How does emacsclient create it's first frame

How does emacsclient create it's first frame

[Alex Bennee]

Hi,

I've now got a working "edit server" in elisp which will respond to
edit requests from Google Chrome. However it has a small problem when
creating new frames.

If there is a frame already visible then the (make-frame) invocation
works as expected. However as I'm running this server inside an emacs
--daemon invocation the default state if for no frame to be displayed.

Indeed if you manually try a (make-frame) in this state then emacs
will complain:

09:03 alex@trent/i686 [emacs_chrome.git] >emacsclient -e '(make-frame)'
*ERROR*: Unknown terminal type

I've been trying to find how the emacsclient causes the first frame to
appear but I'm having trouble finding the client code in the emacs src
tree. Can anyone offer any pointers as to how to do this from scratch?

-- 
Alex, homepage: http://www.bennee.com/~alex/
http://www.half-llama.co.uk

Re: How does emacsclient create it's first frame

[Pascal J. Bourguignon]

Alex Bennee <kernel-hacker@bennee.com> writes:
> I've now got a working "edit server" in elisp which will respond to
> edit requests from Google Chrome. However it has a small problem when
> creating new frames.
>
> If there is a frame already visible then the (make-frame) invocation
> works as expected. However as I'm running this server inside an emacs
> --daemon invocation the default state if for no frame to be displayed.
>
> Indeed if you manually try a (make-frame) in this state then emacs
> will complain:
>
> 09:03 alex@trent/i686 [emacs_chrome.git] >emacsclient -e '(make-frame)'
> *ERROR*: Unknown terminal type
>
> I've been trying to find how the emacsclient causes the first frame to
> appear but I'm having trouble finding the client code in the emacs src
> tree. Can anyone offer any pointers as to how to do this from scratch?

I use make-frame-on-display.

Here is a little script I use:
----(mfod)-----------------------------------------------------------------
#!/bin/bash
#**************************************************************************
#FILE:               mfod
#LANGUAGE:           bash shell
#SYSTEM:             unix
#USER-INTERFACE:     NONE
#DESCRIPTION
#    
#    Shows all the emacs servers available, and let the user select one
#    on which to open a new frame.
#    
#AUTHORS
#    <PJB> Pascal J. Bourguignon <pjb@informatimago.com>
#MODIFICATIONS
#    2009-09-12 <PJB> Created.
#BUGS
#LEGAL
#    GPL
#    
#    Copyright Pascal J. Bourguignon 2009 - 2010
#    
#    This program is free software; you can redistribute it and/or
#    modify it under the terms of the GNU General Public License
#    as published by the Free Software Foundation; either version
#    2 of the License, or (at your option) any later version.
#    
#    This program is distributed in the hope that it will be
#    useful, but WITHOUT ANY WARRANTY; without even the implied
#    warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
#    PURPOSE.  See the GNU General Public License for more details.
#    
#    You should have received a copy of the GNU General Public
#    License along with this program; if not, write to the Free
#    Software Foundation, Inc., 59 Temple Place, Suite 330,
#    Boston, MA 02111-1307 USA
#**************************************************************************

sockets=()
for socket in /tmp/emacs$UID/server /tmp/emacs$UID/server-* ; do
    if [ -r $socket ] ; then
        sockets[${#sockets[@]}]=$socket
    fi
done

servers=()
frames=()
for socket in ${sockets[@]} ; do
    frame=$(emacsclient --socket-name="${socket}" --eval '(mapcar (function frame-name)  (frame-list))' 2>/dev/null || echo DEAD)
    if [ "$frame" = "DEAD" ] ; then
        # let's check there's no emacs process at that pid
        server_pid="${socket/*server-}"
        ps -p "$server_pid" | grep -s -q emacs || rm -f "${socket}"
    else
        servers[${#servers[@]}]="${socket}"
        frames[${#frames[@]}]="${frame}"
    fi
done

case ${#servers[@]} in 
0)
    printf "There is no emacs server.\n"
    exit 0
    ;;
1)
    server=${servers[0]}
    ;;
*)
    choice=-1
    while [ $choice -lt 0 -o  ${#sockets[@]} -le $choice ] ; do
        i=0
        while [ $i -lt ${#servers[@]} ] ; do
            printf "%2d) %-30s %s\n" "$i" "${servers[$i]}" "${frames[$i]}"
            i=$(( $i + 1 ))
        done
        read -p 'What instance do you want a frame from? ' index
        case x$index in
        x[Nn][Oo][Nn][Ee]|x[Cc][Aa][Nn][Cc][Ee][Ll]|x[Qq][Uu][Ii][Tt]|x[Aa][Bb][Oo][Rr][Tt])
            exit 0
            ;;
        x*[^0-9]*) 
            # search the index response into the frames lists.
            lindex=$( echo "$index" | tr '[:upper:]' '[:lower:]')
            choice=0
            found=no
            while [ $choice -lt ${#frames[@]} -a $found = no ] ; do 
                eval f=$(echo "${frames[$choice]}" | tr '[:upper:]' '[:lower:]')
                for frame in ${f[@]} ; do
                    if [ "$frame" = "$lindex" ] ; then
                        found=yes
                        break
                    fi
                done
                if [ $found = no ] ; then
                    choice=$(( $choice + 1 ))
                fi
            done
            if [ $found = no ] ; then
                printf "Please enter an integer between 0 and %d inclusive.\n" "$(( ${#servers[@]} - 1 ))"
                choice=-1
            fi
            ;;
        x*)
            choice=$index
            if  [ $choice -lt 0 -o  ${#servers[@]} -le $choice ] ; then
                printf "Please enter an integer between 0 and %d inclusive.\n" "$(( ${#servers[@]} - 1 ))"
            fi
            ;;
        esac
    done
    server=${servers[$choice]}
    ;;
esac

emacsclient --socket-name=${server} --no-wait --eval '(make-frame-on-display "'$DISPLAY'")'

#### THE END ####
------------------------------------------------------------------------

-- 
__Pascal Bourguignon__                     http://www.informatimago.com/

Re: How does emacsclient create it's first frame

[Alex Bennee]

2010/1/12 Pascal J. Bourguignon <pjb@informatimago.com>:
> Alex Bennee <kernel-hacker@bennee.com> writes:
>> I've now got a working "edit server" in elisp which will respond to
>> edit requests from Google Chrome. However it has a small problem when
>> creating new frames.
>
> I use make-frame-on-display.
>

Hmm, I tried that and it works sometimes. Other times the frame
appears but never displays text or focus
until I spin up another frame via emacsclient.

Does emacsclient do anything else in bringing frames to the fore?

-- 
Alex, homepage: http://www.bennee.com/~alex/
http://www.half-llama.co.uk