Resolve rust clippy warnings (#946)

* refactor: avoid using `collect()` when not needed
and cascade notation

* refactor:  The user might expect to be able
to use Default as the type can be
constructed without arguments.

* refactor: using `clone` on type `indextree::NodeId`
which implements the `Copy` trait

* refactor: remove intermediary
variables and use cascade notation

* refactor: using `clone` on type `indextree::NodeId`
which implements the `Copy` trait

* refactor: unneeded `return` statement

* refactor: ok_or_else avoids executing a
function when it's not needed

* refactor: dereferenced by the compiler

* refactor: user enumeration for index

* refactor: using `clone` on type `usize`
 which implements the `Copy` trait

* refactor: useless conversion to the
same type: `&str`

* refactor:  The user might expect to be able use Default
as type can be constructed without arguments

* refactor:  The user might expect to be able use Default
as type can be constructed without arguments

* fix: rust formating with fmt

* fix: conflict default implementation

Co-authored-by: appflowy <annie@appflowy.io>

frontend/rust-lib/flowy-grid/src/services/group/configuration.rs

@@ -285,10 +285,11 @@ fn merge_groups(old_groups: &[GroupRevision], groups: Vec<Group>) -> MergeGroupR
     }
 
     // Find out the new groups
-    let new_groups = group_map.into_values();
-    for (index, group) in new_groups.into_iter().enumerate() {
-        merge_result.add_insert_group(index, group);
-    }
+    group_map
+        .into_values()
+        .enumerate()
+        .for_each(|(index, group)| merge_result.add_insert_group(index, group));
+
     merge_result
 }
 

shared-lib/lib-ot/src/core/document/attributes.rs

@@ -3,6 +3,12 @@ use std::collections::HashMap;
 #[derive(Clone, serde::Serialize, serde::Deserialize)]
 pub struct NodeAttributes(pub HashMap<String, Option<String>>);
 
+impl Default for NodeAttributes {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl NodeAttributes {
     pub fn new() -> NodeAttributes {
         NodeAttributes(HashMap::new())

shared-lib/lib-ot/src/core/document/document.rs

@@ -10,10 +10,16 @@ pub struct DocumentTree {
     pub root: NodeId,
 }
 
+impl Default for DocumentTree {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
 impl DocumentTree {
     pub fn new() -> DocumentTree {
         let mut arena = Arena::new();
-        let root = arena.new_node(NodeData::new("root".into()));
+        let root = arena.new_node(NodeData::new("root"));
         DocumentTree { arena, root }
     }
 
@@ -25,7 +31,7 @@ impl DocumentTree {
         let mut iterate_node = self.root;
 
         for id in &position.0 {
-            let child = self.child_at_index_of_path(iterate_node, id.clone());
+            let child = self.child_at_index_of_path(iterate_node, *id);
             iterate_node = match child {
                 Some(node) => node,
                 None => return None,
@@ -74,13 +80,10 @@ impl DocumentTree {
     fn child_at_index_of_path(&self, at_node: NodeId, index: usize) -> Option<NodeId> {
         let children = at_node.children(&self.arena);
 
-        let mut counter = 0;
-        for child in children {
+        for (counter, child) in children.enumerate() {
             if counter == index {
                 return Some(child);
             }
-
-            counter += 1;
         }
 
         None
@@ -107,7 +110,7 @@ impl DocumentTree {
         let last_index = path.0[path.0.len() - 1];
         let parent_node = self
             .node_at_path(&Position(parent_path.to_vec()))
-            .ok_or(ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
+            .ok_or_else(|| ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
 
         self.insert_child_at_index(parent_node, last_index, nodes.as_ref())
     }
@@ -132,7 +135,7 @@ impl DocumentTree {
 
         let node_to_insert = self
             .child_at_index_of_path(parent, index)
-            .ok_or(ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
+            .ok_or_else(|| ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
 
         self.insert_subtree_before(&node_to_insert, insert_children);
         Ok(())
@@ -160,11 +163,11 @@ impl DocumentTree {
     fn apply_update(&mut self, path: &Position, attributes: &NodeAttributes) -> Result<(), OTError> {
         let update_node = self
             .node_at_path(path)
-            .ok_or(ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
+            .ok_or_else(|| ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
         let node_data = self.arena.get_mut(update_node).unwrap();
         let new_node = {
             let old_attributes = &node_data.get().attributes;
-            let new_attributes = NodeAttributes::compose(&old_attributes, attributes);
+            let new_attributes = NodeAttributes::compose(old_attributes, attributes);
             NodeData {
                 attributes: new_attributes,
                 ..node_data.get().clone()
@@ -177,7 +180,7 @@ impl DocumentTree {
     fn apply_delete(&mut self, path: &Position, len: usize) -> Result<(), OTError> {
         let mut update_node = self
             .node_at_path(path)
-            .ok_or(ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
+            .ok_or_else(|| ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
         for _ in 0..len {
             let next = update_node.following_siblings(&self.arena).next();
             update_node.remove_subtree(&mut self.arena);
@@ -193,7 +196,7 @@ impl DocumentTree {
     fn apply_text_edit(&mut self, path: &Position, delta: &TextDelta) -> Result<(), OTError> {
         let edit_node = self
             .node_at_path(path)
-            .ok_or(ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
+            .ok_or_else(|| ErrorBuilder::new(OTErrorCode::PathNotFound).build())?;
         let node_data = self.arena.get_mut(edit_node).unwrap();
         let new_delta = if let Some(old_delta) = &node_data.get().delta {
             Some(old_delta.compose(delta)?)

shared-lib/lib-ot/src/core/document/position.rs

@@ -35,7 +35,8 @@ impl Position {
             prefix.push(b_at_index);
         }
         prefix.append(&mut suffix);
-        return Position(prefix);
+
+        Position(prefix)
     }
 }
 

shared-lib/lib-ot/src/core/document/transaction.rs

@@ -63,7 +63,7 @@ impl<'a> TransactionBuilder<'a> {
         let mut deleted_nodes: Vec<Box<NodeSubTree>> = Vec::new();
 
         for _ in 0..length {
-            deleted_nodes.push(self.get_deleted_nodes(node.clone()));
+            deleted_nodes.push(self.get_deleted_nodes(node));
             node = node.following_siblings(&self.document.arena).next().unwrap();
         }
 
@@ -74,19 +74,12 @@ impl<'a> TransactionBuilder<'a> {
     }
 
     fn get_deleted_nodes(&self, node_id: NodeId) -> Box<NodeSubTree> {
-        let node = self.document.arena.get(node_id.clone()).unwrap();
-        let node_data = node.get();
-        let mut children: Vec<Box<NodeSubTree>> = vec![];
+        let node_data = self.document.arena.get(node_id).unwrap().get();
 
-        let mut children_iterators = node_id.children(&self.document.arena);
-        loop {
-            let next_child = children_iterators.next();
-            if let Some(child_id) = next_child {
-                children.push(self.get_deleted_nodes(child_id));
-            } else {
-                break;
-            }
-        }
+        let mut children: Vec<Box<NodeSubTree>> = vec![];
+        node_id.children(&self.document.arena).for_each(|child_id| {
+            children.push(self.get_deleted_nodes(child_id));
+        });
 
         Box::new(NodeSubTree {
             node_type: node_data.node_type.clone(),