cg-object-id

   1 #!/usr/bin/env bash
   2 #
   3 # Get the SHA1 id of an object associated with the given symbolic id
   4 # Copyright (c) Petr Baudis, Pavel Roskin, Philip Pokorny  2005
   5 #
   6 # Resolves a given symbolic id to the raw SHA1 id (or a symbolic
   7 # description when passed the '-d' parameter). The symbolic id can be
   8 # an SHA1 id, a unique starting segment of an existing SHA1 id, a ref
   9 # name, date, empty string, etc. See the 'COMMIT_ID' description in
  10 # cogito(7) for the full list.
  11 #
  12 # Normally, you do not use this command directly (except with the '-d'
  13 # parameter), but it is used in other Cogito scripts to resolve passed
  14 # object identifiers. If the ID is not provided, HEAD is assumed.  The
  15 # default behavior is to show the commit ID, but you should always
  16 # explicitly write '-c' if using this in a script.
  17 #
  18 # OPTIONS
  19 # -------
  20 # -b:: Get branch name
  21 #       Get name of the current branch.
  22 #
  23 # -c:: Get commit ID
  24 #       Get ID of commit matching the object ID (error out if it is not
  25 #       a commit). This is the default if you do not pass any parameter
  26 #       as well, but that is only for the human usage. For clarity, all
  27 #       scripted usage of cg-object-id should use -c explicitly if it
  28 #       wants a commit.
  29 #
  30 # -d:: Get commit string description
  31 #       Get a commit description in form of a short string. It shows the
  32 #       most recent tag in past of the commit and if it is not the commit
  33 #       itself, it appends first few chars of the commit id to id. See
  34 #       `git-describe`(1) for details.
  35 #
  36 # -n:: Disable object type checking
  37 #       Normalize only - don't check the object type.
  38 #
  39 # -p:: Get parent commit ID(s)
  40 #       Get ID of the first parent commit of a given revision or HEAD.
  41 #       NOTE: Multiple SHA1s separated by newlines will be returned for
  42 #       commits with multiple parents.
  43 #
  44 # -t:: Get tree ID
  45 #       Get ID of tree associated with given commit or HEAD.
  46 #
  47 # OBJECT_ID::
  48 #       An ID resolving to a commit.
  49
  50 # Testsuite: Partial (used in many tests but a dedicated testsuite is missing)
  51
  52 USAGE="cg-object-id [-b | -c | -d | -n | -p | -t] [OBJECT_ID]"
  53 _git_wc_unneeded=1
  54
  55 . "${COGITO_LIB}"cg-Xlib
  56
  57
  58 # Normalize argument.  The normalized SHA1 ID is put to $normid,
  59 # type is put to $type.
  60 normalize_id()
  61 {
  62         local id="$1"
  63         local revid=
  64         local valid=
  65
  66         if [ ! "$id" ] || [ "$id" = "this" ]; then
  67                 id=HEAD;
  68         fi
  69
  70         revid="$(git-rev-parse --verify "$id" 2>/dev/null)"
  71         if [ "$revid" ] && [ ${#revid} -eq 40 ] && [ "${revid//[0-9a-f]/}" = "" ]; then
  72                 id="$revid"
  73                 valid=1
  74         fi
  75
  76         # date does the wrong thing for empty and single-letter ids
  77         if [ ${#id} -gt 1 ] && [ ! "$valid" ]; then
  78                 reqsecs="$(date --date="$id" +'%s' 2>/dev/null)"
  79
  80                 if [ "$reqsecs" ]; then
  81                         revid="$(git-rev-list "--min-age=$reqsecs" --max-count=1 HEAD)"
  82                         if [ "$revid" ]; then
  83                                 id="$revid"
  84                                 valid=1
  85                         fi
  86                 fi
  87         fi
  88
  89         # If we don't have a 40-char ID by now, it's an error
  90         if [ ! "$valid" ]; then
  91                 echo "Invalid id: $id" >&2
  92                 exit 1
  93         fi
  94
  95         type="$(git-cat-file -t "$id")"
  96         if [ "$type" = "tag" ]; then
  97                 id="$(git-cat-file tag "$id" | head -n 1)"
  98                 id="${id#object }"
  99                 type=
 100         fi
 101
 102         normid="$id"
 103 }
 104
 105
 106
 107 show_commit= # this is really only for the options-exclusivity-checking
 108 describe=
 109 show_parent=
 110 show_tree=
 111 normalize_only=
 112 while optparse; do
 113         if optparse -b; then
 114                 # one-shot
 115                 echo "$_git_head"
 116                 exit
 117         elif optparse -c; then
 118                 show_commit=1
 119         elif optparse -d; then
 120                 describe=1
 121         elif optparse -n; then
 122                 normalize_only=1
 123         elif optparse -p; then
 124                 show_parent=1
 125         elif optparse -t; then
 126                 show_tree=1
 127         else
 128                 optfail
 129         fi
 130 done
 131
 132 # Compatibility code
 133 case "$_cg_cmd" in
 134         *parent*) show_parent=1;;
 135         *tree*) show_tree=1;;
 136 esac
 137
 138 case "$show_commit$describe$show_parent$show_tree$normalize_only" in
 139         11*)    usage;;
 140 esac
 141
 142 id="${ARGS[0]}"
 143 normalize_id "$id"
 144
 145 if [ "$normalize_only" ]; then
 146         echo "$normid"
 147         exit 0
 148 fi
 149 if [ "$describe" ]; then
 150         git-describe "$normid"
 151         exit 0
 152 fi
 153
 154
 155 if [ "$show_parent" ]; then
 156         git-rev-list --parents -n 1 "$normid" | tr ' ' '\n' | tail -n +2
 157         exit 0
 158 fi
 159
 160 [ "$type" ] || type="$(git-cat-file -t "$normid")"
 161 if [ "$show_tree" ]; then
 162         if [ "$type" = "commit" ]; then
 163                 normid="$(git-cat-file commit "$normid" | sed -e 's/tree //;q')"
 164                 type="$(git-cat-file -t "$normid")"
 165         fi
 166
 167         if [ "$type" != "tree" ]; then
 168                 echo "Invalid tree id: $normid" >&2
 169                 exit 1
 170         fi
 171 else
 172         if [ "$type" != "commit" ]; then
 173                 echo "Invalid commit id: $normid" >&2
 174                 exit 1
 175         fi
 176 fi
 177
 178 echo "$normid"