Fix compilation for 32-bit architectures

Signed-off-by: Manos Pitsidianakis <manos@pitsidianak.is>

melib/src/gpgme/io.rs

@@ -224,13 +224,24 @@ impl Seek for Data {
     #[inline]
     fn seek(&mut self, pos: io::SeekFrom) -> io::Result<u64> {
         let (off, whence) = match pos {
-            io::SeekFrom::Start(off) => (off.try_into().unwrap_or(i64::MAX), libc::SEEK_SET),
+            io::SeekFrom::Start(off) => (
+                off.try_into()
+                    .map_err(|_| io::Error::from_raw_os_error(libc::EOVERFLOW))?,
+                libc::SEEK_SET,
+            ),
             io::SeekFrom::End(off) => (off.saturating_abs(), libc::SEEK_END),
             io::SeekFrom::Current(off) => (off, libc::SEEK_CUR),
         };
-        let result = unsafe { call!(self.lib, gpgme_data_seek)(self.inner.as_ptr(), off, whence) };
+        let result = unsafe {
+            call!(self.lib, gpgme_data_seek)(
+                self.inner.as_ptr(),
+                libc::off_t::try_from(off)
+                    .map_err(|_| io::Error::from_raw_os_error(libc::EOVERFLOW))?,
+                whence,
+            )
+        };
         if result >= 0 {
-            Ok(result as u64)
+            Ok(u64::try_from(result).map_err(|_| io::Error::from_raw_os_error(libc::EOVERFLOW))?)
         } else {
             Err(io::Error::last_os_error())
         }

melib/src/notmuch/mod.rs

@@ -111,12 +111,14 @@ pub struct DbConnection {
 
 impl DbConnection {
     pub fn get_revision_uuid(&self) -> u64 {
-        unsafe {
+        let ret: ::std::os::raw::c_ulong = unsafe {
             call!(self.lib, notmuch_database_get_revision)(
                 self.inner.lock().unwrap().as_mut(),
                 std::ptr::null_mut(),
             )
-        }
+        };
+        #[allow(clippy::useless_conversion)]
+        u64::from(ret)
     }
 
     #[allow(clippy::too_many_arguments)] // Don't judge me clippy.

melib/src/utils/datetime.rs

@@ -207,7 +207,7 @@ fn timestamp_to_string_inner(
 ) -> String {
     let mut new_tm: libc::tm = unsafe { std::mem::zeroed() };
     unsafe {
-        let i: i64 = timestamp.try_into().unwrap_or(0);
+        let i = timestamp.try_into().unwrap_or(0);
         if local {
             localtime_r(std::ptr::addr_of!(i), std::ptr::addr_of_mut!(new_tm));
         } else {

melib/src/utils/shellexpand.rs

@@ -261,7 +261,7 @@ pub mod impls {
         let mut buf: Vec<u8> = vec![0; BUF_SIZE * std::mem::size_of::<::libc::dirent64>()];
         let mut entries = Vec::new();
         loop {
-            let n: i64 = unsafe {
+            let n = unsafe {
                 ::libc::syscall(
                     ::libc::SYS_getdents64,
                     dir.as_raw_fd(),