Replace some Option<u8> to Option<NonZeroU8>

manufacturer_string_index serial_number_string_index product_string_index description_string_index ref #88
a1ien · Jul 27, 2021 · 6b15215 · 6b15215
1 parent 009254b
commit 6b15215
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Showing 5 changed files with 58 additions and 47 deletions.
diff --git a/examples/list_devices.rs b/examples/list_devices.rs
@@ -2,6 +2,7 @@ use rusb::{
     ConfigDescriptor, DeviceDescriptor, DeviceHandle, DeviceList, EndpointDescriptor,
     InterfaceDescriptor, Language, Result, Speed, UsbContext,
 };
+use std::num::NonZeroU8;
 use std::time::Duration;
 
 struct UsbDevice<T: UsbContext> {
@@ -101,23 +102,27 @@ fn print_device<T: UsbContext>(device_desc: &DeviceDescriptor, handle: &mut Opti
     );
     println!(
         "  iManufacturer        {:3} {}",
-        device_desc.manufacturer_string_index().unwrap_or(0),
+        device_desc
+            .manufacturer_string_index()
+            .map_or(0, NonZeroU8::get),
         handle.as_mut().map_or(String::new(), |h| h
             .handle
             .read_manufacturer_string(h.language, device_desc, h.timeout)
             .unwrap_or(String::new()))
     );
     println!(
         "  iProduct             {:3} {}",
-        device_desc.product_string_index().unwrap_or(0),
+        device_desc.product_string_index().map_or(0, NonZeroU8::get),
         handle.as_mut().map_or(String::new(), |h| h
             .handle
             .read_product_string(h.language, device_desc, h.timeout)
             .unwrap_or(String::new()))
     );
     println!(
         "  iSerialNumber        {:3} {}",
-        device_desc.serial_number_string_index().unwrap_or(0),
+        device_desc
+            .serial_number_string_index()
+            .map_or(0, NonZeroU8::get),
         handle.as_mut().map_or(String::new(), |h| h
             .handle
             .read_serial_number_string(h.language, device_desc, h.timeout)
@@ -138,7 +143,9 @@ fn print_config<T: UsbContext>(config_desc: &ConfigDescriptor, handle: &mut Opti
     println!("    bConfigurationValue  {:3}", config_desc.number());
     println!(
         "    iConfiguration       {:3} {}",
-        config_desc.description_string_index().unwrap_or(0),
+        config_desc
+            .description_string_index()
+            .map_or(0, NonZeroU8::get),
         handle.as_mut().map_or(String::new(), |h| h
             .handle
             .read_configuration_string(h.language, config_desc, h.timeout)
@@ -187,7 +194,9 @@ fn print_interface<T: UsbContext>(
     );
     println!(
         "      iInterface           {:3} {}",
-        interface_desc.description_string_index().unwrap_or(0),
+        interface_desc
+            .description_string_index()
+            .map_or(0, NonZeroU8::get),
         handle.as_mut().map_or(String::new(), |h| h
             .handle
             .read_interface_string(h.language, interface_desc, h.timeout)

diff --git a/src/config_descriptor.rs b/src/config_descriptor.rs
@@ -3,6 +3,7 @@ use std::{fmt, slice};
 use libusb1_sys::*;
 
 use crate::interface_descriptor::{self, Interface};
+use std::num::NonZeroU8;
 
 /// Describes a configuration.
 pub struct ConfigDescriptor {
@@ -42,13 +43,8 @@ impl ConfigDescriptor {
     }
 
     /// Returns the index of the string descriptor that describes the configuration.
-    pub fn description_string_index(&self) -> Option<u8> {
-        unsafe {
-            match (*self.descriptor).iConfiguration {
-                0 => None,
-                n => Some(n),
-            }
-        }
+    pub fn description_string_index(&self) -> Option<NonZeroU8> {
+        NonZeroU8::new(unsafe { (*self.descriptor).iConfiguration })
     }
 
     /// Returns the number of interfaces for this configuration.
@@ -130,6 +126,7 @@ pub(crate) unsafe fn from_libusb(config: *const libusb_config_descriptor) -> Con
 
 #[cfg(test)]
 mod test {
+    use super::*;
     use std::mem;
 
