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Remove std `Error` implementations in favour of using `failure` 

This will make adding new errors in the following commits towards better
error handling a lot easier.
This commit is contained in:
mitchmindtree 2019-06-07 21:04:08 +02:00
parent 9c04bf7400
commit 1275db805b
2 changed files with 19 additions and 83 deletions
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1
Cargo.toml
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@ -9,6 +9,7 @@ license = "Apache-2.0"
keywords = ["audio", "sound"]
[dependencies]
failure = "0.1.5"
lazy_static = "1.3"
[dev-dependencies]

101
src/lib.rs
View File

@ -114,10 +114,10 @@
#![recursion_limit = "512"]
extern crate failure;
#[cfg(target_os = "windows")]
#[macro_use]
extern crate lazy_static;
// Extern crate declarations with `#[macro_use]` must unfortunately be at crate root.
#[cfg(target_os = "emscripten")]
#[macro_use]
@ -129,7 +129,7 @@ pub use samples_formats::{Sample, SampleFormat};
target_os = "macos", target_os = "ios", target_os = "emscripten")))]
use null as cpal_impl;
use std::error::Error;
use failure::Fail;
use std::fmt;
use std::iter;
use std::ops::{Deref, DerefMut};
@ -280,39 +280,50 @@ pub struct SupportedInputFormats(cpal_impl::SupportedInputFormats);
pub struct SupportedOutputFormats(cpal_impl::SupportedOutputFormats);
/// Error that can happen when enumerating the list of supported formats.
#[derive(Debug)]
#[derive(Debug, Fail)]
pub enum FormatsEnumerationError {
/// The device no longer exists. This can happen if the device is disconnected while the
/// program is running.
#[fail(display = "The requested device is no longer available. For example, it has been unplugged.")]
DeviceNotAvailable,
/// We called something the C-Layer did not understand
#[fail(display = "Invalid argument passed to the backend. For example, this happens when trying to read capture capabilities when the device does not support it.")]
InvalidArgument,
/// The C-Layer returned an error we don't know about
#[fail(display = "An unknown error in the backend occured.")]
Unknown
}
/// May occur when attempting to request the default input or output stream format from a `Device`.
#[derive(Debug)]
#[derive(Debug, Fail)]
pub enum DefaultFormatError {
/// The device no longer exists. This can happen if the device is disconnected while the
/// program is running.
#[fail(display = "The requested device is no longer available. For example, it has been unplugged.")]
DeviceNotAvailable,
/// Returned if e.g. the default input format was requested on an output-only audio device.
#[fail(display = "The requested stream type is not supported by the device.")]
StreamTypeNotSupported,
}
/// Error that can happen when creating a `Voice`.
#[derive(Debug)]
#[derive(Debug, Fail)]
pub enum CreationError {
/// The device no longer exists. This can happen if the device is disconnected while the
/// program is running.
#[fail(display = "The requested device is no longer available. For example, it has been unplugged.")]
DeviceNotAvailable,
/// The required format is not supported.
#[fail(display = "The requested stream format is not supported by the device.")]
FormatNotSupported,
/// An ALSA device function was called with a feature it does not support
/// (trying to use capture capabilities on an output only format yields this)
/// We called something the C-Layer did not understand
///
/// On ALSA device functions called with a feature they do not support will yield this. E.g.
/// Trying to use capture capabilities on an output only format yields this.
#[fail(display = "The requested device does not support this capability (invalid argument)")]
InvalidArgument,
/// The C-Layer returned an error we don't know about
#[fail(display = "An unknown error in the Backend occured")]
Unknown,
}
@ -693,82 +704,6 @@ impl Iterator for SupportedOutputFormats {
}
}
impl fmt::Display for FormatsEnumerationError {
#[inline]
fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(fmt, "{}", self.description())
}
}
impl Error for FormatsEnumerationError {
#[inline]
fn description(&self) -> &str {
match self {
&FormatsEnumerationError::DeviceNotAvailable => {
"The requested device is no longer available (for example, it has been unplugged)."
},
&FormatsEnumerationError::InvalidArgument => {
"Invalid argument passed to the Backend (This happens when trying to read for example capture capabilities but the device does not support it -> dmix on Linux)"
},
&FormatsEnumerationError::Unknown => {
"An unknown error in the Backend occured"
},
}
}
}
impl fmt::Display for CreationError {
#[inline]
fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(fmt, "{}", self.description())
}
}
impl Error for CreationError {
#[inline]
fn description(&self) -> &str {
match self {
&CreationError::DeviceNotAvailable => {
"The requested device is no longer available (for example, it has been unplugged)."
},
&CreationError::FormatNotSupported => {
"The requested samples format is not supported by the device."
},
&CreationError::InvalidArgument => {
"The requested device does not support this capability (invalid argument)"
}
&CreationError::Unknown => {
"An unknown error in the Backend occured"
},
}
}
}
impl fmt::Display for DefaultFormatError {
#[inline]
fn fmt(&self, fmt: &mut fmt::Formatter) -> Result<(), fmt::Error> {
write!(fmt, "{}", self.description())
}
}
impl Error for DefaultFormatError {
#[inline]
fn description(&self) -> &str {
match self {
&DefaultFormatError::DeviceNotAvailable => {
CreationError::DeviceNotAvailable.description()
},
&DefaultFormatError::StreamTypeNotSupported => {
"The requested stream type is not supported by the device."
},
}
}
}
// If a backend does not provide an API for retrieving supported formats, we query it with a bunch
// of commonly used rates. This is always the case for wasapi and is sometimes the case for alsa.
//