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</pre><pre class="rust ">
<span class="kw">use</span> <span class="ident">core</span>::<span class="ident">fmt</span>;
<span class="kw">use</span> <span class="ident">core</span>::<span class="ident">marker</span>::<span class="ident">PhantomData</span>;
<span class="kw">use</span> {<span class="ident">Poll</span>, <span class="ident">Future</span>, <span class="ident">Stream</span>, <span class="ident">Sink</span>, <span class="ident">StartSend</span>};
<span class="kw">mod</span> <span class="ident">atomic_task</span>;
<span class="kw">pub</span> <span class="kw">use</span> <span class="self">self</span>::<span class="ident">atomic_task</span>::<span class="ident">AtomicTask</span>;
<span class="kw">mod</span> <span class="ident">core</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"use_std"</span>)]</span>
<span class="kw">mod</span> <span class="ident">std</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"use_std"</span>)]</span>
<span class="kw">pub</span> <span class="kw">use</span> <span class="self">self</span>::<span class="ident">std</span>::<span class="kw-2">*</span>;
<span class="attribute">#[<span class="ident">cfg</span>(<span class="ident">not</span>(<span class="ident">feature</span> <span class="op">=</span> <span class="string">"use_std"</span>))]</span>
<span class="kw">pub</span> <span class="kw">use</span> <span class="self">self</span>::<span class="ident">core</span>::<span class="kw-2">*</span>;
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">BorrowedTask</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span> {
<span class="ident">id</span>: <span class="ident">usize</span>,
<span class="ident">unpark</span>: <span class="ident">BorrowedUnpark</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>,
<span class="ident">events</span>: <span class="ident">BorrowedEvents</span><span class="op"><</span><span class="lifetime">'a</span><span class="op">></span>,
<span class="comment">// Task-local storage</span>
<span class="ident">map</span>: <span class="kw-2">&</span><span class="lifetime">'a</span> <span class="ident">LocalMap</span>,
}
<span class="kw">fn</span> <span class="ident">fresh_task_id</span>() <span class="op">-></span> <span class="ident">usize</span> {
<span class="kw">use</span> <span class="ident">core</span>::<span class="ident">sync</span>::<span class="ident">atomic</span>::{<span class="ident">AtomicUsize</span>, <span class="ident">Ordering</span>, <span class="ident">ATOMIC_USIZE_INIT</span>};
<span class="comment">// TODO: this assert is a real bummer, need to figure out how to reuse</span>
<span class="comment">// old IDs that are no longer in use.</span>
<span class="comment">//</span>
<span class="comment">// Note, though, that it is intended that these ids go away entirely</span>
<span class="comment">// eventually, see the comment on `is_current` below.</span>
<span class="kw">static</span> <span class="ident">NEXT_ID</span>: <span class="ident">AtomicUsize</span> <span class="op">=</span> <span class="ident">ATOMIC_USIZE_INIT</span>;
<span class="kw">let</span> <span class="ident">id</span> <span class="op">=</span> <span class="ident">NEXT_ID</span>.<span class="ident">fetch_add</span>(<span class="number">1</span>, <span class="ident">Ordering</span>::<span class="ident">Relaxed</span>);
<span class="macro">assert</span><span class="macro">!</span>(<span class="ident">id</span> <span class="op"><</span> <span class="ident">usize</span>::<span class="ident">max_value</span>() <span class="op">/</span> <span class="number">2</span>,
<span class="string">"too many previous tasks have been allocated"</span>);
<span class="ident">id</span>
}
<span class="kw">fn</span> <span class="ident">with</span><span class="op"><</span><span class="ident">F</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="ident">BorrowedTask</span>) <span class="op">-></span> <span class="ident">R</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">f</span>: <span class="ident">F</span>) <span class="op">-></span> <span class="ident">R</span> {
<span class="kw">unsafe</span> {
<span class="kw">let</span> <span class="ident">task</span> <span class="op">=</span> <span class="ident">get_ptr</span>();
<span class="macro">assert</span><span class="macro">!</span>(<span class="op">!</span><span class="ident">task</span>.<span class="ident">is_null</span>(), <span class="string">"no Task is currently running"</span>);
<span class="ident">f</span>(<span class="kw-2">&</span><span class="kw-2">*</span>(<span class="ident">task</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">BorrowedTask</span>))
}
}
<span class="doccomment">/// A handle to a "task", which represents a single lightweight "thread" of</span>
<span class="doccomment">/// execution driving a future to completion.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// In general, futures are composed into large units of work, which are then</span>
<span class="doccomment">/// spawned as tasks onto an *executor*. The executor is responsible for polling</span>
<span class="doccomment">/// the future as notifications arrive, until the future terminates.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is obtained by the `task::current` function.</span>
<span class="attribute">#[<span class="ident">derive</span>(<span class="ident">Clone</span>)]</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Task</span> {
<span class="ident">id</span>: <span class="ident">usize</span>,
<span class="ident">unpark</span>: <span class="ident">TaskUnpark</span>,
<span class="ident">events</span>: <span class="ident">UnparkEvents</span>,
}
<span class="kw">fn</span> <span class="ident">_assert_kinds</span>() {
<span class="kw">fn</span> <span class="ident">_assert_send</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Send</span><span class="op">></span>() {}
<span class="ident">_assert_send</span>::<span class="op"><</span><span class="ident">Task</span><span class="op">></span>();
}
<span class="doccomment">/// Returns a handle to the current task to call `notify` at a later date.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The returned handle implements the `Send` and `'static` bounds and may also</span>
<span class="doccomment">/// be cheaply cloned. This is useful for squirreling away the handle into a</span>
<span class="doccomment">/// location which is then later signaled that a future can make progress.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Implementations of the `Future` trait typically use this function if they</span>
<span class="doccomment">/// would otherwise perform a blocking operation. When something isn't ready</span>
<span class="doccomment">/// yet, this `current` function is called to acquire a handle to the current</span>
<span class="doccomment">/// task, and then the future arranges it such that when the blocking operation</span>
