First implementation of native Uemis downloader

This includes one major hack that uses a private data structure from
libdivecomputer to allow us to show the Uemis Zurich as one computer the
user can import from.

Once the user has chosen the Uemis we don't use libdivecomputer but our
own downloader. Just like in the libdicecomputer case this runs in its own
thread and updates the import dialog with progress information.

The code also keeps track of the last dive that has been downloaded from a
Uemis computer so we only import new dives on subsequent downloads. And
since the Uemis Zurich gives us its device id, we make this a "per
divecomputer" property for people who dive with multiple Uemis Zurich
computers.

This uses the debugfile infrastructure to allow easily collecting
debugging output - especially on Windows where by default console output
is lost.

Known limitations: when the Uemis runs out of space (it uses its
filesystem for communication with the host computer) we have no graceful
way to reset things. This is why the code doesn't try to download ALL
dives on the computer but instead download them in increments of ten
dives. This clearly needs to be addressed once I understand how to reset
the device.

The Cancel button of the import dialog isn't correctly hooked up, yet.
I still need to figure out how to gracefully shut down a download without
potentially hanging the device.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

1 files changed, 597 insertions, 0 deletions

diff --git a/uemis-downloader.c b/uemis-downloader.c
new file mode 100644
index 000000000..89ffb8e91
--- /dev/null
+++ b/uemis-downloader.c
@@ -0,0 +1,597 @@
+/*
+ * uemis-downloader.c
+ *
+ * Copyright (c) Dirk Hohndel <dirk@hohndel.org>
+ * released under GPL2
+ *
+ * very (VERY) loosely based on the algorithms found in Java code by Fabian Gast <fgast@only640k.net>
+ * which was released under the BSD-STYLE BEER WARE LICENSE
+ * I believe that I only used the information about HOW to do this (download data from the Uemis
+ * Zurich) but did not actually use any of his copyrighted code, therefore the license under which
+ * he released his code does not apply to this new implementation in C
+ */
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <pthread.h>
+#include <unistd.h>
+#include <string.h>
+#include "uemis.h"
+#include "dive.h"
+#include "divelist.h"
+#include "display.h"
+#include "display-gtk.h"
+
+#define BUFLEN 2048
+#define NUM_PARAM_BUFS 6
+static char *param_buff[NUM_PARAM_BUFS];
+static char *reqtxt_path;
+static int reqtxt_file;
+static int filenr;
+static int number_of_files;
+static char *mbuf = NULL;
+static int mbuf_size = 0;
+
+struct argument_block {
+	const char *mountpath;
+	char **max_dive_data;
+	char **xml_buffer;
+	progressbar_t *progress;
+};
+
+static int import_thread_done = 0, import_thread_cancelled;
+static const char *progress_bar_text = "";
+static double progress_bar_fraction = 0.0;
+
+static GError *error(const char *fmt, ...)
+{
+	va_list args;
+	GError *error;
+
+	va_start(args, fmt);
+	error = g_error_new_valist(
+		g_quark_from_string("subsurface"),
+		DIVE_ERROR_PARSE, fmt, args);
+	va_end(args);
+	return error;
+}
+
+/* send text to the importer progress bar */
+static void uemis_info(const char *fmt, ...)
+{
+	static char buffer[32];
+	va_list ap;
+
+	va_start(ap, fmt);
+	vsnprintf(buffer, sizeof(buffer), fmt, ap);
+	va_end(ap);
+	progress_bar_text = buffer;
+}
+
+static long bytes_available(int file)
+{
+	long result;
+	long now = lseek(file, 0, SEEK_CUR);
+	result = lseek(file, 0, SEEK_END);
+	lseek(file, now, SEEK_SET);
+	return result;
+}
+
+static int number_of_file(char *path)
+{
+	int count = 0;
+	GDir *dir = g_dir_open(path, 0, NULL);
+	while (g_dir_read_name(dir))
+		count++;
+	return count;
+}
+
+/* Check if there's a req.txt file and get the starting filenr from it.
