1.0

README.md

@@ -1,2 +1,83 @@
 # XNGNotificationProxy
-wip
+
+English | [中文](https://www.jianshu.com/p/3fe728c4d7a3)
+
+XNGNotificationProxy is a replacement of custom NSNotification.
+
+## A common scenario of NSNotification in use
+
+You followed a user in VC_U, so the follow buttons in VC_A and VC_B should update state.
+
+```
+// VC_U.m
+
+[[NSNotificationCenter defaultCenter] postNotificationName:@"UserDidFollowUser"
+                                                    object:nil
+                                                  userInfo:@{@"isFollowed": @(YES), @"userID": @(123456)}];
+```
+```
+// VC_A.m or VC_B.m
+
+[[NSNotificationCenter defaultCenter] addObserverForName:@"UserDidFollowUser"
+                                                  object:nil
+                                                   queue:nil
+                                              usingBlock:^(NSNotification * _Nonnull note) {
+                                                  BOOL isFollowed = [note.userInfo[@"isFollowed"] boolValue];
+                                                  NSNumber *userID = note.userInfo[@"userID"];
+                                              }];
+```
+There are a lot of magic strings. We may define some global constant strings to solve this, but we can never know what parameters are in the userInfo intuitively.
+
+## Use XNGNotificationProxy
+
+You need create a category for XNGNotificationProxy that conforms a custom protocol first.
+```
+// XNGNotificationProxy+Protocol.h
+
+@protocol UserActionProtocol <NSObject>
+@optional
+- (void)userDidFollow:(BOOL)isFollowed userID:(NSNumber *)userID;
+@end
+
+
+@interface XNGNotificationProxy (Protocol) <UserActionProtocol>
+@end
+```
+then
+```
+// VC_U.m
+
+[[XNGNotificationProxy sharedProxy] userDidFollow:YES userID:@(123456)];
+```
+```
+// VC_A.m
+
+@interface VC_A () <UserActionProtocol>
+@end
+
+// -viewDidLoad or somewhere else
+[[XNGNotificationProxy sharedProxy] registerProtocol:@protocol(UserActionProtocol) forObject:self];
+
+// 
+- (void)userDidFollow:(BOOL)isFollowed userID:(NSNumber *)userID {
+    // do something
+}
+```
+
+## Requirements
+
+iOS 7.0 or later.
+
+## Installation
+
+There are two ways to use XNGNotificationProxy in your project:
+- using CocoaPods
+- drag `XNGNotificationProxy` folder into your project
+
+## Licenses
+
+XNGNotificationProxy is released under the MIT license. See [LICENSE](https://github.com/xuning0/XNGNotificationProxy/blob/master/LICENSE) for details.
+
+
+
+

XNGNotificationProxy.podspec

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+Pod::Spec.new do |s|
+  s.name         = "XNGNotificationProxy"
+  s.version      = "1.0"
+  s.summary      = "A replacement of custom NSNotification using NSProxy."
+  s.homepage     = "https://github.com/xuning0/XNGNotificationProxy"
+  s.license      = "MIT"
+  s.author       = { "XuNing" => "xuning0@outlook.com" }
+  s.platform     = :ios, "7.0"
+  s.source       = { :git => "https://github.com/xuning0/XNGNotificationProxy.git", :tag => "#{s.version}" }
+  s.requires_arc = true
+
+  s.source_files = "XNGNotificationProxy/*.{h,m}"
+end

XNGNotificationProxy/XNGNotificationProxy.h

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+//
+//  XNGNotificationProxy.h
+//  XNGNotificationProxy
+//
+//  Created by XuNing on 2019/1/22.
+//  Copyright © 2019 xuning. All rights reserved.
+//
+
+#import <Foundation/Foundation.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface XNGNotificationProxy : NSProxy
+
++ (instancetype)sharedProxy;
+
+- (void)registerProtocol:(Protocol *)protocol forObject:(id)obj;
+
+@end
+
+NS_ASSUME_NONNULL_END

