clippy: fix warnings in various modules in components (#31568)

* clippy: fix warnings in various modules in components

* fix: unit tests

* fix: build on android

* fix: all samplers use new_boxed

components/background_hang_monitor/background_hang_monitor.rs

@@ -92,19 +92,19 @@ impl BackgroundHangMonitorRegister for HangMonitorRegister {
             target_os = "windows",
             any(target_arch = "x86_64", target_arch = "x86")
         ))]
-        let sampler = crate::sampler_windows::WindowsSampler::new();
+        let sampler = crate::sampler_windows::WindowsSampler::new_boxed();
         #[cfg(target_os = "macos")]
-        let sampler = crate::sampler_mac::MacOsSampler::new();
+        let sampler = crate::sampler_mac::MacOsSampler::new_boxed();
         #[cfg(all(
             target_os = "linux",
             not(any(target_arch = "arm", target_arch = "aarch64"))
         ))]
-        let sampler = crate::sampler_linux::LinuxSampler::new();
+        let sampler = crate::sampler_linux::LinuxSampler::new_boxed();
         #[cfg(any(
             target_os = "android",
             all(target_os = "linux", any(target_arch = "arm", target_arch = "aarch64"))
         ))]
-        let sampler = crate::sampler::DummySampler::new();
+        let sampler = crate::sampler::DummySampler::new_boxed();
 
         // When a component is registered, and there's an exit request that
         // reached BHM, we want an exit signal to be delivered to the
@@ -208,7 +208,7 @@ impl BackgroundHangMonitorChan {
         BackgroundHangMonitorChan {
             sender,
             _tether: tether,
-            component_id: component_id,
+            component_id,
             disconnected: Default::default(),
             monitoring_enabled,
         }
@@ -312,14 +312,14 @@ struct BackgroundHangMonitorWorker {
     monitoring_enabled: bool,
 }
 
+type MonitoredComponentSender = Sender<(MonitoredComponentId, MonitoredComponentMsg)>;
+type MonitoredComponentReceiver = Receiver<(MonitoredComponentId, MonitoredComponentMsg)>;
+
 impl BackgroundHangMonitorWorker {
     fn new(
         constellation_chan: IpcSender<HangMonitorAlert>,
         control_port: IpcReceiver<BackgroundHangMonitorControlMsg>,
-        (port_sender, port): (
-            Arc<Sender<(MonitoredComponentId, MonitoredComponentMsg)>>,
-            Receiver<(MonitoredComponentId, MonitoredComponentMsg)>,
-        ),
+        (port_sender, port): (Arc<MonitoredComponentSender>, MonitoredComponentReceiver),
         tether_port: Receiver<Never>,
         monitoring_enabled: bool,
     ) -> Self {
@@ -360,7 +360,7 @@ impl BackgroundHangMonitorWorker {
             let profile = stack.to_hangprofile();
             let name = match self.component_names.get(&id) {
                 Some(ref s) => format!("\"{}\"", s),
-                None => format!("null"),
+                None => "null".to_string(),
             };
             let json = format!(
                 "{}{{ \"name\": {}, \"namespace\": {}, \"index\": {}, \"type\": \"{:?}\", \
@@ -389,12 +389,10 @@ impl BackgroundHangMonitorWorker {
                 .checked_sub(Instant::now() - self.last_sample)
                 .unwrap_or_else(|| Duration::from_millis(0));
             after(duration)
+        } else if self.monitoring_enabled {
+            after(Duration::from_millis(100))
         } else {
-            if self.monitoring_enabled {
-                after(Duration::from_millis(100))
-            } else {
-                never()
-            }
+            never()
         };
 
         let received = select! {
@@ -403,13 +401,8 @@ impl BackgroundHangMonitorWorker {
                 // gets disconnected.
                 Some(event.unwrap())
             },
-            recv(self.tether_port) -> event => {
+            recv(self.tether_port) -> _ => {
                 // This arm can only reached by a tether disconnection
-                match event {
-                    Ok(x) => match x {}
-                    Err(_) => {}
-                }
-
                 // All associated `HangMonitorRegister` and
                 // `BackgroundHangMonitorChan` have been dropped. Suppress
                 // `signal_to_exit` and exit the BHM.

components/background_hang_monitor/sampler.rs

@@ -4,7 +4,6 @@
 
 use std::ptr;
 
