From da34103dacaddc76a31c16a3887c04081edf6954 Mon Sep 17 00:00:00 2001
From: perlatus <git@perlat.us>
Date: Wed, 9 May 2018 22:39:11 -0400
Subject: [PATCH] Add getFileIfCached method to CacheManager

---
 lib/flutter_cache_manager.dart | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/lib/flutter_cache_manager.dart b/lib/flutter_cache_manager.dart
index 551d9943..30745621 100644
--- a/lib/flutter_cache_manager.dart
+++ b/lib/flutter_cache_manager.dart
@@ -183,6 +183,26 @@ class CacheManager {
     }
   }
 
+  /// Get the file from the cache if previously loaded from [url]. If the file
+  /// is not cached, Future returns null.
+  Future<File> getFileIfCached(String url) async {
+    var cacheObject = _cacheData[url];
+    if (cacheObject == null) {
+      return null;
+    }
+
+    return await synchronized(cacheObject.lock, () async {
+      cacheObject.touch();
+      var filePath = await cacheObject.getFilePath();
+      if (filePath == null) {
+        return null;
+      }
+
+      File cachedFile = new File(filePath);
+      return cachedFile.existsSync() ? cachedFile : null;
+    });
+  }
+
   ///Get the file from the cache or online. Depending on availability and age
   Future<File> getFile(String url, {Map<String, String> headers}) async {
     String log = "[Flutter Cache Manager] Loading $url";