Skip to main content

GSM module

This document details the implementation of the GSM module within the PaxOS operating system. The module handles communication with a GSM/GPRS modem, enabling functionalities like sending/receiving SMS messages, making/receiving calls, and managing MMS.

1. contacts.cpp / contacts.hpp​

This module manages contact information. Contacts are stored in a JSON file (/apps/contacts/list.json) and loaded into memory for quick access.

Data Structures​

  • Contacts::contact: Represents a single contact with name (std::string) and phone (std::string) fields.

Functions​

  • Contacts::load(): Loads contacts from the list.json file into the contactList vector. Handles JSON parsing errors.
  • Contacts::save(): Saves the contactList to the list.json file in JSON format.
  • Contacts::listContacts(): Returns a copy of the contactList.
  • Contacts::addContact(contact c): Adds a new contact to the contactList.
  • Contacts::deleteContact(std::string name): Deletes a contact with the given name from the contactList.
  • Contacts::editContact(std::string name, contact c): Edits the contact with the given name, updating its information with the provided contact object.
  • Contacts::getContact(std::string name): Returns the contact object associated with the given name. Returns an empty contact if not found.
  • Contacts::getByNumber(std::string number): Returns the contact object associated with the given phone number. Returns an empty contact if not found.

2. conversation.cpp / conversation.hpp​

This module handles conversation data, including loading and saving messages for each conversation.

Data Structures​

  • Conversations::Message: Represents a single message with message (std::string), who (bool indicating sender - false for self, true for other), and date (std::string) fields.
  • Conversations::Conversation: Represents a conversation with a specific number (std::string) and a vector of messages (std::vector<Message>).

Functions​

  • Conversations::loadConversation(const storage::Path &filePath, Conversation &conv): Loads a conversation from the specified JSON file. Handles file errors and JSON parsing exceptions.
  • Conversations::saveConversation(const storage::Path &filePath, const Conversation &conv): Saves a conversation to the specified JSON file. Limits the number of saved messages to MAX_MESSAGES (40), keeping the most recent ones. Creates the necessary directories if they don't exist.

3. gsm.cpp / gsm.hpp​

This module provides the core GSM functionality, interacting directly with the GSM modem. It manages calls, SMS, MMS, network status, and battery level.

Constants​

  • BAUDRATE: Default baud rate for serial communication (921600).
  • MESSAGES_LOCATION: Directory for storing message data (apps/messages/data).
  • MESSAGES_IMAGES_LOCATION: Directory for storing MMS images (apps/messages/images).
  • MESSAGES_NOTIF_LOCATION: File storing unread message notifications (apps/messages/unread.txt).
  • MAX_MESSAGES: Maximum number of messages stored per conversation (40).

Data Structures​

  • GSM::Request: Represents a request to be executed by the GSM module, with a function (std::function<void(void)>) and a priority (enum).
  • GSM::Key: Represents a key string to watch for in the GSM modem's responses, with a key (std::string) and a function (std::function<void()>) to execute when the key is found.
  • GSM::State: Represents the current state of the GSM module (call state, call failure, calling number).
  • GSM::Message: Represents an SMS message, with number, message, and date.
  • GSM::ExternalEvents: Namespace containing callback functions for incoming calls, new messages, and message errors.
  • GSM::Stream::Chunk: Used for streaming MMS data; contains a data pointer and size. (ESP_PLATFORM only)

Functions​

  • GSM::init(): Initializes the GSM modem, including setting baud rate and handling modem power-on (ESP_PLATFORM specific).
  • GSM::reInit(): Re-initializes the serial communication after clock speed changes.
  • GSM::download(uint64_t timeout = 50): Reads data from the GSM modem's serial port with a timeout.
  • GSM::send(const std::string &message, const std::string &answerKey, uint64_t timeout = 200): Sends a command to the GSM modem and waits for a specific response key. Returns the modem's full response.
  • GSM::appendRequest(Request request): Adds a request to the queue of requests to be processed by the GSM module.
  • GSM::process(): Processes received data, checking for key strings and executing associated functions.
  • GSM::checkRequest(): Executes pending requests in the queue, prioritizing high-priority requests.
  • GSM::onRinging(): Handles incoming call events, updating the module's state.
  • GSM::onHangOff(): Handles call hang-up events.
  • GSM::onMessage(): Handles incoming SMS/MMS messages. Decodes PDUs, saves messages to conversations, and triggers the onNewMessage callback.
  • GSM::sendMessage(const std::string &number, const std::string &message): Sends an SMS message. Saves the sent message to the conversation history.
  • GSM::newMessage(std::string number, std::string message): Queues a message to be sent.
  • GSM::sendCall(const std::string &number): Initiates a call to the specified number.
  • GSM::newCall(std::string number): Queues a call to be made.
  • GSM::endCall(): Ends the current call.
  • GSM::acceptCall(): Accepts an incoming call.
  • GSM::rejectCall(): Rejects an incoming call.
  • GSM::getVoltage(): Retrieves the battery voltage.
  • GSM::getBatteryLevel(): Calculates and returns the battery level (0.0 - 1.0) based on voltage.
  • GSM::updateHour(): Updates the current time from the GSM modem.
  • GSM::getHour(): Queues a request to update the time.
  • GSM::getNetworkStatus(): Returns the network signal quality.
  • GSM::updateNetworkQuality(): Updates the network signal quality.
  • GSM::getNetworkQuality(): Queues a request to update the network quality.
  • GSM::isFlightMode(): Checks if flight mode is enabled.
  • GSM::setFlightMode(bool mode): Sets the flight mode.
  • GSM::run(): Main loop of the GSM module. Handles initialization, request processing, and event handling.
  • GSM::getHttpMMS(std::string number, std::string url): Downloads and processes MMS messages (ESP_PLATFORM only).

4. message.cpp / message.hpp​

Provides functions for loading and saving messages from/to JSON files. This module seems redundant given the similar functionality in conversation.cpp/hpp, and its usage isn't clear within the provided code.

Data Structures​

  • Message::Message: Same structure as Conversations::Message.

Functions​

  • Message::loadMessages(const std::string& filePath, std::vector<Message>& messages): Loads messages from a JSON file.
  • Message::saveMessages(const std::string& filePath, const std::vector<Message>& messages): Saves messages to a JSON file.

5. pdu.cpp / pdu.hpp​

This module handles the decoding of PDU-formatted messages received from the GSM modem.

Data Structures​

  • PDU: Contains the decoded information from a PDU string: sender (std::string), message (std::string), url (std::string for MMS URLs), and type (enum PDU_type: SMS, MMS, UNKNOWN).

Functions​

  • decodePDU(std::string pdu): Decodes a PDU string and returns a PDU object containing the extracted information (sender, message, URL, type).