From b53430871a4efe017c118e5eaa7aa30e3e51f92f Mon Sep 17 00:00:00 2001
From: Danny Lin <danny@kdrag0n.dev>
Date: Sun, 28 Nov 2021 19:49:35 -0800
Subject: [PATCH] config: filters: Add generic filter processing

---
 src/config/filters.ts | 72 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)
 create mode 100644 src/config/filters.ts

diff --git a/src/config/filters.ts b/src/config/filters.ts
new file mode 100644
index 0000000..40854cf
--- /dev/null
+++ b/src/config/filters.ts
@@ -0,0 +1,72 @@
+import { SysPartition } from '../util/partitions'
+
+export enum FilterMode {
+  Include = 'include',
+  Exclude = 'exclude',
+}
+
+export interface SerializedFilters {
+  mode: FilterMode
+
+  match: string[]
+  prefix: string[]
+  suffix: string[]
+  regex: string[]
+}
+
+export interface Filters {
+  // true = inclusion list, false = exclusion list
+  include: boolean
+
+  match: Set<string>
+  prefix: string[]
+  suffix: string[]
+  regex: RegExp[]
+}
+
+export type PartFilters = Record<SysPartition, Filters>
+
+export function parseFilters(src: SerializedFilters) {
+  return {
+    include: src.mode == FilterMode.Include,
+
+    match: new Set(src.match),
+    prefix: src.prefix,
+    suffix: src.suffix,
+    regex: src.regex.map(pat => new RegExp(pat)),
+  } as Filters
+}
+
+function _matchFilters(filters: Filters, value: string) {
+  return filters.match.has(value) ||
+    filters.prefix.find(prefix => value.startsWith(prefix)) != undefined ||
+    filters.suffix.find(suffix => value.endsWith(suffix)) != undefined ||
+    filters.regex.find(regex => value.match(regex)) != null
+}
+
+export function filterValue(filters: Filters, value: string) {
+  return filters.include ?
+    _matchFilters(filters, value) :
+    !_matchFilters(filters, value)
+}
+
+export function filterValues(filters: Filters, values: string[]) {
+  return values.filter(value => filterValue(filters, value))
+}
+
+// Map, in-place
+export function filterKeys<Value>(filters: Filters, map: Map<string, Value>) {
+  for (let key of map.keys()) {
+    if (!filterValue(filters, key)) {
+      map.delete(key)
+    }
+  }
+
+  return map
+}
+
+// Map, copy
+export function filterKeysCopy<Value>(filters: Filters, map: Map<string, Value>) {
+  return new Map(Array.from(map.entries())
+    .filter(([key]) => filterValue(filters, key)))
+}