+ * Test for the maximum number of ANS files (I believe this is always
+ * 4000 but in case there are differences depending on firmware, this
+ * code is easy enough */
+static gboolean uemis_init(const char *path)
+{
+	char *ans_path;
+	int i;
+
+	if (!path)
+		return FALSE;
+	/* let's check if this is indeed a Uemis DC */
+	reqtxt_path = g_build_filename(path, "/req.txt", NULL);
+	reqtxt_file = g_open(reqtxt_path, O_RDONLY, 0666);
+	if (!reqtxt_file)
+		return FALSE;
+	if (bytes_available(reqtxt_file) > 5) {
+		char tmp[6];
+		read(reqtxt_file, tmp, 5);
+		tmp[5] = '\0';
+#if UEMIS_DEBUG > 2
+		fprintf(debugfile, "::r req.txt \"%s\"\n", tmp);
+#endif
+		if (sscanf(tmp + 1, "%d", &filenr) != 1)
+			return FALSE;
+	}
+#if UEMIS_DEBUG > 2
+	else {
+		fprintf(debugfile, "::r req.txt skipped as there were fewer than 5 bytes\n");
+	}
+#endif
+	close (reqtxt_file);
+
+	/* It would be nice if we could simply go back to the first set of
+	 * ANS files. Something like the below - unfortunately this is known
+	 * to fail - more information from Uemis is needed here.
+	 * Without code like this it is very easy when downloading large amounts
+	 * of dives to run out of space on the dive computer - which can only
+	 * be fixed by unmounting and rebooting the DC
+	 *	reqtxt_file = g_open(reqtxt_path, O_RDWR | O_CREAT | O_TRUNC, 0666);
+	 *	write(reqtxt_file, "n0001", 5);
+	 *	close(reqtxt_file);
+	 *	filenr = 1;
+	 */
+	ans_path = g_build_filename(path, "ANS", NULL);
+	number_of_files = number_of_file(ans_path);
+	g_free(ans_path);
+	/* initialize the array in which we collect the answers */
+	for (i = 0; i < NUM_PARAM_BUFS; i++)
+		param_buff[i] = "";
+	return TRUE;
+}
+
+static void str_append_with_delim(char *s, char *t)
+{
+	int len = strlen(s);
+	snprintf(s + len, BUFLEN - len, "%s{", t);
+}
+
+/* The communication protocoll with the DC is truly funky.
+ * After you write your request to the req.txt file you call this function.
+ * It writes the number of the next ANS file at the beginning of the req.txt
+ * file (prefixed by 'n' or 'r') and then again at the very end of it, after
+ * the full request (this time without the prefix).
+ * Then it syncs (not needed on Windows) and closes the file. */
+static void trigger_response(int file, char *command, int nr, long tailpos)
+{
+	char fl[10];
+
+	snprintf(fl, 8, "%s%04d", command, nr);
+#if UEMIS_DEBUG > 2
+	fprintf(debugfile,"::: %s (after seeks)\n", fl);
+#endif
+	lseek(file, 0, SEEK_SET);
+	write(file, fl, strlen(fl));
+	lseek(file, tailpos, SEEK_SET);
+	write(file, fl + 1, strlen(fl + 1));
+#ifndef WIN32
+	fsync(file);
+#endif
+	close(file);
+}
+
+static char *next_token(char **buf)
+{
+	char *q, *p = strchr(*buf, '{');
+	*p = '\0';
+	q = *buf;
+	*buf = p + 1;
+	return q;
+}
+
+/* poor man's tokenizer that understands a quoted delimter ('{') */
+static char *next_segment(char *buf, int *offset, int size)
+{
+	int i = *offset;
+	int seg_size;
+	gboolean done = FALSE;
+	char *segment;
+
+	while (!done) {
+		if (i < size) {
+			if (buf[i] == '\\' && i < size - 1 &&
+				(buf[i+1] == '\\' || buf[i+1] == '{'))
+				memcpy(buf + i, buf + i + 1, size - i - 1);
+			else if (buf[i] == '{')
+				done = TRUE;
+			i++;
+		} else {
+			done = TRUE;
+		}
+	}
+	seg_size = i - *offset - 1;
+	if (seg_size < 0)
+		seg_size = 0;
+	segment = malloc(seg_size + 1);
+	memcpy(segment, buf + *offset, seg_size);
+	segment[seg_size] = '\0';
+	*offset = i;
+	return segment;
+}
+
+/* a dynamically growing buffer to store the potentially massive responses.
