1 files changed, 58 insertions, 0 deletions
diff --git a/src/core/lib/iomgr/error.c b/src/core/lib/iomgr/error.c
index e366961936..31c80260f8 100644
--- a/src/core/lib/iomgr/error.c
+++ b/src/core/lib/iomgr/error.c
@@ -324,6 +324,64 @@ const char *grpc_error_get_str(grpc_error *err, grpc_error_strs which) {
   return gpr_avl_get(err->strs, (void *)(uintptr_t)which);
 }
 
+typedef struct {
+  grpc_error *error;
+  grpc_status_code code;
+  const char *msg;
+} special_error_status_map;
+static special_error_status_map error_status_map[] = {
+    {GRPC_ERROR_NONE, GRPC_STATUS_OK, ""},
+    {GRPC_ERROR_CANCELLED, GRPC_STATUS_CANCELLED, "RPC cancelled"},
+    {GRPC_ERROR_OOM, GRPC_STATUS_RESOURCE_EXHAUSTED, "Out of memory"},
+};
+
+static grpc_error *recursively_find_error_with_status(grpc_error *error,
+                                                      intptr_t *status) {
+  // If the error itself has a status code, return it.
+  if (grpc_error_get_int(error, GRPC_ERROR_INT_GRPC_STATUS, status)) {
+    return error;
+  }
+  // Otherwise, search through its children.
+  intptr_t key = 0;
+  while (true) {
+    grpc_error *child_error = gpr_avl_get(error->errs, (void *)key++);
+    if (child_error == NULL) break;
+    grpc_error *result =
+        recursively_find_error_with_status(child_error, status);
+    if (result != NULL) return result;
+  }
+  return NULL;
+}
+
+void grpc_error_get_status(grpc_error *error, grpc_status_code *code,
+                           const char **msg) {
+  // Handle special errors via the static map.
+  for (size_t i = 0; i < GPR_ARRAY_SIZE(error_status_map); ++i) {
+    if (error == error_status_map[i].error) {
+      *code = error_status_map[i].code;
+      *msg = error_status_map[i].msg;
+      return;
+    }
+  }
+  // Populate code.
+  // Start with the parent error and recurse through the tree of children
+  // until we find the first one that has a status code.
+  intptr_t status = GRPC_STATUS_UNKNOWN;  // Default in case we don't find one.
+  grpc_error *found_error = recursively_find_error_with_status(error, &status);
+  *code = (grpc_status_code)status;
+  // Now populate msg.
+  // If we found an error with a status code above, use that; otherwise,
+  // fall back to using the parent error.
+  if (found_error == NULL) found_error = error;
+  // If the error has a status message, use it.  Otherwise, fall back to
+  // the error description.
+  *msg = grpc_error_get_str(found_error, GRPC_ERROR_STR_GRPC_MESSAGE);
+  if (*msg == NULL) {
+    *msg = grpc_error_get_str(found_error, GRPC_ERROR_STR_DESCRIPTION);
+    if (*msg == NULL) *msg = "uknown error";  // Just in case.
+  }
+}
+
 grpc_error *grpc_error_add_child(grpc_error *src, grpc_error *child) {
   GPR_TIMER_BEGIN("grpc_error_add_child", 0);
   grpc_error *new = copy_error_and_unref(src);