tg-export.sh

   1 #!/bin/sh
   2 # TopGit - A different patch queue manager
   3 # (c) Petr Baudis <pasky@suse.cz>  2008
   4 # GPLv2
   5
   6 name=
   7 output=
   8
   9
  10 ## Parse options
  11
  12 while [ -n "$1" ]; do
  13         arg="$1"; shift
  14         case "$arg" in
  15         -*)
  16                 echo "Usage: tg export NEWBRANCH" >&2
  17                 exit 1;;
  18         *)
  19                 [ -z "$output" ] || die "new branch already specified ($output)"
  20                 output="$arg";;
  21         esac
  22 done
  23
  24
  25 name="$(git symbolic-ref HEAD | sed 's#^refs/heads/##')"
  26 base_rev="$(git rev-parse --short --verify "refs/top-bases/$name" 2>/dev/null)" ||
  27         die "not on a TopGit-controlled branch"
  28
  29 [ -n "$output" ] ||
  30         die "no target branch specified"
  31
  32 ! git rev-parse --verify "$output" >/dev/null 2>&1 ||
  33         die "target branch '$output' already exists; first run: git branch -D $output"
  34
  35
  36 playground="$(mktemp -d)"
  37 trap 'rm -rf "$playground"' EXIT
  38
  39 # Trusty Cogito code:
  40 load_author()
  41 {
  42         if [ -z "$GIT_AUTHOR_NAME" ] && echo "$1" | grep -q '^[^< ]'; then
  43                 export GIT_AUTHOR_NAME="$(echo "$1" | sed 's/ *<.*//')"
  44         fi
  45         if [ -z "$GIT_AUTHOR_EMAIL" ] && echo "$1" | grep -q '<.*>'; then
  46                 export GIT_AUTHOR_EMAIL="$(echo "$1" | sed 's/.*<\(.*\)>.*/\1/')"
  47         fi
  48 }
  49
  50 # pretty_tree NAME
  51 # Output tree ID of a cleaned-up tree without tg's artifacts.
  52 pretty_tree()
  53 {
  54         (export GIT_INDEX_FILE="$playground/^index"
  55          git read-tree "$1"
  56          git update-index --force-remove ".topmsg" ".topdeps"
  57          git write-tree)
  58 }
  59
  60 # collapsed_commit NAME
  61 # Produce a collapsed commit of branch NAME.
  62 collapsed_commit()
  63 {
  64         name="$1"
  65
  66         rm -f "$playground/^pre" "$playground/^post"
  67         >"$playground/^body"
  68
  69         # Get commit message and authorship information
  70         git cat-file blob "$name:.topmsg" >"$playground/^msg"
  71         while read line; do
  72                 if [ -z "$line" ]; then
  73                         # end of header
  74                         cat >"$playground/^body"
  75                         break
  76                 fi
  77                 case "$line" in
  78                 From:*) load_author "${line#From: }";;
  79                 Subject:*) echo "${line#Subject: }" >>"$playground/^pre";;
  80                 *) echo "$line" >>"$playground/^post";;
  81                 esac
  82         done <"$playground/^msg"
  83
  84         # Determine parent
  85         parent="$(cut -f 1 "$playground/$name^parents")"
  86         if [ "$(cat "$playground/$name^parents" | wc -l)" -gt 1 ]; then
  87                 # Produce a merge commit first
  88                 parent="$({
  89                         echo "TopGit-driven merge of branches:"
  90                         echo
  91                         cut -f 2 "$playground/$name^parents"
  92                 } | git commit-tree "$(pretty_tree "refs/top-bases/$name")" \
  93                         $(for p in $parent; do echo -p $p; done))"
  94         fi
  95
  96         {
  97                 if [ -s "$playground/^pre" ]; then
  98                         cat "$playground/^pre"
  99                         echo
 100                 fi
 101                 cat "$playground/^body"
 102                 [ ! -s "$playground/^post" ] || cat "$playground/^post"
 103         } | git commit-tree "$(pretty_tree "$name")" -p "$parent"
 104
 105         echo "$name" >>"$playground/^ticker"
 106 }
 107
 108 # collapse_one
 109 # This will collapse a single branch, using information about
 110 # previously collapsed branches stored in $playground.
 111 collapse_one()
 112 {
 113         branch_needs_update >/dev/null
 114         [ "$_ret" -eq 0 ] ||
 115                 die "cancelling $_ret export of $_dep (-> $_name): branch not up-to-date"
 116
 117         if [ -s "$playground/$_dep" ]; then
 118                 # We've already seen this dep
 119                 commit="$(cat "$playground/$_dep")"
 120
 121         elif [ -z "$_dep_is_tgish" ]; then
 122                 # This dep is not for rewrite
 123                 commit="$(git rev-parse --verify "$_dep")"
 124
 125         else
 126                 # First time hitting this dep; the common case
 127                 commit="$(collapsed_commit "$_dep")"
 128
 129                 mkdir -p "$playground/$(dirname "$_dep")"
 130                 echo "$commit" >"$playground/$_dep"
 131                 echo "Collapsed $_dep"
 132         fi
 133
 134         # Propagate our work through the dependency chain
 135         mkdir -p "$playground/$(dirname "$_name")"
 136         echo "$commit   $_dep" >>"$playground/$_name^parents"
 137 }
 138
 139 # Collapse all the branches - this way, collapse_one will be
 140 # called in topological order.
 141 recurse_deps collapse_one "$name"
 142 (_ret=0; _dep="$name"; _name=""; _dep_is_tgish=1; collapse_one)
 143
 144 git update-ref "refs/heads/$output" "$(cat "$playground/$name")"
 145
 146 depcount="$(cat "$playground/^ticker" | wc -l)"
 147 echo "Exported topic branch $name (total $depcount topics) to branch $output"