nghttp2_hd: Add static table entry to dynamic table on emission

lib/nghttp2_hd.c

@@ -796,7 +796,28 @@ static int deflate_nv(nghttp2_hd_context *deflater,
   if(rv != -1) {
     size_t index = rv;
     ent = nghttp2_hd_table_get(deflater, index);
-    if((ent->flags & NGHTTP2_HD_FLAG_REFSET) == 0) {
+    if(index >= deflater->hd_table.len) {
+      nghttp2_hd_entry *new_ent;
+      /* It is important to first add entry to the header table and
+         let eviction go. If NGHTTP2_HD_FLAG_IMPLICIT_EMIT entry is
+         evicted, it must be emitted before the |nv|. */
+      new_ent = add_hd_table_incremental(deflater, buf_ptr, buflen_ptr,
+                                         offset_ptr, &ent->nv,
+                                         NGHTTP2_HD_FLAG_NONE);
+      if(!new_ent) {
+        return NGHTTP2_ERR_HEADER_COMP;
+      }
+      if(new_ent->ref == 0) {
+        nghttp2_hd_entry_free(new_ent);
+        free(new_ent);
+      } else {
+        new_ent->flags |= NGHTTP2_HD_FLAG_EMIT;
+      }
+      rv = emit_indexed_block(buf_ptr, buflen_ptr, offset_ptr, index);
+      if(rv != 0) {
+        return rv;
+      }
+    } else if((ent->flags & NGHTTP2_HD_FLAG_REFSET) == 0) {
       ent->flags |= NGHTTP2_HD_FLAG_REFSET | NGHTTP2_HD_FLAG_EMIT;
       rv = emit_indexed_block(buf_ptr, buflen_ptr, offset_ptr, index);
       if(rv != 0) {
@@ -859,7 +880,12 @@ static int deflate_nv(nghttp2_hd_context *deflater,
       if(!new_ent) {
         return NGHTTP2_ERR_HEADER_COMP;
       }
-      new_ent->flags |= NGHTTP2_HD_FLAG_EMIT;
+      if(new_ent->ref == 0) {
+        nghttp2_hd_entry_free(new_ent);
+        free(new_ent);
+      } else {
+        new_ent->flags |= NGHTTP2_HD_FLAG_EMIT;
+      }
       incidx = 1;
     }
     if(index == -1) {
@@ -923,14 +949,6 @@ ssize_t nghttp2_hd_deflate_hd(nghttp2_hd_context *deflater,
       goto fail;
     }
   }
-  for(i = 0; deflater->static_hd_table[i]; ++i) {
-    nghttp2_hd_entry *ent = deflater->static_hd_table[i];
-    rv = deflate_post_process_hd_entry(ent, i + deflater->hd_table.len,
-                                       buf_ptr, buflen_ptr, &offset);
-    if(rv != 0) {
-      goto fail;
-    }
-  }
   return offset - nv_offset;
  fail:
   deflater->bad = 1;
@@ -1003,12 +1021,25 @@ ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_context *inflater,
         goto fail;
       }
       ent = nghttp2_hd_table_get(inflater, index);
-      ent->flags ^= NGHTTP2_HD_FLAG_REFSET;
-      if(ent->flags & NGHTTP2_HD_FLAG_REFSET) {
-        rv = emit_indexed_header(inflater, &nva_out, ent);
-        if(rv != 0) {
+      if(index >= (ssize_t)inflater->hd_table.len) {
+        nghttp2_hd_entry *new_ent;
+        new_ent = add_hd_table_incremental(inflater, NULL, NULL, NULL,
+                                           &ent->nv, NGHTTP2_HD_FLAG_NONE);
+        if(!new_ent) {
+          rv = NGHTTP2_ERR_HEADER_COMP;
           goto fail;
         }
+        /* new_ent->ref == 0 may be hold but emit_indexed_header
+           tracks new_ent, so there is no leak. */
+        rv = emit_indexed_header(inflater, &nva_out, new_ent);
+      } else {
+        ent->flags ^= NGHTTP2_HD_FLAG_REFSET;
+        if(ent->flags & NGHTTP2_HD_FLAG_REFSET) {
+          rv = emit_indexed_header(inflater, &nva_out, ent);
+        }
+      }
+      if(rv != 0) {
+        goto fail;
       }
     } else if(c == 0x40u || c == 0) {
       /* Literal Header Repr - New Name */
@@ -1191,13 +1222,6 @@ ssize_t nghttp2_hd_inflate_hd(nghttp2_hd_context *inflater,
       goto fail;
     }
   }
-  for(i = 0; inflater->static_hd_table[i]; ++i) {
-    nghttp2_hd_entry *ent = inflater->static_hd_table[i];
-    rv = inflater_post_process_hd_entry(inflater, ent, &nva_out);
-    if(rv != 0) {
-      goto fail;
-    }
-  }
   nghttp2_nv_array_sort(nva_out.nva, nva_out.nvlen);
   *nva_ptr = nva_out.nva;
   return nva_out.nvlen;

