zed/crates/gpui/src/platform.rs

mod app_menu;
mod keystroke;
#[cfg(target_os = "macos")]
mod mac;
#[cfg(any(test, feature = "test-support"))]
mod test;

use crate::{
    Action, AnyWindowHandle, AsyncWindowContext, BackgroundExecutor, Bounds, DevicePixels, Font,
    FontId, FontMetrics, FontRun, ForegroundExecutor, GlobalPixels, GlyphId, Keymap, LineLayout,
    Pixels, PlatformInput, Point, RenderGlyphParams, RenderImageParams, RenderSvgParams, Scene,
    SharedString, Size, Task, TaskLabel, WindowContext,
};
use anyhow::Result;
use async_task::Runnable;
use futures::channel::oneshot;
use parking::Unparker;
use raw_window_handle::{HasDisplayHandle, HasWindowHandle};
use seahash::SeaHasher;
use serde::{Deserialize, Serialize};
use std::borrow::Cow;
use std::hash::{Hash, Hasher};
use std::time::Duration;
use std::{
    any::Any,
    fmt::{self, Debug},
    ops::Range,
    path::{Path, PathBuf},
    rc::Rc,
    sync::Arc,
};
use uuid::Uuid;

pub use app_menu::*;
pub use keystroke::*;
#[cfg(target_os = "macos")]
pub(crate) use mac::*;
#[cfg(any(test, feature = "test-support"))]
pub(crate) use test::*;
use time::UtcOffset;
pub use util::SemanticVersion;

#[cfg(target_os = "macos")]
pub(crate) fn current_platform() -> Rc<dyn Platform> {
    Rc::new(MacPlatform::new())
}

pub(crate) trait Platform: 'static {
    fn background_executor(&self) -> BackgroundExecutor;
    fn foreground_executor(&self) -> ForegroundExecutor;
    fn text_system(&self) -> Arc<dyn PlatformTextSystem>;

    fn run(&self, on_finish_launching: Box<dyn 'static + FnOnce()>);
    fn quit(&self);
    fn restart(&self);
    fn activate(&self, ignoring_other_apps: bool);
    fn hide(&self);
    fn hide_other_apps(&self);
    fn unhide_other_apps(&self);

    fn displays(&self) -> Vec<Rc<dyn PlatformDisplay>>;
    fn display(&self, id: DisplayId) -> Option<Rc<dyn PlatformDisplay>>;
    fn active_window(&self) -> Option<AnyWindowHandle>;
    fn open_window(
        &self,
        handle: AnyWindowHandle,
        options: WindowOptions,
    ) -> Box<dyn PlatformWindow>;

    fn set_display_link_output_callback(
        &self,
        display_id: DisplayId,
        callback: Box<dyn FnMut() + Send>,
    );
    fn start_display_link(&self, display_id: DisplayId);
    fn stop_display_link(&self, display_id: DisplayId);

    fn open_url(&self, url: &str);
    fn on_open_urls(&self, callback: Box<dyn FnMut(Vec<String>)>);
    fn prompt_for_paths(
        &self,
        options: PathPromptOptions,
    ) -> oneshot::Receiver<Option<Vec<PathBuf>>>;
    fn prompt_for_new_path(&self, directory: &Path) -> oneshot::Receiver<Option<PathBuf>>;
    fn reveal_path(&self, path: &Path);

    fn on_become_active(&self, callback: Box<dyn FnMut()>);
    fn on_resign_active(&self, callback: Box<dyn FnMut()>);
    fn on_quit(&self, callback: Box<dyn FnMut()>);
    fn on_reopen(&self, callback: Box<dyn FnMut()>);
    fn on_event(&self, callback: Box<dyn FnMut(PlatformInput) -> bool>);

    fn set_menus(&self, menus: Vec<Menu>, keymap: &Keymap);
    fn on_app_menu_action(&self, callback: Box<dyn FnMut(&dyn Action)>);
    fn on_will_open_app_menu(&self, callback: Box<dyn FnMut()>);
    fn on_validate_app_menu_command(&self, callback: Box<dyn FnMut(&dyn Action) -> bool>);

