從前面的設置中保留字符的C代碼

Question

我已經獲得了一些在Objective-C應用程序中運行的C代碼。我從互聯網上獲取了這些代碼。

static void extract_app_name(const char *all_arguments, char **app_name) { 
    char *full_path, *app_end, *app_begin; //, *app_name_temp; 
    size_t diff; 

    if (all_arguments == NULL || app_name == NULL) { 
     return; 
    } 

    full_path = (char*)all_arguments + sizeof(int); 

    app_end = strcasestr(full_path, ".app"); 
    if (app_end == NULL) { 
     app_begin = strrchr(full_path, '/'); 
     if (app_begin != NULL) {     
      *app_name = malloc(app_begin+1); 
      *app_name = strdup(app_begin+1); 
     } else {     
      *app_name = strdup(full_path); 
     } 
    } else {    
     app_begin = app_end; 
     while (*(--app_begin) != '/') {} 
     diff = app_end - app_begin; 
     char *app_name_temp[diff]; // = malloc(diff); 
     *app_name_temp = malloc(diff); 
     *app_name = malloc(diff); 
     strncpy(*app_name_temp, app_begin+1, diff-1); 
     app_name_temp[diff]='\0'; 
     app_name = strcpy(*app_name, *app_name_temp); 
    } 
} 

此代碼的目的是從完整路徑中提取應用程序名稱。如果應用程序以.app擴展名命名，則它會從.app所產生的任何內容中提取名稱。

例如，以下內容：

extract_app_name("/Applications/Google Chrome.app/Contents/Versions/16.0.912.63/Google Chrome Helper.app/Contents/MacOS/Google Chrome Helper", &app_name); 
NSLog(@"First App is: %s", app_name); 

extract_app_name("/System/Library/Frameworks/QuickLook.framework/Resources/quicklookd.app/Contents/MacOS/quicklookd", &app_name); 
NSLog(@"Next App is: %s", app_name); 

extract_app_name("/System/Library/CoreServices/Dock.app/Contents/XPCServices/com.apple.dock.extra.xpc/Contents/MacOS/com.apple.dock.extra", &app_name); 
NSLog(@"Next App is: %s", app_name); 

extract_app_name("/Applications/Tiny", &app_name); 
NSLog(@"Next App is: %s", app_name); 

應該輸出這樣的：

First App is: Google Chrome 
Next App is: quicklookd 
Next App is: Dock 
Next app is: Tiny 

一般情況下，這是正確的。但是，如果我連續4-5次運行應用程序，我的輸出有時不會總是成功。有時第二個應該輸出quicklookd的應用程序實際上會轉儲quicklookdome（它保留了第一個應用程序名稱的一部分）。

我懷疑它與變量沒有被正確初始化，並保留內存中已有的內容。我只是不知道C足以指出它。

Answer 1

這是固定和簡化：

static void extract_app_name(const char *all_arguments, char **app_name) { 
     char *full_path, *app_end, *app_begin; //, *app_name_temp; 
     size_t diff; 

     if (all_arguments == NULL || app_name == NULL) { 
      return; 
     } 

     full_path = (char*)all_arguments + sizeof(int); 

     app_end = strcasestr(full_path, ".app"); 
     if (app_end == NULL) { 
      app_begin = strrchr(full_path, '/'); 
      if (app_begin != NULL) 
       *app_name = strdup(app_begin+1); 
      else 
       *app_name = strdup(full_path); 
     } else { 
      app_begin = app_end; 
      while (*(--app_begin) != '/') {} 
      diff = app_end - app_begin; 
      *app_name = malloc(diff);   
      strncpy(*app_name, app_begin+1, diff-1); 
     } 
    } 

請注意，您的代碼有內存泄漏。打到extract_app_name的調用者應該釋放字符串。