feat: use runtime.AddCleanup and remove Destroy methods

README.md

@@ -32,7 +32,6 @@ func ExamplePJ_Forward() {
 	if err != nil {
 		panic(err)
 	}
-	defer pj.Destroy()
 
 	// Start with Zürich's WGS84 latitude/longitude.
 	zurich4326 := proj.NewCoord(47.374444, 8.541111, 408, 0)

context.go

@@ -28,36 +28,28 @@ func init() {
 
 // A Context is a context.
 type Context struct {
-	mutex     sync.Mutex
-	pjContext *C.PJ_CONTEXT
+	mutex      sync.Mutex
+	cPJContext *C.PJ_CONTEXT
 }
 
 // NewContext returns a new Context.
 func NewContext() *Context {
 	pjContext := C.proj_context_create()
 	C.proj_log_level(pjContext, C.PJ_LOG_NONE)
 	c := &Context{
-		pjContext: pjContext,
+		cPJContext: pjContext,
 	}
-	runtime.SetFinalizer(c, (*Context).Destroy)
+	runtime.AddCleanup(c, func(pjContext *C.PJ_CONTEXT) {
+		C.proj_context_destroy(pjContext)
+	}, pjContext)
 	return c
 }
 
-// Destroy frees all resources associated with c.
-func (c *Context) Destroy() {
-	c.Lock()
-	defer c.Unlock()
-	if c.pjContext != nil {
-		C.proj_context_destroy(c.pjContext)
-		c.pjContext = nil
-	}
-}
-
 // SetLogLevel sets the log level.
 func (c *Context) SetLogLevel(logLevel LogLevel) {
 	c.Lock()
 	defer c.Unlock()
-	C.proj_log_level(c.pjContext, C.PJ_LOG_LEVEL(logLevel))
+	C.proj_log_level(c.cPJContext, C.PJ_LOG_LEVEL(logLevel))
 }
 
 // SetSearchPaths sets the paths PROJ should be exploring to find the PROJ Data files.
@@ -73,7 +65,7 @@ func (c *Context) SetSearchPaths(paths []string) {
 	if len(paths) > 0 {
 		pathPtr = unsafe.Pointer(&cPaths[0])
 	}
-	C.proj_context_set_search_paths(c.pjContext, C.int(len(cPaths)), (**C.char)(pathPtr))
+	C.proj_context_set_search_paths(c.cPJContext, C.int(len(cPaths)), (**C.char)(pathPtr))
 }
 
 func (c *Context) Lock() {
@@ -93,10 +85,10 @@ func (c *Context) NewCRSToCRS(sourceCRS, targetCRS string, area *Area) (*PJ, err
 
 	var cArea *C.PJ_AREA
 	if area != nil {
-		cArea = area.pjArea
+		cArea = area.cPJArea
 	}
 
-	return c.newPJ(C.proj_create_crs_to_crs(c.pjContext, cSourceCRS, cTargetCRS, cArea))
+	return c.newPJ(C.proj_create_crs_to_crs(c.cPJContext, cSourceCRS, cTargetCRS, cArea))
 }
 
 // NewCRSToCRSFromPJ returns a new PJ from two CRSs.
@@ -123,10 +115,10 @@ func (c *Context) NewCRSToCRSFromPJ(sourcePJ, targetPJ *PJ, area *Area, options
 
 	var cArea *C.PJ_AREA
 	if area != nil {
-		cArea = area.pjArea
+		cArea = area.cPJArea
 	}
 
-	return c.newPJ(C.proj_create_crs_to_crs_from_pj(c.pjContext, sourcePJ.pj, targetPJ.pj, cArea, cOptionsPtr))
+	return c.newPJ(C.proj_create_crs_to_crs_from_pj(c.cPJContext, sourcePJ.cPJ, targetPJ.cPJ, cArea, cOptionsPtr))
 }
 
 // New returns a new PJ with the given definition.
@@ -137,7 +129,7 @@ func (c *Context) New(definition string) (*PJ, error) {
 	cDefinition := C.CString(definition)
 	defer C.free(unsafe.Pointer(cDefinition))
 
-	return c.newPJ(C.proj_create(c.pjContext, cDefinition))
+	return c.newPJ(C.proj_create(c.cPJContext, cDefinition))
 }
 
