Make libusb optional

Foolishly, 'interface' is a reserved keyword on Windows according to
MSDN:

https://msdn.microsoft.com/en-us/library/2kb28261.aspx

Rename all 'interface' identifiers in the source code to avoid possible
conflicts. This is necessary because if libusb is not available, the
keyword is not undefined (#undef) by libusb.h any longer.

Signed-off-by: Marc Schink <jaylink-dev@marcschink.de>

10 files changed, 113 insertions, 36 deletions

diff --git a/configure.ac b/configure.ac
index 6462415..400d6db 100644
--- a/configure.ac
+++ b/configure.ac
@@ -50,7 +50,17 @@ PKG_PROG_PKG_CONFIG
 # Checks for libraries.
 
 # Check for libusb-1.0 which is always needed.
-PKG_CHECK_MODULES([libusb], [libusb-1.0 >= 1.0.9])
+PKG_CHECK_MODULES([libusb], [libusb-1.0 >= 1.0.9],
+	[HAVE_LIBUSB=yes], [HAVE_LIBUSB=no])
+
+AS_IF([test "x$HAVE_LIBUSB" = "xyes"],
+	[AC_DEFINE([HAVE_LIBUSB], [1], [Define to 1 if libusb is available.])])
+
+AS_IF([test "x$HAVE_LIBUSB" = "xyes"],
+	[JAYLINK_PKG_LIBS="libusb-1.0"])
+
+AM_CONDITIONAL([HAVE_LIBUSB],
+	[test "x$HAVE_LIBUSB" = "xyes"])
 
 # Checks for header files.
 
@@ -93,6 +103,7 @@ AS_CASE([$host_os], [mingw*], [JAYLINK_LIBS="$JAYLINK_LIBS -lws2_32"])
 AC_SUBST([JAYLINK_CFLAGS])
 AC_SUBST([JAYLINK_LDFLAGS])
 AC_SUBST([JAYLINK_LIBS])
+AC_SUBST([JAYLINK_PKG_LIBS])
 
 AC_CONFIG_FILES([Makefile])
 AC_CONFIG_FILES([libjaylink/Makefile])
diff --git a/libjaylink.pc.in b/libjaylink.pc.in
index 2b156ab..a5efd3a 100644
--- a/libjaylink.pc.in
+++ b/libjaylink.pc.in
@@ -6,6 +6,6 @@ includedir=@includedir@
 Name: libjaylink
 Description: Library to access J-Link devices
 Version: @VERSION@
-Requires.private: libusb-1.0
+Requires.private: @JAYLINK_PKG_LIBS@
 Libs: -L${libdir} -ljaylink
 Cflags: -I${includedir}
diff --git a/libjaylink/Makefile.am b/libjaylink/Makefile.am
index 3ed3c74..62c5489 100644
--- a/libjaylink/Makefile.am
+++ b/libjaylink/Makefile.am
@@ -33,7 +33,6 @@ libjaylink_la_SOURCES = \
 	device.c \
 	discovery.c \
 	discovery_tcp.c \
-	discovery_usb.c \
 	emucom.c \
 	error.c \
 	fileio.c \
@@ -47,12 +46,17 @@ libjaylink_la_SOURCES = \
 	target.c \
 	transport.c \
 	transport_tcp.c \
-	transport_usb.c \
 	util.c \
 	version.c
 
-libjaylink_la_CFLAGS = $(JAYLINK_CFLAGS) $(libusb_CFLAGS)
+libjaylink_la_CFLAGS = $(JAYLINK_CFLAGS)
 libjaylink_la_LDFLAGS = $(JAYLINK_LDFLAGS) -no-undefined
-libjaylink_la_LIBADD = $(JAYLINK_LIBS) $(libusb_LIBS)
+libjaylink_la_LIBADD = $(JAYLINK_LIBS)
+
+if HAVE_LIBUSB
+libjaylink_la_SOURCES += discovery_usb.c transport_usb.c
+libjaylink_la_CFLAGS += $(libusb_CFLAGS)
+libjaylink_la_LIBADD += $(libusb_LIBS)
+endif
 
 noinst_HEADERS = libjaylink-internal.h
diff --git a/libjaylink/core.c b/libjaylink/core.c
index 9f0d8b1..e2d1e8f 100644
--- a/libjaylink/core.c
+++ b/libjaylink/core.c
@@ -17,12 +17,18 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include <stdlib.h>
 #include <stdbool.h>
 #ifdef _WIN32
 #include <winsock2.h>
 #endif
+#ifdef HAVE_LIBUSB
 #include <libusb.h>
+#endif
 
