Add an embryo of a TLS-aware error handling system

This adds the per-thread global variable git_errno to the
system, which callers can examine to get information about
an error.

Two helper functions are added to reduce LoC-count for the
library code itself.

Also, some exceptions are made for running sparse on GIT_TLS
definitions, since it doesn't grok thread-local variables at
all.

Signed-off-by: Andreas Ericsson <ae@op5.se>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 23 insertions, 0 deletions

diff --git a/src/errors.c b/src/errors.c
new file mode 100644
index 000000000..b3e014dd4
--- /dev/null
+++ b/src/errors.c
@@ -0,0 +1,23 @@
+#include "common.h"
+#include "thread-utils.h" /* for GIT_TLS */
+
+/* compile-time constant initialization required */
+GIT_TLS int git_errno = 0;
+
+static struct {
+	int num;
+	const char *str;
+} error_codes[] = {
+	{ GIT_ENOTOID, "Not a git oid" },
+	{ GIT_ENOTFOUND, "Object does not exist in the scope searched" },
+};
+
+const char *git_strerror(int num)
+{
+	int i;
+	for (i = 0; i < ARRAY_SIZE(error_codes); i++)
+		if (num == error_codes[i].num)
+			return error_codes[i].str;
+
+	return "Unknown error";
+}