refactor(api): VALIDATE macros #22256

- VALIDATE() takes a format string
- deduplicate check_string_array
- VALIDATE_RANGE
- validate UI args

src/nvim/api/private/validate.c

@@ -0,0 +1,28 @@
+// This is an open source non-commercial project. Dear PVS-Studio, please check
+// it. PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com
+
+#include "nvim/api/private/defs.h"
+#include "nvim/api/private/helpers.h"
+#include "nvim/api/private/validate.h"
+
+#ifdef INCLUDE_GENERATED_DECLARATIONS
+# include "api/private/validate.c.generated.h"
+#endif
+
+bool check_string_array(Array arr, char *name, bool disallow_nl, Error *err)
+{
+  snprintf(IObuff, sizeof(IObuff), "'%s' item", name);
+  for (size_t i = 0; i < arr.size; i++) {
+    VALIDATE_T(IObuff, kObjectTypeString, arr.items[i].type, {
+      return false;
+    });
+    // Disallow newlines in the middle of the line.
+    if (disallow_nl) {
+      const String l = arr.items[i].data.string;
+      VALIDATE(!memchr(l.data, NL, l.size), "'%s' item contains newlines", name, {
+        return false;
+      });
+    }
+  }
+  return true;
+}