feat: improve shared library build to export only public symbols

Author: franko

scripts/exports.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+# Print exported symbols for a DLL on Windows
+# from: https://nullprogram.com/blog/2021/05/31/
+set -e
+printf 'LIBRARY %s\nEXPORTS\n' "$1"
+objdump -p "$1" | awk '/^$/{t=0} {if(t)print$NF} /^\[O/{t=1}'
+

src/defs.h

@@ -11,4 +11,23 @@
 # define __END_DECLS /* empty */
 #endif
 
+#if defined(_WIN32) || defined(__CYGWIN__)
+# define _grtk_export __declspec(dllexport)
+# define _grtk_import __declspec(dllimport)
+#elif defined(__GNUC__) && (__GNUC__ >= 4)
+# define _grtk_export __attribute__((__visibility__("default")))
+# define _grtk_import
+#else
+# define _grtk_export
+# define _grtk_import
+#endif
+
+#ifdef GRAPH_TK_COMPILATION
+# define _grtk_api _grtk_export
+#else
+# define _grtk_api _grtk_import
+#endif
+
+#define grtk_public _grtk_api extern
+
 #endif

src/lua-draw.cpp

@@ -29,6 +29,7 @@ extern "C" {
 #include "lua-compat.h"
 #include "lua-draw.h"
 #include "lua-graph.h"
+#include "lua-graph-priv.h"
 #include "text-shape.h"
 #include "lua-cpp-utils.h"
 #include "gs-types.h"

src/lua-graph-priv.h

@@ -0,0 +1,18 @@
+#ifndef LUA_GRAPH_PRIV_H
+#define LUA_GRAPH_PRIV_H
+
+#include <pthread.h>
+
+#include "defs.h"
+
+__BEGIN_DECLS
+
+extern pthread_mutex_t agg_mutex[1];
+
+#define AGG_LOCK() pthread_mutex_lock (agg_mutex);
+#define AGG_UNLOCK() pthread_mutex_unlock (agg_mutex);
+
+__END_DECLS
+
+#endif
+

src/lua-graph.cpp

@@ -23,7 +23,9 @@ extern "C" {
 #include <lauxlib.h>
 }
 
+#define GRAPH_TK_COMPILATION
 #include "lua-graph.h"
+#include "lua-graph-priv.h"
 #include "fonts.h"
 #include "window_registry.h"
 #include "lua-draw.h"

src/lua-graph.h

@@ -1,20 +1,13 @@
 #ifndef LUA_GRAPH_H
 #define LUA_GRAPH_H
 
-#include <pthread.h>
-
 #include "defs.h"
 
 __BEGIN_DECLS
 
 #include <lua.h>
 
-extern int luaopen_graphcore (lua_State *L);
-
-extern pthread_mutex_t agg_mutex[1];
-
-#define AGG_LOCK() pthread_mutex_lock (agg_mutex);
-#define AGG_UNLOCK() pthread_mutex_unlock (agg_mutex);
+grtk_public int luaopen_graphcore (lua_State *L);
 
 __END_DECLS
 

src/lua-plot.cpp

@@ -28,6 +28,7 @@ extern "C" {
 #include "lua-plot-cpp.h"
 #include "window_hooks.h"
 #include "lua-graph.h"
+#include "lua-graph-priv.h"
 #include "lua-cpp-utils.h"
 #include "bitmap-plot.h"
 #include "gs-types.h"

src/meson.build

@@ -63,6 +63,7 @@ libgraph = shared_library('graphcore',
   c_args : graph_toolkit_c_args,
   cpp_args : graph_toolkit_c_args,
   link_args : graph_toolkit_link_args,
+  gnu_symbol_visibility : 'hidden',
   name_prefix : '',
   install_dir : 'lib/lua/5.4',
   install : true,

src/window.cpp

@@ -6,6 +6,7 @@ extern "C" {
 
 #include "lua-compat.h"
 #include "lua-defs.h"
+#include "lua-graph-priv.h"
 #include "window-cpp.h"
 #include "window_registry.h"
 #include "lua-cpp-utils.h"