wasmer 7.2.0-rc.1

High-performance WebAssembly runtime
Documentation
use super::{SharedMemory, shared_memory_detach_error, view::*};
use wasmer_types::{MemoryError, MemoryType, Pages};

use crate::{
    AsStoreMut, AsStoreRef, ExportError, Exportable, Extern, StoreMut, StoreRef,
    macros::backend::{gen_rt_ty, match_rt},
    vm::{VMExtern, VMExternMemory, VMMemory},
};

gen_rt_ty! {
    #[cfg_attr(feature = "artifact-size", derive(loupe::MemoryUsage))]
    #[derive(Debug, Clone, PartialEq, Eq, derive_more::From)]
    pub BackendMemory(entities::memory::Memory);
}

impl BackendMemory {
    /// Creates a new host [`BackendMemory`] from the provided [`MemoryType`].
    ///
    /// This function will construct the `Memory` using the store
    /// `BaseTunables`.
    ///
    /// # Example
    ///
    /// ```
    /// # use wasmer::{Memory, MemoryType, Pages, Store, Type, Value};
    /// # let mut store = Store::default();
    /// #
    /// let m = Memory::new(&mut store, MemoryType::new(1, None, false)).unwrap();
    /// ```
    #[inline]
    pub fn new(store: &mut impl AsStoreMut, ty: MemoryType) -> Result<Self, MemoryError> {
        match &store.as_store_mut().inner.store {
            #[cfg(feature = "sys")]
            crate::BackendStore::Sys(s) => Ok(Self::Sys(
                crate::backend::sys::entities::memory::Memory::new(store, ty)?,
            )),
            #[cfg(feature = "v8")]
            crate::BackendStore::V8(s) => Ok(Self::V8(
                crate::backend::v8::entities::memory::Memory::new(store, ty)?,
            )),
            #[cfg(feature = "js")]
            crate::BackendStore::Js(s) => Ok(Self::Js(
                crate::backend::js::entities::memory::Memory::new(store, ty)?,
            )),
        }
    }

    /// Create a memory object from an existing memory and attaches it to the store
    #[inline]
    pub fn new_from_existing(new_store: &mut impl AsStoreMut, memory: VMMemory) -> Self {
        match new_store.as_store_mut().inner.store {
            #[cfg(feature = "sys")]
            crate::BackendStore::Sys(_) => Self::Sys(
                crate::backend::sys::entities::memory::Memory::new_from_existing(
                    new_store,
                    memory.unwrap_sys(),
                ),
            ),
            #[cfg(feature = "v8")]
            crate::BackendStore::V8(_) => Self::V8(
                crate::backend::v8::entities::memory::Memory::new_from_existing(
                    new_store,
                    memory.unwrap_v_8(),
                ),
            ),
            #[cfg(feature = "js")]
            crate::BackendStore::Js(_) => Self::Js(
                crate::backend::js::entities::memory::Memory::new_from_existing(
                    new_store,
                    memory.unwrap_js(),
                ),
            ),
        }
    }

    /// Returns the [`MemoryType`] of the [`BackendMemory`].
    ///
    /// # Example
    ///
    /// ```
    /// # use wasmer::{Memory, MemoryType, Pages, Store, Type, Value};
    /// # let mut store = Store::default();
    /// #
    /// let mt = MemoryType::new(1, None, false);
    /// let m = Memory::new(&mut store, mt).unwrap();
    ///
    /// assert_eq!(m.ty(&mut store), mt);
    /// ```
    #[inline]
    pub fn ty(&self, store: &impl AsStoreRef) -> MemoryType {
        match_rt!(on self => s {
            s.ty(store)
        })
    }

    /// Retrieve the size of the memory in pages.
    pub fn size(&self, store: &impl AsStoreRef) -> Pages {
        match_rt!(on self => s {
            s.size(store)
        })
    }

    /// Grow memory by the specified amount of WebAssembly [`Pages`] and return
    /// the previous memory size.
    ///
    /// # Example
    ///
    /// ```
    /// # use wasmer::{Memory, MemoryType, Pages, Store, Type, Value, WASM_MAX_PAGES};
    /// # let mut store = Store::default();
    /// #
    /// let m = Memory::new(&mut store, MemoryType::new(1, Some(3), false)).unwrap();
    /// let p = m.grow(&mut store, 2).unwrap();
    ///
    /// assert_eq!(p, Pages(1));
    /// assert_eq!(m.view(&mut store).size(), Pages(3));
    /// ```
    ///
    /// # Errors
    ///
    /// Returns an error if memory can't be grown by the specified amount
    /// of pages.
    ///
    /// ```should_panic
    /// # use wasmer::{Memory, MemoryType, Pages, Store, Type, Value, WASM_MAX_PAGES};
    /// # use wasmer::FunctionEnv;
    /// # let mut store = Store::default();
    /// # let env = FunctionEnv::new(&mut store, ());
    /// #
    /// let m = Memory::new(&mut store, MemoryType::new(1, Some(1), false)).unwrap();
    ///
    /// // This results in an error: `MemoryError::CouldNotGrow`.
    /// let s = m.grow(&mut store, 1).unwrap();
    /// ```
    #[inline]
    pub fn grow<IntoPages>(
        &self,
        store: &mut impl AsStoreMut,
        delta: IntoPages,
    ) -> Result<Pages, MemoryError>
    where
        IntoPages: Into<Pages>,
    {
        match_rt!(on self => s {
            s.grow(store, delta)
        })
    }

