Add Windows support for storage monitor (paritytech#13466)

* Add Windows support for storage monitor

* Apply suggested changes

client/storage-monitor/Cargo.toml

@@ -12,7 +12,7 @@ homepage = "https://substrate.io"
 clap = { version = "4.0.9", features = ["derive", "string"] }
 futures = "0.3.21"
 log = "0.4.17"
-nix = { version = "0.26.1", features = ["fs"] }
+fs4 = "0.6.3"
 sc-client-db = { version = "0.10.0-dev", default-features = false, path = "../db" }
 sc-utils = { version = "4.0.0-dev", path = "../utils" }
 sp-core = { version = "7.0.0", path = "../../primitives/core" }

client/storage-monitor/src/lib.rs

@@ -17,10 +17,10 @@
 // along with this program. If not, see <https://www.gnu.org/licenses/>.
 
 use clap::Args;
-use nix::{errno::Errno, sys::statvfs::statvfs};
 use sc_client_db::DatabaseSource;
 use sp_core::traits::SpawnEssentialNamed;
 use std::{
+	io,
 	path::{Path, PathBuf},
 	time::Duration,
 };
@@ -31,7 +31,7 @@ const LOG_TARGET: &str = "storage-monitor";
 #[derive(Debug, thiserror::Error)]
 pub enum Error {
 	#[error("IO Error")]
-	IOError(#[from] Errno),
+	IOError(#[from] io::Error),
 	#[error("Out of storage space: available {0}MB, required {1}MB")]
 	StorageOutOfSpace(u64, u64),
 }
@@ -117,12 +117,7 @@ impl StorageMonitorService {
 
 	/// Returns free space in MB, or error if statvfs failed.
 	fn free_space(path: &Path) -> Result<u64, Error> {
-		statvfs(path)
-			.map(|stats| {
-				u64::from(stats.blocks_available()).saturating_mul(u64::from(stats.block_size())) /
-					1_000_000
-			})
-			.map_err(Error::from)
+		Ok(fs4::available_space(path).map(|s| s / 1_000_000)?)
 	}
 
 	/// Checks if the amount of free space for given `path` is above given `threshold`.