 // NewFromArgs returns a new PJ from args.
@@ -152,7 +144,7 @@ func (c *Context) NewFromArgs(args ...string) (*PJ, error) {
 		cArgs[i] = cArg
 	}
 
-	return c.newPJ(C.proj_create_argv(c.pjContext, (C.int)(len(cArgs)), (**C.char)(unsafe.Pointer(&cArgs[0]))))
+	return c.newPJ(C.proj_create_argv(c.cPJContext, (C.int)(len(cArgs)), (**C.char)(unsafe.Pointer(&cArgs[0]))))
 }
 
 func (c *Context) Unlock() {
@@ -163,7 +155,7 @@ func (c *Context) Unlock() {
 func (c *Context) errnoString(errno int) string {
 	c.Lock()
 	defer c.Unlock()
-	return C.GoString(C.proj_context_errno_string(c.pjContext, (C.int)(errno)))
+	return C.GoString(C.proj_context_errno_string(c.cPJContext, (C.int)(errno)))
 }
 
 // newError returns a new error with number errno.
@@ -177,14 +169,16 @@ func (c *Context) newError(errno int) *Error {
 // newPJ returns a new PJ or an error.
 func (c *Context) newPJ(cPJ *C.PJ) (*PJ, error) {
 	if cPJ == nil {
-		return nil, c.newError(int(C.proj_context_errno(c.pjContext)))
+		return nil, c.newError(int(C.proj_context_errno(c.cPJContext)))
 	}
 
 	pj := &PJ{
 		context: c,
-		pj:      cPJ,
+		cPJ:     cPJ,
 	}
-	runtime.SetFinalizer(pj, (*PJ).Destroy)
+	runtime.AddCleanup(pj, func(cPJ *C.PJ) {
+		C.proj_destroy(cPJ)
+	}, cPJ)
 	return pj, nil
 }
 

example_test.go

@@ -11,7 +11,6 @@ func ExamplePJ_Forward() {
 	if err != nil {
 		panic(err)
 	}
-	defer pj.Destroy()
 
 	// Start with Zürich's WGS84 latitude/longitude.
 	zurich4326 := proj.NewCoord(47.374444, 8.541111, 408, 0)

pj.go

@@ -20,7 +20,7 @@ const (
 // A PJ is a projection or a transformation.
 type PJ struct {
 	context *Context
-	pj      *C.PJ
+	cPJ     *C.PJ
 }
 
 // A PJInfo contains information about a PJ.
@@ -32,16 +32,6 @@ type PJInfo struct {
 	Accuracy    float64
 }
 
-// Destroy releases all resources associated with pj.
-func (pj *PJ) Destroy() {
-	pj.context.Lock()
-	defer pj.context.Unlock()
-	if pj.pj != nil {
-		C.proj_destroy(pj.pj)
-		pj.pj = nil
-	}
-}
-
 // Returns a new PJ instance whose axis order is the one expected for
 // visualization purposes. If the axis order of its source or target CRS is
 // northing, easting, then an axis swap operation will be inserted.
@@ -51,7 +41,7 @@ func (pj *PJ) Destroy() {
 func (pj *PJ) NormalizeForVisualization() (*PJ, error) {
 	pj.context.Lock()
 	defer pj.context.Unlock()
-	return pj.context.newPJ(C.proj_normalize_for_visualization(pj.context.pjContext, pj.pj))
+	return pj.context.newPJ(C.proj_normalize_for_visualization(pj.context.cPJContext, pj.cPJ))
 }
 
 // Forward transforms coord in the forward direction.
@@ -88,7 +78,7 @@ func (pj *PJ) ForwardFloat64Slices(float64Slices [][]float64) error {
 func (pj *PJ) Geod(a, b Coord) (float64, float64, float64) {
 	pj.context.Lock()
 	defer pj.context.Unlock()
-	cCoord := C.proj_geod(pj.pj, *(*C.PJ_COORD)(unsafe.Pointer(&a)), *(*C.PJ_COORD)(unsafe.Pointer(&b)))
+	cCoord := C.proj_geod(pj.cPJ, *(*C.PJ_COORD)(unsafe.Pointer(&a)), *(*C.PJ_COORD)(unsafe.Pointer(&b)))
 	cGeod := *(*C.PJ_GEOD)(unsafe.Pointer(&cCoord))
 	return (float64)(cGeod.s), (float64)(cGeod.a1), (float64)(cGeod.a2)
 }
@@ -97,15 +87,15 @@ func (pj *PJ) Geod(a, b Coord) (float64, float64, float64) {
 func (pj *PJ) GetLastUsedOperation() (*PJ, error) {
 	pj.context.Lock()
 	defer pj.context.Unlock()
-	return pj.context.newPJ(C.proj_trans_get_last_used_operation(pj.pj))
+	return pj.context.newPJ(C.proj_trans_get_last_used_operation(pj.cPJ))
 }
 
