Use Result<T, Error> instead of panicking.

Affects Sdl2Input, Sdl2Output, and WavDecoder constructors.
thoren-d · Oct 14, 2020 · 2b82df9 · 2b82df9
1 parent 2b4df5d
commit 2b82df9
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Showing 8 changed files with 90 additions and 50 deletions.
diff --git a/README.md b/README.md
@@ -19,14 +19,15 @@ programming, but should be flexible enough for other applications as well.
 fn main() -> Result<(), Box<dyn std::error::Error>> {
     use std::time::Duration;
     use timbre::prelude::*;
+
     // SDL setup.
     let sdl = sdl2::init()?;
     let audio = sdl.audio()?;
 
     // Inputs
-    let mut microphone = timbre::drivers::Sdl2Input::new(&audio);
+    let mut microphone = timbre::drivers::Sdl2Input::new(&audio)?;
     microphone.resume();
-    let music = timbre::decoders::WavDecoder::from_file("./music.wav");
+    let music = timbre::decoders::WavDecoder::from_file("./assets/music-stereo-f32.wav")?;
 
     // Apply effects
     let microphone = timbre::effects::Echo::new(microphone.source(),
@@ -39,12 +40,11 @@ fn main() -> Result<(), Box<dyn std::error::Error>> {
     mixer.add_source(music.into_shared());
 
     // Output
-    let mut speaker = timbre::drivers::Sdl2Output::new(&audio);
+    let mut speaker = timbre::drivers::Sdl2Output::new(&audio)?;
     speaker.set_source(mixer.into_shared());
     speaker.resume();
 
     std::thread::sleep(Duration::from_secs_f32(10.0));
-
     Ok(())
 }
 ```

diff --git a/examples/effects.rs b/examples/effects.rs
@@ -14,8 +14,8 @@ fn main() -> Result<(), Box<dyn Error>> {
     let sdl = sdl2::init()?;
     let audio = sdl.audio()?;
 
-    let track1 = WavDecoder::from_file("./assets/music-stereo-f32.wav");
-    let track2 = WavDecoder::new(std::fs::File::open("./assets/music-stereo-i16.wav")?);
+    let track1 = WavDecoder::from_file("./assets/music-stereo-f32.wav")?;
+    let track2 = WavDecoder::new(std::fs::File::open("./assets/music-stereo-i16.wav")?)?;
 
     let low_pass = LowPass::new(track1.into_shared(), 300.0);
     let high_pass = HighPass::new(track2.into_shared(), 4000.0);
@@ -26,7 +26,7 @@ fn main() -> Result<(), Box<dyn Error>> {
 
     let echo = Echo::new(mixer.into_shared(), Duration::from_secs_f32(0.5), 0.7);
 
-    let mut output = Sdl2Output::new(&audio);
+    let mut output = Sdl2Output::new(&audio)?;
     output.set_source(echo.into_shared());
     output.resume();
 

diff --git a/examples/listen_to_mic.rs b/examples/listen_to_mic.rs
@@ -12,8 +12,8 @@ fn main() -> Result<(), Box<dyn Error>> {
     let sdl = sdl2::init()?;
     let audio = sdl.audio()?;
 
-    let mut mic = Sdl2Input::new(&audio);
-    let mut output = Sdl2Output::new(&audio);
+    let mut mic = Sdl2Input::new(&audio)?;
+    let mut output = Sdl2Output::new(&audio)?;
 
     mic.resume();
     output.set_source(mic.source());

diff --git a/src/decoders/wav_decoder.rs b/src/decoders/wav_decoder.rs
@@ -1,4 +1,4 @@
-use crate::{core::AudioBuffer, AudioFormat, AudioSource, ReadResult};
+use crate::{core::AudioBuffer, AudioFormat, AudioSource, Error, ReadResult};
 
 use sdl2::{
     audio::{AudioFormatNum, AudioSpecWAV},
@@ -21,65 +21,68 @@ pub struct WavDecoder {
 impl WavDecoder {
     /// Construct a WavDecoder that reads from a [`std::io::Read`](std::io::Read).
