Add support for inputs with line breaks

Author: axelchalon

src/lib.rs

@@ -601,7 +601,27 @@ impl<'a> WrapIterImpl<'a> {
         while let Some((idx, ch)) = self.char_indices.next() {
             let char_width = ch.width().unwrap_or(0);
             let char_len = ch.len_utf8();
-            if is_whitespace(ch) {
+
+            if ch == '\n' {
+                self.split = idx;
+                self.split_len = char_len;
+                self.line_width_at_split = self.line_width;
+                self.in_whitespace = false;
+
+                // If this is not the final line, return the current line. Otherwise,
+                // we will return the line with its line break after exiting the loop
+                if self.split + self.split_len < self.source.len() {
+                    let mut line = self.create_result_line(wrapper);
+                    cow_add_assign(&mut line, &self.source[self.start..self.split]);
+
+                    self.start = self.split + self.split_len;
+                    self.line_width += wrapper.subsequent_indent.width();
+                    self.line_width -= self.line_width_at_split;
+
+                    return Some(line);
+                }
+            }
+            else if is_whitespace(ch) {
                 // Extend the previous split or create a new one.
                 if self.in_whitespace {
                     self.split_len += char_len;
@@ -1215,4 +1235,24 @@ mod tests {
                      "  bar"];
         assert_eq!(dedent(&add_nl(&x)), add_nl(&y));
     }
+
+    #[test]
+    fn multiline() {
+        assert_eq!(fill("1 3 5 7\n1 3 5 7",11),"1 3 5 7\n1 3 5 7");
+        assert_eq!(fill("1 3 5 7\n1 3 5 7",5),"1 3 5\n7\n1 3 5\n7");
+        assert_eq!(fill("1 3 5 7\n1 3 5 7",6),"1 3 5\n7\n1 3 5\n7");
+        assert_eq!(fill("1 3 5 7\nabcdefghi k",5),"1 3 5\n7\nabcde\nfghi\nk");
+        assert_eq!(fill("abcdefgh\ni k",5),"abcde\nfgh\ni k");
+        assert_eq!(fill("abcdefgh\nijklmnop",5),"abcde\nfgh\nijklm\nnop");
+
+        assert_eq!(fill("test\n",11),"test\n");
+        assert_eq!(fill("test\na",11),"test\na");
+        assert_eq!(fill("test\na\n",11),"test\na\n");
+        assert_eq!(fill("test\n\na\n\n",11),"test\n\na\n\n");
+        assert_eq!(fill("test\n\nabcdefghijk\n\nabcdefghijkm",11),"test\n\nabcdefghijk\n\nabcdefghijk\nm");
+        assert_eq!(fill("test\nabcdefghi\n",11),"test\nabcdefghi\n");
+        assert_eq!(fill("test\nabcdefghi\n\n",11),"test\nabcdefghi\n\n");
+        assert_eq!(fill("test\nabcdefghijklmnopq\n\n",11),"test\nabcdefghijk\nlmnopq\n\n");
+        assert_eq!(fill("test\nabcdefghijklmnopq abcdefghijk\n\n",11),"test\nabcdefghijk\nlmnopq\nabcdefghijk\n\n");
+    }
 }