Fix default filename handling errors

The default filename handling is broken in two different ways:

 (a) if we start subsurface with a non-existing file, we warn about
the inability to read that file, and then we exit without setting the
default filename.

This is broken because it means that if the user (perhaps by mistake,
by pressing ^S) now saves the file, he will overwrite the default
filename, even though that was *not* the file we read, and *not* the
file that subsurface was started with.

So just set the default filename even for a failed file open.

The exact same logic is true of a failed parse of an XML file that we
successfully opened. We do *not* want to leave the old default
filename in place just because the XML parsing failed, and possibly
then overwriting some file that was never involved with that failure
in the first place. So just get rid of all the logic to push the
filename saving into the XML parsing layer, it has zero relevance at
that point.

 (b) if we do replace the default filename with a NULL file, we need
to set that even if we cannot do a strdup() on the NULL.

This fixes both errors.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

4 files changed, 20 insertions, 13 deletions

diff --git a/dive.h b/dive.h
index 949be20d3..d303c81b7 100644
--- a/dive.h
+++ b/dive.h
@@ -352,8 +352,7 @@ static inline struct dive *get_dive(int nr)
 	for ((_i) = 0; ((_x) = get_dive(_i)) != NULL; (_i)++)
 
 extern void parse_xml_init(void);
-extern void parse_xml_buffer(const char *url, const char *buf, int size, GError **error,
-			gboolean possible_default_filename);
+extern void parse_xml_buffer(const char *url, const char *buf, int size, GError **error);
 extern void parse_xml_exit(void);
 extern void set_filename(const char *filename, gboolean force);
 
diff --git a/file.c b/file.c
index 93abb8b9e..db72b5f66 100644
--- a/file.c
+++ b/file.c
@@ -72,7 +72,7 @@ static void suunto_read(struct zip_file *file, GError **error)
 		size = read * 3 / 2;
 		mem = realloc(mem, size);
 	}
-	parse_xml_buffer(_("SDE file"), mem, read, error, FALSE);
+	parse_xml_buffer(_("SDE file"), mem, read, error);
 	free(mem);
 }
 #endif
@@ -240,14 +240,13 @@ static int open_by_filename(const char *filename, const char *fmt, struct memblo
 	return 0;
 }
 
-static void parse_file_buffer(const char *filename, struct memblock *mem, GError **error,
-	gboolean possible_default_filename)
+static void parse_file_buffer(const char *filename, struct memblock *mem, GError **error)
 {
 	char *fmt = strrchr(filename, '.');
 	if (fmt && open_by_filename(filename, fmt+1, mem, error))
 		return;
 
-	parse_xml_buffer(filename, mem->buffer, mem->size, error, possible_default_filename);
+	parse_xml_buffer(filename, mem->buffer, mem->size, error);
 }
 
 void parse_file(const char *filename, GError **error, gboolean possible_default_filename)
@@ -266,9 +265,20 @@ void parse_file(const char *filename, GError **error, gboolean possible_default_
 					     _("Failed to read '%s'"),
 					     filename);
 		}
+
+		/*
+		 * We do *not* want to leave the old default_filename
+		 * just because the open failed.
+		 */
+		if (possible_default_filename)
+			set_filename(filename, TRUE);
+
 		return;
 	}
 
-	parse_file_buffer(filename, &mem, error, possible_default_filename);
+	if (possible_default_filename)
+		set_filename(filename, TRUE);
+
+	parse_file_buffer(filename, &mem, error);
 	free(mem.buffer);
 }
diff --git a/gtk-gui.c b/gtk-gui.c
index 690b2a488..0b297b753 100644
--- a/gtk-gui.c
+++ b/gtk-gui.c
@@ -1518,7 +1518,7 @@ static GError *setup_uemis_import(device_data_t *data)
 #ifdef DEBUGFILE
 		fprintf(debugfile, "xml buffer \"%s\"\n\n", buf);
 #endif
-		parse_xml_buffer("Uemis Download", buf, strlen(buf), &error, FALSE);
+		parse_xml_buffer("Uemis Download", buf, strlen(buf), &error);
 		set_uemis_last_dive(uemis_max_dive_data);
 #if UEMIS_DEBUG
 		fprintf(debugfile, "uemis_max_dive_data: %s\n", uemis_max_dive_data);
@@ -1672,4 +1672,6 @@ void set_filename(const char *filename, gboolean force)
 	free((void *)existing_filename);
 	if (filename)
 		existing_filename = strdup(filename);
+	else
+		existing_filename = NULL;
 }
diff --git a/parse-xml.c b/parse-xml.c
index 272b82c0f..b4fc9e716 100644
--- a/parse-xml.c
+++ b/parse-xml.c
@@ -1485,8 +1485,7 @@ static void reset_all(void)
 	import_source = UNKNOWN;
 }
 
-void parse_xml_buffer(const char *url, const char *buffer, int size, GError **error,
-		gboolean possible_default_filename)
+void parse_xml_buffer(const char *url, const char *buffer, int size, GError **error)
 {
 	xmlDoc *doc;
 
@@ -1502,9 +1501,6 @@ void parse_xml_buffer(const char *url, const char *buffer, int size, GError **er
 		}
 		return;
 	}
-	/* remember, if necessary, that this is the filename to store to */
-	if (possible_default_filename)
-		set_filename(url, FALSE);
 	reset_all();
 	dive_start();
 #ifdef XSLT