Raise window holding swap file

Question

From time to time while working on multiple projects, and / or what ever, it leaves me with (too) many Vim instances open – as happens, I open a file which already is opened elsewhere, leaving me with the option of:

[O]pen Read-only, (E)dit anyway, (R)ecover, (Q)uit, (A)bort

Is there some built in way to raise the instance, as in GUI / terminal, holding the open file? Ideally bringing the file in question to the foreground (if multiple buffers).

As of now I am using a bash script that extract PID from swap, check if that PID belongs to Vim, and if so uses wmctrl to raise the window. While this works fine, at least for GUI and on X11 Linux, I am asking if there is a more native way.

Answer 1

One solution would be to use a single instance of vim per project, which would prevent this issue unless your multiple projects had overlapping files.

I'm going to assume that you are looking for a automated solution, instead of a suggestion on changing your behavior though.

There is the possibility of another solution in FocusLost that is more native to vim.

The FocusLost autocommand event works in GUI Vim, and in some console terminals. You could, instead of switching to the file in the version of vim which is open (which, if you are using multiple gui windows is messy), persist any changes that weren't written in the other instance of vim are not lost (a separate git branch, save then undo so it's in the undo tree, or simply saving it) and open it in the new instance with an indication that it was opened before.

Another potentially useful autocommand event, available in vim 7, is SwapExists, which indicates that a swap file exists for the file, IE it's open.

If you kept everything in tmux or screen, there is probably a way to switch to the appropriate window/pane.

A brief github search also brings up https://github.com/lynnard/editexisting.vim which seems to work for specific window managers like Xmonad.

Answer 2

Long lost and almost forgotten.

Meant to re-factor the code etc. but post is as is. This code is used on a 32-bit system. Not sure how it would behave on 64-bit (or other).

Have a hack in C-code somewhere as well, (extracting PID).

Leave it as a post for anyone to hack and tweak. My current script as a whole (using pid as option it should work on any GUI given it's “GUI-PID/Program” and the use of wmctrl -l -p and so on):

#!/bin/bash
# Please leave in place:
# http://vi.stackexchange.com/q/562/220

declare -i debug=1
declare -i pid=0
opt=j

# Usage
usage()
{
    printf "Usage: %s [[opt] <PID>] | [[opt] <SWP>]\n" "${0/*\//}"
    printf "\nopt:\n"
    printf "   j   : Jump to window. (Default)\n"
    printf "   g   : Get window. (E.g. from other workspace.)\n"
    printf "   l   : List windows.\n"
    printf "   p   : Only print. (With some extra info.)\n"
    printf "   s   : Alias for j. (switch)\n"
    printf "   i   : Alias for p. (information)\n"
    printf "   h   : This help.\n"
    printf "\n"
    printf "  <PID>: Process ID.\n"
    printf "  <SWP>: Read PID from Vim swap file.\n"
    if (($#)); then
        printf "\nERR: Unknown option %s\n" "$1"
    fi
}

# Check if PID is a (G)Vim process
check_vim_pid()
{
    local comm=
    if ! [[ "$1" =~ ^[0-9]+$ ]];then
        printf "ERR: Some weird thing has happened (P: $1).\n" >&2
        exit 1
    fi
    comm="$(ps -p $1 -o comm=)"
    [[ "$comm" =~ ^g?vim$ ]] && return 0 || return 1
}

# First two bytes should be b0, bc or bC
# Or in hex 0x6230, 0x6263 or 0x6243
check_b0()
{
    local b01="${1:0:2}"
    local b02="${1:2:2}"

    if [[ $b01 != '62' ]] ||
        ([[ "$b02" != '30' && "$b02" != '63' && "$b02" != '43' ]]); then
        return 1
    fi
    return 0
}

# Read PID from swap file.
# Se notes below for information.
vim_file=""
vim_swp_pid()
{
    local swp="$1"

    if ! [[ -r "$swp" ]]; then
        printf "ERR: Not able to read $swp.\n" >&2
        exit 2
    fi

