From 252ae33500e8faabb67caeea4a93ea7e50ae98fc Mon Sep 17 00:00:00 2001
From: onevcat <onevcat@gmail.com>
Date: Wed, 21 Dec 2016 16:37:30 +0900
Subject: [PATCH] Throw an error instead of fatal error

---
 APNGKit/Disassembler.swift | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/APNGKit/Disassembler.swift b/APNGKit/Disassembler.swift
index eabaebf..089a077 100644
--- a/APNGKit/Disassembler.swift
+++ b/APNGKit/Disassembler.swift
@@ -75,6 +75,7 @@ public enum DisassemblerError: Error {
     case pngStructureFailure
     case pngInternalError
     case fileSizeExceeded
+    case invalidAPNGMeta
 }
 
 /**
@@ -358,7 +359,7 @@ class Disassembler {
             frames.append(frame)
         }
         guard let apngMeta = apngMeta else {
-            fatalError("The APNG meta should exists.")
+            throw DisassemblerError.invalidAPNGMeta
         }
         return (frames, apngMeta)
     }
@@ -367,7 +368,9 @@ class Disassembler {
         try prepare()
         clean()
         
-        guard let apngMeta = apngMeta else { fatalError("The apng meta should exists") }
+        guard let apngMeta = apngMeta else {
+            throw DisassemblerError.invalidAPNGMeta
+        }
         return apngMeta
     }