Golang C.free函数代码示例

// Set geographic coordinate system
func (sr SpatialReference) SetGeographicCS(
	geogName, datumName, spheroidName string,
	semiMajor, flattening float64,
	pmName string,
	offset float64,
	angularUnits string,
	toRadians float64,
) error {
	cGeogName := C.CString(geogName)
	defer C.free(unsafe.Pointer(cGeogName))
	cDatumName := C.CString(datumName)
	defer C.free(unsafe.Pointer(cDatumName))
	cSpheroidName := C.CString(spheroidName)
	defer C.free(unsafe.Pointer(cSpheroidName))
	cPMName := C.CString(pmName)
	defer C.free(unsafe.Pointer(cPMName))
	cAngularUnits := C.CString(angularUnits)
	defer C.free(unsafe.Pointer(cAngularUnits))
	return C.OSRSetGeogCS(
		sr.cval,
		cGeogName,
		cDatumName,
		cSpheroidName,
		C.double(semiMajor),
		C.double(flattening),
		cPMName,
		C.double(offset),
		cAngularUnits,
		C.double(toRadians),
	).Err()
}

func connect(conninfo string) (*PgConn, error) {
	cs := C.CString(conninfo)
	defer C.free(unsafe.Pointer(cs))
	conn := C.PQconnectdb(cs)
	if C.PQstatus(conn) != C.CONNECTION_OK {
		cerr := C.PQerrorMessage(conn)
		err := fmt.Errorf("connection failed: %s", C.GoString(cerr))
		C.PQfinish(conn)
		return nil, err
	}

	// TODO: support other encodings?
	pname := C.CString("client_encoding")
	defer C.free(unsafe.Pointer(pname))
	cenc := C.PQparameterStatus(conn, pname)
	if cenc == nil {
		err := errors.New("connection failed: no client encoding")
		C.PQfinish(conn)
		return nil, err
	}
	if enc := C.GoString(cenc); enc != "UTF8" {
		err := fmt.Errorf(
			"connection failed: client encoding not supported: %s", enc)
		C.PQfinish(conn)
		return nil, err
	}

	// one-line error message
	C.PQsetErrorVerbosity(conn, C.PQERRORS_TERSE)

	return &PgConn{conn: conn, conninfo: conninfo}, nil
}

func OpenWithFallback(fromCode string, toCode string, fallbackPolicy int) (ic *Iconv, err error) {
	var pIconv C.iconv_t

	toCodeCharPtr := C.CString(toCode)
	defer C.free(unsafe.Pointer(toCodeCharPtr))
	fromCodeCharPtr := C.CString(fromCode)
	defer C.free(unsafe.Pointer(fromCodeCharPtr))

	pIconv, err = C.iconv_open(toCodeCharPtr, fromCodeCharPtr)
	if err == nil {
		if pIconv == nil {
			err = NilIconvPointer
			return
		}
		if fallbackPolicy == DISCARD_UNRECOGNIZED {
			ic = &Iconv{pIconv: pIconv, fallbackPolicy: fallbackPolicy, fallback: fallbackDiscardUnrecognized}
		} else if fallbackPolicy == KEEP_UNRECOGNIZED {
			ic = &Iconv{pIconv: pIconv, fallbackPolicy: fallbackPolicy, fallback: fallbackKeepIntactUnrecognized}
		} else if fallbackPolicy == NEXT_ENC_UNRECOGNIZED {
			ic = &Iconv{pIconv: pIconv, fallbackPolicy: fallbackPolicy}
		} else {
			err = InvalidFallbackPolicy
		}
	}
	return
}

func (v *Reference) Rename(name string, force bool, sig *Signature, msg string) (*Reference, error) {
	var ptr *C.git_reference
	cname := C.CString(name)
	defer C.free(unsafe.Pointer(cname))

	csig := sig.toC()
	defer C.free(unsafe.Pointer(csig))

	var cmsg *C.char
	if msg == "" {
		cmsg = nil
	} else {
		cmsg = C.CString(msg)
		defer C.free(unsafe.Pointer(cmsg))
	}

	runtime.LockOSThread()
	defer runtime.UnlockOSThread()

	ret := C.git_reference_rename(&ptr, v.ptr, cname, cbool(force), csig, cmsg)

	if ret < 0 {
		return nil, MakeGitError(ret)
	}

	return newReferenceFromC(ptr), nil
}

func (provider *Provider) AddProbe(function string, name string, signature ...reflect.Kind) Probe {
	cFunction := C.CString(function)
	cName := C.CString(name)
	defer C.free(unsafe.Pointer(cFunction))
	defer C.free(unsafe.Pointer(cName))

	cTypes := make([]*C.char, len(signature))

	for i, kind := range signature {
		switch kind {
		case reflect.Int:
			cTypes[i] = C.CString("int")
			defer C.free(unsafe.Pointer(cTypes[i]))
		case reflect.String:
			cTypes[i] = C.CString("char *")
			defer C.free(unsafe.Pointer(cTypes[i]))
		default:
			cTypes[i] = nil
		}
	}

