Pre-compile filter rules instead of re-lowercasing per article per emission

ArticleListScreen calls evaluate() once per visible article against the
same rule set, re-run on essentially any read-state change to any
article in the list. With a couple hundred articles and a handful of
rules, calling pattern.lowercase() inside the old per-article evaluate()
was thousands of redundant String allocations of the same small set
of strings.

1 files changed, 2 insertions, 1 deletions

diff --git a/app/src/main/java/org/terst/feedreader/ui/ArticleListScreen.kt b/app/src/main/java/org/terst/feedreader/ui/ArticleListScreen.kt
index a852288..6f2db12 100644
--- a/app/src/main/java/org/terst/feedreader/ui/ArticleListScreen.kt
+++ b/app/src/main/java/org/terst/feedreader/ui/ArticleListScreen.kt
@@ -72,7 +72,8 @@ fun ArticleListScreen(
     }
     val visibleArticles by remember(feedId) {
         combine(articleFlow, db.filterRuleDao().observeAll()) { articles, rules ->
-            articles.map { it to FilterRuleEngine.evaluate(it, rules) }
+            val compiledRules = FilterRuleEngine.compile(rules)
+            articles.map { it to FilterRuleEngine.evaluate(it, compiledRules) }
                 .filter { (_, result) -> result != FilterResult.MUTED }
         }
     }.collectAsState(initial = emptyList())