Merge #6750

6750: Remove documentation query, move doc handling to attributes r=matklad a=Veykril

Fixes #3182

Removes the documentation query in favor of `Attrs::docs`. Attrs already handlded doc comments partially but the alloc saving check was wrong so it only worked when other attributes existed as well. Unfortunately the `new` constructor has to do an intermediate allocation now because we need to keep the order of mixed doc attributes and doc comments.

I've also partially adjusted the `hover` module to have its tests check the changes, it still has some `HasSource` trait usage due to the `ShortLabel` trait usage, as that is only implemented on the Ast parts and not the Hir, should this ideally be implemented for the Hir types as well?(would be a follow up PR of course)

Co-authored-by: Lukas Wirth <[email protected]>

2 files changed, 32 insertions, 33 deletions

diff --git a/crates/syntax/src/ast/token_ext.rs b/crates/syntax/src/ast/token_ext.rs
index fa40e64e8..a10b14778 100644
--- a/crates/syntax/src/ast/token_ext.rs
+++ b/crates/syntax/src/ast/token_ext.rs
@@ -24,6 +24,28 @@ impl ast::Comment {
             .unwrap();
         prefix
     }
+
+    /// Returns the textual content of a doc comment block as a single string.
+    /// That is, strips leading `///` (+ optional 1 character of whitespace),
+    /// trailing `*/`, trailing whitespace and then joins the lines.
+    pub fn doc_comment(&self) -> Option<&str> {
+        let kind = self.kind();
+        match kind {
+            CommentKind { shape, doc: Some(_) } => {
+                let prefix = kind.prefix();
+                let text = &self.text().as_str()[prefix.len()..];
+                let ws = text.chars().next().filter(|c| c.is_whitespace());
+                let text = ws.map_or(text, |ws| &text[ws.len_utf8()..]);
+                match shape {
+                    CommentShape::Block if text.ends_with("*/") => {
+                        Some(&text[..text.len() - "*/".len()])
+                    }
+                    _ => Some(text),
+                }
+            }
+            _ => None,
+        }
+    }
 }
 
 #[derive(Debug, PartialEq, Eq, Clone, Copy)]
@@ -73,6 +95,11 @@ impl CommentKind {
             .unwrap();
         kind
     }
+
+    fn prefix(&self) -> &'static str {
+        let &(prefix, _) = CommentKind::BY_PREFIX.iter().find(|(_, kind)| kind == self).unwrap();
+        prefix
+    }
 }
 
 impl ast::Whitespace {
diff --git a/crates/syntax/src/ast/traits.rs b/crates/syntax/src/ast/traits.rs
index 0bdc22d95..13a769d51 100644
--- a/crates/syntax/src/ast/traits.rs
+++ b/crates/syntax/src/ast/traits.rs
@@ -91,40 +91,12 @@ impl CommentIter {
     /// That is, strips leading `///` (+ optional 1 character of whitespace),
     /// trailing `*/`, trailing whitespace and then joins the lines.
     pub fn doc_comment_text(self) -> Option<String> {
-        let mut has_comments = false;
-        let docs = self
-            .filter(|comment| comment.kind().doc.is_some())
-            .map(|comment| {
-                has_comments = true;
-                let prefix_len = comment.prefix().len();
-
-                let line: &str = comment.text().as_str();
-
-                // Determine if the prefix or prefix + 1 char is stripped
-                let pos =
-                    if let Some(ws) = line.chars().nth(prefix_len).filter(|c| c.is_whitespace()) {
-                        prefix_len + ws.len_utf8()
-                    } else {
-                        prefix_len
-                    };
-
-                let end = if comment.kind().shape.is_block() && line.ends_with("*/") {
-                    line.len() - 2
-                } else {
-                    line.len()
-                };
-
-                // Note that we do not trim the end of the line here
-                // since whitespace can have special meaning at the end
-                // of a line in markdown.
-                line[pos..end].to_owned()
-            })
-            .join("\n");
-
-        if has_comments {
-            Some(docs)
-        } else {
+        let docs =
+            self.filter_map(|comment| comment.doc_comment().map(ToOwned::to_owned)).join("\n");
+        if docs.is_empty() {
             None
+        } else {
+            Some(docs)
         }
     }
 }