	probedef := C.usdt_create_probe(cFunction, cName, C.size_t(len(signature)), &cTypes[0])
	C.usdt_provider_add_probe(provider.provider_t, probedef)

	newProbe := Probe{
		function,
		name,
		probedef,
	}

	provider.Probes = append(provider.Probes, newProbe)

	return newProbe
}

func sqlOpen(name string, flags int, vfs string) (conn *sqlConnection, rc int) {
	conn = new(sqlConnection)

	p := C.CString(name)
	if len(vfs) > 0 {
		q := C.CString(vfs)
		rc = int(C.sqlite3_open_v2(p, &conn.handle, C.int(flags), q))
		C.free(unsafe.Pointer(q))
	} else {
		rc = int(C.sqlite3_open_v2(p, &conn.handle, C.int(flags), nil))
	}
	C.free(unsafe.Pointer(p))

	// We could get a handle even if there's an error, see
	// http://www.sqlite.org/c3ref/open.html for details.
	// Initially we didn't want to return a connection on
	// error, but we actually have to since we want to fill
	// in a SystemError struct. Sigh.
	//	if rc != StatusOk && conn.handle != nil {
	//		_ = conn.sqlClose();
	//		conn = nil;
	//	}

	return
}

// GetApproximateSizes returns the approximate number of bytes of file system
// space used by one or more key ranges.
//
// The keys counted will begin at Range.Start and end on the key before
// Range.Limit.
func (db *DB) GetApproximateSizes(ranges []Range) []uint64 {
	starts := make([]*C.char, len(ranges))
	limits := make([]*C.char, len(ranges))
	startLens := make([]C.size_t, len(ranges))
	limitLens := make([]C.size_t, len(ranges))
	for i, r := range ranges {
		starts[i] = C.CString(string(r.Start))
		startLens[i] = C.size_t(len(r.Start))
		limits[i] = C.CString(string(r.Limit))
		limitLens[i] = C.size_t(len(r.Limit))
	}
	sizes := make([]uint64, len(ranges))
	numranges := C.int(len(ranges))
	startsPtr := &starts[0]
	limitsPtr := &limits[0]
	startLensPtr := &startLens[0]
	limitLensPtr := &limitLens[0]
	sizesPtr := (*C.uint64_t)(&sizes[0])
	C.hyperleveldb_rocksdb_approximate_sizes(
		db.Ldb, numranges, startsPtr, startLensPtr,
		limitsPtr, limitLensPtr, sizesPtr)
	for i := range ranges {
		C.free(unsafe.Pointer(starts[i]))
		C.free(unsafe.Pointer(limits[i]))
	}
	return sizes
}

// ConfigureFD sets up the tun device using a file descriptor.
func ConfigureFD(tunFd int, tunMTU int, ipaddr, netmask, udpgw string, d dialer) error {
	if d == nil {
		d = dummyDialer
	}

	Dialer = d
	udpGwServerAddress = udpgw

	ctunFd := C.int(tunFd)
	ctunMTU := C.int(tunMTU)
	cipaddr := C.CString(ipaddr)
	cnetmask := C.CString(netmask)
	cudpgw_addr := C.CString(udpgw)

	defer func() {
		C.free(unsafe.Pointer(cipaddr))
		C.free(unsafe.Pointer(cnetmask))
		C.free(unsafe.Pointer(cudpgw_addr))
	}()

	log.Printf("Configuring with file descriptor...")

	if err_t := C.configure_fd(ctunFd, ctunMTU, cipaddr, cnetmask, cudpgw_addr); err_t != C.ERR_OK {
		return errors.New("Failed to configure device.")
	}

	return nil
}

// ConfigureTUN sets up the tun device, this is equivalent to the
// badvpn-tun2socks configuration, except for the --socks-server-addr.
func ConfigureTUN(tundev, ipaddr, netmask, udpgw string, d dialer) error {
	if d == nil {
		d = dummyDialer
	}

	Dialer = d
	udpGwServerAddress = udpgw

	ctundev := C.CString(tundev)
	cipaddr := C.CString(ipaddr)
	cnetmask := C.CString(netmask)
	cudpgw_addr := C.CString(udpgw)

	defer func() {
		C.free(unsafe.Pointer(ctundev))
		C.free(unsafe.Pointer(cipaddr))
		C.free(unsafe.Pointer(cnetmask))
		C.free(unsafe.Pointer(cudpgw_addr))
	}()

	log.Printf("Configuring with TUN device...")

