Merge pull request #527 from adamharrison/native-interop

Native Plugins

src/api/system.c

@@ -651,6 +651,85 @@ static int f_set_window_opacity(lua_State *L) {
   return 1;
 }
 
+// Symbol table for native plugin loading. Allows for a statically
+// bound lua library to be used by native plugins.
+typedef struct {
+  const char* symbol;
+  void* address;
+} lua_function_node;
+
+#define P(FUNC) { "lua_" #FUNC, (void*)(lua_##FUNC) }
+#define U(FUNC) { "luaL_" #FUNC, (void*)(luaL_##FUNC) }
+static void* api_require(const char* symbol) {
+  static lua_function_node nodes[] = {
+    P(absindex), P(arith), P(atpanic), P(callk), P(checkstack), 
+    P(close), P(compare), P(concat), P(copy), P(createtable), P(dump), 
+    P(error),  P(gc), P(getallocf), P(getctx), P(getfield), P(getglobal),
+    P(gethook), P(gethookcount), P(gethookmask), P(getinfo), P(getlocal),
+    P(getmetatable), P(getstack), P(gettable), P(gettop), P(getupvalue),
+    P(getuservalue), P(insert), P(isnumber), P(isstring), P(isuserdata), 
+    P(len), P(load), P(newstate), P(newthread), P(newuserdata), P(next), 
+    P(pcallk), P(pushboolean), P(pushcclosure), P(pushfstring), P(pushinteger),
+    P(pushlightuserdata), P(pushlstring), P(pushnil), P(pushnumber), 
+    P(pushstring), P(pushthread), P(pushunsigned), P(pushvalue), 
+    P(pushvfstring), P(rawequal), P(rawget), P(rawgeti), P(rawgetp), P(rawlen),
+    P(rawset), P(rawseti), P(rawsetp), P(remove), P(replace), P(resume), 
+    P(setallocf), P(setfield), P(setglobal), P(sethook), P(setlocal), 
+    P(setmetatable), P(settable), P(settop), P(setupvalue), P(setuservalue), 
+    P(status), P(tocfunction), P(tointegerx), P(tolstring), P(toboolean),
+    P(tonumberx), P(topointer), P(tothread),  P(tounsignedx), P(touserdata),
+    P(type), P(typename), P(upvalueid), P(upvaluejoin), P(version), P(xmove), 
+    P(yieldk), U(checkversion_), U(getmetafield), U(callmeta), U(tolstring), 
+    U(argerror), U(checknumber), U(optnumber), U(checkinteger), 
+    U(checkunsigned), U(checkstack), U(checktype), U(checkany), 
+    U(newmetatable), U(setmetatable), U(testudata), U(checkudata), U(where),
+    U(error), U(fileresult), U(execresult), U(ref), U(unref), U(loadstring), 
+    U(newstate), U(len), U(setfuncs), U(getsubtable), U(buffinit), 
+    U(prepbuffsize), U(addlstring), U(addstring), U(addvalue), U(pushresult),
+    U(pushresultsize), U(buffinitsize)
+  };
+  for (int i = 0; i < sizeof(nodes) / sizeof(lua_function_node); ++i) {
+    if (strcmp(nodes[i].symbol, symbol) == 0)
+      return nodes[i].address;
+  }
+  return NULL;
+}
+
+static int f_load_native_plugin(lua_State* L) {
+  size_t sname, namelen, pathlen;
+  int results;
+  char olib[512]; olib[sizeof(olib)-1] = 0;
+  const char* name = luaL_checklstring(L, -2, &namelen);
+  const char* path = luaL_checklstring(L, -1, &pathlen);
+  void* library = SDL_LoadObject(path);
+  if (name == 0 || !library)
+    return luaL_error(L, "Unable to load %s: %s", name, SDL_GetError());
+  lua_getglobal(L, "package");
+  lua_getfield(L, -1, "native_plugins");
+  lua_pushlightuserdata(L, library);
+  lua_setfield(L, -2, name);
+  lua_pop(L, 1);
+  for (sname = namelen - 1; sname > 0 && name[sname] != '.'; --sname);
+  snprintf(olib, sizeof(olib), "lua_open_lite_xl_%s", &name[sname+1]); 
+  int (*ext_entrypoint)(lua_State* L, void*) = SDL_LoadFunction(library, olib);
+  if (!ext_entrypoint) {
+    snprintf(olib, sizeof(olib), "lua_open_%s", &name[sname+1]);
+    int (*entrypoint)(lua_State* L) = SDL_LoadFunction(library, olib);
+    if (!entrypoint) {
+      return luaL_error(L, "Unable to load %s: Can't find entrypoint. Requires a "
+        "function defined as int lua_open_lite_xl_%s(lua_State* L, void* XL)", 
+        name, &name[sname+1]);
+    }
+    results = entrypoint(L);
+  } else {
+    results = ext_entrypoint(L, api_require);
+  }
+  if (!results)
+    return luaL_error(L, "Unable to load %s: Your entrypoint must return at "
+    " least one value.", name);
+  return results;
+}
+
 
 static const luaL_Reg lib[] = {
   { "poll_event",          f_poll_event          },
@@ -678,6 +757,7 @@ static const luaL_Reg lib[] = {
   { "exec",                f_exec                },
   { "fuzzy_match",         f_fuzzy_match         },
   { "set_window_opacity",  f_set_window_opacity  },
+  { "load_native_plugin",  f_load_native_plugin  },
   { NULL, NULL }
 };
 

src/main.c

@@ -140,8 +140,6 @@ init_lua:
   lua_setglobal(L, "EXEFILE");
 
 #ifdef __APPLE__
-  lua_pushboolean(L, true);
-  lua_setglobal(L, "MACOS");
   enable_momentum_scroll();
   #ifdef MACOS_USE_BUNDLE
     set_macos_bundle_resources(L);