本来想看一下AsyncSocket的源码，但是发现每次读英文注释也是很麻烦的，不如直接把它翻译一下。而且在边看边翻译的过程中，会一直在想作者为什么会这么写，顺便还可以学习一下高手编程的良好习惯 和思路。
1 #import <Foundation/Foundation.h> 2 3 @class AsyncSocket;//async异步的 synchro同步 4 @class AsyncReadPacket; 5 @class AsyncWritePacket; 6 7 //extern来说可以理解为扩展吧是这样的是从一个类扩展到另一个类中的 8 extern NSString *const AsyncSocketException;//Exception:意外 9 extern NSString *const AsyncSocketErrorDomin;//errorDomin :错误域名 10 11 enum AsyncSocketError//socket错误 12 { 13 AsynsocketCFSocketError = kCFSocketError,// kCFSocketError is from CFSocketError enum; 14 AsyncSocketNoError = 0,//never used 15 AsyncSocketCanceledError,//onSocketWillConnect :return NO 16 AsyncSocketReadTimmeoutError, 17 AsyncSocketWritrTimeoutError 18 }; 19 typedef enum AsyncSocketError AsyncSocketError;//typedef 20 21 @interface NSObject (AsyncSocketDelegate)//类目,虽然看上去像是代理方法，但是作者把它们写成了NSObject类的扩展方法 因此实际编程中包含该.h文件的所有类都可以直接使用这些方法 22 23 24 /** 25 * In the event of an error, the socket is closed. 26 * You may call "unreadData" during this call-back to get the last bit of data off the socket. 27 * When connecting, this delegate method may be called 28 * before"onSocket:didAcceptNewSocket:" or "onSocket:didConnectToHost:". 29 **/ 30 //发生错误 socket将要断开连接 31 -(void) onSocket:(AsyncSocket *)sock willDisconnectWithError:(NSError *)err; 32 33 /** 34 * Called when a socket accepts a connection. Another socket is spawned to handle it. The new socket will have 35 * the same delegate and will call "onSocket:didConnectToHost:port:". 36 **/ 37 //在socket断开连接时将被执行（不管有没有发生错误）。如果你想在一个socket断开连接后release它，do so here。在“onSocket：willDisconnectWithError中那样做是不安全的 38 -(void)onSocketDidDisconnect:(AsyncSocket *)socket; 39 40 /** 41 * Called when a socket accepts a connection. Another socket is spawned to handle it. The new socket will have 42 * the same delegate and will call "onSocket:didConnectToHost:port:". 43 **/ 44 //called when 一个socket接受了一个连接（connection），会产生另一个新的socket去处理这个连接（好像是服务器中用的那个，sock是监听（listen）socket，接受到连接后会产生新的socket去处理连接）。新产生的socket将存在相同的代理，而且会call "onSocket:didConnectToHost:port:". 45 -(void)onSocket:(AsyncSocket *)sock didAcceptNewSocket:(AsyncSocket *)newSocket; 46 47 /** 48 * Called when a new socket is spawned to handle a connection. This method should return the run-loop of the 49 * thread on which the new socket and its delegate should operate. If omitted, [NSRunLoop currentRunLoop] is used. 50 **/ 51 //omitted：省略，遗漏 52 //called when一个新socket被产生去处理一个连接。这个方法将会返回这个新socket和它的代理将要操作的线程（thread）的运行回路（runloop） 53 -(NSRunLoop *)onSocket:(AsyncSocket *)sock wantsRunLoopForNewSocket:(AsyncSocket *)newSocket; 54 55 /** 56 * Called when a socket is about to connect. This method should return YES to continue, or NO to abort. 57 * If aborted, will result in AsyncSocketCanceledError. 58 * 59 * If the connectToHost:onPort:error: method was called, the delegate will be able to access and configure the 60 * CFReadStream and CFWriteStream as desired prior to connection. 61 * 62 * If the connectToAddress:error: method was called, the delegate will be able to access and configure the 63 * CFSocket and CFSocketNativeHandle (BSD socket) as desired prior to connection. You will be able to access and 64 * configure the CFReadStream and CFWriteStream in the onSocket:didConnectToHost:port: method. 65 **/ 66 //abort:使流产，使中止 prior：优先的，在。。。之前 configure：配置，设定 67 //be about to :是指将要做某事，或是发生某事，是指可以预见的，并且确定要发生的 68 //在一个socket将要连接时被调用。要继续连接，则让该方法返回YES，要中止连接，则让该方法返回NO。如果中止（返回NO）将会导致AsyncSocketCanceledError。 