 // Info returns information about pj.
 func (pj *PJ) Info() PJInfo {
 	pj.context.Lock()
 	defer pj.context.Unlock()
 
-	cProjInfo := C.proj_pj_info(pj.pj)
+	cProjInfo := C.proj_pj_info(pj.cPJ)
 	return PJInfo{
 		ID:          C.GoString(cProjInfo.id),
 		Description: C.GoString(cProjInfo.description),
@@ -117,7 +107,7 @@ func (pj *PJ) Info() PJInfo {
 
 // IsCRS returns whether pj is a CRS.
 func (pj *PJ) IsCRS() bool {
-	return C.proj_is_crs(pj.pj) != 0
+	return C.proj_is_crs(pj.cPJ) != 0
 }
 
 // Inverse transforms coord in the inverse direction.
@@ -154,27 +144,27 @@ func (pj *PJ) InverseFloat64Slices(float64Slices [][]float64) error {
 func (pj *PJ) LPDist(a, b Coord) float64 {
 	pj.context.Lock()
 	defer pj.context.Unlock()
-	return (float64)(C.proj_lp_dist(pj.pj, *(*C.PJ_COORD)(unsafe.Pointer(&a)), *(*C.PJ_COORD)(unsafe.Pointer(&b))))
+	return (float64)(C.proj_lp_dist(pj.cPJ, *(*C.PJ_COORD)(unsafe.Pointer(&a)), *(*C.PJ_COORD)(unsafe.Pointer(&b))))
 }
 
 // LPZDist returns the geodesic distance between a and b in geodetic
 // coordinates, taking height above the ellipsoid into account.
 func (pj *PJ) LPZDist(a, b Coord) float64 {
 	pj.context.Lock()
 	defer pj.context.Unlock()
-	return (float64)(C.proj_lpz_dist(pj.pj, *(*C.PJ_COORD)(unsafe.Pointer(&a)), *(*C.PJ_COORD)(unsafe.Pointer(&b))))
+	return (float64)(C.proj_lpz_dist(pj.cPJ, *(*C.PJ_COORD)(unsafe.Pointer(&a)), *(*C.PJ_COORD)(unsafe.Pointer(&b))))
 }
 
 // Trans transforms a single Coord in place.
 func (pj *PJ) Trans(direction Direction, coord Coord) (Coord, error) {
 	pj.context.Lock()
 	defer pj.context.Unlock()
 
-	lastErrno := C.proj_errno_reset(pj.pj)
-	defer C.proj_errno_restore(pj.pj, lastErrno)
+	lastErrno := C.proj_errno_reset(pj.cPJ)
+	defer C.proj_errno_restore(pj.cPJ, lastErrno)
 
-	pjCoord := C.proj_trans(pj.pj, (C.PJ_DIRECTION)(direction), *(*C.PJ_COORD)(unsafe.Pointer(&coord)))
-	if errno := int(C.proj_errno(pj.pj)); errno != 0 {
+	pjCoord := C.proj_trans(pj.cPJ, (C.PJ_DIRECTION)(direction), *(*C.PJ_COORD)(unsafe.Pointer(&coord)))
+	if errno := int(C.proj_errno(pj.cPJ)); errno != 0 {
 		return Coord{}, pj.context.newError(errno)
 	}
 	return *(*Coord)(unsafe.Pointer(&pjCoord)), nil
@@ -189,10 +179,10 @@ func (pj *PJ) TransArray(direction Direction, coords []Coord) error {
 	pj.context.Lock()
 	defer pj.context.Unlock()
 
-	lastErrno := C.proj_errno_reset(pj.pj)
-	defer C.proj_errno_restore(pj.pj, lastErrno)
+	lastErrno := C.proj_errno_reset(pj.cPJ)
+	defer C.proj_errno_restore(pj.cPJ, lastErrno)
 
