app: add code for macOS and Windows apps under 'app' (#12933)

* app: add code for macOS and Windows apps under 'app'

* app: add readme

* app: windows and linux only for now

* ci: fix ui CI validation

---------

Co-authored-by: jmorganca <jmorganca@gmail.com>

app/dialog/cocoa/dlg.h

@@ -0,0 +1,43 @@
+#include <objc/NSObjCRuntime.h>
+
+typedef enum {
+	MSG_YESNO,
+	MSG_ERROR,
+	MSG_INFO,
+} AlertStyle;
+
+typedef struct {
+	char* msg;
+	char* title;
+	AlertStyle style;
+} AlertDlgParams;
+
+#define LOADDLG 0
+#define SAVEDLG 1
+#define DIRDLG 2 // browse for directory
+
+typedef struct {
+	int mode; /* which dialog style to invoke (see earlier defines) */
+	char* buf; /* buffer to store selected file */
+	int nbuf; /* number of bytes allocated at buf */
+	char* title; /* title for dialog box (can be nil) */
+	void** exts; /* list of valid extensions (elements actual type is NSString*) */
+	int numext; /* number of items in exts */
+	int relaxext; /* allow other extensions? */
+	char* startDir; /* directory to start in (can be nil) */
+	char* filename; /* default filename for dialog box (can be nil) */
+	int showHidden; /* show hidden files? */
+	int allowMultiple; /* allow multiple file selection? */
+} FileDlgParams;
+
+typedef enum {
+	DLG_OK,
+	DLG_CANCEL,
+	DLG_URLFAIL,
+} DlgResult;
+
+DlgResult alertDlg(AlertDlgParams*);
+DlgResult fileDlg(FileDlgParams*);
+
+void* NSStr(void* buf, int len);
+void NSRelease(void* obj);