+ * The binary data block can be more than 100k in size (base64 encoded) */
+static void mbuf_add(char *buf)
+{
+	if (buf) {
+		if (!mbuf) {
+			mbuf = strdup(buf);
+			mbuf_size = strlen(mbuf) + 1;
+		} else {
+			mbuf_size += strlen(buf);
+			mbuf = realloc(mbuf, mbuf_size);
+			strcat(mbuf, buf);
+		}
+#if UEMIS_DEBUG > 5
+		fprintf(debugfile,"added \"%s\" to mbuf - new length %d\n", buf, mbuf_size);
+#endif
+	}
+}
+
+/* are there more ANS files we can check? */
+static gboolean next_file(int max)
+{
+	if (filenr >= max)
+		return FALSE;
+	filenr++;
+	return TRUE;
+}
+
+/* ultra-simplistic; it doesn't deal with the case when the object_id is
+ * split across two chunks. It also doesn't deal with the discrepancy between
+ * object_id and dive number as understood by the dive computer */
+static void show_progress(char *buf)
+{
+	char *object;
+	object = strstr(buf, "object_id");
+	if (object) {
+		/* let the user know which dive we are working on */
+		char tmp[10];
+		char *p = object + 14;
+		char *t = tmp;
+
+		if (p < buf + strlen(buf)) {
+			while (*p != '{' && t < tmp + 9)
+				*t++ = *p++;
+			*t = '\0';
+			uemis_info("Reading dive %s", tmp);
+		}
+	}
+}
+
+/* send a request to the dive computer and collect the answer */
+static gboolean uemis_get_answer(const char *path, char *request, int n_param_in,
+			int n_param_out, char **error_text)
+{
+	int i = 0, file_length;
+	char sb[BUFLEN];
+	char fl[13];
+	char tmp[100];
+	gboolean searching = TRUE;
+	gboolean assembling_mbuf = FALSE;
+	gboolean ismulti = FALSE;
+	gboolean found_answer = FALSE;
+	gboolean more_files = TRUE;
+	gboolean answer_in_mbuf = FALSE;
+	char *ans_path;
+	int ans_file;
+
+	reqtxt_file = g_open(reqtxt_path, O_RDWR | O_CREAT, 0666);
+	snprintf(sb, BUFLEN, "n%04d12345678", filenr);
+	str_append_with_delim(sb, request);
+	for (i = 0; i < n_param_in; i++)
+		str_append_with_delim(sb, param_buff[i]);
+	if (! strcmp(request, "getDivelogs") || ! strcmp(request, "getDeviceData")) {
+		answer_in_mbuf = TRUE;
+		str_append_with_delim(sb, "");
+	}
+	str_append_with_delim(sb, "");
+	file_length = strlen(sb);
+	snprintf(fl, 10, "%08d", file_length - 13);
+	memcpy(sb + 5, fl, strlen(fl));
+#ifdef UEMIS_DEBUG
+	fprintf(debugfile,"::w req.txt \"%s\"\n", sb);
+#endif
+	if (write(reqtxt_file, sb, strlen(sb)) != strlen(sb)) {
+		*error_text = "short write to req.txt file";
+		return FALSE;
+	}
+	if (! next_file(number_of_files)) {
+		*error_text = "out of files";
+		more_files = FALSE;
+	}
+	trigger_response(reqtxt_file, "n", filenr, file_length);
+	usleep(100000);
+	mbuf = NULL;
+	mbuf_size = 0;
+	while (searching || assembling_mbuf) {
+		progress_bar_fraction = filenr / 4000.0;
