libporty - the net_async package
This high level package provides different functionality behind
emulated networking (sockets). This allows the user application to
implement a simple, common main loop around P_poll() that handles
all different tasks the same, unified socket-operation way. This
is achieved by running some tasks in the background, in parallel
to the caller application. These tasks are always connected to
the application using local (pollable) non-blocking sockets.
On UNIX systems, libporty implementation uses fork() for running
tasks in the background. Most systems implement copy-on-write
for memory pages thus the method is not expensive. On win32,
very simple threading is used.
libporty/net_async/abgproc.h
Run background processes. Main communication channel is the standard
input/output of the process, which is bound to the main socket. A second,
optional control socket may be created to monitor process startup/shutdown.
| call
| level
| summary
|
| P_net_async_bgproc
| high
| run a background process with stdio hooked to a socket
|
libporty/net_async/adns.h
Run a background task for resolving (hostname to IP or IP to hostname).
Requests and answers are done through the socket created. The background task
runs blocking DNS lookups sequentially.
It is possible to run multiple instances for parallel lookups, but load
balancing needs to be done on the caller's side.
The caller should use async dns to convert any hostname to ip address. Once
only ip addresses are fed into low level net calls, it is guaranteed that
no blocking will happen in those calls for DNS lookups.
| call
| level
| summary
|
| P_net_async_dns
| high
| run a background DNS resolver for asynchronous lookups
|
libporty/net_async/astdio.h
Non-blocking stdio. On some systems (win32), it is impossible to
set stdin and stdout to fully nonblocking. On those systems the
only way is to run background tasks that handles stdio in blocking manner
while working from/to a non-blocking socket. The user application is using
the other end of this non-blocking socket.
On systems that support non-blocking stdio (UNIX), no background tasks or
extra sockets are created, but fd of stdio is set to non-blocking is returned,
avoiding any overhead.