Support for hard wrap points in header_wrap

Adding empty arguments to header_wrap causes the function to insert hard
line breaks, allowing certain features in the header to be emphasized on
their own lines regardless of automatic wrapping. These hard breaks are
ignored when $(tput lines) is less than 24, to avoid adding excessive
vertical noise on constrained displays.

Author: ahesford

90zfsbootmenu/zfsbootmenu-lib.sh

@@ -112,63 +112,93 @@ csv_cat() {
 # returns: nothing
 
 header_wrap() {
-  local tokens footer
+  local hardbreak tokens tok footer nlines
 
-  # Nothing to print if there is no header
-  [ $# -gt 0 ] || return
+  # Pick a wrap width if none was specified
+  [ -n "$wrap_width" ] || wrap_width="$(( $( tput cols ) - 4 ))"
 
-  # Encode spaces in tokens so wrap won't break them
+  nlines="$( tput lines 2>/dev/null )" || nlines=0
+
+  # Processing is done line-by-line
   while [ $# -gt 0 ]; do
-    tokens+=( "${1// /_}" )
-    shift
-  done
+    hardbreak=0
+    tokens=()
+
+    # Process up to the first empty string, which is a hard break
+    while [ $# -gt 0 ]; do
+      tok="${1// /_}"
+      shift
+
+      if [ -n "${tok}" ]; then
+        tokens+=( "${tok}" )
+      elif [ "$nlines" -ge 24 ]; then
+        # Hard wrap on empty tokens only with sufficient space
+        hardbreak=1
+        break
+      fi
+    done
 
-  # Pick a wrap width if none was specified
-  [ -n "$wrap_width" ] || wrap_width="$(( $( tput cols ) - 4 ))"
+    # Print the header if there were tokens
+    if [ "${#tokens[@]}" -gt 0 ]; then
+      # Only try to wrap if the width is long enough
+      if [ "${wrap_width}" -gt 0 ]; then
+        footer="$( echo -n -e "${tokens[@]}" | fold -s -w "${wrap_width}" )"
+      else
+        footer="$( echo -n -e "${tokens[@]}" )"
+      fi
+
+      # Add some color for emphasis
+      footer="${footer//\[/\\033\[0;32m\[}"
+      footer="${footer//\]/\]\\033\[0m}"
+
+      echo -n -e "${footer//_/ }"
+    fi
 
-  footer="$( echo -n -e "${tokens[@]}" | fold -s -w "${wrap_width}" )"
-  footer="${footer//\[/\\033\[0;32m\[}"
-  footer="${footer//\]/\]\\033\[0m}"
-  echo -n -e "${footer//_/ }"
+    # Add a hard break if an empty token was provided
+    if [ "${hardbreak}" -ne 0 ]; then
+      echo ""
+    fi
+  done
 }
 
 # arg1: Path to file with detected boot environments, 1 per line
-# prints: key pressed, boot environment
-# returns: 130 on error, 0 otherwise
+# prints: key pressed, boot environment on successful selection
+# returns: 0 on successful selection, 1 if Esc was pressed, 130 if BE list is missing
 
 draw_be() {
-  local env selected ret header
+  local env selected header
 
   env="${1}"
 
   zdebug "using environment file: ${env}"
 
-  test -f "${env}" || return 130
+  [ -f "${env}" ] || return 130
 
-  header="$( header_wrap "[ENTER] boot" "[ALT+K] kernels" \
-    "[ALT+S] snapshots" "[ALT+D] set bootfs" "[ALT+E] edit kcl" \
-    "[ALT+P] pool status" "[ALT+R] recovery shell" "[ALT+C] chroot" "[ALT+H] help")"
+  header="$( header_wrap "[ENTER] boot" "[ESC] refresh view" "" \
+    "[ALT+E] edit kcl" "[ALT+K] kernels" "[ALT+D] set bootfs" "[ALT+S] snapshots" "" \
+    "[ALT+C] chroot" "[ALT+R] recovery shell" "[ALT+P] pool status" "[ALT+H] help" )"
 
-  selected="$( ${FUZZYSEL} -0 --prompt "BE > " \
-    --expect=alt-k,alt-d,alt-s,alt-c,alt-r,alt-p,alt-w,alt-e \
-    --header="${header}" --preview-window="up:${PREVIEW_HEIGHT}" \
-    --preview="/libexec/zfsbootmenu-preview ${BASE} {} ${BOOTFS}" < "${env}" )"
-  ret=$?
+  if ! selected="$( ${FUZZYSEL} -0 --prompt "BE > " \
+      --expect=alt-k,alt-d,alt-s,alt-c,alt-r,alt-p,alt-w,alt-e \
+      --header="${header}" --preview-window="up:${PREVIEW_HEIGHT}" \
+      --preview="/libexec/zfsbootmenu-preview ${BASE} {} ${BOOTFS}" < "${env}" )"; then
+    return 1
+  fi
 
