From e73e7ec8112236a76ced37aafc9805beb6bf054c Mon Sep 17 00:00:00 2001
From: Tim Otten <totten@civicrm.org>
Date: Tue, 26 Jun 2018 16:08:50 -0700
Subject: [PATCH] (dev/core#174) CRM_Utils_Date - Add helpers for handling
 PSR-16 TTL's

---
 CRM/Utils/Date.php | 52 ++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 52 insertions(+)

diff --git a/CRM/Utils/Date.php b/CRM/Utils/Date.php
index 3d4570d7e1..74aa2e35ca 100644
--- a/CRM/Utils/Date.php
+++ b/CRM/Utils/Date.php
@@ -695,6 +695,58 @@ class CRM_Utils_Date {
     return TRUE;
   }
 
+  /**
+   * Translate a TTL to a concrete expiration time.
+   *
+   * @param NULL|int|DateInterval $ttl
+   * @param int $default
+   *   The value to use if $ttl is not specified (NULL).
+   * @return int
+   *   Timestamp (seconds since epoch).
+   * @throws \CRM_Utils_Cache_InvalidArgumentException
+   */
+  public static function convertCacheTtlToExpires($ttl, $default) {
+    if ($ttl === NULL) {
+      $ttl = $default;
+    }
+
+    if (is_int($ttl)) {
+      return time() + $ttl;
+    }
+    elseif ($ttl instanceof DateInterval) {
+      return date_add(new DateTime(), $ttl)->getTimestamp();
+    }
+    else {
+      throw new CRM_Utils_Cache_InvalidArgumentException("Invalid cache TTL");
+    }
+  }
+
+  /**
+   * Normalize a TTL.
+   *
+   * @param NULL|int|DateInterval $ttl
+   * @param int $default
+   *   The value to use if $ttl is not specified (NULL).
+   * @return int
+   *   Seconds until expiration.
+   * @throws \CRM_Utils_Cache_InvalidArgumentException
+   */
+  public static function convertCacheTtl($ttl, $default) {
+    if ($ttl === NULL) {
+      return $default;
+    }
+    elseif (is_int($ttl)) {
+      return $ttl;
+    }
+    elseif ($ttl instanceof DateInterval) {
+      return date_add(new DateTime(), $ttl)->getTimestamp() - time();
+    }
+    else {
+      throw new CRM_Utils_Cache_InvalidArgumentException("Invalid cache TTL");
+    }
+  }
+
+
   /**
    * @param null $timeStamp
    *
-- 
2.25.1