// loads a single component in the current process.
bool ComponentLoader::loadInProcess(string file, string libname, bool log_error) {
path p(file);
char* error;
void* handle;
bool success=false;
// check if the library is already loaded
// NOTE if this library has been loaded, you can unload and reload it to apply changes (may be you have updated the dynamic library)
// anyway it is safe to do this only if there isn't any isntance whom type was loaded from this library
std::vector<LoadedLib>::iterator lib = loadedLibs.begin();
while (lib != loadedLibs.end()) {
// there is already a library with the same name
if ( lib->shortname == libname) {
log(Warning) <<"Library "<< lib->filename <<" already loaded... " ;
bool can_unload = true;
CompList::iterator cit;
for( std::vector<std::string>::iterator ctype = lib->components_type.begin(); ctype != lib->components_type.end() && can_unload; ++ctype) {
for ( cit = comps.begin(); cit != comps.end(); ++cit) {
if( (*ctype) == cit->second.type ) {
// the type of an allocated component was loaded from this library. it might be unsafe to reload the library
log(Warning) << "can NOT reload library because of the instance " << cit->second.type <<"::"<<cit->second.instance->getName() <<endlog();
can_unload = false;
}
}
}
if( can_unload ) {
log(Warning) << "try to RELOAD"<<endlog();
dlclose(lib->handle);
// remove the library info from the vector
std::vector<LoadedLib>::iterator lib_un = lib;
loadedLibs.erase(lib_un);
lib = loadedLibs.end();
}
else
return false;
}
else lib++;
}
handle = dlopen ( p.string().c_str(), RTLD_NOW | RTLD_GLOBAL );
if (!handle) {
if ( log_error ) {
log(Error) << "Could not load library '"<< p.string() <<"':"<<endlog();
log(Error) << dlerror() << endlog();
}
return false;
}
//------------- if you get here, the library has been loaded -------------
log(Debug)<<"Succesfully loaded "<<libname<<endlog();
LoadedLib loading_lib(file, libname, handle);
dlerror(); /* Clear any existing error */
// Lookup Component factories (multi component case):
FactoryMap* (*getfactory)(void) = 0;
vector<string> (*getcomponenttypes)(void) = 0;
FactoryMap* fmap = 0;
getfactory = (FactoryMap*(*)(void))( dlsym(handle, "getComponentFactoryMap") );
if ((error = dlerror()) == NULL) {
// symbol found, register factories...
fmap = (*getfactory)();
ComponentFactories::Instance().insert( fmap->begin(), fmap->end() );
log(Info) << "Loaded multi component library '"<< file <<"'"<<endlog();
getcomponenttypes = (vector<string>(*)(void))(dlsym(handle, "getComponentTypeNames"));
if ((error = dlerror()) == NULL) {
log(Debug) << "Components:";
vector<string> ctypes = getcomponenttypes();
for (vector<string>::iterator it = ctypes.begin(); it != ctypes.end(); ++it)
log(Debug) <<" "<< *it;
log(Debug) << endlog();
}
loadedLibs.push_back(loading_lib);
success = true;
}
// Lookup createComponent (single component case):
dlerror(); /* Clear any existing error */
RTT::TaskContext* (*factory)(std::string) = 0;
std::string(*tname)(void) = 0;
factory = (RTT::TaskContext*(*)(std::string))(dlsym(handle, "createComponent") );
string create_error;
error = dlerror();
if (error) create_error = error;
tname = (std::string(*)(void))(dlsym(handle, "getComponentType") );
string gettype_error;
error = dlerror();
if (error) gettype_error = error;
if ( factory && tname ) {
std::string cname = (*tname)();
if ( ComponentFactories::Instance().count(cname) == 1 ) {
log(Warning) << "Component type name "<<cname<<" already used: overriding."<<endlog();
}
ComponentFactories::Instance()[cname] = factory;
log(Info) << "Loaded component type '"<< cname <<"'"<<endlog();
loading_lib.components_type.push_back( cname );
loadedLibs.push_back(loading_lib);
success = true;
}
if (success) return true;
log(Error) <<"Unloading "<< loading_lib.filename <<": not a valid component library:" <<endlog();
if (!create_error.empty())
log(Error) << " " << create_error << endlog();
if (!gettype_error.empty())
log(Error) << " " << gettype_error << endlog();
dlclose(handle);
return false;
}
