You've already forked linux-packaging-mono
504 lines
21 KiB
C#
504 lines
21 KiB
C#
using System;
|
|
using System.Collections.Generic;
|
|
using System.Diagnostics.CodeAnalysis;
|
|
|
|
namespace System.Data.Linq.SqlClient {
|
|
|
|
internal class SqlDeflator {
|
|
SqlValueDeflator vDeflator;
|
|
SqlColumnDeflator cDeflator;
|
|
SqlAliasDeflator aDeflator;
|
|
SqlTopSelectDeflator tsDeflator;
|
|
SqlDuplicateColumnDeflator dupColumnDeflator;
|
|
|
|
internal SqlDeflator() {
|
|
this.vDeflator = new SqlValueDeflator();
|
|
this.cDeflator = new SqlColumnDeflator();
|
|
this.aDeflator = new SqlAliasDeflator();
|
|
this.tsDeflator = new SqlTopSelectDeflator();
|
|
this.dupColumnDeflator = new SqlDuplicateColumnDeflator();
|
|
}
|
|
|
|
internal SqlNode Deflate(SqlNode node) {
|
|
node = this.vDeflator.Visit(node);
|
|
node = this.cDeflator.Visit(node);
|
|
node = this.aDeflator.Visit(node);
|
|
node = this.tsDeflator.Visit(node);
|
|
node = this.dupColumnDeflator.Visit(node);
|
|
return node;
|
|
}
|
|
|
|
// remove references to literal values
|
|
class SqlValueDeflator : SqlVisitor {
|
|
SelectionDeflator sDeflator;
|
|
bool isTopLevel = true;
|
|
|
|
internal SqlValueDeflator() {
|
|
this.sDeflator = new SelectionDeflator();
|
|
}
|
|
|
|
internal override SqlSelect VisitSelect(SqlSelect select) {
|
|
if (this.isTopLevel) {
|
|
select.Selection = sDeflator.VisitExpression(select.Selection);
|
|
}
|
|
return select;
|
|
}
|
|
|
|
internal override SqlExpression VisitSubSelect(SqlSubSelect ss) {
|
|
bool saveIsTopLevel = this.isTopLevel;
|
|
try {
|
|
return base.VisitSubSelect(ss);
|
|
}
|
|
finally {
|
|
this.isTopLevel = saveIsTopLevel;
|
|
}
|
|
}
|
|
|
|
class SelectionDeflator : SqlVisitor {
|
|
internal override SqlExpression VisitColumnRef(SqlColumnRef cref) {
|
|
SqlExpression literal = this.GetLiteralValue(cref);
|
|
if (literal != null) {
|
|
return literal;
|
|
}
|
|
return cref;
|
|
}
|
|
|
|
private SqlValue GetLiteralValue(SqlExpression expr) {
|
|
while (expr != null && expr.NodeType == SqlNodeType.ColumnRef) {
|
|
expr = ((SqlColumnRef)expr).Column.Expression;
|
|
}
|
|
return expr as SqlValue;
|
|
}
|
|
}
|
|
}
|
|
|
|
// remove unreferenced items in projection list
|
|
class SqlColumnDeflator : SqlVisitor {
|
|
Dictionary<SqlNode, SqlNode> referenceMap;
|
|
bool isTopLevel;
|
|
bool forceReferenceAll;
|
|
SqlAggregateChecker aggregateChecker;
|
|
|
|
internal SqlColumnDeflator() {
|
|
this.referenceMap = new Dictionary<SqlNode, SqlNode>();
|
|
this.aggregateChecker = new SqlAggregateChecker();
|
|
this.isTopLevel = true;
|
|
}
|
|
|
|
internal override SqlExpression VisitColumnRef(SqlColumnRef cref) {
|
|
this.referenceMap[cref.Column] = cref.Column;
|
|
return cref;
|
|
}
|
|
|
|
internal override SqlExpression VisitScalarSubSelect(SqlSubSelect ss) {
|
|
bool saveIsTopLevel = this.isTopLevel;
|
|
this.isTopLevel = false;
|
|
