1 /*
2 * Copyright (c) 2018, 2019, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation. Oracle designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Oracle in the LICENSE file that accompanied this code.
10 *
11 * This code is distributed in the hope that it will be useful, but WITHOUT
12 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 * version 2 for more details (a copy is included in the LICENSE file that
15 * accompanied this code).
16 *
17 * You should have received a copy of the GNU General Public License version
18 * 2 along with this work; if not, write to the Free Software Foundation,
19 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
20 *
21 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
22 * or visit www.oracle.com if you need additional information or have any
23 * questions.
24 */
25 package java.lang.constant;
26
27 import java.lang.invoke.MethodHandles;
28 import java.lang.invoke.MethodType;
29 import java.security.AccessController;
30 import java.security.PrivilegedAction;
31 import java.util.Arrays;
32 import java.util.List;
33
34 import static java.util.Objects.requireNonNull;
35
36 /**
37 * A <a href="package-summary.html#nominal">nominal descriptor</a> for a
38 * {@link MethodType}. A {@linkplain MethodTypeDescImpl} corresponds to a
39 * {@code Constant_MethodType_info} entry in the constant pool of a classfile.
40 */
41 final class MethodTypeDescImpl implements MethodTypeDesc {
42 private final ClassDesc returnType;
43 private final ClassDesc[] argTypes;
44
45 /**
46 * Constructs a {@linkplain MethodTypeDesc} with the specified return type
47 * and parameter types
48 *
49 * @param returnType a {@link ClassDesc} describing the return type
50 * @param argTypes {@link ClassDesc}s describing the parameter types
51 */
52 MethodTypeDescImpl(ClassDesc returnType, ClassDesc[] argTypes) {
53 this.returnType = requireNonNull(returnType);
54 this.argTypes = requireNonNull(argTypes);
55
56 for (ClassDesc cr : argTypes)
57 if (cr.isPrimitive() && cr.descriptorString().equals("V"))
58 throw new IllegalArgumentException("Void parameters not permitted");
59 }
60
61 /**
62 * Creates a {@linkplain MethodTypeDescImpl} given a method descriptor string.
63 *
64 * @param descriptor the method descriptor string
65 * @return a {@linkplain MethodTypeDescImpl} describing the desired method type
66 * @throws IllegalArgumentException if the descriptor string is not a valid
67 * method descriptor
68 * @jvms 4.3.3 Method Descriptors
69 */
70 static MethodTypeDescImpl ofDescriptor(String descriptor) {
71 requireNonNull(descriptor);
72 List<String> types = ConstantUtils.parseMethodDescriptor(descriptor);
73 ClassDesc[] paramTypes = types.stream().skip(1).map(ClassDesc::ofDescriptor).toArray(ClassDesc[]::new);
74 return new MethodTypeDescImpl(ClassDesc.ofDescriptor(types.get(0)), paramTypes);
75 }
76
77 @Override
78 public ClassDesc returnType() {
79 return returnType;
80 }
81
82 @Override
83 public int parameterCount() {
84 return argTypes.length;
85 }
86
87 @Override
88 public ClassDesc parameterType(int index) {
89 return argTypes[index];
90 }
91
92 @Override
93 public List<ClassDesc> parameterList() {
94 return List.of(argTypes);
95 }
96
97 @Override
98 public ClassDesc[] parameterArray() {
99 return argTypes.clone();
100 }
101
102 @Override
103 public MethodTypeDesc changeReturnType(ClassDesc returnType) {
104 return MethodTypeDesc.of(returnType, argTypes);
105 }
106
107 @Override
108 public MethodTypeDesc changeParameterType(int index, ClassDesc paramType) {
109 ClassDesc[] newArgs = argTypes.clone();
110 newArgs[index] = paramType;
111 return MethodTypeDesc.of(returnType, newArgs);
112 }
113
114 @Override
115 public MethodTypeDesc dropParameterTypes(int start, int end) {
116 if (start < 0 || start >= argTypes.length || end < 0 || end > argTypes.length || start > end)
117 throw new IndexOutOfBoundsException();
118 ClassDesc[] newArgs = new ClassDesc[argTypes.length - (end - start)];
119 System.arraycopy(argTypes, 0, newArgs, 0, start);
120 System.arraycopy(argTypes, end, newArgs, start, argTypes.length - end);
121 return MethodTypeDesc.of(returnType, newArgs);
122 }
123
124 @Override
125 public MethodTypeDesc insertParameterTypes(int pos, ClassDesc... paramTypes) {
126 if (pos < 0 || pos > argTypes.length)
127 throw new IndexOutOfBoundsException(pos);
128 ClassDesc[] newArgs = new ClassDesc[argTypes.length + paramTypes.length];
129 System.arraycopy(argTypes, 0, newArgs, 0, pos);
130 System.arraycopy(paramTypes, 0, newArgs, pos, paramTypes.length);
131 System.arraycopy(argTypes, pos, newArgs, pos+paramTypes.length, argTypes.length - pos);
132 return MethodTypeDesc.of(returnType, newArgs);
133 }
134
135 @Override
136 public MethodType resolveConstantDesc(MethodHandles.Lookup lookup) throws ReflectiveOperationException {
137 MethodType mtype = AccessController.doPrivileged(new PrivilegedAction<>() {
138 @Override
139 public MethodType run() {
140 return MethodType.fromMethodDescriptorString(descriptorString(),
141 lookup.lookupClass().getClassLoader());
142 }
143 });
144
145 // let's check that the lookup has access to all the types in the method type
146 lookup.accessClass(mtype.returnType());
147 for (Class<?> paramType: mtype.parameterArray()) {
148 lookup.accessClass(paramType);
149 }
150 return mtype;
151 }
152
153 /**
154 * Returns {@code true} if this {@linkplain MethodTypeDescImpl} is
155 * equal to another {@linkplain MethodTypeDescImpl}. Equality is
156 * determined by the two descriptors having equal return types and argument
157 * types.
158 *
159 * @param o the {@code MethodTypeDescImpl} to compare to this
160 * {@code MethodTypeDescImpl}
161 * @return {@code true} if the specified {@code MethodTypeDescImpl} is
162 * equals to this {@code MethodTypeDescImpl}.
163 */
164 @Override
165 public boolean equals(Object o) {
166 if (this == o) return true;
167 if (o == null || getClass() != o.getClass()) return false;
168
169 MethodTypeDescImpl constant = (MethodTypeDescImpl) o;
170
171 return returnType.equals(constant.returnType)
172 && Arrays.equals(argTypes, constant.argTypes);
173 }
174
175 @Override
176 public int hashCode() {
177 int result = returnType.hashCode();
178 result = 31 * result + Arrays.hashCode(argTypes);
179 return result;
180 }
181
182 @Override
183 public String toString() {
184 return String.format("MethodTypeDesc[%s]", displayDescriptor());
185 }
186 }