Use BTreeMap and BTreeSet in addition to HashMap and HashSet. (#327)

The main problem with HashMap and HashSet is that those are unordered. So we get results in different order each time.

Using BTreeMap and BTreeSet we will get the results in the same order each time.

Author: Meir Shpilraien (Spielrein)

examples/response.rs

@@ -2,7 +2,7 @@ use redis_module::{
     redis_module, redisvalue::RedisValueKey, Context, NextArg, RedisError, RedisResult,
     RedisString, RedisValue,
 };
-use std::collections::{HashMap, HashSet};
+use std::collections::{BTreeMap, BTreeSet};
 
 fn map_mget(ctx: &Context, args: Vec<RedisString>) -> RedisResult {
     if args.len() < 2 {
@@ -19,14 +19,14 @@ fn map_mget(ctx: &Context, args: Vec<RedisString>) -> RedisResult {
     let res = match values {
         None => RedisValue::Null,
         Some(values) => {
-            let mut map: HashMap<RedisValueKey, RedisValue> = HashMap::with_capacity(fields.len());
+            let mut map: BTreeMap<RedisValueKey, RedisValue> = BTreeMap::new();
             for (field, value) in values.into_iter() {
                 map.insert(
                     RedisValueKey::BulkRedisString(field),
                     RedisValue::BulkRedisString(value),
                 );
             }
-            RedisValue::Map(map)
+            RedisValue::OrderedMap(map)
         }
     };
 
@@ -48,11 +48,11 @@ fn map_unique(ctx: &Context, args: Vec<RedisString>) -> RedisResult {
     let res = match values {
         None => RedisValue::Null,
         Some(values) => {
-            let mut set: HashSet<RedisValueKey> = HashSet::new();
+            let mut set: BTreeSet<RedisValueKey> = BTreeSet::new();
             for (_, value) in values.into_iter() {
                 set.insert(RedisValueKey::BulkRedisString(value));
             }
-            RedisValue::Set(set)
+            RedisValue::OrderedSet(set)
         }
     };
 

src/context/mod.rs

@@ -466,6 +466,17 @@ impl Context {
                 raw::Status::Ok
             }
 
+            Ok(RedisValue::OrderedMap(map)) => {
+                raw::reply_with_map(self.ctx, map.len() as c_long);
+
+                for (key, value) in map {
+                    self.reply_with_key(key);
+                    self.reply(Ok(value));
+                }
+
+                raw::Status::Ok
+            }
+
             Ok(RedisValue::Set(set)) => {
                 raw::reply_with_set(self.ctx, set.len() as c_long);
                 set.into_iter().for_each(|e| {
@@ -475,6 +486,15 @@ impl Context {
                 raw::Status::Ok
             }
 
+            Ok(RedisValue::OrderedSet(set)) => {
+                raw::reply_with_set(self.ctx, set.len() as c_long);
+                set.into_iter().for_each(|e| {
+                    self.reply_with_key(e);
+                });
+
+                raw::Status::Ok
+            }
+
             Ok(RedisValue::Null) => raw::reply_with_null(self.ctx),
 
             Ok(RedisValue::NoReply) => raw::Status::Ok,

src/redisvalue.rs

@@ -3,11 +3,11 @@ use crate::{
     CallReply, RedisError, RedisString,
 };
 use std::{
-    collections::{HashMap, HashSet},
+    collections::{BTreeMap, BTreeSet, HashMap, HashSet},
     hash::Hash,
 };
 
-#[derive(Debug, PartialEq, Eq, Hash, Clone)]
+#[derive(Debug, PartialEq, Eq, Hash, Clone, PartialOrd, Ord)]
 pub enum RedisValueKey {
     Integer(i64),
     String(String),
@@ -32,6 +32,8 @@ pub enum RedisValue {
     StaticError(&'static str),
     Map(HashMap<RedisValueKey, RedisValue>),
     Set(HashSet<RedisValueKey>),
+    OrderedMap(BTreeMap<RedisValueKey, RedisValue>),
+    OrderedSet(BTreeSet<RedisValueKey>),
     Null,
     NoReply, // No reply at all (as opposed to a Null reply)
 }