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Diffstat (limited to 'lib/VNLib.Plugins.Extensions.Data/src/SQL/EnumerableTable.cs')
| -rw-r--r-- | lib/VNLib.Plugins.Extensions.Data/src/SQL/EnumerableTable.cs | 118 |
1 files changed, 0 insertions, 118 deletions
diff --git a/lib/VNLib.Plugins.Extensions.Data/src/SQL/EnumerableTable.cs b/lib/VNLib.Plugins.Extensions.Data/src/SQL/EnumerableTable.cs deleted file mode 100644 index 0d289b6..0000000 --- a/lib/VNLib.Plugins.Extensions.Data/src/SQL/EnumerableTable.cs +++ /dev/null @@ -1,118 +0,0 @@ -/* -* Copyright (c) 2022 Vaughn Nugent -* -* Library: VNLib -* Package: VNLib.Plugins.Extensions.Data -* File: EnumerableTable.cs -* -* EnumerableTable.cs is part of VNLib.Plugins.Extensions.Data which is part of the larger -* VNLib collection of libraries and utilities. -* -* VNLib.Plugins.Extensions.Data is free software: you can redistribute it and/or modify -* it under the terms of the GNU Affero General Public License as -* published by the Free Software Foundation, either version 3 of the -* License, or (at your option) any later version. -* -* VNLib.Plugins.Extensions.Data is distributed in the hope that it will be useful, -* but WITHOUT ANY WARRANTY; without even the implied warranty of -* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the -* GNU Affero General Public License for more details. -* -* You should have received a copy of the GNU Affero General Public License -* along with this program. If not, see https://www.gnu.org/licenses/. -*/ - -using System; -using System.Data; -using System.Threading; -using System.Data.Common; -using System.Threading.Tasks; -using System.Collections.Generic; - -namespace VNLib.Plugins.Extensions.Data.SQL -{ - /// <summary> - /// A base class for client side async enumerable SQL queries - /// </summary> - /// <typeparam name="T">The entity type</typeparam> - public abstract class EnumerableTable<T> : TableManager, IAsyncEnumerable<T> - { - const string DEFAULT_ENUM_STATMENT = "SELECT *\r\nFROM @table\r\n;"; - - public EnumerableTable(Func<DbConnection> factory, string tableName) : base(factory, tableName) - { - //Build the default select all statment - Enumerate = DEFAULT_ENUM_STATMENT.Replace("@table", tableName); - } - public EnumerableTable(Func<DbConnection> factory) : base(factory) - { } - - /// <summary> - /// The command that will be run against the database to return rows for enumeration - /// </summary> - protected string Enumerate { get; set; } - - /// <summary> - /// The isolation level to use when creating the transaction during enumerations - /// </summary> - protected IsolationLevel TransactionIsolationLevel { get; set; } = IsolationLevel.ReadUncommitted; - - IAsyncEnumerator<T> IAsyncEnumerable<T>.GetAsyncEnumerator(CancellationToken cancellationToken) - { - return GetAsyncEnumerator(cancellationToken: cancellationToken); - } - - /// <summary> - /// Transforms a row from the <paramref name="reader"/> into the item type - /// to be returned when yielded. - /// </summary> - /// <param name="reader">The reader to get the item data from</param> - /// <param name="cancellationToken">A token to cancel the operation</param> - /// <returns>A task that returns the transformed item</returns> - /// <remarks>The <paramref name="reader"/> position is set before this method is invoked</remarks> - protected abstract Task<T> GetItemAsync(DbDataReader reader, CancellationToken cancellationToken); - /// <summary> - /// Invoked when an item is no longer in the enumerator scope, in the enumeration process. - /// </summary> - /// <param name="item">The item to cleanup</param> - /// <param name="cancellationToken">A token to cancel the operation</param> - /// <returns>A ValueTask that represents the cleanup process</returns> - protected abstract ValueTask CleanupItemAsync(T item, CancellationToken cancellationToken); - - /// <summary> - /// Gets an <see cref="IAsyncEnumerator{T}"/> to enumerate items within the backing store. - /// </summary> - /// <param name="closeItems">Cleanup items after each item is enumerated and the enumeration scope has - /// returned to the enumerator</param> - /// <param name="cancellationToken">A token to cancel the enumeration</param> - /// <returns>A <see cref="IAsyncEnumerator{T}"/> to enumerate records within the store</returns> - public virtual async IAsyncEnumerator<T> GetAsyncEnumerator(bool closeItems = true, CancellationToken cancellationToken = default) - { - await using DbConnection db = GetConnection(); - await db.OpenAsync(cancellationToken); - await using DbTransaction transaction = await db.BeginTransactionAsync(cancellationToken); - //Start the enumeration command - await using DbCommand cmd = db.CreateTextCommand(Enumerate, transaction); - await cmd.PrepareAsync(cancellationToken); - await using DbDataReader reader = await cmd.ExecuteReaderAsync(cancellationToken); - //loop through results and transform each element - while (reader.Read()) - { - //get the item - T item = await GetItemAsync(reader, cancellationToken); - try - { - yield return item; - } - finally - { - if (closeItems) - { - //Cleanup the item - await CleanupItemAsync(item, cancellationToken); - } - } - } - } - } -}
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