On Wed, Oct 01, 2008 at 03:59:59PM +0200, Jean-Marc Lasgouttes wrote:
>
> Here's a patch for a very old bug. It is not the first time that I try
> to tackle it, but it only occured to me today that the existing code
> tests a value of errno that is probably the result of another IO action
> done in the execution of the lfun (buffer-write, for example).
>
> The patch is tested and works. But since I do not really now much about
> pipes and read(), I'll wait a few days before committing.
I think that bug 1784 has to be marked as INVALID. Following the steps
of comment #1 in bug 1784, I would say that it is expected behavior.
Indeed, after
$ echo "LYXCMD:test:buffer-write" > .lyx/lyxpipe.in
the pipe gets closed and thus the connection *has* to be restarted.
Try instead the following:
$ cat - > .lyx/lyxpipe.in
LYXCMD:test:buffer-write
LYXCMD:test:open-file
^D
where ^D means hitting Ctrl-D. See? Only after ^D, which closes the
pipe, the connection is restarted.
I admit that the code is not very clear as the test on errno should
only be performed if read() returns -1. So, I would rather propose
the attached patch.
--
Enrico
Index: src/Server.cpp
===================================================================
--- src/Server.cpp (revision 26668)
+++ src/Server.cpp (working copy)
@@ -273,23 +273,29 @@ void LyXComm::read_ready()
clientcb_(client_, cmd);
//\n or not \n?
}
- }
- if (errno == EAGAIN) {
- errno = 0;
- return;
- }
- if (errno != 0) {
- LYXERR0("LyXComm: " << strerror(errno));
- if (!read_buffer_.empty()) {
- LYXERR0("LyXComm: truncated command: " <<
read_buffer_);
- read_buffer_.erase();
+ } else {
+ if (errno == EAGAIN) {
+ // Nothing to read but some process has
+ // the pipe still opened for writing
+ errno = 0;
+ return;
+ }
+ if (errno != 0) {
+ // Something weird occurred, better bailing out
+ LYXERR0("LyXComm: " << strerror(errno));
+ if (!read_buffer_.empty()) {
+ LYXERR0("LyXComm: truncated command: "
<< read_buffer_);
+ read_buffer_.erase();
+ }
+ break; // reset connection
}
- break; // reset connection
}
}
- // The connection gets reset in errno != EAGAIN
- // Why does it need to be reset if errno == 0?
+ // The connection gets reset when status == 0, meaning that
+ // the pipe opened for writing was now closed, or status < 0
+ // and errno != EAGAIN and errno != 0, meaning that something
+ // weird occurred.
closeConnection();
openConnection();
errno = 0;
