From d4f2b7214863b2a40ebcf69e7add113412f795b8 Mon Sep 17 00:00:00 2001
From: Dirk Hohndel <dirk@hohndel.org>
Date: Thu, 12 Feb 2015 23:35:52 -0800
Subject: [PATCH] Make special backup when switching XML versions

Since the last few dozen commits change the format in irreversible ways
and could therefore be destructive and lose data for testers of the
development version, let's try to be extra careful and create "special"
backup files that aren't overwritten by subsequent backups. At least this
way people can go back to the previous state.

Of course people using the git backend don't have to worry about this as
they always can go back to any earlier save.

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>
---
 dive.h      |  2 ++
 parse-xml.c |  4 ++++
 save-xml.c  | 10 +++++++++-
 3 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/dive.h b/dive.h
index 09c831e43..9de3423ad 100644
--- a/dive.h
+++ b/dive.h
@@ -48,6 +48,8 @@ extern "C" {
 #include <stdbool.h>
 #endif
 
+extern int last_xml_version;
+
 enum dive_comp_type {OC, CCR, PSCR, FREEDIVE, NUM_DC_TYPE};	// Flags (Open-circuit and Closed-circuit-rebreather) for setting dive computer type
 enum cylinderuse {OC_GAS, DILUENT, OXYGEN, NUM_GAS_USE}; // The different uses for cylinders
 
diff --git a/parse-xml.c b/parse-xml.c
index c93d25453..6cc2d881a 100644
--- a/parse-xml.c
+++ b/parse-xml.c
@@ -21,6 +21,7 @@
 
 int verbose, quit;
 int metric = 1;
+int last_xml_version = -1;
 
 static xmlDoc *test_xslt_transforms(xmlDoc *doc, const char **params);
 
@@ -1644,6 +1645,9 @@ static void userid_stop(void)
 
 static void entry(const char *name, char *buf)
 {
+	if (!strncmp(name, "version.program", sizeof("version.program") - 1) ||
+	    !strncmp(name, "version.divelog", sizeof("version.divelog") - 1))
+		last_xml_version = atoi(buf);
 	if (in_userid) {
 		try_to_fill_userid(name, buf);
 		return;
diff --git a/save-xml.c b/save-xml.c
index dad57dc9b..5a0c6976c 100644
--- a/save-xml.c
+++ b/save-xml.c
@@ -591,7 +591,15 @@ static void try_to_backup(const char *filename)
 	while (extension[i][0] != '\0') {
 		int elen = strlen(extension[i]);
 		if (strcasecmp(filename + flen - elen, extension[i]) == 0) {
-			save_backup(filename, extension[i], "bak");
+			if (last_xml_version < VERSION) {
+				int se_len = strlen(extension[i]) + 5;
+				char *special_ext = malloc(se_len);
+				snprintf(special_ext, se_len, "%s.v%d", extension[i], last_xml_version);
+				save_backup(filename, extension[i], special_ext);
+				free(special_ext);
+			} else {
+				save_backup(filename, extension[i], "bak");
+			}
 			break;
 		}
 		i++;