ch1-3 完成 Channel 基础代码，还需要调整注释。

code/Cargo.toml

@@ -2,4 +2,5 @@
 members = [
     "ch01-01",
     "ch01-02",
+    "ch01-03",
 ]

code/ch01-03/.gitignore

@@ -0,0 +1,2 @@
+target
+Cargo.lock

code/ch01-03/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "ch01-03"
+version = "0.1.0"
+authors = ["Runji Wang <wangrunji0408@163.com>"]
+edition = "2018"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
+spin = "0.7"
+downcast-rs = { version = "1.2.0", default-features = false }
+bitflags = "1.2"
+buddy_system_allocator = "0.7"

code/ch01-03/src/error.rs

@@ -0,0 +1,232 @@
+// ANCHOR: result
+///
+pub type ZxResult<T = ()> = Result<T, ZxError>;
+// ANCHOR_END: result
+
+// ANCHOR: error_begin
+/// Zircon statuses are signed 32 bit integers. The space of values is
+/// divided as follows:
+/// - The zero value is for the OK status.
+/// - Negative values are defined by the system, in this file.
+/// - Positive values are reserved for protocol-specific error values,
+///   and will never be defined by the system.
+#[allow(non_camel_case_types, dead_code)]
+#[repr(i32)]
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub enum ZxError {
+    OK = 0,
+
+    // ======= Internal failures =======
+    /// The system encountered an otherwise unspecified error
+    /// while performing the operation.
+    INTERNAL = -1,
+
+    /// The operation is not implemented, supported,
+    /// or enabled.
+    NOT_SUPPORTED = -2,
+    // ANCHOR_END: error_begin
+    /// The system was not able to allocate some resource
+    /// needed for the operation.
+    NO_RESOURCES = -3,
+
+    /// The system was not able to allocate memory needed
+    /// for the operation.
+    NO_MEMORY = -4,
+
+    // -5 used to be ZX_ERR_CALL_FAILED.
+    /// The system call was interrupted, but should be
+    /// retried.  This should not be seen outside of the VDSO.
+    INTERNAL_INTR_RETRY = -6,
+
+    // ======= Parameter errors =======
+    /// an argument is invalid, ex. null pointer
+    INVALID_ARGS = -10,
+
+    /// A specified handle value does not refer to a handle.
+    BAD_HANDLE = -11,
+
+    /// The subject of the operation is the wrong type to
+    /// perform the operation.
+    /// Example: Attempting a message_read on a thread handle.
+    WRONG_TYPE = -12,
+
+    /// The specified syscall number is invalid.
+    BAD_SYSCALL = -13,
+
+    /// An argument is outside the valid range for this
+    /// operation.
+    OUT_OF_RANGE = -14,
+
+    /// A caller provided buffer is too small for
+    /// this operation.
+    BUFFER_TOO_SMALL = -15,
+
+    // ======= Precondition or state errors =======
+    /// operation failed because the current state of the
+    /// object does not allow it, or a precondition of the operation is
+    /// not satisfied
+    BAD_STATE = -20,
+
+    /// The time limit for the operation elapsed before
+    /// the operation completed.
+    TIMED_OUT = -21,
+
+    /// The operation cannot be performed currently but
+    /// potentially could succeed if the caller waits for a prerequisite
+    /// to be satisfied, for example waiting for a handle to be readable
+    /// or writable.
+    /// Example: Attempting to read from a channel that has no
+    /// messages waiting but has an open remote will return ZX_ERR_SHOULD_WAIT.
+    /// Attempting to read from a channel that has no messages waiting
+    /// and has a closed remote end will return ZX_ERR_PEER_CLOSED.
+    SHOULD_WAIT = -22,
+
+    /// The in-progress operation (e.g. a wait) has been
+    /// canceled.
+    CANCELED = -23,
+
+    /// The operation failed because the remote end of the
+    /// subject of the operation was closed.
+    PEER_CLOSED = -24,
+
+    /// The requested entity is not found.
+    NOT_FOUND = -25,
+
+    /// An object with the specified identifier
+    /// already exists.
+    /// Example: Attempting to create a file when a file already exists
+    /// with that name.
+    ALREADY_EXISTS = -26,
+
+    /// The operation failed because the named entity
+    /// is already owned or controlled by another entity. The operation
+    /// could succeed later if the current owner releases the entity.
+    ALREADY_BOUND = -27,
+
+    /// The subject of the operation is currently unable
+    /// to perform the operation.
+    /// Note: This is used when there's no direct way for the caller to
+    /// observe when the subject will be able to perform the operation