   # shellcheck disable=SC2119
   selected="$( csv_cat <<< "${selected}" )"
   echo "${selected}"
   zdebug "selected: ${selected}"
 
-  return ${ret}
+  return 0
 }
 
 # arg1: ZFS filesystem name
 # prints: bootfs, kernel, initramfs
 # returns: 130 on error, 0 otherwise
 
 draw_kernel() {
-  local benv selected ret header _kernels
+  local benv selected header _kernels
 
   benv="${1}"
   _kernels="${BASE}/${benv}/kernels"
@@ -177,50 +207,55 @@ draw_kernel() {
 
   test -f "${_kernels}" || return 130
 
-  header="$( header_wrap "[ENTER] boot" "[ALT+D] set default" "[ESC] back" "[ALT+H] help" )"
+  header="$( header_wrap \
+    "[ENTER] boot" "[ESC] back" "" "[ALT+D] set default" "[ALT+H] help" )"
 
-  selected="$( HELP_SECTION=KERNEL ${FUZZYSEL} --prompt "${benv} > " \
-    --tac --expect=alt-d --with-nth=2 --header="${header}" \
-    --preview-window="up:${PREVIEW_HEIGHT}" \
-    --preview="/libexec/zfsbootmenu-preview ${BASE} ${benv} ${BOOTFS}" < "${_kernels}" )"
-  ret=$?
+  if ! selected="$( HELP_SECTION=KERNEL ${FUZZYSEL} --prompt "${benv} > " \
+      --tac --expect=alt-d --with-nth=2 --header="${header}" \
+      --preview-window="up:${PREVIEW_HEIGHT}" \
+      --preview="/libexec/zfsbootmenu-preview \
+      ${BASE} ${benv} ${BOOTFS}" < "${_kernels}" )"; then
+    return 1
+  fi
 
   # shellcheck disable=SC2119
   selected="$( csv_cat <<< "${selected}" )"
   echo "${selected}"
   zdebug "selected: ${selected}"
 
-  return ${ret}
+  return 0
 }
 
 # arg1: ZFS filesystem name
 # prints: selected snapshot
 # returns: 130 on error, 0 otherwise
 
 draw_snapshots() {
-  local benv selected ret header
+  local benv selected header
 
   benv="${1}"
 
   zdebug "using boot environment: ${benv}"
 
-  header="$( header_wrap "[ENTER] duplicate" "[ALT+X] clone and promote" \
-    "[ALT+C] clone only" "[ALT+D] show diff" "[ESC] back" "[ALT+H] help" )"
+  header="$( header_wrap \
+    "[ENTER] duplicate" "[ESC] back" "" \
+    "[ALT+D] show diff" "[ALT+X] clone and promote" "[ALT+C] clone only" "[ALT+H] help" )"
 
-  selected="$( zfs list -t snapshot -H -o name "${benv}" |
+  if ! selected="$( zfs list -t snapshot -H -o name "${benv}" |
       HELP_SECTION=SNAPSHOT ${FUZZYSEL} --prompt "Snapshot > " \
         --tac --expect=alt-x,alt-c,alt-d \
         --preview="/libexec/zfsbootmenu-preview ${BASE} ${benv} ${BOOTFS}" \
         --preview-window="up:${PREVIEW_HEIGHT}" \
-        --header="${header}" )"
-  ret=$?
+        --header="${header}" )"; then
+    return 1
+  fi
 
   # shellcheck disable=SC2119
   selected="$( csv_cat <<< "${selected}" )"
   echo "${selected}"
   zdebug "selected: ${selected}"
 
-  return ${ret}
+  return 0
 }
 
 # arg1: ZFS snapshot
@@ -271,25 +306,25 @@ draw_diff() {
 # returns: 130 on error, 0 otherwise
 
 draw_pool_status() {
-  local selected ret header hdr_width
+  local selected header hdr_width
 
   # Wrap to half width to avoid the preview window
   hdr_width="$(( ( $( tput cols ) / 2 ) - 4 ))"
   header="$( wrap_width="$hdr_width" header_wrap \
-    "[ALT+R] rewind checkpoint" "[ESC] back" "[ALT+H] help" )"
+    "[ESC] back" "" "[ALT+R] rewind checkpoint" "" "[ALT+H] help" )"
 
-  selected="$( zpool list -H -o name |
-    HELP_SECTION=POOL ${FUZZYSEL} --prompt "Pool > " --tac \
-      --expect=alt-r --preview="zpool status -v {}" --header="${header}"
-  )"
-  ret=$?
+  if ! selected="$( zpool list -H -o name |
+      HELP_SECTION=POOL ${FUZZYSEL} --prompt "Pool > " --tac \
+      --expect=alt-r --preview="zpool status -v {}" --header="${header}" )"; then
+    return 1
+  fi
 
   # shellcheck disable=SC2119
   selected="$( csv_cat <<< "${selected}" )"
   echo "${selected}"
   zdebug "selected: ${selected}"
 
-  return ${ret}
+  return 0
 }
 
 # arg1: bootfs kernel initramfs