Remove image store

1 files changed, 108 insertions, 182 deletions

diff --git a/src/image.rs b/src/image.rs
index 8ef404fe..c2631477 100644
--- a/src/image.rs
+++ b/src/image.rs
@@ -1,213 +1,139 @@
 //! Image handling.
 
-use std::collections::{hash_map::Entry, HashMap};
-use std::ffi::OsStr;
-use std::fmt::{self, Debug, Formatter};
 use std::io;
-use std::path::Path;
-use std::sync::Arc;
 
-use image::io::Reader as ImageReader;
-use image::{DynamicImage, ImageFormat};
-
-use crate::diag::{failed_to_load, StrResult};
-use crate::loading::{FileHash, Loader};
-
-/// A unique identifier for a loaded image.
-#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
-pub struct ImageId(u32);
-
-impl ImageId {
-    /// Create an image id from the raw underlying value.
-    ///
-    /// This should only be called with values returned by
-    /// [`into_raw`](Self::into_raw).
-    pub const fn from_raw(v: u32) -> Self {
-        Self(v)
-    }
-
-    /// Convert into the raw underlying value.
-    pub const fn into_raw(self) -> u32 {
-        self.0
-    }
+use crate::loading::Buffer;
+
+/// A raster or vector image.
+///
+/// Values of this type are cheap to clone and hash.
+#[derive(Debug, Clone, Eq, PartialEq, Hash)]
+pub struct Image {
+    /// The raw, undecoded image data.
+    data: Buffer,
+    /// The format of the encoded `buffer`.
+    format: ImageFormat,
+    /// The width in pixels.
+    width: u32,
+    /// The height in pixels.
+    height: u32,
 }
 
-/// Storage for loaded and decoded images.
-pub struct ImageStore {
-    loader: Arc<dyn Loader>,
-    files: HashMap<FileHash, ImageId>,
-    images: Vec<Image>,
+/// A decoded image.
+pub enum DecodedImage {
+    /// A pixel raster format, like PNG or JPEG.
+    Raster(image::DynamicImage),
+    /// An SVG vector graphic.
+    Svg(usvg::Tree),
 }
 
-impl ImageStore {
-    /// Create a new, empty image store.
-    pub fn new(loader: Arc<dyn Loader>) -> Self {
-        Self {
-            loader,
-            files: HashMap::new(),
-            images: vec![],
-        }
-    }
+/// A raster or vector image format.
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+pub enum ImageFormat {
+    /// Raster format for illustrations and transparent graphics.
+    Png,
+    /// Lossy raster format suitable for photos.
+    Jpg,
+    /// Raster format that is typically used for short animated clips.
+    Gif,
+    /// The vector graphics format of the web.
+    Svg,
+}
 
-    /// Get a reference to a loaded image.
+impl Image {
+    /// Create an image from a raw buffer and a file extension.
     ///
-    /// This panics if no image with this `id` was loaded. This function should
-    /// only be called with ids returned by this store's [`load()`](Self::load)
-    /// method.
-    #[track_caller]
-    pub fn get(&self, id: ImageId) -> &Image {
-        &self.images[id.0 as usize]
-    }
+    /// The file extension is used to determine the format.
+    pub fn new(data: Buffer, ext: &str) -> io::Result<Self> {
+        let format = match ext {
+            "svg" | "svgz" => ImageFormat::Svg,
+            "png" => ImageFormat::Png,
+            "jpg" | "jpeg" => ImageFormat::Jpg,
+            "gif" => ImageFormat::Gif,
+            _ => {
+                return Err(io::Error::new(
+                    io::ErrorKind::InvalidData,
+                    "unknown image format",
+                ));
+            }
+        };
 
-    /// Load and decode an image file from a path relative to the compilation
-    /// environment's root.
-    pub fn load(&mut self, path: &Path) -> StrResult<ImageId> {
-        let mut try_load = || -> io::Result<ImageId> {
-            let hash = self.loader.resolve(path)?;
-            Ok(*match self.files.entry(hash) {
-                Entry::Occupied(entry) => entry.into_mut(),
-                Entry::Vacant(entry) => {
-                    let buffer = self.loader.load(path)?;
-                    let ext =
-                        path.extension().and_then(OsStr::to_str).unwrap_or_default();
-                    let image = Image::parse(&buffer, ext)?;
-                    let id = ImageId(self.images.len() as u32);
-                    self.images.push(image);
-                    entry.insert(id)
-                }
-            })
+        let (width, height) = match format {
+            ImageFormat::Svg => {
+                let opts = usvg::Options::default();
+                let tree =
+                    usvg::Tree::from_data(&data, &opts.to_ref()).map_err(invalid)?;
+
+                let size = tree.svg_node().size;
+                let width = size.width().ceil() as u32;
+                let height = size.height().ceil() as u32;
+                (width, height)
+            }
+            _ => {
+                let cursor = io::Cursor::new(&data);
+                let format = convert_format(format);
+                let reader = image::io::Reader::with_format(cursor, format);
+                reader.into_dimensions().map_err(invalid)?
+            }
         };
 
-        try_load().map_err(|err| failed_to_load("image", path, err))
+        Ok(Self { data, format, width, height })
     }
-}
 
-/// A loaded image.
-#[derive(Debug)]
-pub enum Image {
-    /// A pixel raster format, like PNG or JPEG.
-    Raster(RasterImage),
-    /// An SVG vector graphic.
-    Svg(Svg),
-}
+    /// The raw image data.
+    pub fn data(&self) -> &Buffer {
+        &self.data
+    }
 