 #include "libjaylink.h"
 #include "libjaylink-internal.h"
@@ -98,22 +104,28 @@ JAYLINK_API int jaylink_init(struct jaylink_context **ctx)
 	if (!context)
 		return JAYLINK_ERR_MALLOC;
 
+#ifdef HAVE_LIBUSB
 	if (libusb_init(&context->usb_ctx) != LIBUSB_SUCCESS) {
 		free(context);
 		return JAYLINK_ERR;
 	}
+#endif
 
 #ifdef _WIN32
 	ret = WSAStartup(MAKEWORD(2, 2), &wsa_data);
 
 	if (ret != 0) {
+#ifdef HAVE_LIBUSB
 		libusb_exit(context->usb_ctx);
+#endif
 		free(context);
 		return JAYLINK_ERR;
 	}
 
 	if (LOBYTE(wsa_data.wVersion) != 2 || HIBYTE(wsa_data.wVersion) != 2) {
+#ifdef HAVE_LIBUSB
 		libusb_exit(context->usb_ctx);
+#endif
 		free(context);
 		return JAYLINK_ERR;
 	}
@@ -170,11 +182,12 @@ JAYLINK_API int jaylink_exit(struct jaylink_context *ctx)
 	list_free(ctx->discovered_devs);
 	list_free(ctx->devs);
 
+#ifdef HAVE_LIBUSB
 	libusb_exit(ctx->usb_ctx);
+#endif
 #ifdef _WIN32
 	WSACleanup();
 #endif
-
 	free(ctx);
 
 	return JAYLINK_OK;
@@ -193,8 +206,10 @@ JAYLINK_API int jaylink_exit(struct jaylink_context *ctx)
 JAYLINK_API bool jaylink_library_has_cap(enum jaylink_capability cap)
 {
 	switch (cap) {
+#ifdef HAVE_LIBUSB
 	case JAYLINK_CAP_HIF_USB:
 		return true;
+#endif
 	default:
 		return false;
 	}
diff --git a/libjaylink/device.c b/libjaylink/device.c
index 5b79b43..a3bddf6 100644
--- a/libjaylink/device.c
+++ b/libjaylink/device.c
@@ -17,6 +17,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
 #include <stdlib.h>
 #include <stdint.h>
 #include <stdbool.h>
@@ -27,7 +31,9 @@
 #include <sys/socket.h>
 #include <arpa/inet.h>
 #endif
+#ifdef HAVE_LIBUSB
 #include <libusb.h>
+#endif
 
 #include "libjaylink.h"
 #include "libjaylink-internal.h"
@@ -206,7 +212,7 @@ JAYLINK_API int jaylink_device_get_host_interface(
 	if (!dev || !iface)
 		return JAYLINK_ERR_ARG;
 
-	*iface = dev->interface;
+	*iface = dev->iface;
 
 	return JAYLINK_OK;
 }
@@ -267,12 +273,16 @@ JAYLINK_API int jaylink_device_get_usb_address(
 	if (!dev || !address)
 		return JAYLINK_ERR_ARG;
 
-	if (dev->interface != JAYLINK_HIF_USB)
+	if (dev->iface != JAYLINK_HIF_USB)
 		return JAYLINK_ERR_NOT_SUPPORTED;
 
+#ifdef HAVE_LIBUSB
 	*address = dev->usb_address;
 
 	return JAYLINK_OK;
+#else
+	return JAYLINK_ERR_NOT_SUPPORTED;
+#endif
 }
 
 /**
@@ -295,7 +305,7 @@ JAYLINK_API int jaylink_device_get_ipv4_address(
 	if (!dev || !address)
 		return JAYLINK_ERR_ARG;
 
-	if (dev->interface != JAYLINK_HIF_TCP)
+	if (dev->iface != JAYLINK_HIF_TCP)
 		return JAYLINK_ERR_NOT_SUPPORTED;
 
 	memcpy(address, dev->ipv4_address, sizeof(dev->ipv4_address));
@@ -325,7 +335,7 @@ JAYLINK_API int jaylink_device_get_mac_address(
 	if (!dev || !address)
 		return JAYLINK_ERR_ARG;
 
