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Minor optimizations in ExpressionStringBuilder (#512)
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* Don't append single chars via strings
* Avoid unnecessary `StringBuilder` instantiations
* Apply optimizations inside `AppendDisplayName`
* Reduce lambda usage
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@stakx
stakx authored Nov 3, 2017
1 parent 354840d commit f2e0246
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Showing 2 changed files with 88 additions and 95 deletions.
12 changes: 2 additions & 10 deletions Source/ExpressionExtensions.cs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -218,17 +218,9 @@ private static bool ReturnsMatch(MethodCallExpression expression)
/// TODO: remove this code when https://connect.microsoft.com/VisualStudio/feedback/ViewFeedback.aspx?FeedbackID=331583
/// is fixed.
/// </devdoc>
public static string ToStringFixed(this Expression expression)
public static string ToStringFixed(this Expression expression, bool useFullTypeName = false)
{
return ExpressionStringBuilder.GetString(expression);
}

internal static string ToStringFixed(this Expression expression, bool useFullTypeName)
{
if (useFullTypeName)
return ExpressionStringBuilder.GetString(expression, type => type.FullName);
else
return ExpressionStringBuilder.GetString(expression, type => type.Name);
return ExpressionStringBuilder.GetString(expression, useFullTypeName);
}

/// <summary>
Expand Down
171 changes: 86 additions & 85 deletions Source/ExpressionStringBuilder.cs
View file
Original file line number Diff line number Diff line change
@@ -1,13 +1,14 @@
using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Collections.ObjectModel;
using System.Diagnostics;
using System.Linq;
using System.Linq.Expressions;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Text;
using System.Collections.ObjectModel;

using Moq.Properties;

namespace Moq
Expand All @@ -20,23 +21,18 @@ internal class ExpressionStringBuilder
{
private readonly Expression expression;
private StringBuilder builder;
private Func<Type, string> getTypeName;

internal static string GetString(Expression expression)
{
return GetString(expression, type => type.Name);
}
private bool useFullName;

internal static string GetString(Expression expression, Func<Type, string> getTypeName)
internal static string GetString(Expression expression, bool useFullName = false)
{
var builder = new ExpressionStringBuilder(getTypeName, expression);
var builder = new ExpressionStringBuilder(expression, useFullName);
return builder.ToString();
}

public ExpressionStringBuilder(Func<Type, string> getTypeName, Expression expression)
public ExpressionStringBuilder(Expression expression, bool useFullName)
{
this.getTypeName = getTypeName;
this.expression = expression;
this.useFullName = useFullName;
}

public override string ToString()
Expand Down Expand Up @@ -164,7 +160,7 @@ private void ToStringUnary(UnaryExpression u)
{
case ExpressionType.Convert:
case ExpressionType.ConvertChecked:
builder.Append("(").Append(this.getTypeName(u.Type)).Append(")");
builder.Append('(').Append(this.useFullName ? u.Type.FullName : u.Type.Name).Append(')');
ToString(u.Operand);
return;

Expand All @@ -175,26 +171,26 @@ private void ToStringUnary(UnaryExpression u)

case ExpressionType.Negate:
case ExpressionType.NegateChecked:
builder.Append("-");
builder.Append('-');
ToString(u.Operand);
return;

case ExpressionType.Not:
builder.Append("!(");
ToString(u.Operand);
builder.Append(")");
builder.Append(')');
return;

case ExpressionType.Quote:
ToString(u.Operand);
return;

