add python ffi example wrapper code

CMakeLists.txt

@@ -59,6 +59,7 @@ add_library(${SHARED_LIB} SHARED ${LIB_SRC})
 
 add_executable(${EXE} ${EXE_SRC})
 target_link_libraries(${EXE} ${STATIC_LIB} ${LIBS})
+target_link_libraries(${SHARED_LIB} ${LIBS})
 
 add_executable(rcutil daemon/rcutil.cpp)
 target_link_libraries(rcutil ${STATIC_LIB} ${LIBS})

contrib/py/ffi-example/llarp.py

@@ -0,0 +1,41 @@
+#!/usr/bin/env python3
+
+
+from ctypes import *
+import signal
+import time
+import threading
+
+class LLARP(threading.Thread):
+
+    lib = None
+    ctx = None
+    
+    def signal(self, sig):
+        if self.ctx and self.lib:     
+            self.lib.llarp_main_signal(self.ctx, int(sig))
+            
+    def run(self):
+        code = self.lib.llarp_main_run(self.ctx)
+        print ("llarp_main_run exited with status {}".format(code))
+            
+
+def main():
+    llarp = LLARP()
+    llarp.lib = CDLL("./libllarp.so")
+    llarp.ctx = llarp.lib.llarp_main_init(b'daemon.ini')
+    if llarp.ctx:
+        llarp.start()
+        try:
+            while True:
+                print("busy loop")
+                time.sleep(1)
+        except KeyboardInterrupt:
+            llarp.signal(signal.SIGINT)
+        finally:
+            llarp.lib.llarp_main_free(llarp.ctx)
+            return
+
+if __name__ == '__main__':
+    main()
+    

daemon/main.cpp

@@ -17,10 +17,13 @@ main(int argc, char *argv[])
   const char *conffname = "daemon.ini";
   if(argc > 1)
     conffname = argv[1];
-
-  if(llarp_main_init(&ctx, conffname))
+  ctx      = llarp_main_init(conffname);
+  int code = 1;
+  if(ctx)
   {
     signal(SIGINT, handle_signal);
-    return llarp_main_run(ctx);
+    code = llarp_main_run(ctx);
+    llarp_main_free(ctx);
   }
+  return code;
 }

include/llarp.h

@@ -15,8 +15,8 @@ extern "C" {
 struct llarp_main;
 
 /** initialize application context and load config */
-bool
-llarp_main_init(struct llarp_main **ptr, const char *fname);
+struct llarp_main *
+llarp_main_init(const char *fname);
 
 /** handle signal for main context */
 void
@@ -27,7 +27,7 @@ int
 llarp_main_run(struct llarp_main *ptr);
 
 void
-llarp_main_free(struct llarp_main **ptr);
+llarp_main_free(struct llarp_main *ptr);
 
 #ifdef __cplusplus
 }

llarp/context.cpp

@@ -211,11 +211,11 @@ struct llarp_main
   std::unique_ptr< llarp::Context > ctx;
 };
 
-bool
-llarp_main_init(struct llarp_main **ptr, const char *fname)
+struct llarp_main *
+llarp_main_init(const char *fname)
 {
   if(!fname)
-    return false;
+    return nullptr;
 
   llarp_main *m = new llarp_main;
   m->ctx.reset(new llarp::Context(std::cout));
@@ -223,10 +223,9 @@ llarp_main_init(struct llarp_main **ptr, const char *fname)
   {
     m->ctx->Close();
     delete m;
-    return false;
+    return nullptr;
   }
-  *ptr = m;
-  return true;
+  return m;
 }
 
 void
@@ -238,16 +237,13 @@ llarp_main_signal(struct llarp_main *ptr, int sig)
 int
 llarp_main_run(struct llarp_main *ptr)
 {
-  auto code = ptr->ctx->Run();
-  ptr->ctx->Close();
-  return code;
+  return ptr->ctx->Run();
 }
 
 void
-llarp_main_free(struct llarp_main **ptr)
+llarp_main_free(struct llarp_main *ptr)
 {
-  if(*ptr)
-    delete *ptr;
-  *ptr = nullptr;
+  ptr->ctx->Close();
+  delete ptr;
 }
 }