69 //如果connectToHost:onPort:error: 方法在这之前被调用过，这个代理方法可以进入到之前想要进行的连接，并配置CFReadStream和CFWriteStream 70 -(BOOL)onSocketWillConnect:(AsyncSocket *)socket; 71 72 /** 73 * Called when a socket connects and is ready for reading and writing. 74 * The host parameter will be an IP address, not a DNS name. 75 **/ 76 //called when 一个socket已经连接，并且已经准备读写。host参数是IP地址，而不是DNS域名 77 - (void)onSocket:(AsyncSocket *)sock didConnectToHost:(NSString *)host port:(UInt16)port; 78 79 /** 80 * Called when a socket has completed reading the requested data into memory. 81 * Not called if there is an error. 82 **/ 83 //当一个socket已经把数据读入内存中时被调用。如果发生错误则不被调用 84 - (void)onSocket:(AsyncSocket *)sock didReadData:(NSData *)data withTag:(long)tag; 85 86 /** 87 * Called when a socket has read in data, but has not yet completed the read. 88 * This would occur if using readToData: or readToLength: methods. 89 * It may be used to for things such as updating progress bars. 90 **/ 91 //当一个socket已经读入数据但是还没有读完的时候被调用。在使用readToData: 或者 readToLength:方法的时候可能会产生这种情况。它在某些情况下可以被使用：比如说更新进度条 92 - (void)onSocket:(AsyncSocket *)sock didReadPartialDataOfLength:(CFIndex)partialLength tag:(long)tag; 93 94 /** 95 * Called when a socket has completed writing the requested data. Not called if there is an error. 96 **/ 97 //当一个socket完全写完数据时被调用。发生错误则不调用。 98 - (void)onSocket:(AsyncSocket *)sock didWriteDataWithTag:(long)tag; 99 @end 100 101 102 @interface AsyncSocket : NSObject 103 { 104 CFSocketRef theSocket; //IPv4 accept or connect socket 105 CFSocketRef theSocket6;//Ipv6 accept or connect socket 106 CFReadStreamRef theReadStream; 107 CFWriteStreamRef theWriteStream; 108 109 CFRunLoopSourceRef theSource;//for theSocket 110 CFRunLoopSourceRef theSource6;//for theSocket6 111 CFRunLoopRef theRunLoop; 112 CFSocketContext theContext; 113 114 NSMutableArray *theReadqueue; 115 AsyncReadPacket *theCurrentRead; 116 NSTimer *theReadTimer; 117 NSMutableData *partailReadBuffer; 118 119 NSMutableArray *theWriteQueue; 120 AsyncWritePacket *theCurrentWrite; 121 NSTimer *theWriteTimer; 122 123 id theDelegate; 124 Byte theFlags; 125 126 long theUserData; 127 } 128 129 -(id)init; 130 -(id)initWithDelegate:(id)delegate; 131 -(id)initWithDelegate:(id)delegate userData:(long)userData; 132 133 -(NSString *)description;//重定义%@打印出的string 134 135 /** 136 * Use "canSafelySetDelegate" to see if there is any pending business (reads and writes) with the current delegate 137 * before changing it. It is, of course, safe to change the delegate before connecting or accepting connections. 138 **/ 139 //在改变代理之前使用canSafelySetDelegate方法来查看是否有当前代理还没做完的事情（读或者写）。 140 //在连接或接受连接之前改变代理是安全的。 141 - (id)delegate; 142 - (BOOL)canSafelySetDelegate; 143 - (void)setDelegate:(id)delegate; 144 145 /*User data can be a long,or an id or void* cast to a long. */ 146 //cast to:投射 147 -(long)userData; 148 -(void)setUserData:(long)userData; 149 150 /*Don't use these to read or write. And don't close them,either! */ 151 -(CFSocketRef)getCFSocket; 152 -(CFReadStreamRef)getCFReadStream; 153 -(CFWriteStreamRef)getCFWriteStream; 154 155 /** 156 * Once one of these methods is called, the AsyncSocket instance is locked in, and the rest can't be called without 157 * disconnecting the socket first. If the attempt times out or fails, these methods either return NO or 158 * call "onSocket:willDisconnectWithError:" and "onSockedDidDisconnect:". 