feat: deserializable events, fixes #147

macros/src/standard/nep297.rs

@@ -153,11 +153,11 @@ pub fn expand(meta: Nep297Meta) -> Result<TokenStream, darling::Error> {
  impl #imp #me::standard::nep297::ToEventLog for #ident #ty #wher {
  type Data = #ident #ty;
 
- fn to_event_log<'__el>(&'__el self) -> #me::standard::nep297::EventLog<&'__el Self> {
+ fn to_event_log<'__el>(&'__el self) -> #me::standard::nep297::EventLog<&'__el Self::Data> {
  #me::standard::nep297::EventLog {
- standard: #standard,
- version: #version,
- event: #event,
+ standard: #standard.into(),
+ version: #version.into(),
+ event: #event.into(),
  data: self,
  }
  }

src/owner.rs

@@ -49,7 +49,7 @@ const NO_PROPOSED_OWNER_FAIL_MESSAGE: &str = "No proposed owner";
  crate = "crate",
  macros = "near_sdk_contract_tools_macros"
 )]
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub enum OwnerEvent {
  /// Emitted when the current owner of the contract changes
  Transfer {

src/pause.rs

@@ -36,7 +36,7 @@ const PAUSED_FAIL_MESSAGE: &str = "Disallowed while contract is paused";
  crate = "crate",
  macros = "near_sdk_contract_tools_macros"
 )]
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub enum PauseEvent {
  /// Emitted when the contract is paused
  Pause,

src/standard/nep141/event.rs

@@ -17,7 +17,7 @@ use near_sdk_contract_tools_macros::event;
  standard = "nep141",
  version = "1.0.0"
 )]
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub enum Nep141Event<'a> {
  /// Token mint event. Emitted when tokens are created and total_supply is
  /// increased.

src/standard/nep171/event.rs

@@ -15,7 +15,7 @@ use near_sdk_contract_tools_macros::event;
  standard = "nep171",
  version = "1.2.0"
 )]
-#[derive(Debug, Clone)]
+#[derive(Debug)]
 pub enum Nep171Event<'a> {
  /// Emitted when a token is newly minted.
  NftMint(Vec<NftMintLog<'a>>),

src/standard/nep297.rs

@@ -1,13 +1,16 @@
 //! Helpers for `#[derive(near_sdk_contract_tools::Nep297)]`
 
-use near_sdk::{serde::Serialize, serde_json};
+use std::borrow::Cow;
+
+use near_sdk::{
+ serde::{self, Deserialize, Serialize},
+ serde_json,
+};
 
 /// Emit events according to the [NEP-297 event standard](https://nomicon.io/Standards/EventsFormat).
 ///
 /// # Examples
 ///
-/// ## Normal events
-///
 /// ```
 /// use near_sdk_contract_tools::event;
 ///
@@ -27,10 +30,10 @@ use near_sdk::{serde::Serialize, serde_json};
 /// e.emit();
 /// ```
 pub trait Event {
- /// Converts the event into an NEP-297 event-formatted string
+ /// Converts the event into an NEP-297 event-formatted string.
  fn to_event_string(&self) -> String;
 
- /// Emits the event string to the blockchain
+ /// Emits the event string to the blockchain.
  fn emit(&self);
 }
 
@@ -60,26 +63,92 @@ where
  }
 }
 
-/// This type can be converted into an [`EventLog`] struct
+/// This type can be converted into an [`EventLog`] struct.
 pub trait ToEventLog {
- /// Metadata associated with the event
- type Data: ?Sized;
+ /// Metadata associated with the event.
+ type Data;
 
- /// Retrieves the event log before serialization
+ /// Retrieves the event log before serialization.
  fn to_event_log(&self) -> EventLog<&Self::Data>;
 }
 
 /// NEP-297 Event Log Data
 /// <https://github.com/near/NEPs/blob/master/neps/nep-0297.md#specification>
-#[derive(Serialize, Clone, Debug)]
+#[derive(Serialize, Deserialize, Clone, Debug, PartialEq, Eq)]
 #[serde(crate = "near_sdk::serde")]
-pub struct EventLog<T> {
- /// Name of the event standard, e.g. "nep171"
- pub standard: &'static str,
- /// Version of the standard, e.g. "1.0.0"
- pub version: &'static str,
- /// Name of the particular event, e.g. "nft_mint", "ft_transfer"
- pub event: &'static str,
- /// Data type of the event metadata
+pub struct EventLog<'a, T> {
+ /// Name of the event standard, e.g. `"nep171"`.
+ pub standard: Cow<'a, str>,
+ /// Version of the standard, e.g. `"1.0.0"`.
+ pub version: Cow<'a, str>,
+ /// Name of the particular event, e.g. `"nft_mint"`, `"ft_transfer"`.
+ pub event: Cow<'a, str>,
+ /// Data type of the event metadata.
  pub data: T,
 }
+
+impl<'de, T: Deserialize<'de>> EventLog<'de, T> {
+ /// Deserializes an event log from a string.
+ ///
+ /// # Errors
+ ///
+ /// Will return `Err` if the string is not a valid event log. A valid event
+ /// log begins with the string `"EVENT_JSON:"`, and is followed by a JSON
+ /// string.
+ pub fn from_event_log_string(s: &'de str) -> Result<Self, serde::de::value::Error> {
+ let data_str = s
+ .strip_prefix("EVENT_JSON:")
+ .ok_or(serde::de::Error::custom(serde::de::Unexpected::Str(
+ "EVENT_JSON:",
+ )))?;
+ let data =
+ serde_json::from_str::<EventLog<T>>(data_str).map_err(serde::de::Error::custom)?;
+ let x = Some(1);
+ x.as_ref();
+ Ok(data)
+ }
+
+ /// Converts the event log into a borrowed reference.
+ pub fn as_ref(&self) -> EventLog<&T> {
+ EventLog {
+ standard: Cow::Borrowed(&self.standard),
+ version: Cow::Borrowed(&self.version),
+ event: Cow::Borrowed(&self.event),
+ data: &self.data,
+ }
+ }
+}
+
+#[cfg(test)]
+mod tests {
+ use super::*;
+
+ #[test]
+ fn to_and_from_event_log() {
+ #[derive(Debug, PartialEq, Eq)]
+ struct MyEvent;
+
+ impl ToEventLog for MyEvent {
+ type Data = u32;
+
+ fn to_event_log(&self) -> EventLog<&u32> {
+ EventLog {
+ standard: "nep171".into(),
+ version: "1.0.0".into(),
+ event: "nft_mint".into(),
+ data: &1,
+ }
+ }
+ }
+
+ let event = MyEvent;
+
+ let string = event.to_event_string();
+
+ assert_eq!(string, "EVENT_JSON:{\"standard\":\"nep171\",\"version\":\"1.0.0\",\"event\":\"nft_mint\",\"data\":1}");
+
+ let from_event_log_str = EventLog::<u32>::from_event_log_string(&string).unwrap();
+
+ assert_eq!(from_event_log_str.as_ref(), event.to_event_log());
+ }
+}