#!/bin/sh
#

USAGE='<fetch-options> <repository> <refspec>...'
SUBDIRECTORY_OK=Yes
. git-sh-setup
set_reflog_action "fetch $*"
cd_to_toplevel ;# probably unnecessary...

. git-parse-remote
_x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
_x40="$_x40$_x40$_x40$_x40$_x40$_x40$_x40$_x40"

LF='
'
IFS="$LF"

no_tags=
tags=
append=
force=
verbose=
update_head_ok=
exec=
keep=
shallow_depth=
while case "$#" in 0) break ;; esac
do
        case "$1" in
        -a|--a|--ap|--app|--appe|--appen|--append)
                append=t
                ;;
        --upl|--uplo|--uploa|--upload|--upload-|--upload-p|\
        --upload-pa|--upload-pac|--upload-pack)
                shift
                exec="--upload-pack=$1"
                ;;
        --upl=*|--uplo=*|--uploa=*|--upload=*|\
        --upload-=*|--upload-p=*|--upload-pa=*|--upload-pac=*|--upload-pack=*)
                exec=--upload-pack=$(expr "z$1" : 'z-[^=]*=\(.*\)')
                shift
                ;;
        -f|--f|--fo|--for|--forc|--force)
                force=t
                ;;
        -t|--t|--ta|--tag|--tags)
                tags=t
                ;;
        -n|--n|--no|--no-|--no-t|--no-ta|--no-tag|--no-tags)
                no_tags=t
                ;;
        -u|--u|--up|--upd|--upda|--updat|--update|--update-|--update-h|\
        --update-he|--update-hea|--update-head|--update-head-|\
        --update-head-o|--update-head-ok)
                update_head_ok=t
                ;;
        -v|--verbose)
                verbose=Yes
                ;;
        -k|--k|--ke|--kee|--keep)
                keep='-k -k'
                ;;
        --depth=*)
                shallow_depth="--depth=`expr "z$1" : 'z-[^=]*=\(.*\)'`"
                ;;
        --depth)
                shift
                shallow_depth="--depth=$1"
                ;;
        -*)
                usage
                ;;
        *)
                break
                ;;
        esac
        shift
done

case "$#" in
0)
        origin=$(get_default_remote)
        test -n "$(get_remote_url ${origin})" ||
                die "Where do you want to fetch from today?"
        set x $origin ; shift ;;
esac

if test -z "$exec"
then
        # No command line override and we have configuration for the remote.
        exec="--upload-pack=$(get_uploadpack $1)"
fi

remote_nick="$1"
remote=$(get_remote_url "$@")
refs=
rref=
rsync_slurped_objects=

if test "" = "$append"
then
        : >"$GIT_DIR/FETCH_HEAD"
fi

# Global that is reused later
ls_remote_result=$(git ls-remote $exec "$remote") ||
        die "Cannot get the repository state from $remote"

append_fetch_head () {
    head_="$1"
    remote_="$2"
    remote_name_="$3"
    remote_nick_="$4"
    local_name_="$5"
    case "$6" in
    t) not_for_merge_='not-for-merge' ;;
    '') not_for_merge_= ;;
    esac

    # remote-nick is the URL given on the command line (or a shorthand)
    # remote-name is the $GIT_DIR relative refs/ path we computed
    # for this refspec.

    # the $note_ variable will be fed to git-fmt-merge-msg for further
    # processing.
    case "$remote_name_" in
    HEAD)
        note_= ;;
    refs/heads/*)
        note_="$(expr "$remote_name_" : 'refs/heads/\(.*\)')"
        note_="branch '$note_' of " ;;
    refs/tags/*)
        note_="$(expr "$remote_name_" : 'refs/tags/\(.*\)')"
        note_="tag '$note_' of " ;;
    refs/remotes/*)
        note_="$(expr "$remote_name_" : 'refs/remotes/\(.*\)')"
        note_="remote branch '$note_' of " ;;
    *)
        note_="$remote_name of " ;;
    esac
    remote_1_=$(expr "z$remote_" : 'z\(.*\)\.git/*$') &&
        remote_="$remote_1_"
    note_="$note_$remote_"