-	if (dev->interface != JAYLINK_HIF_TCP)
+	if (dev->iface != JAYLINK_HIF_TCP)
 		return JAYLINK_ERR_NOT_SUPPORTED;
 
 	if (!dev->has_mac_address)
@@ -361,7 +371,7 @@ JAYLINK_API int jaylink_device_get_hardware_version(
 	if (!dev || !version)
 		return JAYLINK_ERR_ARG;
 
-	if (dev->interface != JAYLINK_HIF_TCP)
+	if (dev->iface != JAYLINK_HIF_TCP)
 		return JAYLINK_ERR_NOT_SUPPORTED;
 
 	if (!dev->has_hw_version)
@@ -394,7 +404,7 @@ JAYLINK_API int jaylink_device_get_product_name(
 	if (!dev || !name)
 		return JAYLINK_ERR_ARG;
 
-	if (dev->interface != JAYLINK_HIF_TCP)
+	if (dev->iface != JAYLINK_HIF_TCP)
 		return JAYLINK_ERR_NOT_SUPPORTED;
 
 	if (!dev->has_product_name)
@@ -427,7 +437,7 @@ JAYLINK_API int jaylink_device_get_nickname(const struct jaylink_device *dev,
 	if (!dev || !nickname)
 		return JAYLINK_ERR_ARG;
 
-	if (dev->interface != JAYLINK_HIF_TCP)
+	if (dev->iface != JAYLINK_HIF_TCP)
 		return JAYLINK_ERR_NOT_SUPPORTED;
 
 	if (!dev->has_nickname)
@@ -478,19 +488,21 @@ JAYLINK_API void jaylink_unref_device(struct jaylink_device *dev)
 		ctx = dev->ctx;
 		ctx->devs = list_remove(dev->ctx->devs, dev);
 
-		if (dev->interface == JAYLINK_HIF_USB) {
+		if (dev->iface == JAYLINK_HIF_USB) {
+#ifdef HAVE_LIBUSB
 			log_dbg(ctx, "Device destroyed (bus:address = "
 				"%03u:%03u).",
 				libusb_get_bus_number(dev->usb_dev),
 				libusb_get_device_address(dev->usb_dev));
 
 			libusb_unref_device(dev->usb_dev);
-		} else if (dev->interface == JAYLINK_HIF_TCP) {
+#endif
+		} else if (dev->iface == JAYLINK_HIF_TCP) {
 			log_dbg(ctx, "Device destroyed (IPv4 address = %s).",
 				dev->ipv4_address);
 		} else {
 			log_err(ctx, "BUG: Invalid host interface: %u.",
-				dev->interface);
+				dev->iface);
 		}
 
 		free(dev);
diff --git a/libjaylink/discovery.c b/libjaylink/discovery.c
index 7b4808b..1ac96e7 100644
--- a/libjaylink/discovery.c
+++ b/libjaylink/discovery.c
@@ -19,6 +19,9 @@
 
 #include <stdlib.h>
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 #include "libjaylink.h"
 #include "libjaylink-internal.h"
 
@@ -79,6 +82,7 @@ JAYLINK_API int jaylink_discovery_scan(struct jaylink_context *ctx,
 
 	clear_discovery_list(ctx);
 
+#ifdef HAVE_LIBUSB
 	if (ifaces & JAYLINK_HIF_USB) {
 		ret = discovery_usb_scan(ctx);
 
@@ -87,6 +91,7 @@ JAYLINK_API int jaylink_discovery_scan(struct jaylink_context *ctx,
 			return ret;
 		}
 	}
+#endif
 
 	if (ifaces & JAYLINK_HIF_TCP) {
 		ret = discovery_tcp_scan(ctx);
diff --git a/libjaylink/discovery_tcp.c b/libjaylink/discovery_tcp.c
index 25e7732..555e121 100644
--- a/libjaylink/discovery_tcp.c
+++ b/libjaylink/discovery_tcp.c
@@ -61,7 +61,7 @@ static bool compare_devices(const void *a, const void *b)
 	dev = a;
 	new_dev = b;
 
-	if (dev->interface != JAYLINK_HIF_TCP)
+	if (dev->iface != JAYLINK_HIF_TCP)
 		return false;
 
 	if (memcmp(dev->ipv4_address, new_dev->ipv4_address,
@@ -195,7 +195,7 @@ static struct jaylink_device *probe_device(struct jaylink_context *ctx,
 		return NULL;
 	}
 