<span class="doccomment">/// otherwise finishes (perhaps in the background) it will `notify` the</span>
<span class="doccomment">/// returned handle.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// It's sometimes necessary to pass extra information to the task when</span>
<span class="doccomment">/// unparking it, so that the task knows something about *why* it was woken.</span>
<span class="doccomment">/// See the `FutureQueue` documentation for details on how to do this.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Panics</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function will panic if a task is not currently being executed. That</span>
<span class="doccomment">/// is, this method can be dangerous to call outside of an implementation of</span>
<span class="doccomment">/// `poll`.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">current</span>() <span class="op">-></span> <span class="ident">Task</span> {
<span class="ident">with</span>(<span class="op">|</span><span class="ident">borrowed</span><span class="op">|</span> {
<span class="kw">let</span> <span class="ident">unpark</span> <span class="op">=</span> <span class="ident">borrowed</span>.<span class="ident">unpark</span>.<span class="ident">to_owned</span>();
<span class="kw">let</span> <span class="ident">events</span> <span class="op">=</span> <span class="ident">borrowed</span>.<span class="ident">events</span>.<span class="ident">to_owned</span>();
<span class="ident">Task</span> {
<span class="ident">id</span>: <span class="ident">borrowed</span>.<span class="ident">id</span>,
<span class="ident">unpark</span>: <span class="ident">unpark</span>,
<span class="ident">events</span>: <span class="ident">events</span>,
}
})
}
<span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span>
<span class="attribute">#[<span class="ident">deprecated</span>(<span class="ident">note</span> <span class="op">=</span> <span class="string">"renamed to `current`"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">park</span>() <span class="op">-></span> <span class="ident">Task</span> {
<span class="ident">current</span>()
}
<span class="kw">impl</span> <span class="ident">Task</span> {
<span class="doccomment">/// Indicate that the task should attempt to poll its future in a timely</span>
<span class="doccomment">/// fashion.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// It's typically guaranteed that, for each call to `notify`, `poll` will</span>
<span class="doccomment">/// be called at least once subsequently (unless the future has terminated).</span>
<span class="doccomment">/// If the task is currently polling its future when `notify` is called, it</span>
<span class="doccomment">/// must poll the future *again* afterwards, ensuring that all relevant</span>
<span class="doccomment">/// events are eventually observed by the future.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">notify</span>(<span class="kw-2">&</span><span class="self">self</span>) {
<span class="self">self</span>.<span class="ident">events</span>.<span class="ident">notify</span>();
<span class="self">self</span>.<span class="ident">unpark</span>.<span class="ident">notify</span>();
}
<span class="attribute">#[<span class="ident">doc</span>(<span class="ident">hidden</span>)]</span>
<span class="attribute">#[<span class="ident">deprecated</span>(<span class="ident">note</span> <span class="op">=</span> <span class="string">"renamed to `notify`"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">unpark</span>(<span class="kw-2">&</span><span class="self">self</span>) {
<span class="self">self</span>.<span class="ident">notify</span>()
}
<span class="doccomment">/// Returns `true` when called from within the context of the task.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// In other words, the task is currently running on the thread calling the</span>
<span class="doccomment">/// function. Note that this is currently, and has historically, been</span>
<span class="doccomment">/// implemented by tracking an `id` on every instance of `Spawn` created.</span>
<span class="doccomment">/// When a `Spawn` is being polled it stores in thread-local-storage the id</span>
<span class="doccomment">/// of the instance, and then `task::current` will return a `Task` that also</span>
<span class="doccomment">/// stores this id.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The intention of this function was to answer questions like "if I</span>
<span class="doccomment">/// `notify` this task, is it equivalent to `task::current().notify()`?"</span>
<span class="doccomment">/// The answer "yes" may be able to avoid some extra work to block the</span>
<span class="doccomment">/// current task, such as sending a task along a channel or updating a</span>
<span class="doccomment">/// stored `Task` somewhere. An answer of "no" typically results in doing</span>
<span class="doccomment">/// the work anyway.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Unfortunately this function has been somewhat buggy in the past and is</span>
<span class="doccomment">/// not intended to be supported in the future. By simply matching `id` the</span>
<span class="doccomment">/// intended question above isn't accurately taking into account, for</span>
<span class="doccomment">/// example, unpark events (now deprecated, but still a feature). Thus many</span>
<span class="doccomment">/// old users of this API weren't fully accounting for the question it was</span>
<span class="doccomment">/// intended they were asking.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This API continues to be implemented but will in the future, e.g. in the</span>
<span class="doccomment">/// 0.1.x series of this crate, eventually return `false` unconditionally.</span>
<span class="doccomment">/// It is intended that this function will be removed in the next breaking</span>
<span class="doccomment">/// change of this crate. If you'd like to continue to be able to answer the</span>
<span class="doccomment">/// example question above, it's recommended you use the</span>
<span class="doccomment">/// `will_notify_current` method.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If you've got questions about this though please let us know! We'd like</span>
<span class="doccomment">/// to learn about other use cases here that we did not consider.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Panics</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function will panic if no current future is being polled.</span>
<span class="attribute">#[<span class="ident">deprecated</span>(<span class="ident">note</span> <span class="op">=</span> <span class="string">"intended to be removed, see docs for details"</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">is_current</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">bool</span> {
