Merge pull request #108 from olvyko/add-skip-ser-if

Add skip_serializing_if support for attributes

yaserde/tests/skip_if.rs

@@ -62,3 +62,60 @@ fn skip_serializing_if_for_struct() {
   let content = "<base />";
   serialize_and_validate!(model, content);
 }
+
+#[test]
+fn skip_serializing_if_for_struct_attributes() {
+  init();
+
+  fn default_string_function() -> String {
+    "mask_default".to_string()
+  }
+
+  #[derive(YaSerialize, PartialEq, Debug)]
+  #[yaserde(rename = "base")]
+  pub struct XmlStruct {
+    #[yaserde(
+      attribute,
+      skip_serializing_if = "check_string_function",
+      default = "default_string_function"
+    )]
+    string_with_default_item: String,
+    #[yaserde(attribute, skip_serializing_if = "check_string_function")]
+    string_item: String,
+    #[yaserde(attribute, skip_serializing_if = "check_bool_function")]
+    bool_item: bool,
+    #[yaserde(attribute, skip_serializing_if = "check_f32_function")]
+    f32_item: f32,
+    #[yaserde(attribute, skip_serializing_if = "check_option_string_function")]
+    option_string_item: Option<String>,
+  }
+
+  impl XmlStruct {
+    fn check_string_function(&self, value: &str) -> bool {
+      value == "something"
+    }
+
+    fn check_option_string_function(&self, value: &Option<String>) -> bool {
+      value == &Some("something".to_string())
+    }
+
+    fn check_bool_function(&self, value: &bool) -> bool {
+      value == &true
+    }
+
+    fn check_f32_function(&self, value: &f32) -> bool {
+      (value - 0.0).abs() < std::f32::EPSILON
+    }
+  }
+
+  let model = XmlStruct {
+    string_with_default_item: "mask_default".to_string(),
+    string_item: "something".to_string(),
+    bool_item: true,
+    f32_item: 0.0,
+    option_string_item: Some("something".to_string()),
+  };
+
+  let content = "<base />";
+  serialize_and_validate!(model, content);
+}

yaserde_derive/src/common/field.rs

@@ -145,13 +145,18 @@ impl YaSerdeField {
       .map(|builder| quote!(let yaserde_inner = #builder;))
       .unwrap_or_default();
 
+    let skip_if = self
+      .get_skip_serializing_if_function()
+      .map(|skip_if_function| quote!(!self.#skip_if_function(&self.#label)))
+      .unwrap_or(quote!(true));
+
     self
       .get_default_function()
       .map(|default_function| {
         quote! {
           #yaserde_inner_definition
           let struct_start_event =
-            if self.#label != #default_function() {
+            if #skip_if && self.#label != #default_function() {
               #setter
             } else {
               struct_start_event
@@ -160,7 +165,7 @@ impl YaSerdeField {
       })
       .unwrap_or(quote! {
         #yaserde_inner_definition
-        let struct_start_event = #setter;
+        let struct_start_event = if #skip_if { #setter } else { struct_start_event };
       })
   }
 }