uefi: remove code duplication + fix import style

1. Remove code duplication by moving functionality to
   a dedicated function.
2. Typically, we first have public uses and then private
   ones.

Author: phip1611

uefi/src/boot.rs

@@ -2,24 +2,23 @@
 //!
 //! These functions will panic if called after exiting boot services.
 
+pub use crate::table::boot::{
+    AllocateType, EventNotifyFn, LoadImageSource, OpenProtocolAttributes, OpenProtocolParams,
+    SearchType, TimerTrigger,
+};
+pub use uefi_raw::table::boot::{EventType, MemoryType, Tpl};
+
 use crate::data_types::PhysicalAddress;
 use crate::proto::device_path::DevicePath;
 use crate::proto::{Protocol, ProtocolPointer};
 use crate::util::opt_nonnull_to_ptr;
+use crate::{table, Char16, Error, Event, Guid, Handle, Result, Status, StatusExt};
 use core::ffi::c_void;
 use core::ops::{Deref, DerefMut};
 use core::ptr::{self, NonNull};
 use core::sync::atomic::{AtomicPtr, Ordering};
 use core::{mem, slice};
-use uefi::{table, Char16, Error, Event, Guid, Handle, Result, Status, StatusExt};
 use uefi_raw::table::boot::InterfaceType;
-
-use crate::proto::BootPolicy;
-pub use crate::table::boot::{
-    AllocateType, EventNotifyFn, LoadImageSource, OpenProtocolAttributes, OpenProtocolParams,
-    SearchType, TimerTrigger,
-};
-pub use uefi_raw::table::boot::{EventType, MemoryType, Tpl};
 #[cfg(doc)]
 use {
     crate::proto::device_path::LoadedImageDevicePath, crate::proto::loaded_image::LoadedImage,
@@ -674,29 +673,7 @@ pub fn load_image(parent_image_handle: Handle, source: LoadImageSource) -> Resul
     let bt = boot_services_raw_panicking();
     let bt = unsafe { bt.as_ref() };
 
-    let boot_policy;
-    let device_path;
-    let source_buffer;
-    let source_size;
-    match source {
-        LoadImageSource::FromBuffer { buffer, file_path } => {
-            // Boot policy is ignored when loading from source buffer.
-            boot_policy = BootPolicy::FALSE;
-
-            device_path = file_path.map(|p| p.as_ffi_ptr()).unwrap_or(ptr::null());
-            source_buffer = buffer.as_ptr();
-            source_size = buffer.len();
-        }
-        LoadImageSource::FromDevicePath {
-            device_path: file_path,
-            bool_policy,
-        } => {
-            boot_policy = bool_policy;
-            device_path = file_path.as_ffi_ptr();
-            source_buffer = ptr::null();
-            source_size = 0;
-        }
-    };
+    let (boot_policy, device_path, source_buffer, source_size) = source.to_ffi_params();
 
     let mut image_handle = ptr::null_mut();
     unsafe {

uefi/src/table/boot.rs

@@ -22,6 +22,7 @@ use core::mem::{self, MaybeUninit};
 use core::ops::{Deref, DerefMut};
 use core::ptr::NonNull;
 use core::{ptr, slice};
+use uefi::proto::device_path::FfiDevicePath;
 
 /// Size in bytes of a UEFI page.
 ///
@@ -841,29 +842,7 @@ impl BootServices {
         parent_image_handle: Handle,
         source: LoadImageSource,
     ) -> uefi::Result<Handle> {
-        let boot_policy;
-        let device_path;
-        let source_buffer;
-        let source_size;
-        match source {
-            LoadImageSource::FromBuffer { buffer, file_path } => {
-                // Boot policy is ignored when loading from source buffer.
-                boot_policy = BootPolicy::FALSE;
-
-                device_path = file_path.map(|p| p.as_ffi_ptr()).unwrap_or(ptr::null());
-                source_buffer = buffer.as_ptr();
-                source_size = buffer.len();
-            }
-            LoadImageSource::FromDevicePath {
-                device_path: file_path,
-                bool_policy,
-            } => {
-                boot_policy = bool_policy;
-                device_path = file_path.as_ffi_ptr();
-                source_buffer = ptr::null();
-                source_size = 0;
-            }
-        };
+        let (boot_policy, device_path, source_buffer, source_size) = source.to_ffi_params();
 
         let mut image_handle = ptr::null_mut();
         unsafe {
@@ -1424,6 +1403,44 @@ pub enum LoadImageSource<'a> {
     },
 }
 
+impl<'a> LoadImageSource<'a> {
+    /// Returns the raw FFI parameters for `load_image`.
+    #[must_use]
+    pub(crate) fn to_ffi_params(
+        &self,
+    ) -> (
+        BootPolicy,
+        *const FfiDevicePath,
+        *const u8, /* buffer */
+        usize,     /* buffer length */
+    ) {
+        let boot_policy;
+        let device_path;
+        let source_buffer;
+        let source_size;
+        match self {
+            LoadImageSource::FromBuffer { buffer, file_path } => {
+                // Boot policy is ignored when loading from source buffer.
+                boot_policy = BootPolicy::FALSE;
+
+                device_path = file_path.map(|p| p.as_ffi_ptr()).unwrap_or(ptr::null());
+                source_buffer = buffer.as_ptr();
+                source_size = buffer.len();
+            }
+            LoadImageSource::FromDevicePath {
+                device_path: file_path,
+                bool_policy,
+            } => {
+                boot_policy = *bool_policy;
+                device_path = file_path.as_ffi_ptr();
+                source_buffer = ptr::null();
+                source_size = 0;
+            }
+        };
+        (boot_policy, device_path, source_buffer, source_size)
+    }
+}
+
 /// RAII guard for task priority level changes
 ///
 /// Will automatically restore the former task priority level when dropped.