case ExpressionType.TypeAs:
builder.Append("(");
builder.Append('(');
ToString(u.Operand);
builder.Append(" as ");
builder.Append(u.Type.DisplayName(this.getTypeName));
builder.Append(")");
builder.AppendDisplayName(u.Type, this.useFullName);
builder.Append(')');
return;
}
return;
Expand All @@ -205,31 +201,31 @@ private void ToStringBinary(BinaryExpression b)
if (b.NodeType == ExpressionType.ArrayIndex)
{
ToString(b.Left);
builder.Append("[");
builder.Append('[');
ToString(b.Right);
builder.Append("]");
builder.Append(']');
}
else
{
string @operator = ToStringOperator(b.NodeType);
if (NeedEncloseInParen(b.Left))
{
builder.Append("(");
builder.Append('(');
ToString(b.Left);
builder.Append(")");
builder.Append(')');
}
else
{
ToString(b.Left);
}
builder.Append(" ");
builder.Append(' ');
builder.Append(@operator);
builder.Append(" ");
builder.Append(' ');
if (NeedEncloseInParen(b.Right))
{
builder.Append("(");
builder.Append('(');
ToString(b.Right);
builder.Append(")");
builder.Append(')');
}
else
{
Expand All @@ -256,14 +252,14 @@ private void ToStringConstant(ConstantExpression c)
{
if (value is string)
{
builder.Append("\"").Append(value).Append("\"");
builder.Append('"').Append(value).Append('"');
}
else if (value is IEnumerable enumerable && !(value is IMocked))
{ // ^^^^^^^^^^^^^^^^^^^
// This second check ensures that we have a usable implementation of IEnumerable.
// If value is a mocked object, its IEnumerable implementation might very well
// not work correctly.
builder.Append("[");
builder.Append('[');
bool addComma = false;
const int maxCount = 10;
int count = 0;
Expand All @@ -282,7 +278,7 @@ private void ToStringConstant(ConstantExpression c)
addComma = true;
++count;
}
builder.Append("]");
builder.Append(']');
}
else if (value.ToString() == value.GetType().ToString())
{
Expand All @@ -291,7 +287,7 @@ private void ToStringConstant(ConstantExpression c)
}
else if (c.Type.GetTypeInfo().IsEnum)
{
builder.Append(c.Type.DisplayName(this.getTypeName)).Append(".").Append(value);
builder.AppendDisplayName(c.Type, this.useFullName).Append('.').Append(value);
}
else
{
Expand Down Expand Up @@ -332,9 +328,9 @@ private void ToStringMemberAccess(MemberExpression m)
}
else
{
builder.Append(m.Member.DeclaringType.DisplayName(this.getTypeName));
builder.AppendDisplayName(m.Member.DeclaringType, this.useFullName);
}
builder.Append(".");
builder.Append('.');
builder.Append(m.Member.Name);
return;
}
Expand All @@ -360,56 +356,68 @@ private void ToStringMethodCall(MethodCallExpression node)
}
else // Method is static
{
this.builder.Append(this.getTypeName(node.Method.DeclaringType));
var nodeMethodDeclaringType = node.Method.DeclaringType;
this.builder.Append(this.useFullName ? nodeMethodDeclaringType.FullName : nodeMethodDeclaringType.Name);
}

if (node.Method.IsPropertyIndexerGetter())
{
this.builder.Append("[");
this.builder.Append('[');
AsCommaSeparatedValues(node.Arguments.Skip(paramFrom), ToString);
this.builder.Append("]");
this.builder.Append(']');
}
else if (node.Method.IsPropertyIndexerSetter())
{
this.builder.Append("[");
this.builder.Append('[');
AsCommaSeparatedValues(node.Arguments.Skip(paramFrom), ToString);
this.builder.Append("] = ");
ToString(node.Arguments.Last());
}
else if (node.Method.IsPropertyGetter())
{
this.builder.Append(".").Append(node.Method.Name.Substring(4));
this.builder.Append('.').Append(node.Method.Name.Substring(4));
if (node.Arguments.Count > paramFrom)
{
this.builder.Append("[");
this.builder.Append('[');
AsCommaSeparatedValues(node.Arguments.Skip(paramFrom), ToString);
this.builder.Append("]");
this.builder.Append(']');
}
}
else if (node.Method.IsPropertySetter())
{
this.builder.Append(".").Append(node.Method.Name.Substring(4)).Append(" = ");
this.builder.Append('.').Append(node.Method.Name.Substring(4)).Append(" = ");
ToString(node.Arguments.Last());
}
else if (node.Method.IsGenericMethod)
{
this.builder
.Append(".")
.Append('.')
.Append(node.Method.Name)
.Append("<")
.Append(string.Join(",", node.Method.GetGenericArguments().Select(s => this.getTypeName(s)).ToArray()))
.Append('<');