    fn os_name(&self) -> &'static str;
    fn os_version(&self) -> Result<SemanticVersion>;
    fn app_version(&self) -> Result<SemanticVersion>;
    fn app_path(&self) -> Result<PathBuf>;
    fn local_timezone(&self) -> UtcOffset;
    fn double_click_interval(&self) -> Duration;
    fn path_for_auxiliary_executable(&self, name: &str) -> Result<PathBuf>;

    fn set_cursor_style(&self, style: CursorStyle);
    fn should_auto_hide_scrollbars(&self) -> bool;

    fn write_to_clipboard(&self, item: ClipboardItem);
    fn read_from_clipboard(&self) -> Option<ClipboardItem>;

    fn write_credentials(&self, url: &str, username: &str, password: &[u8]) -> Task<Result<()>>;
    fn read_credentials(&self, url: &str) -> Task<Result<Option<(String, Vec<u8>)>>>;
    fn delete_credentials(&self, url: &str) -> Task<Result<()>>;
}

/// A handle to a platform's display, e.g. a monitor or laptop screen.
pub trait PlatformDisplay: Send + Sync + Debug {
    /// Get the ID for this display
    fn id(&self) -> DisplayId;

    /// Returns a stable identifier for this display that can be persisted and used
    /// across system restarts.
    fn uuid(&self) -> Result<Uuid>;

    /// Get the bounds for this display
    fn bounds(&self) -> Bounds<GlobalPixels>;
}

/// An opaque identifier for a hardware display
#[derive(PartialEq, Eq, Hash, Copy, Clone)]
pub struct DisplayId(pub(crate) u32);

impl Debug for DisplayId {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        write!(f, "DisplayId({})", self.0)
    }
}

unsafe impl Send for DisplayId {}

pub(crate) trait PlatformWindow: HasWindowHandle + HasDisplayHandle {
    fn bounds(&self) -> WindowBounds;
    fn content_size(&self) -> Size<Pixels>;
    fn scale_factor(&self) -> f32;
    fn titlebar_height(&self) -> Pixels;
    fn appearance(&self) -> WindowAppearance;
    fn display(&self) -> Rc<dyn PlatformDisplay>;
    fn mouse_position(&self) -> Point<Pixels>;
    fn modifiers(&self) -> Modifiers;
    fn as_any_mut(&mut self) -> &mut dyn Any;
    fn set_input_handler(&mut self, input_handler: PlatformInputHandler);
    fn take_input_handler(&mut self) -> Option<PlatformInputHandler>;
    fn prompt(
        &self,
        level: PromptLevel,
        msg: &str,
        detail: Option<&str>,
        answers: &[&str],
    ) -> oneshot::Receiver<usize>;
    fn activate(&self);
    fn set_title(&mut self, title: &str);
    fn set_edited(&mut self, edited: bool);
    fn show_character_palette(&self);
    fn minimize(&self);
    fn zoom(&self);
    fn toggle_full_screen(&self);
    fn on_request_frame(&self, callback: Box<dyn FnMut()>);
    fn on_input(&self, callback: Box<dyn FnMut(PlatformInput) -> bool>);
    fn on_active_status_change(&self, callback: Box<dyn FnMut(bool)>);
    fn on_resize(&self, callback: Box<dyn FnMut(Size<Pixels>, f32)>);
    fn on_fullscreen(&self, callback: Box<dyn FnMut(bool)>);
    fn on_moved(&self, callback: Box<dyn FnMut()>);
    fn on_should_close(&self, callback: Box<dyn FnMut() -> bool>);
    fn on_close(&self, callback: Box<dyn FnOnce()>);
    fn on_appearance_changed(&self, callback: Box<dyn FnMut()>);
    fn is_topmost_for_position(&self, position: Point<Pixels>) -> bool;
    fn invalidate(&self);
    fn draw(&self, scene: &Scene);

    fn sprite_atlas(&self) -> Arc<dyn PlatformAtlas>;

    #[cfg(any(test, feature = "test-support"))]
    fn as_test(&mut self) -> Option<&mut TestWindow> {
        None
    }
}

/// This type is public so that our test macro can generate and use it, but it should not
/// be considered part of our public API.
#[doc(hidden)]
pub trait PlatformDispatcher: Send + Sync {
    fn is_main_thread(&self) -> bool;
    fn dispatch(&self, runnable: Runnable, label: Option<TaskLabel>);
    fn dispatch_on_main_thread(&self, runnable: Runnable);
    fn dispatch_after(&self, duration: Duration, runnable: Runnable);
    fn tick(&self, background_only: bool) -> bool;
    fn park(&self);
    fn unparker(&self) -> Unparker;

