Improve GIT_EUSER handling

This adds giterr_user_cancel to return GIT_EUSER and clear any
error message that is sitting around.  As a result of using that
in places, we need to be more thorough with capturing errors that
happen inside a callback when used internally.  To help with that,
this also adds giterr_capture and giterr_restore so that when we
internally use a foreach-type function that clears errors and
converts them to GIT_EUSER, it is easier to restore not just the
return value, but the actual error message text.

1 files changed, 42 insertions, 3 deletions

diff --git a/src/errors.c b/src/errors.c
index d04da4ca9..a0b085923 100644
--- a/src/errors.c
+++ b/src/errors.c
@@ -23,7 +23,8 @@ static void set_error(int error_class, char *string)
 {
 	git_error *error = &GIT_GLOBAL->error_t;
 
-	git__free(error->message);
+	if (error->message != string)
+		git__free(error->message);
 
 	error->message = string;
 	error->klass = error_class;
@@ -103,8 +104,10 @@ int giterr_set_regex(const regex_t *regex, int error_code)
 
 void giterr_clear(void)
 {
-	set_error(0, NULL);
-	GIT_GLOBAL->last_error = NULL;
+	if (GIT_GLOBAL->last_error != NULL) {
+		set_error(0, NULL);
+		GIT_GLOBAL->last_error = NULL;
+	}
 
 	errno = 0;
 #ifdef GIT_WIN32
@@ -134,3 +137,39 @@ const git_error *giterr_last(void)
 {
 	return GIT_GLOBAL->last_error;
 }
+
+int giterr_capture(git_error_state *state, int error_code)
+{
+	state->error_code = error_code;
+	if (error_code)
+		giterr_detach(&state->error_msg);
+	return error_code;
+}
+
+int giterr_restore(git_error_state *state)
+{
+	if (state && state->error_code && state->error_msg.message)
+		set_error(state->error_msg.klass, state->error_msg.message);
+	else
+		giterr_clear();
+
+	return state ? state->error_code : 0;
+}
+
+int giterr_system_last(void)
+{
+#ifdef GIT_WIN32
+	return GetLastError();
+#else
+	return errno;
+#endif
+}
+
+void giterr_system_set(int code)
+{
+#ifdef GIT_WIN32
+	SetLastError(code);
+#else
+	errno = code;
+#endif
+}