tg--index-merge-one-file.sh

   1 #!/bin/sh
   2
   3 # tg--index-merge-one-file -- auto merge a file without touching working tree
   4 # Copyright (C) 2017 Kyle J. McKay
   5 # All rights reserved.
   6 # License GPLv2+
   7
   8 # $TG_TMP_DIR => location to store temporary files
   9 # $1          => stage 1 hash or empty
  10 # $2          => stage 2 hash or empty
  11 # $3          => stage 3 hash or empty
  12 # $4          => full pathname in index
  13 # $5          => stage 1 mode (6 octal digits) or empty
  14 # $6          => stage 2 mode
  15 # $7          => stage 3 mode
  16
  17 [ $# -eq 7 ] || exit 1
  18
  19 # We only handle auto merging existing files with the same mode
  20
  21 case "${1:-:}${2:-:}${3:-:}${4:-:}${5:-:}${6:-:}${7:-:}" in *":"*) exit 1; esac
  22 [ "$5" = "$6" ] && [ "$6" = "$7" ] || exit 1
  23
  24 # Check for "just-in-case" things that shouldn't get in here:
  25 #
  26 # a) all three hashes are the same (handled same as next case)
  27 # b) $2 and $3 are the same
  28 # c) $1 and $2 are the same
  29 # d) $1 and $3 are the same
  30
  31 # For the "just-in-case"s it doesn't actually matter what the mode is
  32 newhash=
  33 if [ "$2" = "$3" ]; then
  34         newhash="$2"
  35 elif [ "$1" = "$2" ]; then
  36         newhash="$3"
  37 elif [ "$1" = "$3" ]; then
  38         newhash="$2"
  39 fi
  40
  41 if [ -z "$newhash" ]; then
  42         # mode must match 100\o\o\o
  43         case "$6" in 100[0-7][0-7][0-7]);;*) exit 1; esac
  44         if [ "$4" = ".topdeps" ] || [ "$4" = ".topmsg" ]; then
  45                 # resolution for these two is always silently "ours" never a merge
  46                 newhash="$2"
  47         else
  48                 tg_tmp_dir="${TG_TMP_DIR:-/tmp}"
  49                 basef="$tg_tmp_dir/tgmerge_$$_base"
  50                 oursf="$tg_tmp_dir/tgmerge_$$_ours"
  51                 thrsf="$tg_tmp_dir/tgmerge_$$_thrs"
  52                 trap 'rm -f "$basef" "$oursf" "$thrsf"' EXIT
  53                 trap 'exit 129' HUP
  54                 trap 'exit 130' INT
  55                 trap 'exit 131' QUIT
  56                 trap 'exit 134' ABRT
  57                 trap 'exit 141' PIPE
  58                 trap 'exit 143' TERM
  59                 git cat-file blob "$1" >"$basef" || exit 1
  60                 git cat-file blob "$2" >"$oursf" || exit 1
  61                 git cat-file blob "$3" >"$thrsf" || exit 1
  62                 git merge-file --quiet "$oursf" "$basef" "$thrsf" >/dev/null 2>&1 || exit 1
  63                 printf '%s\n' "Auto-merging $4"
  64                 newhash="$(git hash-object -w --stdin <"$oursf" 2>/dev/null)"
  65         fi
  66 fi
  67
  68 [ -n "$newhash" ] || exit 1
  69 git update-index --cacheinfo "$6" "$newhash" "$4"