The class model¶

CONTRACT · IMPLEMENTATION · STANDALONE · BORDERLINE CASES

MeshCore's 196 classes fall into three kinds: classes that lay down what another part may expect, classes that implement such an agreement, and classes that stand on their own. This chapter describes that three-way split, states what a contract is and is not, and walks through the 119 classes of the shared tree one by one. The 77 from variants/ appear as a summary at the end.

[!NOTE] Source. This page was verified against the firmware itself: MeshCore v1.16.0, commit 03b6ef4, 28 July 2026 — every class in the tables was checked for file and line number in src/, examples/ and variants/.

What a contract is¶

A contract is a class that exists solely to lay down what another part may expect. It holds no working code, only the list of what an implementation must be able to do, plus sometimes a default answer for when the hardware cannot do something. In C++ you recognise it by its virtual methods, the mandatory ones ending in = 0.

Three properties make something a contract:

It describes, it does not do. Radio does not know how to drive an SX1262; it lays down that there must be something that sends bytes.
The user knows only the contract. Packet handling holds a Radio* and has no idea which chip hangs off it.
Implementations are interchangeable. Every class that implements the contract can replace any other without the user changing.

The logical side of this story — which agreements exist and what they promise — is in Contracts. Here it is about the classes that carry them.

Three columns. On the left fourteen interface classes without code of their
own, in the middle fifty classes that implement one with arrows pointing left,
on the right fifty-five standalone classes without arrows. Along the bottom a
wide bar with the seventy-seven classes from variants runs into the middle
column.

What is not a contract¶

A base class that holds shared code is not a contract but a common parent. ESP32Board is such a case: it implements the board contract and offers code the derived board classes inherit. It therefore sits in group 2, not group 1.

The distinction is not always sharp. BridgeBase and RadioLibWrapper are both an implementation and a parent: they implement AbstractBridge and mesh::Radio respectively, and there are classes hanging under them in turn. Anyone reading the three-way split as a hard partition runs into trouble with those two. They sit in group 2 because they implement a contract; that they also have children of their own changes nothing about that property.

Standalone is everything that is not a contract and implements none either: classes that do one thing and on which nothing depends. ClientACL manages the access list, RegionMap converts region codes, Packet is a data object. They are not replaceable because there is nothing they would have to replace.

An instructive case is CustomSX1262. It sits in group 3, not group 2. The class inherits from RadioLib's SX1262 and implements no MeshCore contract; it is CustomSX1262Wrapper that does, via RadioLibWrapper. That explains why there are two classes per radio chip: one that adapts the chip driver, one that pours the result into the MeshCore contract. See Radio realisation.

The distribution¶

The shared tree counts 119 classes: 14 interface classes, 50 implementation classes and 55 standalone classes.

Group	Count	Characteristic
1 — interface classes	14	Virtual methods only, no working code
2 — implementation classes	50	Inherits from a class in group 1
3 — standalone	55	No contract, implements none either

Group 1 — interface classes (14)¶

Class	Location
`DataStoreHost`	`examples/companion_radio/DataStore.h` r.8
`MillisecondClock`	`src/Dispatcher.h` r.14
`Radio`	`src/Dispatcher.h` r.22
`PacketManager`	`src/Dispatcher.h` r.85
`MeshTables`	`src/Mesh.h` r.16
`MainBoard`	`src/MeshCore.h` r.45
`RTCClock`	`src/MeshCore.h` r.80
`RNG`	`src/Utils.h` r.9
`AbstractBridge`	`src/helpers/AbstractBridge.h` r.5
`BaseSerialInterface`	`src/helpers/BaseSerialInterface.h` r.7
`CommonCLICallbacks`	`src/helpers/CommonCLI.h` r.68
`SensorManager`	`src/helpers/SensorManager.h` r.12
`LocationProvider`	`src/helpers/sensors/LocationProvider.h` r.6
`DisplayDriver`	`src/helpers/ui/DisplayDriver.h` r.6

Two things stand out in this list.

SensorManager and LocationProvider are not in src/ but in src/helpers/. That is not a mistake: they are contracts that only became necessary once sensors arrived, and they have not been moved to the core.

CommonCLICallbacks and DataStoreHost reverse the dependency. They are defined by the layer below but implemented by the application above — MyMesh in examples/simple_repeater/ implements CommonCLICallbacks so that the control code in src/helpers/CommonCLI.cpp can call something without knowing which application is running. The lower layer calls the higher one without knowing it.

