1 ## Compare symlink to target:

     2 #

     3 #   link_check $lnk $tgt && do_link $lnk $tgt || ...

     4 #

     5 # Tests if the symlink exists, and the target matches.

     6 # Fails if the symlink needs updating.

     7 function link_check {

     8     local out="$1"

     9     local lnk="$2"

    10 

    11     [ -e "$out" ] || return 1

    12 

    13     [ -L "$out" ] || fail "$out: is not a link"

    14 

    15     [ "$(readlink "$out")" == "$lnk" ] || return 1

    16 

    17     return 0

    18 }

    19 

    20 ## Update symlink to point to target:

    21 #

    22 #   do_link $lnk $tgt

    23 #

    24 function link_apply {

    25     local out="$1"

    26     local lnk="$2"

    27 

    28     cmd ln -srf "$lnk" "$out"

    29 

    30     [ -e "$out" ] || fail "$out: given target does not exist: $lnk"

    31 }

    32 

    33 # Create symlink if not exists.

    34 function apply_link {

    35     local out="$1"

    36     local lnk="$2"

    37 

    38     if link_check "$out" "$lnk"; then

    39         log_skip "$out: not changed: $lnk"

    40     elif [ "$APPLY" = 0 ]; then

    41         log_noop "$out: skip link: $tgt"

    42     else

    43         log_apply "$out: $tgt..."

    44 

    45         link_apply "$out" "$lnk"

    46     fi

    47 }