-use backtrace;
 use msg::constellation_msg::{HangProfile, HangProfileSymbol};
 
 const MAX_NATIVE_FRAMES: usize = 1024;
@@ -18,7 +17,7 @@ pub struct DummySampler;
 
 impl DummySampler {
     #[allow(dead_code)]
-    pub fn new() -> Box<dyn Sampler> {
+    pub fn new_boxed() -> Box<dyn Sampler> {
         Box::new(DummySampler)
     }
 }
@@ -64,12 +63,12 @@ impl NativeStack {
         instruction_ptr: *mut std::ffi::c_void,
         stack_ptr: *mut std::ffi::c_void,
     ) -> Result<(), ()> {
-        if !(self.count < MAX_NATIVE_FRAMES) {
+        if self.count >= MAX_NATIVE_FRAMES {
             return Err(());
         }
         self.instruction_ptrs[self.count] = instruction_ptr;
         self.stack_ptrs[self.count] = stack_ptr;
-        self.count = self.count + 1;
+        self.count += 1;
         Ok(())
     }
 
@@ -85,7 +84,7 @@ impl NativeStack {
                 // TODO: use the demangled or C++ demangled symbols if available.
                 let name = symbol
                     .name()
-                    .map(|n| String::from_utf8_lossy(&n.as_bytes()).to_string());
+                    .map(|n| String::from_utf8_lossy(n.as_bytes()).to_string());
                 let filename = symbol.filename().map(|n| n.to_string_lossy().to_string());
                 let lineno = symbol.lineno();
                 profile.backtrace.push(HangProfileSymbol {

components/background_hang_monitor/sampler_linux.rs

@@ -6,9 +6,8 @@
 
 use std::cell::UnsafeCell;
 use std::sync::atomic::{AtomicPtr, Ordering};
-use std::{io, mem, process, ptr, thread};
+use std::{cmp, io, mem, process, ptr, thread};
 
-use libc;
 use nix::sys::signal::{sigaction, SaFlags, SigAction, SigHandler, SigSet, Signal};
 use unwind_sys::{
     unw_cursor_t, unw_get_reg, unw_init_local, unw_step, UNW_ESUCCESS, UNW_REG_IP, UNW_REG_SP,
@@ -138,7 +137,7 @@ pub struct LinuxSampler {
 
 impl LinuxSampler {
     #[allow(unsafe_code, dead_code)]
-    pub fn new() -> Box<dyn Sampler> {
+    pub fn new_boxed() -> Box<dyn Sampler> {
         let thread_id = unsafe { libc::syscall(libc::SYS_gettid) as libc::pid_t };
         let handler = SigHandler::SigAction(sigprof_handler);
         let action = SigAction::new(
@@ -181,12 +180,10 @@ fn step(cursor: *mut unw_cursor_t) -> Result<bool, i32> {
         }
 
         let ret = unw_step(cursor);
-        if ret > 0 {
-            Ok(true)
-        } else if ret == 0 {
-            Ok(false)
-        } else {
-            Err(ret)
+        match ret.cmp(&0) {
+            cmp::Ordering::Less => Err(ret),
+            cmp::Ordering::Greater => Ok(true),
+            cmp::Ordering::Equal => Ok(false),
         }
     }
 }
@@ -222,6 +219,7 @@ impl Sampler for LinuxSampler {
             let ret = unsafe { unw_init_local(cursor.as_mut_ptr(), context) };
             result = if ret == UNW_ESUCCESS {
                 let mut native_stack = NativeStack::new();
+                #[allow(clippy::while_let_loop)] // False positive
                 loop {
                     let ip = match get_register(cursor.as_mut_ptr(), RegNum::Ip) {
                         Ok(ip) => ip,

components/background_hang_monitor/sampler_mac.rs

@@ -16,7 +16,7 @@ pub struct MacOsSampler {
 
 impl MacOsSampler {
     #[allow(unsafe_code)]
-    pub fn new() -> Box<dyn Sampler> {
+    pub fn new_boxed() -> Box<dyn Sampler> {
         let thread_id = unsafe { mach2::mach_init::mach_thread_self() };
         Box::new(MacOsSampler { thread_id })
     }

components/background_hang_monitor/sampler_windows.rs

@@ -13,7 +13,7 @@ pub struct WindowsSampler {
 
 impl WindowsSampler {
     #[allow(unsafe_code, dead_code)]
-    pub fn new() -> Box<dyn Sampler> {
+    pub fn new_boxed() -> Box<dyn Sampler> {
         let thread_id = 0; // TODO: use winapi::um::processthreadsapi::GetThreadId
         Box::new(WindowsSampler { thread_id })
     }