jobd/maintain-auto-gc-hack.sh

   1 #!/bin/sh
   2
   3 # This script is designed to be run either directly giving it a project
   4 # name or by being sourced from one of the other scripts.
   5
   6 # When sourced from another script the current directory must be set
   7 # to the top-level --git-dir of the project to operate on and the
   8 # _shlib_done variable must be set to 1 and then after sourcing the
   9 # maintain_auto_gc_hack function must be called
  10
  11 if [ -z "$_shlib_done" ]; then
  12         . @basedir@/shlib.sh
  13
  14         set -e
  15
  16         if [ $# -ne 1 ]; then
  17                 echo "Usage: maintain-auto-gc-hack.sh projname" >&2
  18                 exit 1
  19         fi
  20
  21         proj="${1%.git}"
  22         shift
  23         cd "$cfg_reporoot/$proj.git"
  24 fi
  25
  26 make_empty_git_pack() {
  27         if ! [ -f "objects/pack/$1.idx" ] || ! [ -f "objects/pack/$1.pack" ]; then
  28                 rm -f "objects/pack/$1.idx" "objects/pack/$1.pack" || :
  29                 git pack-objects -q $opts --stdout </dev/null |
  30                 git index-pack --stdin "objects/pack/$1.pack" >/dev/null || :
  31         fi
  32         ! [ -e "objects/pack/$1.keep" ] || rm -f "objects/pack/$1.keep" || :
  33 }
  34
  35 # In order to get pre-auto-gc to run we maintain the following:
  36 #   1) gc.auto=1
  37 #   2) gc.autopacklimit=1
  38 #   3) pre-auto-gc-1.pack (and .idx)
  39 #   4) pre-auto-gc-2.pack (and .idx)
  40 # In addition the following happens:
  41 #   5) post-receive and update.sh keep .refs-last updated
  42 #
  43 # The current state pre-auto-gc hack is determined by the following:
  44 #
  45 # $Girocco::Config::autogchack | repository's girocco.autogchack config | state
  46 # ---------------------------- | -------------------------------------- | -----
  47 # mirror and .nofetch exists   | don't care                             | off
  48 # false                        | don't care                             | off
  49 # true (or mirror w/o .nofetch)| true or unset                          | on
  50 # true (or mirror w/o .nofetch)| false                                  | off
  51 #
  52 # When $Girocco::Config::autogchack is the special value "mirror" it behaves
  53 # as "false" when the .nofetch file exists and "true" when it does not.
  54 #
  55 # After determining what state we should be in, we make suitable adjustments
  56 # if things are not set up properly including creating a .refs-last file
  57 #
  58 # Note that if the auto gc hack is disabled and nothing needs to be changed
  59 # then only two read-only "git config" commands get run which makes this
  60 # very low overhead considering it normally only runs at gc.sh time.
  61 maintain_auto_gc_hack() {
  62         _hackon=
  63         if
  64                 [ "${cfg_autogchack:-0}" != "0" ] &&
  65                 { [ "$cfg_autogchack" != "mirror" ] || ! [ -e .nofetch ]; } &&
  66                 [ "$(git config --get --bool girocco.autogchack 2>/dev/null)" != "false" ]
  67         then
  68                 _hackon=1
  69         fi
  70         if [ -z "$_hackon" ]; then
  71                 # Make the hack be off, but still allow pre-auto-gc to run if there are
  72                 # enough loose objects or packs in order to ensure that .needsgc gets set
  73                 rm -f .refs-last
  74                 rm -f objects/pack/pre-auto-gc-?.idx objects/pack/pre-auto-gc-?.pack || :
  75                 [ "$(git config -f config --get gc.auto)" = "3000" ] || git config gc.auto 3000 || :
  76                 [ "$(git config -f config --get gc.autopacklimit)" = "25" ] || git config gc.autopacklimit 25 || :
  77         else
  78                 # Make the hack be on
  79                 # This one may need a bit more work
  80                 # Do the .refs-last file first to make sure it's available
  81                 # before changing the settings that will cause pre-auto-gc to activate
  82                 if ! [ -e .refs-last ]; then
  83                         git for-each-ref --format '%(refname) %(objectname)' |
  84                         LC_ALL=C sort -b -k1,1 >.refs-new.$$ &&
  85                         mv -f .refs-new.$$ .refs-last || :
  86                 fi
  87                 # Make sure at least two pack files exist; they MUST NOT
  88                 # have any associated .keep files for this to work!
  89                 make_empty_git_pack "pre-auto-gc-1" || :
  90                 make_empty_git_pack "pre-auto-gc-2" || :
  91                 # Finally activate auto gc
  92                 [ "$(git config -f config --get gc.autopacklimit)" = "1" ] || git config gc.autopacklimit 1 || :
  93                 [ "$(git config -f config --get gc.auto)" = "1" ] || git config gc.auto 1 || :
  94         fi
  95 }
  96
  97 [ -n "$_shlib_done" ] || maintain_auto_gc_hack