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clean up get_state_ex usage and docs
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@Lokathor
Lokathor committed Dec 16, 2023
1 parent 2956814 commit 3008f1b
Showing 1 changed file with 24 additions and 22 deletions.
46 changes: 24 additions & 22 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -54,7 +54,7 @@ type XInputSetStateFunc = unsafe extern "system" fn(DWORD, *mut XINPUT_VIBRATION
type XInputGetCapabilitiesFunc =
unsafe extern "system" fn(DWORD, DWORD, *mut XINPUT_CAPABILITIES) -> DWORD;

// Removed in xinput1_4.dll.
// **Removed** in xinput1_4.dll.
type XInputGetDSoundAudioDeviceGuidsFunc =
unsafe extern "system" fn(DWORD, *mut GUID, *mut GUID) -> DWORD;

Expand All @@ -73,7 +73,7 @@ pub struct XInputHandle {
handle: HMODULE,
xinput_enable: XInputEnableFunc,
xinput_get_state: XInputGetStateFunc,
xinput_get_state_ex: XInputGetStateExFunc,
opt_xinput_get_state_ex: Option<XInputGetStateExFunc>,
xinput_set_state: XInputSetStateFunc,
xinput_get_capabilities: XInputGetCapabilitiesFunc,
opt_xinput_get_keystroke: Option<XInputGetKeystrokeFunc>,
Expand Down Expand Up @@ -223,7 +223,6 @@ impl XInputHandle {
let mut opt_xinput_get_audio_device_ids = None;
let mut opt_xinput_get_dsound_audio_device_guids = None;

// using transmute is so dodgy we'll put that in its own unsafe block.
unsafe {
let enable_ptr = GetProcAddress(xinput_handle, enable_name.as_ptr() as *mut i8);
if !enable_ptr.is_null() {
Expand All @@ -234,7 +233,6 @@ impl XInputHandle {
}
}

// using transmute is so dodgy we'll put that in its own unsafe block.
unsafe {
let get_state_ptr = GetProcAddress(xinput_handle, get_state_name.as_ptr() as *mut i8);
if !get_state_ptr.is_null() {
Expand All @@ -245,7 +243,6 @@ impl XInputHandle {
}
}

// using transmute is so dodgy we'll put that in its own unsafe block.
unsafe {
let get_state_ex_ptr = GetProcAddress(xinput_handle, 100_i32 as winapi::um::winnt::LPCSTR);
if !get_state_ex_ptr.is_null() {
Expand All @@ -256,7 +253,6 @@ impl XInputHandle {
}
}

// using transmute is so dodgy we'll put that in its own unsafe block.
unsafe {
let set_state_ptr = GetProcAddress(xinput_handle, set_state_name.as_ptr() as *mut i8);
if !set_state_ptr.is_null() {
Expand All @@ -267,7 +263,6 @@ impl XInputHandle {
}
}

// using transmute is so dodgy we'll put that in its own unsafe block.
unsafe {
let get_capabilities_ptr =
GetProcAddress(xinput_handle, get_capabilities_name.as_ptr() as *mut i8);
Expand All @@ -279,7 +274,6 @@ impl XInputHandle {
}
}

// using transmute is so dodgy we'll put that in its own unsafe block.
unsafe {
let get_keystroke_ptr = GetProcAddress(xinput_handle, get_keystroke_name.as_ptr() as *mut i8);
if !get_keystroke_ptr.is_null() {
Expand All @@ -290,7 +284,6 @@ impl XInputHandle {
}
}

// using transmute is so dodgy we'll put that in its own unsafe block.
unsafe {
let get_battery_information_ptr = GetProcAddress(
xinput_handle,
Expand All @@ -305,7 +298,6 @@ impl XInputHandle {
}
}

// using transmute is so dodgy we'll put that in its own unsafe block.
unsafe {
let get_dsound_audio_device_guids_ptr = GetProcAddress(
xinput_handle,
Expand All @@ -320,7 +312,6 @@ impl XInputHandle {
}
}

