wasm-executor: Support growing the memory (#12520)

* As always, start with something :P

* Add support for max_heap_pages

* Add support for wasmtime

* Make it compile

* Fix compilation

* Copy wrongly merged code

* Fix compilation

* Some fixes

* Fix

* Get stuff working

* More work

* More fixes

* ...

* More

* FIXEs

* Switch wasmi to use `RuntimeBlob` like wasmtime

* Removed unused stuff

* Cleanup

* More cleanups

* Introduce `CallContext`

* Fixes

* More fixes

* Add builder for creating the `WasmExecutor`

* Adds some docs

* FMT

* First round of feedback.

* Review feedback round 2

* More fixes

* Fix try-runtime

* Update client/executor/wasmtime/src/instance_wrapper.rs

Co-authored-by: Koute <koute@users.noreply.github.com>

* Update client/executor/common/src/wasm_runtime.rs

Co-authored-by: Koute <koute@users.noreply.github.com>

* Update client/executor/common/src/runtime_blob/runtime_blob.rs

Co-authored-by: Koute <koute@users.noreply.github.com>

* Update client/executor/common/src/wasm_runtime.rs

Co-authored-by: Koute <koute@users.noreply.github.com>

* Update client/allocator/src/freeing_bump.rs

Co-authored-by: Koute <koute@users.noreply.github.com>

* Update client/allocator/src/freeing_bump.rs

Co-authored-by: Koute <koute@users.noreply.github.com>

* Feedback round 3

* FMT

* Review comments

---------

Co-authored-by: Koute <koute@users.noreply.github.com>

substrate/client/allocator/src/lib.rs

@@ -27,3 +27,35 @@ mod freeing_bump;
 
 pub use error::Error;
 pub use freeing_bump::{AllocationStats, FreeingBumpHeapAllocator};
+
+/// The size of one wasm page in bytes.
+///
+/// The wasm memory is divided into pages, meaning the minimum size of a memory is one page.
+const PAGE_SIZE: u32 = 65536;
+
+/// The maximum number of wasm pages that can be allocated.
+///
+/// 4GiB / [`PAGE_SIZE`].
+const MAX_WASM_PAGES: u32 = (4u64 * 1024 * 1024 * 1024 / PAGE_SIZE as u64) as u32;
+
+/// Grants access to the memory for the allocator.
+///
+/// Memory of wasm is allocated in pages. A page has a constant size of 64KiB. The maximum allowed
+/// memory size as defined in the wasm specification is 4GiB (65536 pages).
+pub trait Memory {
+	/// Run the given closure `run` and grant it write access to the raw memory.
+	fn with_access_mut<R>(&mut self, run: impl FnOnce(&mut [u8]) -> R) -> R;
+	/// Run the given closure `run` and grant it read access to the raw memory.
+	fn with_access<R>(&self, run: impl FnOnce(&[u8]) -> R) -> R;
+	/// Grow the memory by `additional` pages.
+	fn grow(&mut self, additional: u32) -> Result<(), ()>;
+	/// Returns the current number of pages this memory has allocated.
+	fn pages(&self) -> u32;
+	/// Returns the maximum number of pages this memory is allowed to allocate.
+	///
+	/// The returned number needs to be smaller or equal to `65536`. The returned number needs to be
+	/// bigger or equal to [`Self::pages`].
+	///
+	/// If `None` is returned, there is no maximum (besides the maximum defined in the wasm spec).
+	fn max_pages(&self) -> Option<u32>;
+}