/// This is the main loop which handles the ScrollView-logic from the server
/// to the client. It basically loops through messages, parses them to events
/// and distributes it to the waiting handlers.
/// It is run from a different thread and synchronizes via SVSync.
void* ScrollView::MessageReceiver(void* a) {
int counter_event_id = 0; // ongoing counter
char* message = nullptr;
// Wait until a new message appears in the input stream_.
do {
message = ScrollView::GetStream()->Receive();
} while (message == nullptr);
// This is the main loop which iterates until the server is dead (strlen = -1).
// It basically parses for 3 different messagetypes and then distributes the
// events accordingly.
while (1) {
// The new event we create.
SVEvent* cur = new SVEvent;
// The ID of the corresponding window.
int window_id;
int ev_type;
int n;
// Fill the new SVEvent properly.
sscanf(message, "%d,%d,%d,%d,%d,%d,%d,%n", &window_id, &ev_type, &cur->x,
&cur->y, &cur->x_size, &cur->y_size, &cur->command_id, &n);
char* p = (message + n);
svmap_mu->Lock();
cur->window = svmap[window_id];
if (cur->window != nullptr) {
cur->parameter = new char[strlen(p) + 1];
strcpy(cur->parameter, p);
if (strlen(p) > 0) { // remove the last \n
cur->parameter[strlen(p)] = '\0';
}
cur->type = static_cast<SVEventType>(ev_type);
// Correct selection coordinates so x,y is the min pt and size is +ve.
if (cur->x_size > 0)
cur->x -= cur->x_size;
else
cur->x_size = -cur->x_size;
if (cur->y_size > 0)
cur->y -= cur->y_size;
else
cur->y_size = -cur->y_size;
// Returned y will be the bottom-left if y is reversed.
if (cur->window->y_axis_is_reversed_)
cur->y = cur->window->TranslateYCoordinate(cur->y + cur->y_size);
cur->counter = counter_event_id;
// Increase by 2 since we will also create an SVET_ANY event from cur,
// which will have a counter_id of cur + 1 (and thus gets processed
// after cur).
counter_event_id += 2;
// In case of an SVET_EXIT event, quit the whole application.
if (ev_type == SVET_EXIT) { ScrollView::Exit(); }
// Place two copies of it in the table for the window.
cur->window->SetEvent(cur);
// Check if any of the threads currently waiting want it.
std::pair<ScrollView*, SVEventType> awaiting_list(cur->window,
cur->type);
std::pair<ScrollView*, SVEventType> awaiting_list_any(cur->window,
SVET_ANY);
std::pair<ScrollView*, SVEventType> awaiting_list_any_window((ScrollView*)nullptr,
SVET_ANY);
waiting_for_events_mu->Lock();
if (waiting_for_events.count(awaiting_list) > 0) {
waiting_for_events[awaiting_list].second = cur;
waiting_for_events[awaiting_list].first->Signal();
} else if (waiting_for_events.count(awaiting_list_any) > 0) {
waiting_for_events[awaiting_list_any].second = cur;
waiting_for_events[awaiting_list_any].first->Signal();
} else if (waiting_for_events.count(awaiting_list_any_window) > 0) {
waiting_for_events[awaiting_list_any_window].second = cur;
waiting_for_events[awaiting_list_any_window].first->Signal();
} else {
// No one wanted it, so delete it.
delete cur;
}
waiting_for_events_mu->Unlock();
// Signal the corresponding semaphore twice (for both copies).
ScrollView* sv = svmap[window_id];
if (sv != nullptr) {
sv->Signal();
sv->Signal();
}
} else {
delete cur; // Applied to no window.
}
svmap_mu->Unlock();
// Wait until a new message appears in the input stream_.
do {
message = ScrollView::GetStream()->Receive();
} while (message == nullptr);
}
return nullptr;
}