+    /// and should thus retry.
+    UNAVAILABLE = -28,
+
+    // ======= Permission check errors =======
+    /// The caller did not have permission to perform
+    /// the specified operation.
+    ACCESS_DENIED = -30,
+
+    // ======= Input-output errors =======
+    /// Otherwise unspecified error occurred during I/O.
+    IO = -40,
+
+    /// The entity the I/O operation is being performed on
+    /// rejected the operation.
+    /// Example: an I2C device NAK'ing a transaction or a disk controller
+    /// rejecting an invalid command, or a stalled USB endpoint.
+    IO_REFUSED = -41,
+
+    /// The data in the operation failed an integrity
+    /// check and is possibly corrupted.
+    /// Example: CRC or Parity error.
+    IO_DATA_INTEGRITY = -42,
+
+    /// The data in the operation is currently unavailable
+    /// and may be permanently lost.
+    /// Example: A disk block is irrecoverably damaged.
+    IO_DATA_LOSS = -43,
+
+    /// The device is no longer available (has been
+    /// unplugged from the system, powered down, or the driver has been
+    /// unloaded,
+    IO_NOT_PRESENT = -44,
+
+    /// More data was received from the device than expected.
+    /// Example: a USB "babble" error due to a device sending more data than
+    /// the host queued to receive.
+    IO_OVERRUN = -45,
+
+    /// An operation did not complete within the required timeframe.
+    /// Example: A USB isochronous transfer that failed to complete due to an overrun or underrun.
+    IO_MISSED_DEADLINE = -46,
+
+    /// The data in the operation is invalid parameter or is out of range.
+    /// Example: A USB transfer that failed to complete with TRB Error
+    IO_INVALID = -47,
+
+    // ======== Filesystem Errors ========
+    /// Path name is too long.
+    BAD_PATH = -50,
+
+    /// Object is not a directory or does not support
+    /// directory operations.
+    /// Example: Attempted to open a file as a directory or
+    /// attempted to do directory operations on a file.
+    NOT_DIR = -51,
+
+    /// Object is not a regular file.
+    NOT_FILE = -52,
+
+    /// This operation would cause a file to exceed a
+    /// filesystem-specific size limit
+    FILE_BIG = -53,
+
+    /// Filesystem or device space is exhausted.
+    NO_SPACE = -54,
+
+    /// Directory is not empty.
+    NOT_EMPTY = -55,
+
+    // ======== Flow Control ========
+    // These are not errors, as such, and will never be returned
+    // by a syscall or public API.  They exist to allow callbacks
+    // to request changes in operation.
+    /// Do not call again.
+    /// Example: A notification callback will be called on every
+    /// event until it returns something other than ZX_OK.
+    /// This status allows differentiation between "stop due to
+    /// an error" and "stop because the work is done."
+    STOP = -60,
+
+    /// Advance to the next item.
+    /// Example: A notification callback will use this response
+    /// to indicate it did not "consume" an item passed to it,
+    /// but by choice, not due to an error condition.
+    NEXT = -61,
+
+    /// Ownership of the item has moved to an asynchronous worker.
+    ///
+    /// Unlike ZX_ERR_STOP, which implies that iteration on an object
+    /// should stop, and ZX_ERR_NEXT, which implies that iteration
+    /// should continue to the next item, ZX_ERR_ASYNC implies
+    /// that an asynchronous worker is responsible for continuing iteration.
+    ///
+    /// Example: A notification callback will be called on every
+    /// event, but one event needs to handle some work asynchronously
+    /// before it can continue. ZX_ERR_ASYNC implies the worker is
+    /// responsible for resuming iteration once its work has completed.
+    ASYNC = -62,
+
+    // ======== Network-related errors ========
+    /// Specified protocol is not
+    /// supported.
+    PROTOCOL_NOT_SUPPORTED = -70,
+
+    /// Host is unreachable.
+    ADDRESS_UNREACHABLE = -71,
+
+    /// Address is being used by someone else.
+    ADDRESS_IN_USE = -72,
+
+    /// Socket is not connected.
+    NOT_CONNECTED = -73,
+
+    /// Remote peer rejected the connection.
+    CONNECTION_REFUSED = -74,
+
+    /// Connection was reset.
+    CONNECTION_RESET = -75,
+    // ANCHOR: error_end
+    /// Connection was aborted.
+    CONNECTION_ABORTED = -76,
+}
+// ANCHOR_END: error_end