// using transmute is so dodgy we'll put that in its own unsafe block.
unsafe {
let get_audio_device_ids_ptr =
GetProcAddress(xinput_handle, get_audio_device_ids_name.as_ptr() as *mut i8);
Expand All @@ -332,11 +323,9 @@ impl XInputHandle {
}
}

// this is safe because no other code can be loading xinput at the same time as us.
#[allow(clippy::unnecessary_unwrap)]
if opt_xinput_enable.is_some()
&& opt_xinput_get_state.is_some()
&& opt_xinput_get_state_ex.is_some()
&& opt_xinput_get_state.is_some()
&& opt_xinput_set_state.is_some()
&& opt_xinput_get_capabilities.is_some()
{
Expand All @@ -345,9 +334,9 @@ impl XInputHandle {
handle: xinput_handle,
xinput_enable: opt_xinput_enable.unwrap(),
xinput_get_state: opt_xinput_get_state.unwrap(),
xinput_get_state_ex: opt_xinput_get_state_ex.unwrap(),
xinput_set_state: opt_xinput_set_state.unwrap(),
xinput_get_capabilities: opt_xinput_get_capabilities.unwrap(),
opt_xinput_get_state_ex,
opt_xinput_get_keystroke,
opt_xinput_get_battery_information,
_opt_xinput_get_dsound_audio_device_guids: opt_xinput_get_dsound_audio_device_guids,
Expand Down Expand Up @@ -762,11 +751,14 @@ impl XInputHandle {

/// Polls the controller port given for the current controller state.
///
/// This cannot detect the "Guide" button. Use
/// [`get_state_ex`](Self::get_state_ex) for that.
///
/// # Notes
///
/// It is a persistent problem (since ~2007?) with xinput that polling for the
/// data of a controller that isn't connected will cause a long delay. In the
/// area of 500_000 cpu cycles. That's like 2_000 cache misses in a row.
/// It is a persistent problem with xinput (since ~2007?) that polling for the
/// data of a controller that isn't connected will cause a long stall. In the
/// area of 500,000 cpu cycles. That's like 2,000 cache misses in a row.
///
/// Once a controller is detected as not being plugged in you are strongly
/// advised to not poll for its data again next frame. Instead, you should
Expand All @@ -781,8 +773,8 @@ impl XInputHandle {
/// A few things can cause an `Err` value to come back, as explained by the
/// `XInputUsageError` type.
///
/// Most commonly, a controller will simply not be connected. Most people don't
/// have all four slots plugged in all the time.
/// Most commonly, a controller will simply not be connected. Most people
/// don't have all four slots plugged in all the time.
pub fn get_state(&self, user_index: u32) -> Result<XInputState, XInputUsageError> {
if user_index >= 4 {
Err(XInputUsageError::InvalidControllerID)
Expand All @@ -800,13 +792,23 @@ impl XInputHandle {
}
}

/// see get_state, but XINPUT_GAMEPAD_GUIDE in XInputState
/// Works like `get_state`, but can detect the "Guide" button as well.
///
/// ## Failure
///
/// * This function is technically an undocumented API. It was introduced in
/// XInput 1.3, but may not be present in the currently loaded XInput. If
/// it's not available then `XInputNotLoaded` is returned as an `Err`, even
/// when other XInput functions may be available.
pub fn get_state_ex(&self, user_index: u32) -> Result<XInputState, XInputUsageError> {
if user_index >= 4 {
Err(XInputUsageError::InvalidControllerID)
} else {
let mut output: XINPUT_STATE = unsafe { ::std::mem::zeroed() };
let return_status = unsafe { (self.xinput_get_state_ex)(user_index, &mut output) };
let return_status = match self.opt_xinput_get_state_ex {
Some(f) => unsafe { f(user_index, &mut output) },
None => return Err(XInputUsageError::XInputNotLoaded),
};
match return_status {
ERROR_SUCCESS => Ok(XInputState { raw: output }),
ERROR_DEVICE_NOT_CONNECTED => Err(XInputUsageError::DeviceNotConnected),
Expand Down

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