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Use DiskFile in read_cb

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This will allow passing in other data sources for the qcow read methods,
without adding extra copies.

TEST=Unit tests
BUG=b:140069322
Change-Id: I2815fa6e416b554968b97959e4b6cd4c93a722f6
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/crosvm/+/1982829
Reviewed-by: Daniel Verkamp <dverkamp@chromium.org>
Tested-by: kokoro <noreply+kokoro@google.com>
Commit-Queue: Cody Schuffelen <schuffelen@google.com>
This commit is contained in:
A. Cody Schuffelen 2019-12-23 18:51:40 -08:00 committed by Commit Bot
parent e99b6c7e81
commit e058314700
1 changed files with 36 additions and 32 deletions
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68
disk/src/qcow/mod.rs
View file

@ -24,7 +24,7 @@ use std::os::unix::io::{AsRawFd, RawFd};
use crate::qcow::qcow_raw_file::QcowRawFile;
use crate::qcow::refcount::RefCount;
use crate::qcow::vec_cache::{CacheMap, Cacheable, VecCache};
use crate::DiskGetLen;
use crate::{DiskFile, DiskGetLen};
#[sorted]
#[derive(Debug)]
@ -1364,13 +1364,13 @@ impl QcowFile {
Ok(())
}
// Reads `count` bytes starting at `address`, calling `cb` repeatedly with the backing file,
// number of bytes read so far, and number of bytes to read from the file in that invocation. If
// None is given to `cb` in place of the backing file, the `cb` should infer zeros would have
// been read.
// Reads `count` bytes starting at `address`, calling `cb` repeatedly with the data source,
// number of bytes read so far, offset to read from, and number of bytes to read from the file
// in that invocation. If None is given to `cb` in place of the backing file, the `cb` should
// infer zeros would have been read.
fn read_cb<F>(&mut self, address: u64, count: usize, mut cb: F) -> std::io::Result<usize>
where
F: FnMut(Option<&mut File>, usize, usize) -> std::io::Result<()>,
F: FnMut(Option<&mut dyn DiskFile>, usize, u64, usize) -> std::io::Result<()>,
{
let read_count: usize = self.limit_range_file(address, count);
@ -1381,10 +1381,9 @@ impl QcowFile {
let count = self.limit_range_cluster(curr_addr, read_count - nread);
if let Some(offset) = file_offset {
self.raw_file.file_mut().seek(SeekFrom::Start(offset))?;
cb(Some(self.raw_file.file_mut()), nread, count)?;
cb(Some(self.raw_file.file_mut()), nread, offset, count)?;
} else {
cb(None, nread, count)?;
cb(None, nread, 0, count)?;
}
nread += count;
@ -1433,20 +1432,21 @@ impl AsRawFd for QcowFile {
impl Read for QcowFile {
fn read(&mut self, buf: &mut [u8]) -> std::io::Result<usize> {
let read_count =
self.read_cb(
self.current_offset,
buf.len(),
|file, offset, count| match file {
Some(f) => f.read_exact(&mut buf[offset..(offset + count)]),
let slice = buf.get_slice(0, buf.len() as u64).unwrap();
let read_count = self.read_cb(
self.current_offset,
buf.len(),
|file, already_read, offset, count| {
let sub_slice = slice.get_slice(already_read as u64, count as u64).unwrap();
match file {
Some(f) => f.read_exact_at_volatile(sub_slice, offset),
None => {
for b in &mut buf[offset..(offset + count)] {
*b = 0;
}
sub_slice.write_bytes(0);
Ok(())
}
},
)?;
}
},
)?;
self.current_offset += read_count as u64;
Ok(read_count)
}
@ -1506,10 +1506,10 @@ impl FileReadWriteVolatile for QcowFile {
let read_count = self.read_cb(
self.current_offset,
slice.size() as usize,
|file, offset, count| {
let sub_slice = slice.get_slice(offset as u64, count as u64).unwrap();
|file, read, offset, count| {
let sub_slice = slice.get_slice(read as u64, count as u64).unwrap();
match file {
Some(f) => f.read_exact_volatile(sub_slice),
Some(f) => f.read_exact_at_volatile(sub_slice, offset),
None => {
sub_slice.write_bytes(0);
Ok(())
@ -1537,16 +1537,20 @@ impl FileReadWriteVolatile for QcowFile {
impl FileReadWriteAtVolatile for QcowFile {
fn read_at_volatile(&mut self, slice: VolatileSlice, offset: u64) -> io::Result<usize> {
self.read_cb(offset, slice.size() as usize, |file, offset, count| {
let sub_slice = slice.get_slice(offset as u64, count as u64).unwrap();
match file {
Some(f) => f.read_exact_volatile(sub_slice),
None => {
sub_slice.write_bytes(0);
Ok(())
self.read_cb(
offset,
slice.size() as usize,
|file, read, offset, count| {
let sub_slice = slice.get_slice(read as u64, count as u64).unwrap();
match file {
Some(f) => f.read_exact_at_volatile(sub_slice, offset),
None => {
sub_slice.write_bytes(0);
Ok(())
}
}
}
})
},
)
}
fn write_at_volatile(&mut self, slice: VolatileSlice, offset: u64) -> io::Result<usize> {