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/*
 * Copyright 2023 Fluence Labs Limited
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

use crate::AsContextMut;
use crate::Export;
use crate::ResolveResult;
use crate::WasmBackend;

/// A handle to an instantiated Wasm module. Cloning is cheap.
pub trait Instance<WB: WasmBackend>: Clone {
    /// Returns an `Iterator` to all exports of this instance.
    fn export_iter<'a>(
        &'a self,
        store: <WB as WasmBackend>::ContextMut<'a>,
    ) -> Box<dyn Iterator<Item = (&'a str, Export<WB>)> + 'a>;

    /// Returns nth exported memory, None if there is no nth memory.
    /// No guaranties is known for memory order, but almost always a module has only one memory,
    /// hence the only valid value for `memory_index` is 0.
    fn get_nth_memory(
        &self,
        store: &mut impl AsContextMut<WB>,
        memory_index: u32, // TODO: refactor memory indexing with enums
    ) -> Option<<WB as WasmBackend>::Memory>;

    /// Returns a memory export with given name.
    /// # Errors:
    ///     Returns an error if there is no export with such name, or it is not a memory.
    fn get_memory(
        &self,
        store: &mut impl AsContextMut<WB>,
        memory_name: &str,
    ) -> ResolveResult<<WB as WasmBackend>::Memory>;

    /// Returns an exported function with the given name.
    /// # Errors:
    ///     Returns an error if there is no export with such name, or it is not a function.
    fn get_function(
        &self,
        store: &mut impl AsContextMut<WB>,
        name: &str,
    ) -> ResolveResult<<WB as WasmBackend>::ExportFunction>;
}