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Xcode 代码注释自动缩进插件:开发教程及源码

Xcode 代码注释自动缩进插件:开发教程及源码

自从公司启用代码review以来,每个开发者的代码风格渐渐保持一致了,看到规范统一的代码就是觉得比较舒服。

不过Xcode的代码注释功能一直用着很别扭,比如下面的例子:

//注释前: - (void)viewDidLoad {     [super viewDidLoad];     self.view.backgroundColor = [UIColor whiteColor]; } //注释后: - (void)viewDidLoad {     [super viewDidLoad]; //    self.view.backgroundColor = [UIColor whiteColor]; } //注释前: - (void)viewDidLoad {     [super viewDidLoad];       self.view.backgroundColor = [UIColor whiteColor]; }   //注释后: - (void)viewDidLoad {     [super viewDidLoad];   //    self.view.backgroundColor = [UIColor whiteColor]; }

可以看到,Xcode只是在行开头加上注释符,注释后的代码缩进对不齐,很难看。这对患有神经感官歇斯底里毛细血管穿梭图鲁西斯症候群(简称强迫症)的人来说,是一件非常痛苦的事情。

在stackoverflow搜了一下,发现有人也提了这个问题,然后有个人回答说:

  1. 你先按command + [把代码往左缩进到最前面

  2. 再按command + /注释代码

  3. 最后按command + ]把代码往右缩进

结果这条回答被采纳为最差答案。

所以我只能自己写个插件来让注释自动缩进了,首先新建一个Xcode插件工程,比较详细的创建过程可以见《 Xcode插件AllTargets开发教程 》。

一开始要先整理一下写插件的思路,我们使用快捷键command + /的时候,Xcode肯定会调用一个方法来注释代码,这个方法实现的功能应该是在代码行最前面加上//注释符。

而当我们写的代码有缩进的话,缩进的地方都是空格,所以我们可以hook注释的方法,把注释符改为插入到第一个非空格字符前就行了。

接下来就开始查找代码注释的方法了,首先在Xcode的私有类头文件里搜索comment,可以发现一个比较可疑的方法:- (void)commentAndUncommentCurrentLines:(id)arg1;,hook这个方法,把参数arg1打印出来,参考代码如下:

#import "DVTSourceTextView+Hook.h" @implementation DVTSourceTextView (Hook) + (void)hook {     [self jr_swizzleMethod:@selector(commentAndUncommentCurrentLines:)                 withMethod:@selector(hook_commentAndUncommentCurrentLines:)                      error:nil]; } - (void)hook_commentAndUncommentCurrentLines:(id)arg1 {     NSLog(@"%@", arg1);     [self hook_commentAndUncommentCurrentLines:arg1]; } @end #import "DVTSourceTextView+Hook.h"   @implementation DVTSourceTextView (Hook)   + (void)hook {     [self jr_swizzleMethod:@selector(commentAndUncommentCurrentLines:)                 withMethod:@selector(hook_commentAndUncommentCurrentLines:)                      error:nil]; }   - (void)hook_commentAndUncommentCurrentLines:(id)arg1 {     NSLog(@"%@", arg1);     [self hook_commentAndUncommentCurrentLines:arg1]; }   @end

使用command + /对代码进行注释和反注释,输出结果为:

由此可知,使用快捷键注释,实际上是调用了Xcode菜单栏点击的方法。而当我们注释代码时,会有log打印,也说明找对了方法。

commentAndUncommentCurrentLines:这个方法位于DVTSourceTextView类中,而这个类位于DVTKit.framework里,接下来打开反汇编软件Hopper Disassembler,把DVTKit.framework拖进去进行反汇编。