<span class="ident">with</span>(<span class="op">|</span><span class="ident">current</span><span class="op">|</span> <span class="ident">current</span>.<span class="ident">id</span> <span class="op">==</span> <span class="self">self</span>.<span class="ident">id</span>)
}
<span class="doccomment">/// This function is intended as a performance optimization for structures</span>
<span class="doccomment">/// which store a `Task` internally.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The purpose of this function is to answer the question "if I `notify`</span>
<span class="doccomment">/// this task is it equivalent to `task::current().notify()`". An answer</span>
<span class="doccomment">/// "yes" may mean that you don't actually need to call `task::current()`</span>
<span class="doccomment">/// and store it, but rather you can simply leave a stored task in place. An</span>
<span class="doccomment">/// answer of "no" typically means that you need to call `task::current()`</span>
<span class="doccomment">/// and store it somewhere.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// As this is purely a peformance optimization a valid implementation for</span>
<span class="doccomment">/// this function is to always return `false`. A best effort is done to</span>
<span class="doccomment">/// return `true` where possible, but false negatives may happen. Note that</span>
<span class="doccomment">/// this function will not return a false positive, however.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Panics</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function will panic if no current future is being polled.</span>
<span class="attribute">#[<span class="ident">allow</span>(<span class="ident">deprecated</span>)]</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">will_notify_current</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">bool</span> {
<span class="ident">with</span>(<span class="op">|</span><span class="ident">current</span><span class="op">|</span> {
<span class="self">self</span>.<span class="ident">unpark</span>.<span class="ident">will_notify</span>(<span class="kw-2">&</span><span class="ident">current</span>.<span class="ident">unpark</span>) <span class="op">&&</span>
<span class="self">self</span>.<span class="ident">events</span>.<span class="ident">will_notify</span>(<span class="kw-2">&</span><span class="ident">current</span>.<span class="ident">events</span>)
})
}
}
<span class="kw">impl</span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">Task</span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
<span class="ident">f</span>.<span class="ident">debug_struct</span>(<span class="string">"Task"</span>)
.<span class="ident">finish</span>()
}
}
<span class="doccomment">/// Representation of a spawned future/stream.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This object is returned by the `spawn` function in this module. This</span>
<span class="doccomment">/// represents a "fused task and future", storing all necessary pieces of a task</span>
<span class="doccomment">/// and owning the top-level future that's being driven as well.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A `Spawn` can be poll'd for completion or execution of the current thread</span>
<span class="doccomment">/// can be blocked indefinitely until a notification arrives. This can be used</span>
<span class="doccomment">/// with either futures or streams, with different methods being available on</span>
<span class="doccomment">/// `Spawn` depending which is used.</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">Spawn</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">id</span>: <span class="ident">usize</span>,
<span class="ident">obj</span>: <span class="ident">T</span>,
<span class="ident">data</span>: <span class="ident">LocalMap</span>,
}
<span class="doccomment">/// Spawns a new future, returning the fused future and task.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function is the termination endpoint for running futures. This method</span>
<span class="doccomment">/// will conceptually allocate a new task to run the given object, which is</span>
<span class="doccomment">/// normally either a `Future` or `Stream`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function is similar to the `thread::spawn` function but does not</span>
<span class="doccomment">/// attempt to run code in the background. The future will not make progress</span>
<span class="doccomment">/// until the methods on `Spawn` are called in turn.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">spawn</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="ident">obj</span>: <span class="ident">T</span>) <span class="op">-></span> <span class="ident">Spawn</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="ident">Spawn</span> {
<span class="ident">id</span>: <span class="ident">fresh_task_id</span>(),
<span class="ident">obj</span>: <span class="ident">obj</span>,
<span class="ident">data</span>: <span class="ident">local_map</span>(),
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Spawn</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="doccomment">/// Get a shared reference to the object the Spawn is wrapping.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_ref</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="ident">T</span> {
<span class="kw-2">&</span><span class="self">self</span>.<span class="ident">obj</span>
}
<span class="doccomment">/// Get a mutable reference to the object the Spawn is wrapping.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">get_mut</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) <span class="op">-></span> <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">T</span> {
<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">obj</span>
}
<span class="doccomment">/// Consume the Spawn, returning its inner object</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">into_inner</span>(<span class="self">self</span>) <span class="op">-></span> <span class="ident">T</span> {
<span class="self">self</span>.<span class="ident">obj</span>
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">F</span>: <span class="ident">Future</span><span class="op">></span> <span class="ident">Spawn</span><span class="op"><</span><span class="ident">F</span><span class="op">></span> {
<span class="doccomment">/// Polls the internal future, scheduling notifications to be sent to the</span>
<span class="doccomment">/// `notify` argument.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This method will poll the internal future, testing if it's completed</span>
<span class="doccomment">/// yet. The `notify` argument is used as a sink for notifications sent to</span>
<span class="doccomment">/// this future. That is, while the future is being polled, any call to</span>
<span class="doccomment">/// `task::current()` will return a handle that contains the `notify`</span>