XNGNotificationProxy/XNGNotificationProxy.m

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+//
+//  XNGNotificationProxy.m
+//  XNGNotificationProxy
+//
+//  Created by XuNing on 2019/1/22.
+//  Copyright © 2019 xuning. All rights reserved.
+//
+
+#import "XNGNotificationProxy.h"
+#import <objc/runtime.h>
+
+@interface XNGNotificationProxy ()
+// { method1: [obj1, obj2], method2: [obj3, obj4], ... }
+@property(nonatomic, strong) NSMutableDictionary<NSString *, NSHashTable *> *methodDictionary;
+// for self.methodDictionary thread safty
+@property(nonatomic, strong) dispatch_queue_t modificationQueue;
+@end
+
+@implementation XNGNotificationProxy
+
++ (instancetype)sharedProxy {
+    static XNGNotificationProxy *proxy;
+    static dispatch_once_t onceToken;
+    dispatch_once(&onceToken, ^{
+        proxy = [XNGNotificationProxy alloc];
+        proxy.methodDictionary = [NSMutableDictionary dictionary];
+        proxy.modificationQueue = dispatch_queue_create("com.notificationProxy.modification", DISPATCH_QUEUE_SERIAL);
+    });
+    return proxy;
+}
+
+- (void)registerProtocol:(Protocol *)protocol forObject:(id)obj {
+    NSParameterAssert(protocol);
+    NSParameterAssert(obj);
+    NSAssert([obj conformsToProtocol:protocol], @"object %@ does not conform to protocol: %@", obj, protocol);
+    NSArray *methodNames = [XNGNotificationProxy getAllMethodNamesInProtocol:protocol];
+    for (NSString *name in methodNames) {
+        dispatch_sync(self.modificationQueue, ^{
+            NSHashTable *hashTable = self.methodDictionary[name];
+            if (!hashTable.anyObject) {
+                hashTable = [NSHashTable weakObjectsHashTable];
+            }
+            [hashTable addObject:obj];
+            self.methodDictionary[name] = hashTable;
+        });
+    }
+}
+
+#pragma mark - Override Method
+- (NSMethodSignature *)methodSignatureForSelector:(SEL)sel {
+    for (id obj in [self objectsInHashTableForSelector:sel]) {
+        if ([obj respondsToSelector:sel]) {
+            return [obj methodSignatureForSelector:sel];
+        }
+    }
+    // if this method returns nil, a selector not found exception is raised.
+    // https://github.com/facebookarchive/AsyncDisplayKit/pull/1562
+    return [NSMethodSignature signatureWithObjCTypes:"@^v^c"];
+}
+
+- (void)forwardInvocation:(NSInvocation *)invocation {
+    for (id obj in [self objectsInHashTableForSelector:invocation.selector]) {
+        if ([obj respondsToSelector:invocation.selector]) {
+            [invocation invokeWithTarget:obj];
+        }
+    }
+}
+
+#pragma mark - Private Method
+- (NSArray *)objectsInHashTableForSelector:(SEL)sel {
+    __block NSArray *objects;
+    dispatch_sync(self.modificationQueue, ^{
+        objects = self.methodDictionary[NSStringFromSelector(sel)].allObjects;
+    });
+    return objects;
+}
+
++ (void)enumerateMethodsInProtocol:(Protocol *)protocol
+                        isRequired:(BOOL)isRequired
+                        usingBlock:(void (^)(struct objc_method_description method))block {
+    unsigned int methodsCountInProtocol = 0;
+    struct objc_method_description *methods = protocol_copyMethodDescriptionList(protocol, isRequired, YES, &methodsCountInProtocol);
+    for (unsigned int i = 0; i < methodsCountInProtocol; i++) {
+        struct objc_method_description method = methods[i];
+        !block ?: block(method);
+    }
+    free(methods);
+}
+
++ (NSArray *)getAllMethodNamesInProtocol:(Protocol *)protocol {
+    NSMutableArray *methodNames = [NSMutableArray array];
+    [self enumerateMethodsInProtocol:protocol
+                          isRequired:YES
+                          usingBlock:^(struct objc_method_description method) {
+                              [methodNames addObject:NSStringFromSelector(method.name)];
+                          }];
+    [self enumerateMethodsInProtocol:protocol
+                          isRequired:NO
+                          usingBlock:^(struct objc_method_description method) {
+                              [methodNames addObject:NSStringFromSelector(method.name)];
+                          }];
+    return [methodNames copy];
+}
+
+@end

XNGNotificationProxyDemo/Podfile

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+platform :ios, '9.0'
+
+target 'XNGNotificationProxyDemo' do
+
+  use_frameworks!
+
+  pod 'XNGNotificationProxy', :path => '..'
+
+end

XNGNotificationProxyDemo/Podfile.lock

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+PODS:
+  - XNGNotificationProxy (1.0)
+
+DEPENDENCIES:
+  - XNGNotificationProxy (from `..`)
+
+EXTERNAL SOURCES:
+  XNGNotificationProxy:
+    :path: ".."
+
+SPEC CHECKSUMS:
+  XNGNotificationProxy: 746998e2e0d0b55f6ad825197b6ec12aebe11ceb
+
+PODFILE CHECKSUM: 2a37536700d33c5101136eb7474edbd371fa61c1
+
+COCOAPODS: 1.5.3