hyperlinks: add support for optional id parameter

OSC8 escape sequences allow for marking up hyperlinks in the terminal.
An optional `id` parameter is defined to allow applications to signal to
the terminal that (potentially) broken character sequences belong to the
same URL and should be treated as if they were connected.

Add support for optional id parameters, set by the application. Update
test case for ti.EnterUrl.

Fixes: gdamore#568
Reference: https://gist.github.com/egmontkob/eb114294efbcd5adb1944c9f3cb5feda#hover-underlining-and-the-id-parameter

style.go

@@ -27,6 +27,7 @@ type Style struct {
 	bg    Color
 	attrs AttrMask
 	url   string
+	urlId string
 }
 
 // StyleDefault represents a default style, based upon the context.
@@ -44,6 +45,7 @@ func (s Style) Foreground(c Color) Style {
 		bg:    s.bg,
 		attrs: s.attrs,
 		url:   s.url,
+		urlId: s.urlId,
 	}
 }
 
@@ -55,6 +57,7 @@ func (s Style) Background(c Color) Style {
 		bg:    c,
 		attrs: s.attrs,
 		url:   s.url,
+		urlId: s.urlId,
 	}
 }
 
@@ -71,13 +74,15 @@ func (s Style) setAttrs(attrs AttrMask, on bool) Style {
 			bg:    s.bg,
 			attrs: s.attrs | attrs,
 			url:   s.url,
+			urlId: s.urlId,
 		}
 	}
 	return Style{
 		fg:    s.fg,
 		bg:    s.bg,
 		attrs: s.attrs &^ attrs,
 		url:   s.url,
+		urlId: s.urlId,
 	}
 }
 
@@ -139,6 +144,7 @@ func (s Style) Attributes(attrs AttrMask) Style {
 		bg:    s.bg,
 		attrs: attrs,
 		url:   s.url,
+		urlId: s.urlId,
 	}
 }
 
@@ -151,5 +157,20 @@ func (s Style) Url(url string) Style {
 		bg:    s.bg,
 		attrs: s.attrs,
 		url:   url,
+		urlId: s.urlId,
+	}
+}
+
+// UrlId returns a style with the UrlId set. If the provided UrlId is not empty,
+// any marked up Url with this style will be given the UrlId also. If the
+// terminal supports it, any tex with the same UrlId will be grouped as if it
+// were one Url, even if it spans multiple lines.
+func (s Style) UrlId(id string) Style {
+	return Style{
+		fg:    s.fg,
+		bg:    s.bg,
+		attrs: s.attrs,
+		url:   s.url,
+		urlId: "id:" + id,
 	}
 }

terminfo/terminfo_test.go

@@ -36,11 +36,10 @@ var testTerminfo = &Terminfo{
 	Mouse:     "\x1b[M",
 	SetCursor: "\x1b[%i%p1%d;%p2%dH",
 	PadChar:   "\x00",
-	EnterUrl:  "\x1b]8;;%p1%s\x1b\\",
+	EnterUrl:  "\x1b]8;%p2%s;%p1%s\x1b\\",
 }
 
 func TestTerminfoExpansion(t *testing.T) {
-
 	ti := testTerminfo
 
 	// Tests %i and basic parameter strings too
@@ -140,6 +139,10 @@ func TestStringParameter(t *testing.T) {
 	if s != "\x1b]8;;https://example.org/test\x1b\\" {
 		t.Errorf("Result string failed: %s", s)
 	}
+	s = ti.TParm(ti.EnterUrl, "https://example.org/test", "id:1234")
+	if s != "\x1b]8;id:1234;https://example.org/test\x1b\\" {
+		t.Errorf("Result string failed: %s", s)
+	}
 }
 
 func BenchmarkSetFgBg(b *testing.B) {

tscreen.go

@@ -346,7 +346,7 @@ func (t *tScreen) prepareExtendedOSC() {
 		t.enterUrl = t.ti.EnterUrl
 		t.exitUrl = t.ti.ExitUrl
 	} else if t.ti.Mouse != "" {
-		t.enterUrl = "\x1b]8;;%p1%s\x1b\\"
+		t.enterUrl = "\x1b]8;%p2%s;%p1%s\x1b\\"
 		t.exitUrl = "\x1b]8;;\x1b\\"
 	}
 
@@ -794,7 +794,7 @@ func (t *tScreen) drawCell(x, y int) int {
 		// URL string can be long, so don't send it unless we really need to
 		if t.enterUrl != "" && t.curstyle != style {
 			if style.url != "" {
-				t.TPuts(ti.TParm(t.enterUrl, style.url))
+				t.TPuts(ti.TParm(t.enterUrl, style.url, style.urlId))
 			} else {
 				t.TPuts(t.exitUrl)
 			}