Make backlog_size changeable across HUPs.
[cubemap] / stream.cpp
index d571578..ab10e35 100644 (file)
@@ -62,6 +62,41 @@ StreamProto Stream::serialize()
        data_fd = -1;
        return serialized;
 }
+       
+void Stream::set_backlog_size(size_t new_size)
+{
+       if (backlog_size == new_size) {
+               return;
+       }
+
+       string existing_data;
+       if (!read_tempfile(data_fd, &existing_data)) {  // Closes data_fd.
+               exit(1);
+       }
+
+       // Unwrap the data so it's no longer circular.
+       if (bytes_received <= backlog_size) {
+               existing_data.resize(bytes_received);
+       } else {
+               size_t pos = bytes_received % backlog_size;
+               existing_data = existing_data.substr(pos, string::npos) +
+                       existing_data.substr(0, pos);
+       }
+
+       // See if we need to discard data.
+       if (new_size < existing_data.size()) {
+               size_t to_discard = existing_data.size() - new_size;
+               existing_data = existing_data.substr(to_discard, string::npos);
+       }
+
+       // Create a new, empty data file.
+       data_fd = make_tempfile("");
+       backlog_size = new_size;
+
+       // Now cheat a bit by rewinding, and adding all the old data back.
+       bytes_received -= existing_data.size();
+       add_data(existing_data.data(), existing_data.size());
+}
 
 void Stream::put_client_to_sleep(Client *client)
 {
@@ -107,8 +142,6 @@ void Stream::add_data(const char *data, ssize_t bytes)
                data += ret;
                bytes -= ret;
        }
-
-       wake_up_all_clients();
 }
 
 void Stream::wake_up_all_clients()