    #[cfg(any(test, feature = "test-support"))]
    fn as_test(&self) -> Option<&TestDispatcher> {
        None
    }
}

pub(crate) trait PlatformTextSystem: Send + Sync {
    fn add_fonts(&self, fonts: Vec<Cow<'static, [u8]>>) -> Result<()>;
    fn all_font_names(&self) -> Vec<String>;
    fn all_font_families(&self) -> Vec<String>;
    fn font_id(&self, descriptor: &Font) -> Result<FontId>;
    fn font_metrics(&self, font_id: FontId) -> FontMetrics;
    fn typographic_bounds(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Bounds<f32>>;
    fn advance(&self, font_id: FontId, glyph_id: GlyphId) -> Result<Size<f32>>;
    fn glyph_for_char(&self, font_id: FontId, ch: char) -> Option<GlyphId>;
    fn glyph_raster_bounds(&self, params: &RenderGlyphParams) -> Result<Bounds<DevicePixels>>;
    fn rasterize_glyph(
        &self,
        params: &RenderGlyphParams,
        raster_bounds: Bounds<DevicePixels>,
    ) -> Result<(Size<DevicePixels>, Vec<u8>)>;
    fn layout_line(&self, text: &str, font_size: Pixels, runs: &[FontRun]) -> LineLayout;
    fn wrap_line(
        &self,
        text: &str,
        font_id: FontId,
        font_size: Pixels,
        width: Pixels,
    ) -> Vec<usize>;
}

/// Basic metadata about the current application and operating system.
#[derive(Clone, Debug)]
pub struct AppMetadata {
    /// The name of the current operating system
    pub os_name: &'static str,

    /// The operating system's version
    pub os_version: Option<SemanticVersion>,

    /// The current version of the application
    pub app_version: Option<SemanticVersion>,
}

#[derive(PartialEq, Eq, Hash, Clone)]
pub(crate) enum AtlasKey {
    Glyph(RenderGlyphParams),
    Svg(RenderSvgParams),
    Image(RenderImageParams),
}

impl AtlasKey {
    pub(crate) fn texture_kind(&self) -> AtlasTextureKind {
        match self {
            AtlasKey::Glyph(params) => {
                if params.is_emoji {
                    AtlasTextureKind::Polychrome
                } else {
                    AtlasTextureKind::Monochrome
                }
            }
            AtlasKey::Svg(_) => AtlasTextureKind::Monochrome,
            AtlasKey::Image(_) => AtlasTextureKind::Polychrome,
        }
    }
}

impl From<RenderGlyphParams> for AtlasKey {
    fn from(params: RenderGlyphParams) -> Self {
        Self::Glyph(params)
    }
}

impl From<RenderSvgParams> for AtlasKey {
    fn from(params: RenderSvgParams) -> Self {
        Self::Svg(params)
    }
}

impl From<RenderImageParams> for AtlasKey {
    fn from(params: RenderImageParams) -> Self {
        Self::Image(params)
    }
}

pub(crate) trait PlatformAtlas: Send + Sync {
    fn get_or_insert_with<'a>(
        &self,
        key: &AtlasKey,
        build: &mut dyn FnMut() -> Result<(Size<DevicePixels>, Cow<'a, [u8]>)>,
    ) -> Result<AtlasTile>;
}

#[derive(Clone, Debug, PartialEq, Eq)]
#[repr(C)]
pub(crate) struct AtlasTile {
    pub(crate) texture_id: AtlasTextureId,
    pub(crate) tile_id: TileId,
    pub(crate) bounds: Bounds<DevicePixels>,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
#[repr(C)]
pub(crate) struct AtlasTextureId {
    // We use u32 instead of usize for Metal Shader Language compatibility
    pub(crate) index: u32,
    pub(crate) kind: AtlasTextureKind,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
#[repr(C)]
pub(crate) enum AtlasTextureKind {
    Monochrome = 0,
    Polychrome = 1,
    Path = 2,
}