<span class="doccomment">/// specified.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If this function returns `NotReady`, then the `notify` should have been</span>
<span class="doccomment">/// scheduled to receive a notification when poll can be called again.</span>
<span class="doccomment">/// Otherwise if `Ready` or `Err` is returned, the `Spawn` task can be</span>
<span class="doccomment">/// safely destroyed.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that `notify` itself is passed as a shared reference, and is itself</span>
<span class="doccomment">/// not required to be a `NotifyHandle`. The `Clone` and `Into` trait bounds</span>
<span class="doccomment">/// will be used to convert this `notify` to a `NotifyHandle` if necessary.</span>
<span class="doccomment">/// This construction can avoid an unnecessary atomic reference count bump</span>
<span class="doccomment">/// in some situations.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ## Unsafety and `id`</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function and all other `*_notify` functions on this type will treat</span>
<span class="doccomment">/// the `id` specified very carefully, explicitly calling functions like the</span>
<span class="doccomment">/// `notify` argument's `clone_id` and `drop_id` functions. It should be</span>
<span class="doccomment">/// safe to encode a pointer itself into the `id` specified, such as an</span>
<span class="doccomment">/// `Arc<T>` or a `Box<T>`. The `clone_id` and `drop_id` functions are then</span>
<span class="doccomment">/// intended to be sufficient for the memory management related to that</span>
<span class="doccomment">/// pointer.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">poll_future_notify</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>,
<span class="ident">notify</span>: <span class="kw-2">&</span><span class="ident">T</span>,
<span class="ident">id</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">Poll</span><span class="op"><</span><span class="ident">F</span>::<span class="ident">Item</span>, <span class="ident">F</span>::<span class="ident">Error</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">T</span>: <span class="ident">Clone</span> <span class="op">+</span> <span class="ident">Into</span><span class="op"><</span><span class="ident">NotifyHandle</span><span class="op">></span>,
{
<span class="kw">let</span> <span class="ident">mk</span> <span class="op">=</span> <span class="op">||</span> <span class="ident">notify</span>.<span class="ident">clone</span>().<span class="ident">into</span>();
<span class="self">self</span>.<span class="ident">enter</span>(<span class="ident">BorrowedUnpark</span>::<span class="ident">new</span>(<span class="kw-2">&</span><span class="ident">mk</span>, <span class="ident">id</span>), <span class="op">|</span><span class="ident">f</span><span class="op">|</span> <span class="ident">f</span>.<span class="ident">poll</span>())
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">S</span>: <span class="ident">Stream</span><span class="op">></span> <span class="ident">Spawn</span><span class="op"><</span><span class="ident">S</span><span class="op">></span> {
<span class="doccomment">/// Like `poll_future_notify`, except polls the underlying stream.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">poll_stream_notify</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>,
<span class="ident">notify</span>: <span class="kw-2">&</span><span class="ident">T</span>,
<span class="ident">id</span>: <span class="ident">usize</span>)
<span class="op">-></span> <span class="ident">Poll</span><span class="op"><</span><span class="prelude-ty">Option</span><span class="op"><</span><span class="ident">S</span>::<span class="ident">Item</span><span class="op">></span>, <span class="ident">S</span>::<span class="ident">Error</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">T</span>: <span class="ident">Clone</span> <span class="op">+</span> <span class="ident">Into</span><span class="op"><</span><span class="ident">NotifyHandle</span><span class="op">></span>,
{
<span class="kw">let</span> <span class="ident">mk</span> <span class="op">=</span> <span class="op">||</span> <span class="ident">notify</span>.<span class="ident">clone</span>().<span class="ident">into</span>();
<span class="self">self</span>.<span class="ident">enter</span>(<span class="ident">BorrowedUnpark</span>::<span class="ident">new</span>(<span class="kw-2">&</span><span class="ident">mk</span>, <span class="ident">id</span>), <span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>.<span class="ident">poll</span>())
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">S</span>: <span class="ident">Sink</span><span class="op">></span> <span class="ident">Spawn</span><span class="op"><</span><span class="ident">S</span><span class="op">></span> {
<span class="doccomment">/// Invokes the underlying `start_send` method with this task in place.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the underlying operation returns `NotReady` then the `notify` value</span>
<span class="doccomment">/// passed in will receive a notification when the operation is ready to be</span>
<span class="doccomment">/// attempted again.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">start_send_notify</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>,
<span class="ident">value</span>: <span class="ident">S</span>::<span class="ident">SinkItem</span>,
<span class="ident">notify</span>: <span class="kw-2">&</span><span class="ident">T</span>,
<span class="ident">id</span>: <span class="ident">usize</span>)
<span class="op">-></span> <span class="ident">StartSend</span><span class="op"><</span><span class="ident">S</span>::<span class="ident">SinkItem</span>, <span class="ident">S</span>::<span class="ident">SinkError</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">T</span>: <span class="ident">Clone</span> <span class="op">+</span> <span class="ident">Into</span><span class="op"><</span><span class="ident">NotifyHandle</span><span class="op">></span>,
{
<span class="kw">let</span> <span class="ident">mk</span> <span class="op">=</span> <span class="op">||</span> <span class="ident">notify</span>.<span class="ident">clone</span>().<span class="ident">into</span>();
<span class="self">self</span>.<span class="ident">enter</span>(<span class="ident">BorrowedUnpark</span>::<span class="ident">new</span>(<span class="kw-2">&</span><span class="ident">mk</span>, <span class="ident">id</span>), <span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>.<span class="ident">start_send</span>(<span class="ident">value</span>))
}
<span class="doccomment">/// Invokes the underlying `poll_complete` method with this task in place.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If the underlying operation returns `NotReady` then the `notify` value</span>
