summaryrefslogtreecommitdiff
path: root/src/SMAPI/Framework/ModLoading/Framework/RewriteHelper.cs
blob: 4b88148fdee10f284b7483d599fd45d8fa3536c6 (plain)
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
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
using System;
using System.Linq;
using System.Reflection;
using Mono.Cecil;
using Mono.Cecil.Cil;

namespace StardewModdingAPI.Framework.ModLoading.Framework
{
    /// <summary>Provides helper methods for field rewriters.</summary>
    internal static class RewriteHelper
    {
        /*********
        ** Fields
        *********/
        /// <summary>The comparer which heuristically compares type definitions.</summary>
        private static readonly TypeReferenceComparer TypeDefinitionComparer = new TypeReferenceComparer();


        /*********
        ** Public methods
        *********/
        /// <summary>Get the field reference from an instruction if it matches.</summary>
        /// <param name="instruction">The IL instruction.</param>
        public static FieldReference AsFieldReference(Instruction instruction)
        {
            return instruction.OpCode == OpCodes.Ldfld || instruction.OpCode == OpCodes.Ldsfld || instruction.OpCode == OpCodes.Stfld || instruction.OpCode == OpCodes.Stsfld
                ? (FieldReference)instruction.Operand
                : null;
        }

        /// <summary>Get whether the field is a reference to the expected type and field.</summary>
        /// <param name="instruction">The IL instruction.</param>
        /// <param name="fullTypeName">The full type name containing the expected field.</param>
        /// <param name="fieldName">The name of the expected field.</param>
        public static bool IsFieldReferenceTo(Instruction instruction, string fullTypeName, string fieldName)
        {
            FieldReference fieldRef = RewriteHelper.AsFieldReference(instruction);
            return RewriteHelper.IsFieldReferenceTo(fieldRef, fullTypeName, fieldName);
        }

        /// <summary>Get whether the field is a reference to the expected type and field.</summary>
        /// <param name="fieldRef">The field reference to check.</param>
        /// <param name="fullTypeName">The full type name containing the expected field.</param>
        /// <param name="fieldName">The name of the expected field.</param>
        public static bool IsFieldReferenceTo(FieldReference fieldRef, string fullTypeName, string fieldName)
        {
            return
                fieldRef != null
                && fieldRef.DeclaringType.FullName == fullTypeName
                && fieldRef.Name == fieldName;
        }

        /// <summary>Get the method reference from an instruction if it matches.</summary>
        /// <param name="instruction">The IL instruction.</param>
        public static MethodReference AsMethodReference(Instruction instruction)
        {
            return instruction.OpCode == OpCodes.Call || instruction.OpCode == OpCodes.Callvirt || instruction.OpCode == OpCodes.Newobj
                ? (MethodReference)instruction.Operand
                : null;
        }

        /// <summary>Get the CIL instruction to load a value onto the stack.</summary>
        /// <param name="rawValue">The constant value to inject.</param>
        /// <returns>Returns the instruction, or <c>null</c> if the value type isn't supported.</returns>
        public static Instruction GetLoadValueInstruction(object rawValue)
        {
            return rawValue switch
            {
                null => Instruction.Create(OpCodes.Ldnull),
                bool value => Instruction.Create(value ? OpCodes.Ldc_I4_1 : OpCodes.Ldc_I4_0),
                int value => Instruction.Create(OpCodes.Ldc_I4, value), // int32
                long value => Instruction.Create(OpCodes.Ldc_I8, value), // int64
                float value => Instruction.Create(OpCodes.Ldc_R4, value), // float32
                double value => Instruction.Create(OpCodes.Ldc_R8, value), // float64
                string value => Instruction.Create(OpCodes.Ldstr, value),
                _ => null
            };
        }

        /// <summary>Get whether a type matches a type reference.</summary>
        /// <param name="type">The defined type.</param>
        /// <param name="reference">The type reference.</param>
        public static bool IsSameType(Type type, TypeReference reference)
        {
            // 
            // duplicated by IsSameType(TypeReference, TypeReference) below
            //

            // same namespace & name
            if (type.Namespace != reference.Namespace || type.Name != reference.Name)
                return false;

            // same generic parameters
            if (type.IsGenericType)
            {
                if (!reference.IsGenericInstance)
                    return false;

