From 83b9d5c682b21d88133f24da0f94dd56bd79e687 Mon Sep 17 00:00:00 2001
From: 单军华
Date: Thu, 19 Jul 2018 13:38:55 +0800
Subject: [PATCH] change
---
screendisplay/screendisplay/Classes/Category/ThirdCategory/NullSafe.m | 134 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 134 insertions(+), 0 deletions(-)
diff --git a/screendisplay/screendisplay/Classes/Category/ThirdCategory/NullSafe.m b/screendisplay/screendisplay/Classes/Category/ThirdCategory/NullSafe.m
new file mode 100755
index 0000000..302568c
--- /dev/null
+++ b/screendisplay/screendisplay/Classes/Category/ThirdCategory/NullSafe.m
@@ -0,0 +1,134 @@
+//
+// NullSafe.m
+//
+// Version 1.2.2
+//
+// Created by Nick Lockwood on 19/12/2012.
+// Copyright 2012 Charcoal Design
+//
+// Distributed under the permissive zlib License
+// Get the latest version from here:
+//
+// https://github.com/nicklockwood/NullSafe
+//
+// This software is provided 'as-is', without any express or implied
+// warranty. In no event will the authors be held liable for any damages
+// arising from the use of this software.
+//
+// Permission is granted to anyone to use this software for any purpose,
+// including commercial applications, and to alter it and redistribute it
+// freely, subject to the following restrictions:
+//
+// 1. The origin of this software must not be misrepresented; you must not
+// claim that you wrote the original software. If you use this software
+// in a product, an acknowledgment in the product documentation would be
+// appreciated but is not required.
+//
+// 2. Altered source versions must be plainly marked as such, and must not be
+// misrepresented as being the original software.
+//
+// 3. This notice may not be removed or altered from any source distribution.
+//
+
+#import <objc/runtime.h>
+#import <Foundation/Foundation.h>
+
+
+#ifndef NULLSAFE_ENABLED
+#define NULLSAFE_ENABLED 1
+#endif
+
+
+#pragma GCC diagnostic ignored "-Wgnu-conditional-omitted-operand"
+
+
+@implementation NSNull (NullSafe)
+
+#if NULLSAFE_ENABLED
+
+- (NSMethodSignature *)methodSignatureForSelector:(SEL)selector
+{
+ @synchronized([self class])
+ {
+ //look up method signature
+ NSMethodSignature *signature = [super methodSignatureForSelector:selector];
+ if (!signature)
+ {
+ //not supported by NSNull, search other classes
+ static NSMutableSet *classList = nil;
+ static NSMutableDictionary *signatureCache = nil;
+ if (signatureCache == nil)
+ {
+ classList = [[NSMutableSet alloc] init];
+ signatureCache = [[NSMutableDictionary alloc] init];
+
+ //get class list
+ int numClasses = objc_getClassList(NULL, 0);
+ Class *classes = (Class *)malloc(sizeof(Class) * (unsigned long)numClasses);
+ numClasses = objc_getClassList(classes, numClasses);
+
+ //add to list for checking
+ NSMutableSet *excluded = [NSMutableSet set];
+ for (int i = 0; i < numClasses; i++)
+ {
+ //determine if class has a superclass
+ Class someClass = classes[i];
+ Class superclass = class_getSuperclass(someClass);
+ while (superclass)
+ {
+ if (superclass == [NSObject class])
+ {
+ [classList addObject:someClass];
+ break;
+ }
+ [excluded addObject:NSStringFromClass(superclass)];
+ superclass = class_getSuperclass(superclass);
+ }
+ }
+
+ //remove all classes that have subclasses
+ for (Class someClass in excluded)
+ {
+ [classList removeObject:someClass];
+ }
+
+ //free class list
+ free(classes);
+ }
+
+ //check implementation cache first
+ NSString *selectorString = NSStringFromSelector(selector);
+ signature = signatureCache[selectorString];
+ if (!signature)
+ {
+ //find implementation
+ for (Class someClass in classList)
+ {
+ if ([someClass instancesRespondToSelector:selector])
+ {
+ signature = [someClass instanceMethodSignatureForSelector:selector];
+ break;
+ }
+ }
+
+ //cache for next time
+ signatureCache[selectorString] = signature ?: [NSNull null];
+ }
+ else if ([signature isKindOfClass:[NSNull class]])
+ {
+ signature = nil;
+ }
+ }
+ return signature;
+ }
+}
+
+- (void)forwardInvocation:(NSInvocation *)invocation
+{
+ invocation.target = nil;
+ [invocation invoke];
+}
+
+#endif
+
+@end
--
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