1 // Copyright 2023 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 15 #pragma once 16 #include <pw_assert/check.h> 17 18 #include <cstddef> 19 #include <queue> 20 21 #include "pw_bluetooth_sapphire/internal/host/common/inspect.h" 22 23 namespace bt { 24 25 // This class is intended to represent a list node in Inspect, which doesn't 26 // support lists natively. Furthermore, it makes sure that the number of list 27 // items doesn't exceed |capacity|. 28 // 29 // Each item in BoundedInspectListNode is represented as a child node with name 30 // as index. This index is always increasing and does not wrap around. For 31 // example, if capacity is 3, then the children names are `[0, 1, 2]` on the 32 // first three additions. When a new node is added, `0` is popped, and the 33 // children names are `[1, 2, 3]`. 34 // 35 // Example Usage: 36 // BoundedInspectListNode list(/*capacity=*/2); 37 // list.AttachInspect(parent_node); 38 // 39 // auto& item_0 = list.CreateItem(); 40 // item_0.node.RecordInt("property_0", 0); 41 // 42 // auto& item_1 = list.CreateItem(); 43 // item_1.node.RecordInt("property_A", 1); 44 // item_1.node.RecordInt("property_B", 2); 45 // 46 // Inspect Tree: 47 // example_list: 48 // 0: 49 // property_0: 0 50 // 1: 51 // property_A: 1 52 // property_B: 2 53 class BoundedInspectListNode { 54 public: 55 struct Item { 56 // The list child node with the index as it's name (0, 1, 2...). 57 inspect::Node node; 58 }; 59 BoundedInspectListNode(size_t capacity)60 explicit BoundedInspectListNode(size_t capacity) : capacity_(capacity) { 61 PW_CHECK(capacity_ > 0u); 62 } 63 ~BoundedInspectListNode() = default; 64 65 // Attach this node as a child of |parent| with the name |name|. 66 void AttachInspect(inspect::Node& parent, std::string name); 67 68 // Add an item to the list, removing a previous item if the list is at 69 // capacity. The returned item reference is valid until the next item is added 70 // (or this list node is destroyed). 71 Item& CreateItem(); 72 73 private: 74 inspect::Node list_node_; 75 size_t next_index_ = 0; 76 const size_t capacity_; 77 std::queue<Item> items_; 78 }; 79 80 } // namespace bt 81