[refactor] #3740: Replace impl From<Pagination> for Vec<...> with a m…

…ethod (#4023)

Signed-off-by: VAmuzing <[email protected]>

client/src/client.rs

@@ -387,8 +387,8 @@ impl QueryRequest {
 
         match self.request {
             iroha_data_model::query::QueryRequest::Query(query_with_params) => builder
-                .params(Vec::from(query_with_params.sorting().clone()))
-                .params(Vec::from(*query_with_params.pagination()))
+                .params(query_with_params.sorting().clone().into_query_parameters())
+                .params(query_with_params.pagination().into_query_parameters())
                 .body(query_with_params.query().clone()),
             iroha_data_model::query::QueryRequest::Cursor(cursor) => {
                 builder.params(Vec::from(cursor))
@@ -969,7 +969,7 @@ impl Client {
         retry_in: Duration,
         pagination: Pagination,
     ) -> Result<Option<SignedTransaction>> {
-        let pagination: Vec<_> = pagination.into();
+        let pagination = pagination.into_query_parameters();
         for _ in 0..retry_count {
             let response = DefaultRequestBuilder::new(
                 HttpMethod::GET,

data_model/src/query/pagination.rs

@@ -38,16 +38,22 @@ pub struct Pagination {
     pub start: Option<NonZeroU64>,
 }
 
-impl From<Pagination> for Vec<(&'static str, NonZeroU64)> {
-    fn from(pagination: Pagination) -> Self {
-        match (pagination.start, pagination.limit) {
+impl Pagination {
+    /// Converts self to iterator of tuples to be used in queries
+    ///
+    /// The length of the output iterator is not constant and it's in (0..3)
+    pub fn into_query_parameters(
+        self,
+    ) -> impl IntoIterator<Item = (&'static str, NonZeroU64)> + Clone {
+        let result_vec = match (self.start, self.limit) {
             (Some(start), Some(limit)) => {
                 vec![(PAGINATION_LIMIT, limit.into()), (PAGINATION_START, start)]
             }
             (Some(start), None) => vec![(PAGINATION_START, start)],
             (None, Some(limit)) => vec![(PAGINATION_LIMIT, limit.into())],
             (None, None) => Vec::new(),
-        }
+        };
+        result_vec.into_iter()
     }
 }
 

data_model/src/query/sorting.rs

@@ -38,13 +38,14 @@ impl Sorting {
     }
 }
 
-impl From<Sorting> for Vec<(&'static str, Name)> {
-    fn from(sorting: Sorting) -> Self {
-        if let Some(key) = sorting.sort_by_metadata_key {
-            return vec![(SORT_BY_KEY, key)];
-        }
-
-        Vec::new()
+impl Sorting {
+    /// Converts self to iterator of tuples to be used in queries
+    ///
+    /// The length of the output iterator is not constant and has either 0 or 1 value
+    pub fn into_query_parameters(self) -> impl IntoIterator<Item = (&'static str, Name)> + Clone {
+        self.sort_by_metadata_key
+            .map(|key| (SORT_BY_KEY, key))
+            .into_iter()
     }
 }