     ///
-    /// # Panics
+    /// # Errors
     ///
-    /// If the WAV file in `read` in corrupted or empty.
+    /// If the WAV file in `read` in corrupted or empty, will return the underlying SDL error.
     ///
     /// # Examples
     /// ```
     /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// use timbre::decoders::WavDecoder;
     ///
-    /// let decoder = WavDecoder::new(std::fs::File::open("./assets/music-mono-f32.wav")?);
+    /// let decoder = WavDecoder::new(std::fs::File::open("./assets/music-mono-f32.wav")?)?;
     /// # Ok(())
     /// # }
     /// ```
     #[instrument(name = "WavDecoder::new", skip(read))]
-    pub fn new<R: Read>(mut read: R) -> Self {
+    pub fn new<R: Read>(mut read: R) -> Result<Self, Error> {
         let mut read_buffer = Vec::new();
-        let mut rwops = RWops::from_read(&mut read, &mut read_buffer).unwrap();
-        let wav_data = AudioSpecWAV::load_wav_rw(&mut rwops).unwrap();
+        let mut rwops = RWops::from_read(&mut read, &mut read_buffer).map_err(Error::from_sdl)?;
+        let wav_data = AudioSpecWAV::load_wav_rw(&mut rwops).map_err(Error::from_sdl)?;
         let data = convert_samples(wav_data.buffer(), wav_data.format);
 
         let format = AudioFormat {
             channels: wav_data.channels,
             sample_rate: wav_data.freq as u32,
         };
 
-        WavDecoder {
+        Ok(WavDecoder {
             data,
             format,
             position: 0,
-        }
+        })
     }
 
     /// Construct a WavDecoder the file given by `path`.
     ///
-    /// # Panics
+    /// # Errors
     ///
-    /// If the file cannot be opened or is not a valid WAV file.
+    /// If the file cannot be opened or is not a valid WAV file, will return the underlying SDL error.
     ///
     /// # Examples
     /// ```
+    /// # fn main() -> Result<(), Box<dyn std::error::Error>> {
     /// use timbre::decoders::WavDecoder;
     ///
-    /// let decoder = WavDecoder::from_file("./assets/music-stereo-i16.wav");
+    /// let decoder = WavDecoder::from_file("./assets/music-stereo-i16.wav")?;
+    /// # Ok(())
+    /// }
     /// ```
     #[instrument(name = "WavDecoder::from_file")]
-    pub fn from_file(path: &str) -> Self {
-        let wav_data = AudioSpecWAV::load_wav(path).unwrap();
+    pub fn from_file(path: &str) -> Result<Self, Error> {
+        let wav_data = AudioSpecWAV::load_wav(path).map_err(Error::from_sdl)?;
         let data = convert_samples(wav_data.buffer(), wav_data.format);
 
         let format = AudioFormat {
             channels: wav_data.channels,
             sample_rate: wav_data.freq as u32,
         };
 
-        WavDecoder {
+        Ok(WavDecoder {
             data,
             format,
             position: 0,
-        }
+        })
     }
 }
 

diff --git a/src/drivers/sdl2_input.rs b/src/drivers/sdl2_input.rs
@@ -1,6 +1,6 @@
 use crate::{
     core::{AudioBuffer, SharedAudioSource},
-    AudioFormat, AudioSource, ReadResult,
+    AudioFormat, AudioSource, Error, ReadResult,
 };
 
 use std::collections::VecDeque;
@@ -19,8 +19,8 @@ use tracing::{info, instrument};
 /// let sdl = sdl2::init()?;
 /// let audio = sdl.audio()?;
 ///
-/// let mut microphone = Sdl2Input::new(&audio);
-/// let mut speaker = Sdl2Output::new(&audio);
+/// let mut microphone = Sdl2Input::new(&audio)?;
+/// let mut speaker = Sdl2Output::new(&audio)?;
 /// microphone.resume();
 /// speaker.set_source(microphone.source());
 /// speaker.resume();
@@ -59,7 +59,7 @@ impl Sdl2Input {
     ///
     /// * `subsystem` -- An SDL [`AudioSubystem`](sdl2::AudioSubsystem) used to create a capture device.
