1 files changed, 54 insertions, 0 deletions
diff --git a/src/shared/settings/KeySequence.ts b/src/shared/settings/KeySequence.ts
new file mode 100644
index 0000000..4955583
--- /dev/null
+++ b/src/shared/settings/KeySequence.ts
@@ -0,0 +1,54 @@
+import Key from '../../shared/settings/Key';
+
+export default class KeySequence {
+  constructor(
+    public readonly keys: Key[],
+  ) {
+  }
+
+  push(key: Key): number {
+    return this.keys.push(key);
+  }
+
+  length(): number {
+    return this.keys.length;
+  }
+
+  startsWith(o: KeySequence): boolean {
+    if (this.keys.length < o.keys.length) {
+      return false;
+    }
+    for (let i = 0; i < o.keys.length; ++i) {
+      if (!this.keys[i].equals(o.keys[i])) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  static fromMapKeys(keys: string): KeySequence {
+    const fromMapKeysRecursive = (
+      remaining: string, mappedKeys: Key[],
+    ): Key[] => {
+      if (remaining.length === 0) {
+        return mappedKeys;
+      }
+
+      let nextPos = 1;
+      if (remaining.startsWith('<')) {
+        let ltPos = remaining.indexOf('>');
+        if (ltPos > 0) {
+          nextPos = ltPos + 1;
+        }
+      }
+
+      return fromMapKeysRecursive(
+        remaining.slice(nextPos),
+        mappedKeys.concat([Key.fromMapKey(remaining.slice(0, nextPos))])
+      );
+    };
+
+    let data = fromMapKeysRecursive(keys, []);
+    return new KeySequence(data);
+  }
+}