file: remove more implicit string conversions

The file info types are now constructed directly from a `&CStr16`
instead of internally converting from a `&str`.

rust-osdev#73

src/proto/media/file/info.rs

@@ -2,7 +2,6 @@ use super::FileAttribute;
 use crate::data_types::{chars::NUL_16, Align};
 use crate::table::runtime::Time;
 use crate::{unsafe_guid, CStr16, Char16, Identify};
-use core::convert::TryInto;
 use core::ffi::c_void;
 use core::{cmp, mem, ptr};
 
@@ -50,9 +49,8 @@ impl<Header> NamedFileProtocolInfo<Header> {
     ///
     /// The structure will be created in-place within the provided storage
     /// buffer. The buffer must be large enough to hold the data structure,
-    /// including a null-terminated UCS-2 version of the `name` string. Note
-    /// that the struct's aligned size might require additional space beyond
-    /// the header and name.
+    /// including a null-terminated UCS-2 `name` string. Note that the struct's
+    /// aligned size might require additional space beyond the header and name.
     ///
     /// The buffer must be correctly aligned. You can query the required
     /// alignment using the `alignment()` method of the `Align` trait that this
@@ -61,16 +59,16 @@ impl<Header> NamedFileProtocolInfo<Header> {
     fn new_impl<'buf>(
         storage: &'buf mut [u8],
         header: Header,
-        name: &str,
+        name: &CStr16,
     ) -> core::result::Result<&'buf mut Self, FileInfoCreationError> {
         // Make sure that the storage is properly aligned
         Self::assert_aligned(storage);
 
         // Make sure that the storage is large enough for our needs
-        let name_length_ucs2 = name.chars().count() + 1;
-        let name_size = name_length_ucs2 * mem::size_of::<Char16>();
+        let name_num_chars = name.as_slice().len();
+        let name_num_bytes = name.num_bytes();
         // Round up the size of the header and the name to match the alignment.
-        let info_size = Self::align_size(mem::size_of::<Header>() + name_size);
+        let info_size = Self::align_size(mem::size_of::<Header>() + name_num_bytes);
         if storage.len() < info_size {
             return Err(FileInfoCreationError::InsufficientStorage(info_size));
         }
@@ -95,18 +93,14 @@ impl<Header> NamedFileProtocolInfo<Header> {
             // For more details of wide pointers, see
             // https://doc.rust-lang.org/nightly/core/ptr/trait.Pointee.html
             let fat_ptr =
-                ptr::from_raw_parts_mut::<Self>(storage.as_mut_ptr() as *mut (), name_length_ucs2);
+                ptr::from_raw_parts_mut::<Self>(storage.as_mut_ptr() as *mut (), name_num_chars);
             &mut *fat_ptr
         };
-        debug_assert_eq!(info.name.len(), name_length_ucs2);
+        debug_assert_eq!(info.name.len(), name_num_chars);
 
         // Write down the UCS-2 name before returning the storage reference
-        for (target, ch) in info.name.iter_mut().zip(name.chars()) {
-            *target = ch
-                .try_into()
-                .map_err(|_| FileInfoCreationError::InvalidChar(ch))?;
-        }
-        info.name[name_length_ucs2 - 1] = NUL_16;
+        info.name.copy_from_slice(name.as_slice());
+        debug_assert_eq!(info.name[name_num_chars - 1], NUL_16);
         Ok(info)
     }
 }
@@ -136,9 +130,6 @@ pub enum FileInfoCreationError {
     /// least the indicated buffer size (in bytes). Please remember that using
     /// a misaligned buffer will cause a decrease of usable storage capacity.
     InsufficientStorage(usize),
-
-    /// The suggested file name contains invalid code points (not in UCS-2)
-    InvalidChar(char),
 }
 
 /// Generic file information
@@ -179,9 +170,8 @@ impl FileInfo {
     ///
     /// The structure will be created in-place within the provided storage
     /// buffer. The buffer must be large enough to hold the data structure,
-    /// including a null-terminated UCS-2 version of the `name` string. Note
-    /// that the struct's aligned size might require additional space beyond
-    /// the header and name.
+    /// including a null-terminated UCS-2 `name` string. Note that the struct's
+    /// aligned size might require additional space beyond the header and name.
     ///
     /// The buffer must be correctly aligned. You can query the required
     /// alignment using the `alignment()` method of the `Align` trait that this
@@ -195,7 +185,7 @@ impl FileInfo {
         last_access_time: Time,
         modification_time: Time,
         attribute: FileAttribute,
-        file_name: &str,
+        file_name: &CStr16,
     ) -> core::result::Result<&'buf mut Self, FileInfoCreationError> {
         let header = FileInfoHeader {
             size: 0,
@@ -274,9 +264,8 @@ impl FileSystemInfo {
     ///
     /// The structure will be created in-place within the provided storage
     /// buffer. The buffer must be large enough to hold the data structure,
-    /// including a null-terminated UCS-2 version of the `name` string. Note
-    /// that the struct's aligned size might require additional space beyond
-    /// the header and name.
+    /// including a null-terminated UCS-2 `name` string. Note that the struct's
+    /// aligned size might require additional space beyond the header and name.
     ///
     /// The buffer must be correctly aligned. You can query the required
     /// alignment using the `alignment()` method of the `Align` trait that this
@@ -288,7 +277,7 @@ impl FileSystemInfo {
         volume_size: u64,
         free_space: u64,
         block_size: u32,
-        volume_label: &str,
+        volume_label: &CStr16,
     ) -> core::result::Result<&'buf mut Self, FileInfoCreationError> {
         let header = FileSystemInfoHeader {
             size: 0,
@@ -346,16 +335,15 @@ impl FileSystemVolumeLabel {
     ///
     /// The structure will be created in-place within the provided storage
     /// buffer. The buffer must be large enough to hold the data structure,
-    /// including a null-terminated UCS-2 version of the `name` string. Note
-    /// that the struct's aligned size might require additional space beyond
-    /// the header and name.
+    /// including a null-terminated UCS-2 `name` string. Note that the struct's
+    /// aligned size might require additional space beyond the header and name.
     ///
     /// The buffer must be correctly aligned. You can query the required
     /// alignment using the `alignment()` method of the `Align` trait that this
     /// struct implements.
     pub fn new<'buf>(
         storage: &'buf mut [u8],
-        volume_label: &str,
+        volume_label: &CStr16,
     ) -> core::result::Result<&'buf mut Self, FileInfoCreationError> {
         let header = FileSystemVolumeLabelHeader {};
         Self::new_impl(storage, header, volume_label)