Merge pull request #219 from bgrainger/csharp7

Use C# 7 language features.

Author: bgrainger

src/MySqlConnector/ByteArrayReader.cs

@@ -6,16 +6,9 @@ internal sealed class ByteArrayReader
 	{
 		public ByteArrayReader(byte[] buffer, int offset, int length)
 		{
-			if (buffer == null)
-				throw new ArgumentNullException(nameof(buffer));
-			if (offset < 0)
-				throw new ArgumentOutOfRangeException(nameof(offset));
-			if (offset + length > buffer.Length)
-				throw new ArgumentOutOfRangeException(nameof(length));
-
-			m_buffer = buffer;
-			m_maxOffset = offset + length;
-			m_offset = offset;
+			m_buffer = buffer ?? throw new ArgumentNullException(nameof(buffer));
+			m_offset = offset >= 0 ? offset : throw new ArgumentOutOfRangeException(nameof(offset));
+			m_maxOffset = offset + length <= m_buffer.Length ? offset + length : throw new ArgumentOutOfRangeException(nameof(length));
 		}
 
 		public ByteArrayReader(ArraySegment<byte> arraySegment)
@@ -25,13 +18,8 @@ public ByteArrayReader(ArraySegment<byte> arraySegment)
 
 		public int Offset
 		{
-			get { return m_offset; }
-			set
-			{
-				if (value < 0 || value > m_maxOffset)
-					throw new ArgumentOutOfRangeException(nameof(value), "value must be between 0 and {0}".FormatInvariant(m_maxOffset));
-				m_offset = value;
-			}
+			get => m_offset;
+			set => m_offset = value >= 0 && value <= m_maxOffset ? value : throw new ArgumentOutOfRangeException(nameof(value), "value must be between 0 and {0}".FormatInvariant(m_maxOffset));
 		}
 
 		public byte ReadByte()

src/MySqlConnector/MySqlClient/Caches/CachedProcedure.cs

@@ -67,16 +67,12 @@ internal MySqlParameterCollection AlignParamsWithDb(MySqlParameterCollection par
 				MySqlParameter alignParam;
 				if (cachedParam.Direction == ParameterDirection.ReturnValue)
 				{
-					if (returnParam == null)
-						throw new InvalidOperationException($"Attempt to call stored function {FullyQualified} without specifying a return parameter");
-					alignParam = returnParam;
+					alignParam = returnParam ?? throw new InvalidOperationException($"Attempt to call stored function {FullyQualified} without specifying a return parameter");
 				}
 				else
 				{
 					var index = parameterCollection.NormalizedIndexOf(cachedParam.Name);
-					if (index == -1)
-						throw new ArgumentException($"Parameter '{cachedParam.Name}' not found in the collection.");
-					alignParam = parameterCollection[index];
+					alignParam = index >= 0 ? parameterCollection[index] : throw new ArgumentException($"Parameter '{cachedParam.Name}' not found in the collection.");
 				}
 
 				if (alignParam.Direction == default(ParameterDirection))

src/MySqlConnector/MySqlClient/CommandExecutors/TextCommandExecutor.cs

@@ -63,11 +63,11 @@ public virtual async Task<DbDataReader> ExecuteReaderAsync(string commandText, M
 				await m_command.Connection.Session.SendAsync(payload, ioBehavior, cancellationToken).ConfigureAwait(false);
 				return await MySqlDataReader.CreateAsync(m_command, behavior, ioBehavior, cancellationToken).ConfigureAwait(false);
 			}
-			catch (Exception ex) when (payload.ArraySegment.Count > 4194304 && (ex is SocketException || ex is IOException || ex is MySqlProtocolException))
+			catch (Exception ex) when (payload.ArraySegment.Count > 4_194_304 && (ex is SocketException || ex is IOException || ex is MySqlProtocolException))
 			{
 				// the default MySQL Server value for max_allowed_packet (in MySQL 5.7) is 4MiB: https://dev.mysql.com/doc/refman/5.7/en/server-system-variables.html#sysvar_max_allowed_packet
 				// use "decimal megabytes" (to round up) when creating the exception message
-				int megabytes = payload.ArraySegment.Count / 1000000;
+				int megabytes = payload.ArraySegment.Count / 1_000_000;
 				throw new MySqlException("Error submitting {0}MB packet; ensure 'max_allowed_packet' is greater than {0}MB.".FormatInvariant(megabytes), ex);
 			}
 		}

