Refactoring of schemars_derive

schemars_derive/src/attr/doc.rs

@@ -0,0 +1,65 @@
+use syn::{Attribute, Lit::Str, Meta::NameValue, MetaNameValue};
+
+pub fn get_title_and_desc_from_doc(attrs: &[Attribute]) -> (Option<String>, Option<String>) {
+    let doc = match get_doc(attrs) {
+        None => return (None, None),
+        Some(doc) => doc,
+    };
+
+    if doc.starts_with('#') {
+        let mut split = doc.splitn(2, '\n');
+        let title = split
+            .next()
+            .unwrap()
+            .trim_start_matches('#')
+            .trim()
+            .to_owned();
+        let maybe_desc = split.next().and_then(merge_description_lines);
+        (none_if_empty(title), maybe_desc)
+    } else {
+        (None, merge_description_lines(&doc))
+    }
+}
+
+fn merge_description_lines(doc: &str) -> Option<String> {
+    let desc = doc
+        .trim()
+        .split("\n\n")
+        .filter_map(|line| none_if_empty(line.trim().replace('\n', " ")))
+        .collect::<Vec<_>>()
+        .join("\n\n");
+    none_if_empty(desc)
+}
+
+fn get_doc(attrs: &[Attribute]) -> Option<String> {
+    let doc = attrs
+        .iter()
+        .filter_map(|attr| {
+            if !attr.path.is_ident("doc") {
+                return None;
+            }
+
+            let meta = attr.parse_meta().ok()?;
+            if let NameValue(MetaNameValue { lit: Str(s), .. }) = meta {
+                return Some(s.value());
+            }
+
+            None
+        })
+        .collect::<Vec<_>>()
+        .iter()
+        .flat_map(|a| a.split('\n'))
+        .map(str::trim)
+        .skip_while(|s| *s == "")
+        .collect::<Vec<_>>()
+        .join("\n");
+    none_if_empty(doc)
+}
+
+fn none_if_empty(s: String) -> Option<String> {
+    if s.is_empty() {
+        None
+    } else {
+        Some(s)
+    }
+}