Method filter

app/src/main/java/eu/faircode/email/Adguard.java:75–340

(Context context, Uri uri)

    ));

    @Nullable
    public static Uri filter(Context context, Uri uri) {
        if (uri.isOpaque())
            return null;

        String host = uri.getHost();
        if (TextUtils.isEmpty(host))
            return null;

        File file = getFile(context);
        if (!file.exists())
            return null;

        List<String> removes = new ArrayList<>();
        List<String> importants = new ArrayList<>();
        List<String> excepts = new ArrayList<>();

        try (BufferedReader br = new BufferedReader(new InputStreamReader(new FileInputStream(file)))) {
            String line;
            while ((line = br.readLine()) != null) {
                // https://adguard.com/kb/general/ad-filtering/create-own-filters/#comments
                if (TextUtils.isEmpty(line) || line.startsWith("!"))
                    continue;

                // rule = ["@@"] pattern [ "$" modifiers ]
                // modifiers = [modifier0, modifier1[, ...[, modifierN]]]

                int dollar = line.indexOf('$');
                while (dollar > 0 && line.charAt(dollar - 1) == '\\')
                    dollar = line.indexOf('$', dollar + 1);
                if (dollar < 0) {
                    // ||https-filtering-check.adtidy.org^
                    if (!line.contains("##"))
                        Log.w("Adguard command missing line=" + line);
                    continue;
                }

                String pattern = line.substring(0, dollar)
                        .replace("\\$", "$");
                String rest = line.substring(dollar + 1)
                        .replace("\\$", "$");

                int start = 0;
                List<String> modifiers = new ArrayList<>();
                while (start < rest.length()) {
                    int comma = rest.indexOf(',', start);
                    while (comma > 0 && rest.charAt(comma - 1) == '\\')
                        comma = rest.indexOf(',', comma + 1);
                    int end = (comma < 0 ? rest.length() : comma);
                    modifiers.add(rest.substring(start, end)
                            .replace("\\,", ","));
                    start = (comma < 0 ? end : end + 1);
                }

                String remove = null;
                boolean important = false;
                boolean matches = true;
                List<String> contents = new ArrayList<>();