ZeroMQ: Use IMPORTED targets

- Adopt FindZeroMQ.cmake from cppzmq, and use its `libzmq` target
- Also use `cppzmq` target, if created

Author: ferdnyc

cmake/Modules/FindZeroMQ.cmake

@@ -0,0 +1,39 @@
+set(PKG_CONFIG_USE_CMAKE_PREFIX_PATH ON)
+find_package(PkgConfig)
+pkg_check_modules(PC_LIBZMQ QUIET libzmq)
+
+set(ZeroMQ_VERSION ${PC_LIBZMQ_VERSION})
+find_path(ZeroMQ_INCLUDE_DIR zmq.h PATHS ${PC_LIBZMQ_INCLUDE_DIRS} $ENV{ZMQDIR})
+
+find_library(ZeroMQ_LIBRARY NAMES libzmq.so libzmq.dylib libzmq.dll
+PATHS ${PC_LIBZMQ_LIBDIR} ${PC_LIBZMQ_LIBRARY_DIRS} $ENV{ZMQDIR})
+find_library(ZeroMQ_STATIC_LIBRARY NAMES libzmq-static.a libzmq.a libzmq.dll.a
+             PATHS ${PC_LIBZMQ_LIBDIR} ${PC_LIBZMQ_LIBRARY_DIRS} $ENV{ZMQDIR})
+
+if(ZeroMQ_LIBRARY OR ZeroMQ_STATIC_LIBRARY)
+    set(ZeroMQ_FOUND ON)
+endif()
+
+if (TARGET libzmq)
+    # avoid errors defining targets twice
+    return()
+endif()
+
+set(ZeroMQ_INCLUDE_DIRS ${ZeroMQ_INCLUDE_DIR})
+list(APPEND ZeroMQ_INCLUDE_DIRS ${PC_LIBZMQ_INCLUDE_DIRS})
+list(REMOVE_DUPLICATES ZeroMQ_INCLUDE_DIRS)
+
+add_library(libzmq SHARED IMPORTED)
+set_property(TARGET libzmq PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${ZeroMQ_INCLUDE_DIRS})
+set_property(TARGET libzmq PROPERTY IMPORTED_LOCATION ${ZeroMQ_LIBRARY})
+
+add_library(libzmq-static STATIC IMPORTED ${ZeroMQ_INCLUDE_DIRS})
+set_property(TARGET libzmq-static PROPERTY INTERFACE_INCLUDE_DIRECTORIES ${ZeroMQ_INCLUDE_DIRS})
+set_property(TARGET libzmq-static PROPERTY IMPORTED_LOCATION ${ZeroMQ_STATIC_LIBRARY})
+
+include(FindPackageHandleStandardArgs)
+find_package_handle_standard_args(ZeroMQ
+  REQUIRED_VARS
+    ZeroMQ_LIBRARY ZeroMQ_INCLUDE_DIRS
+  VERSION_VAR
+    ZeroMQ_VERSION)

src/CMakeLists.txt

@@ -138,19 +138,6 @@ IF (ENABLE_BLACKMAGIC)
 	ENDIF (BLACKMAGIC_FOUND)
 ENDIF (ENABLE_BLACKMAGIC)
 
-################### ZEROMQ #####################
-# Find ZeroMQ library (used for socket communication & logging)
-
-# Some platforms package the header-only cppzmq C++ bindings separately,
-# others (Ubuntu) bundle them in with libzmq itself
-find_package(cppzmq QUIET)
-find_package(ZMQ REQUIRED)
-
-# Include ZeroMQ headers (needed for compile)
-include_directories(${ZMQ_INCLUDE_DIRS})
-if (cppzmq_FOUND)
-    include_directories(${cppzmq_INCLUDE_DIRS})
-endif()
 
 ################### RESVG #####################
 # Find resvg library (used for rendering svg files)
@@ -291,14 +278,28 @@ endif()
 
 target_link_libraries(openshot PUBLIC OpenMP::OpenMP_CXX)
 
+################### ZEROMQ #####################
+# Find ZeroMQ library (used for socket communication & logging)
+find_package(ZeroMQ REQUIRED) # Creates libzmq target
+
+# Some platforms package the header-only cppzmq C++ bindings separately,
+# others (Ubuntu) bundle them in with libzmq itself
+find_package(cppzmq QUIET) # Creates cppzmq target
+
+# Include ZeroMQ headers (needed for compile)
+target_link_libraries(openshot PUBLIC libzmq)
+if (TARGET cppzmq)
+  target_link_libraries(openshot PUBLIC cppzmq)
+endif()
+
+
 ###############  LINK LIBRARY  #################
 SET ( REQUIRED_LIBRARIES
 		${LIBOPENSHOT_AUDIO_LIBRARIES}
 		${FF_LIBRARIES}
 		${QT_LIBRARIES}
 		${PROFILER}
 		${JSONCPP_LIBRARY}
-		${ZMQ_LIBRARIES}
 		)
 
 IF (RESVG_FOUND)

tests/CMakeLists.txt

@@ -128,20 +128,6 @@ IF (ENABLE_BLACKMAGIC)
 ENDIF (ENABLE_BLACKMAGIC)
 
 
-################### ZEROMQ #####################
-# Find ZeroMQ library (used for socket communication & logging)
-
-# Some platforms package the header-only cppzmq C++ bindings separately,
-# others (Ubuntu) bundle them in with libzmq itself
-find_package(cppzmq QUIET)
-FIND_PACKAGE(ZMQ REQUIRED)
-
-# Include ZeroMQ headers (needed for compile)
-include_directories(${ZMQ_INCLUDE_DIRS})
-if (cppzmq_FOUND)
-    include_directories(${cppzmq_INCLUDE_DIRS})
-endif()
-
 ################### RESVG #####################
 # Find resvg library (used for rendering svg files)
 FIND_PACKAGE(RESVG)