From c372df97f631470048b98e1849d3ccd1a9db8e5f Mon Sep 17 00:00:00 2001
From: Lucy Phipps <landfillbaby@outlook.com>
Date: Sat, 21 Nov 2020 18:33:58 +0000
Subject: [PATCH] vastly reduce database size by not storing $PREFIX

also escape filenames for sqlite, realpath -sm
---
 update-whatprovides-db.sh |  4 +++-
 whatprovides              | 28 ++++++++++++++++++++++++----
 2 files changed, 27 insertions(+), 5 deletions(-)

diff --git a/update-whatprovides-db.sh b/update-whatprovides-db.sh
index cab3d52..e5975ed 100755
--- a/update-whatprovides-db.sh
+++ b/update-whatprovides-db.sh
@@ -7,7 +7,9 @@
 set -e -u
 
 list_files() {
-	dpkg-deb -c "${1}" | grep -o "/data/data/com.termux/.*" | sed -E 's@(.*) ->..*@\1@g'
+	dpkg-deb -c "${1}" | grep -o "/data/data/com\.termux/files/.\+" \
+		| sed -E 's@(.*) ->..*@\1@g;s@/$@@g' \
+		| xargs -rd\\n realpath -sm --relative-base=$TERMUX_PREFIX --
 }
 
 write_sql_script() {
diff --git a/whatprovides b/whatprovides
index 1107534..6ce116b 100755
--- a/whatprovides
+++ b/whatprovides
@@ -118,12 +118,32 @@ if ${REVERSE_MODE}; then
 
 	sqlite3 "${DB_PATH}" \
 		"SELECT owned_file FROM 'whatprovides' WHERE package_name == '${1}' ORDER BY owned_file" \
-		| awk "{ print \"${1}: \"\$0 }"
+		| awk "NR == 1 { print \"${1}: /.\\n${1}: /data\\n${1}: /data/data\\n${1}: /data/data/com.termux\\n${1}: /data/data/com.termux/files\\n${1}: ${PREFIX}\" } { print \"${1}: ${PREFIX}/\"\$0 }"
 else
-	FILE="$(realpath "$1")"
+	NEWPREFIX=
+	FILE="$(realpath -sm "$1")"
+
+	if [[ "${PREFIX}/" = "${FILE}/"* || "${FILE}" = / ]]; then
+		# FILE is (((great...)grand)parent of) PREFIX, including root
+		if [ "${FILE}" = / ]; then
+			FILE=/.
+		fi
+
+		sqlite3 "${DB_PATH}" \
+			"SELECT DISTINCT package_name FROM 'whatprovides' ORDER BY package_name" \
+			| awk "{ print \$0\": ${FILE}\" }"
+		exit 0
+	fi
+
+	if [[ "${FILE}" = "${PREFIX}/"* ]]; then
+		# FILE is in PREFIX
+		FILE="${FILE##${PREFIX}/}"
+		NEWPREFIX="${PREFIX}/"
+	fi # else FILE is entirely separate from PREFIX (unlikely to be in DB)
+
 	if ! sqlite3 "${DB_PATH}" \
-		"SELECT package_name FROM 'whatprovides' WHERE owned_file == '$FILE' ORDER BY package_name" \
-		| awk "{ print \$0\": $FILE\" } END {if (NR == 0) exit 1 }"
+		"SELECT package_name FROM 'whatprovides' WHERE owned_file == '${FILE//\'/\'\'}' ORDER BY package_name" \
+		| awk "{ print \$0\": ${NEWPREFIX}${FILE}\" } END { if (NR == 0) exit 1 }"
 	then
 		{
 			echo