app/dialog/cocoa/dlg.m

@@ -0,0 +1,195 @@
+#import <Cocoa/Cocoa.h>
+#include "dlg.h"
+#include <string.h>
+#include <sys/syslimits.h>
+
+void* NSStr(void* buf, int len) {
+	return (void*)[[NSString alloc] initWithBytes:buf length:len encoding:NSUTF8StringEncoding];
+}
+
+void checkActivationPolicy() {
+	NSApplicationActivationPolicy policy = [NSApp activationPolicy];
+	// prohibited NSApp will not show the panel at all.
+	// It probably means that this is not run in a GUI app, that would set the policy on its own,
+	// but in a terminal app - setting it to accessory will allow dialogs to show
+	if (policy == NSApplicationActivationPolicyProhibited) {
+		[NSApp setActivationPolicy:NSApplicationActivationPolicyAccessory];
+	}
+}
+
+void NSRelease(void* obj) {
+	[(NSObject*)obj release];
+}
+
+@interface AlertDlg : NSObject {
+	AlertDlgParams* params;
+	DlgResult result;
+}
++ (AlertDlg*)init:(AlertDlgParams*)params;
+- (DlgResult)run;
+@end
+
+DlgResult alertDlg(AlertDlgParams* params) {
+	return [[AlertDlg init:params] run];
+}
+
+@implementation AlertDlg
++ (AlertDlg*)init:(AlertDlgParams*)params {
+	AlertDlg* d = [AlertDlg alloc];
+	d->params = params;
+	return d;
+}
+
+- (DlgResult)run {
+	if(![NSThread isMainThread]) {
+		[self performSelectorOnMainThread:@selector(run) withObject:nil waitUntilDone:YES];
+		return self->result;
+	}
+	NSAlert* alert = [[NSAlert alloc] init];
+	if(self->params->title != nil) {
+		[[alert window] setTitle:[[NSString alloc] initWithUTF8String:self->params->title]];
+	}
+	[alert setMessageText:[[NSString alloc] initWithUTF8String:self->params->msg]];
+	switch (self->params->style) {
+	case MSG_YESNO:
+		[alert addButtonWithTitle:@"Yes"];
+		[alert addButtonWithTitle:@"No"];
+		break;
+	case MSG_ERROR:
+		[alert setIcon:[NSImage imageNamed:NSImageNameCaution]];
+		[alert addButtonWithTitle:@"OK"];
+		break;
+	case MSG_INFO:
+		[alert setIcon:[NSImage imageNamed:NSImageNameInfo]];
+		[alert addButtonWithTitle:@"OK"];
+		break;
+	}
+
+	checkActivationPolicy();
+
+	self->result = [alert runModal] == NSAlertFirstButtonReturn ? DLG_OK : DLG_CANCEL;
+	return self->result;
+}
+@end
+
+@interface FileDlg : NSObject {
+	FileDlgParams* params;
+	DlgResult result;
+}
++ (FileDlg*)init:(FileDlgParams*)params;
+- (DlgResult)run;
+@end
+
+DlgResult fileDlg(FileDlgParams* params) {
+	return [[FileDlg init:params] run];
+}
+
+@implementation FileDlg
++ (FileDlg*)init:(FileDlgParams*)params {
+	FileDlg* d = [FileDlg alloc];
+	d->params = params;
+	return d;
+}
+
+- (DlgResult)run {
+	if(![NSThread isMainThread]) {
+		[self performSelectorOnMainThread:@selector(run) withObject:nil waitUntilDone:YES];
+	} else if(self->params->mode == SAVEDLG) {
+		self->result = [self save];
+	} else {
+		self->result = [self load];
+	}
+	return self->result;
+}
+
+- (NSInteger)runPanel:(NSSavePanel*)panel {
+	[panel setFloatingPanel:YES];
+	[panel setShowsHiddenFiles:self->params->showHidden ? YES : NO];
+	[panel setCanCreateDirectories:YES];
+	if(self->params->title != nil) {
+		[panel setTitle:[[NSString alloc] initWithUTF8String:self->params->title]];
+	}
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wdeprecated-declarations"
+	if(self->params->numext > 0) {
+		[panel setAllowedFileTypes:[NSArray arrayWithObjects:(NSString**)self->params->exts count:self->params->numext]];
+	}
+#pragma clang diagnostic pop
+	if(self->params->relaxext) {
+		[panel setAllowsOtherFileTypes:YES];
+	}
+	if(self->params->startDir) {
+		[panel setDirectoryURL:[NSURL URLWithString:[[NSString alloc] initWithUTF8String:self->params->startDir]]];
+	}
+	if(self->params->filename != nil) {
+		[panel setNameFieldStringValue:[[NSString alloc] initWithUTF8String:self->params->filename]];
+	}
+
+	checkActivationPolicy();
+
+	return [panel runModal];
+}
+
+- (DlgResult)save {
+	NSSavePanel* panel = [NSSavePanel savePanel];
+	if(![self runPanel:panel]) {
+		return DLG_CANCEL;
+	} else if(![[panel URL] getFileSystemRepresentation:self->params->buf maxLength:self->params->nbuf]) {
+		return DLG_URLFAIL;
+	}
+	return DLG_OK;
+}
+
+- (DlgResult)load {
+	NSOpenPanel* panel = [NSOpenPanel openPanel];
+	if(self->params->mode == DIRDLG) {
+		[panel setCanChooseDirectories:YES];
+		[panel setCanChooseFiles:NO];
+	}
+	
+	if(self->params->allowMultiple) {
+		[panel setAllowsMultipleSelection:YES];
+	}
+	
+	if(![self runPanel:panel]) {
+		return DLG_CANCEL;
+	}
+	
+	NSArray* urls = [panel URLs];
+	if(self->params->allowMultiple && [urls count] >= 1) {
+		// For multiple files, we need to return all paths separated by null bytes
+		char* bufPtr = self->params->buf;
+		int remainingBuf = self->params->nbuf;
+		
+  // Calculate total required buffer size first
+  int totalSize = 0;
+  for(NSURL* url in urls) {
+      char tempBuf[PATH_MAX];
+      if(![url getFileSystemRepresentation:tempBuf maxLength:PATH_MAX]) {
+          return DLG_URLFAIL;
+      }
+      totalSize += strlen(tempBuf) + 1; // +1 for null terminator
+  }
+  totalSize += 1; // Final null terminator
+
+  if(totalSize > self->params->nbuf) {
+      // Not enough buffer space
+      return DLG_URLFAIL;
+  }
+
+  // Now actually copy the paths (we know we have space)
+  bufPtr = self->params->buf;
+  for(NSURL* url in urls) {
+      char tempBuf[PATH_MAX];
+      [url getFileSystemRepresentation:tempBuf maxLength:PATH_MAX];
+      int pathLen = strlen(tempBuf);
+      strcpy(bufPtr, tempBuf);
+      bufPtr += pathLen + 1;
+  }
+  *bufPtr = '\0'; // Final null terminator
+	}
+	
+	return DLG_OK;
+}
+
+@end

