1 /*
<lambda>null2  * Copyright (C) 2024 The Android Open Source Project
3  *
4  * Licensed under the Apache License, Version 2.0 (the "License");
5  * you may not use this file except in compliance with the License.
6  * You may obtain a copy of the License at
7  *
8  *      http://www.apache.org/licenses/LICENSE-2.0
9  *
10  * Unless required by applicable law or agreed to in writing, software
11  * distributed under the License is distributed on an "AS IS" BASIS,
12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13  * See the License for the specific language governing permissions and
14  * limitations under the License.
15  */
16 
17 package com.android.tools.metalava.model.type
18 
19 import com.android.tools.metalava.model.AnnotationItem
20 import com.android.tools.metalava.model.TypeItem
21 import com.android.tools.metalava.model.TypeModifiers
22 import com.android.tools.metalava.model.TypeNullability
23 
24 /** Modifiers for a [TypeItem]. */
25 class DefaultTypeModifiers(
26     private val annotations: MutableList<AnnotationItem>,
27     private var nullability: TypeNullability,
28     /**
29      * If non-null then this causes this instance to be treated as immutable and any attempt to
30      * mutate it will throw an exception with this as the reason.
31      */
32     private val immutableReason: String? = null,
33 ) : TypeModifiers {
34 
35     private fun ensureMutable() {
36         immutableReason?.let { reason -> error(reason) }
37     }
38 
39     override fun annotations(): List<AnnotationItem> = annotations
40 
41     override fun addAnnotation(annotation: AnnotationItem) {
42         ensureMutable()
43         annotations.add(annotation)
44     }
45 
46     override fun removeAnnotation(annotation: AnnotationItem) {
47         ensureMutable()
48         annotations.remove(annotation)
49     }
50 
51     override fun nullability(): TypeNullability {
52         return nullability
53     }
54 
55     override fun setNullability(newNullability: TypeNullability) {
56         if (newNullability == nullability) return
57         ensureMutable()
58         nullability = newNullability
59     }
60 
61     override fun duplicate(withNullability: TypeNullability?) =
62         DefaultTypeModifiers(annotations.toMutableList(), withNullability ?: nullability)
63 
64     companion object {
65         /** A set of empty, non-null [TypeModifiers] for sharing. */
66         val emptyNonNullModifiers =
67             create(emptyList(), TypeNullability.NONNULL, "emptyNonNullModifiers is shared")
68 
69         /**
70          * Create a [DefaultTypeModifiers].
71          *
72          * If [knownNullability] is `null` then this will compute nullability from the
73          * [annotations], if any, and if not then default to platform nullness.
74          */
75         fun create(
76             annotations: List<AnnotationItem>,
77             knownNullability: TypeNullability? = null,
78             immutableReason: String? = null,
79         ): TypeModifiers {
80             // Use the known nullability, or find if there is a nullness annotation on the type,
81             // defaulting to platform nullness if not.
82             val nullability =
83                 knownNullability
84                     ?: annotations
85                         .firstOrNull { it.isNullnessAnnotation() }
86                         ?.let { TypeNullability.ofAnnotation(it) }
87                         ?: TypeNullability.PLATFORM
88             return DefaultTypeModifiers(annotations.toMutableList(), nullability, immutableReason)
89         }
90     }
91 }
92