From 10968423e81e1987f7e7ed4baede5b14452307b9 Mon Sep 17 00:00:00 2001
From: pjht <pterpstra@pterpstra.com>
Date: Mon, 30 Sep 2024 13:31:51 -0500
Subject: [PATCH] Add seek function

---
 src/lib.rs | 47 ++++++++++++++++++++++++++++++++---------------
 1 file changed, 32 insertions(+), 15 deletions(-)

diff --git a/src/lib.rs b/src/lib.rs
index 72aa322..d4e3078 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,17 +1,21 @@
 use std::{
-    borrow::Cow,
-    boxed::Box,
-    os::mikros::ipc::{
+    borrow::Cow, boxed::Box, os::mikros::ipc::{
         self,
         rpc::{self, CallId, IncomingCall},
-    },
-    vec::Vec,
+    }, vec::Vec
 };
 
 use bitflags::bitflags;
 use parking_lot::RwLock;
 use serde::{Deserialize, Serialize};
 
+#[derive(Deserialize, Serialize)]
+pub enum SeekFrom {
+    Start(u64),
+    End(i64),
+    Current(i64),
+}
+
 bitflags! {
     #[derive(Serialize, Deserialize, Clone, Copy, Debug)]
     pub struct PollEvents: u16 {
@@ -33,8 +37,8 @@ static SERVER: RwLock<Option<Box<dyn Server>>> = RwLock::new(None);
 const PROTO: u16 = 1;
 
 pub trait Server: Send + Sync {
-    fn read<'a>(&'a self, fd: u64, pos: u64, len: usize) -> Result<Cow<'a, [u8]>, ()>;
-    fn write(&self, fd: u64, pos: u64, data: &[u8]) -> Result<(), ()>;
+    fn read<'a>(&'a self, fd: u64, len: usize) -> Result<Cow<'a, [u8]>, ()>;
+    fn write(&self, fd: u64, data: &[u8]) -> Result<(), ()>;
     fn close(&self, fd: u64);
     fn size(&self, fd: u64) -> Option<u64>;
     fn dup(&self, fd: u64) -> Option<u64>;
@@ -45,6 +49,7 @@ pub trait Server: Send + Sync {
         None
     }
     fn cancel_poll(&self, _poll_id: u64) {}
+    fn seek(&self, fd: u64, pos: SeekFrom) -> u64;
 }
 
 #[derive(Copy, Clone)]
@@ -114,26 +119,26 @@ impl Client {
         Self(pid)
     }
 
-    pub fn read(self, fd: u64, pos: u64, len: usize) -> Result<Vec<u8>, ()> {
+    pub fn read(self, fd: u64, len: usize) -> Result<Vec<u8>, ()> {
         postcard::from_bytes(
             &rpc::send_call(
                 self.0,
                 PROTO,
                 0,
-                &postcard::to_stdvec(&(fd, pos, len)).unwrap(),
+                &postcard::to_stdvec(&(fd, len)).unwrap(),
             )
             .get_return(),
         )
         .unwrap()
     }
 
-    pub fn write(self, fd: u64, pos: u64, data: &[u8]) -> Result<(), ()> {
+    pub fn write(self, fd: u64, data: &[u8]) -> Result<(), ()> {
         postcard::from_bytes(
             &rpc::send_call(
                 self.0,
                 PROTO,
                 1,
-                &postcard::to_stdvec(&(fd, pos, data)).unwrap(),
+                &postcard::to_stdvec(&(fd, data)).unwrap(),
             )
             .get_return(),
         )
@@ -179,6 +184,13 @@ impl Client {
             call_id,
         }
     }
+
+    pub fn seek(&self, fd: u64, pos: SeekFrom) -> u64 {
+        postcard::from_bytes(
+            &rpc::send_call(self.0, PROTO, 8, &postcard::to_stdvec(&(fd, pos)).unwrap()).get_return(),
+        )
+        .unwrap()
+    }
 }
 
 pub fn register_server(server: Box<dyn Server>) {
@@ -196,16 +208,16 @@ fn callback(call: IncomingCall) {
     let server = server_lock.as_ref().unwrap();
     match call.func {
         0 => {
-            let (fd, pos, len) = postcard::from_bytes(call.args()).unwrap();
-            let ret = server.read(fd, pos, len);
+            let (fd, len) = postcard::from_bytes(call.args()).unwrap();
+            let ret = server.read(fd, len);
             let ser_size = postcard::experimental::serialized_size(&ret).unwrap();
             let mut buf = call.make_return_buf(ser_size);
             postcard::to_slice(&ret, &mut buf[..]).unwrap();
             buf.send();
         }
         1 => {
-            let (fd, pos, data): (u64, u64, Vec<u8>) = postcard::from_bytes(call.args()).unwrap();
-            let ret = postcard::to_stdvec(&server.write(fd, pos, &data)).unwrap();
+            let (fd, data): (u64, Vec<u8>) = postcard::from_bytes(call.args()).unwrap();
+            let ret = postcard::to_stdvec(&server.write(fd, &data)).unwrap();
             call.send_return(&ret);
         }
         2 => {
@@ -240,6 +252,11 @@ fn callback(call: IncomingCall) {
             let ret = postcard::to_stdvec(&server.cancel_poll(poll_id)).unwrap();
             call.send_return(&ret);
         }
+        8 => {
+            let (fd, pos) = postcard::from_bytes(call.args()).unwrap();
+            let ret = postcard::to_stdvec(&server.seek(fd, pos)).unwrap();
+            call.send_return(&ret);
+        }
         _ => (),
     }
 }