lint: Resolve the easier clippy lints

Hopefully the changes are self-explanatory and uncontroversial. This
eliminates much of the noise from `cargo clippy` and, for my purposes,
gives me a reasonable way to use it as a tool when writing and reviewing
code.

Here is the Clippy invocation I was using:

    cargo +nightly clippy -- -W clippy::correctness -A renamed_and_removed_lints -Aclippy::{blacklisted_name,borrowed_box,cast_lossless,cast_ptr_alignment,enum_variant_names,identity_op,if_same_then_else,mut_from_ref,needless_pass_by_value,new_without_default,new_without_default_derive,or_fun_call,ptr_arg,should_implement_trait,single_match,too_many_arguments,trivially_copy_pass_by_ref,unreadable_literal,unsafe_vector_initialization,useless_transmute}

TEST=cargo check --features wl-dmabuf,gpu,usb-emulation
TEST=boot linux

Change-Id: I55eb1b4a72beb2f762480e3333a921909314a0a2
Reviewed-on: https://chromium-review.googlesource.com/1356911
Commit-Ready: David Tolnay <dtolnay@chromium.org>
Tested-by: David Tolnay <dtolnay@chromium.org>
Reviewed-by: Dylan Reid <dgreid@chromium.org>

6 files changed, 23 insertions, 26 deletions

diff --git a/sys_util/src/guest_memory.rs b/sys_util/src/guest_memory.rs
index 604ef49..3622085 100644
--- a/sys_util/src/guest_memory.rs
+++ b/sys_util/src/guest_memory.rs
@@ -27,10 +27,10 @@ pub type Result<T> = result::Result<T, Error>;
 impl error::Error for Error {
     fn description(&self) -> &str {
         match self {
-            &Error::InvalidGuestAddress(_) => "Invalid Guest Address",
-            &Error::MemoryAccess(_, _) => "Invalid Guest Memory Access",
-            &Error::MemoryMappingFailed(_) => "Failed to map guest memory",
-            &Error::MemoryRegionOverlap => "Memory regions overlap",
+            Error::InvalidGuestAddress(_) => "Invalid Guest Address",
+            Error::MemoryAccess(_, _) => "Invalid Guest Memory Access",
+            Error::MemoryMappingFailed(_) => "Failed to map guest memory",
+            Error::MemoryRegionOverlap => "Memory regions overlap",
         }
     }
 }
@@ -386,7 +386,7 @@ impl GuestMemory {
         self.do_in_region(guest_addr, |mapping, offset| {
             // This is safe; `do_in_region` already checks that offset is in
             // bounds.
-            Ok(unsafe { mapping.as_ptr().offset(offset as isize) } as *const u8)
+            Ok(unsafe { mapping.as_ptr().add(offset) } as *const u8)
         })
     }
 
diff --git a/sys_util/src/handle_eintr.rs b/sys_util/src/handle_eintr.rs
index 4faab07..b570c36 100644
--- a/sys_util/src/handle_eintr.rs
+++ b/sys_util/src/handle_eintr.rs
@@ -18,7 +18,7 @@ pub trait InterruptibleResult {
 impl<T> InterruptibleResult for ::Result<T> {
     fn is_interrupted(&self) -> bool {
         match self {
-            &Err(e) if e.errno() == EINTR => true,
+            Err(e) if e.errno() == EINTR => true,
             _ => false,
         }
     }
@@ -27,7 +27,7 @@ impl<T> InterruptibleResult for ::Result<T> {
 impl<T> InterruptibleResult for io::Result<T> {
     fn is_interrupted(&self) -> bool {
         match self {
-            &Err(ref e) if e.kind() == io::ErrorKind::Interrupted => true,
+            Err(e) if e.kind() == io::ErrorKind::Interrupted => true,
             _ => false,
         }
     }
diff --git a/sys_util/src/signal.rs b/sys_util/src/signal.rs
index 69e0fd0..fe01dcf 100644
--- a/sys_util/src/signal.rs
+++ b/sys_util/src/signal.rs
@@ -124,7 +124,7 @@ pub fn get_blocked_signals() -> SignalResult<Vec<c_int>> {
             return Err(Error::RetrieveSignalMask(ret));
         }
 
