Use new LazyLock to store message channels

documentation/docs/frequently-asked-questions.md

@@ -233,10 +233,10 @@ onPressed: () async {
 ```
 
 ```rust title="native/hub/src/sample_functions.rs"
-pub async fn respond() -> Result<()> {
+pub async fn respond() {
     use messages::tutorial_resource::*;
 
-    let receiver = MyUniqueInput::get_dart_signal_receiver()?;
+    let receiver = MyUniqueInput::get_dart_signal_receiver();
     while let Some(dart_signal) = receiver.recv().await {
         let my_unique_input = dart_signal.message;
         MyUniqueOutput {
@@ -245,8 +245,6 @@ pub async fn respond() -> Result<()> {
         }
         .send_signal_to_dart();
     }
-
-    Ok(())
 }
 ```
 

documentation/docs/messaging.md

@@ -68,7 +68,7 @@ MyDataInput( ... ).sendSignalToRust();
 ```
 
 ```rust title="Rust"
-let receiver = MyDataInput::get_dart_signal_receiver()?;
+let receiver = MyDataInput::get_dart_signal_receiver();
 while let Some(dart_signal) = receiver.recv().await {
     let message: MyDataInput = dart_signal.message;
     // Custom Rust logic here
@@ -88,7 +88,7 @@ MyDataInput( ... ).sendSignalToRust(binary);
 ```
 
 ```rust title="Rust"
-let receiver = MyDataInput::get_dart_signal_receiver()?;
+let receiver = MyDataInput::get_dart_signal_receiver();
 while let Some(dart_signal) = receiver.recv().await {
     let message: MyDataInput = dart_signal.message;
     let binary: Vec<u8> = dart_signal.binary;

documentation/docs/tutorial.md

@@ -62,10 +62,10 @@ use crate::common::*;
 use crate::messages;
 use rinf::debug_print;
 
-pub async fn calculate_precious_data() -> Result<()> {
+pub async fn calculate_precious_data() {
     use messages::tutorial_messages::*;
 
-    let receiver = MyPreciousData::get_dart_signal_receiver()?; // GENERATED
+    let receiver = MyPreciousData::get_dart_signal_receiver(); // GENERATED
     while let Some(dart_signal) = receiver.recv().await {
         let my_precious_data = dart_signal.message;
 
@@ -79,8 +79,6 @@ pub async fn calculate_precious_data() -> Result<()> {
         debug_print!("{new_numbers:?}");
         debug_print!("{new_string}");
     }
-
-    Ok(())
 }
 ```
 
@@ -217,18 +215,16 @@ children: [
 use crate::common::*;
 use crate::messages;
 
-pub async fn tell_treasure() -> Result<()> {
+pub async fn tell_treasure() {
     use messages::tutorial_messages::*;
 
     let mut current_value: i32 = 1;
 
