Create a proper ThumbnailError type and reduce use of unwrap()
- ID
4d27c2c- date
2025-09-08 12:43:59+00:00- author
Alex Chan <alex@alexwlchan.net>- parent
c6ba7df- message
Create a proper `ThumbnailError` type and reduce use of `unwrap()`- changed files
5 files, 94 additions, 33 deletions
Changed files
src/create_parent_directory.rs (1216) → src/create_parent_directory.rs (1212)
diff --git a/src/create_parent_directory.rs b/src/create_parent_directory.rs
index 8be75e0..771cefe 100644
--- a/src/create_parent_directory.rs
+++ b/src/create_parent_directory.rs
@@ -1,5 +1,5 @@
use std::fs;
-use std::io::Result;
+use std::io;
use std::path::PathBuf;
/// Create the parent directory of a given path.
@@ -9,7 +9,7 @@ use std::path::PathBuf;
/// create_parent_directory("path/to/images/index.html")
/// ~> creates "path/to/images/"
///
-pub fn create_parent_directory(path: &PathBuf) -> Result<()> {
+pub fn create_parent_directory(path: &PathBuf) -> io::Result<()> {
// Quoting from the Rust docs for PathBuf.parent() [1]:
//
// Returns None if the path terminates in a root or prefix,
src/create_thumbnail.rs (7868) → src/create_thumbnail.rs (7988)
diff --git a/src/create_thumbnail.rs b/src/create_thumbnail.rs
index 6650362..4ca09e6 100644
--- a/src/create_thumbnail.rs
+++ b/src/create_thumbnail.rs
@@ -1,4 +1,3 @@
-use std::io;
use std::path::PathBuf;
use std::process::Command;
use std::str;
@@ -6,6 +5,7 @@ use std::str;
use image::imageops::FilterType;
use crate::create_parent_directory::create_parent_directory;
+use crate::errors::ThumbnailError;
use crate::get_thumbnail_dimensions::{get_thumbnail_dimensions, TargetDimension};
use crate::is_animated_gif::is_animated_gif;
@@ -15,21 +15,17 @@ pub fn create_thumbnail(
path: &PathBuf,
out_dir: &PathBuf,
target: TargetDimension,
-) -> io::Result<PathBuf> {
- let thumbnail_path = out_dir.join(path.file_name().unwrap());
+) -> Result<PathBuf, ThumbnailError> {
+ let file_name = path.file_name().ok_or(ThumbnailError::MissingFileName)?;
+ let thumbnail_path = out_dir.join(file_name);
create_parent_directory(&thumbnail_path)?;
// Make sure we don't overwrite the original image with a thumbnail
if *path == thumbnail_path {
- return Err(io::Error::new(
- io::ErrorKind::InvalidData,
- "Cannot write thumbnail to the same directory as the original image",
- ));
+ return Err(ThumbnailError::SameInputOutputPath);
}
- assert!(*path != thumbnail_path);
- let (new_width, new_height) = get_thumbnail_dimensions(&path, target)
- .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e.to_string()))?;
+ let (new_width, new_height) = get_thumbnail_dimensions(&path, target)?;
if is_animated_gif(path)? {
create_animated_gif_thumbnail(path, out_dir, new_width, new_height)
@@ -174,10 +170,20 @@ pub fn create_animated_gif_thumbnail(
out_dir: &PathBuf,
width: u32,
height: u32,
-) -> io::Result<PathBuf> {
- let file_name = gif_path.file_name().unwrap();
+) -> Result<PathBuf, ThumbnailError> {
+ let file_name = gif_path
+ .file_name()
+ .ok_or(ThumbnailError::MissingFileName)?;
+
let thumbnail_path = out_dir.join(file_name).with_extension("mp4");
+ let gif_path_str = gif_path
+ .to_str()
+ .ok_or(ThumbnailError::PathConversionError)?;
+ let thumbnail_path_str = thumbnail_path
+ .to_str()
+ .ok_or(ThumbnailError::PathConversionError)?;
+
// There's a subtlety here with ffmpeg I don't understand fully -- if
// the width/height aren't even, it doesn't create the MP4, instead
// failing with the error:
@@ -191,26 +197,23 @@ pub fn create_animated_gif_thumbnail(
let output = Command::new("ffmpeg")
.args([
"-i",
- gif_path.to_str().unwrap(),
+ gif_path_str,
"-movflags",
"faststart",
"-pix_fmt",
"yuv420p",
"-vf",
&dimension_str,
- thumbnail_path.to_str().unwrap(),
+ thumbnail_path_str,
])
.output()
- .expect("failed to create thumbnail");
+ .map_err(|e| ThumbnailError::CommandFailed(format!("Failed to run ffmpeg: {}", e)))?;
if output.status.success() {
Ok(thumbnail_path)
} else {
- let error_message = format!(
- "Unable to invoke ffmpeg!\nstderr from ffmpeg:\n{}",
- str::from_utf8(&output.stderr).unwrap()
- );
- Err(io::Error::new(io::ErrorKind::Other, error_message))
+ let stderr = str::from_utf8(&output.stderr)?;
+ Err(ThumbnailError::CommandFailed(stderr.to_string()))
}
}
@@ -218,22 +221,23 @@ pub fn create_animated_gif_thumbnail(
///
/// This function assumes that the original image file definitely exists.
///
-/// TODO: Get rid of the use of `unwrap()` in this code.