+		snprintf(fl, 13, "ANS%d.TXT", filenr - 1);
+		ans_path = g_build_filename(path, "ANS", fl, NULL);
+		ans_file = g_open(ans_path, O_RDONLY, 0666);
+		read(ans_file, tmp, 100);
+		close(ans_file);
+#if UEMIS_DEBUG > 3
+		fprintf(debugfile, "::t %s \"%s\"\n", ans_path, tmp);
+#endif
+		g_free(ans_path);
+		if (tmp[0] == '1') {
+			searching = FALSE;
+			if (tmp[1] == 'm') {
+				assembling_mbuf = TRUE;
+				ismulti = TRUE;
+			}
+			if (tmp[2] == 'e')
+				assembling_mbuf = FALSE;
+			if (assembling_mbuf) {
+				if (! next_file(number_of_files)) {
+					*error_text = "Out of files";
+					more_files = FALSE;
+					assembling_mbuf = FALSE;
+				}
+				reqtxt_file = g_open(reqtxt_path, O_RDWR | O_CREAT, 0666);
+				trigger_response(reqtxt_file, "n", filenr, file_length);
+			}
+		} else {
+			if (! next_file(number_of_files - 1)) {
+				*error_text = "Out of files";
+				more_files = FALSE;
+				assembling_mbuf = FALSE;
+				searching = FALSE;
+			}
+			reqtxt_file = g_open(reqtxt_path, O_RDWR | O_CREAT, 0666);
+			trigger_response(reqtxt_file, "r", filenr, file_length);
+			usleep(100000);
+		}
+		if (ismulti && more_files && tmp[0] == '1') {
+			int size;
+			snprintf(fl, 13, "ANS%d.TXT", assembling_mbuf ? filenr - 2 : filenr - 1);
+			ans_path = g_build_filename(path, "ANS", fl, NULL);
+			ans_file = g_open(ans_path, O_RDONLY, 0666);
+			size = bytes_available(ans_file);
+			if (size > 3) {
+				char *buf = malloc(size - 2);
+				lseek(ans_file, 3, SEEK_CUR);
+				read(ans_file, buf, size - 3);
+				buf[size -3 ] = '\0';
+				mbuf_add(buf);
+				show_progress(buf);
+				free(buf);
+			}
+			close(ans_file);
+			usleep(100000);
+		}
+	}
+	if (more_files) {
+		int size = 0, j = 0;
+		char *buf = NULL;
+
+		if (!ismulti) {
+			snprintf(fl, 13, "ANS%d.TXT", filenr - 1);
+			ans_path = g_build_filename(path, "ANS", fl, NULL);
+			ans_file = g_open(ans_path, O_RDONLY, 0666);
+			size = bytes_available(ans_file);
+			if (size > 3) {
+				buf = malloc(size - 2);
+				lseek(ans_file, 3, SEEK_CUR);
+				read(ans_file, buf, size - 3);
+				buf[size - 3] = '\0';
+#if UEMIS_DEBUG > 2
+				fprintf(debugfile, "::r %s \"%s\"\n", ans_path, buf);
+#endif
+			}
+			close(ans_file);
+			free(ans_path);
+		} else {
+			ismulti = FALSE;
+		}
+#if UEMIS_DEBUG > 1
+		fprintf(debugfile,":r: %s\n", buf);
+#endif
+		if (!answer_in_mbuf)
+			for (i = 0; i < n_param_out && j < size; i++)
+				param_buff[i] = next_segment(buf, &j, size);
+		found_answer = TRUE;
+	}
+#if UEMIS_DEBUG
+	for (i = 0; i < n_param_out; i++)
+		fprintf(debugfile,"::: %d: %s\n", i, paarm_buff[i]);
+#endif
+	return found_answer;
+}
+
+/* Turn what we get from the dive computer into something
+ * that we can pass to the parse_xml function.
