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Changes to be able to use multiple datasets in a DbContext #26

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633b9b1
Changes to be able to use multiple datasets in a DbContext
hoffmannjanos Jan 19, 2022
19634a2
change in IsInterceptionEnabled to provide a read only list
hoffmannjanos Jan 24, 2022
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13 changes: 8 additions & 5 deletions src/EntityFramework.MemoryJoin/MemoryJoiner.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -77,11 +77,12 @@ public static IQueryable<T> FromLocalList<T>(this DbContext context, IList<T> da
/// <returns></returns>
public static IQueryable<T> FromLocalList<T>(this DbContext context, IList<T> data, Type queryClass, ValuesInjectionMethod method)
{
var tableName = EFHelper.GetTableName(context, queryClass);
if (MemoryJoinerInterceptor.IsInterceptionEnabled(
new[] { context }, out InterceptionOptions opts))
new[] {context}, false, out var opts) && opts.Any(x => x.QueryTableName == tableName))
{
throw new InvalidOperationException(
"Only one data set can be applied to single DbContext before actuall DB request is done");
"A table name (attribute on queryClass) can be applied only once to single DbContext before actual DB request is done");
}

var propMapping = allowedMappingDict.GetOrAdd(queryClass, MappingHelper.GetPropertyMappings);
Expand Down Expand Up @@ -117,20 +118,22 @@ static void PrepareInjection<T>(
Type queryClass,
ValuesInjectionMethod method)
{
var tableName = EFHelper.GetTableName(context, queryClass);

var opts = new InterceptionOptions
{
QueryTableName = EFHelper.GetTableName(context, queryClass),
QueryTableName = tableName,
ColumnNames = mapping.UserProperties.Keys.ToArray(),
Data = data
.Select(x => mapping.UserProperties.ToDictionary(y => y.Key, y => y.Value(x)))
.ToList(),
ContextType = context.GetType(),
ValuesInjectMethod = (ValuesInjectionMethodInternal)method,
KeyColumnName = mapping.KeyColumnName
KeyColumnName = mapping.KeyColumnName,
DynamicTableName = tableName
};

MemoryJoinerInterceptor.SetInterception(context, opts);
}

}
}
110 changes: 72 additions & 38 deletions src/EntityFramework.MemoryJoin/MemoryJoinerInterceptor.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -11,29 +11,47 @@ namespace EntityFramework.MemoryJoin
{
internal class MemoryJoinerInterceptor : IDbCommandInterceptor
{
private static readonly ConcurrentDictionary<DbContext, InterceptionOptions> InterceptionOptions =
new ConcurrentDictionary<DbContext, InterceptionOptions>();
private static readonly ConcurrentDictionary<DbContext, List<InterceptionOptions>> InterceptionOptions =
new ConcurrentDictionary<DbContext, List<InterceptionOptions>>();

private static readonly Object Locker = new object();

internal static void SetInterception(DbContext context, InterceptionOptions options)
{
InterceptionOptions[context] = options;
lock (Locker)
{
if (!InterceptionOptions.TryGetValue(context, out var opts))
{
opts = new List<InterceptionOptions>();
InterceptionOptions[context] = opts;
}

opts.Add(options);
}
}

internal static bool IsInterceptionEnabled(IEnumerable<DbContext> contexts, out InterceptionOptions options)
internal static bool IsInterceptionEnabled(IEnumerable<DbContext> contexts, bool removeContextOptions,
out IReadOnlyList<InterceptionOptions> options)
{
options = null;
using (var enumerator = contexts.GetEnumerator())
lock (Locker)
{
if (!enumerator.MoveNext()) return false;

var firstOne = enumerator.Current;
var result = firstOne != null &&
InterceptionOptions.TryGetValue(firstOne, out options) &&
!enumerator.MoveNext();
if (result)
InterceptionOptions.TryRemove(firstOne, out options);

return result;
options = null;
List<InterceptionOptions> internalOptions = null;
using (var enumerator = contexts.GetEnumerator())
{
if (!enumerator.MoveNext()) return false;