    # 2.6.11-tree tag would not be happy to be fed to resolve.
    if git-cat-file commit "$head_" >/dev/null 2>&1
    then
        headc_=$(git-rev-parse --verify "$head_^0") || exit
        echo "$headc_   $not_for_merge_ $note_" >>"$GIT_DIR/FETCH_HEAD"
    else
        echo "$head_    not-for-merge   $note_" >>"$GIT_DIR/FETCH_HEAD"
    fi

    update_local_ref "$local_name_" "$head_" "$note_"
}

update_local_ref () {
    # If we are storing the head locally make sure that it is
    # a fast forward (aka "reverse push").

    label_=$(git-cat-file -t $2)
    newshort_=$(git-rev-parse --short $2)
    if test -z "$1" ; then
        [ "$verbose" ] && echo >&2 "* fetched $3"
        [ "$verbose" ] && echo >&2 "  $label_: $newshort_"
        return 0
    fi
    oldshort_=$(git show-ref --hash --abbrev "$1" 2>/dev/null)

    case "$1" in
    refs/tags/*)
        # Tags need not be pointing at commits so there
        # is no way to guarantee "fast-forward" anyway.
        if test -n "$oldshort_"
        then
                if now_=$(git show-ref --hash "$1") && test "$now_" = "$2"
                then
                        [ "$verbose" ] && echo >&2 "* $1: same as $3"
                        [ "$verbose" ] && echo >&2 "  $label_: $newshort_" ||:
                else
                        echo >&2 "* $1: updating with $3"
                        echo >&2 "  $label_: $newshort_"
                        git-update-ref -m "$GIT_REFLOG_ACTION: updating tag" "$1" "$2"
                fi
        else
                echo >&2 "* $1: storing $3"
                echo >&2 "  $label_: $newshort_"
                git-update-ref -m "$GIT_REFLOG_ACTION: storing tag" "$1" "$2"
        fi
        ;;

    refs/heads/* | refs/remotes/*)
        # $1 is the ref being updated.
        # $2 is the new value for the ref.
        local=$(git-rev-parse --verify "$1^0" 2>/dev/null)
        if test "$local"
        then
            # Require fast-forward.
            mb=$(git-merge-base "$local" "$2") &&
            case "$2,$mb" in
            $local,*)
                if test -n "$verbose"
                then
                        echo >&2 "* $1: same as $3"
                        echo >&2 "  $label_: $newshort_"
                fi
                ;;
            *,$local)
                echo >&2 "* $1: fast forward to $3"
                echo >&2 "  old..new: $oldshort_..$newshort_"
                git-update-ref -m "$GIT_REFLOG_ACTION: fast-forward" "$1" "$2" "$local"
                ;;
            *)
                false
                ;;
            esac || {
                case ",$force,$single_force," in
                *,t,*)
                        echo >&2 "* $1: forcing update to non-fast forward $3"
                        echo >&2 "  old...new: $oldshort_...$newshort_"
                        git-update-ref -m "$GIT_REFLOG_ACTION: forced-update" "$1" "$2" "$local"
                        ;;
                *)
                        echo >&2 "* $1: not updating to non-fast forward $3"
                        echo >&2 "  old...new: $oldshort_...$newshort_"
                        exit 1
                        ;;
                esac
            }
        else
            echo >&2 "* $1: storing $3"
            echo >&2 "  $label_: $newshort_"
            git-update-ref -m "$GIT_REFLOG_ACTION: storing head" "$1" "$2"
        fi
        ;;
    esac
}

# updating the current HEAD with git-fetch in a bare
# repository is always fine.
if test -z "$update_head_ok" && test $(is_bare_repository) = false
then
        orig_head=$(git-rev-parse --verify HEAD 2>/dev/null)
fi

# If --tags (and later --heads or --all) is specified, then we are
# not talking about defaults stored in Pull: line of remotes or
# branches file, and just fetch those and refspecs explicitly given.
# Otherwise we do what we always did.