app/dialog/cocoa/dlg_darwin.go

@@ -0,0 +1,183 @@
+package cocoa
+
+// #cgo darwin LDFLAGS: -framework Cocoa
+// #include <stdlib.h>
+// #include <sys/syslimits.h>
+// #include "dlg.h"
+import "C"
+
+import (
+	"bytes"
+	"errors"
+	"unsafe"
+)
+
+type AlertParams struct {
+	p C.AlertDlgParams
+}
+
+func mkAlertParams(msg, title string, style C.AlertStyle) *AlertParams {
+	a := AlertParams{C.AlertDlgParams{msg: C.CString(msg), style: style}}
+	if title != "" {
+		a.p.title = C.CString(title)
+	}
+	return &a
+}
+
+func (a *AlertParams) run() C.DlgResult {
+	return C.alertDlg(&a.p)
+}
+
+func (a *AlertParams) free() {
+	C.free(unsafe.Pointer(a.p.msg))
+	if a.p.title != nil {
+		C.free(unsafe.Pointer(a.p.title))
+	}
+}
+
+func nsStr(s string) unsafe.Pointer {
+	return C.NSStr(unsafe.Pointer(&[]byte(s)[0]), C.int(len(s)))
+}
+
+func YesNoDlg(msg, title string) bool {
+	a := mkAlertParams(msg, title, C.MSG_YESNO)
+	defer a.free()
+	return a.run() == C.DLG_OK
+}
+
+func InfoDlg(msg, title string) {
+	a := mkAlertParams(msg, title, C.MSG_INFO)
+	defer a.free()
+	a.run()
+}
+
+func ErrorDlg(msg, title string) {
+	a := mkAlertParams(msg, title, C.MSG_ERROR)
+	defer a.free()
+	a.run()
+}
+
+const (
+	BUFSIZE             = C.PATH_MAX
+	MULTI_FILE_BUF_SIZE = 32768
+)
+
+// MultiFileDlg opens a file dialog that allows multiple file selection
+func MultiFileDlg(title string, exts []string, relaxExt bool, startDir string, showHidden bool) ([]string, error) {
+	return fileDlgWithOptions(C.LOADDLG, title, exts, relaxExt, startDir, "", showHidden, true)
+}
+
+// FileDlg opens a file dialog for single file selection (kept for compatibility)
+func FileDlg(save bool, title string, exts []string, relaxExt bool, startDir string, filename string, showHidden bool) (string, error) {
+	mode := C.LOADDLG
+	if save {
+		mode = C.SAVEDLG
+	}
+	files, err := fileDlgWithOptions(mode, title, exts, relaxExt, startDir, filename, showHidden, false)
+	if err != nil {
+		return "", err
+	}
+	if len(files) == 0 {
+		return "", nil
+	}
+	return files[0], nil
+}
+
+func DirDlg(title string, startDir string, showHidden bool) (string, error) {
+	files, err := fileDlgWithOptions(C.DIRDLG, title, nil, false, startDir, "", showHidden, false)
+	if err != nil {
+		return "", err
+	}
+	if len(files) == 0 {
+		return "", nil
+	}
+	return files[0], nil
+}
+
+// fileDlgWithOptions is the unified file dialog function that handles both single and multiple selection
+func fileDlgWithOptions(mode int, title string, exts []string, relaxExt bool, startDir, filename string, showHidden, allowMultiple bool) ([]string, error) {
+	// Use larger buffer for multiple files, smaller for single
+	bufSize := BUFSIZE
+	if allowMultiple {
+		bufSize = MULTI_FILE_BUF_SIZE
+	}
+
+	p := C.FileDlgParams{
+		mode: C.int(mode),
+		nbuf: C.int(bufSize),
+	}
+
+	if allowMultiple {
+		p.allowMultiple = C.int(1) // Enable multiple selection //nolint:structcheck
+	}
+	if showHidden {
+		p.showHidden = 1
+	}
+
+	p.buf = (*C.char)(C.malloc(C.size_t(bufSize)))
+	defer C.free(unsafe.Pointer(p.buf))
+	buf := (*(*[MULTI_FILE_BUF_SIZE]byte)(unsafe.Pointer(p.buf)))[:bufSize]
+
+	if title != "" {
+		p.title = C.CString(title)
+		defer C.free(unsafe.Pointer(p.title))
+	}
+	if startDir != "" {
+		p.startDir = C.CString(startDir)
+		defer C.free(unsafe.Pointer(p.startDir))
+	}
+	if filename != "" {
+		p.filename = C.CString(filename)
+		defer C.free(unsafe.Pointer(p.filename))
+	}
+
+	if len(exts) > 0 {
+		if len(exts) > 999 {
+			panic("more than 999 extensions not supported")
+		}
+		ptrSize := int(unsafe.Sizeof(&title))
+		p.exts = (*unsafe.Pointer)(C.malloc(C.size_t(ptrSize * len(exts))))
+		defer C.free(unsafe.Pointer(p.exts))
+		cext := (*(*[999]unsafe.Pointer)(unsafe.Pointer(p.exts)))[:]
+		for i, ext := range exts {
+			cext[i] = nsStr(ext)
+			defer C.NSRelease(cext[i])
+		}
+		p.numext = C.int(len(exts))
+		if relaxExt {
+			p.relaxext = 1
+		}
+	}
+
+	// Execute dialog and parse results
+	switch C.fileDlg(&p) {
+	case C.DLG_OK:
+		if allowMultiple {
+			// Parse multiple null-terminated strings from buffer
+			var files []string
+			start := 0
+			for i := range len(buf) - 1 {
+				if buf[i] == 0 {
+					if i > start {
+						files = append(files, string(buf[start:i]))
+					}
+					start = i + 1
+					// Check for double null (end of list)
+					if i+1 < len(buf) && buf[i+1] == 0 {
+						break
+					}
+				}
+			}
+			return files, nil
+		} else {
+			// Single file - return as array for consistency
+			filename := string(buf[:bytes.Index(buf, []byte{0})])
+			return []string{filename}, nil
+		}
+	case C.DLG_CANCEL:
+		return nil, nil
+	case C.DLG_URLFAIL:
+		return nil, errors.New("failed to get file-system representation for selected URL")
+	}
+	panic("unhandled case")
+}