-impl Image {
-    /// Parse an image from raw data. The file extension is used as a hint for
-    /// which error message describes the problem best.
-    pub fn parse(data: &[u8], ext: &str) -> io::Result<Self> {
-        match Svg::parse(data) {
-            Ok(svg) => return Ok(Self::Svg(svg)),
-            Err(err) if matches!(ext, "svg" | "svgz") => return Err(err),
-            Err(_) => {}
-        }
-
-        match RasterImage::parse(data) {
-            Ok(raster) => return Ok(Self::Raster(raster)),
-            Err(err) if matches!(ext, "png" | "jpg" | "jpeg" | "gif") => return Err(err),
-            Err(_) => {}
-        }
-
-        Err(io::Error::new(
-            io::ErrorKind::InvalidData,
-            "unknown image format",
-        ))
+    /// The format of the image.
+    pub fn format(&self) -> ImageFormat {
+        self.format
     }
 
     /// The width of the image in pixels.
     pub fn width(&self) -> u32 {
-        match self {
-            Self::Raster(image) => image.width(),
-            Self::Svg(image) => image.width(),
-        }
+        self.width
     }
 
     /// The height of the image in pixels.
     pub fn height(&self) -> u32 {
-        match self {
-            Self::Raster(image) => image.height(),
-            Self::Svg(image) => image.height(),
-        }
+        self.height
+    }
+
+    /// Decode the image.
+    pub fn decode(&self) -> io::Result<DecodedImage> {
+        Ok(match self.format {
+            ImageFormat::Svg => {
+                let opts = usvg::Options::default();
+                let tree =
+                    usvg::Tree::from_data(&self.data, &opts.to_ref()).map_err(invalid)?;
+                DecodedImage::Svg(tree)
+            }
+            _ => {
+                let cursor = io::Cursor::new(&self.data);
+                let format = convert_format(self.format);
+                let reader = image::io::Reader::with_format(cursor, format);
+                let dynamic = reader.decode().map_err(invalid)?;
+                DecodedImage::Raster(dynamic)
+            }
+        })
     }
 }
 
-/// A raster image, supported through the image crate.
-pub struct RasterImage {
-    /// The original format the image was encoded in.
-    pub format: ImageFormat,
-    /// The decoded image.
-    pub buf: DynamicImage,
-}
-
-impl RasterImage {
-    /// Parse an image from raw data in a supported format (PNG, JPEG or GIF).
-    ///
-    /// The image format is determined automatically.
-    pub fn parse(data: &[u8]) -> io::Result<Self> {
-        let cursor = io::Cursor::new(data);
-        let reader = ImageReader::new(cursor).with_guessed_format()?;
-        let format = reader
-            .format()
-            .ok_or_else(|| io::Error::from(io::ErrorKind::InvalidData))?;
-
-        let buf = reader
-            .decode()
-            .map_err(|err| io::Error::new(io::ErrorKind::InvalidData, err))?;
-
-        Ok(Self { format, buf })
-    }
-
-    /// The width of the image.
-    pub fn width(&self) -> u32 {
-        self.buf.width()
-    }
-
-    /// The height of the image.
-    pub fn height(&self) -> u32 {
-        self.buf.height()
-    }
-}
-
-impl Debug for RasterImage {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        f.debug_struct("Image")
-            .field("format", &self.format)
-            .field("color", &self.buf.color())
-            .field("width", &self.width())
-            .field("height", &self.height())
-            .finish()
+/// Convert a raster image format to the image crate's format.
+fn convert_format(format: ImageFormat) -> image::ImageFormat {
+    match format {
+        ImageFormat::Png => image::ImageFormat::Png,
+        ImageFormat::Jpg => image::ImageFormat::Jpeg,
+        ImageFormat::Gif => image::ImageFormat::Gif,
+        ImageFormat::Svg => panic!("must be a raster format"),
     }
 }
 
-/// An SVG image, supported through the usvg crate.
-pub struct Svg(pub usvg::Tree);
-
-impl Svg {
-    /// Parse an SVG file from a data buffer. This also handles `.svgz`
-    /// compressed files.
-    pub fn parse(data: &[u8]) -> io::Result<Self> {
-        let usvg_opts = usvg::Options::default();
-        usvg::Tree::from_data(data, &usvg_opts.to_ref())
-            .map(Self)
-            .map_err(|err| io::Error::new(io::ErrorKind::InvalidData, err))
-    }
-
-    /// The width of the image in rounded-up nominal SVG pixels.
-    pub fn width(&self) -> u32 {
-        self.0.svg_node().size.width().ceil() as u32
-    }
-
-    /// The height of the image in rounded-up nominal SVG pixels.
-    pub fn height(&self) -> u32 {
-        self.0.svg_node().size.height().ceil() as u32
-    }
-}
-
-impl Debug for Svg {
-    fn fmt(&self, f: &mut Formatter) -> fmt::Result {
-        f.debug_struct("Svg")
-            .field("width", &self.0.svg_node().size.width())
-            .field("height", &self.0.svg_node().size.height())
-            .field("viewBox", &self.0.svg_node().view_box)
-            .finish()
-    }
+/// Turn any error into an I/O error.
+fn invalid<E>(error: E) -> io::Error
+where
+    E: std::error::Error + Send + Sync + 'static,
+{
+    io::Error::new(io::ErrorKind::InvalidData, error)
 }