Remove markdown module from rust-analyzer crate

crates/ide-db/src/rust_doc.rs

@@ -1,5 +1,7 @@
 //! Rustdoc specific doc comment handling
 
+use crate::documentation::Documentation;
+
 // stripped down version of https://github.com/rust-lang/rust/blob/392ba2ba1a7d6c542d2459fb8133bebf62a4a423/src/librustdoc/html/markdown.rs#L810-L933
 pub fn is_rust_fence(s: &str) -> bool {
     let mut seen_rust_tags = false;
@@ -32,3 +34,170 @@ pub fn is_rust_fence(s: &str) -> bool {
 
     !seen_other_tags || seen_rust_tags
 }
+
+const RUSTDOC_FENCES: [&str; 2] = ["```", "~~~"];
+
+pub fn format_docs(src: &Documentation) -> String {
+    format_docs_(src.as_str())
+}
+
+fn format_docs_(src: &str) -> String {
+    let mut processed_lines = Vec::new();
+    let mut in_code_block = false;
+    let mut is_rust = false;
+
+    for mut line in src.lines() {
+        if in_code_block && is_rust && code_line_ignored_by_rustdoc(line) {
+            continue;
+        }
+
+        if let Some(header) = RUSTDOC_FENCES.into_iter().find_map(|fence| line.strip_prefix(fence))
+        {
+            in_code_block ^= true;
+
+            if in_code_block {
+                is_rust = is_rust_fence(header);
+
+                if is_rust {
+                    line = "```rust";
+                }
+            }
+        }
+
+        if in_code_block {
+            let trimmed = line.trim_start();
+            if is_rust && trimmed.starts_with("##") {
+                line = &trimmed[1..];
+            }
+        }
+
+        processed_lines.push(line);
+    }
+    processed_lines.join("\n")
+}
+
+fn code_line_ignored_by_rustdoc(line: &str) -> bool {
+    let trimmed = line.trim();
+    trimmed == "#" || trimmed.starts_with("# ") || trimmed.starts_with("#\t")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_format_docs_adds_rust() {
+        let comment = "```\nfn some_rust() {}\n```";
+        assert_eq!(format_docs_(comment), "```rust\nfn some_rust() {}\n```");
+    }
+
+    #[test]
+    fn test_format_docs_handles_plain_text() {
+        let comment = "```text\nthis is plain text\n```";
+        assert_eq!(format_docs_(comment), "```text\nthis is plain text\n```");
+    }
+
+    #[test]
+    fn test_format_docs_handles_non_rust() {
+        let comment = "```sh\nsupposedly shell code\n```";
+        assert_eq!(format_docs_(comment), "```sh\nsupposedly shell code\n```");
+    }
+
+    #[test]
+    fn test_format_docs_handles_rust_alias() {
+        let comment = "```ignore\nlet z = 55;\n```";
+        assert_eq!(format_docs_(comment), "```rust\nlet z = 55;\n```");
+    }
+
+    #[test]
+    fn test_format_docs_handles_complex_code_block_attrs() {
+        let comment = "```rust,no_run\nlet z = 55;\n```";
+        assert_eq!(format_docs_(comment), "```rust\nlet z = 55;\n```");
+    }
+
+    #[test]
+    fn test_format_docs_handles_error_codes() {
+        let comment = "```compile_fail,E0641\nlet b = 0 as *const _;\n```";
+        assert_eq!(format_docs_(comment), "```rust\nlet b = 0 as *const _;\n```");
+    }
+
+    #[test]
+    fn test_format_docs_skips_comments_in_rust_block() {
+        let comment =
+            "```rust\n # skip1\n# skip2\n#stay1\nstay2\n#\n #\n   #    \n #\tskip3\n\t#\t\n```";
+        assert_eq!(format_docs_(comment), "```rust\n#stay1\nstay2\n```");
+    }
+
+    #[test]
+    fn test_format_docs_does_not_skip_lines_if_plain_text() {
+        let comment =
+            "```text\n # stay1\n# stay2\n#stay3\nstay4\n#\n #\n   #    \n #\tstay5\n\t#\t\n```";
+        assert_eq!(
+            format_docs_(comment),
+            "```text\n # stay1\n# stay2\n#stay3\nstay4\n#\n #\n   #    \n #\tstay5\n\t#\t\n```",
+        );
+    }
+
+    #[test]
+    fn test_format_docs_keeps_comments_outside_of_rust_block() {
+        let comment = " # stay1\n# stay2\n#stay3\nstay4\n#\n #\n   #    \n #\tstay5\n\t#\t";
+        assert_eq!(format_docs_(comment), comment);
+    }
+
+    #[test]
+    fn test_format_docs_preserves_newlines() {
+        let comment = "this\nis\nmultiline";
+        assert_eq!(format_docs_(comment), comment);
+    }
+
+    #[test]
+    fn test_code_blocks_in_comments_marked_as_rust() {
+        let comment = r#"```rust
+fn main(){}
+```
+Some comment.
+```
+let a = 1;
+```"#;
+
+        assert_eq!(
+            format_docs_(comment),
+            "```rust\nfn main(){}\n```\nSome comment.\n```rust\nlet a = 1;\n```"
+        );
+    }
+
+    #[test]
+    fn test_code_blocks_in_comments_marked_as_text() {
+        let comment = r#"```text
+filler
+text
+```
+Some comment.
+```
+let a = 1;
+```"#;
+
+        assert_eq!(
+            format_docs_(comment),
+            "```text\nfiller\ntext\n```\nSome comment.\n```rust\nlet a = 1;\n```"
+        );
+    }
+
+    #[test]
+    fn test_format_docs_handles_escape_double_hashes() {
+        let comment = r#"```rust
+let s = "foo
+## bar # baz";
+```"#;
+
+        assert_eq!(format_docs_(comment), "```rust\nlet s = \"foo\n# bar # baz\";\n```");
+    }
+
+    #[test]
+    fn test_format_docs_handles_double_hashes_non_rust() {
+        let comment = r#"```markdown
+## A second-level heading
+```"#;
+        assert_eq!(format_docs_(comment), "```markdown\n## A second-level heading\n```");
+    }
+}