vlib: add a clipboard module (Windows, macOS, X)

vlib/clipboard/clipboard_darwin.v

@@ -0,0 +1,66 @@
+module clipboard
+
+#include <libkern/OSAtomic.h>
+#include <Cocoa/Cocoa.h>
+
+#flag -framework Cocoa
+
+struct Clipboard {
+    pb voidptr
+    last_cb_serial i64
+}
+
+fn new_clipboard() &Clipboard{
+	mut pb := voidptr(0)
+	#pb = [NSPasteboard generalPasteboard];
+	cb := &Clipboard{
+		pb: pb
+	}
+	return cb
+}
+
+fn (cb &Clipboard) check_availability() bool {
+	return cb.pb != C.NULL
+}
+
+fn (cb &Clipboard) clear(){
+	#[cb->pb clearContents];
+}
+
+fn (cb &Clipboard) free(){
+	//nothing to free
+}
+
+fn (cb &Clipboard) has_ownership() bool {
+	if cb.last_cb_serial == 0 {return false}
+	#return [cb->pb changeCount] == cb->last_cb_serial;
+	return false
+}
+
+fn (cb &Clipboard) set_text(text string) bool {
+	#NSString *ns_clip;
+	mut ret := false
+
+	#ns_clip = [[ NSString alloc ] initWithBytesNoCopy:text.str length:text.len encoding:NSUTF8StringEncoding freeWhenDone: false];
+	#[cb->pb declareTypes:[NSArray arrayWithObject:NSStringPboardType] owner:nil];
+	#ret = [cb->pb setString:ns_clip forType:NSStringPboardType];
+	#[ns_clip release];
+
+	mut serial := 0
+	#serial = [cb->pb changeCount];
+	C.OSAtomicCompareAndSwapLong(cb.last_cb_serial, serial, &cb.last_cb_serial)
+	return ret
+}
+
+fn (cb &Clipboard) get_text() string {
+	#NSString *ns_clip;
+	mut utf8_clip := byteptr(0)
+
+	#ns_clip = [cb->pb stringForType:NSStringPboardType]; //NSPasteboardTypeString
+	#if (ns_clip == nil) {
+	#	return tos3(""); //in case clipboard is empty
+	#}
+
+	#utf8_clip = [ns_clip UTF8String];
+	return string(utf8_clip)
+}