code/ch01-03/src/ipc/channel.rs

@@ -0,0 +1,180 @@
+use {
+    super::*,
+    crate::error::*,
+    crate::object::*,
+    alloc::collections::VecDeque,
+    alloc::sync::{Arc, Weak},
+    alloc::vec::Vec,
+    core::convert::TryInto,
+    core::sync::atomic::{AtomicU32, Ordering},
+    spin::Mutex,
+};
+
+pub struct Channel {
+    base: KObjectBase,
+    peer: Weak<Channel>,
+    recv_queue: Mutex<VecDeque<T>>,
+    next_txid: AtomicU32,
+}
+
+type T = MessagePacket;
+type TxID = u32;
+
+impl_kobject!(Channel
+    fn peer(&self) -> ZxResult<Arc<dyn KernelObject>> {
+        let peer = self.peer.upgrade().ok_or(ZxError::PEER_CLOSED)?;
+        Ok(peer)
+    }
+    fn related_koid(&self) -> KoID {
+        self.peer.upgrade().map(|p| p.id()).unwrap_or(0)
+    }
+);
+
+impl Channel {
+    /// Create a channel and return a pair of its endpoints
+    #[allow(unsafe_code)]
+    pub fn create() -> (Arc<Self>, Arc<Self>) {
+        let mut channel0 = Arc::new(Channel {
+            base: KObjectBase::default(),
+            peer: Weak::default(),
+            recv_queue: Default::default(),
+            next_txid: AtomicU32::new(0x8000_0000),
+        });
+        let channel1 = Arc::new(Channel {
+            base: KObjectBase::default(),
+            peer: Arc::downgrade(&channel0),
+            recv_queue: Default::default(),
+            next_txid: AtomicU32::new(0x8000_0000),
+        });
+        // no other reference of `channel0`
+        unsafe {
+            Arc::get_mut_unchecked(&mut channel0).peer = Arc::downgrade(&channel1);
+        }
+        (channel0, channel1)
+    }
+
+    /// Read a packet from the channel if check is ok, otherwise the msg will keep.
+    pub fn read(&self) -> ZxResult<T> {
+        let mut recv_queue = self.recv_queue.lock();
+        if let Some(msg) = recv_queue.front() {
+            let msg = recv_queue.pop_front().unwrap();
+            return Ok(msg);
+        }
+        if self.peer_closed() {
+            Err(ZxError::PEER_CLOSED)
+        } else {
+            Err(ZxError::SHOULD_WAIT)
+        }
+    }
+
+    /// Write a packet to the channel
+    pub fn write(&self, msg: T) -> ZxResult {
+        let peer = self.peer.upgrade().ok_or(ZxError::PEER_CLOSED)?;
+        peer.push_general(msg);
+        Ok(())
+    }
+
+    /// Push a message to general queue, called from peer.
+    fn push_general(&self, msg: T) {
+        let mut send_queue = self.recv_queue.lock();
+        send_queue.push_back(msg);
+    }
+
+    /// Generate a new transaction ID for `call`.
+    fn new_txid(&self) -> TxID {
+        self.next_txid.fetch_add(1, Ordering::SeqCst)
+    }
+
+    /// Is peer channel closed?
+    fn peer_closed(&self) -> bool {
+        self.peer.strong_count() == 0
+    }
+}
+
+/// The message transferred in the channel.
+/// See [Channel](struct.Channel.html) for details.
+#[derive(Default)]
+pub struct MessagePacket {
+    /// The transition id of the message packet
+    pub txid: TxID,
+    /// The data carried by the message packet
+    pub data: Vec<u8>,
+    /// See [Channel](struct.Channel.html) for details.
+    pub handles: Vec<Handle>,
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use alloc::boxed::Box;
+    use core::sync::atomic::*;
+    use core::time::Duration;
+
+    #[test]
+    fn test_basics() {
+        let (end0, end1) = Channel::create();
+        assert!(Arc::ptr_eq(
+            &end0.peer().unwrap().downcast_arc().unwrap(),
+            &end1
+        ));
+        assert_eq!(end0.related_koid(), end1.id());
+
+        drop(end1);
+        assert_eq!(end0.peer().unwrap_err(), ZxError::PEER_CLOSED);
+        assert_eq!(end0.related_koid(), 0);
+    }
+
+    #[test]
+    fn read_write() {
+        let (channel0, channel1) = Channel::create();
+        // write a message to each other
+        let txid0 = channel0.new_txid();
+        channel0
+            .write(MessagePacket {
+                txid: txid0,
+                data: Vec::from("hello 1"),
+                handles: Vec::new(),
+            })
+            .unwrap();
+        let txid1 = channel1.new_txid();
+        channel1
+            .write(MessagePacket {
+                txid: txid1,
+                data: Vec::from("hello 0"),
+                handles: Vec::new(),
+            })
+            .unwrap();
+
+        // read message should success
+        let recv_msg = channel1.read().unwrap();
+        assert_eq!(recv_msg.txid, txid0);
+        assert_eq!(recv_msg.data.as_slice(), b"hello 1");
+        assert!(recv_msg.handles.is_empty());
+
+        let recv_msg = channel0.read().unwrap();
+        assert_eq!(recv_msg.txid, txid1);
+        assert_eq!(recv_msg.data.as_slice(), b"hello 0");
+        assert!(recv_msg.handles.is_empty());
+
+        // read more message should fail.
+        assert_eq!(channel0.read().err(), Some(ZxError::SHOULD_WAIT));
+        assert_eq!(channel1.read().err(), Some(ZxError::SHOULD_WAIT));
+    }
+
+    #[test]
+    fn peer_closed() {
+        let (channel0, channel1) = Channel::create();
+        // write a message from peer, then drop it
+        channel1.write(MessagePacket::default()).unwrap();
+        drop(channel1);
+        // read the first message should success.
+        channel0.read().unwrap();
+        // read more message should fail.
+        assert_eq!(channel0.read().err(), Some(ZxError::PEER_CLOSED));
+        // write message should fail.
+        assert_eq!(
+            channel0.write(MessagePacket::default()),
+            Err(ZxError::PEER_CLOSED)
+        );
+    }
+}

