Struct smithay_client_toolkit::shm::mempool::MemPool[][src]

pub struct MemPool {
    file: File,
    len: usize,
    pool: Main<WlShmPool>,
    buffer_count: Rc<RefCell<u32>>,
    mmap: MmapMut,
    callback: Rc<RefCell<dyn FnMut(DispatchData<'_>)>>,
}
Expand description

A wrapper handling an SHM memory pool backed by a shared memory file

This wrapper handles for you the creation of the shared memory file and its synchronization with the protocol.

Mempool internally tracks the release of the buffers by the compositor. As such, creating a buffer that is not commited to a surface (and then never released by the server) would cause the Mempool to be stuck believing it is still in use.

Mempool will also handle the destruction of buffers and as such the destroy() method should not be used on buffers created from Mempool.

Overwriting the contents of the memory pool before it is completely freed may cause graphical glitches due to the possible corruption of data while the compositor is reading it.

Mempool requires a callback that will be called when the pool becomes free, this happens when all the pools buffers are released by the server.

Fields

file: Filelen: usizepool: Main<WlShmPool>buffer_count: Rc<RefCell<u32>>mmap: MmapMutcallback: Rc<RefCell<dyn FnMut(DispatchData<'_>)>>

Implementations

Create a new memory pool associated with given shm

Resize the memory pool

This affect the size as it is seen by the wayland server. Even if you extend the temporary file size by writing to it, you need to call this method otherwise the server won’t see the new size.

Memory pools can only be extented, as such this method will do nothing if the requested new size is smaller than the current size.

This method allows you to ensure the underlying pool is large enough to hold what you want to write to it.

Create a new buffer to this pool

The parameters are:

  • offset: the offset (in bytes) from the beginning of the pool at which this buffer starts
  • width: the width of this buffer (in pixels)
  • height: the height of this buffer (in pixels)
  • stride: distance (in bytes) between the beginning of a row and the next one
  • format: the encoding format of the pixels. Using a format that was not advertised to the wl_shm global by the server is a protocol error and will terminate your connection

Uses the memmap2 crate to map the underlying shared memory file

Returns true if the pool contains buffers that are currently in use by the server

Trait Implementations

Executes the destructor for this type. Read more

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

Rewind to the beginning of a stream. Read more

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

Returns the length of this stream (in bytes). Read more

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

Write a buffer into this writer, returning how many bytes were written. Read more

Flush this output stream, ensuring that all intermediately buffered contents reach their destination. Read more

Like write, except that it writes from a slice of buffers. Read more

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

Determines if this Writer has an efficient write_vectored implementation. Read more

Attempts to write an entire buffer into this writer. Read more

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

Attempts to write multiple buffers into this writer. Read more

Writes a formatted string into this writer, returning any error encountered. Read more

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

Auto Trait Implementations

Blanket Implementations

Gets the TypeId of self. Read more

Immutably borrows from an owned value. Read more

Mutably borrows from an owned value. Read more

Performs the conversion.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.

The type returned in the event of a conversion error.

Performs the conversion.