used for main_dispatcher only in this patch.
Dispatcher is meant to be used for Main<->any low frequency messages.
It's interface is meant to include the red_dispatcher usage:
fixed size messages per message type
some messages require an ack
Some methods are added to be used by RedDispatcher later:
dispatcher_handle_read - to be called directly by RedDispatcher epoll
based loop
dispatcher_set_opaque - to be set from red_worker pthread
dispatcher_init - allow NULL core as used by red_worker
Read and Write behavior:
Sender: blocking write, blocking read for ack (if any).
Reader: poll for any data, if such then blocking read for a
message_type and following message. repeat until poll returns
with no pending data to read.
FDO Bugzilla: 42463
add main_dispatcher, a message passing mechanism for sending messages to
the main thread. The main thread is the thread that implements
SpiceCoreInterface, which is assumed to be a single thread.
Similar to the async operation of red_worker, a socket pair is created
and used to pass messages. The messages are a fixed size to ease
parsing. A single message is defined to pass a channel_event.
RHBZ: 746950
FDBZ: 41858
This patch is 0.8 branch only, for the master branch there should be a
better approach to share code with red_dispatcher and ready the way for
later adding more threads.
cherry-pick from 0.8 80caf07e09
Conflicts:
server/reds.c