code/ch01-03/src/ipc/mod.rs

@@ -0,0 +1,4 @@
+use super::*;
+
+mod channel;
+pub use self::channel::*;

code/ch01-03/src/lib.rs

@@ -0,0 +1,9 @@
+#![no_std]
+#![feature(get_mut_unchecked)]
+
+extern crate alloc;
+
+mod error;
+mod ipc;
+mod object;
+mod task;

code/ch01-03/src/object/handle.rs

@@ -0,0 +1,18 @@
+// ANCHOR: handle
+use super::{KernelObject, Rights};
+use alloc::sync::Arc;
+
+/// 内核对象句柄
+#[derive(Clone)]
+pub struct Handle {
+    pub object: Arc<dyn KernelObject>,
+    pub rights: Rights,
+}
+
+impl Handle {
+    /// 创建一个新句柄
+    pub fn new(object: Arc<dyn KernelObject>, rights: Rights) -> Self {
+        Handle { object, rights }
+    }
+}
+// ANCHOR_END: handle

code/ch01-03/src/object/mod.rs

@@ -0,0 +1,160 @@
+use crate::error::*;
+use alloc::string::String;
+use alloc::sync::Arc;
+use core::fmt::Debug;
+use core::sync::atomic::*;
+use downcast_rs::{impl_downcast, DowncastSync};
+use spin::Mutex;
+
+// ANCHOR: mod
+mod handle;
+mod rights;
+
+pub use self::handle::*;
+pub use self::rights::*;
+// ANCHOR_END: mod
+
+/// 内核对象公共接口
+pub trait KernelObject: DowncastSync + Debug {
+    /// 获取对象 ID
+    fn id(&self) -> KoID;
+    /// 获取对象类型名
+    fn type_name(&self) -> &str;
+    /// 获取对象名称
+    fn name(&self) -> String;
+    /// 设置对象名称
+    fn set_name(&self, name: &str);
+    /// 尝试获取对象伙伴
+    ///
+    /// 当前该对象必须是 `Channel`
+    fn peer(&self) -> ZxResult<Arc<dyn KernelObject>> {
+        Err(ZxError::NOT_SUPPORTED)
+    }
+    /// 尝试获取关联对象 id，否则返回 0
+    ///
+    /// 当前该对象必须是 `Channel`
+    fn related_koid(&self) -> KoID {
+        0
+    }
+}
+
+impl_downcast!(sync KernelObject);
+
+/// 对象 ID 类型
+pub type KoID = u64;
+
+/// 内核对象核心结构
+pub struct KObjectBase {
+    /// 对象 ID
+    pub id: KoID,
+    inner: Mutex<KObjectBaseInner>,
+}
+
+/// `KObjectBase` 的内部可变部分
+#[derive(Default)]
+struct KObjectBaseInner {
+    name: String,
+}
+
+impl Default for KObjectBase {
+    /// 创建一个新 `KObjectBase`
+    fn default() -> Self {
+        KObjectBase {
+            id: Self::new_koid(),
+            inner: Default::default(),
+        }
+    }
+}
+
+impl KObjectBase {
+    /// 生成一个唯一的 ID
+    fn new_koid() -> KoID {
+        static NEXT_KOID: AtomicU64 = AtomicU64::new(1024);
+        NEXT_KOID.fetch_add(1, Ordering::SeqCst)
+    }
+    /// 获取对象名称
+    pub fn name(&self) -> String {
+        self.inner.lock().name.clone()
