# HG changeset patch
# User Roman Arutyunyan <arut@nginx.com>
# Date 1644839674 -10800
# Node ID 8d11e21716978223f37657001c9c0e7f8723be23
# Parent  b5656025ddb5a49de70cf38c1a1a994155a910e8
QUIC: optimize insertion at the end of QUIC buffer.

diff --git a/src/event/quic/ngx_event_quic.h b/src/event/quic/ngx_event_quic.h
--- a/src/event/quic/ngx_event_quic.h
+++ b/src/event/quic/ngx_event_quic.h
@@ -51,7 +51,9 @@ typedef enum {
 typedef struct {
     uint64_t                       size;
     uint64_t                       offset;
+    uint64_t                       last_offset;
     ngx_chain_t                   *chain;
+    ngx_chain_t                  **last_chain;
 } ngx_quic_buffer_t;
 
 
diff --git a/src/event/quic/ngx_event_quic_frames.c b/src/event/quic/ngx_event_quic_frames.c
--- a/src/event/quic/ngx_event_quic_frames.c
+++ b/src/event/quic/ngx_event_quic_frames.c
@@ -421,6 +421,10 @@ ngx_quic_read_buffer(ngx_connection_t *c
         qb->offset += n;
     }
 
+    if (qb->offset >= qb->last_offset) {
+        qb->last_chain = NULL;
+    }
+
     qb->chain = *ll;
     *ll = NULL;
 
@@ -462,6 +466,10 @@ ngx_quic_skip_buffer(ngx_connection_t *c
     if (qb->chain == NULL) {
         qb->offset = offset;
     }
+
+    if (qb->offset >= qb->last_offset) {
+        qb->last_chain = NULL;
+    }
 }
 
 
@@ -493,8 +501,14 @@ ngx_quic_write_buffer(ngx_connection_t *
     ngx_buf_t    *b;
     ngx_chain_t  *cl, **chain;
 
-    base = qb->offset;
-    chain = &qb->chain;
+    if (qb->last_chain && offset >= qb->last_offset) {
+        base = qb->last_offset;
+        chain = qb->last_chain;
+
+    } else {
+        base = qb->offset;
+        chain = &qb->chain;
+    }
 
     while (in && limit) {
 
@@ -585,6 +599,9 @@ ngx_quic_write_buffer(ngx_connection_t *
         }
     }
 
+    qb->last_offset = base;
+    qb->last_chain = chain;
+
     return in;
 }