1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
|
/* ****************************************************************************
*
* Copyright (c) Microsoft Corporation.
*
* This source code is subject to terms and conditions of the Microsoft Public License. A
* copy of the license can be found in the License.html file at the root of this distribution. If
* you cannot locate the Microsoft Public License, please send an email to
* dlr@microsoft.com. By using this source code in any fashion, you are agreeing to be bound
* by the terms of the Microsoft Public License.
*
* You must not remove this notice, or any other, from this software.
*
*
* ***************************************************************************/
using System;
using System.Diagnostics;
using System.Dynamic.Utils;
#if SILVERLIGHT
using System.Core;
#endif
#if CLR2
namespace Microsoft.Scripting.Ast {
#else
namespace System.Linq.Expressions {
#endif
/// <summary>
/// Represents a catch statement in a try block.
/// This must have the same return type (i.e., the type of <see cref="P:CatchBlock.Body"/>) as the try block it is associated with.
/// </summary>
#if !SILVERLIGHT
[DebuggerTypeProxy(typeof(Expression.CatchBlockProxy))]
#endif
public sealed class CatchBlock {
private readonly Type _test;
private readonly ParameterExpression _var;
private readonly Expression _body;
private readonly Expression _filter;
internal CatchBlock(Type test, ParameterExpression variable, Expression body, Expression filter) {
_test = test;
_var = variable;
_body = body;
_filter = filter;
}
/// <summary>
/// Gets a reference to the <see cref="Exception"/> object caught by this handler.
/// </summary>
public ParameterExpression Variable {
get { return _var; }
}
/// <summary>
/// Gets the type of <see cref="Exception"/> this handler catches.
/// </summary>
public Type Test {
get { return _test; }
}
/// <summary>
/// Gets the body of the catch block.
/// </summary>
public Expression Body {
get { return _body; }
}
/// <summary>
/// Gets the body of the <see cref="CatchBlock"/>'s filter.
/// </summary>
public Expression Filter {
get {
return _filter;
}
}
/// <summary>
/// Returns a <see cref="String"/> that represents the current <see cref="Object"/>.
/// </summary>
/// <returns>A <see cref="String"/> that represents the current <see cref="Object"/>. </returns>
public override string ToString() {
return ExpressionStringBuilder.CatchBlockToString(this);
}
/// <summary>
/// Creates a new expression that is like this one, but using the
/// supplied children. If all of the children are the same, it will
/// return this expression.
/// </summary>
/// <param name="variable">The <see cref="Variable" /> property of the result.</param>
/// <param name="filter">The <see cref="Filter" /> property of the result.</param>
/// <param name="body">The <see cref="Body" /> property of the result.</param>
/// <returns>This expression if no children changed, or an expression with the updated children.</returns>
public CatchBlock Update(ParameterExpression variable, Expression filter, Expression body) {
if (variable == Variable && filter == Filter && body == Body) {
return this;
}
return Expression.MakeCatchBlock(Test, variable, body, filter);
}
}
public partial class Expression {
/// <summary>
/// Creates a <see cref="CatchBlock"/> representing a catch statement.
/// The <see cref="Type"/> of object to be caught can be specified but no reference to the object
/// will be available for use in the <see cref="CatchBlock"/>.
/// </summary>
/// <param name="type">The <see cref="Type"/> of <see cref="Exception"/> this <see cref="CatchBlock"/> will handle.</param>
/// <param name="body">The body of the catch statement.</param>
/// <returns>The created <see cref="CatchBlock"/>.</returns>
public static CatchBlock Catch(Type type, Expression body) {
return MakeCatchBlock(type, null, body, null);
}
/// <summary>
/// Creates a <see cref="CatchBlock"/> representing a catch statement with a reference to the caught object for use in the handler body.
/// </summary>
/// <param name="variable">A <see cref="ParameterExpression"/> representing a reference to the <see cref="Exception"/> object caught by this handler.</param>
/// <param name="body">The body of the catch statement.</param>
/// <returns>The created <see cref="CatchBlock"/>.</returns>
public static CatchBlock Catch(ParameterExpression variable, Expression body) {
ContractUtils.RequiresNotNull(variable, "variable");
return MakeCatchBlock(variable.Type, variable, body, null);
}
/// <summary>
/// Creates a <see cref="CatchBlock"/> representing a catch statement with
/// an <see cref="Exception"/> filter but no reference to the caught <see cref="Exception"/> object.
/// </summary>
/// <param name="type">The <see cref="Type"/> of <see cref="Exception"/> this <see cref="CatchBlock"/> will handle.</param>
/// <param name="body">The body of the catch statement.</param>
/// <param name="filter">The body of the <see cref="Exception"/> filter.</param>
/// <returns>The created <see cref="CatchBlock"/>.</returns>
public static CatchBlock Catch(Type type, Expression body, Expression filter) {
return MakeCatchBlock(type, null, body, filter);
}
/// <summary>
/// Creates a <see cref="CatchBlock"/> representing a catch statement with
/// an <see cref="Exception"/> filter and a reference to the caught <see cref="Exception"/> object.
/// </summary>
/// <param name="variable">A <see cref="ParameterExpression"/> representing a reference to the <see cref="Exception"/> object caught by this handler.</param>
/// <param name="body">The body of the catch statement.</param>
/// <param name="filter">The body of the <see cref="Exception"/> filter.</param>
/// <returns>The created <see cref="CatchBlock"/>.</returns>
public static CatchBlock Catch(ParameterExpression variable, Expression body, Expression filter) {
ContractUtils.RequiresNotNull(variable, "variable");
return MakeCatchBlock(variable.Type, variable, body, filter);
}
/// <summary>
/// Creates a <see cref="CatchBlock"/> representing a catch statement with the specified elements.
/// </summary>
/// <param name="type">The <see cref="Type"/> of <see cref="Exception"/> this <see cref="CatchBlock"/> will handle.</param>
/// <param name="variable">A <see cref="ParameterExpression"/> representing a reference to the <see cref="Exception"/> object caught by this handler.</param>
/// <param name="body">The body of the catch statement.</param>
/// <param name="filter">The body of the <see cref="Exception"/> filter.</param>
/// <returns>The created <see cref="CatchBlock"/>.</returns>
/// <remarks><paramref name="type"/> must be non-null and match the type of <paramref name="variable"/> (if it is supplied).</remarks>
public static CatchBlock MakeCatchBlock(Type type, ParameterExpression variable, Expression body, Expression filter) {
ContractUtils.RequiresNotNull(type, "type");
ContractUtils.Requires(variable == null || TypeUtils.AreEquivalent(variable.Type, type), "variable");
if (variable != null && variable.IsByRef) {
throw Error.VariableMustNotBeByRef(variable, variable.Type);
}
RequiresCanRead(body, "body");
if (filter != null) {
RequiresCanRead(filter, "filter");
if (filter.Type != typeof(bool)) throw Error.ArgumentMustBeBoolean();
}
return new CatchBlock(type, variable, body, filter);
}
}
}
|