Struct RefBlock

pub(super) struct RefBlock {
    cluster: Option<HostCluster>,
    raw_data: IoBuffer,
    refcount_order: u32,
    cluster_bits: u32,
    modified: AtomicBool,
    writer_lock: Mutex<()>,
}

Refcount block.

Fields

cluster: Option<HostCluster>

Cluster in the image file.

raw_data: IoBuffer

Raw table data (big endian).

refcount_order: u32

log2 of the refcount bits.

cluster_bits: u32

log2 of the cluster size.

modified: AtomicBool

Whether this block has been modified since it was last written.

writer_lock: Mutex<()>

Lock for creating RefBlockWriteGuard.

Implementations

impl RefBlock

pub fn new_cleared<S: Storage>(for_image: &S, header: &Header) -> Result<Self>

Create a new zeroed refcount block.

pub async fn load<S: Storage>( image: &S, header: &Header, cluster: HostCluster, ) -> Result<Self>

Load a refcount block from disk.

pub async fn write<S: Storage>(&self, image: &S) -> Result<()>

Write a refcount block to disk.

pub fn get_cluster(&self) -> Option<HostCluster>

Get the block’s cluster in the image file.

pub fn get_offset(&self) -> Option<HostOffset>

Get the block’s offset in the image file.

pub fn set_cluster(&mut self, cluster: HostCluster)

Change the block’s cluster in the image file (for writing).

fn sub_byte_refcount_access(&self, index: usize) -> (usize, u8, usize)

Calculate sub-byte refcount access parameters.

For a given refcount index, return its:

• byte index,
• access mask,
• in-byte shift.

pub fn get(&self, index: usize) -> u64

Get the given cluster’s refcount.

pub async fn lock_write(&self) -> RefBlockWriteGuard<'_>

Allow modifying this refcount block.

Note that readers are allowed to exist while modifications are happening.

pub fn is_modified(&self) -> bool

Check whether this block has been modified since it was last written.

pub fn clear_modified(&self)

Clear the modified flag.

pub fn set_modified(&self)

Set the modified flag.

pub fn is_zero(&self, index: usize) -> bool

Check whether the given cluster’s refcount is 0.

Trait Implementations

impl Drop for RefBlock

fn drop(&mut self)

Executes the destructor for this type.