Group 2 — implementation classes (50)¶

Class	Contract	Location	Inherits from
`ESP32Board`	Board	`src/helpers/ESP32Board.h` r.18	mesh::MainBoard
`MeshadventurerBoard`	Board	`src/helpers/MeshadventurerBoard.h` r.20	ESP32Board
`NRF52Board`	Board	`src/helpers/NRF52Board.h` r.27	mesh::MainBoard
`NRF52BoardDCDC`	Board	`src/helpers/NRF52Board.h` r.74	NRF52Board
`STM32Board`	Board	`src/helpers/stm32/STM32Board.h` r.6	mesh::MainBoard
`TBeamBoard`	Board	`src/helpers/esp32/TBeamBoard.h` r.91	ESP32Board
`BridgeBase`	Bridge	`src/helpers/bridges/BridgeBase.h` r.21	AbstractBridge
`ESPNowBridge`	Bridge	`src/helpers/bridges/ESPNowBridge.h` r.42	BridgeBase
`RS232Bridge`	Bridge	`src/helpers/bridges/RS232Bridge.h` r.47	BridgeBase
`SimpleMeshTables`	Seen table	`src/helpers/SimpleMeshTables.h` r.11	mesh::MeshTables
`LocalIdentity`	Identity	`src/Identity.h` r.54	Identity
`AutoDiscoverRTCClock`	Clock	`src/helpers/AutoDiscoverRTCClock.h` r.7	mesh::RTCClock
`ESP32RTCClock`	Clock	`src/helpers/ESP32Board.h` r.160	mesh::RTCClock
`VolatileRTCClock`	Clock	`src/helpers/ArduinoHelpers.h` r.6	mesh::RTCClock
`ArduinoSerialInterface`	Interface	`src/helpers/ArduinoSerialInterface.h` r.6	BaseSerialInterface
`SerialBLEInterface`	Interface	`src/helpers/esp32/SerialBLEInterface.h` r.9	BaseSerialInterface, BLESecurityCallbacks, BLEServerCallbacks, BLECharacteristicCallbacks
`SerialBLEInterface`	Interface	`src/helpers/nrf52/SerialBLEInterface.h` r.10	BaseSerialInterface
`SerialWifiInterface`	Interface	`src/helpers/esp32/SerialWifiInterface.h` r.6	BaseSerialInterface
`MicroNMEALocationProvider`	Location	`src/helpers/sensors/MicroNMEALocationProvider.h` r.36	LocationProvider
`RAK12500LocationProvider`	Location	`src/helpers/sensors/EnvironmentSensorManager.cpp` r.177	LocationProvider
`BaseChatMesh`	Mesh	`src/helpers/BaseChatMesh.h` r.59	mesh::Mesh
`MyMesh`	Mesh	`examples/simple_secure_chat/main.cpp` r.73	BaseChatMesh, ContactVisitor
`MyMesh`	Mesh	`examples/simple_repeater/MyMesh.h` r.83	mesh::Mesh, CommonCLICallbacks
`MyMesh`	Mesh	`examples/simple_room_server/MyMesh.h` r.91	mesh::Mesh, CommonCLICallbacks
`MyMesh`	Mesh	`examples/simple_sensor/main.cpp` r.8	SensorMesh
`MyMesh`	Mesh	`examples/companion_radio/MyMesh.h` r.87	BaseChatMesh, DataStoreHost
`SensorMesh`	Mesh	`examples/simple_sensor/SensorMesh.h` r.49	mesh::Mesh, CommonCLICallbacks
`ArduinoMillis`	Millisecond clock	`src/helpers/ArduinoHelpers.h` r.22	mesh::MillisecondClock
`StaticPoolPacketManager`	Packet pool	`src/helpers/StaticPoolPacketManager.h` r.21	mesh::PacketManager
`CustomLLCC68Wrapper`	Radio	`src/helpers/radiolib/CustomLLCC68Wrapper.h` r.7	RadioLibWrapper
`CustomLR1110Wrapper`	Radio	`src/helpers/radiolib/CustomLR1110Wrapper.h` r.7	RadioLibWrapper
`CustomSTM32WLxWrapper`	Radio	`src/helpers/radiolib/CustomSTM32WLxWrapper.h` r.8	RadioLibWrapper
`CustomSX1262Wrapper`	Radio	`src/helpers/radiolib/CustomSX1262Wrapper.h` r.11	RadioLibWrapper
`CustomSX1268Wrapper`	Radio	`src/helpers/radiolib/CustomSX1268Wrapper.h` r.11	RadioLibWrapper
`CustomSX1276Wrapper`	Radio	`src/helpers/radiolib/CustomSX1276Wrapper.h` r.10	RadioLibWrapper
`ESPNOWRadio`	Radio	`src/helpers/esp32/ESPNOWRadio.h` r.5	mesh::Radio
`RadioLibWrapper`	Radio	`src/helpers/radiolib/RadioLibWrappers.h` r.6	mesh::Radio
`E213Display`	Display	`src/helpers/ui/E213Display.h` r.12	DisplayDriver
`E290Display`	Display	`src/helpers/ui/E290Display.h` r.12	DisplayDriver
`GxEPDDisplay`	Display	`src/helpers/ui/GxEPDDisplay.h` r.19	DisplayDriver
`LGFXDisplay`	Display	`src/helpers/ui/LGFXDisplay.h` r.12	DisplayDriver
`NullDisplayDriver`	Display	`src/helpers/ui/NullDisplayDriver.h` r.5	DisplayDriver
`SSD1306Display`	Display	`src/helpers/ui/SSD1306Display.h` r.18	DisplayDriver
`ST7735Display`	Display	`src/helpers/ui/ST7735Display.h` r.10	DisplayDriver
`ST7789Display`	Display	`src/helpers/ui/ST7789Display.h` r.9	DisplayDriver
`ST7789LCDDisplay`	Display	`src/helpers/ui/ST7789LCDDisplay.h` r.10	DisplayDriver
`U8g2Display`	Display	`src/helpers/ui/U8g2Display.h` r.19	DisplayDriver
`EnvironmentSensorManager`	Sensor management	`src/helpers/sensors/EnvironmentSensorManager.h` r.7	SensorManager
`RadioNoiseListener`	Entropy	`src/helpers/radiolib/RadioLibWrappers.h` r.74	mesh::RNG
`StdRNG`	Entropy	`src/helpers/ArduinoHelpers.h` r.27	mesh::RNG

