Using an unsigned representation was problematic as some platforms
provide no exact "capture" instant. As a result, we need to calculate
the instant of capture by subtracting the buffer duration from the
callback duration. In some cases this would occasionally cause the
unsigned representation to underflow unnecessarily.
I began on an implementation of the timestamp API described in #363 but
quickly realised that it might be best to land the API for providing
extra information to the user's callback first.
This PR adds two new types: `InputCallbackInfo` and `OutputCallbackInfo`.
These types are delivered to the user's data callback as a new, second
argument.
While these types are currently empty, the intention is for these types
to provide information relevant to the current request for or delivery
of data. This includes:
- Timestamp information #363.
- Flags related to the state of the stream (e.g buffer
underflow/overflow).
In order to maintain flexibility to avoid breaking things, I figure we
can keep the fields of these types private and provide methods for
retrieving this info.
@Ralith, @ishitatsuyuki does this seem OK to you?
This should give the user a higher confidence that, if they have a
`SupportedStreamConfig` format type that it is actually supported.
Also updates the `raw` stream builder methods to take a `StreamConfig`
and `SampleFormat` as separate arguments for flexibility.
**Backends Updated**
- [x] null
- [x] alsa
- [ ] emscripten
- [ ] coreaudio
- [ ] wasapi
- [ ] asio
This implements the changes described at #370.
This commit implements only the `null` and `alsa` backends - the rest
will be implemented in follow-up commits.
Closes#370.
Seeing as a few large refactors have landed recently, I thought I'd take
this opportunity to do a `cargo fmt` run and standardise on the default
rustfmt settings.
This is a potential alternative to #359. This PR is based on #359.
This approach opts for a dynamically checked sample type approach with
the aim of minimising compile time and binary size.
You can read more discussion on this [here](https://github.com/RustAudio/cpal/pull/359#issuecomment-575931461)
Implemented backends:
- [x] null
- [x] ALSA
- [ ] CoreAudio
- [ ] WASAPI
- [ ] ASIO
- [ ] Emscripten
This is an implementation of the planned changes described in #119.
For a quick overview of how the API has changed, check out the updated
examples.
**TODO:**
- [x] Update API.
- [x] Update examples.
- [ ] Remove `data_type` field from `Format` (see [here](https://github.com/RustAudio/cpal/issues/119#issuecomment-573788380)).
- Update backends:
- [x] null
- [x] ALSA
- [ ] ASIO
- [ ] WASAPI
- [ ] CoreAudio
- [ ] Emscripten
Closes#119Closes#260
Currently CPAL only really uses `failure` for its `derive` capabilities
and the ability to easily generate implementations for `Display`. That
said there are a few issues with using the `failure` crate:
- `failure` does not provie a `std::error::Error` implementation without
first converting error types into `failure::Error`.
- It leaks significantly into the public API and expects downstream
users to also depend on `failure` and the non-std `Fail` trait for
their own error handling.
- Solved problems such as downcasting of causal errors which have since
been addressed in `std`.
- Provides application-friendly `Fail` trait and `failure::Error` type,
not particularly useful to libraries like CPAL.
The [`thiserror` crate](https://github.com/dtolnay/thiserror) is better
targeted towards libraries, does not leak into the public API while
providing easy generation of `Display`, `From` and `std::error::Error`
implementations including proper handling of the newish
`std::error::Error::source` method.
Currently not compiling - still need to address some global items within
asio-sys, including the `set_callback` function and the double buffer
globals.
This is a draft implementation of #294. I'll leave this open for
feedback and potentially better trait naming suggestions or better
solutions in general!
cc @ishitatsuyuki
Re-exports host-specific types so that they are available within the
platform module if necessary (e.g. host::asla::Host as AlsaHost).
Allows for converting platform-specific host types (e.g. AlsaHost) into
the dynamically dispatched type generated for the target platform
(`Host`).
This is an implementation of the API described at #204. Please see that
issue for more details on the motivation.
-----
A **Host** provides access to the available audio devices on the system.
Some platforms have more than one host available, e.g.
wasapi/asio/dsound on windows, alsa/pulse/jack on linux and so on. As a
result, some audio devices are only available on certain hosts, while
others are only available on other hosts. Every platform supported by
CPAL has at least one **DefaultHost** that is guaranteed to be available
(alsa, wasapi and coreaudio). Currently, the default hosts are the only
hosts supported by CPAL, however this will change as of landing #221 (cc
@freesig). These changes should also accommodate support for other hosts
such as jack #250 (cc @derekdreery) and pulseaudio (cc @knappador) #259.
This introduces a suite of traits allowing for both compile time and
runtime dispatch of different hosts and their uniquely associated device
and event loop types.
A new private **host** module has been added containing the individual
host implementations, each in their own submodule gated to the platforms
on which they are available.
A new **platform** module has been added containing platform-specific
items, including a dynamically dispatched host type that allows for
easily switching between hosts at runtime.
The **ALL_HOSTS** slice contains a **HostId** for each host supported on
the current platform. The **available_hosts** function produces a
**HostId** for each host that is currently *available* on the platform.
The **host_from_id** function allows for initialising a host from its
associated ID, failing with a **HostUnavailable** error. The
**default_host** function returns the default host and should never
fail.
Please see the examples for a demonstration of the change in usage. For
the most part, things look the same at the surface level, however the
role of device enumeration and creating the event loop have been moved
from global functions to host methods. The enumerate.rs example has been
updated to enumerate all devices for each host, not just the default.
**TODO**
- [x] Add the new **Host** API
- [x] Update examples for the new API.
- [x] ALSA host
- [ ] WASAPI host
- [ ] CoreAudio host
- [ ] Emscripten host **Follow-up PR**
- [ ] ASIO host #221
cc @ishitatsuyuki more to review for you if you're interested, but it
might be easier after #288 lands and this gets rebased.
This adds the following types:
- `StreamEvent`
- `CloseStreamCause`
- `StreamError`
These allow for notifying the user of the following events:
- A stream has been played.
- A stream has been paused.
- A stream has been closed due to user destroying stream.
- A stream has been closed due to an error.
This allows for properly handling potential failure on macOS. We should
also consider propagating the mutex/channel poison errors through these
new types, especially considering the potential removal of the event
loop in favour of switching over to high-priority audio threads on
windows and linux.
The coreaudio and wasapi backends may both potentially fail to produce
the name associated with a device. This changes the API to allow for
returning the errors in these cases.
See the documentation for both new errors for details.
The new `DevicesError` has been added to allow for returning errors when
enumerating devices. This has allowed to remove multiple potential
`panic!`s in each of the alsa, coreaudio and wasapi backends.
