1, on both Fedora and Debian / Ubuntu, this is
/usr/include/dbus-1.0... if the directory exists, it is used.
For LWS_DBUS_INCLUDE2, it is the arch-specific dbus header which may be
packaged separately than the main dbus headers. On Fedora, this is in
/usr/lib[64]/dbus-1.0/include... if not given externally, lws cmake will
try /usr/lib64/dbus-1.0/include. On Debian / Ubuntu, the package installs
it in an arch-specific dir like /usr/lib/x86_64-linux-gnu/dbus-1.0/include,
you should force the path.
The library path is usually [lib] "dbus-1", but this can also be forced if
you want to build cross or use a special build, via LWS_DBUS_LIB.
Building against local dbus build
If you built your own local dbus and installed it in /usr/local, then this is the incantation to direct lws to use the local version of dbus:
cmake .. -DLWS_ROLE_DBUS=1 -DLWS_DBUS_INCLUDE1="/usr/local/include/dbus-1.0" -DLWS_DBUS_INCLUDE2="/usr/local/lib/dbus-1.0/include" -DLWS_DBUS_LIB="/usr/local/lib/libdbus-1.so"
You'll also need to give the loader a helping hand to do what you want if
there's a perfectly good dbus lib already in /usr/lib[64] using LD_PRELOAD
like this
LD_PRELOAD=/usr/local/lib/libdbus-1.so.3.24.0 myapp
Lws dbus api exports
Because of the irregular situation with libdbus includes, if lws exports the
dbus helpers, which use dbus types, as usual from #include <libwebsockets.h>
then if lws was compiled with dbus role support it forces all users to take
care about the dbus include path mess whether they use dbus themselves or not.
For that reason, if you need access to the lws dbus apis, you must explicitly include them by
#include <libwebsockets/lws-dbus.h>
This includes <dbus/dbus.h> and so requires the include paths set up. But
otherwise non-dbus users that don't include libwebsockets/lws-dbus.h don't
have to care about it.
DBUS and valgrind
https://cgit.freedesktop.org/dbus/dbus/tree/README.valgrind
- One-time 6KiB "Still reachable" caused by abstract unix domain socket + libc
getgrouplist()via nss... bug since 2004(!)