src/MySqlConnector/MySqlClient/ConnectionPool.cs

@@ -22,9 +22,8 @@ public async Task<MySqlSession> GetSessionAsync(IOBehavior ioBehavior, Cancellat
 
 			try
 			{
-				MySqlSession session;
 				// check for a pooled session
-				if (m_sessions.TryDequeue(out session))
+				if (m_sessions.TryDequeue(out var session))
 				{
 					if (session.PoolGeneration != m_generation || !await session.TryPingAsync(ioBehavior, cancellationToken).ConfigureAwait(false))
 					{
@@ -91,8 +90,7 @@ public async Task ClearAsync(IOBehavior ioBehavior, CancellationToken cancellati
 
 				try
 				{
-					MySqlSession session;
-					if (m_sessions.TryDequeue(out session))
+					if (m_sessions.TryDequeue(out var session))
 					{
 						if (session.PoolGeneration != m_generation)
 						{
@@ -122,8 +120,7 @@ public static ConnectionPool GetPool(ConnectionSettings cs)
 
 			var key = cs.ConnectionString;
 
-			ConnectionPool pool;
-			if (!s_pools.TryGetValue(key, out pool))
+			if (!s_pools.TryGetValue(key, out var pool))
 			{
 				pool = s_pools.GetOrAdd(cs.ConnectionString, newKey => new ConnectionPool(cs));
 			}

src/MySqlConnector/MySqlClient/MySqlCommand.cs

@@ -181,11 +181,7 @@ private void VerifyValid()
 				throw new MySqlException("There is already an open DataReader associated with this Connection which must be closed first.");
 		}
 
-		internal void ReaderClosed()
-		{
-			var executor = m_commandExecutor as StoredProcedureCommandExecutor;
-			executor?.SetParams();
-		}
+		internal void ReaderClosed() => (m_commandExecutor as StoredProcedureCommandExecutor)?.SetParams();
 
 		MySqlParameterCollection m_parameterCollection;
 		CommandType m_commandType;

src/MySqlConnector/MySqlClient/MySqlConnection.cs

@@ -14,15 +14,11 @@ namespace MySql.Data.MySqlClient
 	public sealed class MySqlConnection : DbConnection
 	{
 		public MySqlConnection()
+			: this("")
 		{
-			ConnectionString = "";
 		}
 
-		public MySqlConnection(string connectionString)
-			: this()
-		{
-			ConnectionString = connectionString;
-		}
+		public MySqlConnection(string connectionString) => ConnectionString = connectionString;
 
 		public new MySqlTransaction BeginTransaction() => (MySqlTransaction) base.BeginTransaction();
 
@@ -143,10 +139,7 @@ private async Task OpenAsync(IOBehavior ioBehavior, CancellationToken cancellati
 
 		public override string ConnectionString
 		{
-			get
-			{
-				return m_connectionStringBuilder.GetConnectionString(!m_hasBeenOpened || m_connectionSettings.PersistSecurityInfo);
-			}
+			get => m_connectionStringBuilder.GetConnectionString(!m_hasBeenOpened || m_connectionSettings.PersistSecurityInfo);
 			set
 			{
 				if (m_hasBeenOpened)
@@ -228,8 +221,7 @@ internal async Task<CachedProcedure> GetCachedProcedure(IOBehavior ioBehavior, s
 				m_cachedProcedures = new Dictionary<string, CachedProcedure>();
 
 			var normalized = NormalizedSchema.MustNormalize(name, Database);
-			CachedProcedure cachedProcedure;
-			if (!m_cachedProcedures.TryGetValue(normalized.FullyQualified, out cachedProcedure))
+			if (!m_cachedProcedures.TryGetValue(normalized.FullyQualified, out var cachedProcedure))
 			{
 				cachedProcedure = await CachedProcedure.FillAsync(ioBehavior, this, normalized.Schema, normalized.Component, cancellationToken).ConfigureAwait(false);
 				m_cachedProcedures[normalized.FullyQualified] = cachedProcedure;