// This file is part of Substrate.

// Copyright (C) Parity Technologies (UK) Ltd.
// SPDX-License-Identifier: GPL-3.0-or-later WITH Classpath-exception-2.0

// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.

// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.

// You should have received a copy of the GNU General Public License
// along with this program. If not, see <https://www.gnu.org/licenses/>.

//! Tests that are only relevant for Linux.

mod smaps;

use super::mk_test_runtime;
use crate::WasmExecutionMethod;
use codec::Encode as _;
use sc_executor_common::wasm_runtime::DEFAULT_HEAP_ALLOC_STRATEGY;

use self::smaps::Smaps;

#[test]
fn memory_consumption_compiled() {
	let _ = sp_tracing::try_init_simple();

	if std::env::var("RUN_TEST").is_ok() {
		memory_consumption(WasmExecutionMethod::Compiled {
			instantiation_strategy:
				sc_executor_wasmtime::InstantiationStrategy::LegacyInstanceReuse,
		});
	} else {
		// We need to run the test in isolation, to not getting interfered by the other tests.
		let executable = std::env::current_exe().unwrap();
		let status = std::process::Command::new(executable)
			.env("RUN_TEST", "1")
			.args(&["--nocapture", "memory_consumption_compiled"])
			.status()
			.unwrap();

		assert!(status.success());
	}
}

fn memory_consumption(wasm_method: WasmExecutionMethod) {
	// This aims to see if linear memory stays backed by the physical memory after a runtime call.
	//
	// For that we make a series of runtime calls, probing the RSS for the VMA matching the linear
	// memory. After the call we expect RSS to be equal to 0.

	let runtime = mk_test_runtime(wasm_method, DEFAULT_HEAP_ALLOC_STRATEGY);

	let mut instance = runtime.new_instance().unwrap();
	let heap_base = instance
		.get_global_const("__heap_base")
		.expect("`__heap_base` is valid")
		.expect("`__heap_base` exists")
		.as_i32()
		.expect("`__heap_base` is an `i32`");

	fn probe_rss(instance: &dyn sc_executor_common::wasm_runtime::WasmInstance) -> usize {
		let base_addr = instance.linear_memory_base_ptr().unwrap() as usize;
		Smaps::new().get_rss(base_addr).expect("failed to get rss")
	}

	instance
		.call_export("test_dirty_plenty_memory", &(heap_base as u32, 1u32).encode())
		.unwrap();
	let probe_1 = probe_rss(&*instance);
	instance
		.call_export("test_dirty_plenty_memory", &(heap_base as u32, 1024u32).encode())
		.unwrap();
	let probe_2 = probe_rss(&*instance);

	assert_eq!(probe_1, 0);
	assert_eq!(probe_2, 0);
}