bool saveForceReferenceAll = this.forceReferenceAll;
|
|
this.forceReferenceAll = true;
|
|
try {
|
|
return base.VisitScalarSubSelect(ss);
|
|
}
|
|
finally {
|
|
this.isTopLevel = saveIsTopLevel;
|
|
this.forceReferenceAll = saveForceReferenceAll;
|
|
}
|
|
}
|
|
|
|
internal override SqlExpression VisitExists(SqlSubSelect ss) {
|
|
bool saveIsTopLevel = this.isTopLevel;
|
|
this.isTopLevel = false;
|
|
try {
|
|
return base.VisitExists(ss);
|
|
}
|
|
finally {
|
|
this.isTopLevel = saveIsTopLevel;
|
|
}
|
|
}
|
|
|
|
internal override SqlNode VisitUnion(SqlUnion su) {
|
|
bool saveForceReferenceAll = this.forceReferenceAll;
|
|
this.forceReferenceAll = true;
|
|
su.Left = this.Visit(su.Left);
|
|
su.Right = this.Visit(su.Right);
|
|
this.forceReferenceAll = saveForceReferenceAll;
|
|
return su;
|
|
}
|
|
|
|
internal override SqlSelect VisitSelect(SqlSelect select) {
|
|
bool saveForceReferenceAll = this.forceReferenceAll;
|
|
this.forceReferenceAll = false;
|
|
bool saveIsTopLevel = this.isTopLevel;
|
|
|
|
try {
|
|
if (this.isTopLevel) {
|
|
// top-level projection references columns!
|
|
select.Selection = this.VisitExpression(select.Selection);
|
|
}
|
|
this.isTopLevel = false;
|
|
|
|
for (int i = select.Row.Columns.Count - 1; i >= 0; i--) {
|
|
SqlColumn c = select.Row.Columns[i];
|
|
|
|
bool safeToRemove =
|
|
!saveForceReferenceAll
|
|
&& !this.referenceMap.ContainsKey(c)
|
|
// don't remove anything from a distinct select (except maybe a literal value) since it would change the meaning of the comparison
|
|
&& !select.IsDistinct
|
|
// don't remove an aggregate expression that may be the only expression that forces the grouping (since it would change the cardinality of the results)
|
|
&& !(select.GroupBy.Count == 0 && this.aggregateChecker.HasAggregates(c.Expression));
|
|
|
|
if (safeToRemove) {
|
|
select.Row.Columns.RemoveAt(i);
|
|
}
|
|
else {
|
|
this.VisitExpression(c.Expression);
|
|
}
|
|
}
|
|
|
|
select.Top = this.VisitExpression(select.Top);
|
|
for (int i = select.OrderBy.Count - 1; i >= 0; i--) {
|
|
select.OrderBy[i].Expression = this.VisitExpression(select.OrderBy[i].Expression);
|
|
}
|
|
|
|
select.Having = this.VisitExpression(select.Having);
|
|
for (int i = select.GroupBy.Count - 1; i >= 0; i--) {
|
|
select.GroupBy[i] = this.VisitExpression(select.GroupBy[i]);
|
|
}
|
|
|
|
select.Where = this.VisitExpression(select.Where);
|
|
select.From = this.VisitSource(select.From);
|
|
}
|
|
finally {
|
|
this.isTopLevel = saveIsTopLevel;
|
|
this.forceReferenceAll = saveForceReferenceAll;
|
|
}
|
|
|
|
return select;
|
|
}
|
|
|
|
internal override SqlSource VisitJoin(SqlJoin join) {
|
|
join.Condition = this.VisitExpression(join.Condition);
|
|
join.Right = this.VisitSource(join.Right);
|
|
join.Left = this.VisitSource(join.Left);
|
|
return join;
|
|
}
|
|
|
|
internal override SqlNode VisitLink(SqlLink link) {
|
|
// don't visit expansion...