<span class="doccomment">/// passed in will receive a notification when the operation is ready to be</span>
<span class="doccomment">/// attempted again.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">poll_flush_notify</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>,
<span class="ident">notify</span>: <span class="kw-2">&</span><span class="ident">T</span>,
<span class="ident">id</span>: <span class="ident">usize</span>)
<span class="op">-></span> <span class="ident">Poll</span><span class="op"><</span>(), <span class="ident">S</span>::<span class="ident">SinkError</span><span class="op">></span>
<span class="kw">where</span> <span class="ident">T</span>: <span class="ident">Clone</span> <span class="op">+</span> <span class="ident">Into</span><span class="op"><</span><span class="ident">NotifyHandle</span><span class="op">></span>,
{
<span class="kw">let</span> <span class="ident">mk</span> <span class="op">=</span> <span class="op">||</span> <span class="ident">notify</span>.<span class="ident">clone</span>().<span class="ident">into</span>();
<span class="self">self</span>.<span class="ident">enter</span>(<span class="ident">BorrowedUnpark</span>::<span class="ident">new</span>(<span class="kw-2">&</span><span class="ident">mk</span>, <span class="ident">id</span>), <span class="op">|</span><span class="ident">s</span><span class="op">|</span> <span class="ident">s</span>.<span class="ident">poll_complete</span>())
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> <span class="ident">Spawn</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">enter</span><span class="op"><</span><span class="ident">F</span>, <span class="ident">R</span><span class="op">></span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>, <span class="ident">unpark</span>: <span class="ident">BorrowedUnpark</span>, <span class="ident">f</span>: <span class="ident">F</span>) <span class="op">-></span> <span class="ident">R</span>
<span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnOnce</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">T</span>) <span class="op">-></span> <span class="ident">R</span>
{
<span class="kw">let</span> <span class="ident">borrowed</span> <span class="op">=</span> <span class="ident">BorrowedTask</span> {
<span class="ident">id</span>: <span class="self">self</span>.<span class="ident">id</span>,
<span class="ident">unpark</span>: <span class="ident">unpark</span>,
<span class="ident">events</span>: <span class="ident">BorrowedEvents</span>::<span class="ident">new</span>(),
<span class="ident">map</span>: <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">data</span>,
};
<span class="kw">let</span> <span class="ident">obj</span> <span class="op">=</span> <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>.<span class="ident">obj</span>;
<span class="ident">set</span>(<span class="kw-2">&</span><span class="ident">borrowed</span>, <span class="op">||</span> <span class="ident">f</span>(<span class="ident">obj</span>))
}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">fmt</span>::<span class="ident">Debug</span><span class="op">></span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">Spawn</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
<span class="ident">f</span>.<span class="ident">debug_struct</span>(<span class="string">"Spawn"</span>)
.<span class="ident">field</span>(<span class="string">"obj"</span>, <span class="kw-2">&</span><span class="self">self</span>.<span class="ident">obj</span>)
.<span class="ident">finish</span>()
}
}
<span class="doccomment">/// A trait which represents a sink of notifications that a future is ready to</span>
<span class="doccomment">/// make progress.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This trait is provided as an argument to the `Spawn::*_notify` family of</span>
<span class="doccomment">/// functions. It's transitively used as part of the `Task::notify` method to</span>
<span class="doccomment">/// internally deliver notifications of readiness of a future to move forward.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// An instance of `Notify` has one primary method, `notify`, which is given a</span>
<span class="doccomment">/// contextual argument as to what's being notified. This contextual argument is</span>
<span class="doccomment">/// *also* provided to the `Spawn::*_notify` family of functions and can be used</span>
<span class="doccomment">/// to reuse an instance of `Notify` across many futures.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Instances of `Notify` must be safe to share across threads, and the methods</span>
<span class="doccomment">/// be invoked concurrently. They must also live for the `'static` lifetime,</span>
<span class="doccomment">/// not containing any stack references.</span>
<span class="kw">pub</span> <span class="kw">trait</span> <span class="ident">Notify</span>: <span class="ident">Send</span> <span class="op">+</span> <span class="ident">Sync</span> {
<span class="doccomment">/// Indicates that an associated future and/or task are ready to make</span>
<span class="doccomment">/// progress.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Typically this means that the receiver of the notification should</span>
<span class="doccomment">/// arrange for the future to get poll'd in a prompt fashion.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This method takes an `id` as an argument which was transitively passed</span>
<span class="doccomment">/// in from the original call to `Spawn::*_notify`. This id can be used to</span>
<span class="doccomment">/// disambiguate which precise future became ready for polling.</span>
<span class="kw">fn</span> <span class="ident">notify</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">usize</span>);
<span class="doccomment">/// This function is called whenever a new copy of `id` is needed.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This is called in one of two situations:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// * A `Task` is being created through `task::current` while a future is</span>
<span class="doccomment">/// being polled. In that case the instance of `Notify` passed in to one</span>
<span class="doccomment">/// of the `poll_*` functions is called with the `id` passed into the same</span>
<span class="doccomment">/// `poll_*` function.</span>
<span class="doccomment">/// * A `Task` is itself being cloned. Each `Task` contains its own id and a</span>
<span class="doccomment">/// handle to the `Notify` behind it, and the task's `Notify` is used to</span>
<span class="doccomment">/// clone the internal `id` to assign to the new task.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The `id` returned here will be stored in the `Task`-to-be and used later</span>
<span class="doccomment">/// to pass to `notify` when the `Task::notify` function is called on that</span>