+ * The last 'object_id' that we see is returned as our current
+ * approximation of a last dive number */
+static char *process_raw_buffer(char *inbuf, char **max_divenr)
+{
+	/* we'll just reuse the mbuf infrastructure to assemble the xml buffer */
+	char *buf = strdup(inbuf);
+	char *tp, *bp, *tag, *type, *val;
+	gboolean done = FALSE;
+	int inbuflen = strlen(inbuf);
+	char *endptr = buf + inbuflen;
+
+	mbuf = NULL;
+	mbuf_size = 0;
+	mbuf_add("<dives type='uemis'><string></string>\n<list>\n");
+	bp = buf + 1;
+	tp = next_token(&bp);
+	if (strcmp(tp,"divelog") != 0)
+		return NULL;
+	tp = next_token(&bp);
+	if (strcmp(tp,"1.0") != 0)
+		return NULL;
+	mbuf_add("<dive type=\"uemis\" ref=\"divelog\" version=\"1.0\">\n");
+	while (!done) {
+		char *tmp;
+		int tmp_size;
+		tag = next_token(&bp);
+		type = next_token(&bp);
+		val = next_token(&bp);
+		if (! strcmp(tag, "object_id")) {
+			free(*max_divenr);
+			*max_divenr = strdup(val);
+		}
+		if (! strcmp(tag, "file_content")) {
+			tmp_size = 44 + strlen(tag) + strlen(val);
+			done = TRUE;
+		} else {
+			tmp_size = 27 + strlen(tag) + 2 * strlen(type) + strlen(val);
+		}
+		tmp = malloc(tmp_size);
+		snprintf(tmp, tmp_size,"<val key=\"%s\">\n<%s>%s</%s>\n</val>\n",
+			tag, type, val, type);
+		mbuf_add(tmp);
+		free(tmp);
+		/* done with one dive (got the file_content tag), but there could be more */
+		if (done && ++bp < endptr && *bp != '{') {
+			done = FALSE;
+			mbuf_add("</dive>\n");
+			mbuf_add("<dive type=\"uemis\" ref=\"divelog\" version=\"1.0\">\n");
+		}
+	}
+	mbuf_add("</dive>\n</list></dives>");
+	free(buf);
+	return strdup(mbuf);
+}
+
+/* to keep track of multiple computers we simply encode the last dive read
+   in tuples "{deviceid,nr},{deviceid,nr}..." no spaces to make parsing easier */
+
+static char *find_deviceid(char *max_dive_data, char *deviceid)
+{
+	char *pattern;
+	char *result;
+	if (! deviceid || *deviceid == '\0')
+		return NULL;
+	pattern = malloc(3 + strlen(deviceid));
+	sprintf(pattern, "{%s,", deviceid);
+	result = strstr(max_dive_data, pattern);
+	free(pattern);
+	return result;
+}
+
+static char *get_divenr(char *max_dive_data, char *deviceid)
+{
+	char *q, *p = max_dive_data;
+	char *result = "0";
+
+	if (!p || !deviceid)
+		return result;
+	p = find_deviceid(max_dive_data, deviceid);
+	if (p) {
+		p += strlen(deviceid) + 2;
+		q = strchr(p, '}');
+		if (!q)
+			return result;
+		result = malloc(q - p + 1);
+		strncpy(result, p, q - p);
+		result[q - p] = '\0';
+	}
+	return result;
+}
+
+static char *update_max_dive_data(char *max_dive_data, char *deviceid, char *newmax)
+{
+	char *p;
+	char *result;
+	int len;
+
+	if (! newmax || *newmax == '\0')
+		return max_dive_data;
+	p = find_deviceid(max_dive_data, deviceid);
+	if (p) {
+		/* if there are more entries after this one, copy them,
+		   otherwise just remove the existing entry for this device */
+		char *q = strstr(p, "},{");