#[derive(Clone, Copy, Debug, PartialEq, Eq, PartialOrd, Ord)]
#[repr(C)]
pub(crate) struct TileId(pub(crate) u32);

impl From<etagere::AllocId> for TileId {
    fn from(id: etagere::AllocId) -> Self {
        Self(id.serialize())
    }
}

impl From<TileId> for etagere::AllocId {
    fn from(id: TileId) -> Self {
        Self::deserialize(id.0)
    }
}

pub(crate) struct PlatformInputHandler {
    cx: AsyncWindowContext,
    handler: Box<dyn InputHandler>,
}

impl PlatformInputHandler {
    pub fn new(cx: AsyncWindowContext, handler: Box<dyn InputHandler>) -> Self {
        Self { cx, handler }
    }

    fn selected_text_range(&mut self) -> Option<Range<usize>> {
        self.cx
            .update(|cx| self.handler.selected_text_range(cx))
            .ok()
            .flatten()
    }

    fn marked_text_range(&mut self) -> Option<Range<usize>> {
        self.cx
            .update(|cx| self.handler.marked_text_range(cx))
            .ok()
            .flatten()
    }

    fn text_for_range(&mut self, range_utf16: Range<usize>) -> Option<String> {
        self.cx
            .update(|cx| self.handler.text_for_range(range_utf16, cx))
            .ok()
            .flatten()
    }

    fn replace_text_in_range(&mut self, replacement_range: Option<Range<usize>>, text: &str) {
        self.cx
            .update(|cx| {
                self.handler
                    .replace_text_in_range(replacement_range, text, cx);
            })
            .ok();
    }

    fn replace_and_mark_text_in_range(
        &mut self,
        range_utf16: Option<Range<usize>>,
        new_text: &str,
        new_selected_range: Option<Range<usize>>,
    ) {
        self.cx
            .update(|cx| {
                self.handler.replace_and_mark_text_in_range(
                    range_utf16,
                    new_text,
                    new_selected_range,
                    cx,
                )
            })
            .ok();
    }

    fn unmark_text(&mut self) {
        self.cx.update(|cx| self.handler.unmark_text(cx)).ok();
    }

    fn bounds_for_range(&mut self, range_utf16: Range<usize>) -> Option<Bounds<Pixels>> {
        self.cx
            .update(|cx| self.handler.bounds_for_range(range_utf16, cx))
            .ok()
            .flatten()
    }

    pub(crate) fn flush_pending_input(&mut self, input: &str, cx: &mut WindowContext) {
        let Some(range) = self.handler.selected_text_range(cx) else {
            return;
        };
        self.handler.replace_text_in_range(Some(range), input, cx);
    }
}

/// Zed's interface for handling text input from the platform's IME system
/// This is currently a 1:1 exposure of the NSTextInputClient API:
///
/// <https://developer.apple.com/documentation/appkit/nstextinputclient>
pub trait InputHandler: 'static {
    /// Get the range of the user's currently selected text, if any
    /// Corresponds to [selectedRange()](https://developer.apple.com/documentation/appkit/nstextinputclient/1438242-selectedrange)
    ///
    /// Return value is in terms of UTF-16 characters, from 0 to the length of the document
    fn selected_text_range(&mut self, cx: &mut WindowContext) -> Option<Range<usize>>;

    /// Get the range of the currently marked text, if any
    /// Corresponds to [markedRange()](https://developer.apple.com/documentation/appkit/nstextinputclient/1438250-markedrange)
    ///
    /// Return value is in terms of UTF-16 characters, from 0 to the length of the document
    fn marked_text_range(&mut self, cx: &mut WindowContext) -> Option<Range<usize>>;

    /// Get the text for the given document range in UTF-16 characters
    /// Corresponds to [attributedSubstring(forProposedRange: actualRange:)](https://developer.apple.com/documentation/appkit/nstextinputclient/1438238-attributedsubstring)
    ///
    /// range_utf16 is in terms of UTF-16 characters
    fn text_for_range(
        &mut self,
        range_utf16: Range<usize>,
        cx: &mut WindowContext,
    ) -> Option<String>;

    /// Replace the text in the given document range with the given text
    /// Corresponds to [insertText(_:replacementRange:)](https://developer.apple.com/documentation/appkit/nstextinputclient/1438258-inserttext)
    ///
    /// replacement_range is in terms of UTF-16 characters
    fn replace_text_in_range(
        &mut self,
        replacement_range: Option<Range<usize>>,
        text: &str,
        cx: &mut WindowContext,
    );