-///
pub fn create_static_thumbnail(
image_path: &PathBuf,
out_dir: &PathBuf,
width: u32,
height: u32,
-) -> io::Result<PathBuf> {
- let file_name = image_path.file_name().unwrap();
+) -> Result<PathBuf, ThumbnailError> {
+ let file_name = image_path
+ .file_name()
+ .ok_or(ThumbnailError::MissingFileName)?;
+
let thumbnail_path = out_dir.join(file_name);
- let img = image::open(image_path).unwrap();
+ let img = image::open(image_path).map_err(ThumbnailError::ImageOpenError)?;
img.resize(width, height, FilterType::Lanczos3)
.save(&thumbnail_path)
- .unwrap();
+ .map_err(ThumbnailError::ImageSaveError)?;
Ok(thumbnail_path)
}
src/errors.rs (0) → src/errors.rs (1737)
diff --git a/src/errors.rs b/src/errors.rs
new file mode 100644
index 0000000..f01db6c
--- /dev/null
+++ b/src/errors.rs
@@ -0,0 +1,54 @@
+use std::fmt;
+use std::io;
+
+use image::ImageError;
+
+#[derive(Debug)]
+pub enum ThumbnailError {
+ MissingFileName,
+ ImageOpenError(ImageError),
+ ImageSaveError(ImageError),
+ CommandFailed(String),
+ Utf8Error(std::str::Utf8Error),
+ PathConversionError,
+ SameInputOutputPath,
+ IoError(std::io::Error),
+}
+
+impl fmt::Display for ThumbnailError {
+ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
+ match self {
+ ThumbnailError::MissingFileName => write!(f, "Image path is missing a file name"),
+ ThumbnailError::ImageOpenError(e) => write!(f, "Failed to open image: {}", e),
+ ThumbnailError::ImageSaveError(e) => write!(f, "Failed to save thumbnail: {}", e),
+ ThumbnailError::CommandFailed(msg) => write!(f, "ffmpeg command failed: {}", msg),
+ ThumbnailError::Utf8Error(e) => write!(f, "Failed to decode ffmpeg output: {}", e),
+ ThumbnailError::PathConversionError => write!(f, "Failed to convert path to string"),
+ ThumbnailError::SameInputOutputPath => write!(
+ f,
+ "Cannot write thumbnail to the same path as the original image"
+ ),
+ ThumbnailError::IoError(e) => write!(f, "I/O error: {}", e),
+ }
+ }
+}
+
+impl std::error::Error for ThumbnailError {}
+
+impl From<ImageError> for ThumbnailError {
+ fn from(err: ImageError) -> Self {
+ ThumbnailError::ImageOpenError(err)
+ }
+}
+
+impl From<std::str::Utf8Error> for ThumbnailError {
+ fn from(err: std::str::Utf8Error) -> Self {
+ ThumbnailError::Utf8Error(err)
+ }
+}
+
+impl From<io::Error> for ThumbnailError {
+ fn from(err: io::Error) -> Self {
+ ThumbnailError::IoError(err)
+ }
+}
src/get_thumbnail_dimensions.rs (3810) → src/get_thumbnail_dimensions.rs (3836)
diff --git a/src/get_thumbnail_dimensions.rs b/src/get_thumbnail_dimensions.rs
index 95c9f1e..ae71c1d 100644
--- a/src/get_thumbnail_dimensions.rs
+++ b/src/get_thumbnail_dimensions.rs
@@ -2,6 +2,8 @@ use std::path::PathBuf;
use image::GenericImageView;
+use crate::errors::ThumbnailError;
+
/// Represents the target dimensions of the thumbnail.
///
/// The user can choose a max width, or a max height, but not both.
@@ -26,7 +28,7 @@ pub enum TargetDimension {
pub fn get_thumbnail_dimensions(
path: &PathBuf,
target: TargetDimension,
-) -> Result<(u32, u32), image::error::ImageError> {
+) -> Result<(u32, u32), ThumbnailError> {
let img = image::open(path)?;
let (new_width, new_height) = match target {
src/main.rs (6436) → src/main.rs (6498)
diff --git a/src/main.rs b/src/main.rs
index 827fdb7..1de30d1 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -6,6 +6,7 @@ use clap::{ArgGroup, Parser};
mod create_parent_directory;
mod create_thumbnail;
+mod errors;
mod get_thumbnail_dimensions;
mod is_animated_gif;
@@ -136,7 +137,7 @@ mod test_cli {
.failure()
.code(1)
.stdout("")
- .stderr("No such file or directory (os error 2)\n");
+ .stderr("Failed to open image: No such file or directory (os error 2)\n");
}
#[test]
@@ -148,7 +149,7 @@ mod test_cli {
.failure()
.code(1)
.stdout("")
- .stderr("The file extension `.\"toml\"` was not recognized as an image format\n");
+ .stderr("Failed to open image: The file extension `.\"toml\"` was not recognized as an image format\n");
}
// TODO: Improve this error message.
@@ -164,7 +165,7 @@ mod test_cli {
.failure()
.code(1)
.stdout("")
- .stderr("File exists (os error 17)\n");
+ .stderr("I/O error: File exists (os error 17)\n");
}
#[test]
@@ -176,7 +177,7 @@ mod test_cli {
.failure()
.code(1)
.stdout("")
- .stderr("Cannot write thumbnail to the same directory as the original image\n");
+ .stderr("Cannot write thumbnail to the same path as the original image\n");
}
#[test]