+		if (q) {
+			memcpy(p + 1, q + 3, strlen(q + 3) + 1);
+		} else {
+			if (p > max_dive_data)
+				*(p-1) = '\0';
+			else
+				*p = '\0';
+		}
+	}
+	/* now add the new one at the end */
+	len = strlen(max_dive_data) + strlen(deviceid) + strlen(newmax) + 4 + (strlen(max_dive_data) ? 1 : 0);
+	result = malloc(len);
+	snprintf(result, len, "%s%s{%s,%s}", max_dive_data, strlen(max_dive_data) ? "," : "", deviceid, newmax);
+	free(max_dive_data);
+	return result;
+}
+
+static char *do_uemis_download(struct argument_block *args)
+{
+	const char *mountpath = args->mountpath;
+	char **max_dive_data = args->max_dive_data;
+	char **xml_buffer = args->xml_buffer;
+	char *error_text = "";
+	char *newmax = NULL;
+	char *deviceid;
+
+	*xml_buffer = NULL;
+	uemis_info("Init Communication");
+	if (! uemis_init(mountpath))
+		return "Uemis init failed";
+	if (! uemis_get_answer(mountpath, "getDeviceId", 0, 1, &error_text))
+		return error_text;
+	deviceid = strdup(param_buff[0]);
+	/* the answer from the DeviceId call becomes the input parameter for getDeviceData */
+	if (! uemis_get_answer(mountpath, "getDeviceData", 1, 0, &error_text))
+		return error_text;
+	/* param_buff[0] is still valid */
+	if (! uemis_get_answer(mountpath, "initSession", 1, 6, &error_text))
+		return error_text;
+	uemis_info("Start download");
+	if (! uemis_get_answer(mountpath, "processSync", 0, 2, &error_text))
+		return error_text;
+	param_buff[1] = "notempty";
+	param_buff[2] = get_divenr(*max_dive_data, deviceid);
+	if (uemis_get_answer(mountpath, "getDivelogs", 3, 0, &error_text)) {
+		if (mbuf)
+			*xml_buffer = process_raw_buffer(mbuf, &newmax);
+	} else {
+		return error_text;
+	}
+	*args->max_dive_data = update_max_dive_data(*max_dive_data, deviceid, newmax);
+	free(newmax);
+	if (! uemis_get_answer(mountpath, "terminateSync", 0, 1, &error_text))
+		return error_text;
+
+	return NULL;
+}
+
+static void *pthread_wrapper(void *_data)
+{
+	struct argument_block *args = _data;
+	const char *err_string = do_uemis_download(args);
+	import_thread_done = 1;
+	return (void *)err_string;
+}
+
+GError *uemis_download(const char *mountpath, char **max_dive_data, char **xml_buffer, progressbar_t *progress)
+{
+	pthread_t pthread;
+	void *retval;
+	struct argument_block args = {mountpath, max_dive_data, xml_buffer, progress};
+
+	/* I'm sure there is some better interface for waiting on a thread in a UI main loop */
+	import_thread_done = 0;
+	progress_bar_text = "";
+	progress_bar_fraction = 0.0;
+	pthread_create(&pthread, NULL, pthread_wrapper, &args);
+	while (!import_thread_done) {
+		import_thread_cancelled = process_ui_events();
+		update_progressbar(args.progress, progress_bar_fraction);
+		update_progressbar_text(args.progress, progress_bar_text);
+		usleep(100000);
+	}
+	if (pthread_join(pthread, &retval) < 0)
+		return error("Pthread return with error");
+	if (retval)
+		return error(retval);
+	return NULL;
+}