    /// Replace the text in the given document range with the given text,
    /// and mark the given text as part of of an IME 'composing' state
    /// Corresponds to [setMarkedText(_:selectedRange:replacementRange:)](https://developer.apple.com/documentation/appkit/nstextinputclient/1438246-setmarkedtext)
    ///
    /// range_utf16 is in terms of UTF-16 characters
    /// new_selected_range is in terms of UTF-16 characters
    fn replace_and_mark_text_in_range(
        &mut self,
        range_utf16: Option<Range<usize>>,
        new_text: &str,
        new_selected_range: Option<Range<usize>>,
        cx: &mut WindowContext,
    );

    /// Remove the IME 'composing' state from the document
    /// Corresponds to [unmarkText()](https://developer.apple.com/documentation/appkit/nstextinputclient/1438239-unmarktext)
    fn unmark_text(&mut self, cx: &mut WindowContext);

    /// Get the bounds of the given document range in screen coordinates
    /// Corresponds to [firstRect(forCharacterRange:actualRange:)](https://developer.apple.com/documentation/appkit/nstextinputclient/1438240-firstrect)
    ///
    /// This is used for positioning the IME candidate window
    fn bounds_for_range(
        &mut self,
        range_utf16: Range<usize>,
        cx: &mut WindowContext,
    ) -> Option<Bounds<Pixels>>;
}

/// The variables that can be configured when creating a new window
#[derive(Debug)]
pub struct WindowOptions {
    /// The initial bounds of the window
    pub bounds: WindowBounds,

    /// The titlebar configuration of the window
    pub titlebar: Option<TitlebarOptions>,

    /// Whether the window should be centered on the screen
    pub center: bool,

    /// Whether the window should be focused when created
    pub focus: bool,

    /// Whether the window should be shown when created
    pub show: bool,

    /// The kind of window to create
    pub kind: WindowKind,

    /// Whether the window should be movable by the user
    pub is_movable: bool,

    /// The display to create the window on
    pub display_id: Option<DisplayId>,
}

impl Default for WindowOptions {
    fn default() -> Self {
        Self {
            bounds: WindowBounds::default(),
            titlebar: Some(TitlebarOptions {
                title: Default::default(),
                appears_transparent: Default::default(),
                traffic_light_position: Default::default(),
            }),
            center: false,
            focus: true,
            show: true,
            kind: WindowKind::Normal,
            is_movable: true,
            display_id: None,
        }
    }
}

/// The options that can be configured for a window's titlebar
#[derive(Debug, Default)]
pub struct TitlebarOptions {
    /// The initial title of the window
    pub title: Option<SharedString>,

    /// Whether the titlebar should appear transparent
    pub appears_transparent: bool,

    /// The position of the macOS traffic light buttons
    pub traffic_light_position: Option<Point<Pixels>>,
}

/// The kind of window to create
#[derive(Copy, Clone, Debug, PartialEq, Eq)]
pub enum WindowKind {
    /// A normal application window
    Normal,

    /// A window that appears above all other windows, usually used for alerts or popups
    /// use sparingly!
    PopUp,
}

/// Which bounds algorithm to use for the initial size a window
#[derive(Copy, Clone, Debug, PartialEq, Default)]
pub enum WindowBounds {
    /// The window should be full screen, on macOS this corresponds to the full screen feature
    Fullscreen,

    /// Make the window as large as the current display's size.
    #[default]
    Maximized,

    /// Set the window to the given size in pixels
    Fixed(Bounds<GlobalPixels>),
}

/// The appearance of the window, as defined by the operating system
/// On macOS, this corresponds to named [NSAppearance](https://developer.apple.com/documentation/appkit/nsappearance)
/// values
#[derive(Copy, Clone, Debug)]
pub enum WindowAppearance {
    /// A light appearance
    ///
    /// on macOS, this corresponds to the `aqua` appearance
    Light,

    /// A light appearance with vibrant colors
    ///
    /// on macOS, this corresponds to the `NSAppearanceNameVibrantLight` appearance
    VibrantLight,

    /// A dark appearance
    ///
    /// on macOS, this corresponds to the `darkAqua` appearance
    Dark,

