2 files changed, 70 insertions, 2 deletions

diff --git a/src/errors.c b/src/errors.c
index 58e0976f2..0105c2538 100644
--- a/src/errors.c
+++ b/src/errors.c
@@ -6,6 +6,7 @@
  */
 #include "common.h"
 #include "global.h"
+#include "posix.h"
 #include <stdarg.h>
 
 static struct {
@@ -102,3 +103,66 @@ void git_clearerror(void)
 	char *last_error = GIT_GLOBAL->error.last;
 	last_error[0] = '\0';
 }
+
+/********************************************
+ * New error handling
+ ********************************************/
+
+void giterr_set(git_error **error_out, int error_class, const char *string, ...)
+{
+	char error_str[1024];
+	va_list arglist;
+	git_error *error;
+
+	if (error_out == NULL)
+		return;
+
+	error = git__malloc(sizeof(git_error));
+	if (!error) {
+		giterr_set_oom(error_out);
+		return;
+	}
+
+	va_start(arglist, string);
+	p_vsnprintf(error_str, sizeof(error_str), string, arglist);
+	va_end(arglist);
+
+	error->message = git__strdup(error_str);
+	error->klass = error_class;
+
+	if (error->message == NULL) {
+		free(error);
+		giterr_set_oom(error_out);
+		return;
+	}
+
+	*error_out = error;
+}
+
+static git_error g_git_oom_error = {
+	"Out of memory",
+	GITERR_NOMEMORY
+};
+
+void giterr_set_oom(git_error **error)
+{
+	if (error != NULL)
+		*error = &g_git_oom_error;
+}
+
+void giterr_free(git_error *error)
+{
+	if (error == NULL || error == &g_git_oom_error)
+		return;
+
+	free(error->message);
+	free(error);
+}
+
+void giterr_clear(git_error **error)
+{
+	if (error != NULL) {
+		giterr_free(*error);
+		*error = NULL;
+	}
+}
diff --git a/src/win32/posix_w32.c b/src/win32/posix_w32.c
index 91585aeae..8e70719f9 100644
--- a/src/win32/posix_w32.c
+++ b/src/win32/posix_w32.c
@@ -341,8 +341,12 @@ done:
 int p_vsnprintf(char *buffer, size_t count, const char *format, va_list argptr)
 {
 #ifdef _MSC_VER
-	int len = _vsnprintf(buffer, count, format, argptr);
-	return (len < 0) ? _vscprintf(format, argptr) : len;
+	int len;
+
+	if (count == 0 || (len = _vsnprintf(buffer, count, format, argptr)) < 0)
+		return p_vscprintf(format, argptr);
+
+	return len;
 #else /* MinGW */
 	return vsnprintf(buffer, count, format, argptr);
 #endif