[gdb/contrib] Add spellcheck.sh

I came across a table containing common misspellings [1], and wrote a script to
detect and correct these misspellings.

The table also contains entries that have alternatives, like this:
...
addres->address, adders
...
and for those the script prints a TODO instead.

The script downloads the webpage containing the table, extracts the table and
caches it in .git/wikipedia-common-misspellings.txt to prevent downloading it
over and over again.

Example usage:
...
$ gdb/contrib/spellcheck.sh gdb*
...

ChangeLog files are silently skipped.

Checked with shellcheck.

Tested on x86_64-linux, by running it on the gdb* dirs on doing a build and
test run.

The results of running it are in the two following patches.

Reviewed-By: Andrew Burgess <aburgess@redhat.com>
Approved-By: Tom Tromey <tom@tromey.com>
[1] https://en.wikipedia.org/wiki/Wikipedia:Lists_of_common_misspellings/For_machines

diff --git a/gdb/contrib/spellcheck.sh b/gdb/contrib/spellcheck.sh
new file mode 100755 (executable)
index 0000000..e7db621
--- /dev/null
+++ b/gdb/contrib/spellcheck.sh
@@ -0,0 +1,287 @@
+#!/bin/bash
+
+# Copyright (C) 2024 Free Software Foundation, Inc.
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+# Script to auto-correct common spelling mistakes.
+#
+# Example usage:
+# $ ./gdb/contrib/spellcheck.sh gdb*
+
+scriptdir=$(cd "$(dirname "$0")" || exit; pwd -P)
+
+url=https://en.wikipedia.org/wiki/Wikipedia:Lists_of_common_misspellings/For_machines
+cache_dir=$scriptdir/../../.git
+cache_file=wikipedia-common-misspellings.txt
+dictionary=$cache_dir/$cache_file
+
+# Separators: space, slash, tab.
+grep_separator=" |/|   "
+sed_separator=" \|/\|\t"
+
+usage ()
+{
+    echo "usage: $(basename "$0") <file|dir>+"
+}
+
+make_absolute ()
+{
+    local arg
+    arg="$1"
+
+    case "$arg" in
+       /*)
+       ;;
+       *)
+           arg=$(pwd -P)/"$arg"
+           ;;
+    esac
+
+    echo "$arg"
+}
+
+parse_args ()
+{
+    local files
+    files=$(mktemp)
+    trap 'rm -f "$files"' EXIT
+
+    if [ $# -eq -0 ]; then
+       usage
+       exit 1
+    fi
+
+    local arg
+    for arg in "$@"; do
+       if [ -f "$arg" ]; then
+           arg=$(make_absolute "$arg")
+           readlink -e "$arg" \
+                    >> "$files"
+       elif [ -d "$arg" ]; then
+           arg=$(make_absolute "$arg")
+           local f
+           find "$arg" -type f -exec readlink -e {} \; \
+                >> "$files"
+       else
+           echo "Not a file or directory: $arg"
+           exit 1
+       fi
+    done
+
+    mapfile -t unique_files \
+           < <(sort -u "$files" \
+                   | grep -v ChangeLog)
+
+    rm -f "$files"
+    trap "" EXIT
+}
+
+get_dictionary ()
+{
+    if [ -f "$dictionary" ]; then
+       return
+    fi
+
+    local webpage
+    webpage=$(mktemp)
+    trap 'rm -f "$webpage"' EXIT
+
+    # Download web page containing table.
+    wget $url -O "$webpage"
+
+    # Extract table from web page.
+    awk '/<pre>/,/<\/pre>/' "$webpage" \
+       | sed 's/<pre>//;s/<\/pre>//' \
+       | grep -E -v "^$" \
+              > "$dictionary"
+
+    rm -f "$webpage"
+    trap "" EXIT
+}
+
+parse_dictionary ()
+{
+    # Parse dictionary.
+    mapfile -t words \
+           < <(awk -F '->' '{print $1}' "$dictionary")
+    mapfile -t replacements \
+           < <(awk -F '->' '{print $2}' "$dictionary")
+}
+
+find_files_matching_words ()
+{
+    local pat
+    pat=""
+    for word in "${words[@]}"; do
+       if [ "$pat" = "" ]; then
+           pat="$word"
+       else
+           pat="$pat|$word"
+       fi
+    done
+    pat="($pat)"
+
+    local sep
+    sep=$grep_separator
+
+    pat="(^|$sep)$pat($sep|$)"
+
+    grep -E \
+       -l \
+       "$pat" \
+       "$@"
+}
+
+find_files_matching_word ()
+{
+    local pat
+    pat="$1"
+    shift
+
+    local sep
+    sep=$grep_separator
+
+    pat="(^|$sep)$pat($sep|$)"
+
+    grep -E \
+       -l \
+       "$pat" \
+       "$@"
+}
+
+replace_word_in_file ()
+{
+    local word
+    word="$1"
+
+    local replacement
+    replacement="$2"
+
+    local file
+    file="$3"
+
+    local sep
+    sep=$sed_separator
+
+    # Save separator.
+    sep="\($sep\)"
+
+    local repl1 repl2 repl3
+
+    repl1="s%$sep$word$sep%\1$replacement\2%g"
+
+    repl2="s%^$word$sep%$replacement\1%"
+
+    repl3="s%$sep$word$%\1$replacement%"
+
+    sed -i \
+       "$repl1;$repl2;$repl3" \
+       "$file"
+}
+
+replace_word_in_files ()
+{
+    local word
+    word="$1"
+
+    local replacement
+    replacement="$2"
+
+    shift 2
+
+    local id
+    id="$word -> $replacement"
+
+    # Reduce set of files for sed to operate on.
+    local files_matching_word
+    declare -a files_matching_word
+    mapfile -t files_matching_word \
+           < <(find_files_matching_word "$word" "$@")
+
+    if [ ${#files_matching_word[@]} -eq 0 ]; then
+       return
+    fi
+
+    if echo "$replacement"| grep -q ","; then
+       echo "TODO: $id"
+       return
+    fi
+
+    declare -A md5sums
+
+    local changed f before after
+    changed=false
+    for f in "${files_matching_word[@]}"; do
+       if [ "${md5sums[$f]}" = "" ]; then
+           md5sums[$f]=$(md5sum "$f")
+       fi
+
+       before="${md5sums[$f]}"
+
+       replace_word_in_file \
+           "$word" \
+           "$replacement" \
+           "$f"
+
+       after=$(md5sum "$f")
+
+       if [ "$after" != "$before" ]; then
+           md5sums[$f]="$after"
+           changed=true
+       fi
+    done
+
+    if $changed; then
+       echo "$id"
+    fi
+
+    find_files_matching_word "$word" "${files_matching_word[@]}" \
+       | awk "{ printf \"TODO: $id: replacement failed: %s\n\", \$0}"
+}
+
+main ()
+{
+    declare -a unique_files
+    parse_args "$@"
+
+    get_dictionary
+
+    declare -a words
+    declare -a replacements
+    parse_dictionary
+
+    # Reduce set of files for sed to operate on.
+    local files_matching_words
+    declare -a files_matching_words
+    mapfile -t files_matching_words \
+           < <(find_files_matching_words "${unique_files[@]}")
+
+    if [ ${#files_matching_words[@]} -eq 0 ]; then
+       return
+    fi
+
+    local i word replacement
+    i=0
+    for word in "${words[@]}"; do
+       replacement=${replacements[$i]}
+       i=$((i + 1))
+
+       replace_word_in_files \
+           "$word" \
+           "$replacement" \
+           "${files_matching_words[@]}"
+    done
+}
+
+main "$@"