Make report_error() reentrant

Remove the global error buffer and pass the error string directly
to the frontend. The frontend is then responsible for accumulating
errors.

Signed-off-by: Berthold Stoeger <bstoeger@mail.tuwien.ac.at>

2 files changed, 10 insertions, 30 deletions

diff --git a/core/dive.h b/core/dive.h
index c155abbfd..3793cc359 100644
--- a/core/dive.h
+++ b/core/dive.h
@@ -719,7 +719,7 @@ extern "C" {
 
 extern int report_error(const char *fmt, ...);
 extern const char *get_error_string(void);
-extern void set_error_cb(void(*cb)(void));
+extern void set_error_cb(void(*cb)(char *));	// Callback takes ownership of passed string
 
 extern struct dive *find_dive_including(timestamp_t when);
 extern bool dive_within_time_range(struct dive *dive, timestamp_t when, timestamp_t offset);
diff --git a/core/errorhelper.c b/core/errorhelper.c
index 0f544efb6..5390c4c20 100644
--- a/core/errorhelper.c
+++ b/core/errorhelper.c
@@ -8,43 +8,23 @@
 
 #define VA_BUF(b, fmt) do { va_list args; va_start(args, fmt); put_vformat(b, fmt, args); va_end(args); } while (0)
 
-static struct membuffer error_string_buffer = { 0 };
-static void (*error_cb)(void) = NULL;
-/*
- * Note that the act of "getting" the error string
- * buffer doesn't de-allocate the buffer, but it does
- * set the buffer length to zero, so that any future
- * error reports will overwrite the string rather than
- * append to it.
- */
-const char *get_error_string(void)
-{
-	const char *str;
-
-	if (!error_string_buffer.len)
-		return "";
-	str = mb_cstring(&error_string_buffer);
-	error_string_buffer.len = 0;
-	return str;
-}
+static void (*error_cb)(char *) = NULL;
 
 int report_error(const char *fmt, ...)
 {
-	struct membuffer *buf = &error_string_buffer;
+	struct membuffer buf = { 0 };
 
-	/* Previous unprinted errors? Add a newline in between */
-	if (buf->len)
-		put_bytes(buf, "\n", 1);
-	VA_BUF(buf, fmt);
-	mb_cstring(buf);
+	/* if there is no error callback registered, don't produce errors */
+	if (!error_cb)
+		return -1;
 
-	/* if an error callback is registered, call it */
-	if (error_cb)
-		error_cb();
+	VA_BUF(&buf, fmt);
+	mb_cstring(&buf);
+	error_cb(detach_buffer(&buf));
 
 	return -1;
 }
 
-void set_error_cb(void(*cb)(void)) {
+void set_error_cb(void(*cb)(char *)) {
 	error_cb = cb;
 }