Merge pull request #133 from Sainan/allow-narrow-enumeration

Add HidApi::reset_devices & HidApi::add_devices

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "hidapi"
-version = "2.4.1"
+version = "2.5.0"
 authors = [
     "Roland Ruckerbauer <[email protected]>",
     "Osspial <[email protected]>",

src/hidapi.rs

@@ -19,10 +19,10 @@ const STRING_BUF_LEN: usize = 128;
 pub struct HidApiBackend;
 
 impl HidApiBackend {
-    pub fn get_hid_device_info_vector() -> HidResult<Vec<DeviceInfo>> {
+    pub fn get_hid_device_info_vector(vid: u16, pid: u16) -> HidResult<Vec<DeviceInfo>> {
         let mut device_vector = Vec::with_capacity(8);
 
-        let enumeration = unsafe { ffi::hid_enumerate(0, 0) };
+        let enumeration = unsafe { ffi::hid_enumerate(vid, pid) };
         {
             let mut current_device = enumeration;
 

src/lib.rs

@@ -173,9 +173,11 @@ impl HidApi {
     pub fn new() -> HidResult<Self> {
         lazy_init(true)?;
 
-        let device_list = HidApiBackend::get_hid_device_info_vector()?;
-
-        Ok(HidApi { device_list })
+        let mut api = HidApi {
+            device_list: Vec::with_capacity(8),
+        };
+        api.add_devices(0, 0)?;
+        Ok(api)
     }
 
     /// Create a new hidapi context, in "do not enumerate" mode.
@@ -196,13 +198,28 @@ impl HidApi {
 
     /// Refresh devices list and information about them (to access them use
     /// `device_list()` method)
+    /// Identical to `reset_devices()` followed by `add_devices(0, 0)`.
     pub fn refresh_devices(&mut self) -> HidResult<()> {
-        let device_list = HidApiBackend::get_hid_device_info_vector()?;
-        self.device_list = device_list;
+        self.reset_devices()?;
+        self.add_devices(0, 0)?;
+        Ok(())
+    }
+
+    /// Reset devices list. Intended to be used with the `add_devices` method.
+    pub fn reset_devices(&mut self) -> HidResult<()> {
+        self.device_list.clear();
+        Ok(())
+    }
+
+    /// Indexes devices that match the given VID and PID filters.
+    /// 0 indicates no filter.
+    pub fn add_devices(&mut self, vid: u16, pid: u16) -> HidResult<()> {
+        self.device_list.append(&mut HidApiBackend::get_hid_device_info_vector(vid, pid)?);
         Ok(())
     }
 
-    /// Returns iterator containing information about attached HID devices.
+    /// Returns iterator containing information about attached HID devices
+    /// that have been indexed, either by `refresh_devices` or `add_devices`.
     pub fn device_list(&self) -> impl Iterator<Item = &DeviceInfo> {
         self.device_list.iter()
     }

src/linux_native.rs

@@ -33,7 +33,7 @@ const BUS_SPI: u16 = 0x1C;
 pub struct HidApiBackend;
 
 impl HidApiBackend {
-    pub fn get_hid_device_info_vector() -> HidResult<Vec<DeviceInfo>> {
+    pub fn get_hid_device_info_vector(vid: u16, pid: u16) -> HidResult<Vec<DeviceInfo>> {
         // The C version assumes these can't fail, and they should only fail in case
         // of memory allocation issues, at which point maybe we should panic
         let mut enumerator = match udev::Enumerator::new() {
@@ -49,6 +49,8 @@ impl HidApiBackend {
         let devices = scan
             .filter_map(|device| device_to_hid_device_info(&device))
             .flatten()
+            .filter(|device| vid == 0 || device.vendor_id == vid)
+            .filter(|device| pid == 0 || device.product_id == pid)
             .collect::<Vec<_>>();
 
         Ok(devices)
@@ -411,7 +413,7 @@ unsafe impl Send for HidDevice {}
 // API for the library to call us, or for internal uses
 impl HidDevice {
     pub(crate) fn open(vid: u16, pid: u16, sn: Option<&str>) -> HidResult<Self> {
-        for device in HidApiBackend::get_hid_device_info_vector()?
+        for device in HidApiBackend::get_hid_device_info_vector(0, 0)?
             .iter()
             .filter(|device| device.vendor_id == vid && device.product_id == pid)
         {

src/windows_native/mod.rs

@@ -47,8 +47,8 @@ macro_rules! ensure {
 
 pub struct HidApiBackend;
 impl HidApiBackend {
-    pub fn get_hid_device_info_vector() -> HidResult<Vec<DeviceInfo>> {
-        Ok(enumerate_devices(0, 0)?)
+    pub fn get_hid_device_info_vector(vid: u16, pid: u16) -> HidResult<Vec<DeviceInfo>> {
+        Ok(enumerate_devices(vid, pid)?)
     }
 
     pub fn open(vid: u16, pid: u16) -> HidResult<HidDevice> {