Use i32 instead of usize for bson document

The generic Coords is waiting  on reoslution for: rust-lang/rust#49415

Author: tobz1000

src/coords.rs

@@ -1,28 +1,29 @@
 use std::fmt;
+use std::convert::{TryFrom, TryInto};
 
 #[derive(Clone, Serialize, Deserialize)]
-pub struct Coords(pub Vec<usize>);
+pub struct Coords<T = usize>(pub Vec<T>);
 
-impl Coords {
+impl<T> Coords<T>
+    where T: TryFrom<usize> + TryInto<usize>,
+          <T as TryFrom<usize>>::Error: fmt::Debug,
+          <T as TryInto<usize>>::Error: fmt::Debug,
+{
     pub fn from_index(index: usize, dims: &[usize]) -> Self {
-        let mut coords = vec![0; dims.len()];
-        let mut remainder = index;
-
-        for i in (0..dims.len()).rev() {
-            coords[i] = remainder % dims[i];
-            remainder /= dims[i];
-        }
-
-        Coords(coords)
+        Coords(dims.iter().scan(index, |remainder, &dim| {
+            let coord = T::try_from(*remainder % dim).unwrap();
+            *remainder /= dim;
+            Some(coord)
+        }).collect())
     }
 
     pub fn to_index(&self, dims: &[usize]) -> usize {
         self.0.iter().zip(dims.iter())
-            .fold(0, |acc, (&coord, &dim)| (acc * dim) + coord)
+            .fold(0, |acc, (&coord, &dim)| (acc * dim) + coord.try_into().unwrap())
     }
 }
 
-impl fmt::Debug for Coords {
+impl<T: fmt::Debug> fmt::Debug for Coords<T> {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         self.0.fmt(f)
     }

src/server/db.rs

@@ -17,7 +17,7 @@ pub enum CellState { Empty, Cleared, Mine }
 pub struct CellInfo {
     pub surrounding: usize,
     pub state: CellState,
-    pub coords: Coords
+    pub coords: Coords<i32>
 }
 
 #[derive(Serialize, Deserialize)]
@@ -27,10 +27,10 @@ pub struct Game {
     pub id: Option<ObjectId>,
     pub created_at: DateTime<Utc>,
     pub pass: Option<String>,
-    pub seed: u32,
-    pub dims: Vec<usize>,
-    pub size: usize,
-    pub mines: usize,
+    pub seed: i32,
+    pub dims: Vec<i32>,
+    pub size: i32,
+    pub mines: i32,
     pub autoclear: bool,
     pub turns: Vec<Turn>,
     pub clients: Vec<String>,
@@ -42,20 +42,20 @@ pub struct Game {
 #[serde(rename_all = "camelCase")]
 pub struct Turn {
     pub turn_taken_at: DateTime<Utc>,
-    pub clear_req: Vec<Coords>,
+    pub clear_req: Vec<Coords<i32>>,
     pub clear_actual: Vec<CellInfo>,
-    pub flagged: Vec<Coords>,
-    pub unflagged: Vec<Coords>,
+    pub flagged: Vec<Coords<i32>>,
+    pub unflagged: Vec<Coords<i32>>,
     pub game_over: bool,
     pub win: bool,
-    pub cells_rem: usize,
+    pub cells_rem: i32,
 }
 
 impl<'a> Model<'a> for Game {
     const COLLECTION_NAME: &'static str = "games";
 
     fn id(&self) -> Option<ObjectId> {
-        return self.id.clone();
+        self.id.clone()
     }
 
     fn set_id(&mut self, oid: ObjectId) {

src/server/native_server.rs

@@ -67,7 +67,7 @@ struct TurnInfo {
 
 impl TurnInfo {
     fn to_document(&self, server: &NativeServer) -> db::Turn {
-        let to_coords_vec = |indices: &[usize]| {
+        let to_coords_vec = |indices: &[usize]| -> Vec<Coords<i32>> {
             indices.iter()
                 .map(|&i| Coords::from_index(i, &server.dims))
                 .collect()
@@ -103,7 +103,7 @@ impl TurnInfo {
             unflagged: to_coords_vec(&self.unflagged),
             game_over: self.game_state != GameState::Ongoing,
             win: self.game_state == GameState::Win,
-            cells_rem: self.cells_rem
+            cells_rem: self.cells_rem as i32
         }
     }
 }
@@ -271,10 +271,10 @@ impl NativeServer {
             id: None,
             created_at,
             pass: None,
-            seed,
-            dims: dims.clone(),
-            size: dims.iter().fold(1, |acc, &d| acc * d),
-            mines,
+            seed: seed as i32,
+            dims: dims.iter().map(|&d| d as i32).collect(),
+            size: dims.iter().fold(1, |acc, &d| acc * d) as i32,
+            mines: mines as i32,
             autoclear,
             turns,
             clients: vec!["RustoBusto".to_owned()],