     ///
-    /// # Panics
+    /// # Errors
     ///
     /// If SDL fails to open the device.
     ///
@@ -71,11 +71,11 @@ impl Sdl2Input {
     /// let sdl = sdl2::init()?;
     /// let audio = sdl.audio()?;
     ///
-    /// let microphone = Sdl2Input::new(&audio);
+    /// let microphone = Sdl2Input::new(&audio)?;
     /// # Ok(())
     /// # }
     /// ```
-    pub fn new(subsystem: &sdl2::AudioSubsystem) -> Self {
+    pub fn new(subsystem: &sdl2::AudioSubsystem) -> Result<Self, Error> {
         Sdl2Input::with_format(
             subsystem,
             AudioFormat {
@@ -94,7 +94,7 @@ impl Sdl2Input {
     /// * `subsystem` -- An SDL [`AudioSubystem`](sdl2::AudioSubsystem) used to create a capture device.
     /// * `format` -- The format to request for this input device.
     ///
-    /// # Panics
+    /// # Errors
     ///
     /// If SDL fails to open the device.
     ///
@@ -107,11 +107,14 @@ impl Sdl2Input {
     /// let audio = sdl.audio()?;
     ///
     /// let format = AudioFormat { channels: 2, sample_rate: 44100 };
-    /// let microphone = Sdl2Input::with_format(&audio, format);
+    /// let microphone = Sdl2Input::with_format(&audio, format)?;
     /// # Ok(())
     /// # }
     /// ```
-    pub fn with_format(subsystem: &sdl2::AudioSubsystem, format: AudioFormat) -> Self {
+    pub fn with_format(
+        subsystem: &sdl2::AudioSubsystem,
+        format: AudioFormat,
+    ) -> Result<Self, Error> {
         let desired_spec = AudioSpecDesired {
             freq: Some(format.sample_rate as i32),
             channels: Some(format.channels),
@@ -129,9 +132,9 @@ impl Sdl2Input {
                     format: spec.into(),
                 }
             })
-            .unwrap();
+            .map_err(Error::from_sdl)?;
 
-        Sdl2Input { device, buffer }
+        Ok(Sdl2Input { device, buffer })
     }
 
     /// Return the device's chosen format.

diff --git a/src/drivers/sdl2_output.rs b/src/drivers/sdl2_output.rs
@@ -1,6 +1,6 @@
 use crate::{
     core::{AudioBuffer, SharedAudioSource},
-    AudioFormat, StreamState,
+    AudioFormat, Error, StreamState,
 };
 
 use sdl2::audio::{AudioCallback, AudioFormatNum, AudioSpecDesired};
@@ -47,8 +47,8 @@ impl AudioCallback for Callback {
 /// let sdl = sdl2::init()?;
 /// let audio = sdl.audio()?;
 ///
-/// let mut microphone = Sdl2Input::new(&audio);
-/// let mut speaker = Sdl2Output::new(&audio);
+/// let mut microphone = Sdl2Input::new(&audio)?;
+/// let mut speaker = Sdl2Output::new(&audio)?;
 /// microphone.resume();
 /// speaker.set_source(microphone.source());
 /// speaker.resume();
@@ -68,7 +68,7 @@ impl Sdl2Output {
     ///
     /// * `subsystem` -- An SDL [`AudioSubystem`](sdl2::AudioSubsystem) used to create an output device.
     ///
-    /// # Panics
+    /// # Errors
     ///
     /// If SDL fails to open the device.
