Grcov report - server.rs

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// SPDX-License-Identifier: BSD-2-Clause

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/*

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 * session/server.rs - Types relating to client-side CoAP sessions.

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 * This file is part of the libcoap-rs crate, see the README and LICENSE files for

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 * more information and terms of use.

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 * Copyright © 2021-2023 The NAMIB Project Developers, all rights reserved.

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 * See the README as well as the LICENSE file for more information.

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*/

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use std::cell::{Ref, RefMut};

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use libcoap_sys::{

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    coap_session_get_app_data, coap_session_get_type, coap_session_reference, coap_session_release,

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    coap_session_set_app_data, coap_session_t, coap_session_type_t,

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};

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use super::{CoapSessionCommon, CoapSessionInner, CoapSessionInnerProvider};

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use crate::mem::{CoapFfiRcCell, DropInnerExclusively};

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impl DropInnerExclusively for CoapServerSession<'_> {

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    fn drop_exclusively(self) {

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        let sess_ref = self.inner.clone();

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        std::mem::drop(self);

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        sess_ref.drop_exclusively();

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/// Representation of a server-side CoAP session.

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#[derive(Debug, Clone)]

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pub struct CoapServerSession<'a> {

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    /// Inner part of this server-side session

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    /// A weak version of this reference is stored inside of the user/app data pointer in the

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    /// raw session struct so that it can be passed through the FFI barrier.

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    inner: CoapFfiRcCell<CoapServerSessionInner<'a>>,

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    ref_counted: bool,

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#[derive(Debug)]

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/// Inner part of a server-side CoAP session.

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struct CoapServerSessionInner<'a> {

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    inner: CoapSessionInner<'a>,

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impl CoapServerSession<'_> {

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    /// Creates a CoapServerSession from a raw session.

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///

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    /// This function will increment the libcoap-internal reference counter for the session by one.

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    /// Dropping the CoapServerSession will then decrement it again.

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///

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    /// # Panics

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    /// Panics if the given pointer is a null pointer or the raw session is not a server-side

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    /// session.

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///

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    /// # Safety

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    /// The provided pointer must be valid for the entire (here arbitrarily chosen) lifetime of the

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    /// CoapServerSession<'a>, most notably the program will abort if the [CoapContext] is dropped

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    /// before this session is.

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    /// The existing value in the `app_data` field of the raw session will be overridden.

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    /// Make sure that this is actually okay to do so — most importantly, no other [CoapSession] may

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    /// already be stored there.

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///

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    /// If you wish to restore an existing [CoapSession] from its raw counterpart, use

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    /// [from_raw()](CoapServerSession::from_raw) instead.

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    pub(crate) unsafe fn initialize_raw<'a>(raw_session: *mut coap_session_t) -> CoapServerSession<'a> {

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        assert!(!raw_session.is_null(), "provided raw session was null");

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        let raw_session_type = coap_session_get_type(raw_session);

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        let inner = CoapSessionInner::new(raw_session);

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        let session_inner = match raw_session_type {

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            coap_session_type_t::COAP_SESSION_TYPE_NONE => panic!("provided session has no type"),

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            coap_session_type_t::COAP_SESSION_TYPE_CLIENT => {

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                panic!("attempted to create server session from raw client session")

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},

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            coap_session_type_t::COAP_SESSION_TYPE_SERVER => CoapServerSessionInner { inner },

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            coap_session_type_t::COAP_SESSION_TYPE_HELLO => CoapServerSessionInner { inner },

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            _ => unreachable!("unknown session type"),

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};

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        let session_ref = CoapFfiRcCell::new(session_inner);

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        coap_session_set_app_data(raw_session, session_ref.create_raw_weak());

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        // Increase libcoap-internal reference counter for raw session so that it doesn't get freed

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        // as long as this CoapServerSession instance exists.

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        coap_session_reference(raw_session);

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        CoapServerSession {

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            inner: session_ref,

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            ref_counted: true,

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    /// Restores a [CoapServerSession] from its raw counterpart.

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///

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    /// Make sure that this struct cannot outlive the [CoapContext] its session originates from, as

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    /// the lifetime cannot be inferred by the compiler and dropping the context will panic/abort if

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    /// the inner session is still referenced anywhere else.

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///

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    /// This function will increment the libcoap-internal reference counter for the session by one.

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    /// Dropping the CoapServerSession will then decrement it again.

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///

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    /// # Panics

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    /// Panics if the provided raw session pointer or its app_data field is null or the raw session

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    /// is not a server-side session.

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///

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    /// # Safety

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    /// The provided pointer must be valid for the entire lifetime of this struct.

