Avoid moves when emitting code for String

sunchao · Dec 5, 2018 · 1f6d829 · 1f6d829
1 parent 3b0ae7a
commit 1f6d829
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Showing 2 changed files with 10 additions and 4 deletions.
diff --git a/parquet_derive/src/lib.rs b/parquet_derive/src/lib.rs
@@ -192,15 +192,14 @@ impl FieldInfo {
         // TODO: can this be lumped with str by doing Borrow<str>/AsRef<str> in the
         // ByteArray::from?
         "String" => {
-          // panic!("{:#?}", self);
           quote! {
             {
                 let definition_levels : Vec<i16> = self.iter().
-                        map(|x| x.#field_name).
+                        map(|x| &x.#field_name).
                         map(|y| if y.is_some() { 1 } else { 0 }).
                         collect();
                 let vals : Vec<parquet::data_type::ByteArray> = self.iter().
-                        map(|x| x.#field_name).
+                        map(|x| &x.#field_name).
                         filter_map(|z| {
                           if let Some(ref inner) = z {
                               Some((&inner[..]).into())

diff --git a/parquet_derive_test/src/lib.rs b/parquet_derive_test/src/lib.rs
@@ -12,12 +12,14 @@ struct ACompleteRecord<'a> {
   pub a_string: String,
   pub a_borrowed_string: &'a String,
   pub maybe_a_str: Option<&'a str>,
+  pub maybe_a_string: Option<String>,
   pub magic_number: i32,
   pub low_quality_pi: f32,
   pub high_quality_pi: f64,
   pub maybe_pi: Option<f32>,
   pub maybe_best_pi: Option<f64>,
   pub borrowed_maybe_a_string: &'a Option<String>,
+  pub borrowed_maybe_a_str: &'a Option<&'a str>,
 }
 
 #[cfg(test)]
@@ -42,12 +44,14 @@ mod tests {
             REQUIRED BINARY  a_string (UTF8);
             REQUIRED BINARY  a_borrowed_string (UTF8);
             OPTIONAL BINARY  a_maybe_str (UTF8);
+            OPTIONAL BINARY  a_maybe_string (UTF8);
             REQUIRED INT32   magic_number;
             REQUIRED FLOAT   low_quality_pi;
             REQUIRED DOUBLE  high_quality_pi;
             OPTIONAL FLOAT   maybe_pi;
             OPTIONAL DOUBLE  maybe_best_pi;
             OPTIONAL BINARY  borrowed_maybe_a_string (UTF8);
+            OPTIONAL BINARY  maybe_a_str (UTF8);
         }";
     let schema = Rc::new(parse_message_type(schema_str).unwrap());
 
@@ -56,20 +60,23 @@ mod tests {
 
     let a_str = "hello mother".to_owned();
     let a_borrowed_string = "cool news".to_owned();
-    let maybe_a_string = Some("it's true, I'm a string".into());
+    let maybe_a_string = Some("it's true, I'm a string".to_owned());
+    let maybe_a_str = Some(&a_str[..]);
 
     let drs: Vec<ACompleteRecord> = vec![ACompleteRecord {
       a_bool: true,
       a_str: &a_str[..],
       a_string: "hello father".into(),
       a_borrowed_string: &a_borrowed_string,
       maybe_a_str: Some(&a_str[..]),
+      maybe_a_string: Some(a_str.clone()),
       magic_number: 100,
       low_quality_pi: 3.14,
       high_quality_pi: 3.1415,
       maybe_pi: Some(3.14),
       maybe_best_pi: Some(3.1415),
       borrowed_maybe_a_string: &maybe_a_string,
+      borrowed_maybe_a_str: &maybe_a_str,
     }];
     let chunks = &drs[..];