protection of parallel requests of TxHashSetRequest (#1923)

* protection of parallel requests of TxHashSetRequest

* fix: adapt the test of test_unexpected_zip

chain/src/chain.rs

@@ -626,7 +626,7 @@ impl Chain {
 		}
 
 		// prepares the zip and return the corresponding Read
-		let txhashset_reader = txhashset::zip_read(self.db_root.clone(), &header)?;
+		let txhashset_reader = txhashset::zip_read(self.db_root.clone(), &header, None)?;
 		Ok((
 			header.output_mmr_size,
 			header.kernel_mmr_size,

chain/src/txhashset/txhashset.rs

@@ -19,7 +19,7 @@ use std::collections::HashSet;
 use std::fs::{self, File};
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
-use std::time::Instant;
+use std::time::{Instant, SystemTime, UNIX_EPOCH};
 
 use croaring::Bitmap;
 
@@ -52,7 +52,7 @@ const OUTPUT_SUBDIR: &'static str = "output";
 const RANGE_PROOF_SUBDIR: &'static str = "rangeproof";
 const KERNEL_SUBDIR: &'static str = "kernel";
 
-const TXHASHSET_ZIP: &'static str = "txhashset_snapshot.zip";
+const TXHASHSET_ZIP: &'static str = "txhashset_snapshot";
 
 struct HashOnlyMMRHandle {
 	backend: HashOnlyMMRBackend,
@@ -1349,13 +1349,22 @@ impl<'a> Extension<'a> {
 
 /// Packages the txhashset data files into a zip and returns a Read to the
 /// resulting file
-pub fn zip_read(root_dir: String, header: &BlockHeader) -> Result<File, Error> {
+pub fn zip_read(root_dir: String, header: &BlockHeader, rand: Option<u32>) -> Result<File, Error> {
+	let ts = if let None = rand {
+		let now = SystemTime::now();
+		now.duration_since(UNIX_EPOCH).unwrap().subsec_micros()
+	} else {
+		rand.unwrap()
+	};
+	let txhashset_zip = format!("{}_{}.zip", TXHASHSET_ZIP, ts);
+
 	let txhashset_path = Path::new(&root_dir).join(TXHASHSET_SUBDIR);
-	let zip_path = Path::new(&root_dir).join(TXHASHSET_ZIP);
+	let zip_path = Path::new(&root_dir).join(txhashset_zip);
 	// create the zip archive
 	{
 		// Temp txhashset directory
-		let temp_txhashset_path = Path::new(&root_dir).join(TXHASHSET_SUBDIR.to_string() + "_zip");
+		let temp_txhashset_path =
+			Path::new(&root_dir).join(format!("{}_zip_{}", TXHASHSET_SUBDIR, ts));
 		// Remove temp dir if it exist
 		if temp_txhashset_path.exists() {
 			fs::remove_dir_all(&temp_txhashset_path)?;
@@ -1455,7 +1464,11 @@ fn check_and_remove_files(txhashset_path: &PathBuf, header: &BlockHeader) -> Res
 			);
 			for diff in difference {
 				let diff_path = subdirectory_path.join(diff);
-				file::delete(diff_path)?;
+				file::delete(diff_path.clone())?;
+				debug!(
+					"check_and_remove_files: unexpected file '{:?}' removed",
+					diff_path
+				);
 			}
 		}
 	}

chain/tests/test_txhashset.rs

@@ -23,6 +23,7 @@ use std::fs::{self, File, OpenOptions};
 use std::iter::FromIterator;
 use std::path::{Path, PathBuf};
 use std::sync::Arc;
+use std::time::{SystemTime, UNIX_EPOCH};
 
 use chain::store::ChainStore;
 use chain::txhashset;
@@ -35,6 +36,9 @@ fn clean_output_dir(dir_name: &str) {
 
 #[test]
 fn test_unexpected_zip() {
+	let now = SystemTime::now();
+	let rand = now.duration_since(UNIX_EPOCH).unwrap().subsec_micros();
+
 	let db_root = format!(".grin_txhashset_zip");
 	clean_output_dir(&db_root);
 	let db_env = Arc::new(store::new_env(db_root.clone()));
@@ -42,22 +46,22 @@ fn test_unexpected_zip() {
 	let store = Arc::new(chain_store);
 	txhashset::TxHashSet::open(db_root.clone(), store.clone(), None).unwrap();
 	// First check if everything works out of the box
-	assert!(txhashset::zip_read(db_root.clone(), &BlockHeader::default()).is_ok());
-	let zip_path = Path::new(&db_root).join("txhashset_snapshot.zip");
+	assert!(txhashset::zip_read(db_root.clone(), &BlockHeader::default(), Some(rand)).is_ok());
+	let zip_path = Path::new(&db_root).join(format!("txhashset_snapshot_{}.zip", rand));
 	let zip_file = File::open(&zip_path).unwrap();
 	assert!(txhashset::zip_write(db_root.clone(), zip_file, &BlockHeader::default()).is_ok());
 	// Remove temp txhashset dir
-	fs::remove_dir_all(Path::new(&db_root).join("txhashset_zip")).unwrap();
+	fs::remove_dir_all(Path::new(&db_root).join(format!("txhashset_zip_{}", rand))).unwrap();
 	// Then add strange files in the original txhashset folder
 	write_file(db_root.clone());
-	assert!(txhashset::zip_read(db_root.clone(), &BlockHeader::default()).is_ok());
+	assert!(txhashset::zip_read(db_root.clone(), &BlockHeader::default(), Some(rand)).is_ok());
 	// Check that the temp dir dos not contains the strange files
-	let txhashset_zip_path = Path::new(&db_root).join("txhashset_zip");
+	let txhashset_zip_path = Path::new(&db_root).join(format!("txhashset_zip_{}", rand));
 	assert!(txhashset_contains_expected_files(
-		"txhashset_zip".to_string(),
+		format!("txhashset_zip_{}", rand),
 		txhashset_zip_path.clone()
 	));
-	fs::remove_dir_all(Path::new(&db_root).join("txhashset_zip")).unwrap();
+	fs::remove_dir_all(Path::new(&db_root).join(format!("txhashset_zip_{}", rand))).unwrap();
 
 	let zip_file = File::open(zip_path).unwrap();
 	assert!(txhashset::zip_write(db_root.clone(), zip_file, &BlockHeader::default()).is_ok());