Merge "PackageCacher: cache key for block-device APEX" into main

     * Returns the cache key for a specified {@code packageFile} and {@code flags}.

     */

    private String getCacheKey(File packageFile, int flags) {

        StringBuilder sb = new StringBuilder(packageFile.getName());

        String name = packageFile.getName();

        String absPath = packageFile.getAbsolutePath();

        // In case the package is an APEX which is from a device-mapper block

        // device created by apexd, the filename (dm-NN) can be different on

        // each boot. Hence, we use the device-mapper name instead, which is

        // stable across reboots.

        if (absPath.startsWith("/dev/block/dm-")) {

            try {

                name = IoUtils.readFileAsString("/sys/block/" + name + "/dm/name").trim();

                // The device name represents the file. No need to append the hash of the full path.

                absPath = null;

            } catch (IOException e) {

                Slog.w("Error while reading device name of " + name, e);

            }

        }

        StringBuilder sb = new StringBuilder(name);

        sb.append('-');

        sb.append(flags);

        if (absPath != null) {

            sb.append('-');

        sb.append(packageFile.getAbsolutePath().hashCode());

            sb.append(absPath.hashCode());

        }

        return sb.toString();

    }