Much improved handling of out of memory errors in the Uemis downloader

Instead of trying to figure out in the GUI code whether to call the
downloader again, the logic was moved into the downloader itself. It now
attempts to deal cleverly with running out of space on the dive computer
filesystem - and in return is able to process the maximum number of dives
(instead of just ten or so at a time).

Even on partial reads before a failure we are able to collect the data
that was completely transferred and report those dives.

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

1 files changed, 48 insertions, 16 deletions

diff --git a/uemis-downloader.c b/uemis-downloader.c
index 89ffb8e91..b6bec16f5 100644
--- a/uemis-downloader.c
+++ b/uemis-downloader.c
@@ -23,6 +23,9 @@
 #include "display.h"
 #include "display-gtk.h"
 
+#define ERR_FS_ALMOST_FULL "Uemis Zurich: File System is almost full\nDisconnect/reconnect the dive computer\nand try again"
+#define ERR_FS_FULL "Uemis Zurich: File System is full\nDisconnect/reconnect the dive computer\nand try again"
+#define ERR_FS_SHORT_WRITE "Short write to req.txt file\nIs the Uemis Zurich plugged in correctly?"
 #define BUFLEN 2048
 #define NUM_PARAM_BUFS 6
 static char *param_buff[NUM_PARAM_BUFS];
@@ -173,7 +176,10 @@ static void trigger_response(int file, char *command, int nr, long tailpos)
 static char *next_token(char **buf)
 {
 	char *q, *p = strchr(*buf, '{');
-	*p = '\0';
+	if (p)
+		*p = '\0';
+	else
+		p = *buf + strlen(*buf) - 1;
 	q = *buf;
 	*buf = p + 1;
 	return q;
@@ -293,11 +299,11 @@ static gboolean uemis_get_answer(const char *path, char *request, int n_param_in
 	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";
+		*error_text = ERR_FS_SHORT_WRITE;
 		return FALSE;
 	}
 	if (! next_file(number_of_files)) {
-		*error_text = "out of files";
+		*error_text = ERR_FS_FULL;
 		more_files = FALSE;
 	}
 	trigger_response(reqtxt_file, "n", filenr, file_length);
@@ -325,7 +331,7 @@ static gboolean uemis_get_answer(const char *path, char *request, int n_param_in
 				assembling_mbuf = FALSE;
 			if (assembling_mbuf) {
 				if (! next_file(number_of_files)) {
-					*error_text = "Out of files";
+					*error_text = ERR_FS_FULL;
 					more_files = FALSE;
 					assembling_mbuf = FALSE;
 				}
@@ -334,7 +340,7 @@ static gboolean uemis_get_answer(const char *path, char *request, int n_param_in
 			}
 		} else {
 			if (! next_file(number_of_files - 1)) {
-				*error_text = "Out of files";
+				*error_text = ERR_FS_FULL;
 				more_files = FALSE;
 				assembling_mbuf = FALSE;
 				searching = FALSE;
@@ -445,8 +451,11 @@ static char *process_raw_buffer(char *inbuf, char **max_divenr)
 			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 with one dive (got the file_content tag), but there could be more:
+		 * a '{' indicates the end of the record - but we need to see another "{{"
+		 * later in the buffer to know that the next record is complete (it could
+		 * be a short read because of some error */
+		if (done && ++bp < endptr && *bp != '{' && strstr(bp, "{{")) {
 			done = FALSE;
 			mbuf_add("</dive>\n");
 			mbuf_add("<dive type=\"uemis\" ref=\"divelog\" version=\"1.0\">\n");
@@ -476,10 +485,10 @@ static char *find_deviceid(char *max_dive_data, char *deviceid)
 static char *get_divenr(char *max_dive_data, char *deviceid)
 {
 	char *q, *p = max_dive_data;
-	char *result = "0";
+	char *result = NULL;
 
 	if (!p || !deviceid)
-		return result;
+		return strdup("0");
 	p = find_deviceid(max_dive_data, deviceid);
 	if (p) {
 		p += strlen(deviceid) + 2;
@@ -490,6 +499,8 @@ static char *get_divenr(char *max_dive_data, char *deviceid)
 		strncpy(result, p, q - p);
 		result[q - p] = '\0';
 	}
+	if (!result)
+		result = strdup("0");
 	return result;
 }
 
@@ -531,6 +542,8 @@ static char *do_uemis_download(struct argument_block *args)
 	char *error_text = "";
 	char *newmax = NULL;
 	char *deviceid;
+	char *result = NULL;
+	gboolean success;
 
 	*xml_buffer = NULL;
 	uemis_info("Init Communication");
@@ -549,19 +562,38 @@ static char *do_uemis_download(struct argument_block *args)
 	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)) {
+	newmax = get_divenr(*max_dive_data, deviceid);
+	for (;;) {
+		param_buff[2] = newmax;
+		success = uemis_get_answer(mountpath, "getDivelogs", 3, 0, &error_text);
+		/* if we got a buffer back, try to process it */
 		if (mbuf)
 			*xml_buffer = process_raw_buffer(mbuf, &newmax);
-	} else {
-		return error_text;
+		/* if we got an error, deal with it */
+		if (!success) {
+			result = error_text;
+			break;
+		}
+		/* also, if we got nothing back, we should stop trying */
+		if (!mbuf)
+			break;
+		/* finally, if the memory is getting too full, maybe we better stop, too */
+		if (progress_bar_fraction > 0.85) {
+			result = ERR_FS_ALMOST_FULL;
+			break;
+		}
 	}
 	*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))
+	if (! uemis_get_answer(mountpath, "terminateSync", 0, 3, &error_text))
 		return error_text;
-
-	return NULL;
+	if (! strcmp(param_buff[0], "error")) {
+		if (! strcmp(param_buff[2],"Out of Memory"))
+			result = ERR_FS_FULL;
+		else
+			result = param_buff[2];
+	}
+	return result;
 }
 
 static void *pthread_wrapper(void *_data)