The getTitle(int i) function retrieves the title of a window with the specified layer index i by searching through an array of window dictionaries and constructing a string with the window's layer index and owner name.

The getTitle(int i) function searches for a window with a matching layer index i in an array of window dictionaries.
If found, it constructs a string with the window's layer index and owner name, and returns a duplicate of this string as a C-style string.

Run example

npm run import -- "lookup window by"

lookup window by

__attribute__((visibility("default")))
const char* getTitle(int i) {
    if (windows == NULL) {
        count = enumWindows();
    }

    NSDictionary* targetWindow = nil;
    for (NSDictionary* window in windows) {
        NSNumber* windowLayer = (NSNumber*)[window objectForKey:(__bridge NSString*)kCGWindowLayer];
        if (windowLayer && [windowLayer intValue] == i) { // Compare with the provided index
            targetWindow = window;
            break;
        }
    }

    if (!targetWindow) {
        return NULL;
    }

    NSString* windowName = (NSString*)[targetWindow objectForKey:(__bridge NSString*)kCGWindowOwnerName];
    NSNumber* windowLayer = (NSNumber*)[targetWindow objectForKey:(__bridge NSString*)kCGWindowLayer];
    NSString* res = [NSString stringWithFormat:@"%@: %s", windowLayer, [windowName UTF8String]];
    
    return strdup([res UTF8String]); // Use strdup to return a persistent C-string
}

/**
 * Returns the title of the window with the specified layer number.
 *
 * @param layer The layer number of the window to retrieve the title for.
 * @return A string containing the window title, or NULL if no window with the specified layer number is found.
 */
__attribute__((visibility("default")))
const char* getTitle(int layer) {
    static NSArray* windows = nil;
    
    // Enumerate windows once and store the result in a static array to avoid redundant enumeration
    if (windows == nil) {
        windows = enumWindows();
    }

    // Use KVO to iterate over the array for better performance
    NSDictionary* targetWindow = [windows firstObjectWithKeysPassingTest:^BOOL(id obj, NSDictionary* key) {
        NSNumber* windowLayer = key;
        return [windowLayer intValue] == layer;
    }];

    if (!targetWindow) {
        // Return NULL if no window with the specified layer number is found
        return NULL;
    }

    // Use string properties for better readability and thread-safety
    NSString* title = targetWindow[kCGWindowOwnerName];
    NSNumber* windowLayer = targetWindow[kCGWindowLayer];
    NSString* result = [NSString stringWithFormat:@"%@: %d", title, [windowLayer intValue]];
    
    // Use a more modern and safer way to create a C-string
    return [result UTF8String];
}

Code Breakdown

Code Attributes

• __attribute__((visibility("default"))): This attribute specifies the visibility of the function in the compiled binary. In this case, it is set to "default", which means the function will be visible to other objects outside the current unit.

Function getTitle(int i)

• Purpose: Retrieves the title of a window with the specified layer index.
• Parameters:
  • i: The layer index of the target window.
• Variables:
  • windows: An array of dictionaries containing window information. It is assumed to be initialized elsewhere.
  • targetWindow: A temporary dictionary variable to store the target window.
  • count: A variable used to store the number of windows, initialized in the enumWindows() function.
• Flow:
  1. If the windows array is empty, it is populated by calling the enumWindows() function.
  2. Iterate through the windows array and check if the current window's layer index matches the provided i. If a match is found, store the window in targetWindow and break the loop.
  3. If no matching window is found, return NULL.
  4. Extract the window's owner name and layer index from the targetWindow dictionary.
  5. Construct a string with the window's layer index and owner name.
  6. Return a duplicate of the constructed string using strdup.

Function Return Value

• The function returns a C-style string (a pointer to a character array) using strdup. This ensures the returned string is persistent and can be stored or used by other functions.