1 files changed, 106 insertions, 0 deletions

diff --git a/crates/ra_ide/src/syntax_highlighting/html.rs b/crates/ra_ide/src/syntax_highlighting/html.rs
new file mode 100644
index 000000000..e13766c9d
--- /dev/null
+++ b/crates/ra_ide/src/syntax_highlighting/html.rs
@@ -0,0 +1,106 @@
+//! Renders a bit of code as HTML.
+
+use ra_db::SourceDatabase;
+use ra_syntax::AstNode;
+
+use crate::{FileId, HighlightedRange, RootDatabase};
+
+use super::highlight;
+
+pub(crate) fn highlight_as_html(db: &RootDatabase, file_id: FileId, rainbow: bool) -> String {
+    let parse = db.parse(file_id);
+
+    fn rainbowify(seed: u64) -> String {
+        use rand::prelude::*;
+        let mut rng = SmallRng::seed_from_u64(seed);
+        format!(
+            "hsl({h},{s}%,{l}%)",
+            h = rng.gen_range::<u16, _, _>(0, 361),
+            s = rng.gen_range::<u16, _, _>(42, 99),
+            l = rng.gen_range::<u16, _, _>(40, 91),
+        )
+    }
+
+    let mut ranges = highlight(db, file_id, None);
+    ranges.sort_by_key(|it| it.range.start());
+    // quick non-optimal heuristic to intersect token ranges and highlighted ranges
+    let mut frontier = 0;
+    let mut could_intersect: Vec<&HighlightedRange> = Vec::new();
+
+    let mut buf = String::new();
+    buf.push_str(&STYLE);
+    buf.push_str("<pre><code>");
+    let tokens = parse.tree().syntax().descendants_with_tokens().filter_map(|it| it.into_token());
+    for token in tokens {
+        could_intersect.retain(|it| token.text_range().start() <= it.range.end());
+        while let Some(r) = ranges.get(frontier) {
+            if r.range.start() <= token.text_range().end() {
+                could_intersect.push(r);
+                frontier += 1;
+            } else {
+                break;
+            }
+        }
+        let text = html_escape(&token.text());
+        let ranges = could_intersect
+            .iter()
+            .filter(|it| token.text_range().is_subrange(&it.range))
+            .collect::<Vec<_>>();
+        if ranges.is_empty() {
+            buf.push_str(&text);
+        } else {
+            let classes = ranges
+                .iter()
+                .map(|it| it.highlight.to_string().replace('.', " "))
+                .collect::<Vec<_>>()
+                .join(" ");
+            let binding_hash = ranges.first().and_then(|x| x.binding_hash);
+            let color = match (rainbow, binding_hash) {
+                (true, Some(hash)) => format!(
+                    " data-binding-hash=\"{}\" style=\"color: {};\"",
+                    hash,
+                    rainbowify(hash)
+                ),
+                _ => "".into(),
+            };
+            buf.push_str(&format!("<span class=\"{}\"{}>{}</span>", classes, color, text));
+        }
+    }
+    buf.push_str("</code></pre>");
+    buf
+}
+
+//FIXME: like, real html escaping
+fn html_escape(text: &str) -> String {
+    text.replace("<", "&lt;").replace(">", "&gt;")
+}
+
+const STYLE: &str = "
+<style>
+body                { margin: 0; }
+pre                 { color: #DCDCCC; background: #3F3F3F; font-size: 22px; padding: 0.4em; }
+
+.lifetime           { color: #DFAF8F; font-style: italic; }
+.comment            { color: #7F9F7F; }
+.struct, .enum      { color: #7CB8BB; }
+.enum_variant       { color: #BDE0F3; }
+.string_literal     { color: #CC9393; }
+.field              { color: #94BFF3; }
+.function           { color: #93E0E3; }
+.parameter          { color: #94BFF3; }
+.text               { color: #DCDCCC; }
+.type               { color: #7CB8BB; }
+.builtin_type       { color: #8CD0D3; }
+.type_param         { color: #DFAF8F; }
+.attribute          { color: #94BFF3; }
+.numeric_literal    { color: #BFEBBF; }
+.macro              { color: #94BFF3; }
+.module             { color: #AFD8AF; }
+.variable           { color: #DCDCCC; }
+.mutable            { text-decoration: underline; }
+
+.keyword            { color: #F0DFAF; font-weight: bold; }
+.keyword.unsafe     { color: #BC8383; font-weight: bold; }
+.control            { font-style: italic; }
+</style>
+";