[wpinet] Add option to use directly linked Avahi from cmake (#8469)

.clang-tidy

@@ -68,4 +68,7 @@ Checks:
   modernize-use-override,
   modernize-use-using,
   readability-braces-around-statements'
+CheckOptions:
+  - key: modernize-use-using.IgnoreExternC
+    value: 'true'
 FormatStyle: file

CMakeLists.txt

@@ -96,6 +96,7 @@ option(WITH_BENCHMARK "Build the benchmark project" ON)
 option(USE_SYSTEM_FMTLIB "Use system fmtlib" OFF)
 option(USE_SYSTEM_LIBUV "Use system libuv" OFF)
 option(USE_SYSTEM_EIGEN "Use system eigen" OFF)
+option(USE_LINKED_AVAHI "Use directly linked Avahi instead of loading at runtime" OFF)
 
 # Options for location of OpenCV Java.
 set(OPENCV_JAVA_INSTALL_DIR "" CACHE PATH "Location to search for the OpenCV jar file")

wpinet/CMakeLists.txt

@@ -128,6 +128,21 @@ target_compile_features(wpinet PUBLIC cxx_std_20)
 wpilib_target_warnings(wpinet)
 target_link_libraries(wpinet PUBLIC wpiutil)
 
+if(USE_LINKED_AVAHI)
+    find_library(AVAHI_COMMON REQUIRED NAMES avahi-common)
+    if(AVAHI_COMMON)
+        message(STATUS "Found avahi common: ${AVAHI_COMMON}")
+    endif()
+
+    find_library(AVAHI_CLIENT REQUIRED NAMES avahi-client)
+    if(AVAHI_CLIENT)
+        message(STATUS "Found avahi client: ${AVAHI_CLIENT}")
+    endif()
+
+    target_link_libraries(wpinet PUBLIC ${AVAHI_COMMON} ${AVAHI_CLIENT})
+    target_compile_definitions(wpinet PRIVATE DIRECT_LINK_AVAHI)
+endif()
+
 if(NOT USE_SYSTEM_LIBUV)
     target_sources(wpinet PRIVATE ${uv_native_src})
     install(

wpinet/src/main/native/linux/AvahiClient.cpp

@@ -11,6 +11,9 @@
 
 using namespace wpi::net;
 
+#ifdef DIRECT_LINK_AVAHI
+#define AvahiFunctionLoad(snake_name) snake_name = &::avahi_##snake_name
+#else
 #define AvahiFunctionLoad(snake_name)                                          \
   do {                                                                         \
     snake_name =                                                               \
@@ -19,6 +22,7 @@ using namespace wpi::net;
       return;                                                                  \
     }                                                                          \
   } while (false)
+#endif
 
 AvahiFunctionTable::AvahiFunctionTable() {
   void* lib = dlopen("libavahi-common.so.3", RTLD_LAZY);

wpinet/src/main/native/linux/AvahiClient.hpp

@@ -8,6 +8,20 @@
 
 #include <memory>
 
+#ifdef DIRECT_LINK_AVAHI
+#include "avahi-client/client.h"
+#include "avahi-client/lookup.h"
+#include "avahi-client/publish.h"
+#include "avahi-common/address.h"
+#include "avahi-common/alternative.h"
+#include "avahi-common/domain.h"
+#include "avahi-common/error.h"
+#include "avahi-common/malloc.h"
+#include "avahi-common/strlst.h"
+#include "avahi-common/thread-watch.h"
+
+#else
+
 /***
   This file is part of avahi.
   avahi is free software; you can redistribute it and/or modify it
@@ -24,6 +38,8 @@
   USA.
 ***/
 
+extern "C" {
+
 typedef struct AvahiPoll AvahiPoll;
 
 typedef enum {
@@ -223,6 +239,10 @@ enum {
   AVAHI_ERR_MAX = -54
 };
 
+}  // extern "C"
+
+#endif
+
 namespace wpi::net {
 class AvahiFunctionTable {
  public:
@@ -235,8 +255,8 @@ class AvahiFunctionTable {
   AvahiFunction(threaded_poll_get, const AvahiPoll*, (AvahiThreadedPoll*));
   AvahiFunction(threaded_poll_start, int, (AvahiThreadedPoll*));
   AvahiFunction(threaded_poll_stop, int, (AvahiThreadedPoll*));
-  AvahiFunction(threaded_poll_lock, int, (AvahiThreadedPoll*));
-  AvahiFunction(threaded_poll_unlock, int, (AvahiThreadedPoll*));
+  AvahiFunction(threaded_poll_lock, void, (AvahiThreadedPoll*));
+  AvahiFunction(threaded_poll_unlock, void, (AvahiThreadedPoll*));
 
   AvahiFunction(client_new, AvahiClient*,
                 (const AvahiPoll* poll_api, AvahiClientFlags flags,