|
//---------------------------------------------------------------------
// <copyright file="UpdateTranslator.TableChangeProcessor.cs" company="Microsoft">
// Copyright (c) Microsoft Corporation. All rights reserved.
// </copyright>
//
// @owner Microsoft
// @backupOwner Microsoft
//---------------------------------------------------------------------
namespace System.Data.Mapping.Update.Internal
{
using System.Collections.Generic;
using System.Data.Common;
using System.Data.Common.Utils;
using System.Data.Entity;
using System.Data.Metadata.Edm;
using System.Diagnostics;
using System.Linq;
/// <summary>
/// Processes changes applying to a table by merging inserts and deletes into updates
/// where appropriate.
/// </summary>
/// <remarks>
/// This class is essentially responsible for identifying inserts, deletes
/// and updates in a particular table based on the <see cref="ChangeNode" />
/// produced by value propagation w.r.t. the update mapping view for that table.
/// Assumes the change node includes at most a single insert and at most a single delete
/// for a given key (where we have both, the change is treated as an update).
/// </remarks>
internal class TableChangeProcessor
{
#region Constructors
/// <summary>
/// Constructs processor based on the contents of a change node.
/// </summary>
/// <param name="table">Table for which changes are being processed.</param>
internal TableChangeProcessor(EntitySet table)
{
EntityUtil.CheckArgumentNull(table, "table");
m_table = table;
// cache information about table key
m_keyOrdinals = InitializeKeyOrdinals(table);
}
#endregion
#region Fields
private readonly EntitySet m_table;
private readonly int[] m_keyOrdinals;
#endregion
#region Properties
/// <summary>
/// Gets metadata for the table being modified.
/// </summary>
internal EntitySet Table
{
get { return m_table; }
}
/// <summary>
/// Gets a map from column ordinal to property descriptions for columns that are components of the table's
/// primary key.
/// </summary>
internal int[] KeyOrdinals { get { return m_keyOrdinals; } }
#endregion
#region Methods
// Determines whether the given ordinal position in the property list
// for this table is a key value.
internal bool IsKeyProperty(int propertyOrdinal)
{
foreach (int keyOrdinal in m_keyOrdinals)
{
if (propertyOrdinal == keyOrdinal) { return true; }
}
return false;
}
// Determines which column ordinals in the table are part of the key.
private static int[] InitializeKeyOrdinals(EntitySet table)
{
EntityType tableType = table.ElementType;
IList<EdmMember> keyMembers = tableType.KeyMembers;
IBaseList<EdmMember> members = TypeHelpers.GetAllStructuralMembers(tableType);
int[] keyOrdinals = new int[keyMembers.Count];
for (int keyMemberIndex = 0; keyMemberIndex < keyMembers.Count; keyMemberIndex++)
{
EdmMember keyMember = keyMembers[keyMemberIndex];
keyOrdinals[keyMemberIndex] = members.IndexOf(keyMember);
Debug.Assert(keyOrdinals[keyMemberIndex] >= 0 && keyOrdinals[keyMemberIndex] < members.Count,
"an EntityType key member must also be a member of the entity type");
}
return keyOrdinals;
}
// Processes all insert and delete requests in the table's <see cref="ChangeNode" />. Inserts
// and deletes with the same key are merged into updates.
internal List<UpdateCommand> CompileCommands(ChangeNode changeNode, UpdateCompiler compiler)
{
Set<CompositeKey> keys = new Set<CompositeKey>(compiler.m_translator.KeyComparer);
// Retrieve all delete results (original values) and insert results (current values) while
// populating a set of all row keys. The set contains a single key per row.
Dictionary<CompositeKey, PropagatorResult> deleteResults = ProcessKeys(compiler, changeNode.Deleted, keys);
Dictionary<CompositeKey, PropagatorResult> insertResults = ProcessKeys(compiler, changeNode.Inserted, keys);
List<UpdateCommand> commands = new List<UpdateCommand>(deleteResults.Count + insertResults.Count);
// Examine each row key to see if the row is being deleted, inserted or updated
foreach (CompositeKey key in keys)
{
PropagatorResult deleteResult;
PropagatorResult insertResult;
bool hasDelete = deleteResults.TryGetValue(key, out deleteResult);
bool hasInsert = insertResults.TryGetValue(key, out insertResult);
Debug.Assert(hasDelete || hasInsert, "(update/TableChangeProcessor) m_keys must not contain a value " +
"if there is no corresponding insert or delete");
try
{
if (!hasDelete)
{
// this is an insert
commands.Add(compiler.BuildInsertCommand(insertResult, this));
}
else if (!hasInsert)
{
// this is a delete
commands.Add(compiler.BuildDeleteCommand(deleteResult, this));
}
else
{
// this is an update because it has both a delete result and an insert result
UpdateCommand updateCommand = compiler.BuildUpdateCommand(deleteResult, insertResult, this);
if (null != updateCommand)
{
// if null is returned, it means it is a no-op update
commands.Add(updateCommand);
}
}
}
catch (Exception e)
{
if (UpdateTranslator.RequiresContext(e))
{
// collect state entries in scope for the current compilation
List<IEntityStateEntry> stateEntries = new List<IEntityStateEntry>();
if (null != deleteResult)
{
stateEntries.AddRange(SourceInterpreter.GetAllStateEntries(
deleteResult, compiler.m_translator, m_table));
}
if (null != insertResult)
{
stateEntries.AddRange(SourceInterpreter.GetAllStateEntries(
insertResult, compiler.m_translator, m_table));
}
throw EntityUtil.Update(System.Data.Entity.Strings.Update_GeneralExecutionException,
e, stateEntries);
}
throw;
}
}
return commands;
}
// Determines key values for a list of changes. Side effect: populates <see cref="keys" /> which
// includes an entry for every key involved in a change.
