1 /*
2  * Copyright 2021 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 androidx.compose.ui.modifier
18 
19 import androidx.compose.runtime.Stable
20 import androidx.compose.ui.Modifier
21 import androidx.compose.ui.internal.JvmDefaultWithCompatibility
22 import androidx.compose.ui.platform.InspectorInfo
23 import androidx.compose.ui.platform.InspectorValueInfo
24 import androidx.compose.ui.platform.debugInspectorInfo
25 
26 /**
27  * A Modifier that can be used to consume [ModifierLocal]s that were provided by other modifiers to
28  * the left of this modifier, or above this modifier in the layout tree.
29  */
30 @Stable
31 @JvmDefaultWithCompatibility
32 interface ModifierLocalConsumer : Modifier.Element {
33     /**
34      * This function is called whenever one of the consumed values has changed. This could be called
35      * in response to the modifier being added, removed or re-ordered.
36      */
onModifierLocalsUpdatednull37     fun onModifierLocalsUpdated(scope: ModifierLocalReadScope)
38 }
39 
40 /**
41  * A Modifier that can be used to consume [ModifierLocal]s that were provided by other modifiers to
42  * the left of this modifier, or above this modifier in the layout tree.
43  */
44 @Stable
45 fun Modifier.modifierLocalConsumer(consumer: ModifierLocalReadScope.() -> Unit): Modifier {
46     return this.then(
47         ModifierLocalConsumerImpl(
48             consumer,
49             debugInspectorInfo {
50                 name = "modifierLocalConsumer"
51                 properties["consumer"] = consumer
52             }
53         )
54     )
55 }
56 
57 @Stable
58 private class ModifierLocalConsumerImpl(
59     val consumer: ModifierLocalReadScope.() -> Unit,
60     debugInspectorInfo: InspectorInfo.() -> Unit
61 ) : ModifierLocalConsumer, InspectorValueInfo(debugInspectorInfo) {
62 
onModifierLocalsUpdatednull63     override fun onModifierLocalsUpdated(scope: ModifierLocalReadScope) {
64         consumer.invoke(scope)
65     }
66 
equalsnull67     override fun equals(other: Any?): Boolean {
68         return other is ModifierLocalConsumerImpl && other.consumer === consumer
69     }
70 
hashCodenull71     override fun hashCode() = consumer.hashCode()
72 }
73