    /// A dark appearance with vibrant colors
    ///
    /// on macOS, this corresponds to the `NSAppearanceNameVibrantDark` appearance
    VibrantDark,
}

impl Default for WindowAppearance {
    fn default() -> Self {
        Self::Light
    }
}

/// The options that can be configured for a file dialog prompt
#[derive(Copy, Clone, Debug)]
pub struct PathPromptOptions {
    /// Should the prompt allow files to be selected?
    pub files: bool,
    /// Should the prompt allow directories to be selected?
    pub directories: bool,
    /// Should the prompt allow multiple files to be selected?
    pub multiple: bool,
}

/// What kind of prompt styling to show
#[derive(Copy, Clone, Debug)]
pub enum PromptLevel {
    /// A prompt that is shown when the user should be notified of something
    Info,

    /// A prompt that is shown when the user needs to be warned of a potential problem
    Warning,

    /// A prompt that is shown when a critical problem has occurred
    Critical,
}

/// The style of the cursor (pointer)
#[derive(Copy, Clone, Debug)]
pub enum CursorStyle {
    /// The default cursor
    Arrow,

    /// A text input cursor
    /// corresponds to the CSS cursor value `text`
    IBeam,

    /// A crosshair cursor
    /// corresponds to the CSS cursor value `crosshair`
    Crosshair,

    /// A closed hand cursor
    /// corresponds to the CSS cursor value `grabbing`
    ClosedHand,

    /// An open hand cursor
    /// corresponds to the CSS cursor value `grab`
    OpenHand,

    /// A pointing hand cursor
    /// corresponds to the CSS cursor value `pointer`
    PointingHand,

    /// A resize left cursor
    /// corresponds to the CSS cursor value `w-resize`
    ResizeLeft,

    /// A resize right cursor
    /// corresponds to the CSS cursor value `e-resize`
    ResizeRight,

    /// A resize cursor to the left and right
    /// corresponds to the CSS cursor value `col-resize`
    ResizeLeftRight,

    /// A resize up cursor
    /// corresponds to the CSS cursor value `n-resize`
    ResizeUp,

    /// A resize down cursor
    /// corresponds to the CSS cursor value `s-resize`
    ResizeDown,

    /// A resize cursor directing up and down
    /// corresponds to the CSS cursor value `row-resize`
    ResizeUpDown,

    /// A cursor indicating that something will disappear if moved here
    /// Does not correspond to a CSS cursor value
    DisappearingItem,

    /// A text input cursor for vertical layout
    /// corresponds to the CSS cursor value `vertical-text`
    IBeamCursorForVerticalLayout,

    /// A cursor indicating that the operation is not allowed
    /// corresponds to the CSS cursor value `not-allowed`
    OperationNotAllowed,

    /// A cursor indicating that the operation will result in a link
    /// corresponds to the CSS cursor value `alias`
    DragLink,

    /// A cursor indicating that the operation will result in a copy
    /// corresponds to the CSS cursor value `copy`
    DragCopy,

    /// A cursor indicating that the operation will result in a context menu
    /// corresponds to the CSS cursor value `context-menu`
    ContextualMenu,
}

impl Default for CursorStyle {
    fn default() -> Self {
        Self::Arrow
    }
}

/// A clipboard item that should be copied to the clipboard
#[derive(Clone, Debug, Eq, PartialEq)]
pub struct ClipboardItem {
    pub(crate) text: String,
    pub(crate) metadata: Option<String>,
}

impl ClipboardItem {
    /// Create a new clipboard item with the given text
    pub fn new(text: String) -> Self {
        Self {
            text,
            metadata: None,
        }
    }

    /// Create a new clipboard item with the given text and metadata
    pub fn with_metadata<T: Serialize>(mut self, metadata: T) -> Self {
        self.metadata = Some(serde_json::to_string(&metadata).unwrap());
        self
    }

    /// Get the text of the clipboard item
    pub fn text(&self) -> &String {
        &self.text
    }

    /// Get the metadata of the clipboard item
    pub fn metadata<T>(&self) -> Option<T>
    where
        T: for<'a> Deserialize<'a>,
    {
        self.metadata
            .as_ref()
            .and_then(|m| serde_json::from_str(m).ok())
    }

    pub(crate) fn text_hash(text: &str) -> u64 {
        let mut hasher = SeaHasher::new();
        text.hash(&mut hasher);
        hasher.finish()
    }
}