-	dev->interface = JAYLINK_HIF_TCP;
+	dev->iface = JAYLINK_HIF_TCP;
 
 	dev->serial_number = tmp.serial_number;
 	dev->valid_serial_number = tmp.valid_serial_number;
diff --git a/libjaylink/discovery_usb.c b/libjaylink/discovery_usb.c
index 409ca75..48d5322 100644
--- a/libjaylink/discovery_usb.c
+++ b/libjaylink/discovery_usb.c
@@ -102,7 +102,7 @@ static bool compare_devices(const void *a, const void *b)
 	dev = a;
 	usb_dev = b;
 
-	if (dev->interface != JAYLINK_HIF_USB)
+	if (dev->iface != JAYLINK_HIF_USB)
 		return false;
 
 	if (dev->usb_dev == usb_dev)
@@ -232,7 +232,7 @@ static struct jaylink_device *probe_device(struct jaylink_context *ctx,
 		return NULL;
 	}
 
-	dev->interface = JAYLINK_HIF_USB;
+	dev->iface = JAYLINK_HIF_USB;
 	dev->usb_dev = libusb_ref_device(usb_dev);
 	dev->usb_address = usb_address;
 	dev->serial_number = serial_number;
diff --git a/libjaylink/libjaylink-internal.h b/libjaylink/libjaylink-internal.h
index e48d192..c5b128b 100644
--- a/libjaylink/libjaylink-internal.h
+++ b/libjaylink/libjaylink-internal.h
@@ -31,7 +31,14 @@
 #include <sys/socket.h>
 #include <arpa/inet.h>
 #endif
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#ifdef HAVE_LIBUSB
 #include <libusb.h>
+#endif
 
 #include "libjaylink.h"
 
@@ -52,8 +59,10 @@
 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
 
 struct jaylink_context {
+#ifdef HAVE_LIBUSB
 	/** libusb context. */
 	struct libusb_context *usb_ctx;
+#endif
 	/**
 	 * List of allocated device instances.
 	 *
@@ -78,7 +87,7 @@ struct jaylink_device {
 	/** Number of references held on this device instance. */
 	size_t ref_count;
 	/** Host interface. */
-	enum jaylink_host_interface interface;
+	enum jaylink_host_interface iface;
 	/**
 	 * Serial number of the device.
 	 *
@@ -88,10 +97,12 @@ struct jaylink_device {
 	uint32_t serial_number;
 	/** Indicates whether the serial number is valid. */
 	bool valid_serial_number;
+#ifdef HAVE_LIBUSB
 	/** libusb device instance. */
 	struct libusb_device *usb_dev;
 	/** USB address of the device. */
 	uint8_t usb_address;
+#endif
 	/**
 	 * IPv4 address.
 	 *
@@ -169,6 +180,7 @@ struct jaylink_device_handle {
 	 * write operations only.
 	 */
 	size_t write_pos;
+#ifdef HAVE_LIBUSB
 	/** libusb device handle. */
 	struct libusb_device_handle *usb_devh;
 	/** USB interface number of the device. */
@@ -177,6 +189,7 @@ struct jaylink_device_handle {
 	uint8_t endpoint_in;
 	/** USB interface OUT endpoint of the device. */
 	uint8_t endpoint_out;
+#endif
 	/**
 	 * Socket descriptor.
 	 *
diff --git a/libjaylink/transport.c b/libjaylink/transport.c
index 11837a4..0c276b3 100644
--- a/libjaylink/transport.c
+++ b/libjaylink/transport.c
@@ -22,6 +22,9 @@
 #include <stdbool.h>
 #include <string.h>
 
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
 #include "libjaylink.h"
 #include "libjaylink-internal.h"
 
@@ -47,16 +50,18 @@ JAYLINK_PRIV int transport_open(struct jaylink_device_handle *devh)
 {
 	int ret;
 
-	switch (devh->dev->interface) {
+	switch (devh->dev->iface) {
+#ifdef HAVE_LIBUSB
 	case JAYLINK_HIF_USB:
 		ret = transport_usb_open(devh);
 		break;
+#endif
 	case JAYLINK_HIF_TCP:
 		ret = transport_tcp_open(devh);
 		break;
 	default:
 		log_err(devh->dev->ctx, "BUG: Invalid host interface: %u.",
-			devh->dev->interface);
+			devh->dev->iface);
 		return JAYLINK_ERR;
 	}
 
@@ -78,16 +83,18 @@ JAYLINK_PRIV int transport_close(struct jaylink_device_handle *devh)
 {
 	int ret;
 