[!NOTE] The Inherits from column gives the base classes as they appear in the declaration, without the access level. One exception is worth mentioning: NRF52BoardDCDC inherits virtual public NRF52Board. That virtual inheritance is needed because thirty board classes in variants/ hang under it and reach NRF52Board along two paths; without virtual each of those boards would get two copies of the base class.

SerialBLEInterface and MyMesh appear more than once. That is not an error in the table: they are different classes with the same name, in different files, and each build compiles exactly one of them. SerialBLEInterface exists twice — one for ESP32, one for nRF52 — and MyMesh five times, one per application that needs one.

Group 3 — standalone (55)¶

Class	Location
`AbstractUITask`	`examples/companion_radio/AbstractUITask.h` r.25
`DataStore`	`examples/companion_radio/DataStore.h` r.16
`SplashScreen`	`examples/companion_radio/ui-new/UITask.cpp` r.34
`HomeScreen`	`examples/companion_radio/ui-new/UITask.cpp` r.86
`MsgPreviewScreen`	`examples/companion_radio/ui-new/UITask.cpp` r.466
`UITask`	`examples/companion_radio/ui-new/UITask.h` r.25
`Button`	`examples/companion_radio/ui-orig/Button.h` r.12
`UITask`	`examples/companion_radio/ui-orig/UITask.h` r.17
`ScrollingStatusBar`	`examples/companion_radio/ui-tiny/ScrollingStatusBar.h` r.18
`SplashScreen`	`examples/companion_radio/ui-tiny/UITask.cpp` r.34
`HomeScreen`	`examples/companion_radio/ui-tiny/UITask.cpp` r.90
`UITask`	`examples/companion_radio/ui-tiny/UITask.h` r.28
`KissModem`	`examples/kiss_modem/KissModem.h` r.100
`RateLimiter`	`examples/simple_repeater/RateLimiter.h` r.5
`UITask`	`examples/simple_repeater/UITask.h` r.6
`UITask`	`examples/simple_room_server/UITask.h` r.6
`TimeSeriesData`	`examples/simple_sensor/TimeSeriesData.h` r.11
`UITask`	`examples/simple_sensor/UITask.h` r.6
`Dispatcher`	`src/Dispatcher.h` r.116
`Identity`	`src/Identity.h` r.11
`GroupChannel`	`src/Mesh.h` r.7
`Mesh`	`src/Mesh.h` r.26
`Packet`	`src/Packet.h` r.42
`Utils`	`src/Utils.h` r.19
`AdvertDataBuilder`	`src/helpers/AdvertDataHelpers.h` r.19
`AdvertDataParser`	`src/helpers/AdvertDataHelpers.h` r.43
`AdvertTimeHelper`	`src/helpers/AdvertDataHelpers.h` r.68
`ContactVisitor`	`src/helpers/BaseChatMesh.h` r.23
`ContactsIterator`	`src/helpers/BaseChatMesh.h` r.30
`ClientACL`	`src/helpers/ClientACL.h` r.40
`CommonCLI`	`src/helpers/CommonCLI.h` r.117
`IdentityStore`	`src/helpers/IdentityStore.h` r.14
`RTC_RX8130CE`	`src/helpers/RTC_RX8130CE.h` r.9
`RefCountedDigitalPin`	`src/helpers/RefCountedDigitalPin.h` r.5
`BufStream`	`src/helpers/RegionMap.cpp` r.7
`RegionMap`	`src/helpers/RegionMap.h` r.23
`PacketQueue`	`src/helpers/StaticPoolPacketManager.h` r.5
`StatsFormatHelper`	`src/helpers/StatsFormatHelper.h` r.5
`TransportKeyStore`	`src/helpers/TransportKeyStore.h` r.16
`StrHelper`	`src/helpers/TxtDataHelpers.h` r.12
`CustomLLCC68`	`src/helpers/radiolib/CustomLLCC68.h` r.8