private Dictionary<CompositeKey, PropagatorResult> ProcessKeys(UpdateCompiler compiler, List<PropagatorResult> changes, Set<CompositeKey> keys)
{
Dictionary<CompositeKey, PropagatorResult> map = new Dictionary<CompositeKey, PropagatorResult>(
compiler.m_translator.KeyComparer);
foreach (PropagatorResult change in changes)
{
// Reassign change to row since we cannot modify iteration variable
PropagatorResult row = change;
CompositeKey key = new CompositeKey(GetKeyConstants(row));
// Make sure we aren't inserting another row with the same key
PropagatorResult other;
if (map.TryGetValue(key, out other))
{
DiagnoseKeyCollision(compiler, change, key, other);
}
map.Add(key, row);
keys.Add(key);
}
return map;
}
[System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Security", "CA2140:TransparentMethodsMustNotReferenceCriticalCode", Justification = "Based on Bug VSTS Pioneer #433188: IsVisibleOutsideAssembly is wrong on generic instantiations.")]
private void DiagnoseKeyCollision(UpdateCompiler compiler, PropagatorResult change, CompositeKey key, PropagatorResult other)
{
KeyManager keyManager = compiler.m_translator.KeyManager;
CompositeKey otherKey = new CompositeKey(GetKeyConstants(other));
// determine if the conflict is due to shared principal key values
bool sharedPrincipal = true;
for (int i = 0; sharedPrincipal && i < key.KeyComponents.Length; i++)
{
int identifier1 = key.KeyComponents[i].Identifier;
int identifier2 = otherKey.KeyComponents[i].Identifier;
if (!keyManager.GetPrincipals(identifier1).Intersect(keyManager.GetPrincipals(identifier2)).Any())
{
sharedPrincipal = false;
}
}
if (sharedPrincipal)
{
// if the duplication is due to shared principals, there is a duplicate key exception
var stateEntries = SourceInterpreter.GetAllStateEntries(change, compiler.m_translator, m_table)
.Concat(SourceInterpreter.GetAllStateEntries(other, compiler.m_translator, m_table));
throw EntityUtil.Update(Strings.Update_DuplicateKeys, null, stateEntries);
}
else
{
// if there are no shared principals, it implies that common dependents are the problem
HashSet<IEntityStateEntry> commonDependents = null;
foreach (PropagatorResult keyValue in key.KeyComponents.Concat(otherKey.KeyComponents))
{
var dependents = new HashSet<IEntityStateEntry>();
foreach (int dependentId in keyManager.GetDependents(keyValue.Identifier))
{
PropagatorResult dependentResult;
if (keyManager.TryGetIdentifierOwner(dependentId, out dependentResult) &&
null != dependentResult.StateEntry)
{
dependents.Add(dependentResult.StateEntry);
}
}
if (null == commonDependents)
{
commonDependents = new HashSet<IEntityStateEntry>(dependents);
}
else
{
commonDependents.IntersectWith(dependents);
}
}
// to ensure the exception shape is consistent with constraint violations discovered while processing
// commands (a more conventional scenario in which different tables are contributing principal values)
// wrap a DataConstraintException in an UpdateException
throw EntityUtil.Update(Strings.Update_GeneralExecutionException,
EntityUtil.Constraint(Strings.Update_ReferentialConstraintIntegrityViolation), commonDependents);
}
}
// Extracts key constants from the given row.
private PropagatorResult[] GetKeyConstants(PropagatorResult row)
{
PropagatorResult[] keyConstants = new PropagatorResult[m_keyOrdinals.Length];
for (int i = 0; i < m_keyOrdinals.Length; i++)
{
PropagatorResult constant = row.GetMemberValue(m_keyOrdinals[i]);
keyConstants[i] = constant;
}
return keyConstants;
}
#endregion
}
}
|