     // The Drop trait impl calls libusb_free_config_descriptor(), which would attempt to free
@@ -185,7 +182,7 @@ mod test {
     #[test]
     fn it_has_description_string_index() {
         with_config!(config: config_descriptor!(iConfiguration: 42) => {
-            assert_eq!(Some(42), config.description_string_index());
+            assert_eq!(Some(42), config.description_string_index().map(NonZeroU8::get));
         });
     }
 

diff --git a/src/device_descriptor.rs b/src/device_descriptor.rs
@@ -3,6 +3,7 @@ use std::fmt;
 use libusb1_sys::*;
 
 use crate::fields::Version;
+use std::num::NonZeroU8;
 
 /// Describes a device.
 pub struct DeviceDescriptor {
@@ -21,27 +22,18 @@ impl DeviceDescriptor {
     }
 
     /// Returns the index of the string descriptor that contains the manufacturer name.
-    pub fn manufacturer_string_index(&self) -> Option<u8> {
-        match self.descriptor.iManufacturer {
-            0 => None,
-            n => Some(n),
-        }
+    pub fn manufacturer_string_index(&self) -> Option<NonZeroU8> {
+        NonZeroU8::new(self.descriptor.iManufacturer)
     }
 
     /// Returns the index of the string descriptor that contains the product name.
-    pub fn product_string_index(&self) -> Option<u8> {
-        match self.descriptor.iProduct {
-            0 => None,
-            n => Some(n),
-        }
+    pub fn product_string_index(&self) -> Option<NonZeroU8> {
+        NonZeroU8::new(self.descriptor.iProduct)
     }
 
     /// Returns the index of the string descriptor that contains the device's serial number.
-    pub fn serial_number_string_index(&self) -> Option<u8> {
-        match self.descriptor.iSerialNumber {
-            0 => None,
-            n => Some(n),
-        }
+    pub fn serial_number_string_index(&self) -> Option<NonZeroU8> {
+        NonZeroU8::new(self.descriptor.iSerialNumber)
     }
 
     /// Returns the device's class code.
@@ -110,13 +102,14 @@ pub fn from_libusb(device: libusb_device_descriptor) -> DeviceDescriptor {
 
 #[cfg(test)]
 mod test {
+    use super::*;
     use crate::fields::Version;
 
     #[test]
     fn it_has_usb_version() {
         assert_eq!(
             Version::from_bcd(0x1234),
-            super::from_libusb(device_descriptor!(bcdUSB: 0x1234)).usb_version()
+            from_libusb(device_descriptor!(bcdUSB: 0x1234)).usb_version()
         );
     }
 
@@ -132,7 +125,9 @@ mod test {
     fn it_has_manufacturer_string_index() {
         assert_eq!(
             Some(42),
-            super::from_libusb(device_descriptor!(iManufacturer: 42)).manufacturer_string_index()
+            from_libusb(device_descriptor!(iManufacturer: 42))
+                .manufacturer_string_index()
+                .map(NonZeroU8::get)
         );
     }
 
@@ -148,7 +143,9 @@ mod test {
     fn it_has_product_string_index() {
         assert_eq!(
             Some(42),
-            super::from_libusb(device_descriptor!(iProduct: 42)).product_string_index()
+            super::from_libusb(device_descriptor!(iProduct: 42))
+                .product_string_index()
+                .map(NonZeroU8::get)
         );
     }
 
@@ -164,7 +161,9 @@ mod test {
     fn it_has_serial_number_string_index() {
         assert_eq!(
             Some(42),
-            super::from_libusb(device_descriptor!(iSerialNumber: 42)).serial_number_string_index()
+            super::from_libusb(device_descriptor!(iSerialNumber: 42))
+                .serial_number_string_index()
+                .map(NonZeroU8::get)
         );
     }
 

diff --git a/src/device_handle.rs b/src/device_handle.rs
@@ -1,4 +1,10 @@
-use std::{mem, fmt::{self, Debug}, ptr::NonNull, time::Duration, u8};
+use std::{
+    fmt::{self, Debug},
+    mem,
+    ptr::NonNull,
+    time::Duration,
+    u8,
+};
 
 use libc::{c_int, c_uchar, c_uint};
 use libusb1_sys::{constants::*, *};
@@ -726,7 +732,7 @@ impl<T: UsbContext> DeviceHandle<T> {
     ) -> crate::Result<String> {
         match device.manufacturer_string_index() {
             None => Err(Error::InvalidParam),
-            Some(n) => self.read_string_descriptor_ascii(n),
+            Some(n) => self.read_string_descriptor_ascii(n.get()),
         }
     }
 