搜索并选中commentAndUncommentCurrentLines:方法,按alt + enter生成伪代码,由于代码太长所以只贴出关键代码:

void -[DVTSourceTextView commentAndUncommentCurrentLines:](void * self, void * _cmd, void * arg2) {     //......     rax = (r12)(r15, @selector(stringByTogglingCommentsInLineRange:), rdx, r13);     //...... } void -[DVTSourceTextView commentAndUncommentCurrentLines:](void * self, void * _cmd, void * arg2) {     //......       rax = (r12)(r15, @selector(stringByTogglingCommentsInLineRange:), rdx, r13);       //...... }

由上面的代码可知,stringByTogglingCommentsInLineRange:方法返回了注释或反注释后的字符串,接着再搜索并查看该方法的伪代码:

void * -[DVTSourceLanguageService stringByTogglingCommentsInLineRange:](void * self, void * _cmd, struct _NSRange arg2)  {     //......     if (var_70 == 0x2) {         rbx = [[rdi stringByUncommentingString:r15] retain];     } else {         rbx = [[rdi stringByCommentingString:r15] retain];     }     //...... } void * -[DVTSourceLanguageService stringByTogglingCommentsInLineRange:](void * self, void * _cmd, struct _NSRange arg2)  {     //......       if (var_70 == 0x2) {         rbx = [[rdi stringByUncommentingString:r15] retain];     } else {         rbx = [[rdi stringByCommentingString:r15] retain];     }       //...... }

同理,继续查看stringByCommentingString:方法的伪代码:

void * -[DVTSourceLanguageService stringByCommentingString:](void * self, void * _cmd, void * arg2) {     rdx = arg2;     r15 = self;     r12 = [rdx retain];     r14 = *objc_msgSend;     rbx = [[r15 lineCommentPrefixes] retain];     r13 = [[rbx firstObject] retain];     [rbx release];     if ([r13 length] != 0x0) {             r15 = r13;     }     else {             r14 = *objc_msgSend;             var_30 = r12;             rbx = [[r15 blockCommentCircumfixes] retain];             r12 = [[rbx firstObject] retain];             r15 = *objc_release;             [rbx release];             rbx = r15;             r15 = [[r12 firstObject] retain];             [r13 release];             r13 = [[r12 lastObject] retain];             [r12 release];             if (r13 != 0x0) {                     r12 = [[var_30 stringByAppendingString:r13] retain];                     (rbx)(var_30, @selector(stringByAppendingString:));                     (rbx)(r13, @selector(stringByAppendingString:));             }             else {                     r12 = var_30;             }     }     rbx = [[r15 stringByAppendingString:r12] retain];     r14 = *objc_release;     [r12 release];     [r15 release];     rdi = rbx;     rax = [rdi autorelease];     return rax; } void * -[DVTSourceLanguageService stringByCommentingString:](void * self, void * _cmd, void * arg2) {     rdx = arg2;     r15 = self;     r12 = [rdx retain];     r14 = *objc_msgSend;     rbx = [[r15 lineCommentPrefixes] retain];     r13 = [[rbx firstObject] retain];     [rbx release];     if ([r13 length] != 0x0) {             r15 = r13;     }     else {             r14 = *objc_msgSend;             var_30 = r12;             rbx = [[r15 blockCommentCircumfixes] retain];             r12 = [[rbx firstObject] retain];             r15 = *objc_release;             [rbx release];             rbx = r15;             r15 = [[r12 firstObject] retain];             [r13 release];             r13 = [[r12 lastObject] retain];             [r12 release];             if (r13 != 0x0) {                     r12 = [[var_30 stringByAppendingString:r13] retain];                     (rbx)(var_30, @selector(stringByAppendingString:));                     (rbx)(r13, @selector(stringByAppendingString:));             }             else {                     r12 = var_30;             }     }     rbx = [[r15 stringByAppendingString:r12] retain];     r14 = *objc_release;     [r12 release];     [r15 release];     rdi = rbx;     rax = [rdi autorelease];     return rax; }

这个方法的作用是把待注释的代码加上注释符进行注释,这也是Xcode注释代码的具体实现方法,将伪代码翻译成OC代码为:

