ThemesAndStylesLintFunctions2.kt

internal fun Attr.belongsToItem() = ownerElement.nodeName == "item"

internal fun Element.belongsToStyle() = parentNode.nodeName == "style"

internal fun Element.belongsToThemeOrThemeOverlay() = belongsToStyle()
        && parentNode.attributes.getNamedItem("name").nodeValue.startsWith("Theme")

/**
 * Looks for VALUE in a <style> resource
 * e.g. <item name="attrName">VALUE</item>
 * else returns null
 */
internal fun Element.findValueOfItemWithName(attrName: String): String? {
    if (nodeName != "style") throw IllegalArgumentException("Expected <style> element but found: $nodeName")
    return getChildren(this)
            .firstOrNull { element -> element.nodeName == "item" && element.getAttribute("name") == attrName }
            ?.firstChild
            ?.nodeValue
}