add TimeStamp type to facilitate deserialization (#88)

Author: saghm

src/bson.rs

@@ -595,6 +595,27 @@ impl Bson {
     }
 }
 
+/// `TimeStamp` representation in struct for serde serialization
+///
+/// Just a helper for convenience
+///
+/// ```rust,ignore
+/// #[macro_use]
+/// extern crate serde_derive;
+/// extern crate bson;
+/// use bson::TimeStamp;
+///
+/// #[derive(Serialize, Deserialize)]
+/// struct Foo {
+///     timestamp: TimeStamp,
+/// }
+/// ```
+#[derive(Debug, Eq, PartialEq, Clone)]
+pub struct TimeStamp {
+    pub t: u32,
+    pub i: u32,
+}
+
 /// `DateTime` representation in struct for serde serialization
 ///
 /// Just a helper for convenience

src/decoder/serde.rs

@@ -5,7 +5,7 @@ use serde::de::{self, Deserialize, Deserializer, Visitor, MapAccess, SeqAccess,
                 DeserializeSeed, EnumAccess};
 use serde::de::{Error, Unexpected};
 
-use bson::{Bson, UtcDateTime};
+use bson::{Bson, TimeStamp, UtcDateTime};
 use oid::ObjectId;
 use ordered::{OrderedDocument, OrderedDocumentIntoIterator, OrderedDocumentVisitor};
 use super::error::{DecoderError, DecoderResult};
@@ -601,6 +601,26 @@ impl<'de> Deserializer<'de> for MapDecoder {
     }
 }
 
+impl<'de> Deserialize<'de> for TimeStamp {
+    fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
+        where D: Deserializer<'de>
+    {
+        use serde::de::Error;
+
+        match Bson::deserialize(deserializer)? {
+            Bson::TimeStamp(ts) => {
+                let ts = ts.to_be();
+
+                Ok(TimeStamp {
+                    t: ((ts as u64) >> 32) as u32,
+                    i: (ts & 0xFFFF_FFFF) as u32,
+                })
+            }
+            _ => Err(D::Error::custom("expecting UtcDateTime")),
+        }
+    }
+}
+
 impl<'de> Deserialize<'de> for UtcDateTime {
     fn deserialize<D>(deserializer: D) -> Result<Self, D::Error>
         where D: Deserializer<'de>
@@ -613,3 +633,4 @@ impl<'de> Deserialize<'de> for UtcDateTime {
         }
     }
 }
+

src/lib.rs

@@ -55,7 +55,7 @@ extern crate linked_hash_map;
 extern crate hostname;
 extern crate hex;
 
-pub use self::bson::{Bson, Document, Array, UtcDateTime};
+pub use self::bson::{Bson, Document, Array, TimeStamp, UtcDateTime};
 pub use self::encoder::{encode_document, to_bson, Encoder, EncoderResult, EncoderError};
 pub use self::decoder::{decode_document, decode_document_utf8_lossy, from_bson, Decoder, DecoderResult, DecoderError};
 pub use self::ordered::{ValueAccessError, ValueAccessResult};

tests/serde.rs

@@ -58,6 +58,22 @@ fn test_de_map() {
     assert_eq!(expected, map);
 }
 
+#[test]
+fn test_de_timestamp() {
+    use bson::TimeStamp;
+
+    #[derive(Deserialize, Eq, PartialEq, Debug)]
+    struct Foo {
+        ts: TimeStamp,
+    }
+
+    let foo: Foo = bson::from_bson(Bson::Document(doc! {
+        "ts": Bson::TimeStamp(0x0A00_0000_0C00_0000),
+    })).unwrap();
+
+    assert_eq!(foo.ts, TimeStamp { t: 12, i: 10 });
+}
+
 #[test]
 fn test_ser_datetime() {
     use chrono::{Utc, Timelike};