Add a devinfo event.

The firmware version and serial number are stored in the final block
of each dive. That makes it very tricky to support the devinfo event
correctly. For an efficient implementation of the fingerprint feature,
the devinfo event should be emitted before downloading the manifests
or the dives. Fortunately it turns out it is actually possible to
retrieve the firmware version and serial number independently, using
the special identifier command.

src/shearwater_common.c

@@ -441,3 +441,42 @@ shearwater_common_download (shearwater_common_device_t *device, dc_buffer_t *buf
 
 	return DC_STATUS_SUCCESS;
 }
+
+
+dc_status_t
+shearwater_common_identifier (shearwater_common_device_t *device, dc_buffer_t *buffer, unsigned int id)
+{
+	dc_device_t *abstract = (dc_device_t *) device;
+	dc_status_t rc = DC_STATUS_SUCCESS;
+
+	// Erase the buffer.
+	if (!dc_buffer_clear (buffer)) {
+		ERROR (abstract->context, "Insufficient buffer space available.");
+		return DC_STATUS_NOMEMORY;
+	}
+
+	// Transfer the request.
+	unsigned int n = 0;
+	unsigned char request[] = {0x22,
+		(id >> 8) & 0xFF,
+		(id     ) & 0xFF};
+	unsigned char response[SZ_PACKET];
+	rc = shearwater_common_transfer (device, request, sizeof (request), response, sizeof (response), &n);
+	if (rc != DC_STATUS_SUCCESS) {
+		return rc;
+	}
+
+	// Verify the response.
+	if (n < 3 || response[0] != 0x62 || response[1] != request[1] || response[2] != request[2]) {
+		ERROR (abstract->context, "Unexpected response packet.");
+		return DC_STATUS_PROTOCOL;
+	}
+
+	// Append the packet to the output buffer.
+	if (!dc_buffer_append (buffer, response + 3, n - 3)) {
+		ERROR (abstract->context, "Insufficient buffer space available.");
+		return DC_STATUS_NOMEMORY;
+	}
+
+	return rc;
+}

src/shearwater_common.h

@@ -29,6 +29,9 @@
 extern "C" {
 #endif /* __cplusplus */
 
+#define ID_SERIAL   0x8010
+#define ID_FIRMWARE 0x8011
+
 typedef struct shearwater_common_device_t {
 	dc_device_t base;
 	serial_t *port;
@@ -46,6 +49,9 @@ shearwater_common_transfer (shearwater_common_device_t *device, const unsigned c
 dc_status_t
 shearwater_common_download (shearwater_common_device_t *device, dc_buffer_t *buffer, unsigned int address, unsigned int size, unsigned int compression);
 
+dc_status_t
+shearwater_common_identifier (shearwater_common_device_t *device, dc_buffer_t *buffer, unsigned int id);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */

src/shearwater_petrel.c

@@ -61,6 +61,21 @@ static const dc_device_vtable_t shearwater_petrel_device_vtable = {
 };
 
 
+static unsigned int
+str2num (unsigned char data[], unsigned int size, unsigned int offset)
+{
+	unsigned int value = 0;
+	for (unsigned int i = offset; i < size; ++i) {
+		if (data[i] < '0' || data[i] > '9')
+			break;
+		value *= 10;
+		value += data[i] - '0';
+	}
+
+	return value;
+}
+
+
 dc_status_t
 shearwater_petrel_device_open (dc_device_t **out, dc_context_t *context, const char *name)
 {
@@ -148,6 +163,45 @@ shearwater_petrel_device_foreach (dc_device_t *abstract, dc_dive_callback_t call
 		return DC_STATUS_NOMEMORY;
 	}
 
+	// Read the serial number.
+	rc = shearwater_common_identifier (&device->base, buffer, ID_SERIAL);
+	if (rc != DC_STATUS_SUCCESS) {
+		ERROR (abstract->context, "Failed to read the serial number.");
+		dc_buffer_free (buffer);
+		dc_buffer_free (manifests);
+		return rc;
+	}
+
+	// Convert to a number.
+	unsigned char serial[4] = {0};
+	if (array_convert_hex2bin (dc_buffer_get_data (buffer), dc_buffer_get_size (buffer),
+		serial, sizeof (serial)) != 0 ) {
+		ERROR (abstract->context, "Failed to convert the serial number.");
+		dc_buffer_free (buffer);
+		dc_buffer_free (manifests);
+		return DC_STATUS_DATAFORMAT;
+
+	}
+
+	// Read the firmware version.
+	rc = shearwater_common_identifier (&device->base, buffer, ID_FIRMWARE);
+	if (rc != DC_STATUS_SUCCESS) {
+		ERROR (abstract->context, "Failed to read the firmware version.");
+		dc_buffer_free (buffer);
+		dc_buffer_free (manifests);
+		return rc;
+	}
+
+	// Convert to a number.
+	unsigned int firmware = str2num (dc_buffer_get_data (buffer), dc_buffer_get_size (buffer), 1);
+
+	// Emit a device info event.
+	dc_event_devinfo_t devinfo;
+	devinfo.model = 3;
+	devinfo.firmware = firmware;
+	devinfo.serial = array_uint32_be (serial);
+	device_event_emit (abstract, DC_EVENT_DEVINFO, &devinfo);
+
 	while (1) {
 		// Download a manifest.
 		rc = shearwater_common_download (&device->base, buffer, MANIFEST_ADDR, MANIFEST_SIZE, 0);