var nodeMethodGenericArguments = node.Method.GetGenericArguments();
for (int i = 0, n = nodeMethodGenericArguments.Length; i < n; ++i)
{
if (i > 0)
{
this.builder.Append(", ");
}
var name = this.builder.Append(this.useFullName ? nodeMethodGenericArguments[i].FullName : nodeMethodGenericArguments[i].Name);
}

this.builder
.Append(">(");
AsCommaSeparatedValues(node.Arguments.Skip(paramFrom), ToString);
this.builder.Append(")");
this.builder.Append(')');
}
else
{
this.builder
.Append(".")
.Append('.')
.Append(node.Method.Name)
.Append("(");
.Append('(');
AsCommaSeparatedValues(node.Arguments.Skip(paramFrom), ToString);
this.builder.Append(")");
this.builder.Append(')');
}
}
}
Expand Down Expand Up @@ -472,9 +480,9 @@ private void ToStringLambda(LambdaExpression lambda)
}
else
{
builder.Append("(");
builder.Append('(');
AsCommaSeparatedValues(lambda.Parameters, ToStringParameter);
builder.Append(")");
builder.Append(')');
}
builder.Append(" => ");
ToString(lambda.Body);
Expand All @@ -485,10 +493,10 @@ private void ToStringNew(NewExpression nex)
{
Type type = (nex.Constructor == null) ? nex.Type : nex.Constructor.DeclaringType;
builder.Append("new ");
builder.Append(type.DisplayName(this.getTypeName));
builder.Append("(");
builder.AppendDisplayName(type, this.useFullName);
builder.Append('(');
AsCommaSeparatedValues(nex.Arguments, ToString);
builder.Append(")");
builder.Append(')');
return;
}

Expand Down Expand Up @@ -530,10 +538,10 @@ private void ToStringNewArray(NewArrayExpression na)
return;
case ExpressionType.NewArrayBounds:
builder.Append("new ");
builder.Append(na.Type.GetElementType().DisplayName(this.getTypeName));
builder.Append("[");
builder.AppendDisplayName(na.Type.GetElementType(), this.useFullName);
builder.Append('[');
AsCommaSeparatedValues(na.Expressions, ToString);
builder.Append("]");
builder.Append(']');
return;
}
}
Expand Down Expand Up @@ -629,46 +637,39 @@ internal static string ToStringOperator(ExpressionType nodeType)
}
}

internal static class StringExtensions
internal static class StringBuilderExtensions
{
public static string AsCommaSeparatedValues(this IEnumerable<string> source)
public static StringBuilder AppendDisplayName(this StringBuilder builder, Type source, bool useFullName)
{
if (source == null)
Debug.Assert(source != null);

var name = useFullName ? source.FullName : source.Name;
var backtickIndex = name.IndexOf('`');
if (backtickIndex >= 0)
{
return string.Empty;
builder.Append(name, 0, backtickIndex);
}
var result = new StringBuilder(100);
bool appendComma = false;
foreach (var value in source)
else
{
if (appendComma)
{
result.Append(", ");
}
result.Append(value);
appendComma = true;
builder.Append(name);
}
return result.ToString();
}
}

internal static class TypeExtensions
{
public static string DisplayName(this Type source, Func<Type, string> getName)
{
if (source == null)
{
throw new ArgumentNullException("source");
}
var builder = new StringBuilder(100);
builder.Append(getName(source).Split('`').First());
if (source.GetTypeInfo().IsGenericType)
{
builder.Append("<");
builder.Append(source.GetGenericArguments().Select(t => getName(t)).AsCommaSeparatedValues());
builder.Append(">");
var genericArguments = source.GetGenericArguments();
builder.Append('<');
for (int i = 0, n = genericArguments.Length; i < n; ++i)
{
if (i > 0)
{
builder.Append(", ");
}
builder.Append(useFullName ? genericArguments[i].FullName : genericArguments[i].Name);
}
builder.Append('>');
}
return builder.ToString();

return builder;
}
}
}

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