hyperlinks: better parsing of emails without mailto prefixes

Add some new tests from the emails I have and make them work by
adjusting the code that looks for hyperlinks.

The idea is to treat "inline" emails (those without mailto:) a little
bit different and stop a little earlier while looking for their ends.

Signed-off-by: Vitaly Ovchinnikov <v@postbox.nz>
Acked-by: Robin Jarry <robin@jarry.cc>

2 files changed, 36 insertions, 1 deletions

diff --git a/lib/parse/hyperlinks.go b/lib/parse/hyperlinks.go
index dd334dd4..1200f936 100644
--- a/lib/parse/hyperlinks.go
+++ b/lib/parse/hyperlinks.go
@@ -37,6 +37,9 @@ func HttpLinks(r io.Reader) (io.Reader, []string) {
 		scheme = j - i
 		j = scheme
 
+		// "inline" email without a mailto: prefix - add some extra checks for those
+		inlineEmail := len(match) > 4 && match[2] == -1 && match[4] == -1
+
 		for !emitUrl && j < len(b) && bytes.IndexByte(urichars, b[j]) != -1 {
 			switch b[j] {
 			case '[':
@@ -69,9 +72,21 @@ func HttpLinks(r io.Reader) (io.Reader, []string) {
 				} else {
 					j++
 				}
+			case '&':
+				if inlineEmail {
+					emitUrl = true
+				} else {
+					j++
+				}
 			default:
 				j++
 			}
+
+			// we don't want those in inline emails
+			if inlineEmail && (paren > 0 || ltgt > 0 || bracket > 0) {
+				j--
+				emitUrl = true
+			}
 		}
 
 		// Heuristic to remove trailing characters that are
@@ -91,7 +106,7 @@ func HttpLinks(r io.Reader) (io.Reader, []string) {
 			continue
 		}
 		url := string(b[:j])
-		if match[2] == -1 && match[4] == -1 {
+		if inlineEmail {
 			// Email address with missing mailto: scheme. Add it.
 			url = "mailto:" + url
 		}
diff --git a/lib/parse/hyperlinks_test.go b/lib/parse/hyperlinks_test.go
index cedad648..00a06764 100644
--- a/lib/parse/hyperlinks_test.go
+++ b/lib/parse/hyperlinks_test.go
@@ -114,6 +114,26 @@ func TestHyperlinks(t *testing.T) {
 			text:  "You can reach me via the somewhat strange, but nonetheless valid, email mailto:~mpldr/list@[2001:db8::7]?subject=whazzup%3F",
 			links: []string{"mailto:~mpldr/list@[2001:db8::7]?subject=whazzup%3F"},
 		},
+		{
+			name:  "simple email in <a href>",
+			text:  `<a href="mailto:a@abc.com" rel="noopener noreferrer">`,
+			links: []string{"mailto:a@abc.com"},
+		},
+		{
+			name:  "simple email in <a> body",
+			text:  `<a href="#" rel="noopener noreferrer">a@abc.com</a><br/><p>more text</p>`,
+			links: []string{"mailto:a@abc.com"},
+		},
+		{
+			name:  "emails in <a> href and body",
+			text:  `<a href="mailto:a@abc.com" rel="noopener noreferrer">b@abc.com</a><br/><p>more text</p>`,
+			links: []string{"mailto:a@abc.com", "mailto:b@abc.com"},
+		},
+		{
+			name:  "email in &lt;...&gt;",
+			text:  `<div>01.02.2023, 10:11, "Firstname Lastname" &lt;a@abc.com&gt;:</div>`,
+			links: []string{"mailto:a@abc.com"},
+		},
 	}
 
 	for i, test := range tests {