-	switch (devh->dev->interface) {
+	switch (devh->dev->iface) {
+#ifdef HAVE_LIBUSB
 	case JAYLINK_HIF_USB:
 		ret = transport_usb_close(devh);
 		break;
+#endif
 	case JAYLINK_HIF_TCP:
 		ret = transport_tcp_close(devh);
 		break;
 	default:
 		log_err(devh->dev->ctx, "BUG: Invalid host interface: %u.",
-			devh->dev->interface);
+			devh->dev->iface);
 		return JAYLINK_ERR;
 	}
 
@@ -114,16 +121,18 @@ JAYLINK_PRIV int transport_start_write(struct jaylink_device_handle *devh,
 {
 	int ret;
 
-	switch (devh->dev->interface) {
+	switch (devh->dev->iface) {
+#ifdef HAVE_LIBUSB
 	case JAYLINK_HIF_USB:
 		ret = transport_usb_start_write(devh, length, has_command);
 		break;
+#endif
 	case JAYLINK_HIF_TCP:
 		ret = transport_tcp_start_write(devh, length, has_command);
 		break;
 	default:
 		log_err(devh->dev->ctx, "BUG: Invalid host interface: %u.",
-			devh->dev->interface);
+			devh->dev->iface);
 		return JAYLINK_ERR;
 	}
 
@@ -148,16 +157,18 @@ JAYLINK_PRIV int transport_start_read(struct jaylink_device_handle *devh,
 {
 	int ret;
 
-	switch (devh->dev->interface) {
+	switch (devh->dev->iface) {
+#ifdef HAVE_LIBUSB
 	case JAYLINK_HIF_USB:
 		ret = transport_usb_start_read(devh, length);
 		break;
+#endif
 	case JAYLINK_HIF_TCP:
 		ret = transport_tcp_start_read(devh, length);
 		break;
 	default:
 		log_err(devh->dev->ctx, "BUG: Invalid host interface: %u.",
-			devh->dev->interface);
+			devh->dev->iface);
 		return JAYLINK_ERR;
 	}
 
@@ -189,18 +200,20 @@ JAYLINK_PRIV int transport_start_write_read(struct jaylink_device_handle *devh,
 {
 	int ret;
 
-	switch (devh->dev->interface) {
+	switch (devh->dev->iface) {
+#ifdef HAVE_LIBUSB
 	case JAYLINK_HIF_USB:
 		ret = transport_usb_start_write_read(devh, write_length,
 			read_length, has_command);
 		break;
+#endif
 	case JAYLINK_HIF_TCP:
 		ret = transport_tcp_start_write_read(devh, write_length,
 			read_length, has_command);
 		break;
 	default:
 		log_err(devh->dev->ctx, "BUG: Invalid host interface: %u.",
-			devh->dev->interface);
+			devh->dev->iface);
 		return JAYLINK_ERR;
 	}
 
@@ -235,16 +248,18 @@ JAYLINK_PRIV int transport_write(struct jaylink_device_handle *devh,
 {
 	int ret;
 
-	switch (devh->dev->interface) {
+	switch (devh->dev->iface) {
+#ifdef HAVE_LIBUSB
 	case JAYLINK_HIF_USB:
 		ret = transport_usb_write(devh, buffer, length);
 		break;
+#endif
 	case JAYLINK_HIF_TCP:
 		ret = transport_tcp_write(devh, buffer, length);
 		break;
 	default:
 		log_err(devh->dev->ctx, "BUG: Invalid host interface: %u.",
-			devh->dev->interface);
+			devh->dev->iface);
 		return JAYLINK_ERR;
 	}
 
@@ -275,16 +290,18 @@ JAYLINK_PRIV int transport_read(struct jaylink_device_handle *devh,
 {
 	int ret;
 
-	switch (devh->dev->interface) {
+	switch (devh->dev->iface) {
+#ifdef HAVE_LIBUSB
 	case JAYLINK_HIF_USB:
 		ret = transport_usb_read(devh, buffer, length);
 		break;
+#endif
 	case JAYLINK_HIF_TCP:
 		ret = transport_tcp_read(devh, buffer, length);
 		break;
 	default:
 		log_err(devh->dev->ctx, "BUG: Invalid host interface: %u.",
-			devh->dev->interface);
+			devh->dev->iface);
 		return JAYLINK_ERR;
 	}