|
|
for (int i = 0, n = link.KeyExpressions.Count; i < n; i++) {
|
|
link.KeyExpressions[i] = this.VisitExpression(link.KeyExpressions[i]);
|
|
}
|
|
return link;
|
|
}
|
|
}
|
|
|
|
class SqlColumnEqualizer : SqlVisitor {
|
|
Dictionary<SqlColumn, SqlColumn> map;
|
|
|
|
internal SqlColumnEqualizer() {
|
|
}
|
|
|
|
internal void BuildEqivalenceMap(SqlSource scope) {
|
|
this.map = new Dictionary<SqlColumn, SqlColumn>();
|
|
this.Visit(scope);
|
|
}
|
|
|
|
internal bool AreEquivalent(SqlExpression e1, SqlExpression e2) {
|
|
if (SqlComparer.AreEqual(e1, e2))
|
|
return true;
|
|
|
|
SqlColumnRef cr1 = e1 as SqlColumnRef;
|
|
SqlColumnRef cr2 = e2 as SqlColumnRef;
|
|
|
|
if (cr1 != null && cr2 != null) {
|
|
SqlColumn c1 = cr1.GetRootColumn();
|
|
SqlColumn c2 = cr2.GetRootColumn();
|
|
SqlColumn r;
|
|
return this.map.TryGetValue(c1, out r) && r == c2;
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
internal override SqlSource VisitJoin(SqlJoin join) {
|
|
base.VisitJoin(join);
|
|
if (join.Condition != null) {
|
|
this.CheckJoinCondition(join.Condition);
|
|
}
|
|
return join;
|
|
}
|
|
|
|
internal override SqlSelect VisitSelect(SqlSelect select) {
|
|
base.VisitSelect(select);
|
|
if (select.Where != null) {
|
|
this.CheckJoinCondition(select.Where);
|
|
}
|
|
return select;
|
|
}
|
|
|
|
[SuppressMessage("Microsoft.Performance", "CA1800:DoNotCastUnnecessarily", Justification="Microsoft: Cast is dependent on node type and casts do not happen unecessarily in a single code path.")]
|
|
private void CheckJoinCondition(SqlExpression expr) {
|
|
switch (expr.NodeType) {
|
|
case SqlNodeType.And: {
|
|
SqlBinary b = (SqlBinary)expr;
|
|
CheckJoinCondition(b.Left);
|
|
CheckJoinCondition(b.Right);
|
|
break;
|
|
}
|
|
case SqlNodeType.EQ:
|
|
case SqlNodeType.EQ2V: {
|
|
SqlBinary b = (SqlBinary)expr;
|
|
SqlColumnRef crLeft = b.Left as SqlColumnRef;
|
|
SqlColumnRef crRight = b.Right as SqlColumnRef;
|
|
if (crLeft != null && crRight != null) {
|
|
SqlColumn cLeft = crLeft.GetRootColumn();
|
|
SqlColumn cRight = crRight.GetRootColumn();
|
|
this.map[cLeft] = cRight;
|
|
this.map[cRight] = cLeft;
|
|
}
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
|
|
internal override SqlExpression VisitSubSelect(SqlSubSelect ss) {
|
|
return ss;
|
|
}
|
|
}
|
|
|
|
// remove redundant/trivial aliases
|
|
class SqlAliasDeflator : SqlVisitor {
|
|
Dictionary<SqlAlias, SqlAlias> removedMap;
|
|
|
|
internal SqlAliasDeflator() {
|
|
this.removedMap = new Dictionary<SqlAlias, SqlAlias>();
|
|
}
|
|
|
|
internal override SqlExpression VisitAliasRef(SqlAliasRef aref) {
|
|
SqlAlias alias = aref.Alias;
|
|
SqlAlias value;
|
|
if (this.removedMap.TryGetValue(alias, out value)) {
|
|
throw Error.InvalidReferenceToRemovedAliasDuringDeflation();
|
|
}
|
|
return aref;
|
|
}
|
|
|
|
internal override SqlExpression VisitColumnRef(SqlColumnRef cref) {
|
|
if (cref.Column.Alias != null && this.removedMap.ContainsKey(cref.Column.Alias)) {
|
|
SqlColumnRef c = cref.Column.Expression as SqlColumnRef;
|
|
if (c != null) {
|
|
//The following code checks for cases where there are differences between the type returned
|
|
//by a ColumnRef and the column that refers to it. This situation can occur when conversions
|
|
//are optimized out of the SQL node tree. As mentioned in the SetClrType comments this is not
|
|
//an operation that can have adverse effects and should only be used in limited cases, such as
|
|
//this one.
