Add FileDescriptorId type and update Runtime trait to use fd abstraction

Author: dlunch

java_runtime/src/lib.rs

@@ -7,7 +7,7 @@ mod runtime;
 
 pub use self::{
     loader::{get_bootstrap_class_loader, get_runtime_class_proto},
-    runtime::{File, FileSize, FileStat, FileType, IOError, IOResult, Runtime, SpawnCallback},
+    runtime::{File, FileDescriptorId, FileSize, FileStat, FileType, IOError, IOResult, Runtime, SpawnCallback},
 };
 
 pub type RuntimeContext = dyn runtime::Runtime;

java_runtime/src/runtime.rs

@@ -7,7 +7,7 @@ use dyn_clone::{DynClone, clone_trait_object};
 
 use jvm::{ClassDefinition, Jvm, Result as JvmResult};
 
-pub use io::{File, FileSize, FileStat, FileType, IOError, IOResult};
+pub use io::{File, FileDescriptorId, FileSize, FileStat, FileType, IOError, IOResult};
 
 #[async_trait::async_trait]
 pub trait SpawnCallback: Sync + Send {
@@ -23,11 +23,13 @@ pub trait Runtime: Sync + Send + DynClone {
     fn now(&self) -> u64; // unix time in millis
     fn current_task_id(&self) -> u64;
 
-    fn stdin(&self) -> IOResult<Box<dyn File>>;
-    fn stdout(&self) -> IOResult<Box<dyn File>>;
-    fn stderr(&self) -> IOResult<Box<dyn File>>;
+    fn stdin(&self) -> IOResult<FileDescriptorId>;
+    fn stdout(&self) -> IOResult<FileDescriptorId>;
+    fn stderr(&self) -> IOResult<FileDescriptorId>;
 
-    async fn open(&self, path: &str, write: bool) -> IOResult<Box<dyn File>>;
+    async fn open(&self, path: &str, write: bool) -> IOResult<FileDescriptorId>;
+    fn get_file(&self, fd: FileDescriptorId) -> IOResult<Box<dyn File>>;
+    fn close_file(&self, fd: FileDescriptorId);
     async fn unlink(&self, path: &str) -> IOResult<()>;
     async fn metadata(&self, path: &str) -> IOResult<FileStat>;
 

java_runtime/src/runtime/io.rs

@@ -2,6 +2,19 @@ use alloc::boxed::Box;
 
 use dyn_clone::{DynClone, clone_trait_object};
 
+#[derive(Debug, Clone, Copy, PartialEq, Eq, PartialOrd, Ord)]
+pub struct FileDescriptorId(u32);
+
+impl FileDescriptorId {
+    pub fn new(id: u32) -> Self {
+        Self(id)
+    }
+
+    pub fn id(&self) -> u32 {
+        self.0
+    }
+}
+
 #[derive(Debug)]
 pub enum IOError {
     Unsupported,