optimization: reduce heap allocation (#970)

* optimization: reduce heap allocation

Prefer str::from_utf8 over String::from_utf8 to avoid
unnecesary heap allocation

* fmt

* chore: add unclog

---------

Co-authored-by: Farhad Shabani <[email protected]>

Author: blasrodri

.changelog/unreleased/improvements/970-reduce-heap-allocation.md

@@ -0,0 +1,3 @@
+- Reduce heap allocation by using `str` instead of `String` places we convert
+  domain event attributes to the ABCI event attributes
+  ([\#970](https://github.com/cosmos/ibc-rs/issues/970))

ibc-core/ics02-client/types/src/events.rs

@@ -153,7 +153,7 @@ impl From<HeaderAttribute> for abci::EventAttribute {
     fn from(attr: HeaderAttribute) -> Self {
         (
             HEADER_ATTRIBUTE_KEY,
-            String::from_utf8(hex::encode(attr.header))
+            str::from_utf8(&hex::encode(attr.header))
                 .expect("Never fails because hexadecimal is valid UTF-8"),
         )
             .into()

ibc-core/ics04-channel/types/src/events/packet_attributes.rs

@@ -59,7 +59,7 @@ impl TryFrom<PacketDataAttribute> for Vec<abci::EventAttribute> {
                 .into(),
             (
                 PKT_DATA_HEX_ATTRIBUTE_KEY,
-                String::from_utf8(hex::encode(attr.packet_data))
+                str::from_utf8(&hex::encode(attr.packet_data))
                     .expect("Never fails because hexadecimal is valid UTF8"),
             )
                 .into(),
@@ -329,7 +329,7 @@ impl TryFrom<AcknowledgementAttribute> for Vec<abci::EventAttribute> {
                 .into(),
             (
                 PKT_ACK_HEX_ATTRIBUTE_KEY,
-                String::from_utf8(hex::encode(attr.acknowledgement))
+                str::from_utf8(&hex::encode(attr.acknowledgement))
                     .expect("Never fails because hexadecimal is always valid UTF-8"),
             )
                 .into(),

ibc-primitives/src/prelude.rs

@@ -4,5 +4,5 @@ pub use alloc::borrow::ToOwned;
 pub use alloc::boxed::Box;
 pub use alloc::string::{String, ToString};
 pub use alloc::vec::Vec;
-pub use alloc::{format, vec};
+pub use alloc::{format, str, vec};
 pub use core::prelude::v1::*;