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 if [ "$1" = "-h" ] && [ $# -eq 1 ]; then
  18         echo "\
  19 usage: ${tgname:-tg} index-merge-one-file <s1_hash> <s2_hash> <s3_hash> <path> <s1_mode> <s2_mode> <s3_mode>"
  20         exit 0
  21 fi
  22
  23 [ $# -eq 7 ] || exit 1
  24
  25 # We only handle auto merging existing files with the same mode
  26
  27 case "${1:-:}${2:-:}${3:-:}${4:-:}${5:-:}${6:-:}${7:-:}" in *":"*) exit 1; esac
  28 [ "$5" = "$6" ] && [ "$6" = "$7" ] || exit 1
  29
  30 # Check for "just-in-case" things that shouldn't get in here:
  31 #
  32 # a) all three hashes are the same (handled same as next case)
  33 # b) $2 and $3 are the same
  34 # c) $1 and $2 are the same
  35 # d) $1 and $3 are the same
  36
  37 # For the "just-in-case"s it doesn't actually matter what the mode is
  38 newhash=
  39 if [ "$2" = "$3" ]; then
  40         newhash="$2"
  41 elif [ "$1" = "$2" ]; then
  42         newhash="$3"
  43 elif [ "$1" = "$3" ]; then
  44         newhash="$2"
  45 fi
  46
  47 if [ -z "$newhash" ]; then
  48         # mode must match 100\o\o\o
  49         case "$6" in 100[0-7][0-7][0-7]);;*) exit 1; esac
  50         if [ "$4" = ".topdeps" ] || [ "$4" = ".topmsg" ]; then
  51                 # resolution for these two is always silently "ours" never a merge
  52                 newhash="$2"
  53         else
  54                 tg_tmp_dir="${TG_TMP_DIR:-/tmp}"
  55                 basef="$tg_tmp_dir/tgmerge_$$_base"
  56                 oursf="$tg_tmp_dir/tgmerge_$$_ours"
  57                 thrsf="$tg_tmp_dir/tgmerge_$$_thrs"
  58                 trap 'rm -f "$basef" "$oursf" "$thrsf"' EXIT
  59                 trap 'exit 129' HUP
  60                 trap 'exit 130' INT
  61                 trap 'exit 131' QUIT
  62                 trap 'exit 134' ABRT
  63                 trap 'exit 141' PIPE
  64                 trap 'exit 143' TERM
  65                 git cat-file blob "$1" >"$basef" || exit 1
  66                 git cat-file blob "$2" >"$oursf" || exit 1
  67                 git cat-file blob "$3" >"$thrsf" || exit 1
  68                 git merge-file --quiet "$oursf" "$basef" "$thrsf" >/dev/null 2>&1 || exit 1
  69                 printf '%s\n' "Auto-merging $4"
  70                 newhash="$(git hash-object -w --stdin <"$oursf" 2>/dev/null)"
  71         fi
  72 fi
  73
  74 [ -n "$newhash" ] || exit 1
  75 git update-index --cacheinfo "$6" "$newhash" "$4"