reflist=$(get_remote_refs_for_fetch "$@")
if test "$tags"
then
        taglist=`IFS='  ' &&
                  echo "$ls_remote_result" |
                  git-show-ref --exclude-existing=refs/tags/ |
                  while read sha1 name
                  do
                        echo ".${name}:${name}"
                  done` || exit
        if test "$#" -gt 1
        then
                # remote URL plus explicit refspecs; we need to merge them.
                reflist="$reflist$LF$taglist"
        else
                # No explicit refspecs; fetch tags only.
                reflist=$taglist
        fi
fi

fetch_native () {
  reflist="$1"
  refs=
  rref=

  for ref in $reflist
  do
      refs="$refs$LF$ref"

      # These are relative path from $GIT_DIR, typically starting at refs/
      # but may be HEAD
      if expr "z$ref" : 'z\.' >/dev/null
      then
          not_for_merge=t
          ref=$(expr "z$ref" : 'z\.\(.*\)')
      else
          not_for_merge=
      fi
      if expr "z$ref" : 'z+' >/dev/null
      then
          single_force=t
          ref=$(expr "z$ref" : 'z+\(.*\)')
      else
          single_force=
      fi
      remote_name=$(expr "z$ref" : 'z\([^:]*\):')
      local_name=$(expr "z$ref" : 'z[^:]*:\(.*\)')

      rref="$rref$LF$remote_name"
  done

    ( : subshell because we muck with IFS
      IFS="     $LF"
      (
          git-fetch-pack --thin $exec $keep $shallow_depth "$remote" $rref ||
          echo failed "$remote"
      ) |
      (
        trap '
                if test -n "$keepfile" && test -f "$keepfile"
                then
                        rm -f "$keepfile"
                fi
        ' 0

        keepfile=
        while read sha1 remote_name
        do
          case "$sha1" in
          failed)
                  echo >&2 "Fetch failure: $remote"
                  exit 1 ;;
          # special line coming from index-pack with the pack name
          pack)
                  continue ;;
          keep)
                  keepfile="$GIT_OBJECT_DIRECTORY/pack/pack-$remote_name.keep"
                  continue ;;
          esac
          found=
          single_force=
          for ref in $refs
          do
              case "$ref" in
              +$remote_name:*)
                  single_force=t
                  not_for_merge=
                  found="$ref"
                  break ;;
              .+$remote_name:*)
                  single_force=t
                  not_for_merge=t
                  found="$ref"
                  break ;;
              .$remote_name:*)
                  not_for_merge=t
                  found="$ref"
                  break ;;
              $remote_name:*)
                  not_for_merge=
                  found="$ref"
                  break ;;
              esac
          done
          local_name=$(expr "z$found" : 'z[^:]*:\(.*\)')
          append_fetch_head "$sha1" "$remote" \
                  "$remote_name" "$remote_nick" "$local_name" \
                  "$not_for_merge" || exit
        done
      )
    ) || exit

}

fetch_dumb () {
  reflist="$1"
  refs=
  rref=

  for ref in $reflist
  do
      refs="$refs$LF$ref"

      # These are relative path from $GIT_DIR, typically starting at refs/
      # but may be HEAD
      if expr "z$ref" : 'z\.' >/dev/null
      then
          not_for_merge=t
          ref=$(expr "z$ref" : 'z\.\(.*\)')
      else
          not_for_merge=
      fi
      if expr "z$ref" : 'z+' >/dev/null
      then
          single_force=t
          ref=$(expr "z$ref" : 'z+\(.*\)')
      else
          single_force=
      fi
      remote_name=$(expr "z$ref" : 'z\([^:]*\):')
      local_name=$(expr "z$ref" : 'z[^:]*:\(.*\)')

      rref="$rref$LF$remote_name"

