From 0d3b29b7b37e7a7a0cf0201494d974e0fe1f24de Mon Sep 17 00:00:00 2001
From: Qi <qiqi.zhang@konghq.com>
Date: Wed, 31 Jan 2024 16:24:52 +0800
Subject: [PATCH] perf(router): remove NYI to be more JIT-friendly

---
 changelog/unreleased/kong/speed_up_router.yml |   3 +
 kong/router/fields.lua                        | 103 ++++++++++--------
 2 files changed, 60 insertions(+), 46 deletions(-)
 create mode 100644 changelog/unreleased/kong/speed_up_router.yml

diff --git a/changelog/unreleased/kong/speed_up_router.yml b/changelog/unreleased/kong/speed_up_router.yml
new file mode 100644
index 000000000000..c6d1b5fab9ab
--- /dev/null
+++ b/changelog/unreleased/kong/speed_up_router.yml
@@ -0,0 +1,3 @@
+message: Speed up the router matching when the `router_flavor` is `traditional_compatible` or `expressions`.
+type: performance
+scope: Performance
diff --git a/kong/router/fields.lua b/kong/router/fields.lua
index 40dd85609f7f..d970e74b187a 100644
--- a/kong/router/fields.lua
+++ b/kong/router/fields.lua
@@ -261,56 +261,29 @@ if is_http then
     return params
   end
 
+  local function gen_http_headers_field_accessor(name)
+    return function(params)
+      if not params.headers then
+        params.headers = get_http_params(get_headers, "headers", "lua_max_req_headers")
+      end
 
-  get_field_accessor = function(funcs, field)
-    local f = FIELDS_FUNCS[field] or funcs[field]
-    if f then
-      return f
+      return params.headers[name]
     end
+  end
 
-    local prefix = field:sub(1, PREFIX_LEN)
-
-    -- generate for http.headers.*
-
-    if prefix == HTTP_HEADERS_PREFIX then
-      local name = field:sub(PREFIX_LEN + 1)
-
-      f = function(params)
-        if not params.headers then
-          params.headers = get_http_params(get_headers, "headers", "lua_max_req_headers")
-        end
-
-        return params.headers[name]
-      end -- f
-
-      funcs[field] = f
-      return f
-    end -- if prefix == HTTP_HEADERS_PREFIX
-
-    -- generate for http.queries.*
-
-    if prefix == HTTP_QUERIES_PREFIX then
-      local name = field:sub(PREFIX_LEN + 1)
-
-      f = function(params)
-        if not params.queries then
-          params.queries = get_http_params(get_uri_args, "queries", "lua_max_uri_args")
-        end
-
-        return params.queries[name]
-      end -- f
-
-      funcs[field] = f
-      return f
-    end -- if prefix == HTTP_QUERIES_PREFIX
-
-    -- generate for http.path.segments.*
+  local function gen_http_queries_field_accessor(name)
+    return function(params)
+      if not params.queries then
+        params.queries = get_http_params(get_uri_args, "queries", "lua_max_uri_args")
+      end
 
-    if field:sub(1, HTTP_SEGMENTS_PREFIX_LEN) == HTTP_SEGMENTS_PREFIX then
-      local range = field:sub(HTTP_SEGMENTS_PREFIX_LEN + 1)
+      return params.queries[name]
+    end
+  end
 
-      f = function(params)
-        local segments = get_http_segments(params)
+  local function gen_http_segments_field_accessor(range)
+    return function(params)
+      local segments = get_http_segments(params)
 
         local value = segments[range]
 
@@ -359,9 +332,47 @@ if is_http then
         segments[range] = value
 
         return value
-      end -- f
+    end
+  end
+
+  get_field_accessor = function(funcs, field)
+    local f = FIELDS_FUNCS[field] or funcs[field]
+    if f then
+      return f
+    end
 
+    local prefix = field:sub(1, PREFIX_LEN)
+
+    -- generate for http.headers.*
+
+    if prefix == HTTP_HEADERS_PREFIX then
+      local name = field:sub(PREFIX_LEN + 1)
+
+      f = gen_http_headers_field_accessor(name)
       funcs[field] = f
+
+      return f
+    end -- if prefix == HTTP_HEADERS_PREFIX
+
+    -- generate for http.queries.*
+
+    if prefix == HTTP_QUERIES_PREFIX then
+      local name = field:sub(PREFIX_LEN + 1)
+
+      f = gen_http_queries_field_accessor(name)
+      funcs[field] = f
+
+      return f
+    end -- if prefix == HTTP_QUERIES_PREFIX
+
+    -- generate for http.path.segments.*
+
+    if field:sub(1, HTTP_SEGMENTS_PREFIX_LEN) == HTTP_SEGMENTS_PREFIX then
+      local range = field:sub(HTTP_SEGMENTS_PREFIX_LEN + 1)
+
+      f = gen_http_segments_field_accessor(range)
+      funcs[field] = f
+
       return f
     end -- if field:sub(1, HTTP_SEGMENTS_PREFIX_LEN)