Support multiple attributes

prost-build/src/code_generator.rs

@@ -253,9 +253,11 @@ impl<'a> CodeGenerator<'a> {
         assert_eq!(b'.', fq_message_name.as_bytes()[0]);
         // TODO: this clone is dirty, but expedious.
         if let Some(attributes) = self.config.type_attributes.get(fq_message_name).cloned() {
-            self.push_indent();
-            self.buf.push_str(&attributes);
-            self.buf.push('\n');
+            for attribute in attributes {
+                self.push_indent();
+                self.buf.push_str(&attribute);
+                self.buf.push('\n');
+            }
         }
     }
 
@@ -268,9 +270,11 @@ impl<'a> CodeGenerator<'a> {
             .get_field(fq_message_name, field_name)
             .cloned()
         {
-            self.push_indent();
-            self.buf.push_str(&attributes);
-            self.buf.push('\n');
+            for attribute in attributes {
+                self.push_indent();
+                self.buf.push_str(&attribute);
+                self.buf.push('\n');
+            }
         }
     }
 

prost-build/src/lib.rs

@@ -224,8 +224,8 @@ pub struct Config {
     service_generator: Option<Box<dyn ServiceGenerator>>,
     map_type: PathMap<MapType>,
     bytes_type: PathMap<BytesType>,
-    type_attributes: PathMap<String>,
-    field_attributes: PathMap<String>,
+    type_attributes: PathMap<Vec<String>>,
+    field_attributes: PathMap<Vec<String>>,
     prost_types: bool,
     strip_enum_prefix: bool,
     out_dir: Option<PathBuf>,
@@ -391,7 +391,7 @@ impl Config {
         A: AsRef<str>,
     {
         self.field_attributes
-            .insert(path.as_ref().to_string(), attribute.as_ref().to_string());
+            .extend(path.as_ref().to_string(), attribute.as_ref().to_string());
         self
     }
 
@@ -440,7 +440,7 @@ impl Config {
         A: AsRef<str>,
     {
         self.type_attributes
-            .insert(path.as_ref().to_string(), attribute.as_ref().to_string());
+            .extend(path.as_ref().to_string(), attribute.as_ref().to_string());
         self
     }
 

prost-build/src/path.rs

@@ -58,6 +58,16 @@ impl<T> PathMap<T> {
     }
 }
 
+impl<T> PathMap<Vec<T>> {
+    /// Inserts a new associated value to the current matchers values.
+    pub(crate) fn extend(&mut self, matcher: String, value: T) {
+        self.matchers
+            .entry(matcher)
+            .or_insert_with(|| vec![])
+            .push(value);
+    }
+}
+
 /// Given a fully-qualified path, returns a sequence of fully-qualified paths which match a prefix
 /// of the input path, in decreasing path-length order.
 ///