      # There are transports that can fetch only one head at a time...
      case "$remote" in
      http://* | https://* | ftp://*)
          test -n "$shallow_depth" &&
                die "shallow clone with http not supported"
          proto=`expr "$remote" : '\([^:]*\):'`
          if [ -n "$GIT_SSL_NO_VERIFY" ]; then
              curl_extra_args="-k"
          fi
          if [ -n "$GIT_CURL_FTP_NO_EPSV" -o \
                "`git-config --bool http.noEPSV`" = true ]; then
              noepsv_opt="--disable-epsv"
          fi

          # Find $remote_name from ls-remote output.
          head=$(
                IFS='   '
                echo "$ls_remote_result" |
                while read sha1 name
                do
                        test "z$name" = "z$remote_name" || continue
                        echo "$sha1"
                        break
                done
          )
          expr "z$head" : "z$_x40\$" >/dev/null ||
                die "No such ref $remote_name at $remote"
          echo >&2 "Fetching $remote_name from $remote using $proto"
          git-http-fetch -v -a "$head" "$remote/" || exit
          ;;
      rsync://*)
          test -n "$shallow_depth" &&
                die "shallow clone with rsync not supported"
          TMP_HEAD="$GIT_DIR/TMP_HEAD"
          rsync -L -q "$remote/$remote_name" "$TMP_HEAD" || exit 1
          head=$(git-rev-parse --verify TMP_HEAD)
          rm -f "$TMP_HEAD"
          test "$rsync_slurped_objects" || {
              rsync -av --ignore-existing --exclude info \
                  "$remote/objects/" "$GIT_OBJECT_DIRECTORY/" || exit

              # Look at objects/info/alternates for rsync -- http will
              # support it natively and git native ones will do it on
              # the remote end.  Not having that file is not a crime.
              rsync -q "$remote/objects/info/alternates" \
                  "$GIT_DIR/TMP_ALT" 2>/dev/null ||
                  rm -f "$GIT_DIR/TMP_ALT"
              if test -f "$GIT_DIR/TMP_ALT"
              then
                  resolve_alternates "$remote" <"$GIT_DIR/TMP_ALT" |
                  while read alt
                  do
                      case "$alt" in 'bad alternate: '*) die "$alt";; esac
                      echo >&2 "Getting alternate: $alt"
                      rsync -av --ignore-existing --exclude info \
                      "$alt" "$GIT_OBJECT_DIRECTORY/" || exit
                  done
                  rm -f "$GIT_DIR/TMP_ALT"
              fi
              rsync_slurped_objects=t
          }
          ;;
      esac

      append_fetch_head "$head" "$remote" \
          "$remote_name" "$remote_nick" "$local_name" "$not_for_merge" || exit

  done

}

fetch_main () {
        case "$remote" in
        http://* | https://* | ftp://* | rsync://* )
                fetch_dumb "$@"
                ;;
        *)
                fetch_native "$@"
                ;;
        esac
}

fetch_main "$reflist" || exit

# automated tag following
case "$no_tags$tags" in
'')
        case "$reflist" in
        *:refs/*)
                # effective only when we are following remote branch
                # using local tracking branch.
                taglist=$(IFS=' ' &&
                echo "$ls_remote_result" |
                git-show-ref --exclude-existing=refs/tags/ |
                while read sha1 name
                do
                        git-cat-file -t "$sha1" >/dev/null 2>&1 || continue
                        echo >&2 "Auto-following $name"
                        echo ".${name}:${name}"
                done)
        esac
        case "$taglist" in
        '') ;;
        ?*)
                # do not deepen a shallow tree when following tags
                shallow_depth=
                fetch_main "$taglist" || exit ;;
        esac
esac

# If the original head was empty (i.e. no "master" yet), or
# if we were told not to worry, we do not have to check.
case "$orig_head" in
'')
        ;;
?*)
        curr_head=$(git-rev-parse --verify HEAD 2>/dev/null)
        if test "$curr_head" != "$orig_head"
        then
            git-update-ref \
                        -m "$GIT_REFLOG_ACTION: Undoing incorrectly fetched HEAD." \
                        HEAD "$orig_head"
                die "Cannot fetch into the current branch."
        fi
        ;;
esac