-        for num in 0..(SIGRTMAX() + 1) {
+        for num in 0..=SIGRTMAX() {
             if sigismember(&old_sigset, num) > 0 {
                 mask.push(num);
             }
diff --git a/sys_util/src/sock_ctrl_msg.rs b/sys_util/src/sock_ctrl_msg.rs
index a21b64a..337dbb9 100644
--- a/sys_util/src/sock_ctrl_msg.rs
+++ b/sys_util/src/sock_ctrl_msg.rs
@@ -54,8 +54,7 @@ fn CMSG_DATA(cmsg_buffer: *mut cmsghdr) -> *mut RawFd {
 // does some pointer arithmetic on cmsg_ptr.
 #[cfg_attr(feature = "cargo-clippy", allow(cast_ptr_alignment))]
 fn get_next_cmsg(msghdr: &msghdr, cmsg: &cmsghdr, cmsg_ptr: *mut cmsghdr) -> *mut cmsghdr {
-    let next_cmsg =
-        (cmsg_ptr as *mut u8).wrapping_offset(CMSG_ALIGN!(cmsg.cmsg_len) as isize) as *mut cmsghdr;
+    let next_cmsg = (cmsg_ptr as *mut u8).wrapping_add(CMSG_ALIGN!(cmsg.cmsg_len)) as *mut cmsghdr;
     if next_cmsg
         .wrapping_offset(1)
         .wrapping_sub(msghdr.msg_control as usize) as usize
@@ -311,6 +310,8 @@ pub unsafe trait IntoIovec {
 // Safe because this slice can not have another mutable reference and it's pointer and size are
 // guaranteed to be valid.
 unsafe impl<'a> IntoIovec for &'a [u8] {
+    // Clippy false positive: https://github.com/rust-lang/rust-clippy/issues/3480
+    #[cfg_attr(feature = "cargo-clippy", allow(useless_asref))]
     fn as_ptr(&self) -> *const c_void {
         self.as_ref().as_ptr() as *const c_void
     }
diff --git a/sys_util/src/syslog.rs b/sys_util/src/syslog.rs
index c080041..be85d2b 100644
--- a/sys_util/src/syslog.rs
+++ b/sys_util/src/syslog.rs
@@ -45,7 +45,7 @@ use libc::{
 
 use getpid;
 
-const SYSLOG_PATH: &'static str = "/dev/log";
+const SYSLOG_PATH: &str = "/dev/log";
 
 /// The priority (i.e. severity) of a syslog message.
 ///
@@ -65,14 +65,14 @@ pub enum Priority {
 impl fmt::Display for Priority {
     fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
         match self {
-            &Priority::Emergency => write!(f, "EMERGENCY"),
-            &Priority::Alert => write!(f, "ALERT"),
-            &Priority::Critical => write!(f, "CRITICAL"),
-            &Priority::Error => write!(f, "ERROR"),
-            &Priority::Warning => write!(f, "WARNING"),
-            &Priority::Notice => write!(f, "NOTICE"),
-            &Priority::Info => write!(f, "INFO"),
-            &Priority::Debug => write!(f, "DEBUG"),
+            Priority::Emergency => write!(f, "EMERGENCY"),
+            Priority::Alert => write!(f, "ALERT"),
+            Priority::Critical => write!(f, "CRITICAL"),
+            Priority::Error => write!(f, "ERROR"),
+            Priority::Warning => write!(f, "WARNING"),
+            Priority::Notice => write!(f, "NOTICE"),
+            Priority::Info => write!(f, "INFO"),
+            Priority::Debug => write!(f, "DEBUG"),
         }
     }
 }
@@ -417,7 +417,7 @@ fn get_localtime() -> tm {
 /// # }
 /// ```
 pub fn log(pri: Priority, fac: Facility, file_name: &str, line: u32, args: fmt::Arguments) {
-    const MONTHS: [&'static str; 12] = [
+    const MONTHS: [&str; 12] = [
         "Jan", "Feb", "Mar", "Apr", "May", "Jun", "Jul", "Aug", "Sep", "Oct", "Nov", "Dec",
     ];
 
@@ -457,11 +457,7 @@ pub fn log(pri: Priority, fac: Facility, file_name: &str, line: u32, args: fmt::
     let (res, len) = {
         let mut buf_cursor = Cursor::new(&mut buf[..]);
         (
-            write!(
-                &mut buf_cursor,
-                "[{}:{}:{}] {}\n",
-                pri, file_name, line, args
-            ),
+            writeln!(&mut buf_cursor, "[{}:{}:{}] {}", pri, file_name, line, args),
             buf_cursor.position() as usize,
         )
     };
diff --git a/sys_util/src/tempdir.rs b/sys_util/src/tempdir.rs
index 28f61c3..755865c 100644
--- a/sys_util/src/tempdir.rs
+++ b/sys_util/src/tempdir.rs
@@ -60,7 +60,7 @@ impl TempDir {
     /// will also remove the directory.  Calling remove explicitly allows for better error handling.
     pub fn remove(mut self) -> Result<()> {
         let path = self.path.take();
-        path.map_or(Ok(()), |ref p| fs::remove_dir_all(p))?;
+        path.map_or(Ok(()), fs::remove_dir_all)?;
         Ok(())
     }