Refactor for testing.

src/library.rs

@@ -7,8 +7,10 @@ use std::sync::Arc;
 
 use google_photoslibrary1 as photos;
 use image::imageops::FilterType;
+use image::DynamicImage;
 use image::GenericImageView;
 use image::ImageFormat;
+use image::ImageResult;
 use log::error;
 use log::info;
 use log::warn;
@@ -28,6 +30,37 @@ pub struct Library {
     cache_db: Arc<DB>,
 }
 
+pub fn load_image<P>(path: P) -> ImageResult<DynamicImage>
+where
+    P: AsRef<Path>,
+{
+    image::io::Reader::open(&path)?
+        .with_guessed_format()?
+        .decode()
+}
+
+pub fn resize(
+    img: &DynamicImage,
+    dimensions: (Option<u32>, Option<u32>),
+    filter: FilterType,
+) -> DynamicImage {
+    let (w, h) = dimensions;
+    let (orig_w, orig_h) = img.dimensions();
+    let (w, h) = match (w, h) {
+        (Some(w), Some(h)) => (w, h),
+        (Some(w), None) => (w, orig_h * w / orig_w),
+        (None, Some(h)) => (orig_w * h / orig_h, h),
+        (None, None) => (orig_w, orig_h),
+    };
+    img.resize_to_fill(w, h, filter)
+}
+
+pub fn save_to_jpeg_bytes(img: DynamicImage) -> ImageResult<Vec<u8>> {
+    let mut buf = Vec::new();
+    img.write_to(&mut buf, ImageFormat::Jpeg)?;
+    Ok(buf)
+}
+
 impl Library {
     pub fn new(root: PathBuf) -> Result<Library, Box<dyn std::error::Error>> {
         let db = DB::open_default(root.join("cache"))?;
@@ -155,7 +188,7 @@ impl Library {
     pub fn generate_thumbnail(
         &self,
         media_items_id: &str,
-        (w, h): (Option<u32>, Option<u32>),
+        dimensions: (Option<u32>, Option<u32>),
         filter: FilterType,
     ) -> Result<Vec<u8>, io::Error> {
         match self.original(&media_items_id) {
@@ -167,21 +200,11 @@ impl Library {
                 ))
             }
             Some(path) => {
-                let orig_img = image::io::Reader::open(&path)?
-                    .with_guessed_format()?
-                    .decode()
-                    .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
-                let (orig_w, orig_h) = orig_img.dimensions();
-                let (w, h) = match (w, h) {
-                    (Some(w), Some(h)) => (w, h),
-                    (Some(w), None) => (w, orig_h * w / orig_w),
-                    (None, Some(h)) => (orig_w * h / orig_h, h),
-                    (None, None) => (orig_w, orig_h),
-                };
-                let img = orig_img.resize_to_fill(w, h, filter);
-                let mut buf = Vec::new();
-                img.write_to(&mut buf, ImageFormat::Jpeg)
-                    .map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+                let orig_img =
+                    load_image(&path).map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
+                let img = resize(&orig_img, dimensions, filter);
+                let buf =
+                    save_to_jpeg_bytes(img).map_err(|e| io::Error::new(io::ErrorKind::Other, e))?;
                 Ok(buf)
             }
         }