tests/nghttp2_hd_test.c

@@ -198,13 +198,13 @@ void test_nghttp2_hd_deflate_common_header_eviction(void)
   size_t buflen = 0;
   ssize_t blocklen;
   nghttp2_nv *resnva;
-  /* Default header table capacity is 1262. Adding 2835 bytes,
-     including overhead, to the table evicts first entry.
-     use name ":host" which index 2 and value length 2798. */
-  uint8_t value[2798];
+  /* Default header table capacity is 4096. Adding 2 byte header name
+     and 4060 byte value, which is 4094 bytes including overhead, to
+     the table evicts first entry. */
+  uint8_t value[4060];
 
   memset(value, '0', sizeof(value));
-  nva[1].name = (uint8_t*)":host";
+  nva[1].name = (uint8_t*)"hd";
   nva[1].namelen = strlen((const char*)nva[1].name);
   nva[1].value = value;
   nva[1].valuelen = sizeof(value);
@@ -212,11 +212,20 @@ void test_nghttp2_hd_deflate_common_header_eviction(void)
   nghttp2_hd_deflate_init(&deflater, NGHTTP2_HD_SIDE_REQUEST);
   nghttp2_hd_inflate_init(&inflater, NGHTTP2_HD_SIDE_REQUEST);
 
-  /* Put :scheme: http (index = 0) in reference set */
-  GET_TABLE_ENT(&deflater, 0)->flags |= NGHTTP2_HD_FLAG_REFSET;
-  GET_TABLE_ENT(&inflater, 0)->flags |= NGHTTP2_HD_FLAG_REFSET;
-  blocklen = nghttp2_hd_deflate_hd(&deflater, &buf, &buflen, 0, nva,
-                                   sizeof(nva)/sizeof(nghttp2_nv));
+  /* First emit ":scheme: http" to put it in the reference set (index
+     = 0). */
+  blocklen = nghttp2_hd_deflate_hd(&deflater, &buf, &buflen, 0, nva, 1);
+  CU_ASSERT(blocklen > 0);
+  nghttp2_hd_end_headers(&deflater);
+
+  CU_ASSERT(1 == nghttp2_hd_inflate_hd(&inflater, &resnva, buf, blocklen));
+  nghttp2_nv_array_sort(nva, 1);
+  assert_nv_equal(nva, resnva, 1);
+  nghttp2_nv_array_del(resnva);
+  nghttp2_hd_end_headers(&inflater);
+
+  /* Encode with large header */
+  blocklen = nghttp2_hd_deflate_hd(&deflater, &buf, &buflen, 0, nva, 2);
   CU_ASSERT(blocklen > 0);
   nghttp2_hd_end_headers(&deflater);
 
@@ -230,6 +239,9 @@ void test_nghttp2_hd_deflate_common_header_eviction(void)
   nghttp2_nv_array_del(resnva);
   nghttp2_hd_end_headers(&inflater);
 
+  CU_ASSERT(1 == deflater.hd_table.len);
+  CU_ASSERT(1 == inflater.hd_table.len);
+
   free(buf);
   nghttp2_hd_inflate_free(&inflater);
   nghttp2_hd_deflate_free(&deflater);