+    }
+    /// 设置对象名称
+    pub fn set_name(&self, name: &str) {
+        self.inner.lock().name = String::from(name);
+    }
+}
+
+/// 为内核对象 struct 自动实现 `KernelObject` trait 的宏。
+#[macro_export] // 导出宏，可在 crate 外部使用
+macro_rules! impl_kobject {
+    // 匹配类型名，并可以提供函数覆盖默认实现
+    ($class:ident $( $fn:tt )*) => {
+        // 为对象实现 KernelObject trait，方法直接转发到内部 struct
+        impl KernelObject for $class {
+            fn id(&self) -> KoID {
+                // 直接访问内部的 pub 属性
+                self.base.id
+            }
+            fn type_name(&self) -> &str {
+                // 用 stringify! 宏将输入转成字符串
+                stringify!($class)
+            }
+            // 注意宏里面的类型要写完整路径，例如：alloc::string::String
+            fn name(&self) -> alloc::string::String {
+                self.base.name()
+            }
+            fn set_name(&self, name: &str){
+                // 直接访问内部的 pub 方法
+                self.base.set_name(name)
+            }
+            // 可以传入任意数量的函数，覆盖 trait 的默认实现
+            $( $fn )*
+        }
+        // 为对象实现 Debug trait
+        impl core::fmt::Debug for $class {
+            fn fmt(
+                &self,
+                f: &mut core::fmt::Formatter<'_>,
+            ) -> core::result::Result<(), core::fmt::Error> {
+                // 输出对象类型、ID 和名称
+                f.debug_tuple(&stringify!($class))
+                    .field(&self.id())
+                    .field(&self.name())
+                    .finish()
+            }
+        }
+    };
+}
+
+/// 空对象
+pub struct DummyObject {
+    // 其中必须包含一个名为 `base` 的 `KObjectBase`
+    base: KObjectBase,
+}
+
+// 使用刚才的宏，声明其为内核对象，自动生成必要的代码
+impl_kobject!(DummyObject);
+
+impl DummyObject {
+    /// 创建一个新 `DummyObject`
+    pub fn new() -> Arc<Self> {
+        Arc::new(DummyObject {
+            base: KObjectBase::default(),
+        })
+    }
+}
+
+#[cfg(test)]
+#[test]
+fn impl_kobject() {
+    use alloc::format;
+    let dummy = DummyObject::new();
+    let object: Arc<dyn KernelObject> = dummy;
+    assert_eq!(object.type_name(), "DummyObject");
+    assert_eq!(object.name(), "");
+    object.set_name("dummy");
+    assert_eq!(object.name(), "dummy");
+    assert_eq!(
+        format!("{:?}", object),
+        format!("DummyObject({}, \"dummy\")", object.id())
+    );
+    let _result: Arc<DummyObject> = object.downcast_arc::<DummyObject>().unwrap();
+}