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    /// The provided session's app data must be a valid argument to

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    /// [`CoapFfiRcCell<CoapServerSessionInner>::clone_raw_rc`](CoapFfiRcCell::clone_raw_rc).

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    pub(crate) unsafe fn from_raw<'a>(raw_session: *mut coap_session_t) -> CoapServerSession<'a> {

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        let mut session = Self::from_raw_without_refcount(raw_session);

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        coap_session_reference(raw_session);

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        session.ref_counted = true;

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        session

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    /// Restores a [CoapServerSession] from its raw counterpart without increasing its reference

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    /// counter (useful if acquiring libcoap's global lock is undesired).

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///

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    /// Make sure that this struct cannot outlive the [CoapContext] its session originates from, as

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    /// the lifetime cannot be inferred by the compiler and dropping the context will panic/abort if

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    /// the inner session is still referenced anywhere else.

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///

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    /// In addition to the above, you must also ensure that the session will not be cleaned up by

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    /// libcoap in the meantime, as the reference counter is not increased while constructing the

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    /// instance.

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///

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    /// This function will increment the libcoap-internal reference counter for the session by one.

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    /// Dropping the CoapServerSession will then decrement it again.

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///

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    /// # Panics

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///

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    /// Panics if the provided raw session pointer or its app_data field is null or the raw session

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    /// is not a server-side session.

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///

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    /// # Safety

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    /// The provided pointer must be valid for the entire lifetime of this struct.

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///

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    /// This also implies that libcoap *must not* clean up this session during the lifetime of this

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    /// struct, which could happen at any time if the libcoap context is not locked.

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///

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    /// The provided session's app data must be a valid argument to

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    /// [`CoapFfiRcCell<CoapServerSessionInner>::clone_raw_rc`](CoapFfiRcCell::clone_raw_rc).

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    pub(crate) unsafe fn from_raw_without_refcount<'a>(raw_session: *mut coap_session_t) -> CoapServerSession<'a> {

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        assert!(!raw_session.is_null(), "provided raw session was null");

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        let raw_session_type = coap_session_get_type(raw_session);

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        match raw_session_type {

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            coap_session_type_t::COAP_SESSION_TYPE_NONE => panic!("provided session has no type"),

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            coap_session_type_t::COAP_SESSION_TYPE_SERVER | coap_session_type_t::COAP_SESSION_TYPE_HELLO => {

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                let raw_app_data_ptr = coap_session_get_app_data(raw_session);

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                assert!(!raw_app_data_ptr.is_null(), "provided raw session has no app data");

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                CoapServerSession {

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                    inner: CoapFfiRcCell::clone_raw_rc(raw_app_data_ptr),

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                    ref_counted: false,

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},

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            coap_session_type_t::COAP_SESSION_TYPE_CLIENT => {

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                panic!("attempted to create CoapServerSession from raw client session")

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},

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            _ => unreachable!("unknown session type"),

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impl<'a> Drop for CoapServerSession<'a> {

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    fn drop(&mut self) {

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        let raw_session = self.inner.borrow_mut().inner.raw_session;

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        // Decrease libcoap-internal reference counter for raw session so that we don't leak memory

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        // if we previously incremented the reference count.

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        if self.ref_counted {

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            // SAFETY: raw_session is always valid for the lifetime of this object.

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            unsafe {

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                coap_session_release(raw_session);

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impl<'a> CoapSessionInnerProvider<'a> for CoapServerSession<'a> {

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    fn inner_ref<'b>(&'b self) -> Ref<'b, CoapSessionInner<'a>> {

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        Ref::map(self.inner.borrow(), |v| &v.inner)

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    fn inner_mut<'b>(&'b self) -> RefMut<'b, CoapSessionInner<'a>> {

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        RefMut::map(self.inner.borrow_mut(), |v| &mut v.inner)

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impl<'a, T: CoapSessionCommon<'a>> PartialEq<T> for CoapServerSession<'_> {

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    fn eq(&self, other: &T) -> bool {

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        // SAFETY: Pointers are only compared, never accessed.

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        self.if_index() == other.if_index()

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            && unsafe { self.raw_session() == other.raw_session() }

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            && self.addr_local() == other.addr_local()

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            && self.addr_remote() == other.addr_remote()

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impl Eq for CoapServerSession<'_> {}

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impl Drop for CoapServerSessionInner<'_> {

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    fn drop(&mut self) {

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        unsafe {

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            let app_data = coap_session_get_app_data(self.inner.raw_session);

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            assert!(!app_data.is_null());

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            std::mem::drop(CoapFfiRcCell::<CoapServerSessionInner>::raw_ptr_to_weak(app_data));

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