uefi: simplify return type of memory_map

Author: phip1611

CHANGELOG.md

@@ -23,6 +23,10 @@
 - `UnalignedSlice` now implements `Clone`, and the `Debug` impl now
   prints the elements instead of the internal fields.
 - The unstable `negative_impls` feature is no longer required to use this library.
+- `BootServices::memory_map()` now returns `MemoryMapIter` instead of
+  `impl Iterator` which simplifies usage.
+- `BootServices::exit_boot_services()` now returns `MemoryMapIter` instead of
+  `impl Iterator` which simplifies usage.
 
 ### Removed
 

uefi/src/table/boot.rs

@@ -424,10 +424,7 @@ impl BootServices {
     pub fn memory_map<'buf>(
         &self,
         buffer: &'buf mut [u8],
-    ) -> Result<(
-        MemoryMapKey,
-        impl ExactSizeIterator<Item = &'buf MemoryDescriptor> + Clone,
-    )> {
+    ) -> Result<(MemoryMapKey, MemoryMapIter<'buf>)> {
         let mut map_size = buffer.len();
         MemoryDescriptor::assert_aligned(buffer);
         let map_buffer = buffer.as_mut_ptr().cast::<MemoryDescriptor>();
@@ -2077,9 +2074,10 @@ pub struct MemoryMapSize {
     pub map_size: usize,
 }
 
-/// An iterator of memory descriptors
+/// An iterator of [`MemoryDescriptor`]. The underlying memory map is always
+/// associated with a unique [`MemoryMapKey`].
 #[derive(Debug, Clone)]
-struct MemoryMapIter<'buf> {
+pub struct MemoryMapIter<'buf> {
     buffer: &'buf [u8],
     entry_size: usize,
     index: usize,

uefi/src/table/system.rs

@@ -7,7 +7,7 @@ use core::{ptr, slice};
 use crate::proto::console::text;
 use crate::{CStr16, Char16, Handle, Result, ResultExt, Status};
 
-use super::boot::{BootServices, MemoryDescriptor};
+use super::boot::{BootServices, MemoryDescriptor, MemoryMapIter};
 use super::runtime::RuntimeServices;
 use super::{cfg, Header, Revision};
 
@@ -182,10 +182,7 @@ impl SystemTable<Boot> {
         self,
         image: Handle,
         mmap_buf: &mut [u8],
-    ) -> Result<(
-        SystemTable<Runtime>,
-        impl ExactSizeIterator<Item = &MemoryDescriptor> + Clone,
-    )> {
+    ) -> Result<(SystemTable<Runtime>, MemoryMapIter<'_>)> {
         unsafe {
             let boot_services = self.boot_services();