Interpret newlines as line breaks when converting Markdown to HTML (#74)

src/message/html.rs

@@ -1027,9 +1027,8 @@ pub mod tests {
             Span::raw("│"),
             Span::raw("    "),
             Span::raw("│"),
-            Span::styled(" ", bold),
             Span::styled("3", bold),
-            Span::styled(" ", bold),
+            Span::styled("  ", bold),
             Span::raw("│")
         ]);
 
@@ -1157,4 +1156,21 @@ pub mod tests {
         assert_eq!(text.lines[1], Spans(vec![Span::raw("World"), Span::raw("  "),]));
         assert_eq!(text.lines[2], Spans(vec![Span::raw("Goodbye")]),);
     }
+
+    #[test]
+    fn test_embedded_newline() {
+        let s = "<p>Hello\nWorld</p>";
+        let tree = parse_matrix_html(s);
+        let text = tree.to_text(15, Style::default(), true);
+        assert_eq!(text.lines.len(), 1);
+        assert_eq!(
+            text.lines[0],
+            Spans(vec![
+                Span::raw("Hello"),
+                Span::raw(" "),
+                Span::raw("World"),
+                Span::raw("    ")
+            ])
+        );
+    }
 }

src/message/mod.rs

@@ -7,6 +7,7 @@ use std::hash::{Hash, Hasher};
 use std::slice::Iter;
 
 use chrono::{DateTime, Local as LocalTz, NaiveDateTime, TimeZone};
+use comrak::{markdown_to_html, ComrakOptions};
 use unicode_width::UnicodeWidthStr;
 
 use matrix_sdk::ruma::{
@@ -26,6 +27,7 @@ use matrix_sdk::ruma::{
                 Relation,
                 RoomMessageEvent,
                 RoomMessageEventContent,
+                TextMessageEventContent,
             },
             redaction::SyncRoomRedactionEvent,
         },
@@ -93,6 +95,19 @@ const USER_GUTTER_EMPTY_SPAN: Span<'static> = span_static(USER_GUTTER_EMPTY);
 const TIME_GUTTER_EMPTY: &str = "            ";
 const TIME_GUTTER_EMPTY_SPAN: Span<'static> = span_static(TIME_GUTTER_EMPTY);
 
+fn text_to_message_content(input: String) -> TextMessageEventContent {
+    let mut options = ComrakOptions::default();
+    options.render.hardbreaks = true;
+    let html = markdown_to_html(input.as_str(), &options);
+
+    TextMessageEventContent::html(input, html)
+}
+
+pub fn text_to_message(input: String) -> RoomMessageEventContent {
+    let msg = MessageType::Text(text_to_message_content(input));
+    RoomMessageEventContent::new(msg)
+}
+
 #[inline]
 fn millis_to_datetime(ms: UInt) -> DateTime<LocalTz> {
     let time = i64::from(ms) / 1000;
@@ -972,4 +987,48 @@ pub mod tests {
         // MessageCursor::latest() should point at the most recent message after conversion.
         assert_eq!(identity(&mc6), mc1);
     }
+
+    #[test]
+    fn test_markdown_message() {
+        let input = "**bold**\n";
+        let content = text_to_message_content(input.into());
+        assert_eq!(content.body, input);
+        assert_eq!(content.formatted.unwrap().body, "<p><strong>bold</strong></p>\n");
+
+        let input = "*emphasis*\n";
+        let content = text_to_message_content(input.into());
+        assert_eq!(content.body, input);
+        assert_eq!(content.formatted.unwrap().body, "<p><em>emphasis</em></p>\n");
+
+        let input = "`code`\n";
+        let content = text_to_message_content(input.into());
+        assert_eq!(content.body, input);
+        assert_eq!(content.formatted.unwrap().body, "<p><code>code</code></p>\n");
+
+        let input = "```rust\nconst A: usize = 1;\n```\n";
+        let content = text_to_message_content(input.into());
+        assert_eq!(content.body, input);
+        assert_eq!(
+            content.formatted.unwrap().body,
+            "<pre><code class=\"language-rust\">const A: usize = 1;\n</code></pre>\n"
+        );
+
+        let input = "para 1\n\npara 2\n";
+        let content = text_to_message_content(input.into());
+        assert_eq!(content.body, input);
+        assert_eq!(content.formatted.unwrap().body, "<p>para 1</p>\n<p>para 2</p>\n");
+
+        let input = "line 1\nline 2\n";
+        let content = text_to_message_content(input.into());
+        assert_eq!(content.body, input);
+        assert_eq!(content.formatted.unwrap().body, "<p>line 1<br />\nline 2</p>\n");
+
+        let input = "# Heading\n## Subheading\n\ntext\n";
+        let content = text_to_message_content(input.into());
+        assert_eq!(content.body, input);
+        assert_eq!(
+            content.formatted.unwrap().body,
+            "<h1>Heading</h1>\n<h2>Subheading</h2>\n<p>text</p>\n"
+        );
+    }
 }

src/message/printer.rs

@@ -156,8 +156,13 @@ impl<'a> TextPrinter<'a> {
     pub fn push_str(&mut self, s: &'a str, style: Style) {
         let style = self.base_style.patch(style);
 
-        for word in UnicodeSegmentation::split_word_bounds(s) {
-            if self.width == 0 && word.chars().all(char::is_whitespace) {
+        for mut word in UnicodeSegmentation::split_word_bounds(s) {
+            if let "\n" | "\r\n" = word {
+                // Render embedded newlines as spaces.
+                word = " ";
+            }
+
+            if self.curr_width == 0 && word.chars().all(char::is_whitespace) {
                 // Drop leading whitespace.
                 continue;
             }

src/windows/room/chat.rs

@@ -75,7 +75,7 @@ use crate::base::{
     SendAction,
 };
 
-use crate::message::{Message, MessageEvent, MessageKey, MessageTimeStamp};
+use crate::message::{text_to_message, Message, MessageEvent, MessageKey, MessageTimeStamp};
 use crate::worker::Requester;
 
 use super::scrollback::{Scrollback, ScrollbackState};
@@ -407,10 +407,7 @@ impl ChatState {
                     return Ok(None);
                 }
 
-                let msg = TextMessageEventContent::markdown(msg.to_string());
-                let msg = MessageType::Text(msg);
-
-                let mut msg = RoomMessageEventContent::new(msg);
+                let mut msg = text_to_message(msg.to_string());
 
                 if let Some((_, event_id)) = &self.editing {
                     msg.relates_to = Some(Relation::Replacement(Replacement::new(