1 /*
2  * Copyright (C) 2020 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.systemui.statusbar.notification.collection.render
18 
19 import android.view.View
20 import java.lang.RuntimeException
21 import java.lang.StringBuilder
22 
23 /**
24  * A controller that represents a single unit of addable/removable view(s) in the notification
25  * shade. Some nodes are just a single view (such as a header), while some might involve many views
26  * (such as a notification row).
27  *
28  * It's possible for nodes to support having child nodes (for example, some notification rows
29  * contain other notification rows). If so, they must implement all of the child-related methods
30  * below.
31  */
32 interface NodeController {
33     /** A string that uniquely(ish) represents the node in the tree. Used for debugging. */
34     val nodeLabel: String
35 
36     val view: View
37 
38     fun getChildAt(index: Int): View? {
39         throw RuntimeException("Not supported")
40     }
41 
42     fun getChildCount(): Int = 0
43 
44     fun addChildAt(child: NodeController, index: Int) {
45         throw RuntimeException("Not supported")
46     }
47 
48     fun moveChildTo(child: NodeController, index: Int) {
49         throw RuntimeException("Not supported")
50     }
51 
52     fun removeChild(child: NodeController, isTransfer: Boolean) {
53         throw RuntimeException("Not supported")
54     }
55 }
56 
57 /**
58  * Used to specify the tree of [NodeController]s that currently make up the shade.
59  */
60 interface NodeSpec {
61     val parent: NodeSpec?
62     val controller: NodeController
63     val children: List<NodeSpec>
64 }
65 
66 class NodeSpecImpl(
67     override val parent: NodeSpec?,
68     override val controller: NodeController
69 ) : NodeSpec {
70     override val children = mutableListOf<NodeSpec>()
71 }
72 
73 /**
74  * Converts a tree spec to human-readable string, for dumping purposes.
75  */
76 fun treeSpecToStr(tree: NodeSpec): String {
77     return StringBuilder().also { treeSpecToStrHelper(tree, it, "") }.toString()
78 }
79 
80 private fun treeSpecToStrHelper(tree: NodeSpec, sb: StringBuilder, indent: String) {
81     sb.append("${indent}{${tree.controller.nodeLabel}}\n")
82     if (tree.children.isNotEmpty()) {
83         val childIndent = "$indent  "
84         for (child in tree.children) {
85             treeSpecToStrHelper(child, sb, childIndent)
86         }
87     }
88 }
89