Add scripts for automating copyright notices update

* maint/update_copyright_years.awk: New file.
* maint/update_copyright_years.sh: Likewise.

Co-authored-by: Elvira Khabirova <lineprinter0@gmail.com>

diff --git a/maint/update_copyright_years.awk b/maint/update_copyright_years.awk
new file mode 100644 (file)
index 0000000..ee356c3
--- /dev/null
+++ b/maint/update_copyright_years.awk
@@ -0,0 +1,45 @@
+# External variables:
+#   COMMENT_MARKER    - marks beginning of the comment on the line
+#   COMMENT_MARKER_RE - the same as previous, but in form usable
+#                       as a part of a regular expression
+#   COPYRIGHT_MARKER  - text inside comment
+#   COPYRIGHT_NOTICE  - copyright notice text to insert
+
+BEGIN {
+       # States:
+       #   0 - before finding copyright notice
+       #   1 - in copyright notice or its continuation
+       #   2 - right after the end of copyright notice
+       #   3 - copyright notice added
+       state = 0
+       prefix = " "
+
+       comment_re = "^" COMMENT_MARKER_RE
+       copyright_re = comment_re "([[:space:]]*)" COPYRIGHT_MARKER
+       copyright_cont_re = copyright_re
+}
+
+state <= 1 && match($0, copyright_re, a) {
+       state = 1
+       prefix = a[1]
+       # set copyright notice continuation
+       copyright_cont_re = comment_re a[1] "[[:space:]]"
+}
+
+# this is neither copyright notice nor its continuation
+state == 1 && ($0 !~ copyright_re) && ($0 !~ copyright_cont_re) {
+       state = 2
+}
+
+state == 2 {
+       print COMMENT_MARKER prefix COPYRIGHT_NOTICE
+       state = 3
+}
+
+{
+       print
+}
+
+END {
+       exit 3 - state
+}

