libwebsockets/lib/event-libs/libev/CMakeLists.txt
Andy Green c6c7ab2b44 event libs: default to building as dynamically loaded plugins
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
2020-08-31 16:51:37 +01:00

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2.9 KiB
CMake

#
# libwebsockets - small server side websockets and web server implementation
#
# Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com>
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to
# deal in the Software without restriction, including without limitation the
# rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
# sell copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in
# all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
# FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
# IN THE SOFTWARE.
#
# The strategy is to only export to PARENT_SCOPE
#
# - changes to LIB_LIST
# - includes via include_directories
#
# and keep everything else private
include_directories(.)
set(LWS_LIBEV_LIBRARIES CACHE PATH "Path to the libev library")
set(LWS_LIBEV_INCLUDE_DIRS CACHE PATH "Path to the libev include directory")
if (NOT LIBEV_FOUND)
find_path(LIBEV_INCLUDE_DIRS NAMES ev.h)
find_library(LIBEV_LIBRARIES NAMES ev)
endif()
message("libev include dir: ${LIBEV_INCLUDE_DIRS}")
message("libev libraries: ${LIBEV_LIBRARIES}")
include_directories("${LIBEV_INCLUDE_DIRS}")
if ("${LWS_LIBEV_LIBRARIES}" STREQUAL "" OR "${LWS_LIBEV_INCLUDE_DIRS}" STREQUAL "")
else()
set(LIBEV_LIBRARIES ${LWS_LIBEV_LIBRARIES})
set(LIBEV_INCLUDE_DIRS ${LWS_LIBEV_INCLUDE_DIRS})
endif()
if (LWS_WITH_EVLIB_PLUGINS)
create_evlib_plugin(
evlib_ev
libev.c
private-lib-event-libs-libev.h
${LIBEV_LIBRARIES})
else()
list(APPEND LIB_LIST ${LIBEV_LIBRARIES})
list(APPEND SOURCES
event-libs/libev/libev.c)
# see README.build.md for discussion of why of the supported event libs,
# only libev cannot cope with -Werror
set_source_files_properties(event-libs/libev/libev.c
PROPERTIES COMPILE_FLAGS "-Wno-error" )
endif()
set(CMAKE_REQUIRED_LIBRARIES ${LIB_LIST})
CHECK_C_SOURCE_COMPILES(
"#include <ev.h>
int main(int argc, char **argv) { return EVBACKEND_LINUXAIO; }
" LWS_HAVE_EVBACKEND_LINUXAIO)
CHECK_C_SOURCE_COMPILES(
"#include <ev.h>
int main(int argc, char **argv) { return EVBACKEND_IOURING; }
" LWS_HAVE_EVBACKEND_IOURING)
#
# Keep explicit parent scope exports at end
#
exports_to_parent_scope()
set(LWS_HAVE_EVBACKEND_LINUXAIO ${LWS_HAVE_EVBACKEND_LINUXAIO} PARENT_SCOPE)
set(LWS_HAVE_EVBACKEND_IOURING ${LWS_HAVE_EVBACKEND_IOURING} PARENT_SCOPE)