                Type[] defGenerics = type.GetGenericArguments();
                TypeReference[] refGenerics = ((GenericInstanceType)reference).GenericArguments.ToArray();
                if (defGenerics.Length != refGenerics.Length)
                    return false;
                for (int i = 0; i < defGenerics.Length; i++)
                {
                    if (!RewriteHelper.IsSameType(defGenerics[i], refGenerics[i]))
                        return false;
                }
            }

            return true;
        }

        /// <summary>Get whether a type matches a type reference.</summary>
        /// <param name="type">The defined type.</param>
        /// <param name="reference">The type reference.</param>
        public static bool IsSameType(TypeReference type, TypeReference reference)
        {
            // 
            // duplicated by IsSameType(Type, TypeReference) above
            //

            // same namespace & name
            if (type.Namespace != reference.Namespace || type.Name != reference.Name)
                return false;

            // same generic parameters
            if (type.IsGenericInstance)
            {
                if (!reference.IsGenericInstance)
                    return false;

                TypeReference[] defGenerics = ((GenericInstanceType)type).GenericArguments.ToArray();
                TypeReference[] refGenerics = ((GenericInstanceType)reference).GenericArguments.ToArray();
                if (defGenerics.Length != refGenerics.Length)
                    return false;
                for (int i = 0; i < defGenerics.Length; i++)
                {
                    if (!RewriteHelper.IsSameType(defGenerics[i], refGenerics[i]))
                        return false;
                }
            }

            return true;
        }

        /// <summary>Determine whether two type IDs look like the same type, accounting for placeholder values such as !0.</summary>
        /// <param name="typeA">The type ID to compare.</param>
        /// <param name="typeB">The other type ID to compare.</param>
        /// <returns>true if the type IDs look like the same type, false if not.</returns>
        public static bool LooksLikeSameType(TypeReference typeA, TypeReference typeB)
        {
            return RewriteHelper.TypeDefinitionComparer.Equals(typeA, typeB);
        }

        /// <summary>Get whether a method definition matches the signature expected by a method reference.</summary>
        /// <param name="definition">The method definition.</param>
        /// <param name="reference">The method reference.</param>
        public static bool HasMatchingSignature(MethodBase definition, MethodReference reference)
        {
            // 
            // duplicated by HasMatchingSignature(MethodDefinition, MethodReference) below
            //

            // same name
            if (definition.Name != reference.Name)
                return false;

            // same arguments
            ParameterInfo[] definitionParameters = definition.GetParameters();
            ParameterDefinition[] referenceParameters = reference.Parameters.ToArray();
            if (referenceParameters.Length != definitionParameters.Length)
                return false;
            for (int i = 0; i < referenceParameters.Length; i++)
            {
                if (!RewriteHelper.IsSameType(definitionParameters[i].ParameterType, referenceParameters[i].ParameterType))
                    return false;
            }
            return true;
        }

        /// <summary>Get whether a method definition matches the signature expected by a method reference.</summary>
        /// <param name="definition">The method definition.</param>
        /// <param name="reference">The method reference.</param>
        public static bool HasMatchingSignature(MethodDefinition definition, MethodReference reference)
        {
            // 
            // duplicated by HasMatchingSignature(MethodBase, MethodReference) above
            //

            // same name
            if (definition.Name != reference.Name)
                return false;

            // same arguments
            ParameterDefinition[] definitionParameters = definition.Parameters.ToArray();
            ParameterDefinition[] referenceParameters = reference.Parameters.ToArray();
            if (referenceParameters.Length != definitionParameters.Length)
                return false;
            for (int i = 0; i < referenceParameters.Length; i++)
            {
                if (!RewriteHelper.IsSameType(definitionParameters[i].ParameterType, referenceParameters[i].ParameterType))
                    return false;
            }
            return true;
        }

        /// <summary>Get whether a type has a method whose signature matches the one expected by a method reference.</summary>
        /// <param name="type">The type to check.</param>
        /// <param name="reference">The method reference.</param>
        public static bool HasMatchingSignature(Type type, MethodReference reference)
        {
            if (reference.Name == ".ctor")
            {
                return type
                    .GetConstructors(BindingFlags.Instance | BindingFlags.Static | BindingFlags.DeclaredOnly | BindingFlags.Public)
                    .Any(method => RewriteHelper.HasMatchingSignature(method, reference));
            }

            return type
                .GetMethods(BindingFlags.Instance | BindingFlags.Static | BindingFlags.DeclaredOnly | BindingFlags.Public)
                .Any(method => RewriteHelper.HasMatchingSignature(method, reference));
        }
    }
}