    /// Grows the memory to at least a minimum size.
    ///
    /// # Note
    ///
    /// If the memory is already big enough for the min size this function does nothing.
    #[inline]
    pub fn grow_at_least(
        &self,
        store: &mut impl AsStoreMut,
        min_size: u64,
    ) -> Result<(), MemoryError> {
        match_rt!(on self => s {
            s.grow_at_least(store, min_size)
        })
    }

    /// Resets the memory back to zero length
    #[inline]
    pub fn reset(&self, store: &mut impl AsStoreMut) -> Result<(), MemoryError> {
        match_rt!(on self => s {
            s.reset(store)
        })
    }

    /// Attempts to duplicate this memory in a new store with a byte-for-byte copy
    #[inline]
    #[deprecated(
        since = "8.0.0",
        note = "Since `Store` is no longer `Send + Sync`, this method cannot be used meaningfully. \
                Use `copy`, then `attach` on the thread owning the other `Store` instead."
    )]
    pub fn copy_to_store(
        &self,
        store: &impl AsStoreRef,
        new_store: &mut impl AsStoreMut,
    ) -> Result<Self, MemoryError> {
        self.copy(store)
            .map(|new_memory| new_memory.attach(new_store).0)
    }

    #[inline]
    pub(crate) fn from_vm_extern(store: &mut impl AsStoreMut, vm_extern: VMExternMemory) -> Self {
        match &store.as_store_mut().inner.store {
            #[cfg(feature = "sys")]
            crate::BackendStore::Sys(s) => Self::Sys(
                crate::backend::sys::entities::memory::Memory::from_vm_extern(store, vm_extern),
            ),
            #[cfg(feature = "v8")]
            crate::BackendStore::V8(s) => Self::V8(
                crate::backend::v8::entities::memory::Memory::from_vm_extern(store, vm_extern),
            ),
            #[cfg(feature = "js")]
            crate::BackendStore::Js(s) => Self::Js(
                crate::backend::js::entities::memory::Memory::from_vm_extern(store, vm_extern),
            ),
        }
    }

    /// Checks whether this `Memory` can be used with the given context.
    #[inline]
    pub fn is_from_store(&self, store: &impl AsStoreRef) -> bool {
        match_rt!(on self => s {
            s.is_from_store(store)
        })
    }

    /// Attempts to create a detached copied memory handle that can later be
    /// attached to a different store.
    #[inline]
    pub fn copy(&self, store: &impl AsStoreRef) -> Result<SharedMemory, MemoryError> {
        match_rt!(on self => s {
            s.copy(store)
        })
    }

    /// Attempts to clone this memory (if its cloneable) in a new store
    /// (cloned memory will be shared between those that clone it)
    #[inline]
    #[deprecated(
        since = "8.0.0",
        note = "Since `Store` is no longer `Send + Sync`, this method cannot be used meaningfully. \
                Use `as_shared`, then `attach` on the thread owning the other `Store` instead."
    )]
    pub fn share_in_store(
        &self,
        store: &impl AsStoreRef,
        new_store: &mut impl AsStoreMut,
    ) -> Result<Self, MemoryError> {
        if !self.ty(store).shared {
            return Err(MemoryError::MemoryNotShared);
        }

        self.as_shared(store)
            .ok_or_else(shared_memory_detach_error)
            .map(|new_memory| new_memory.attach(new_store).0)
    }

    /// Get a [`SharedMemory`].
    ///
    /// Only returns `Some(_)` if the memory is shared, and if the target
    /// backend supports shared memory operations.
    ///
    /// See [`SharedMemory`] and its methods for more information.
    #[inline]
    pub fn as_shared(&self, store: &impl AsStoreRef) -> Option<SharedMemory> {
        if !self.ty(store).shared {
            return None;
        }

        match_rt!(on self => s {
            s.as_shared(store).ok()
        })
    }

    /// Create a [`VMExtern`] from self.
    #[inline]
    pub(crate) fn to_vm_extern(&self) -> VMExtern {
        match_rt!(on self => s {
            s.to_vm_extern()
        })
    }
}