clipmenu-spmenu/clipmenud

#!/bin/bash

: "${CM_ONESHOT=0}"
: "${CM_OWN_CLIPBOARD=1}"
: "${CM_DEBUG=0}"
: "${CM_DIR="${XDG_RUNTIME_DIR-"${TMPDIR-/tmp}"}"}"
: "${CM_MAX_CLIPS=1000}"
: "${CM_SELECTIONS=clipboard primary}"

major_version=4
cache_dir=$CM_DIR/clipmenu.$major_version.$USER/
cache_file=$cache_dir/line_cache
lock_file=$cache_dir/lock
lock_timeout=2
has_clipnotify=0

# This comes from the environment, so we rely on word splitting.
# shellcheck disable=SC2206
cm_selections=( $CM_SELECTIONS )


xsel_log=/dev/null
for file in /proc/self/fd/2 /dev/stderr; do
    [[ -f "$file" ]] || continue
    # In Linux, it's not possible to write to a socket represented by a file
    # (for example, /dev/stderr or /proc/self/fd/2). See issue #54.
    [[ -f "$(readlink "$file")" ]] || continue
    xsel_log="$file"
    break
done

_xsel() {
    timeout 1 xsel --logfile "$xsel_log" "$@"
}

get_first_line() {
    # Args:
    # - $1, the file or data
    # - $2, optional, the line length limit

    data=${1?}
    line_length_limit=${2-300}

    # We look for the first line matching regex /./ here because we want the
    # first line that can provide reasonable context to the user. That is, if
    # you have 5 leading lines of whitespace, displaying " (6 lines)" is much
    # less useful than displaying "foo (6 lines)", where "foo" is the first
    # line in the entry with actionable context.
    awk -v limit="$line_length_limit" '
        BEGIN { printed = 0; }

        printed == 0 && NF {
            $0 = substr($0, 0, limit);
            printf("%s", $0);
            printed = 1;
        }

        END {
            if (NR > 1) {
                print " (" NR " lines)";
            } else {
                printf("\n");
            }
        }' <<< "$data"
}

debug() {
    if (( CM_DEBUG )); then
        printf '%s\n' "$@" >&2
    fi
}

element_in() {
    local item element
    item="$1"
    for element in "${@:2}"; do
        if [[ "$item" == "$element" ]]; then
            return 0
        fi
    done
    return 1
}

if [[ $1 == --help ]] || [[ $1 == -h ]]; then
    cat << 'EOF'
clipmenud is the daemon that collects and caches what's on the clipboard.
when you want to select a clip.

Environment variables:

- $CM_ONESHOT: run once immediately, do not loop (default: 0)
- $CM_DEBUG: turn on debugging output (default: 0)
- $CM_OWN_CLIPBOARD: take ownership of the clipboard (default: 1)
- $CM_MAX_CLIPS: maximum number of clips to store, 0 for inf (default: 1000)
- $CM_DIR: specify the base directory to store the cache dir in (default: $XDG_RUNTIME_DIR, $TMPDIR, or /tmp)
- $CM_SELECTIONS: space separated list of the selections to manage (default: "clipboard primary")
EOF
    exit 0
fi


# It's ok that this only applies to the final directory.
# shellcheck disable=SC2174
mkdir -p -m0700 "$cache_dir"

command -v clipnotify >/dev/null 2>&1 && has_clipnotify=1

if ! (( has_clipnotify )); then
    echo "WARN: Consider installing clipnotify for better performance." >&2
    echo "WARN: See https://github.com/cdown/clipnotify." >&2
fi

exec {lock_fd}> "$lock_file"

sleep_cmd=(sleep "${CM_SLEEP:-0.5}")

while true; do
    # We need to take ownership synchronously before we run `clipnotify` as
    # otherwise we could enter an infinite loop.
    if (( CM_OWN_CLIPBOARD )) && element_in clipboard "${cm_selections[@]}"; then
        # Take ownership of the clipboard, in case the original application
        # is unable to serve the clipboard request (due to being suspended,
        # etc).
        #
        # Primary is excluded from the change of ownership as applications
        # sometimes act up if clipboard focus is taken away from them --
        # for example, urxvt will unhilight text, which is undesirable.
        #
        # We need to check if the clipboard is empty to mitigate #34.
        data=$(_xsel -o --clipboard; printf x)
        [[ $data != x ]] && _xsel -i --clipboard <<< "${data%x}"
    fi

    if ! (( CM_ONESHOT )); then
        if (( has_clipnotify )); then
            # Fall back to polling if clipnotify fails
            clipnotify || "${sleep_cmd[@]}"
        else
            # Use old polling method
            "${sleep_cmd[@]}"
        fi
    fi

    if ! flock -x -w "$lock_timeout" "$lock_fd"; then
        printf 'ERROR: %s\n' 'Timed out waiting for lock' >&2
        exit 1
    fi

    for selection in "${cm_selections[@]}"; do
        data=$(_xsel -o --"$selection"; printf x)

        debug "Data before stripping: $data"

        # We add and remove the x so that trailing newlines are not stripped.
        # Otherwise, they would be stripped by the very nature of how POSIX
        # defines command substitution.
        data=${data%x}

        debug "Data after stripping: $data"

        if [[ $data != *[^[:space:]]* ]]; then
            debug "Skipping as clipboard is only blank"
            continue
        fi

        first_line=$(get_first_line "$data")

        debug "New clipboard entry on $selection selection: \"$first_line\""

        filename="$cache_dir/$(cksum <<< "$first_line")"
        debug "Writing $data to $filename"
        printf '%s' "$data" > "$filename"

        debug "Writing $first_line to $cache_file"
        printf '%s\n' "$first_line" >> "$cache_file"

        if (( CM_MAX_CLIPS )); then
            mapfile -t to_remove < <(
                head -n -"$CM_MAX_CLIPS" "$cache_file" |
                    while read -r line; do cksum <<< "$line"; done
            )
            num_to_remove="${#to_remove[@]}"
            if (( num_to_remove )); then
                debug "Removing $num_to_remove old clips"
                rm -- "${to_remove[@]/#/"$cache_dir/"}"
                trunc_tmp=$(mktemp)
                tail -n "$CM_MAX_CLIPS" "$cache_file" | uniq > "$trunc_tmp"
                mv -- "$trunc_tmp" "$cache_file"
            fi
        fi
    done

    flock -u "$lock_fd"

    if (( CM_ONESHOT )); then
        debug 'Oneshot mode enabled, exiting'
        break
    fi
done