Add API for setting loglevel & loghandler (#20)

Author: Gijs Peskens

go.mod

@@ -2,4 +2,7 @@ module github.com/haivision/srtgo
 
 go 1.12
 
-require golang.org/x/sys v0.0.0-20200926100807-9d91bd62050c
+require (
+	github.com/mattn/go-pointer v0.0.1
+	golang.org/x/sys v0.0.0-20200926100807-9d91bd62050c
+)

go.sum

@@ -1,2 +1,4 @@
+github.com/mattn/go-pointer v0.0.1 h1:n+XhsuGeVO6MEAp7xyEukFINEa+Quek5psIR/ylA6o0=
+github.com/mattn/go-pointer v0.0.1/go.mod h1:2zXcozF6qYGgmsG+SeTZz3oAbFLdD3OWqnUbNvJZAlc=
 golang.org/x/sys v0.0.0-20200926100807-9d91bd62050c h1:38q6VNPWR010vN82/SB121GujZNIfAUb4YttE2rhGuc=
 golang.org/x/sys v0.0.0-20200926100807-9d91bd62050c/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=

logging.go

@@ -0,0 +1,67 @@
+package srtgo
+
+/*
+#cgo LDFLAGS: -lsrt
+#include <srt/srt.h>
+extern void srtLogCB(void* opaque, int level, const char* file, int line, const char* area, const char* message);
+*/
+import "C"
+
+import (
+	"sync"
+	"unsafe"
+
+	gopointer "github.com/mattn/go-pointer"
+)
+
+type LogCallBackFunc func(level SrtLogLevel, file string, line int, area, message string)
+
+type SrtLogLevel int
+
+const (
+	//	SrtLogLevelEmerg = int(C.LOG_EMERG)
+	//	SrtLogLevelAlert = int(C.LOG_ALERT)
+	SrtLogLevelCrit    SrtLogLevel = SrtLogLevel(C.LOG_CRIT)
+	SrtLogLevelErr     SrtLogLevel = SrtLogLevel(C.LOG_ERR)
+	SrtLogLevelWarning SrtLogLevel = SrtLogLevel(C.LOG_WARNING)
+	SrtLogLevelNotice  SrtLogLevel = SrtLogLevel(C.LOG_NOTICE)
+	SrtLogLevelInfo    SrtLogLevel = SrtLogLevel(C.LOG_INFO)
+	SrtLogLevelDebug   SrtLogLevel = SrtLogLevel(C.LOG_DEBUG)
+	SrtLogLevelTrace   SrtLogLevel = SrtLogLevel(8)
+)
+
+var (
+	logCBPtr     unsafe.Pointer = nil
+	logCBPtrLock sync.Mutex
+)
+
+//export srtLogCBWrapper
+func srtLogCBWrapper(arg unsafe.Pointer, level C.int, file *C.char, line C.int, area, message *C.char) {
+	userCB := gopointer.Restore(arg).(LogCallBackFunc)
+	go userCB(SrtLogLevel(level), C.GoString(file), int(line), C.GoString(area), C.GoString(message))
+}
+
+func SrtSetLogLevel(level SrtLogLevel) {
+	C.srt_setloglevel(C.int(level))
+}
+
+func SrtSetLogHandler(cb LogCallBackFunc) {
+	ptr := gopointer.Save(cb)
+	C.srt_setloghandler(ptr, (*C.SRT_LOG_HANDLER_FN)(C.srtLogCB))
+	logCBPtrLock.Lock()
+	storeLogCBPtr(ptr)
+}
+
+func SrtUnsetLogHandler() {
+	C.srt_setloghandler(nil, nil)
+	storeLogCBPtr(nil)
+}
+
+func storeLogCBPtr(ptr unsafe.Pointer) {
+	logCBPtrLock.Lock()
+	defer logCBPtrLock.Unlock()
+	if logCBPtr != nil {
+		gopointer.Unref(logCBPtr)
+	}
+	logCBPtr = nil
+}

logging_c.go

@@ -0,0 +1,14 @@
+package srtgo
+
+/*
+#cgo LDFLAGS: -lsrt
+#include <srt/srt.h>
+
+extern void srtLogCBWrapper (void* opaque, int level, char* file, int line, char* area, char* message);
+
+void srtLogCB(void* opaque, int level, const char* file, int line, const char* area, const char* message)
+{
+	srtLogCBWrapper(opaque, level, (char*)file, line, (char*)area,(char*) message);
+}
+*/
+import "C"