zero copy static RO files

hyperion-os · Dec 23, 2023 · 69e2ade · 69e2ade
1 parent 3ef4bfe
commit 69e2ade
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Showing 2 changed files with 38 additions and 15 deletions.
diff --git a/crates/kshell/src/lib.rs b/crates/kshell/src/lib.rs
@@ -13,7 +13,7 @@ use hyperion_futures::keyboard::KeyboardEvents;
 use hyperion_kernel_impl::VFS_ROOT;
 use hyperion_log::*;
 use hyperion_scheduler::lock::Mutex;
-use hyperion_vfs::{error::IoError, path::PathBuf, ramdisk};
+use hyperion_vfs::{error::IoError, path::PathBuf, ramdisk::StaticRoFile};
 use snafu::Snafu;
 
 use self::{shell::Shell, term::Term};
@@ -53,18 +53,14 @@ pub async fn kshell() {
 
     for asset in ASSETS {
         let (path, bytes): (&str, &[u8]) = *asset;
-        // TODO: no copy
-        VFS_ROOT.install_dev(path, ramdisk::File::new(bytes.into()));
+        VFS_ROOT.install_dev(path, StaticRoFile::new(bytes));
     }
 
-    let bin = load_elf!("SAMPLE_ELF").into();
-    VFS_ROOT.install_dev("/bin/run", ramdisk::File::new(bin));
-    let bin = load_elf!("FBTEST").into();
-    VFS_ROOT.install_dev("/bin/fbtest", ramdisk::File::new(bin));
+    VFS_ROOT.install_dev("/bin/run", StaticRoFile::new(load_elf!("SAMPLE_ELF")));
+    VFS_ROOT.install_dev("/bin/fbtest", StaticRoFile::new(load_elf!("FBTEST")));
 
     // everything is the same file
-    let bin = load_elf!("COREUTILS").into();
-    let bin = Arc::new(Mutex::new(ramdisk::File::new(bin)));
+    let bin = Arc::new(Mutex::new(StaticRoFile::new(load_elf!("COREUTILS"))));
     VFS_ROOT.install_dev_ref("/bin/coreutils", bin.clone());
     VFS_ROOT.install_dev_ref("/bin/cat", bin.clone());
     VFS_ROOT.install_dev_ref("/bin/ls", bin.clone());

diff --git a/crates/vfs/src/ramdisk.rs b/crates/vfs/src/ramdisk.rs
@@ -3,6 +3,7 @@ use alloc::{
     sync::Arc,
     vec::Vec,
 };
+use core::any::Any;
 
 use lock_api::Mutex;
 
@@ -23,6 +24,20 @@ impl File {
     pub fn new(bytes: Vec<u8>) -> Self {
         Self { bytes }
     }
+
+    pub fn new_empty<Mut: AnyMutex>() -> FileRef<Mut> {
+        Arc::new(Mutex::new(Self { bytes: Vec::new() })) as _
+    }
+}
+
+pub struct StaticRoFile {
+    bytes: &'static [u8],
+}
+
+impl StaticRoFile {
+    pub const fn new(bytes: &'static [u8]) -> Self {
+        Self { bytes }
+    }
 }
 
 pub struct Directory<Mut: AnyMutex> {
@@ -36,7 +51,7 @@ pub struct Directory<Mut: AnyMutex> {
 //
 
 impl FileDevice for File {
-    fn as_any(&self) -> &dyn core::any::Any {
+    fn as_any(&self) -> &dyn Any {
         self
     }
 
@@ -45,19 +60,31 @@ impl FileDevice for File {
     }
 
     fn read(&self, offset: usize, buf: &mut [u8]) -> IoResult<usize> {
-        FileDevice::read(&self.bytes[..], offset, buf)
+        self.bytes.read(offset, buf)
     }
 
     fn write(&mut self, offset: usize, buf: &[u8]) -> IoResult<usize> {
         self.bytes
             .resize(self.bytes.len().max(buf.len() + offset), b'?');
-        FileDevice::write(&mut self.bytes[..], offset, buf)
+        self.bytes.write(offset, buf)
     }
 }
 
-impl File {
-    pub fn new_empty<Mut: AnyMutex>() -> FileRef<Mut> {
-        Arc::new(Mutex::new(Self { bytes: Vec::new() })) as _
+impl FileDevice for StaticRoFile {
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    fn len(&self) -> usize {
+        self.bytes.len()
+    }
+
+    fn read(&self, offset: usize, buf: &mut [u8]) -> IoResult<usize> {
+        self.bytes.read(offset, buf)
+    }
+
+    fn write(&mut self, _: usize, _: &[u8]) -> IoResult<usize> {
+        Err(IoError::PermissionDenied)
     }
 }