     ///
@@ -80,11 +80,11 @@ impl Sdl2Output {
     /// let sdl = sdl2::init()?;
     /// let audio = sdl.audio()?;
     ///
-    /// let speaker = Sdl2Output::new(&audio);
+    /// let speaker = Sdl2Output::new(&audio)?;
     /// # Ok(())
     /// # }
     /// ```
-    pub fn new(subsystem: &sdl2::AudioSubsystem) -> Sdl2Output {
+    pub fn new(subsystem: &sdl2::AudioSubsystem) -> Result<Self, Error> {
         Sdl2Output::with_format(
             subsystem,
             AudioFormat {
@@ -103,7 +103,7 @@ impl Sdl2Output {
     /// * `subsystem` -- An SDL [`AudioSubystem`](sdl2::AudioSubsystem) used to create an output device.
     /// * `format` -- The format to request for this output device.
     ///
-    /// # Panics
+    /// # Errors
     ///
     /// If SDL fails to open the device.
     ///
@@ -115,11 +115,14 @@ impl Sdl2Output {
     /// let sdl = sdl2::init()?;
     /// let audio = sdl.audio()?;
     ///
-    /// let speaker = Sdl2Output::new(&audio);
+    /// let speaker = Sdl2Output::new(&audio)?;
     /// # Ok(())
     /// # }
     /// ```
-    pub fn with_format(subsystem: &sdl2::AudioSubsystem, format: AudioFormat) -> Sdl2Output {
+    pub fn with_format(
+        subsystem: &sdl2::AudioSubsystem,
+        format: AudioFormat,
+    ) -> Result<Self, Error> {
         let desired_spec = AudioSpecDesired {
             freq: Some(format.sample_rate as i32),
             channels: Some(format.channels),
@@ -135,9 +138,9 @@ impl Sdl2Output {
                     source: None,
                 }
             })
-            .unwrap();
+            .map_err(Error::from_sdl)?;
 
-        Sdl2Output { device }
+        Ok(Sdl2Output { device })
     }
 
     /// Set the source of audio to output.

diff --git a/src/error.rs b/src/error.rs
@@ -0,0 +1,28 @@
+/// Unified error type.
+#[derive(Debug)]
+pub enum Error {
+    /// Wraps a [`std::io::Error`](std::io::Error), such as file not found, etc.
+    IoError(std::io::Error),
+    /// Wraps an error from SDL2.
+    SdlError(String),
+}
+
+impl Error {
+    pub(crate) fn from_sdl(err: String) -> Error {
+        Error::SdlError(err)
+    }
+}
+
+impl std::fmt::Display for Error {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_fmt(format_args!("{:?}", self))
+    }
+}
+
+impl std::error::Error for Error {}
+
+impl From<std::io::Error> for Error {
+    fn from(error: std::io::Error) -> Self {
+        Error::IoError(error)
+    }
+}
diff --git a/src/lib.rs b/src/lib.rs
@@ -12,14 +12,15 @@
 //! # std::env::set_var("SDL_AUDIODRIVER", "dummy");
 //! use std::time::Duration;
 //! use timbre::prelude::*;
+//!
 //! // SDL setup.
 //! let sdl = sdl2::init()?;
 //! let audio = sdl.audio()?;
 //!
 //! // Inputs
-//! let mut microphone = timbre::drivers::Sdl2Input::new(&audio);
+//! let mut microphone = timbre::drivers::Sdl2Input::new(&audio)?;
 //! microphone.resume();
-//! let music = timbre::decoders::WavDecoder::from_file("./assets/music-stereo-f32.wav");
+//! let music = timbre::decoders::WavDecoder::from_file("./assets/music-stereo-f32.wav")?;
 //!
 //! // Apply effects
 //! let microphone = timbre::effects::Echo::new(microphone.source(),
@@ -32,7 +33,7 @@
 //! mixer.add_source(music.into_shared());
 //!
 //! // Output
-//! let mut speaker = timbre::drivers::Sdl2Output::new(&audio);
+//! let mut speaker = timbre::drivers::Sdl2Output::new(&audio)?;
 //! speaker.set_source(mixer.into_shared());
 //! speaker.resume();
 //!
@@ -41,6 +42,8 @@
 
 mod core;
 pub use crate::core::*;
+mod error;
+pub use crate::error::*;
 
 pub mod decoders;
 pub mod drivers;