-	if errno := int(C.proj_trans_array(pj.pj, (C.PJ_DIRECTION)(direction), (C.size_t)(len(coords)), (*C.PJ_COORD)(unsafe.Pointer(&coords[0])))); errno != 0 {
+	if errno := int(C.proj_trans_array(pj.cPJ, (C.PJ_DIRECTION)(direction), (C.size_t)(len(coords)), (*C.PJ_COORD)(unsafe.Pointer(&coords[0])))); errno != 0 {
 		return pj.context.newError(errno)
 	}
 	return nil
@@ -204,11 +194,11 @@ func (pj *PJ) TransBounds(direction Direction, bounds Bounds, densifyPoints int)
 	defer pj.context.Unlock()
 
 	var transBounds Bounds
-	if C.proj_trans_bounds(pj.context.pjContext, pj.pj, (C.PJ_DIRECTION)(direction),
+	if C.proj_trans_bounds(pj.context.cPJContext, pj.cPJ, (C.PJ_DIRECTION)(direction),
 		(C.double)(bounds.XMin), (C.double)(bounds.YMin), (C.double)(bounds.XMax), (C.double)(bounds.YMax),
 		(*C.double)(&transBounds.XMin), (*C.double)(&transBounds.YMin), (*C.double)(&transBounds.XMax), (*C.double)(&transBounds.YMax),
 		C.int(densifyPoints)) == 0 {
-		return Bounds{}, pj.context.newError(int(C.proj_errno(pj.pj)))
+		return Bounds{}, pj.context.newError(int(C.proj_errno(pj.cPJ)))
 	}
 	return transBounds, nil
 }
@@ -275,16 +265,16 @@ func (pj *PJ) TransGeneric(direction Direction, x *float64, sx, nx int, y *float
 	pj.context.Lock()
 	defer pj.context.Unlock()
 
-	lastErrno := C.proj_errno_reset(pj.pj)
-	defer C.proj_errno_restore(pj.pj, lastErrno)
+	lastErrno := C.proj_errno_reset(pj.cPJ)
+	defer C.proj_errno_restore(pj.cPJ, lastErrno)
 
-	if int(C.proj_trans_generic(pj.pj, (C.PJ_DIRECTION)(direction),
+	if int(C.proj_trans_generic(pj.cPJ, (C.PJ_DIRECTION)(direction),
 		(*C.double)(x), C.size_t(sx), C.size_t(nx),
 		(*C.double)(y), C.size_t(sy), C.size_t(ny),
 		(*C.double)(z), C.size_t(sz), C.size_t(nz),
 		(*C.double)(m), C.size_t(sm), C.size_t(nm),
 	)) != max(nx, ny, nz, nm) {
-		return pj.context.newError(int(C.proj_errno(pj.pj)))
+		return pj.context.newError(int(C.proj_errno(pj.cPJ)))
 	}
 
 	return nil

proj.go

@@ -19,7 +19,7 @@ const (
 
 // An Area is an area.
 type Area struct {
-	pjArea *C.PJ_AREA
+	cPJArea *C.PJ_AREA
 }
 
 type Bounds struct {
@@ -40,23 +40,17 @@ type Error struct {
 
 // NewArea returns a new Area.
 func NewArea(westLonDegree, southLatDegree, eastLonDegree, northLatDegree float64) *Area {
-	pjArea := C.proj_area_create()
-	C.proj_area_set_bbox(pjArea, (C.double)(westLonDegree), (C.double)(southLatDegree), (C.double)(eastLonDegree), (C.double)(northLatDegree))
+	cPJArea := C.proj_area_create()
+	C.proj_area_set_bbox(cPJArea, (C.double)(westLonDegree), (C.double)(southLatDegree), (C.double)(eastLonDegree), (C.double)(northLatDegree))
 	a := &Area{
-		pjArea: pjArea,
+		cPJArea: cPJArea,
 	}
-	runtime.SetFinalizer(a, (*Area).Destroy)
+	runtime.AddCleanup(a, func(cPJArea *C.PJ_AREA) {
+		C.proj_area_destroy(cPJArea)
+	}, cPJArea)
 	return a
 }
 
-// Destroy frees all resources associated with a.
-func (a *Area) Destroy() {
-	if a.pjArea != nil {
-		C.proj_area_destroy(a.pjArea)
-		a.pjArea = nil
-	}
-}
-
 // NewCoord returns a new Coord.
 func NewCoord(x, y, z, m float64) Coord {
 	return Coord{x, y, z, m}