    # Read b0 ID
    local b0_id="$(xxd -l 2 -p "$swp")"
    if ! check_b0 "$b0_id"; then
        printf "ERR: Bad b0 ID in file (Not Vim-swap?): %s\n" "$b0_id" >&2
        exit 3
    fi
    # Read PID from .swp file
    local -a opid=($(xxd -s 24 -l 4 -p -c 1 "$swp"))
    # Read int magic from .swp file
    local magic=$(xxd -s 1008 -l 8 -p "$swp")

    if [[ "${magic:0:8}" == "33323130" ]]; then
        # Intel (LittleEndian)
        pid=$(printf "%d" "0x${opid[3]}${opid[2]}${opid[1]}${opid[0]}")
    elif [[ "${magic:0:8}" == "30313233" ]] ||
        [[ "${magic:8:8}" == "30313233" ]]; then
        # Motorola (BigEndian)
        pid=$(printf "%d" "0x${opid[0]}${opid[1]}${opid[2]}${opid[3]}")
    else
        printf "ERR: Unknown byteroder: %s\n" "$magic" >&2
        exit 4
    fi
    if ! check_vim_pid $pid; then
        printf "N010: PID %d is not a Vim process.\n" "$pid" >&2
        exit 10
    fi
    # Read file name
    vim_file="$(xxd -s 108 -l 800 -ps "$1" | xxd -r -p)"
}

list_windows()
{
    local winid desk pid host title comm
    printf "%-10s %-3s %-6s %-16s %s\n" "WINID" "DSK" "PID" "COMM" "TITLE"
    while IFS=$' \n' read -r winid desk pid host title; do
        cf="/proc/$pid/comm"
        [[ -r "$cf" ]] && read -r comm < "$cf"
        printf "%10s %3d %6d %-16s %s\n" "$winid" "$desk" "$pid" "$comm" "$title"
    done <<< "$(wmctrl -lp)"
}
# ------------------------- RUN -------------------------------------------- #

# Check if any arguments (a bit redundant, but OK)
if [[ -z "$1" ]]; then
    usage >&2
    exit 1
fi

# Loop arguments
while [[ "$1" ]]; do
    if [[ "$1" =~ ^[0-9]+$ ]]; then
        pid=$1
    else
        [[ "${1:0:1}" == "-" ]] && op=${1:1} || op=$1
        case "$op" in
        l) list_windows; exit 0;;
        d) debug=1;;
        h|-help) usage; exit 0;;
        j|s|g|p|i) opt=$op;;
        *)
            if ! [[ -e "$1" ]]; then
                usage >&2;
                printf "\nE006: Can't stat \`%s'\n" "$1" >&2
                exit 2
            fi
            vim_swp_pid "$1"
            ;;
        esac
    fi
    shift
done

# Check if PID is set
if !(($pid)); then
    usage >&2
    printf "E011: PID required / Not found.\n" >&2
    exit 11
fi

# Read WindowID, Workspace, PID of all-windows then filter by PID
read -r wid ws <<<$(wmctrl -l -p | awk -v p="$pid" '$3 == p {print $1,"\t",$2}')

pikoli()
{
    local pp=$1
    while :; do
        awk '/^PPid:/{print $2;next}/^Name:/{print $2;next}' /proc/$pp/status 2>/dev/null || return
        pp=$(awk '/^PPid:/{print $2;next}' /proc/$pp/status)
    done
}

if ! [[ "$wid" ]]; then
    pikoli $pid
    printf "ERR: Window not fround from PID %d.\n" "$pid" >&2
    exit 12
fi