<span class="doccomment">/// `Task`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that typically this is just the identity function, passing through</span>
<span class="doccomment">/// the identifier. For more unsafe situations, however, if `id` is itself a</span>
<span class="doccomment">/// pointer of some kind this can be used as a hook to "clone" the pointer,</span>
<span class="doccomment">/// depending on what that means for the specified pointer.</span>
<span class="kw">fn</span> <span class="ident">clone_id</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">usize</span> {
<span class="ident">id</span>
}
<span class="doccomment">/// All instances of `Task` store an `id` that they're going to internally</span>
<span class="doccomment">/// notify with, and this function is called when the `Task` is dropped.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function provides a hook for schemes which encode pointers in this</span>
<span class="doccomment">/// `id` argument to deallocate resources associated with the pointer. It's</span>
<span class="doccomment">/// guaranteed that after this function is called the `Task` containing this</span>
<span class="doccomment">/// `id` will no longer use the `id`.</span>
<span class="kw">fn</span> <span class="ident">drop_id</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">usize</span>) {
<span class="ident">drop</span>(<span class="ident">id</span>);
}
}
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">with_notify</span><span class="op"><</span><span class="ident">F</span>, <span class="ident">T</span>, <span class="ident">R</span><span class="op">></span>(<span class="ident">notify</span>: <span class="kw-2">&</span><span class="ident">T</span>, <span class="ident">id</span>: <span class="ident">usize</span>, <span class="ident">f</span>: <span class="ident">F</span>) <span class="op">-></span> <span class="ident">R</span>
<span class="kw">where</span> <span class="ident">F</span>: <span class="ident">FnOnce</span>() <span class="op">-></span> <span class="ident">R</span>,
<span class="ident">T</span>: <span class="ident">Clone</span> <span class="op">+</span> <span class="ident">Into</span><span class="op"><</span><span class="ident">NotifyHandle</span><span class="op">></span>,
{
<span class="ident">with</span>(<span class="op">|</span><span class="ident">task</span><span class="op">|</span> {
<span class="kw">let</span> <span class="ident">mk</span> <span class="op">=</span> <span class="op">||</span> <span class="ident">notify</span>.<span class="ident">clone</span>().<span class="ident">into</span>();
<span class="kw">let</span> <span class="ident">new_task</span> <span class="op">=</span> <span class="ident">BorrowedTask</span> {
<span class="ident">id</span>: <span class="ident">task</span>.<span class="ident">id</span>,
<span class="ident">unpark</span>: <span class="ident">BorrowedUnpark</span>::<span class="ident">new</span>(<span class="kw-2">&</span><span class="ident">mk</span>, <span class="ident">id</span>),
<span class="ident">events</span>: <span class="ident">task</span>.<span class="ident">events</span>,
<span class="ident">map</span>: <span class="ident">task</span>.<span class="ident">map</span>,
};
<span class="ident">set</span>(<span class="kw-2">&</span><span class="ident">new_task</span>, <span class="ident">f</span>)
})
}
<span class="doccomment">/// An unsafe trait for implementing custom forms of memory management behind a</span>
<span class="doccomment">/// `Task`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The `futures` critically relies on "notification handles" to extract for</span>
<span class="doccomment">/// futures to contain and then later inform that they're ready to make</span>
<span class="doccomment">/// progress. These handles, however, must be cheap to create and cheap</span>
<span class="doccomment">/// to clone to ensure that this operation is efficient throughout the</span>
<span class="doccomment">/// execution of a program.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Typically this sort of memory management is done in the standard library</span>
<span class="doccomment">/// with the `Arc` type. An `Arc` is relatively cheap to allocate an is</span>
<span class="doccomment">/// quite cheap to clone and pass around. Plus, it's 100% safe!</span>
<span class="doccomment">///</span>
<span class="doccomment">/// When working outside the standard library, however, you don't always have</span>
<span class="doccomment">/// and `Arc` type available to you. This trait, `UnsafeNotify`, is intended</span>
<span class="doccomment">/// to be the "unsafe version" of the `Notify` trait. This trait encodes the</span>
<span class="doccomment">/// memory management operations of a `Task`'s notification handle, allowing</span>
<span class="doccomment">/// custom implementations for the memory management of a notification handle.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Put another way, the core notification type in this library,</span>
<span class="doccomment">/// `NotifyHandle`, simply internally contains an instance of</span>
<span class="doccomment">/// `*mut UnsafeNotify`. This "unsafe trait object" is then used exclusively</span>
<span class="doccomment">/// to operate with, dynamically dispatching calls to clone, drop, and notify.</span>
<span class="doccomment">/// Critically though as a raw pointer it doesn't require a particular form</span>
<span class="doccomment">/// of memory management, allowing external implementations.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// A default implementation of the `UnsafeNotify` trait is provided for the</span>
<span class="doccomment">/// `Arc` type in the standard library. If the `use_std` feature of this crate</span>
<span class="doccomment">/// is not available however, you'll be required to implement your own</span>
<span class="doccomment">/// instance of this trait to pass it into `NotifyHandle::new`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Unsafety</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This trait is manually encoding the memory management of the underlying</span>
<span class="doccomment">/// handle, and as a result is quite unsafe to implement! Implementors of</span>
<span class="doccomment">/// this trait must guarantee:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// * Calls to `clone_raw` produce uniquely owned handles. It should be safe</span>
<span class="doccomment">/// to drop the current handle and have the returned handle still be valid.</span>
<span class="doccomment">/// * Calls to `drop_raw` work with `self` as a raw pointer, deallocating</span>
<span class="doccomment">/// resources associated with it. This is a pretty unsafe operation as it's</span>
<span class="doccomment">/// invalidating the `self` pointer, so extreme care needs to be taken.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// In general it's recommended to review the trait documentation as well as</span>
