add SqlInsertValuesCollection.cs

Author: SergeiPavlov

Orm/Xtensive.Orm/Sql/Dml/Statements/SqlInsertValuesCollection.cs

@@ -0,0 +1,136 @@
+// Copyright (C) 2023 Xtensive LLC.
+// This code is distributed under MIT license terms.
+// See the License.txt file in the project root for more information.
+
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using Xtensive.Core;
+
+namespace Xtensive.Sql.Dml.Collections
+{
+  /// <summary>
+  /// Collection of values of <see cref="SqlInsert"/>.
+  /// </summary>
+  public sealed class SqlInsertValuesCollection : IReadOnlyList<SqlRow>
+  {
+    private IReadOnlyList<SqlColumn> columns;
+    private List<SqlRow> rows = new();
+
+    /// <summary>
+    /// The columns collection has values for.
+    /// </summary>
+    public IReadOnlyList<SqlColumn> Columns => columns ?? Array.Empty<SqlColumn>();
+
+    /// <summary>
+    /// Count of rows.
+    /// </summary>
+    public int Count => rows.Count;
+
+    /// <summary>
+    /// Gets row by index.
+    /// </summary>
+    /// <param name="index"></param>
+    /// <returns></returns>
+    public SqlRow this[int index] => rows[index];
+
+    /// <summary>
+    /// Adds column-to-value mapped collection of values as row.
+    /// </summary>
+    /// <param name="row">column-to-value mapped collection of values</param>
+    /// <exception cref="ArgumentNullException"><paramref name="row"/> value is null.</exception>
+    /// <exception cref="ArgumentException">Count of values between already added rows and <paramref name="row"/>
+    /// -or- particular column in <paramref name="row"/> is not presented in already added rows
+    /// -or- <paramref name="row"/> is empty.</exception>
+    public void Add(Dictionary<SqlColumn, SqlExpression> row)
+    {
+#if NET6_0_OR_GREATER
+      ArgumentNullException.ThrowIfNull(row, nameof(row));
+#else
+      ArgumentValidator.EnsureArgumentNotNull(row, nameof(row));
+#endif
+      if (row.Count == 0) {
+        throw new ArgumentException("Empty row is not allowed.");
+      }
+
+      if (rows.Count == 0) {
+        // save columns order as header for further rows to match;
+        columns = row.Keys.ToList();
+        rows.Add(SqlDml.Row(row.Values.ToList()));
+      }
+      else {
+        if (columns.Count != row.Count)
+          throw new ArgumentException("Inconsistent row length.");
+        if (row.Keys.SequenceEqual(columns)) {
+          //fast addition
+          rows.Add(SqlDml.Row(row.Values.ToList()));
+        }
+        else {
+          //re-arrange values to be the same order
+          //and also make sure all columns exist
+          var rowList = new List<SqlExpression>();
+          foreach (var column in columns) {
+            if (row.TryGetValue(column, out var value)) {
+              rowList.Add(value);
+            }
+            else {
+              throw new ArgumentException(string.Format("There is no mentioning of column '{0}' in previously added rows.", column.Name));
+            }
+          }
+
+          rows.Add(SqlDml.Row(rowList));
+        }
+      }
+    }
+
+    /// <summary>
+    /// Removes row by index.
+    /// </summary>
+    /// <param name="index">The index of row to remove.</param>
+    public void RemoveAt(int index)
+    {
+      rows.RemoveAt(index);
+      if (rows.Count == 0) {
+        columns = null;
+      }
+    }
+
+    /// <summary>
+    /// Clears rows and columns.
+    /// </summary>
+    public void Clear()
+    {
+      rows = new List<SqlRow>();
+      columns = null;
+    }
+
+    /// <inheritdoc/>
+    public IEnumerator<SqlRow> GetEnumerator() => rows.GetEnumerator();
+
+    /// <inheritdoc/>
+    IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
+
+    internal SqlInsertValuesCollection Clone(SqlNodeCloneContext context)
+    {
+      var clone = new SqlInsertValuesCollection();
+
+      if (rows.Count == 0) {
+        return clone;
+      }
+
+      var clonedList = new List<SqlColumn>(columns.Count);
+      foreach (var oldColumn in columns) {
+        clonedList.Add((SqlColumn) context.NodeMapping[oldColumn]);
+      }
+      clone.columns = clonedList;
+
+      clone.rows = new List<SqlRow>(rows.Count);
+      foreach(var oldRow in rows) {
+        clone.rows.Add((SqlRow) oldRow.Clone());
+      }
+
+      return clone;
+    }
+  }
+}