- (NSString *)stringByCommentingString:(NSString *)commentingString {     NSString *lineCommentPrefix = [self.lineCommentPrefixes firstObject];     if (lineCommentPrefix.length == 0) {         // 使用 `/* */` 注释块         NSArray *blockCommentCircumfix = [self.blockCommentCircumfixes firstObject];         lineCommentPrefix = [blockCommentCircumfix firstObject];         NSString *lineCommentSuffix = [blockCommentCircumfix lastObject];         if (lineCommentSuffix) {             commentingString = [commentingString stringByAppendingString:lineCommentSuffix];         }     }     //在待注释的代码最前面加上注释符     return [lineCommentPrefix stringByAppendingString:commentingString]; } - (NSString *)stringByCommentingString:(NSString *)commentingString {     NSString *lineCommentPrefix = [self.lineCommentPrefixes firstObject];       if (lineCommentPrefix.length == 0) {           // 使用 `/* */` 注释块         NSArray *blockCommentCircumfix = [self.blockCommentCircumfixes firstObject];         lineCommentPrefix = [blockCommentCircumfix firstObject];           NSString *lineCommentSuffix = [blockCommentCircumfix lastObject];         if (lineCommentSuffix) {             commentingString = [commentingString stringByAppendingString:lineCommentSuffix];         }     }       //在待注释的代码最前面加上注释符     return [lineCommentPrefix stringByAppendingString:commentingString]; }

因此我们可以hook这个方法,在第一个非空格字符的位置插入注释符。

如果某一行代码是空行的话,就不需要注释了,我看了大部分的编辑器都是这么处理的。

参考代码如下:

- (NSString *)hook_stringByCommentingString:(NSString *)commentingString {     NSString *lineCommentPrefix = [self.lineCommentPrefixes firstObject];     if (lineCommentPrefix.length == 0) {         // 使用 `/* */` 注释块         NSArray *blockCommentCircumfix = [self.blockCommentCircumfixes firstObject];         lineCommentPrefix = [blockCommentCircumfix firstObject];         NSString *lineCommentSuffix = [blockCommentCircumfix lastObject];         if (lineCommentSuffix) {             commentingString = [commentingString stringByAppendingString:lineCommentSuffix];         }     }     // 判断代码是否含有非空格字符     NSRange range = [commentingString rangeOfString:@"[^//s]" options:NSRegularExpressionSearch];     if (range.location == NSNotFound) {         // 如果没有非空格字符,就不注释         return commentingString;     }     // 在第一个非空格字符的位置插入注释符     NSMutableString *mutableString = [commentingString mutableCopy];     [mutableString insertString:lineCommentPrefix atIndex:range.location];     return [mutableString copy]; } - (NSString *)hook_stringByCommentingString:(NSString *)commentingString {     NSString *lineCommentPrefix = [self.lineCommentPrefixes firstObject];       if (lineCommentPrefix.length == 0) {           // 使用 `/* */` 注释块         NSArray *blockCommentCircumfix = [self.blockCommentCircumfixes firstObject];         lineCommentPrefix = [blockCommentCircumfix firstObject];           NSString *lineCommentSuffix = [blockCommentCircumfix lastObject];         if (lineCommentSuffix) {             commentingString = [commentingString stringByAppendingString:lineCommentSuffix];         }     }       // 判断代码是否含有非空格字符     NSRange range = [commentingString rangeOfString:@"[^//s]" options:NSRegularExpressionSearch];     if (range.location == NSNotFound) {         // 如果没有非空格字符,就不注释         return commentingString;     }       // 在第一个非空格字符的位置插入注释符     NSMutableString *mutableString = [commentingString mutableCopy];     [mutableString insertString:lineCommentPrefix atIndex:range.location];     return [mutableString copy]; }

插件下载地址为: https://github.com/poboke/IndentComments

安装插件后,使用效果如下所示:

Xcode 代码注释自动缩进插件:开发教程及源码

原文  http://www.cocoachina.com/ios/20151229/14806.html

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