<span class="doccomment">/// the implementation for `Arc` in this crate. When in doubt ping the</span>
<span class="doccomment">/// `futures` authors to clarify an unsafety question here.</span>
<span class="kw">pub</span> <span class="kw">unsafe</span> <span class="kw">trait</span> <span class="ident">UnsafeNotify</span>: <span class="ident">Notify</span> {
<span class="doccomment">/// Creates a new `NotifyHandle` from this instance of `UnsafeNotify`.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This function will create a new uniquely owned handle that under the</span>
<span class="doccomment">/// hood references the same notification instance. In other words calls</span>
<span class="doccomment">/// to `notify` on the returned handle should be equivalent to calls to</span>
<span class="doccomment">/// `notify` on this handle.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Unsafety</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This trait is unsafe to implement, as are all these methods. This</span>
<span class="doccomment">/// method is also unsafe to call as it's asserting the `UnsafeNotify`</span>
<span class="doccomment">/// value is in a consistent state. In general it's recommended to</span>
<span class="doccomment">/// review the trait documentation as well as the implementation for `Arc`</span>
<span class="doccomment">/// in this crate. When in doubt ping the `futures` authors to clarify</span>
<span class="doccomment">/// an unsafety question here.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">clone_raw</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">NotifyHandle</span>;
<span class="doccomment">/// Drops this instance of `UnsafeNotify`, deallocating resources</span>
<span class="doccomment">/// associated with it.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This method is intended to have a signature such as:</span>
<span class="doccomment">///</span>
<span class="doccomment">/// ```ignore</span>
<span class="doccomment">/// fn drop_raw(self: *mut Self);</span>
<span class="doccomment">/// ```</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Unfortunately in Rust today that signature is not object safe.</span>
<span class="doccomment">/// Nevertheless it's recommended to implement this function *as if* that</span>
<span class="doccomment">/// were its signature. As such it is not safe to call on an invalid</span>
<span class="doccomment">/// pointer, nor is the validity of the pointer guaranteed after this</span>
<span class="doccomment">/// function returns.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// # Unsafety</span>
<span class="doccomment">///</span>
<span class="doccomment">/// This trait is unsafe to implement, as are all these methods. This</span>
<span class="doccomment">/// method is also unsafe to call as it's asserting the `UnsafeNotify`</span>
<span class="doccomment">/// value is in a consistent state. In general it's recommended to</span>
<span class="doccomment">/// review the trait documentation as well as the implementation for `Arc`</span>
<span class="doccomment">/// in this crate. When in doubt ping the `futures` authors to clarify</span>
<span class="doccomment">/// an unsafety question here.</span>
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">drop_raw</span>(<span class="kw-2">&</span><span class="self">self</span>);
}
<span class="doccomment">/// A `NotifyHandle` is the core value through which notifications are routed</span>
<span class="doccomment">/// in the `futures` crate.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// All instances of `Task` will contain a `NotifyHandle` handle internally.</span>
<span class="doccomment">/// This handle itself contains a trait object pointing to an instance of the</span>
<span class="doccomment">/// `Notify` trait, allowing notifications to get routed through it.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// The `NotifyHandle` type internally does not codify any particular memory</span>
<span class="doccomment">/// management strategy. Internally it contains an instance of `*mut</span>
<span class="doccomment">/// UnsafeNotify`, and more details about that trait can be found on its own</span>
<span class="doccomment">/// documentation. Consequently, though, the one constructor of this type,</span>
<span class="doccomment">/// `NotifyHandle::new`, is `unsafe` to call. It is not recommended to call</span>
<span class="doccomment">/// this constructor directly.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If you're working with the standard library then it's recommended to</span>
<span class="doccomment">/// work with the `Arc` type. If you have a struct, `T`, which implements the</span>
<span class="doccomment">/// `Notify` trait, then you can construct this with</span>
<span class="doccomment">/// `NotifyHandle::from(t: Arc<T>)`. The coercion to `UnsafeNotify` will</span>
<span class="doccomment">/// happen automatically and safely for you.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// When working externally from the standard library it's recommended to</span>
<span class="doccomment">/// provide a similar safe constructor for your custom type as opposed to</span>
<span class="doccomment">/// recommending an invocation of `NotifyHandle::new` directly.</span>
<span class="kw">pub</span> <span class="kw">struct</span> <span class="ident">NotifyHandle</span> {
<span class="ident">inner</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">UnsafeNotify</span>,
}
<span class="kw">unsafe</span> <span class="kw">impl</span> <span class="ident">Send</span> <span class="kw">for</span> <span class="ident">NotifyHandle</span> {}
<span class="kw">unsafe</span> <span class="kw">impl</span> <span class="ident">Sync</span> <span class="kw">for</span> <span class="ident">NotifyHandle</span> {}
<span class="kw">impl</span> <span class="ident">NotifyHandle</span> {
<span class="doccomment">/// Constructs a new `NotifyHandle` directly.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// Note that most code will not need to call this. Implementors of the</span>
<span class="doccomment">/// `UnsafeNotify` trait will typically provide a wrapper that calls this</span>
<span class="doccomment">/// but you otherwise shouldn't call it directly.</span>
<span class="doccomment">///</span>
<span class="doccomment">/// If you're working with the standard library then it's recommended to</span>
<span class="doccomment">/// use the `NotifyHandle::from` function instead which works with the safe</span>
<span class="doccomment">/// `Arc` type and the safe `Notify` trait.</span>
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">pub</span> <span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">new</span>(<span class="ident">inner</span>: <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">UnsafeNotify</span>) <span class="op">-></span> <span class="ident">NotifyHandle</span> {
