Checkpoint

crates/gpui/src/image_cache.rs

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+use std::sync::Arc;
+
+use crate::ImageData;
+use collections::HashMap;
+use futures::{
+    future::{BoxFuture, Shared},
+    AsyncReadExt, FutureExt,
+};
+use image::ImageError;
+use parking_lot::Mutex;
+use thiserror::Error;
+use util::{
+    arc_cow::ArcCow,
+    defer,
+    http::{self, HttpClient},
+};
+
+#[derive(Debug, Error, Clone)]
+pub enum Error {
+    #[error("http error: {0}")]
+    Client(#[from] http::Error),
+    #[error("IO error: {0}")]
+    Io(Arc<std::io::Error>),
+    #[error("unexpected http status: {status}, body: {body}")]
+    BadStatus {
+        status: http::StatusCode,
+        body: String,
+    },
+    #[error("image error: {0}")]
+    Image(Arc<ImageError>),
+}
+
+impl From<std::io::Error> for Error {
+    fn from(error: std::io::Error) -> Self {
+        Error::Io(Arc::new(error))
+    }
+}
+
+impl From<ImageError> for Error {
+    fn from(error: ImageError) -> Self {
+        Error::Image(Arc::new(error))
+    }
+}
+
+pub struct ImageCache {
+    client: Arc<dyn HttpClient>,
+    images: Arc<
+        Mutex<
+            HashMap<
+                ArcCow<'static, str>,
+                Shared<BoxFuture<'static, Result<Arc<ImageData>, Error>>>,
+            >,
+        >,
+    >,
+}
+
+impl ImageCache {
+    pub fn new(client: Arc<dyn HttpClient>) -> Self {
+        ImageCache {
+            client,
+            images: Default::default(),
+        }
+    }
+
+    pub fn get(
+        &self,
+        uri: ArcCow<'static, str>,
+    ) -> Shared<BoxFuture<'static, Result<Arc<ImageData>, Error>>> {
+        match self.images.lock().get(uri.as_ref()) {
+            Some(future) => future.clone(),
+            None => {
+                let client = self.client.clone();
+                let images = self.images.clone();
+                let future = {
+                    let uri = uri.clone();
+                    async move {
+                        // If we error, remove the cached future. Otherwise we cancel before returning.
+                        let remove_cached_future = defer({
+                            let uri = uri.clone();
+                            move || {
+                                images.lock().remove(uri.as_ref());
+                            }
+                        });
+
+                        let mut response = client.get(uri.as_ref(), ().into(), true).await?;
+                        let mut body = Vec::new();
+                        response.body_mut().read_to_end(&mut body).await?;
+
+                        if !response.status().is_success() {
+                            return Err(Error::BadStatus {
+                                status: response.status(),
+                                body: String::from_utf8_lossy(&body).into_owned(),
+                            });
+                        }
+
+                        let format = image::guess_format(&body)?;
+                        let image =
+                            image::load_from_memory_with_format(&body, format)?.into_bgra8();
+
+                        remove_cached_future.cancel();
+                        Ok(ImageData::new(image))
+                    }
+                }
+                .boxed()
+                .shared();
+                self.images.lock().insert(uri.clone(), future.clone());
+                future
+            }
+        }
+    }
+}