159 **/ 160 // 161 - (BOOL)acceptOnPort:(UInt16)port error:(NSError **)errPtr; 162 - (BOOL)acceptOnAddress:(NSString *)hostaddr port:(UInt16)port error:(NSError **)errPtr; 163 - (BOOL)connectToHost:(NSString *)hostname onPort:(UInt16)port error:(NSError **)errPtr; 164 - (BOOL)connectToAddress:(NSData *)remoteAddr error:(NSError **)errPtr; 165 166 -(void)disconnect; 167 -(void)disconnectAfterWriting; 168 -(BOOL)isConnected; 169 -(NSString *)connectedHost; 170 -(UInt16)connectedPort; 171 -(BOOL)isIPv4; 172 -(BOOL)isIPv6; 173 174 /** 175 * The following methods won't block. To not time out, use a negative time interval. 176 * If they time out, "onSocket:disconnectWithError:" is called. The tag is for your convenience. 177 * You can use it as an array index, step number, state id, pointer, etc., just like the socket's user data. 178 **/ 179 180 //下面这些方法不会阻塞。如果想没有timeout 使用一个负数time interval 181 //如果time out时间用光了，会调用"onSocket:disconnectWithError:"方法。tag只是为了方便，就像socket中的user data一样。 182 183 /** 184 * This will read a certain number of bytes into memory, and call the delegate method when those bytes have been read. 185 * If there is an error, partially read data is lost. 186 * If the length is 0, this method does nothing and the delegate is not called. 187 **/ 188 //这个方法会从内存中读入特定数值的字节，读完之后会调用代理方法 189 //如果发生错误，被部分读入的数据会消失 190 //如果length为0，这个方法什么都不做，代理也不会被调用 191 -(void)readDataToLength:(CFIndex)length withTimeout:(NSTimeInterval)timeout tag:(long)tag; 192 193 /** 194 * This reads bytes until (and including) the passed "data" parameter, which acts as a separator. 195 * The bytes and the separator are returned by the delegate method. 196 * 197 * If you pass nil or zero-length data as the "data" parameter, 198 * the method will do nothing, and the delegate will not be called. 199 * 200 * To read a line from the socket, use the line separator (e.g. CRLF for HTTP, see below) as the "data" parameter. 201 * Note that this method is not character-set aware, so if a separator can occur naturally as part of the encoding for 202 * a character, the read will prematurely end. 203 **/ 204 205 -(void)readDataToData:(NSData *)data withTimeout:(NSTimeInterval)timeout tag:(long)tag; 206 207 /** 208 * Reads the first available bytes that become available on the socket. 209 **/ 210 211 -(void)readDataWithTimeout:(NSTimeInterval)timeout tag:(long)tag; 212 213 214 /* Writes data to the socket, and calls the delegate when finished. 215 * 216 * If you pass in nil or zero-length data, this method does nothing and the delegate will not be called. 217 **/ 218 //向调用方法的socket写入数据 219 -(void)writeData:(NSData *)data withTimeout:(NSTimeInterval)timeout tag:(long)tag; 220 221 /** 222 * Returns progress of current read or write, from 0.0 to 1.0, or NaN if no read/write (use isnan() to check). 223 * "tag", "done" and "total" will be filled in if they aren't NULL. 224 **/ 225 //返回当前读/写的进度（0.0~1.0），没有读/写时返回NaN，在tag，done，total非空时要写上 226 //typedef signed long CFIndex; 227 -(float)progressOfReadReturningTag:(long *)tag bytesDone:(CFIndex *)done total:(CFIndex *)total; 228 -(float)progressOfWriteReturningTag:(long *)tag bytesDone:(CFIndex *)done total:(CFIndex *)total; 229 230 /** 231 * In the event of an error, this method may be called during onSocket:willDisconnectWithError: to read 232 * any data that's left on the socket. 233 **/ 234 //在发生错误的时候，这个方法可能在onSocket:willDisconnectWithError:中被调用，用来读取留在socket中的数据 235 - (NSData *)unreadData; 236 237 +(NSData *)unreadData;//0x0D0A 238 +(NSData *)CRLFData;//0x0D 239 +(NSData *)LFData;//0x0A 240 +(NSData *)ZeroData;//0x00 241 @end