@@ -739,15 +745,15 @@ impl<T: UsbContext> DeviceHandle<T> {
     ) -> crate::Result<String> {
         match device.manufacturer_string_index() {
             None => Err(Error::InvalidParam),
-            Some(n) => self.read_string_descriptor(language, n, timeout),
+            Some(n) => self.read_string_descriptor(language, n.get(), timeout),
         }
     }
 
     /// Reads the device's product string descriptor (ascii).
     pub fn read_product_string_ascii(&self, device: &DeviceDescriptor) -> crate::Result<String> {
         match device.product_string_index() {
             None => Err(Error::InvalidParam),
-            Some(n) => self.read_string_descriptor_ascii(n),
+            Some(n) => self.read_string_descriptor_ascii(n.get()),
         }
     }
 
@@ -760,7 +766,7 @@ impl<T: UsbContext> DeviceHandle<T> {
     ) -> crate::Result<String> {
         match device.product_string_index() {
             None => Err(Error::InvalidParam),
-            Some(n) => self.read_string_descriptor(language, n, timeout),
+            Some(n) => self.read_string_descriptor(language, n.get(), timeout),
         }
     }
 
@@ -771,7 +777,7 @@ impl<T: UsbContext> DeviceHandle<T> {
     ) -> crate::Result<String> {
         match device.serial_number_string_index() {
             None => Err(Error::InvalidParam),
-            Some(n) => self.read_string_descriptor_ascii(n),
+            Some(n) => self.read_string_descriptor_ascii(n.get()),
         }
     }
 
@@ -784,7 +790,7 @@ impl<T: UsbContext> DeviceHandle<T> {
     ) -> crate::Result<String> {
         match device.serial_number_string_index() {
             None => Err(Error::InvalidParam),
-            Some(n) => self.read_string_descriptor(language, n, timeout),
+            Some(n) => self.read_string_descriptor(language, n.get(), timeout),
         }
     }
 
@@ -797,7 +803,7 @@ impl<T: UsbContext> DeviceHandle<T> {
     ) -> crate::Result<String> {
         match configuration.description_string_index() {
             None => Err(Error::InvalidParam),
-            Some(n) => self.read_string_descriptor(language, n, timeout),
+            Some(n) => self.read_string_descriptor(language, n.get(), timeout),
         }
     }
 
@@ -810,7 +816,7 @@ impl<T: UsbContext> DeviceHandle<T> {
     ) -> crate::Result<String> {
         match interface.description_string_index() {
             None => Err(Error::InvalidParam),
-            Some(n) => self.read_string_descriptor(language, n, timeout),
+            Some(n) => self.read_string_descriptor(language, n.get(), timeout),
         }
     }
 }

diff --git a/src/interface_descriptor.rs b/src/interface_descriptor.rs
@@ -3,6 +3,7 @@ use std::{fmt, slice};
 use libusb1_sys::{libusb_endpoint_descriptor, libusb_interface, libusb_interface_descriptor};
 
 use crate::endpoint_descriptor::{self, EndpointDescriptor};
+use std::num::NonZeroU8;
 
 /// A device interface.
 ///
@@ -77,11 +78,8 @@ impl<'a> InterfaceDescriptor<'a> {
     }
 
     /// Returns the index of the string descriptor that describes the interface.
-    pub fn description_string_index(&self) -> Option<u8> {
-        match self.descriptor.iInterface {
-            0 => None,
-            n => Some(n),
-        }
+    pub fn description_string_index(&self) -> Option<NonZeroU8> {
+        NonZeroU8::new(self.descriptor.iInterface)
     }
 
     /// Returns the number of endpoints belonging to this interface.
@@ -165,6 +163,8 @@ pub(crate) unsafe fn from_libusb(interface: &libusb_interface) -> Interface {
 
 #[cfg(test)]
 mod test {
+    use super::*;
+
     #[test]
     fn it_has_interface_number() {
         assert_eq!(
@@ -241,7 +241,7 @@ mod test {
             vec!(Some(42)),
             unsafe { super::from_libusb(&interface!(interface_descriptor!(iInterface: 42))) }
                 .descriptors()
-                .map(|setting| setting.description_string_index())
+                .map(|setting| setting.description_string_index().map(NonZeroU8::get))
                 .collect::<Vec<_>>()
         );
     }