1 files changed, 28 insertions, 0 deletions
diff --git a/devtools/shared/network-observer/WildcardToRegexp.sys.mjs b/devtools/shared/network-observer/WildcardToRegexp.sys.mjs
new file mode 100644
index 0000000000..4c495fdd78
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+++ b/devtools/shared/network-observer/WildcardToRegexp.sys.mjs
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+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/**
+ * Converts a URL-like string which might include the `*` character as a wildcard
+ * to a regular expression. They are used to match against actual URLs for the
+ * request blocking feature from DevTools.
+ *
+ * The returned regular expression is case insensitive.
+ *
+ * @param {string} url
+ *     A URL-like string which can contain one or several `*` as wildcard
+ *     characters.
+ * @return {RegExp}
+ *     A regular expression which can be used to match URLs compatible with the
+ *     provided url "template".
+ */
+export function wildcardToRegExp(url) {
+  return new RegExp(url.split("*").map(regExpEscape).join(".*"), "i");
+}
+
+/**
+ * Escapes all special RegExp characters in the given string.
+ */
+const regExpEscape = s => {
+  return s.replace(/[|\\{}()[\]^$+*?.]/g, "\\$&");
+};