<span class="ident">NotifyHandle</span> { <span class="ident">inner</span>: <span class="ident">inner</span> }
}
<span class="doccomment">/// Invokes the underlying instance of `Notify` with the provided `id`.</span>
<span class="kw">pub</span> <span class="kw">fn</span> <span class="ident">notify</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">usize</span>) {
<span class="kw">unsafe</span> { (<span class="kw-2">*</span><span class="self">self</span>.<span class="ident">inner</span>).<span class="ident">notify</span>(<span class="ident">id</span>) }
}
<span class="kw">fn</span> <span class="ident">clone_id</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">usize</span> {
<span class="kw">unsafe</span> { (<span class="kw-2">*</span><span class="self">self</span>.<span class="ident">inner</span>).<span class="ident">clone_id</span>(<span class="ident">id</span>) }
}
<span class="kw">fn</span> <span class="ident">drop_id</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">usize</span>) {
<span class="kw">unsafe</span> { (<span class="kw-2">*</span><span class="self">self</span>.<span class="ident">inner</span>).<span class="ident">drop_id</span>(<span class="ident">id</span>) }
}
}
<span class="kw">impl</span> <span class="ident">Clone</span> <span class="kw">for</span> <span class="ident">NotifyHandle</span> {
<span class="attribute">#[<span class="ident">inline</span>]</span>
<span class="kw">fn</span> <span class="ident">clone</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="self">Self</span> {
<span class="kw">unsafe</span> {
(<span class="kw-2">*</span><span class="self">self</span>.<span class="ident">inner</span>).<span class="ident">clone_raw</span>()
}
}
}
<span class="kw">impl</span> <span class="ident">fmt</span>::<span class="ident">Debug</span> <span class="kw">for</span> <span class="ident">NotifyHandle</span> {
<span class="kw">fn</span> <span class="ident">fmt</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">f</span>: <span class="kw-2">&</span><span class="kw-2">mut</span> <span class="ident">fmt</span>::<span class="ident">Formatter</span>) <span class="op">-></span> <span class="ident">fmt</span>::<span class="prelude-ty">Result</span> {
<span class="ident">f</span>.<span class="ident">debug_struct</span>(<span class="string">"NotifyHandle"</span>)
.<span class="ident">finish</span>()
}
}
<span class="kw">impl</span> <span class="ident">Drop</span> <span class="kw">for</span> <span class="ident">NotifyHandle</span> {
<span class="kw">fn</span> <span class="ident">drop</span>(<span class="kw-2">&</span><span class="kw-2">mut</span> <span class="self">self</span>) {
<span class="kw">unsafe</span> {
(<span class="kw-2">*</span><span class="self">self</span>.<span class="ident">inner</span>).<span class="ident">drop_raw</span>()
}
}
}
<span class="doccomment">/// Marker for a `T` that is behind &'static.</span>
<span class="kw">struct</span> <span class="ident">StaticRef</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>(<span class="ident">PhantomData</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>);
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Notify</span><span class="op">></span> <span class="ident">Notify</span> <span class="kw">for</span> <span class="ident">StaticRef</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">fn</span> <span class="ident">notify</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">usize</span>) {
<span class="kw">let</span> <span class="ident">me</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> _ <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">T</span>) };
<span class="ident">me</span>.<span class="ident">notify</span>(<span class="ident">id</span>);
}
<span class="kw">fn</span> <span class="ident">clone_id</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">usize</span>) <span class="op">-></span> <span class="ident">usize</span> {
<span class="kw">let</span> <span class="ident">me</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> _ <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">T</span>) };
<span class="ident">me</span>.<span class="ident">clone_id</span>(<span class="ident">id</span>)
}
<span class="kw">fn</span> <span class="ident">drop_id</span>(<span class="kw-2">&</span><span class="self">self</span>, <span class="ident">id</span>: <span class="ident">usize</span>) {
<span class="kw">let</span> <span class="ident">me</span> <span class="op">=</span> <span class="kw">unsafe</span> { <span class="kw-2">&</span><span class="kw-2">*</span>(<span class="self">self</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> _ <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> <span class="ident">T</span>) };
<span class="ident">me</span>.<span class="ident">drop_id</span>(<span class="ident">id</span>);
}
}
<span class="kw">unsafe</span> <span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Notify</span> <span class="op">+</span> <span class="lifetime">'static</span><span class="op">></span> <span class="ident">UnsafeNotify</span> <span class="kw">for</span> <span class="ident">StaticRef</span><span class="op"><</span><span class="ident">T</span><span class="op">></span> {
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">clone_raw</span>(<span class="kw-2">&</span><span class="self">self</span>) <span class="op">-></span> <span class="ident">NotifyHandle</span> {
<span class="ident">NotifyHandle</span>::<span class="ident">new</span>(<span class="self">self</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> _ <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">StaticRef</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>)
}
<span class="kw">unsafe</span> <span class="kw">fn</span> <span class="ident">drop_raw</span>(<span class="kw-2">&</span><span class="self">self</span>) {}
}
<span class="kw">impl</span><span class="op"><</span><span class="ident">T</span>: <span class="ident">Notify</span><span class="op">></span> <span class="ident">From</span><span class="op"><</span><span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">T</span><span class="op">></span> <span class="kw">for</span> <span class="ident">NotifyHandle</span> {
<span class="kw">fn</span> <span class="ident">from</span>(<span class="ident">src</span> : <span class="kw-2">&</span><span class="lifetime">'static</span> <span class="ident">T</span>) <span class="op">-></span> <span class="ident">NotifyHandle</span> {
<span class="kw">unsafe</span> { <span class="ident">NotifyHandle</span>::<span class="ident">new</span>(<span class="ident">src</span> <span class="kw">as</span> <span class="kw-2">*</span><span class="kw">const</span> _ <span class="kw">as</span> <span class="kw-2">*</span><span class="kw-2">mut</span> <span class="ident">StaticRef</span><span class="op"><</span><span class="ident">T</span><span class="op">></span>) }
}
}
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