var firstOne = enumerator.Current;
var result = firstOne != null &&
InterceptionOptions.TryGetValue(firstOne, out internalOptions) &&
!enumerator.MoveNext();
options = internalOptions;

if (result && removeContextOptions)
InterceptionOptions.TryRemove(firstOne, out _);

return result;
}
}
}

Expand All @@ -43,7 +61,7 @@ public void NonQueryExecuted(DbCommand command, DbCommandInterceptionContext<int

public void NonQueryExecuting(DbCommand command, DbCommandInterceptionContext<int> interceptionContext)
{
if (IsInterceptionEnabled(interceptionContext.DbContexts, out var opts))
if (IsInterceptionEnabled(interceptionContext.DbContexts, true, out var opts))
ModifyQuery(command, opts);
}

Expand All @@ -53,7 +71,7 @@ public void ReaderExecuted(DbCommand command, DbCommandInterceptionContext<DbDat

public void ReaderExecuting(DbCommand command, DbCommandInterceptionContext<DbDataReader> interceptionContext)
{
if (IsInterceptionEnabled(interceptionContext.DbContexts, out var opts))
if (IsInterceptionEnabled(interceptionContext.DbContexts, true, out var opts))
ModifyQuery(command, opts);
}

Expand All @@ -63,34 +81,50 @@ public void ScalarExecuted(DbCommand command, DbCommandInterceptionContext<objec

public void ScalarExecuting(DbCommand command, DbCommandInterceptionContext<object> interceptionContext)
{
if (IsInterceptionEnabled(interceptionContext.DbContexts, out var opts))
if (IsInterceptionEnabled(interceptionContext.DbContexts, true, out var opts))
ModifyQuery(command, opts);
}

private static void ModifyQuery(DbCommand command, InterceptionOptions opts)
private static void ModifyQuery(DbCommand command, IReadOnlyList<InterceptionOptions> opts)
{
var tableNamePosition = command.CommandText.IndexOf(opts.QueryTableName, StringComparison.Ordinal);
if (tableNamePosition < 0)
return;
var sb = new StringBuilder(100);
sb.Append("WITH ");
var counter = 0;
var commandStart = 0;
foreach (var currentOptions in opts)
{
var tableNamePosition =
command.CommandText.IndexOf(currentOptions.QueryTableName, StringComparison.Ordinal);
if (tableNamePosition < 0)
continue;

var nextSpace = command.CommandText.IndexOf(' ', tableNamePosition);
var prevSpace = command.CommandText.LastIndexOf(' ', tableNamePosition);
var tableFullName = command.CommandText.Substring(prevSpace + 1, nextSpace - prevSpace - 1);
commandStart = command.CommandText.LastIndexOf(';', tableNamePosition) + 1;

command.CommandText = command.CommandText.Replace(tableFullName, opts.DynamicTableName);
var nextSpace = command.CommandText.IndexOf(' ', tableNamePosition);
var prevSpace = command.CommandText.LastIndexOf(' ', tableNamePosition);
var tableFullName = command.CommandText.Substring(prevSpace + 1, nextSpace - prevSpace - 1);

var sb = new StringBuilder(100);
sb.Append("WITH ").Append(opts.DynamicTableName).Append(" AS (").AppendLine();
MappingHelper.ComposeTableSql(
sb, opts,
command,
command.Parameters);
command.CommandText = command.CommandText.Replace(tableFullName, currentOptions.DynamicTableName);

if (counter > 0)
{
sb.AppendLine(",");
}

sb.Append(currentOptions.DynamicTableName).Append(" AS (").AppendLine();

sb.AppendLine();
sb.AppendLine(")");
sb.Append(command.CommandText);
MappingHelper.ComposeTableSql(
sb, currentOptions,
command,
command.Parameters);

sb.AppendLine();
sb.AppendLine(")");

counter++;
}

command.CommandText = sb.ToString();
command.CommandText = command.CommandText.Insert(commandStart, sb.ToString());
}
}
}
}