Removed useless locks to DeviceContainer::m_devices_mutex, as they were all already protected by m_devices_population_mutex.
We have no interest in blocking other threads that were potentially reading devices at the same time so this seems fine.
This simplifies the code, and I've adjusted a few comments which mentioned possible deadlock that should now be totally gone.
The deadlock could have happen if a thread directly called EmulatedController::UpdateReferences(), while another another thread also reached EmulatedController::UpdateReferences() within a call to ControllerInterface::UpdateDevices(), as the mentioned function locked both the DeviceContainer::m_devices_mutex and s_get_state_mutex at the same time.
The deadlock was frequent on game emulation startup on Android, due to the UpdateReferences() call in InputConfig::LoadConfig() and the UI thread triggering calls to ControllerInterface::UpdateDevices().
It could also have happened on Desktop if a user pressed "Refresh Devices" manually in the UI while the input config was loading.
Also brought some UpdateReferences() comments and thread safety fixes from https://github.com/dolphin-emu/dolphin/pull/9489
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
This helps us keeping the most important devices (e.g. Mouse and Keyboard) on the top
of the list of devices (they still are on all OSes supported by dolphin
and to make hotplug devices like DSU appear at the bottom.
-Fix Add/Remove/Refresh device safety, devices could be added and removed at the same time, causing missing or duplicated devices (rare but possible)
-Fix other devices population race conditions in ControllerInterface
-Avoid re-creating all devices when dolphin is being shut down
-Avoid re-creating devices when the render window handle has changed (just the relevantr ones now)
-Avoid sending Devices Changed events if devices haven't actually changed
-Made most devices populations will be made async, to increase performance and avoid hanging the host or CPU thread on manual devices refresh
A "devices changed" callback could have ended up waiting on another thread that was also populating devices
and waiting on the previous thread to release the callbacks mutex.
-Reworked thread waits to never hang the Host thread for more than a really small time
(e.g. when disabling DSU its thread now closes almost immediately)
-Improve robustness when a large amount of devices are connected
-Add devices disconnection detection (they'd stay there forever until manually refreshed)
-add a way to reset their value (from the mappings UI)
-fix "memory leak" where they would never be cleaned,
one would be created every time you wrote a character after a "$"
-fix ability to create variables with an empty string by just writing "$" (+added error for it)
-Add $ operator to the UI operators list, to expose this functionality even more
casting a value to a u32 when it's originally an int, and it's exposed as int to users,
could end up in cases where a negative number would result as a positive one.
This doesn't really affect the value range of the attachment enum,
still I think the code was wrong.
Heavily tested.
NumericSettings support a max, so let's use it.
It might not do much now, but the max and min values will be used to give visual feeback
in the UI in one of my upcoming input PRs
The control expression editor allows line breaks, but the serialization was
losing anything after the first line break (/r /n).
Instead of opting to encode them and decode them on serialization
(which I tried but was not safe, as it would lose /n written in the string by users),
I opted to replace them with a space.
Update references was failing to update the references, causing input to stay nullptr and crashing.
I fixed the case that triggered that, though also added checks against nullptrs for safety.
(cherry picked from commit 4bdcf707555a5568eddff957fa3604975ffb6ed7)
Add ! before unused variables to 'use' them.
Ubuntu-x64 emits warnings for unused variables because gcc decides
it should ignore the void cast around them. See thread for discussion:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66425
Loop index int i was being compared against GetControllerCount() which
returned a size_t. This was the only place GetControllerCount() was
called from so the change of return type doesn't disturb anything else.
Changing the loop index to size_t wouldn't work as well since it's
passed into GetController(), which takes an int and is called from many
places, so it would need a cast anyway on an already busy line.
