[NUnit] Concurrent-safe AbstractResultsStore

This is a tentative fix for a concurrency case on registering unit tests.
Based on the stacktrace in the bug report, this seems like the TestRecord
is modified concurrently, thus causing issues on getting an item that
would've been added/removed (i.e. array resize).

Bug 42513 - Test result store seems to be corrupted - internal error when running many tests

Author: Therzok

main/src/addins/MonoDevelop.UnitTesting/Services/AbstractResultsStore.cs

@@ -87,44 +87,48 @@ record = ctr;
 				record.Results.Add (result);
 			}
 		}
-		
+
 		public UnitTestResult GetNextResult (string configuration, UnitTest test, DateTime date)
 		{
 			DateTime currentDate = date;
-			TestRecord root = GetRootRecord (configuration, currentDate);
-			if (root == null)
-				root = GetNextRootRecord (configuration, ref currentDate);
-			
-			while (root != null) {
-				TestRecord tr = FindRecord (root, test.StoreRelativeName);
-				if (tr != null && tr.Results != null) {
-					foreach (UnitTestResult res in tr.Results) {
-						if (res.TestDate > date)
-							return res;
+			lock (fileCache) {
+				TestRecord root = GetRootRecord (configuration, currentDate);
+				if (root == null)
+					root = GetNextRootRecord (configuration, ref currentDate);
+
+				while (root != null) {
+					TestRecord tr = FindRecord (root, test.StoreRelativeName);
+					if (tr != null && tr.Results != null) {
+						foreach (UnitTestResult res in tr.Results) {
+							if (res.TestDate > date)
+								return res;
+						}
 					}
+					root = GetNextRootRecord (configuration, ref currentDate);
 				}
-				root = GetNextRootRecord (configuration, ref currentDate);
 			}
 			return null;
 		}
 
 		public UnitTestResult GetPreviousResult (string configuration, UnitTest test, DateTime date)
 		{
 			DateTime currentDate = date;
-			TestRecord root = GetRootRecord (configuration, currentDate);
-			if (root == null)
-				root = GetPreviousRootRecord (configuration, ref currentDate);
-			
-			while (root != null) {
-				TestRecord tr = FindRecord (root, test.StoreRelativeName);
-				if (tr != null && tr.Results != null) {
-					for (int n = tr.Results.Count - 1; n >= 0; n--) {
-						UnitTestResult res = (UnitTestResult) tr.Results [n];
-						if (res.TestDate < date)
-							return res;
+			lock (fileCache) {
+				TestRecord root = GetRootRecord (configuration, currentDate);
+				if (root == null)
+					root = GetPreviousRootRecord (configuration, ref currentDate);
+
+				while (root != null) {
+					TestRecord tr = FindRecord (root, test.StoreRelativeName);
+					if (tr != null && tr.Results != null) {
+						for (int n = tr.Results.Count - 1; n >= 0; n--) {
+							UnitTestResult res = (UnitTestResult)tr.Results [n];
+							if (res.TestDate < date)
+								return res;
+						}
 					}
+					root = GetPreviousRootRecord (configuration, ref currentDate);
 				}
-				root = GetPreviousRootRecord (configuration, ref currentDate);
 			}
 			return null;
 		}
@@ -140,21 +144,23 @@ public UnitTestResult[] GetResults (string configuration, UnitTest test, DateTim
 			DateTime firstDay = new DateTime (startDate.Year, startDate.Month, startDate.Day);
 
 			DateTime[] dates = GetStoreDates (configuration);
-			
-			foreach (DateTime date in dates) {
-				if (date < firstDay)
-					continue;
-				if (date > endDate)
-					break;
-				
-				TestRecord root = GetRootRecord (configuration, date);
-				if (root == null) continue;
 
