chore: refactor ahead of supporting more conversion types

src/formats/cbz.rs

@@ -0,0 +1,53 @@
+use std::ffi::OsStr;
+use std::fs::File;
+use std::io::Read;
+use std::path::Path;
+
+use anyhow::Result;
+use rayon::prelude::*;
+use zip::ZipArchive;
+
+use crate::model::{Document, ImagePage};
+
+use super::FormatReader;
+
+pub struct CbzReader;
+
+impl FormatReader for CbzReader {
+    fn read(&self, input: &Path) -> Result<Document> {
+        let mut zip = ZipArchive::new(File::open(input)?)?;
+        let mut files: Vec<(String, Vec<u8>)> = Vec::new();
+        for i in 0..zip.len() {
+            let mut file = zip.by_index(i)?;
+            let mut image_data = Vec::new();
+            let name = file
+                .enclosed_name()
+                .expect("Failed to read file name")
+                .to_owned();
+            if name.extension() == Some(OsStr::new("jpg")) {
+                file.read_to_end(&mut image_data)?;
+                files.push((
+                    name.file_name()
+                        .expect("Failed to read file name")
+                        .to_string_lossy()
+                        .to_string(),
+                    image_data,
+                ));
+            }
+        }
+
+        let mut pages: Vec<ImagePage> = Vec::new();
+        files
+            .par_iter()
+            .map(|(name, data)| ImagePage {
+                name: name.clone(),
+                image: image::load_from_memory(data).expect("Failed to decode image"),
+                jpeg_dct: Some(data.clone()),
+            })
+            .collect_into_vec(&mut pages);
+
+        pages.par_sort_by_key(|p| p.name.clone());
+
+        Ok(Document::new(pages))
+    }
+}