|
|
if (c.ClrType != cref.ClrType) {
|
|
c.SetClrType(cref.ClrType);
|
|
return this.VisitColumnRef(c);
|
|
}
|
|
}
|
|
return c;
|
|
}
|
|
return cref;
|
|
}
|
|
|
|
internal override SqlSource VisitSource(SqlSource node) {
|
|
node = (SqlSource)this.Visit(node);
|
|
SqlAlias alias = node as SqlAlias;
|
|
if (alias != null) {
|
|
SqlSelect sel = alias.Node as SqlSelect;
|
|
if (sel != null && this.IsTrivialSelect(sel)) {
|
|
this.removedMap[alias] = alias;
|
|
node = sel.From;
|
|
}
|
|
}
|
|
return node;
|
|
}
|
|
|
|
internal override SqlSource VisitJoin(SqlJoin join) {
|
|
base.VisitJoin(join);
|
|
switch (join.JoinType) {
|
|
case SqlJoinType.Cross:
|
|
case SqlJoinType.Inner:
|
|
// reducing either side would effect cardinality of results
|
|
break;
|
|
case SqlJoinType.LeftOuter:
|
|
case SqlJoinType.CrossApply:
|
|
case SqlJoinType.OuterApply:
|
|
// may reduce to left if no references to the right
|
|
if (this.HasEmptySource(join.Right)) {
|
|
SqlAlias a = (SqlAlias)join.Right;
|
|
this.removedMap[a] = a;
|
|
return join.Left;
|
|
}
|
|
break;
|
|
}
|
|
return join;
|
|
}
|
|
|
|
private bool IsTrivialSelect(SqlSelect select) {
|
|
if (select.OrderBy.Count != 0 ||
|
|
select.GroupBy.Count != 0 ||
|
|
select.Having != null ||
|
|
select.Top != null ||
|
|
select.IsDistinct ||
|
|
select.Where != null)
|
|
return false;
|
|
return this.HasTrivialSource(select.From) && this.HasTrivialProjection(select);
|
|
}
|
|
|
|
private bool HasTrivialSource(SqlSource node) {
|
|
SqlJoin join = node as SqlJoin;
|
|
if (join != null) {
|
|
return this.HasTrivialSource(join.Left) &&
|
|
this.HasTrivialSource(join.Right);
|
|
}
|
|
return node is SqlAlias;
|
|
}
|
|
|
|
[SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification="Unknown reason.")]
|
|
private bool HasTrivialProjection(SqlSelect select) {
|
|
foreach (SqlColumn c in select.Row.Columns) {
|
|
if (c.Expression != null && c.Expression.NodeType != SqlNodeType.ColumnRef) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
[SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification="Unknown reason.")]
|
|
private bool HasEmptySource(SqlSource node) {
|
|
SqlAlias alias = node as SqlAlias;
|
|
if (alias == null) return false;
|
|
SqlSelect sel = alias.Node as SqlSelect;
|
|
if (sel == null) return false;
|
|
return sel.Row.Columns.Count == 0 &&
|
|
sel.From == null &&
|
|
sel.Where == null &&
|
|
sel.GroupBy.Count == 0 &&
|
|
sel.Having == null &&
|
|
sel.OrderBy.Count == 0;
|
|
}
|
|
}
|
|
|
|
// remove duplicate columns from order by and group by lists
|
|
class SqlDuplicateColumnDeflator : SqlVisitor
|
|
{
|
|
SqlColumnEqualizer equalizer = new SqlColumnEqualizer();
|
|
|
|
internal override SqlSelect VisitSelect(SqlSelect select) {
|
|
select.From = this.VisitSource(select.From);
|
|
select.Where = this.VisitExpression(select.Where);
|
|
for (int i = 0, n = select.GroupBy.Count; i < n; i++)
|
|
{
|
|
select.GroupBy[i] = this.VisitExpression(select.GroupBy[i]);
|
|
}
|
|
// remove duplicate group expressions
|
|
for (int i = select.GroupBy.Count - 1; i >= 0; i--)
|
|
{
|
|
for (int j = i - 1; j >= 0; j--)
|
|
{
|
|
if (SqlComparer.AreEqual(select.GroupBy[i], select.GroupBy[j]))
|
|
{
|
|
