TextInputStream: don't ignore unterminated last line

NEWS

@@ -1,5 +1,6 @@
 ver 0.19.2 (not yet released)
 * playlist
+  - m3u: don't ignore unterminated last line
   - m3u: recognize the file suffix ".m3u8"
 * decoder
   - faad: remove workaround for ancient libfaad2 ABI bug

src/input/TextInputStream.cxx

@@ -38,8 +38,8 @@ TextInputStream::ReadLine()
 	while (true) {
 		auto dest = buffer.Write();
 		if (dest.size < 2) {
-			/* end of file (or line too long): terminate
-			   the current line */
+			/* line too long: terminate the current
+			   line */
 
 			assert(!dest.IsEmpty());
 			dest[0] = 0;
@@ -66,7 +66,19 @@ TextInputStream::ReadLine()
 		if (line != nullptr)
 			return line;
 
-		if (nbytes == 0)
-			return nullptr;
+		if (nbytes == 0) {
+			/* end of file: see if there's an unterminated
+			   line */
+
+			dest = buffer.Write();
+			assert(!dest.IsEmpty());
+			dest[0] = 0;
+
+			auto r = buffer.Read();
+			buffer.Clear();
+			return r.IsEmpty()
+				? nullptr
+				: r.data;
+		}
 	}
 }