	if err_t := C.configure_tun(ctundev, cipaddr, cnetmask, cudpgw_addr); err_t != C.ERR_OK {
		return errors.New("Failed to configure device.")
	}

	return nil
}

// GetRunningSlice attempts to retrieve the name of the systemd slice in which
// the current process is running.
// This function is a wrapper around the libsystemd C library; if it cannot be
// opened, an error is returned.
func GetRunningSlice() (slice string, err error) {
	var h *libHandle
	h, err = getHandle()
	if err != nil {
		return
	}
	defer func() {
		if err1 := h.Close(); err1 != nil {
			err = err1
		}
	}()

	sym := C.CString("sd_pid_get_slice")
	defer C.free(unsafe.Pointer(sym))
	sd_pid_get_slice := C.dlsym(h.handle, sym)
	if sd_pid_get_slice == nil {
		err = fmt.Errorf("error resolving sd_pid_get_slice function")
		return
	}

	var s string
	sl := C.CString(s)
	defer C.free(unsafe.Pointer(sl))

	ret := C.my_sd_pid_get_slice(sd_pid_get_slice, 0, &sl)
	if ret < 0 {
		err = fmt.Errorf("error calling sd_pid_get_slice: %v", syscall.Errno(-ret))
		return
	}

	return C.GoString(sl), nil
}

// CurrentUnitName attempts to retrieve the name of the systemd system unit
// from which the calling process has been invoked. It wraps the systemd
// `sd_pid_get_unit` call, with the same caveat: for processes not part of a
// systemd system unit, this function will return an error.
func CurrentUnitName() (unit string, err error) {
	var h *libHandle
	h, err = getHandle()
	if err != nil {
		return
	}
	defer func() {
		if err1 := h.Close(); err1 != nil {
			err = err1
		}
	}()

	sym := C.CString("sd_pid_get_unit")
	defer C.free(unsafe.Pointer(sym))
	sd_pid_get_unit := C.dlsym(h.handle, sym)
	if sd_pid_get_unit == nil {
		err = fmt.Errorf("error resolving sd_pid_get_unit function")
		return
	}

	var s string
	u := C.CString(s)
	defer C.free(unsafe.Pointer(u))

	ret := C.my_sd_pid_get_unit(sd_pid_get_unit, 0, &u)
	if ret < 0 {
		err = fmt.Errorf("error calling sd_pid_get_unit: %v", syscall.Errno(-ret))
		return
	}

	unit = C.GoString(u)
	return
}

// LoadHTML loads the given content string with the specified baseURI. The MIME
// type of the document will be "text/html".
//
// See also: webkit_web_view_load_html at
// http://webkitgtk.org/reference/webkit2gtk/stable/WebKitWebView.html#webkit-web-view-load-html
func (v *WebView) LoadHTML(content, baseURI string) {
	cContent := C.CString(content)
	defer C.free(unsafe.Pointer(cContent))
	cBaseURI := C.CString(baseURI)
	defer C.free(unsafe.Pointer(cBaseURI))
	C.webkit_web_view_load_html(v.webView, (*C.gchar)(cContent), (*C.gchar)(cBaseURI))
}

// Sets the authority for a node
func (sr SpatialReference) SetAuthority(target, authority string, code int) error {
	cTarget := C.CString(target)
	defer C.free(unsafe.Pointer(cTarget))
	cAuthority := C.CString(authority)
	defer C.free(unsafe.Pointer(cAuthority))
	return C.OSRSetAuthority(sr.cval, cTarget, cAuthority, C.int(code)).Err()
}

// Set up the vertical coordinate system
func (sr SpatialReference) SetVerticalCS(csName, datumName string, datumType int) error {
	cCSName := C.CString(csName)
	defer C.free(unsafe.Pointer(cCSName))
	cDatumName := C.CString(datumName)
	defer C.free(unsafe.Pointer(cDatumName))
	return C.OSRSetVertCS(sr.cval, cCSName, cDatumName, C.int(datumType)).Err()
}

// function that lists all the xattrs for an object, since xattrs are
// a k-v pair, this function returns a map of k-v pairs on
// success, error code on failure
func (ioctx *IOContext) ListXattrs(oid string) (map[string][]byte, error) {
	c_oid := C.CString(oid)
	defer C.free(unsafe.Pointer(c_oid))

	var it C.rados_xattrs_iter_t

	ret := C.rados_getxattrs(ioctx.ioctx, c_oid, &it)
	if ret < 0 {
		return nil, GetRadosError(ret)
	}
	defer func() { C.rados_getxattrs_end(it) }()
	m := make(map[string][]byte)
	for {
		var c_name, c_val *C.char
		var c_len C.size_t
		defer C.free(unsafe.Pointer(c_name))
		defer C.free(unsafe.Pointer(c_val))

		ret := C.rados_getxattrs_next(it, &c_name, &c_val, &c_len)
		if ret < 0 {
			return nil, GetRadosError(ret)
		}
		// rados api returns a null name,val & 0-length upon
		// end of iteration
		if c_name == nil {
			return m, nil // stop iteration
		}
		m[C.GoString(c_name)] = C.GoBytes(unsafe.Pointer(c_val), (C.int)(c_len))
	}
}