-    let receiver = MyTreasureInput::get_dart_signal_receiver()?; // GENERATED
+    let receiver = MyTreasureInput::get_dart_signal_receiver(); // GENERATED
     while let Some(_) = receiver.recv().await {
         MyTreasureOutput { current_value }.send_signal_to_dart(); // GENERATED
         current_value += 1;
     }
-
-    Ok(())
 }
 ```
 

flutter_package/bin/src/message.dart

@@ -272,7 +272,7 @@ use rinf::{
     DartSignal, MessageReceiver, MessageSender,
     RinfError,
 };
-use std::sync::Mutex;
+use std::sync::LazyLock;
 
 ''',
           atFront: true,
@@ -289,38 +289,16 @@ use std::sync::Mutex;
           await insertTextToFile(
             rustPath,
             '''
-type ${messageName}Cell = Mutex<Option<(
+type ${messageName}Cell = LazyLock<(
     MessageSender<DartSignal<${normalizePascal(messageName)}>>,
-    Option<MessageReceiver<DartSignal<${normalizePascal(messageName)}>>>,
-)>>;
+    MessageReceiver<DartSignal<${normalizePascal(messageName)}>>,
+)>;
 pub static ${snakeName.toUpperCase()}_CHANNEL: ${messageName}Cell =
-    Mutex::new(None);
+    LazyLock::new(message_channel);
 
 impl ${normalizePascal(messageName)} {
-    pub fn get_dart_signal_receiver()
-        -> Result<MessageReceiver<DartSignal<Self>>, RinfError> 
-    {       
-        let mut guard = ${snakeName.toUpperCase()}_CHANNEL
-            .lock()
-            .map_err(|_| RinfError::LockMessageChannel)?;
-        if guard.is_none() {
-            let (sender, receiver) = message_channel();
-            guard.replace((sender, Some(receiver)));
-        }
-        let (mut sender, mut receiver_option) = guard
-            .take()
-            .ok_or(RinfError::NoMessageChannel)?;
-        // After Dart's hot restart or app reopen on mobile devices,
-        // a sender from the previous run already exists
-        // which is now closed.
-        if sender.is_closed() {
-            let receiver;
-            (sender, receiver) = message_channel();
-            receiver_option = Some(receiver);
-        }
-        let receiver = receiver_option.ok_or(RinfError::MessageReceiverTaken)?;
-        guard.replace((sender, None));
-        Ok(receiver)
+    pub fn get_dart_signal_receiver() -> MessageReceiver<DartSignal<Self>> {
+        ${snakeName.toUpperCase()}_CHANNEL.1.clone()
     }
 }
 ''',
@@ -467,28 +445,7 @@ new_hash_map.insert(
             message,
             binary: binary.to_vec(),
         };
-        let mut guard = ${snakeName.toUpperCase()}_CHANNEL
-            .lock()
-            .map_err(|_| RinfError::LockMessageChannel)?;
-        if guard.is_none() {
-            let (sender, receiver) = message_channel();
-            guard.replace((sender, Some(receiver)));
-        }
-        let mut pair = guard
-            .as_ref()
-            .ok_or(RinfError::NoMessageChannel)?;
-        // After Dart's hot restart or app reopen on mobile devices,
-        // a sender from the previous run already exists
-        // which is now closed.
-        if pair.0.is_closed() {
-            let (sender, receiver) = message_channel();
-            guard.replace((sender, Some(receiver)));
-            pair = guard
-                .as_ref()
-                .ok_or(RinfError::NoMessageChannel)?;
-        }
-        let sender = &pair.0;
-        let _ = sender.send(dart_signal);
+        ${snakeName.toUpperCase()}_CHANNEL.0.send(dart_signal);
         Ok(())
     }),
 );

flutter_package/example/native/hub/src/sample_functions.rs

@@ -13,13 +13,13 @@ static IS_DEBUG_MODE: bool = true;
 static IS_DEBUG_MODE: bool = false;
 
 // Business logic for the counter widget.
-pub async fn tell_numbers() -> Result<()> {
+pub async fn tell_numbers() {
     use messages::counter_number::*;
 
     let mut vector = Vec::new();
 
     // Stream getter is generated from a marked Protobuf message.
-    let receiver = SampleNumberInput::get_dart_signal_receiver()?;
+    let receiver = SampleNumberInput::get_dart_signal_receiver();
     while let Some(dart_signal) = receiver.recv().await {
         // Extract values from the message received from Dart.
         // This message is a type that's declared in its Protobuf file.
@@ -40,8 +40,6 @@ pub async fn tell_numbers() -> Result<()> {
         }
         .send_signal_to_dart();
     }
-
-    Ok(())
 }
 
 // Business logic for the fractal image.
@@ -104,15 +102,14 @@ pub async fn stream_fractal() {
 
 // A dummy function that uses sample messages to eliminate warnings.
 #[allow(dead_code)]
-async fn use_messages() -> Result<()> {
+async fn use_messages() {
     use messages::sample_folder::sample_file::*;
-    let _ = SampleInput::get_dart_signal_receiver()?;
+    let _ = SampleInput::get_dart_signal_receiver();
     SampleOutput {
         kind: 3,
         oneof_input: Some(sample_output::OneofInput::Age(25)),
     }
     .send_signal_to_dart();
-    Ok(())
 }
 
 // Business logic for testing various crates.

flutter_package/template/native/hub/src/lib.rs

@@ -28,18 +28,16 @@ async fn main() -> Result<()> {
     Ok(())
 }
 
-async fn communicate() -> Result<()> {
+async fn communicate() {
     use messages::basic::*;
 
     // Send signals to Dart like below.
     SmallNumber { number: 7 }.send_signal_to_dart();
 
     // Get receivers that listen to Dart signals like below.
-    let receiver = SmallText::get_dart_signal_receiver()?;
+    let receiver = SmallText::get_dart_signal_receiver();
     while let Some(dart_signal) = receiver.recv().await {
         let message: SmallText = dart_signal.message;
         rinf::debug_print!("{message:?}");
     }
-
-    Ok(())
 }