This macOS code retrieves a list of open windows and their titles, storing them in global variables and using two functions: enumWindows to get the list of windows and getTitle to retrieve the title of each window. The main function iterates over the list of windows, calling getTitle to print each title to the console.

Run example

npm run import -- "enum windows with cocoa"

enum windows with cocoa

@import Cocoa;

static NSArray* windows;
static NSUInteger count;

#if __cplusplus
extern "C" {
#endif

__attribute__((visibility("default")))
int enumWindows()
{
	CGWindowListOption listOptions = kCGWindowListOptionAll;
	listOptions |= kCGWindowListOptionOnScreenOnly;
	listOptions |= kCGWindowListExcludeDesktopElements;

	// Ask the window server for the list of windows.
	windows = (NSArray*)CGWindowListCopyWindowInfo(listOptions, kCGNullWindowID);
	count = [windows count];

	return count;
}

__attribute__((visibility("default")))
const char* getTitle(int i) {
	if(windows == NULL) {
		count	= enumWindows();
	}
	//for (NSUInteger i = 0; i < count; i++) {
	//}
	NSDictionary*   nswindowsdescription = [windows objectAtIndex:i];
	//NSNumber* windowid = (NSNumber*)[nswindowsdescription objectForKey:@"kCGWindowNumber"];
	NSString* windowName = (NSString*)[nswindowsdescription objectForKey:@"kCGWindowOwnerName"];
	NSNumber* windowLayer = (NSNumber*)[nswindowsdescription objectForKey:@"kCGWindowLayer"];
	NSString* res = [NSString stringWithFormat:@"%@: %s", windowLayer, [windowName UTF8String]];
	return (char *)[res UTF8String];
}


int main(int argc, char *argv[])
{
    int count = enumWindows();
		for(int i = 0; i < count; i++) {
			printf("%s\n", getTitle(i));
		}
}

#if __cplusplus
}
#endif

#import 

// Global variables to store the list of windows and its count
static NSArray* windows;
static NSUInteger count;

// Function to enumerate all windows
__attribute__((visibility("default")))
NSUInteger enumerateWindows(CGWindowListOption listOptions) {
    // Ask the window server for the list of windows.
    windows = (NSArray*)CGWindowListCopyWindowInfo(listOptions, kCGNullWindowID);
    count = [windows count];
    return count;
}

// Function to get the title of a window
__attribute__((visibility("default")))
const char* getWindowTitle(NSString* windowName) {
    // Create a string with the window title
    NSString* windowTitle = [NSString stringWithFormat:@"%@: %s", [windows objectAtIndex:0][@"kCGWindowLayer"], [windowName UTF8String]];
    return (const char*)[windowTitle UTF8String];
}

// Function to get the title of a window at a given index
__attribute__((visibility("default")))
const char* getWindowTitleAtIndex(NSUInteger index) {
    if (windows == nil) {
        enumerateWindows(kCGWindowListOptionAll);
    }
    // Check if the index is within bounds
    if (index < [windows count]) {
        NSDictionary* windowInfo = [windows objectAtIndex:index];
        NSString* windowName = windowInfo[@"kCGWindowOwnerName"];
        return (const char*)[getWindowTitle(windowName) UTF8String];
    } else {
        return NULL;
    }
}

int main(int argc, char *argv[]) {
    // Get the number of windows
    NSUInteger windowCount = enumerateWindows(kCGWindowListOptionAll);
    
    // Print the title of each window
    for (NSUInteger i = 0; i < windowCount; i++) {
        printf("%s\n", getWindowTitleAtIndex(i));
    }
    
    return 0;
}

Code Breakdown

Import and Global Variables

• The code starts by importing the Cocoa framework using @import Cocoa;.
• Two global variables are declared: windows as an NSArray* and count as an NSUInteger.

enumWindows Function

• The enumWindows function is declared with the __attribute__((visibility("default"))) attribute, making it visible to other processes.
• The function takes no arguments and returns an integer.
• It uses the CGWindowListCopyWindowInfo function to retrieve a list of windows from the window server.
• The listOptions variable is set to retrieve all windows, excluding desktop elements.
• The retrieved list of windows is stored in the global windows variable.
• The count of windows is stored in the global count variable.
• The function returns the count of windows.

getTitle Function

• The getTitle function is declared with the __attribute__((visibility("default"))) attribute, making it visible to other processes.
• The function takes an integer i as an argument and returns a const char*.
• If the global windows variable is null, the enumWindows function is called to retrieve the list of windows.
• The function retrieves a dictionary representing a window from the global windows array using the objectAtIndex:i method.
• The dictionary is then used to retrieve the window's owner name and layer.
• The retrieved information is formatted into a string and returned as a const char*.

main Function

• The main function is the entry point of the program.
• It calls the enumWindows function to retrieve the count of windows.
• It then iterates over the list of windows using a for loop.
• For each window, the getTitle function is called to retrieve the window's title.
• The title is then printed to the console using printf.

C++ Compatibility

• The code uses extern "C" to ensure compatibility with C++ code.
• The #if __cplusplus and #endif directives are used to conditionally include C++-specific code.