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@ -61,6 +61,35 @@ public static Future<Void, RuntimeException> regular_function() {
}
```
### Why not annotations?
Unfortunately annotations cannot be put on lambdas.
## Use this library
```kotlin
// settings.gradle.kts
sourceControl {
gitRepository(URI.create("https://github.com/ParkerTenBroeck/generators.git")) {
producesModule("com.parkertenbroeck.generators:lib")
}
}
// build.gradle.kts
implementation("com.parkertenbroeck.generators:lib:0.1.0")
```
This library requires the application be ran with a custom class loader, there is a utility provided to make this easier.
```java
public static void main(String[] args) {
// loads the current class with a custom class loader and calls *this* method with the provided arguments.
// *this* method - the one used to call `runWithStateMachines`
RT.runWithStateMachines(StateMachineClassLoader.Config.builtin(), (Object) args);
// past this point generators will be created on methods which match the criteria
}
```
## Oddities
```java
@ -130,7 +159,7 @@ public static Future<Void, RuntimeException> add_reorder() {
### synchronized
when a generator/future method is declared as `synchronized` the `next`/`poll`/`cancel` functions will all be synchronized over the instance or class which the method was declared in.
when a generator/future method is declared as `synchronized` the `next`/`poll`/`cancel` functions will all be synchronized over the instance or class the method was declared in.
it is important to note that the monitor is **NOT** held across suspend points where the function returns.
@ -146,22 +175,7 @@ static Future<Void, RuntimeException> unsync(Object value) {
## How this works
This library requires the application be ran with a custom class loader as follows (this can be done manually if needed)
```java
public static void main(String[] args) {
// loads the current class with a custom class loader and calls *this* method with the provided arguments.
// *this* method - the one used to call `runWithStateMachines`
RT.runWithStateMachines(StateMachineClassLoader.Config.builtin(), (Object) args);
// past this point generators will be created on methods which match the criteria
}
```
Once finished any class loaded will be scanned for methods which match a particular signature.
When matched a shim is introduced into the source method and a class is constructed which stores all state for the future/generator
A basic example here where we have some parameters
Say we have some async function like this.
```java
public static Future<Void, IOException> example(@Cancellation("close") Socket socket, String message) throws IOException {
try(socket){
@ -170,6 +184,8 @@ public static Future<Void, IOException> example(@Cancellation("close") Socket so
return Future.ret();
}
```
The loader will see the methods which it needs to transform, then modify the bytecode, transforming the function into a class where state across suspend points is saved/restored (local variables & the current state of the stack).
This is a (modified) decompiled version of the generated method.
```java
public static Future<Void, IOException> example(Socket socket, String message) {
@ -273,10 +289,3 @@ public static Future<Void, IOException> example(Socket socket, String message) {
};
}
```
### Steps
- A functions signature and code is determined to be "of interest"
- When a function is found we wish to modify it first builds a frame(locals, stack, annotations) for every area of interest in the function
- The number of unique locations which can be suspended from are kept track of
- A switch is built which handles each state the function can resume from setting up any locals/stack that needs to be resumed as well as setting up the code for saving locals/stack state
- the locations which special methods are found are modified to perform their particular function and potentially save state and return
- (Futures) generate cancellation code for locals which have specified so, and cancellation for a pending future.