Add try/into map iterator for message ref (#9)

Author: vlopes11

msgpacker/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "msgpacker"
-version = "0.3.0"
+version = "0.3.1"
 authors = ["Victor Lopez <victor@codx.io>"]
 categories = ["compression", "encoding", "parser-implementations"]
 edition = "2021"

msgpacker/src/map/map_ref.rs

@@ -24,6 +24,10 @@ impl<'a> MapEntryRef<'a> {
         &self.val
     }
 
+    pub(crate) fn into_inner(self) -> (MessageRef<'a>, MessageRef<'a>) {
+        (self.key, self.val)
+    }
+
     /// Access the internal key and value as a tuple of references
     pub const fn inner(&self) -> (&MessageRef<'a>, &MessageRef<'a>) {
         (&self.key, &self.val)

msgpacker/src/message_ref.rs

@@ -102,6 +102,27 @@ impl<'a> MessageRef<'a> {
     as_value_ref!(as_map, &'a [MapEntryRef], Map);
     as_value_ref!(as_extension, &'a ExtensionRef, Extension);
 
+    /// Attempt to match every item of the message as map, and then convert it to key/value pairs
+    pub fn try_collect_map<M, K, V>(self) -> Option<io::Result<M>>
+    where
+        M: FromIterator<(K, V)>,
+        K: TryFrom<MessageRef<'a>, Error = io::Error>,
+        V: TryFrom<MessageRef<'a>, Error = io::Error>,
+    {
+        let m = match self {
+            MessageRef::Map(m) => m,
+            _ => return None,
+        };
+
+        let map = m
+            .into_iter()
+            .map(|entry| entry.into_inner())
+            .map(|(key, value)| K::try_from(key).and_then(|k| V::try_from(value).map(|v| (k, v))))
+            .collect();
+
+        Some(map)
+    }
+
     /// Return `true` if the message is nil
     pub const fn is_nil(&self) -> bool {
         matches!(self, Self::Nil)
@@ -882,3 +903,16 @@ impl<'a> SizeableMessage for MessageRef<'a> {
         }
     }
 }
+
+impl<'a, K, V> FromIterator<(K, V)> for MessageRef<'a>
+where
+    K: Into<MessageRef<'a>>,
+    V: Into<MessageRef<'a>>,
+{
+    fn from_iter<T: IntoIterator<Item = (K, V)>>(iter: T) -> Self {
+        iter.into_iter()
+            .map(|(key, value)| MapEntryRef::new(key.into(), value.into()))
+            .collect::<Vec<_>>()
+            .into()
+    }
+}

msgpacker/tests/pack_unpack.rs

@@ -1,5 +1,6 @@
 use msgpacker::prelude::*;
 
+use std::collections::HashMap;
 use std::io::{self, Cursor, Seek};
 use std::time::Duration;
 
@@ -139,3 +140,22 @@ fn pack_unpack() -> io::Result<()> {
 
     Ok(())
 }
+
+#[test]
+fn pack_unpack_map_works() {
+    let data = vec![
+        (10u32, String::from("test 1")),
+        (38u32, String::from("")),
+        (187u32, String::from("another test")),
+    ];
+
+    let map = data.clone().into_iter().collect::<HashMap<_, _>>();
+    let msg = MessageRef::from_iter(map.iter().map(|(k, v)| (*k, v)));
+
+    let map_p = msg
+        .try_collect_map()
+        .expect("message is not a map")
+        .expect("failed to parse items");
+
+    assert_eq!(map, map_p);
+}