From 79babf18f63c0d533d67e69724308aa9598e4c35 Mon Sep 17 00:00:00 2001
From: Joe Shaw <jshaw@fastly.com>
Date: Thu, 13 Jun 2024 11:36:08 -0400
Subject: [PATCH] add adaptive buffer support for geo + device detection
 lookups

Write out the required buffer size to the nwritten_out value if the
buffer is too small to fit the value.
---
 lib/src/wiggle_abi/device_detection_impl.rs | 1 +
 lib/src/wiggle_abi/geo_impl.rs              | 1 +
 2 files changed, 2 insertions(+)

diff --git a/lib/src/wiggle_abi/device_detection_impl.rs b/lib/src/wiggle_abi/device_detection_impl.rs
index 5222829d..7fbf8aa7 100644
--- a/lib/src/wiggle_abi/device_detection_impl.rs
+++ b/lib/src/wiggle_abi/device_detection_impl.rs
@@ -44,6 +44,7 @@ impl FastlyDeviceDetection for Session {
         };
 
         if result.len() > buf_len as usize {
+            nwritten_out.write(buf_len)?;
             return Err(Error::BufferLengthError {
                 buf: "device_detection_lookup",
                 len: "device_detection_lookup_max_len",
diff --git a/lib/src/wiggle_abi/geo_impl.rs b/lib/src/wiggle_abi/geo_impl.rs
index 5f2e4b02..906dcf25 100644
--- a/lib/src/wiggle_abi/geo_impl.rs
+++ b/lib/src/wiggle_abi/geo_impl.rs
@@ -39,6 +39,7 @@ impl FastlyGeo for Session {
         let result = self.geolocation_lookup(&ip_addr).unwrap_or_default();
 
         if result.len() > buf_len as usize {
+            nwritten_out.write(buf_len)?;
             return Err(Error::BufferLengthError {
                 buf: "geolocation_lookup",
                 len: "geolocation_lookup_max_len",