select.GroupBy.RemoveAt(i);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
select.Having = this.VisitExpression(select.Having);
|
|
for (int i = 0, n = select.OrderBy.Count; i < n; i++)
|
|
{
|
|
select.OrderBy[i].Expression = this.VisitExpression(select.OrderBy[i].Expression);
|
|
}
|
|
// remove duplicate order expressions
|
|
if (select.OrderBy.Count > 0)
|
|
{
|
|
this.equalizer.BuildEqivalenceMap(select.From);
|
|
|
|
for (int i = select.OrderBy.Count - 1; i >= 0; i--)
|
|
{
|
|
for (int j = i - 1; j >= 0; j--)
|
|
{
|
|
if (this.equalizer.AreEquivalent(select.OrderBy[i].Expression, select.OrderBy[j].Expression))
|
|
{
|
|
select.OrderBy.RemoveAt(i);
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
select.Top = this.VisitExpression(select.Top);
|
|
select.Row = (SqlRow)this.Visit(select.Row);
|
|
select.Selection = this.VisitExpression(select.Selection);
|
|
return select;
|
|
}
|
|
}
|
|
|
|
// if the top level select is simply a reprojection of the subquery, then remove it,
|
|
// pushing any distinct names down
|
|
class SqlTopSelectDeflator : SqlVisitor {
|
|
|
|
internal override SqlSelect VisitSelect(SqlSelect select) {
|
|
if (IsTrivialSelect(select)) {
|
|
SqlSelect aselect = (SqlSelect)((SqlAlias)select.From).Node;
|
|
// build up a column map, so we can rewrite the top-level selection expression
|
|
Dictionary<SqlColumn, SqlColumnRef> map = new Dictionary<SqlColumn, SqlColumnRef>();
|
|
foreach (SqlColumn c in select.Row.Columns) {
|
|
SqlColumnRef cref = (SqlColumnRef)c.Expression;
|
|
map.Add(c, cref);
|
|
// push the interesting column names down (non null)
|
|
if (!string.IsNullOrEmpty(c.Name)) {
|
|
cref.Column.Name = c.Name;
|
|
}
|
|
}
|
|
aselect.Selection = new ColumnMapper(map).VisitExpression(select.Selection);
|
|
return aselect;
|
|
}
|
|
return select;
|
|
}
|
|
|
|
private bool IsTrivialSelect(SqlSelect select) {
|
|
if (select.OrderBy.Count != 0 ||
|
|
select.GroupBy.Count != 0 ||
|
|
select.Having != null ||
|
|
select.Top != null ||
|
|
select.IsDistinct ||
|
|
select.Where != null)
|
|
return false;
|
|
return this.HasTrivialSource(select.From) && this.HasTrivialProjection(select);
|
|
}
|
|
|
|
[SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification="Unknown reason.")]
|
|
private bool HasTrivialSource(SqlSource node) {
|
|
SqlAlias alias = node as SqlAlias;
|
|
if (alias == null) return false;
|
|
return alias.Node is SqlSelect;
|
|
}
|
|
|
|
[SuppressMessage("Microsoft.Performance", "CA1822:MarkMembersAsStatic", Justification="Unknown reason.")]
|
|
private bool HasTrivialProjection(SqlSelect select) {
|
|
foreach (SqlColumn c in select.Row.Columns) {
|
|
if (c.Expression != null && c.Expression.NodeType != SqlNodeType.ColumnRef) {
|
|
return false;
|
|
}
|
|
}
|
|
return true;
|
|
}
|
|
|
|
class ColumnMapper : SqlVisitor {
|
|
Dictionary<SqlColumn, SqlColumnRef> map;
|
|
internal ColumnMapper(Dictionary<SqlColumn, SqlColumnRef> map) {
|
|
this.map = map;
|
|
}
|
|
internal override SqlExpression VisitColumnRef(SqlColumnRef cref) {
|
|
SqlColumnRef mapped;
|
|
if (this.map.TryGetValue(cref.Column, out mapped)) {
|
|
return mapped;
|
|
}
|
|
return cref;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
}
|