Implement fileinputstream::read and test

Author: dlunch

java_runtime/src/classes/java/io/file_input_stream.rs

@@ -22,6 +22,7 @@ impl FileInputStream {
             methods: vec![
                 JavaMethodProto::new("<init>", "(Ljava/io/File;)V", Self::init, Default::default()),
                 JavaMethodProto::new("read", "([B)I", Self::read, Default::default()),
+                JavaMethodProto::new("read", "()I", Self::read_byte, Default::default()),
                 JavaMethodProto::new("close", "()V", Self::close, Default::default()),
             ],
             fields: vec![JavaFieldProto::new("fd", "Ljava/io/FileDescriptor;", Default::default())],
@@ -68,6 +69,21 @@ impl FileInputStream {
         Ok(read as _)
     }
 
+    async fn read_byte(jvm: &Jvm, _: &mut RuntimeContext, this: ClassInstanceRef<Self>) -> Result<i32> {
+        tracing::debug!("java.io.FileInputStream::read({:?})", &this);
+
+        let fd = jvm.get_field(&this, "fd", "Ljava/io/FileDescriptor;").await?;
+        let mut rust_file = FileDescriptor::file(jvm, fd).await?;
+
+        let mut buf = [0; 1];
+        let read = rust_file.read(&mut buf).await.unwrap();
+        if read == 0 {
+            return Ok(-1);
+        }
+
+        Ok(buf[0] as i32)
+    }
+
     async fn close(_jvm: &Jvm, _: &mut RuntimeContext, this: ClassInstanceRef<Self>) -> Result<()> {
         tracing::debug!("stub java.io.FileInputStream::close({:?})", &this);
 

java_runtime/tests/classes/java/io/file_input_stream.rs

@@ -0,0 +1,45 @@
+use alloc::vec;
+
+use jvm::{Result, runtime::JavaLangString};
+
+use test_utils::test_jvm_filesystem;
+
+#[tokio::test]
+async fn test_file_input_stream_read_buf() -> Result<()> {
+    let filesystem = [("test.txt".into(), b"hello world".to_vec())];
+    let jvm = test_jvm_filesystem(filesystem.into_iter().collect()).await?;
+
+    let file = JavaLangString::from_rust_string(&jvm, "test.txt").await?;
+
+    let java_file = jvm.new_class("java/io/File", "(Ljava/lang/String;)V", (file,)).await?;
+    let fis = jvm.new_class("java/io/FileInputStream", "(Ljava/io/File;)V", (java_file,)).await?;
+
+    let bytes = jvm.instantiate_array("B", 11).await?;
+    let read: i32 = jvm.invoke_virtual(&fis, "read", "([B)I", (bytes.clone(),)).await?;
+
+    let length = jvm.array_length(&bytes).await?;
+    let mut buf = vec![0; length];
+    jvm.array_raw_buffer(&bytes).await?.read(0, &mut buf)?;
+
+    assert_eq!(read, 11);
+    assert_eq!(buf, vec![104, 101, 108, 108, 111, 32, 119, 111, 114, 108, 100]);
+
+    Ok(())
+}
+
+#[tokio::test]
+async fn test_file_input_stream_read_int() -> Result<()> {
+    let filesystem = [("test.txt".into(), b"hello world".to_vec())];
+    let jvm = test_jvm_filesystem(filesystem.into_iter().collect()).await?;
+
+    let file = JavaLangString::from_rust_string(&jvm, "test.txt").await?;
+
+    let java_file = jvm.new_class("java/io/File", "(Ljava/lang/String;)V", (file,)).await?;
+    let fis = jvm.new_class("java/io/FileInputStream", "(Ljava/io/File;)V", (java_file,)).await?;
+
+    let read: i32 = jvm.invoke_virtual(&fis, "read", "()I", ()).await?;
+
+    assert_eq!(read, 104);
+
+    Ok(())
+}

java_runtime/tests/classes/java/io/mod.rs

@@ -2,6 +2,7 @@ mod buffered_reader;
 mod byte_array_output_stream;
 mod data_input_stream;
 mod data_output_stream;
+mod file_input_stream;
 mod input_stream_reader;
 mod print_writer;
 mod random_access_file;