108 lines
3.2 KiB
Rust
108 lines
3.2 KiB
Rust
use crate::window;
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/// A connection to the state of a shell.
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///
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/// A [`Widget`] can leverage a [`Shell`] to trigger changes in an application,
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/// like publishing messages or invalidating the current layout.
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///
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/// [`Widget`]: crate::Widget
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#[derive(Debug)]
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pub struct Shell<'a, Message> {
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messages: &'a mut Vec<Message>,
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redraw_request: Option<window::RedrawRequest>,
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is_layout_invalid: bool,
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are_widgets_invalid: bool,
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}
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impl<'a, Message> Shell<'a, Message> {
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/// Creates a new [`Shell`] with the provided buffer of messages.
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pub fn new(messages: &'a mut Vec<Message>) -> Self {
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Self {
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messages,
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redraw_request: None,
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is_layout_invalid: false,
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are_widgets_invalid: false,
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}
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}
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/// Returns true if the [`Shell`] contains no published messages
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pub fn is_empty(&self) -> bool {
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self.messages.is_empty()
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}
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/// Publish the given `Message` for an application to process it.
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pub fn publish(&mut self, message: Message) {
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self.messages.push(message);
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}
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/// Requests a new frame to be drawn.
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pub fn request_redraw(&mut self, request: window::RedrawRequest) {
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match self.redraw_request {
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None => {
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self.redraw_request = Some(request);
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}
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Some(current) if request < current => {
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self.redraw_request = Some(request);
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}
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_ => {}
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}
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}
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/// Returns the request a redraw should happen, if any.
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pub fn redraw_request(&self) -> Option<window::RedrawRequest> {
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self.redraw_request
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}
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/// Returns whether the current layout is invalid or not.
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pub fn is_layout_invalid(&self) -> bool {
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self.is_layout_invalid
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}
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/// Invalidates the current application layout.
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///
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/// The shell will relayout the application widgets.
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pub fn invalidate_layout(&mut self) {
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self.is_layout_invalid = true;
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}
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/// Triggers the given function if the layout is invalid, cleaning it in the
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/// process.
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pub fn revalidate_layout(&mut self, f: impl FnOnce()) {
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if self.is_layout_invalid {
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self.is_layout_invalid = false;
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f()
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}
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}
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/// Returns whether the widgets of the current application have been
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/// invalidated.
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pub fn are_widgets_invalid(&self) -> bool {
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self.are_widgets_invalid
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}
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/// Invalidates the current application widgets.
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///
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/// The shell will rebuild and relayout the widget tree.
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pub fn invalidate_widgets(&mut self) {
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self.are_widgets_invalid = true;
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}
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/// Merges the current [`Shell`] with another one by applying the given
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/// function to the messages of the latter.
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///
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/// This method is useful for composition.
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pub fn merge<B>(&mut self, other: Shell<'_, B>, f: impl Fn(B) -> Message) {
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self.messages.extend(other.messages.drain(..).map(f));
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if let Some(at) = other.redraw_request {
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self.request_redraw(at);
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}
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self.is_layout_invalid =
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self.is_layout_invalid || other.is_layout_invalid;
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self.are_widgets_invalid =
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self.are_widgets_invalid || other.are_widgets_invalid;
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}
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}
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