Commit Graph

9 Commits

Author SHA1 Message Date
mitchmindtree e8a05379c2 [WIP] Introduce a `Host` API
This is an implementation of the API described at #204. Please see that
issue for more details on the motivation.

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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.
2019-06-24 21:45:04 +02:00
mitchmindtree c72bafd8ab Update examples eprintln to more accurately reflect error 2019-06-24 21:13:07 +02:00
mitchmindtree c05d2916b1 Remove `StreamEvent` in favour of `StreamDataResult` 2019-06-24 20:43:27 +02:00
mitchmindtree 39cd5d0084 Update examples for addition of new StreamEvent API 2019-06-22 00:10:40 +02:00
mitchmindtree 0b6e66d38e Update examples to use std Termination 2019-06-21 14:55:21 +02:00
mitchmindtree eae0e18714 Add `PlayStreamError` and `PauseStreamError`.
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.
2019-06-21 03:04:15 +02:00
mitchmindtree fbb97f51ef Update examples for DeviceNameError 2019-06-21 01:37:55 +02:00
Mohanson 6ceb3a215f
Update feedback.rs 2019-06-19 10:34:12 +08:00
mitchmindtree c20978fc01 Add an example that demonstrates feeding input directly to output with some latency 2018-02-17 15:33:00 +11:00