Reading obfuscated objects

Sometimes a patch holds an object and needs a value buried inside it. Say a feed post's video link is post.attributes.videos[0].getUrl(), and every class on that path has a meaningless name. A binding describes the path once, by structure. Any patch can then use it and get null-checked code that walks the path.

val post = bind("post") {
    fromField("feedPostField") {
        owner(onPostClicked.owner)
        nearestObjectReadBeforeString("post_clicked")
    }
    string("videoUrl") {
        member("attributes")
        listGetter("videos") {
            rankBy("callers followed by cast") { callSitesFollowedByCast(VIDEO) }
        }
        first()
        cast(VIDEO)
        callInterface(VIDEO, "getUrl", "()Ljava/lang/String;")
    }
}

• The source (fromField, fromMethod, or fromClass) finds the class the path starts from.
• Members (string, objectValue, intValue, context, bind) are named paths. Each step reads a field, calls a method, casts, or takes a list element.

Use it in a code block:

onPostClicked.before {
    val url = post.member("videoUrl", thisObject.field(post.sourceField))
    whenNotNull(url) { call(Downloads.offer, url) }
}

If any step on the path is null, the result is null (or zero), so check it with whenNotNull.

The reference lists every source and step.

Next: Shipping your own code.