code/ch01-03/src/object/rights.rs

@@ -0,0 +1,35 @@
+// ANCHOR: rights
+use bitflags::bitflags;
+
+bitflags! {
+    /// 句柄权限
+    pub struct Rights: u32 {
+        const DUPLICATE = 1 << 0;
+        const TRANSFER = 1 << 1;
+        const READ = 1 << 2;
+        const WRITE = 1 << 3;
+        const EXECUTE = 1 << 4;
+        const MAP = 1 << 5;
+        const GET_PROPERTY = 1 << 6;
+        const SET_PROPERTY = 1 << 7;
+        const ENUMERATE = 1 << 8;
+        const DESTROY = 1 << 9;
+        const SET_POLICY = 1 << 10;
+        const GET_POLICY = 1 << 11;
+        const SIGNAL = 1 << 12;
+        const SIGNAL_PEER = 1 << 13;
+        const WAIT = 1 << 14;
+        const INSPECT = 1 << 15;
+        const MANAGE_JOB = 1 << 16;
+        const MANAGE_PROCESS = 1 << 17;
+        const MANAGE_THREAD = 1 << 18;
+        const APPLY_PROFILE = 1 << 19;
+        const SAME_RIGHTS = 1 << 31;
+
+        const BASIC = Self::TRANSFER.bits | Self::DUPLICATE.bits | Self::WAIT.bits | Self::INSPECT.bits;
+        const IO = Self::READ.bits | Self::WRITE.bits;
+
+        const DEFAULT_CHANNEL = Self::BASIC.bits & !Self::DUPLICATE.bits | Self::IO.bits | Self::SIGNAL.bits | Self::SIGNAL_PEER.bits;
+    }
+}
+// ANCHOR_END: rights

code/ch01-03/src/task/mod.rs

@@ -0,0 +1,3 @@
+use super::*;
+
+mod process;

code/ch01-03/src/task/process.rs

@@ -0,0 +1,77 @@
+use super::*;
+use crate::error::*;
+use crate::object::*;
+use alloc::collections::BTreeMap;
+use alloc::sync::Arc;
+use spin::Mutex;
+
+// ANCHOR: process
+/// 进程对象
+pub struct Process {
+    base: KObjectBase,
+    inner: Mutex<ProcessInner>,
+}
+
+impl_kobject!(Process);
+
+struct ProcessInner {
+    handles: BTreeMap<HandleValue, Handle>,
+}
+
+pub type HandleValue = u32;
+
+impl Process {
+    /// 创建一个新的进程对象
+    pub fn new() -> Arc<Self> {
+        Arc::new(Process {
+            base: KObjectBase::default(),
+            inner: Mutex::new(ProcessInner {
+                handles: BTreeMap::default(),
+            }),
+        })
+    }
+    // ANCHOR_END: process
+
+    // ANCHOR: add_remove_handle
+    /// 添加一个新的对象句柄
+    pub fn add_handle(&self, handle: Handle) -> HandleValue {
+        let mut inner = self.inner.lock();
+        let value = (0 as HandleValue..)
+            .find(|idx| !inner.handles.contains_key(idx))
+            .unwrap();
+        inner.handles.insert(value, handle);
+        value
+    }
+
+    /// 删除一个对象句柄
+    pub fn remove_handle(&self, handle_value: HandleValue) {
+        self.inner.lock().handles.remove(&handle_value);
+    }
+    // ANCHOR_END: add_remove_handle
+
+    // ANCHOR: get_object_with_rights
+    /// 根据句柄值查找内核对象，并检查权限
+    pub fn get_object_with_rights<T: KernelObject>(
+        &self,
+        handle_value: HandleValue,
+        desired_rights: Rights,
+    ) -> ZxResult<Arc<T>> {
+        let handle = self
+            .inner
+            .lock()
+            .handles
+            .get(&handle_value)
+            .ok_or(ZxError::BAD_HANDLE)?
+            .clone();
+        // check type before rights
+        let object = handle
+            .object
+            .downcast_arc::<T>()
+            .map_err(|_| ZxError::WRONG_TYPE)?;
+        if !handle.rights.contains(desired_rights) {
+            return Err(ZxError::ACCESS_DENIED);
+        }
+        Ok(object)
+    }
+    // ANCHOR_END: get_object_with_rights
+}