Struct VhdxReader 

pub struct VhdxReader { /* private fields */ }

Read-only VHDX container reader.

Implements Read + Seek over the virtual sector stream.

Bounded memory

The reader holds the BAT (a small Vec<u64>), the parsed metadata, and a log overlay (empty for a clean image, ~log-sized for a dirty one) — never the whole container. Block bytes are fetched on demand from a positioned Backing, so peak RSS does not scale with image size. VhdxReader::open takes the bounded Backing::File path; VhdxReader::from_bytes keeps the legacy in-RAM path (backed by Backing::Mem).

Implementations

impl VhdxReader

pub fn open(path: &Path) -> Result<Self>

Open a VHDX container from a path with bounded memory.

Reads only the small fixed structures (headers, region table, metadata, BAT, and — for a dirty image — the log region) at construction; the payload blocks are read on demand. A 2 TB image no longer means a 2 TB heap.

pub fn from_backing( backing: Backing, parent: Option<Box<VhdxReader>>, ) -> Result<Self>

Construct a reader over an arbitrary positioned Backing.

The escape hatch behind open (and the issen zip bridge): a Backing::Sub reads a STORED zip entry in place, a Backing::Mem reads inflated/owned bytes. Parsing and reads are identical across all three backings.

pub fn from_bytes(data: Vec<u8>) -> Result<Self>

Open a VHDX container from owned bytes (legacy in-RAM path).

The whole buffer is held in RAM (via Backing::Mem) and the dirty log, if any, is replayed in place before parsing — byte-identical to the historical behaviour. Prefer open for files on disk.

pub fn from_bytes_with_parent(data: Vec<u8>, parent: VhdxReader) -> Result<Self>

Open a differencing (child) disk with its parent chain (in-RAM path).

Reads absent blocks from parent instead of returning zeros.

pub fn from_backing_with_parent( backing: Backing, parent: VhdxReader, ) -> Result<Self>

Open a differencing (child) disk over an arbitrary backing with its parent chain.

pub fn virtual_disk_size(&self) -> u64

pub fn logical_sector_size(&self) -> u32

Trait Implementations

impl Debug for VhdxReader

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Read for VhdxReader

fn read(&mut self, buf: &mut [u8]) -> Result<usize>

Pull some bytes from this source into the specified buffer, returning how many bytes were read.

fn read_vectored(&mut self, bufs: &mut [IoSliceMut<'_>]) -> Result<usize, Error>

Like read, except that it reads into a slice of buffers.

fn is_read_vectored(&self) -> bool

🔬This is a nightly-only experimental API. (can_vector)

Determines if this Reader has an efficient read_vectored implementation.

fn read_to_end(&mut self, buf: &mut Vec<u8>) -> Result<usize, Error>

Reads all bytes until EOF in this source, placing them into buf.

fn read_to_string(&mut self, buf: &mut String) -> Result<usize, Error>

Reads all bytes until EOF in this source, appending them to buf.

fn read_exact(&mut self, buf: &mut [u8]) -> Result<(), Error>

Reads the exact number of bytes required to fill buf.

fn read_buf(&mut self, buf: BorrowedCursor<'_, u8>) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Pull some bytes from this source into the specified buffer.

fn read_buf_exact( &mut self, cursor: BorrowedCursor<'_, u8>, ) -> Result<(), Error>

🔬This is a nightly-only experimental API. (read_buf)

Reads the exact number of bytes required to fill cursor.

fn by_ref(&mut self) -> &mut Self

where Self: Sized,

Creates a “by reference” adapter for this instance of Read.

fn bytes(self) -> Bytes<Self>

where Self: Sized,

Transforms this Read instance to an Iterator over its bytes.

fn chain<R>(self, next: R) -> Chain<Self, R>

where R: Read, Self: Sized,

Creates an adapter which will chain this stream with another.

fn take(self, limit: u64) -> Take<Self>

where Self: Sized,

Creates an adapter which will read at most limit bytes from it.

fn read_array<const N: usize>(&mut self) -> Result<[u8; N], Error>

where Self: Sized,

🔬This is a nightly-only experimental API. (read_array)

Read and return a fixed array of bytes from this source.

fn read_le<T>(&mut self) -> Result<T, Error>

where T: FromEndianBytes, Self: Sized,

🔬This is a nightly-only experimental API. (read_le)

Read and return a type (e.g. an integer) in little-endian order.

fn read_be<T>(&mut self) -> Result<T, Error>

where T: FromEndianBytes, Self: Sized,

🔬This is a nightly-only experimental API. (read_le)

Read and return a type (e.g. an integer) in big-endian order.

impl Seek for VhdxReader

fn seek(&mut self, pos: SeekFrom) -> Result<u64>

Seek to an offset, in bytes, in a stream.

fn rewind(&mut self) -> Result<(), Error>

Rewind to the beginning of a stream.

fn stream_len(&mut self) -> Result<u64, Error>

🔬This is a nightly-only experimental API. (seek_stream_len)

Returns the length of this stream (in bytes).

fn stream_position(&mut self) -> Result<u64, Error>

Returns the current seek position from the start of the stream.

fn seek_relative(&mut self, offset: i64) -> Result<(), Error>

Seeks relative to the current position.