diff --git a/maint/update_copyright_years.sh b/maint/update_copyright_years.sh
new file mode 100755 (executable)
index 0000000..7444245
--- /dev/null
+++ b/maint/update_copyright_years.sh
@@ -0,0 +1,202 @@
+#!/bin/sh
+#
+# Update copyright notices for source files.
+#
+# Copyright (c) 2017 The strace developers.
+# All rights reserved.
+#
+# Redistribution and use in source and binary forms, with or without
+# modification, are permitted provided that the following conditions
+# are met:
+# 1. Redistributions of source code must retain the above copyright
+#    notice, this list of conditions and the following disclaimer.
+# 2. Redistributions in binary form must reproduce the above copyright
+#    notice, this list of conditions and the following disclaimer in the
+#    documentation and/or other materials provided with the distribution.
+# 3. The name of the author may not be used to endorse or promote products
+#    derived from this software without specific prior written permission.
+#
+# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
+# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
+# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
+# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+: ${COPYRIGHT_NOTICE='The strace developers.'}
+: ${COPYRIGHT_MARKER='Copyright'}
+: ${COPYRIGHT_PREFIX="${COPYRIGHT_MARKER} (c)"}
+: ${VERBOSE=1}
+: ${CALL_GIT_ADD=0}
+
+# These files are only imported into strace and not changed.
+# Remove them from the list once they have been changed.
+IGNORED_FILES="git-set-file-times
+gitlog-to-changelog
+${ADDITIONAL_IGNORED_FILES}"
+
+log()   { [ "$VERBOSE" -ge 1 ] && printf '%s\n' "$*"; }
+debug() { [ "$VERBOSE" -ge 2 ] && printf '%s\n' "$*"; }
+
+print_help()
+{
+       cat <<EOF
+Usage: update_copyright_notices [-v]* [-q]* [-a] [-h] [FILES]
+
+If no files provided, process all files in current directory, recursively.
+Only git-tracked files are processed.
+
+Script implements hard-coded logic for extracting comments in files:
+  ' *'    *.c, *.h (as part of multiline /* ... */ comment)
+  '.\"'   *.[1-8] (man pages)
+  '#'     Everything else
+
+Options:
+  -a  Invoke git add for the changed files.
+  -v  Increase verbosity.
+  -q  Decrease verbosity.
+  -h  Show this help.
+  -b  Overwrite beginning year too on update of existing notice.
+
+Environment:
+  COPYRIGHT_NOTICE  Copyright ownership string.
+  COPYRIGHT_MARKER  What strings are considered copyright strings.
+  COPYTIGHT_PREFIX  Part of copyright string before the year interval.
+  VERBOSE           Verbosity level.
+  CALL_GIT_ADD      Whether to invoke 'git add' on processed files.
+EOF
+}
+
+# $1 - file name
+# $2 - return version suitable for using in regular expressions
+get_comment_prefix()
+{
+       case "$1" in
+       *.[ch])
+               printf '%s' ' *'
+               ;;
+       *.[1-8])
+               printf '%s' '.\"'
+               ;;
+       *)
+               printf '%s' '#'
+               ;;
+       esac
+}
+
+# $1 - file
+process_file()
+{
+       local f p r span p_quoted r_quoted year_re start_note
+       local last_commit_year first_commit_year
+       local copyright_year copyright_year_raw copyright_notice
+       local existing_notice_re existing_notice_year
+
+       f="$1"
+
+       p=$(get_comment_prefix "$f")
+       r=$(printf '%s' "$p" | sed 's/[].*&^$[\/]/\\&/g')
+
+       year_re="[12][0-9][0-9][0-9]"
+       copyright_year_raw=$(sed -n \
+               "/^${r}  *${COPYRIGHT_MARKER}"'/s/.*[- ]\('"${year_re}"'\)\( .*\)\?$/\1/p' \
+                       < "$f")
+
+       if [ -z "$copyright_year_raw" ]; then
+               debug "Copyright notices haven't been found, skipping: $f"
+               continue
+       fi
+
+       last_commit_year=$(git log -n1 --format=format:%ad \
+               --date=format:%Y -- "$f")
+       first_commit_year=$(git log --reverse --format=format:%ad \
+               --date=format:%Y -- "$f" | head -n 1)
+       copyright_year=$(printf '%s' "$copyright_year_raw" |
+               sort -r -n | head -n 1)
+       start_note='from git log'
+
+       existing_notice_re="^\(${r}  *${COPYRIGHT_MARKER}.* \)\(\(${year_re}\)\([-, ]*${year_re}\)*\)\( ${COPYRIGHT_NOTICE}\)$"
+       existing_notice_year=$(sed -n \
+               "/${existing_notice_re}/s//\\3/p" "$f")
+       # assume copyright notice is still relevant
+       if [ "$last_commit_year" = "$copyright_year" ]; then
+               debug "Does not need update, skipping: $f"
+               continue
+       else
+               debug "Needs update ('$copyright_year' != '$last_commit_year'): $f"
+       fi
+
+       # avoid gaps not covered by copyright
+       [ "$first_commit_year" -lt "$copyright_year" ] || {
+               start_note='from last copyright year'
+               first_commit_year="$copyright_year"
+       }
+
+       # if there is existing notice, its starting year takes precedence
+       if [ -n "$existing_notice_year" ]; then
+               start_note='from existing copyright notice'
+               first_commit_year="$existing_notice_year"
+       fi
+
+       if [ "$first_commit_year" = "$last_commit_year" ]; then
+               span="$last_commit_year"
+       else
+               span="$first_commit_year-$last_commit_year"
+       fi
+
+       copyright_notice="${COPYRIGHT_PREFIX} ${span} ${COPYRIGHT_NOTICE}"
+       p_quoted="$(printf '%s' "$p" | sed 's/\\/\\\\/g')" \
+       r_quoted="$(printf '%s' "$r" | sed 's/\\/\\\\/g')" \
+
+       if [ -n "$existing_notice_year" ]; then
+               # update existing notice, avoid touching starting date
+               sed -i "/${existing_notice_re}/s//\\1${span} ${COPYRIGHT_NOTICE}/" "$f" &&
+                       log "Updated copyright notice in $f (start year $start_note)"
+       else
+               awk \
+                       -v COMMENT_MARKER="$p_quoted" \
+                       -v COMMENT_MARKER_RE="$r_quoted" \
+                       -v COPYRIGHT_NOTICE="$copyright_notice" \
+                       -v COPYRIGHT_MARKER="$COPYRIGHT_MARKER" \
+                       -f $(dirname "$0")/update_copyright_years.awk \
+                       "$f" > "$f.out" && {
+                               cat "$f.out" > "$f"
+                               log "Added copyright notice to $f (start year $start_note)"
+                       } || debug "No changes performed (exit code $?), skipping: $f"
+
+                       rm -f "$f.out"
+       fi
+
+       [ "$CALL_GIT_ADD" = 0 ] || git add "$f"
+}
+
+while [ -n "$1" ]; do
+       case "$1" in
+       "-v")
+               VERBOSE=$(($VERBOSE + 1))
+               ;;
+       "-q")
+               VERBOSE=$(($VERBOSE - 1))
+               ;;
+       "-h")
+               print_help
+               exit 1
+               ;;
+       "-a")
+               CALL_GIT_ADD=1
+               ;;
+       *)
+               break
+               ;;
+       esac
+
+       shift
+done
+
+git ls-files -- "$@" | grep -vFx "$IGNORED_FILES" | while read f; do
+       process_file "$f"
+done