refactor(core)!: change Assets::iter item to use Cow (#10907)

* refactor(core): change `Assets::iter` item to use `Cow`

make the iterator more flexible to support Assets implementations that do not rely on static assets

* fix test?

* lint

* lint

* clippy again

Author: lucasfernog

.changes/assets-iter-cow.md

@@ -0,0 +1,6 @@
+---
+"tauri-utils": patch:breaking
+"tauri": patch:breaking
+---
+
+The `Assets::iter` function now must return a iterator with `Item = (Cow<'_, str>, Cow<'_, [u8]>)` to be more flexible on contexts where the assets are not `'static`.

crates/tauri-utils/src/assets.rs

@@ -12,6 +12,9 @@ use std::{
   path::{Component, Path},
 };
 
+/// Assets iterator.
+pub type AssetsIter<'a> = dyn Iterator<Item = (Cow<'a, str>, Cow<'a, [u8]>)> + 'a;
+
 /// Represent an asset file path in a normalized way.
 ///
 /// The following rules are enforced and added if needed:
@@ -155,8 +158,13 @@ impl EmbeddedAssets {
   }
 
   /// Iterate on the assets.
-  pub fn iter(&self) -> Box<dyn Iterator<Item = (&str, &[u8])> + '_> {
-    Box::new(self.assets.into_iter().map(|(k, b)| (*k, *b)))
+  pub fn iter(&self) -> Box<AssetsIter<'_>> {
+    Box::new(
+      self
+        .assets
+        .into_iter()
+        .map(|(k, b)| (Cow::Borrowed(*k), Cow::Borrowed(*b))),
+    )
   }
 
   /// CSP hashes for the given asset.

crates/tauri/src/app.rs

@@ -37,7 +37,7 @@ use tauri_runtime::{
   window::DragDropEvent,
   RuntimeInitArgs,
 };
-use tauri_utils::PackageInfo;
+use tauri_utils::{assets::AssetsIter, PackageInfo};
 
 use serde::Serialize;
 use std::{
@@ -309,7 +309,7 @@ impl<R: Runtime> AssetResolver<R> {
   }
 
   /// Iterate on all assets.
-  pub fn iter(&self) -> Box<dyn Iterator<Item = (&str, &[u8])> + '_> {
+  pub fn iter(&self) -> Box<AssetsIter<'_>> {
     self.manager.assets.iter()
   }
 }

crates/tauri/src/ipc/protocol.rs

@@ -17,7 +17,6 @@ use http::{
   },
   HeaderValue, Method, Request, StatusCode,
 };
-use mime::APPLICATION_OCTET_STREAM;
 use url::Url;
 
 use super::{CallbackFn, InvokeResponse};
@@ -279,7 +278,8 @@ fn handle_ipc_message<R: Runtime>(request: Request<String>, manager: &AppManager
           serde_json::from_str::<IsolationMessage<'_>>(request.body())
             .map_err(Into::into)
             .and_then(|message| {
-              let is_raw = message.payload.content_type() == &APPLICATION_OCTET_STREAM.to_string();
+              let is_raw =
+                message.payload.content_type() == &mime::APPLICATION_OCTET_STREAM.to_string();
               let payload = crypto_keys.decrypt(message.payload)?;
               Ok(Message {
                 cmd: message.cmd,

crates/tauri/src/lib.rs

@@ -79,6 +79,7 @@ pub use tauri_macros::include_image;
 pub use tauri_macros::mobile_entry_point;
 pub use tauri_macros::{command, generate_handler};
 
+use tauri_utils::assets::AssetsIter;
 pub use url::Url;
 
 pub(crate) mod app;
@@ -351,7 +352,7 @@ pub trait Assets<R: Runtime>: Send + Sync + 'static {
   fn get(&self, key: &AssetKey) -> Option<Cow<'_, [u8]>>;
 
   /// Iterator for the assets.
-  fn iter(&self) -> Box<dyn Iterator<Item = (&str, &[u8])> + '_>;
+  fn iter(&self) -> Box<tauri_utils::assets::AssetsIter<'_>>;
 
   /// Gets the hashes for the CSP tag of the HTML on the given path.
   fn csp_hashes(&self, html_path: &AssetKey) -> Box<dyn Iterator<Item = CspHash<'_>> + '_>;
@@ -362,7 +363,7 @@ impl<R: Runtime> Assets<R> for EmbeddedAssets {
     EmbeddedAssets::get(self, key)
   }
 
-  fn iter(&self) -> Box<dyn Iterator<Item = (&str, &[u8])> + '_> {
+  fn iter(&self) -> Box<AssetsIter<'_>> {
     EmbeddedAssets::iter(self)
   }
 
@@ -1084,7 +1085,7 @@ mod test_utils {
     fn check_spawn_task(task in "[a-z]+") {
       // create dummy task function
       let dummy_task = async move {
-        format!("{task}-run-dummy-task");
+        let _ = format!("{task}-run-dummy-task");
       };
       // call spawn
       crate::async_runtime::spawn(dummy_task);

crates/tauri/src/test/mod.rs

@@ -64,7 +64,7 @@ use crate::{
 };
 use tauri_utils::{
   acl::resolved::Resolved,
-  assets::{AssetKey, CspHash},
+  assets::{AssetKey, AssetsIter, CspHash},
   config::{AppConfig, Config},
 };
 
@@ -82,8 +82,13 @@ impl<R: Runtime> Assets<R> for NoopAsset {
     None
   }
 
-  fn iter(&self) -> Box<dyn Iterator<Item = (&str, &[u8])> + '_> {
-    Box::new(self.assets.iter().map(|(k, b)| (k.as_str(), b.as_slice())))
+  fn iter(&self) -> Box<AssetsIter<'_>> {
+    Box::new(
+      self
+        .assets
+        .iter()
+        .map(|(k, b)| (Cow::Borrowed(k.as_str()), Cow::Borrowed(b.as_slice()))),
+    )
   }
 
   fn csp_hashes(&self, html_path: &AssetKey) -> Box<dyn Iterator<Item = CspHash<'_>> + '_> {