go-waku/library/signals.go

79 lines
1.9 KiB
Go

package main
/*
#include <stdbool.h>
#include <stdlib.h>
extern bool StatusServiceSignalEvent(const char *jsonEvent);
extern void SetEventCallback(void *cb);
*/
import "C"
import (
"encoding/json"
"fmt"
"unsafe"
)
// SignalHandler defines a minimal interface
// a signal handler needs to implement.
//nolint
type SignalHandler interface {
HandleSignal(string)
}
// SignalHandler is a simple callback function that gets called when any signal is received
type MobileSignalHandler func([]byte)
// storing the current mobile signal handler here
var mobileSignalHandler MobileSignalHandler
// SignalEnvelope is a general signal sent upward from node to app
type SignalEnvelope struct {
NodeID int `json:"nodeId"`
Type string `json:"type"`
Event interface{} `json:"event"`
}
// NewEnvelope creates new envlope of given type and event payload.
func NewEnvelope(nodeId int, typ string, event interface{}) *SignalEnvelope {
return &SignalEnvelope{
NodeID: nodeId,
Type: typ,
Event: event,
}
}
// send sends application signal (in JSON) upwards to application (via default notification handler)
func send(node int, typ string, event interface{}) {
signal := NewEnvelope(node, typ, event)
data, err := json.Marshal(&signal)
if err != nil {
fmt.Println("marshal signal error", err)
return
}
// If a Go implementation of signal handler is set, let's use it.
if mobileSignalHandler != nil {
mobileSignalHandler(data)
} else {
// ...and fallback to C implementation otherwise.
str := C.CString(string(data))
C.StatusServiceSignalEvent(str)
C.free(unsafe.Pointer(str))
}
}
// SetMobileSignalHandler setup geth callback to notify about new signal
// used for gomobile builds
//nolint
func SetMobileSignalHandler(handler SignalHandler) {
mobileSignalHandler = func(data []byte) {
if len(data) > 0 {
handler.HandleSignal(string(data))
}
}
}
func setEventCallback(cb unsafe.Pointer) {
C.SetEventCallback(cb)
}