ocean.io.select.client.EpollProcess

Posix process with epoll integration of output streams (stdout & stderr).

Usage example:

1 
2 import ocean.io.Stdout;
3 import ocean.io.select.client.EpollProcess;
4 import ocean.io.select.EpollSelectDispatcher;
5 
6 // Simple epoll process class which uses curl to download data from a
7 // url
8 class CurlProcess : EpollProcess
9 {
10     this ( EpollSelectDispatcher epoll )
11     {
12         super(epoll);
13     }
14 
15     // Starts the process downloading a url
16     public void start ( char[] url )
17     {
18         super.start("curl", [url]);
19     }
20 
21     // Called by the super class when the process sends data to stdout.
22     // (In the case of curl this is data downloaded from the url.)
23     protected void stdout ( ubyte[] data )
24     {
25         Stdout.formatln("Received: '{}'", data);
26     }
27 
28     // Called by the super class when the process sends data to stderr.
29     // (In the case of curl this is progress & error messages, which we
30     // just ignore in this example.)
31     protected void stderr ( ubyte[] data )
32     {
33     }
34 
35     // Called by the super class when the process is finished.
36     protected void finished ( bool exited_ok, int exit_code )
37     {
38         if ( exited_ok )
39         {
40             Stdout.formatln("Process exited with code {}", exit_code);
41         }
42         else
43         {
44             Stdout.formatln("Process terminated abnormally");
45         }
46     }
47 }
48 
49 // Create epoll selector instance.
50 auto epoll = new EpollSelectDispatcher;
51 
52 // Create a curl process instance.
53 auto process = new CurlProcess(epoll);
54 
55 // Start the process running, executing a curl command to download data
56 // from a url.
57 process.start("http://www.google.com");
58 
59 // Handle arriving data.
60 epoll.eventLoop;

It is sometimes desirable to use more than one EpollSelectDispatcher instance with various EpollProcess instances. One example of such usage is when an application needs to create short-lived EpollProcess instance(s) in a unittest block. In this case one EpollSelectDispatcher instance would be needed in the unittest block, and a different one in the application's main logic.

This will work provided that all processes created during the test have terminated before the main application starts.