# As most DM's names desktops from 1 and not 0, a more user-friendly number.
((dmws=ws + 1))

# Do the action!
((debug)) && printf "PID=%d, WID=%s, WS=%d\n" "$pid" "$wid" "$ws"
case "$opt" in
j|s)    printf "Swithching to workspace %d raising window %s by PID %d.\n" \
        "$dmws" "$wid" "$pid";
    wmctrl -ia "$wid"
    ;;
g)    printf "Getting window %s by PID %d from workspace %d.\n" \
        "$wid" "$pid" "$dmws";
    wmctrl -iR "$wid"
    ;;
i|p)    printf "Window is on workspace %d having window ID %s by PID %d.\n" \
        "$dmws" "$wid" "$pid";
    xwininfo -id $wid
    ;;
esac

exit 0

#############################################################################
# ----------------- Vim swap file block zero format ----------------------- #
#############################################################################
#
# No script / bash code beyond here
#

NOTES 'memline.c:139':

:62
#define BLOCK0_ID0     'b'          /* block 0 id 0 */
#define BLOCK0_ID1     '0'          /* block 0 id 1 */
#define BLOCK0_ID1_C0  'c'          /* block 0 id 1 'cm' 0 */
#define BLOCK0_ID1_C1  'C'          /* block 0 id 1 'cm' 1 */

:124
#define B0_FNAME_SIZE_ORG   900 /* what it was in older versions */
#define B0_FNAME_SIZE_NOCRYPT   898 /* 2 bytes used for other things */
#define B0_FNAME_SIZE_CRYPT 890 /* 10 bytes used for other things */
#define B0_UNAME_SIZE       40
#define B0_HNAME_SIZE       40
/*
 * Restrict the numbers to 32 bits, otherwise most compilers will complain.
 * This won\'t detect a 64 bit machine that only swaps a byte in the top 32
 * bits, but that is crazy anyway.
 */
#define B0_MAGIC_LONG   0x30313233L
#define B0_MAGIC_INT    0x20212223L
#define B0_MAGIC_SHORT  0x10111213L
#define B0_MAGIC_CHAR   0x55

:139
/*
 * Block zero holds all info about the swap file.
 *
 * NOTE: DEFINITION OF BLOCK 0 SHOULD NOT CHANGE! It would make all existing
 * swap files unusable!
 *
 * If size of block0 changes anyway, adjust MIN_SWAP_PAGE_SIZE in vim.h!!
 *
 * This block is built up of single bytes, to make it portable across
 * different machines. b0_magic_* is used to check the byte order and size of
 * variables, because the rest of the swap file is not portable.
 */
struct block0
{
    char_u  b0_id[2];   /* id for block 0: BLOCK0_ID0 and BLOCK0_ID1,
                 * BLOCK0_ID1_C0, BLOCK0_ID1_C1 */
    char_u  b0_version[10]; /* Vim version string */
    char_u  b0_page_size[4];/* number of bytes per page */
    char_u  b0_mtime[4];    /* last modification time of file */
    char_u  b0_ino[4];  /* inode of b0_fname */
    char_u  b0_pid[4];  /* process id of creator (or 0) */
    char_u  b0_uname[B0_UNAME_SIZE]; /* name of user (uid if no name) */
    char_u  b0_hname[B0_HNAME_SIZE]; /* host name (if it has a name) */
    char_u  b0_fname[B0_FNAME_SIZE_ORG]; /* name of file being edited */
    long    b0_magic_long;  /* check for byte order of long */
    int     b0_magic_int;   /* check for byte order of int */
    short   b0_magic_short; /* check for byte order of short */
    char_u  b0_magic_char;  /* check for last char */
};

offs    len     what
0       2       id
2       10      version
12      4       bytes per page
16      4       mtime
20      4       inode
24      4       PID or 0
28      40      name of user or uid
68      40      host name
108     900     fname
1008    4/8/    magic long*
1012    4/8/    magic int*
1016    2/      magic short*
1018    1/      magic char*

Length of magics is arch dependant.
Offset for magic, in example above, is by standard 32 bit.