Re: DocView: process ps->pdf changed status to killed.

[Tassilo Horn]

Stefan Monnier <monnier@IRO.UMontreal.CA> writes:

>> The problem is that if your emacs doesn't satisfy the doc-view
>> requirements (PNG support, graphical frame, conversion utilities) but
>> you have pdf2text installed, then you're asked if you want to view the
>> document as plain text instead.  If you say yes, then doc-view will
>> start a process to do the conversion.
>> But right after starting that process, `doc-view-toggle-display' is
>> called which will kill all running doc-view processes (including the
>> conversion to TXT) and put the document's buffer back in its normal
>> editing mode.  That's why you've got the message that the process was
>> killed.
>
> It seems like it's an error to put the "put the document's buffer back
> in its normal editing mode" if the user agreed to "view the document
> as plain text".  IOW the core of the problem might be that we
> shouldn't call `doc-view-toggle-display' in that case?

No, I don't think so.  For example, visit a postscript document in a
terminal so that doc-view cannot do its normal workings.  Do M-x
doc-view-mode RET.  Now you're told that this won't work and if you want
to view the doc's text instead.  Say yes.  In the meantime, the original
buffer has switched doc-view-mode which means read-only, no font-lock,
etc.

Since `doc-view-toggle-display' is called, the original buffer will be
switched back to `ps-mode'.  If we'd omit that, the buffer would stay in
doc-view-mode and basically be useless.

> I don't understand why running the process synchronously helps, and it
> sounds like a workaround rather than a fix.

The text contents of the document are opened in a separate buffer, not
in the buffer of the original document.  By doing the conversion
synchronously the switching back from doc-view-mode to, say, ps-mode in
the original buffer is deferred until that conversion has finished (and
thus all the doc-view buffer local variables aren't needed anymore).

Bye,
Tassilo