-				TestRecord tr = FindRecord (root, test.StoreRelativeName);
-				if (tr != null && tr.Results != null) {
-					foreach (UnitTestResult res in tr.Results) {
-						if (res.TestDate >= startDate && res.TestDate <= endDate)
-							list.Add (res);
+			lock (fileCache) {
+				foreach (DateTime date in dates) {
+					if (date < firstDay)
+						continue;
+					if (date > endDate)
+						break;
+
+					TestRecord root = GetRootRecord (configuration, date);
+					if (root == null) continue;
+
+					TestRecord tr = FindRecord (root, test.StoreRelativeName);
+					if (tr != null && tr.Results != null) {
+						foreach (UnitTestResult res in tr.Results) {
+							if (res.TestDate >= startDate && res.TestDate <= endDate)
+								list.Add (res);
+						}
 					}
 				}
 			}
@@ -166,20 +172,22 @@ public UnitTestResult[] GetResultsToDate (string configuration, UnitTest test, D
 		{
 			ArrayList list = new ArrayList ();
 			DateTime[] dates = GetStoreDates (configuration);
-			
-			for (int n = dates.Length - 1; n >= 0 && list.Count < count; n--) {
-				if (dates [n] > endDate)
-					continue;
-				
-				TestRecord root = GetRootRecord (configuration, dates [n]);
-				if (root == null) continue;
 
-				TestRecord tr = FindRecord (root, test.StoreRelativeName);
-				if (tr != null && tr.Results != null) {
-					for (int m = tr.Results.Count - 1; m >= 0 && list.Count < count; m--) {
-						UnitTestResult res = (UnitTestResult) tr.Results [m];
-						if (res.TestDate <= endDate)
-							list.Add (res);
+			lock (fileCache) {
+				for (int n = dates.Length - 1; n >= 0 && list.Count < count; n--) {
+					if (dates [n] > endDate)
+						continue;
+
+					TestRecord root = GetRootRecord (configuration, dates [n]);
+					if (root == null) continue;
+
+					TestRecord tr = FindRecord (root, test.StoreRelativeName);
+					if (tr != null && tr.Results != null) {
+						for (int m = tr.Results.Count - 1; m >= 0 && list.Count < count; m--) {
+							UnitTestResult res = (UnitTestResult)tr.Results [m];
+							if (res.TestDate <= endDate)
+								list.Add (res);
+						}
 					}
 				}
 			}
@@ -193,21 +201,24 @@ public void Save ()
 		{
 			if (!Directory.Exists (basePath))
 				Directory.CreateDirectory (basePath);
-			
-			foreach (DictionaryEntry entry in fileCache) {
-				TestRecord record = (TestRecord) entry.Value;
-				if (!record.Modified)
-					continue;
-				
-				string filePath = Path.Combine (basePath, (string)entry.Key);
-				try {
-					serializer.Serialize (filePath, record);
-					record.Modified = false;
-				} catch (Exception ex) {
-					LoggingService.LogError (ex.ToString ());
+
+			lock (fileCache) {
+				foreach (DictionaryEntry entry in fileCache) {
+					TestRecord record = (TestRecord)entry.Value;
+					if (!record.Modified)
+						continue;
+
+					string filePath = Path.Combine (basePath, (string)entry.Key);
+					try {
+						serializer.Serialize (filePath, record);
+						record.Modified = false;
+					} catch (Exception ex) {
+						LoggingService.LogError (ex.ToString ());
+					}
 				}
 			}
-			cachedRootList.Clear ();
+			lock (cachedRootList)
+				cachedRootList.Clear ();
 		}
 
 		TestRecord FindRecord (TestRecord root, string aname)
@@ -313,22 +324,24 @@ DateTime[] GetStoreDates (string configuration)
 		{
 			if (!Directory.Exists (basePath))
 				return new DateTime [0];
-			
-			DateTime[] res = (DateTime[]) cachedRootList [configuration];
-			if (res != null)
+
+			lock (cachedRootList) {
+				DateTime [] res = (DateTime [])cachedRootList [configuration];
+				if (res != null)
+					return res;
+
+				var dates = new List<DateTime> ();
+				var escapedConfiguration = EscapeFilename (configuration);
+				foreach (string file in Directory.GetFiles (basePath, storeId + "-" + escapedConfiguration + "-*")) {
+					try {
+						DateTime t = ParseFileNameDate (escapedConfiguration, Path.GetFileName (file));
+						dates.Add (t);
+					} catch { }
+				}
+				res = dates.ToArray ();
+				cachedRootList [configuration] = res;
 				return res;
-			
-			var dates = new List<DateTime> ();
-			var escapedConfiguration = EscapeFilename (configuration);
-			foreach (string file in Directory.GetFiles (basePath, storeId + "-" + escapedConfiguration + "-*")) {
-				try {
-					DateTime t = ParseFileNameDate (escapedConfiguration, Path.GetFileName (file));
-					dates.Add (t);
-				} catch { }
 			}
-			res = dates.ToArray ();
-			cachedRootList [configuration] = res;
-			return res;
 		}
 	}