`CustomLR1110`	`src/helpers/radiolib/CustomLR1110.h` r.6
`CustomSTM32WLx`	`src/helpers/radiolib/CustomSTM32WLx.h` r.8
`CustomSX1262`	`src/helpers/radiolib/CustomSX1262.h` r.8
`CustomSX1268`	`src/helpers/radiolib/CustomSX1268.h` r.8
`CustomSX1276`	`src/helpers/radiolib/CustomSX1276.h` r.11
`LPPReader`	`src/helpers/sensors/LPPDataHelpers.h` r.66
`LPPWriter`	`src/helpers/sensors/LPPDataHelpers.h` r.175
`GenericVibration`	`src/helpers/ui/GenericVibration.h` r.21
`MomentaryButton`	`src/helpers/ui/MomentaryButton.h` r.11
`String`	`src/helpers/ui/OLEDDisplay.h` r.50
`OLEDDisplay`	`src/helpers/ui/OLEDDisplay.h` r.159
`OLEDDisplay`	`src/helpers/ui/OLEDDisplay.h` r.161
`ST7789Spi`	`src/helpers/ui/ST7789Spi.h` r.96
`UIScreen`	`src/helpers/ui/UIScreen.h` r.17

[!NOTE] OLEDDisplay appears twice in src/helpers/ui/OLEDDisplay.h, on lines 159 and 161, behind an #if — one version inherits from Print, the other from Stream. String on line 50 in that same file is a forward reference from vendored code. Neither is MeshCore design but code adopted from ThingPulse; see The source tree.

The 77 from `variants/`¶

variants/ counts 77 class declarations under 73 unique names — four names occur in more than one variant directory. They are not written out one by one, because they all do the same thing: implement a contract with the pin assignment of one board.

Contract being implemented	Classes
Board	65
Sensor management	7
Display	3
Entropy	2

The 65 board classes all implement the same contract in the same way. Four of them are worth naming separately, because they are the only RP2040 board classes: that family is the only one without a shared board class in src/helpers/.

RP2040 board class	Location
`RAK11310Board`	`variants/rak11310/RAK11310Board.h` r.15
`PicoWBoard`	`variants/rpi_picow/PicoWBoard.h` r.11
`WaveshareBoard`	`variants/waveshare_rp2040_lora/WaveshareBoard.h` r.27
`XiaoRP2040Board`	`variants/xiao_rp2040/XiaoRP2040Board.h` r.25

All other board classes inherit from a shared parent — 30 from NRF52BoardDCDC, 23 from ESP32Board, 3 from NRF52Board, 3 from STM32Board, plus a few from HeltecV3Board and TBeamBoard. These four inherit from mesh::MainBoard directly and therefore write out for themselves what the other 61 get from their parent.

Two inheritance trees side by side. On the left the board contract
mesh::MainBoard with ESP32Board, NRF52Board and STM32Board and their
descendants underneath; on the right the four separate RP2040 board classes
hanging directly off the contract, with no intermediate
layer.

Recomputing¶

The counts in this chapter come from tools/design-overview.py:

python3 tools/design-overview.py /path/to/MeshCore --classes

The script counts every line of the form class Name { … or class Name : base { … with the brace on the same line. struct does not count, and neither do forward declarations without a body.

Sources¶

Translated from Dutch by Anthropic Claude