Avoid dynamic table field creation in degraded mode

Also avoid copy of sentinel values to be able to use them in event callback.

lib/hpack_tbl.c

@@ -65,8 +65,6 @@ static const struct hpt_field hpt_static[] = {
 const char *hpack_unknown_name = "unknown_name";
 const char *hpack_unknown_value = "unknown_value";
 
-static size_t HPT_index_silent(HPACK_CTX);
-
 static struct hpt_entry *
 hpt_dynamic(struct hpack *hp, size_t idx)
 {
@@ -77,7 +75,9 @@ hpt_dynamic(struct hpack *hp, size_t idx)
 	off = 0;
 
 	assert(idx > 0);
-	assert(idx <= hp->cnt);
+    if(idx > hp->cnt) {
+        return NULL;
+    }
 
 	while (1) {
 		(void)memcpy(&tmp, he, HPT_HEADERSZ);
@@ -109,18 +109,16 @@ HPT_field(HPACK_CTX, size_t idx, struct hpt_field *hf)
 	    ctx->fld.val = hpack_unknown_value;
 	    ctx->fld.nam_sz = strlen(ctx->fld.nam);
 	    ctx->fld.val_sz = strlen(ctx->fld.val);
-        while(idx > ctx->hp->cnt) {
-            HPT_index_silent(ctx);
-        }
-        while(idx >= ctx->hp->cnt) {
-            HPT_index(ctx);
-        }
         if(ctx->hp->flags & HPACK_CFG_SEND_ERR)
             HPC_notify(ctx, HPACK_EVT_RECERR, ctx->ptr.blk, idx);
+    } else {
+        EXPECT(ctx, IDX, idx <= ctx->hp->cnt);
     }
-	EXPECT(ctx, IDX, idx <= ctx->hp->cnt);
 
 	he = hpt_dynamic(ctx->hp, idx);
+    if(HPC_DEGRADED() && he == NULL) {
+        return (0);
+    }
 	assert(he != NULL);
 	assert(hf != NULL);
 	(void)memcpy(&tmp, he, HPT_HEADERSZ);
@@ -385,8 +383,8 @@ hpt_move_evicted(HPACK_CTX, const char *nam, size_t nam_sz, size_t len)
 	(void)memmove(MOVE(tbl_ptr, len), tbl_ptr, hp->sz.len);
 }
 
-static size_t
-HPT_index_silent(HPACK_CTX)
+void
+HPT_index(HPACK_CTX)
 {
 	struct hpack *hp;
 	void *nam_ptr, *val_ptr;
@@ -410,7 +408,7 @@ HPT_index_silent(HPACK_CTX)
 
 	len = HPACK_OVERHEAD + nam_sz + val_sz;
 	if (!hpt_fit(ctx, len))
-		return 0;
+		return;
 
 	nam_ptr = JUMP(hp->tbl, 0);
 	val_ptr = JUMP(hp->tbl, nam_sz + 1);
@@ -431,18 +429,11 @@ HPT_index_silent(HPACK_CTX)
 	hp->tbl->val_sz = (uint16_t)val_sz;
 	hp->sz.len += len;
 	hp->cnt++;
-    return len;
-}
-
-void
-HPT_index(HPACK_CTX)
-{
-    size_t len = HPT_index_silent(ctx);
-    if(len > 0) {
+    if(len > 0)
     	HPC_notify(ctx, HPACK_EVT_INDEX, NULL, len);
-    }
 }
 
+
 /**********************************************************************
  * Decode
  */
@@ -455,17 +446,24 @@ HPT_decode(HPACK_CTX, size_t idx)
 	EXPECT(ctx, IDX, idx > 0);
 	(void)memset(&hf, 0, sizeof hf);
 	CALL(HPT_field, ctx, idx, &hf);
-	assert(hf.nam != NULL);
-	assert(hf.val != NULL);
-	assert(hf.nam_sz > 0);
-
-	ctx->fld.nam = ctx->buf;
-	ctx->fld.nam_sz = hf.nam_sz;
-	CALL(HPD_puts, ctx, hf.nam, hf.nam_sz);
-
-	ctx->fld.val = ctx->buf;
-	ctx->fld.val_sz = hf.val_sz;
-	CALL(HPD_puts, ctx, hf.val, hf.val_sz);
+    if(HPC_DEGRADED() && hf.nam == NULL) {
+        ctx->fld.nam = hpack_unknown_name;
+        ctx->fld.nam_sz = strlen(hpack_unknown_name);
+        ctx->fld.val = hpack_unknown_value;
+        ctx->fld.val_sz = strlen(hpack_unknown_value);
+    } else {
+        assert(hf.nam != NULL);
+        assert(hf.val != NULL);
+        assert(hf.nam_sz > 0);
+
+        ctx->fld.nam = ctx->buf;
+        ctx->fld.nam_sz = hf.nam_sz;
+        CALL(HPD_puts, ctx, hf.nam, hf.nam_sz);
+
+        ctx->fld.val = ctx->buf;
+        ctx->fld.val_sz = hf.val_sz;
+        CALL(HPD_puts, ctx, hf.val, hf.val_sz);
+    }
 
 	HPD_notify(ctx);
 	return (0);
@@ -480,6 +478,9 @@ HPT_decode_name(HPACK_CTX)
 	assert(ctx->hp->state.idx != 0);
 	(void)memset(&hf, 0, sizeof hf);
 	CALL(HPT_field, ctx, ctx->hp->state.idx, &hf);
+    if(HPC_DEGRADED() && hf.nam == NULL) {
+        return (0);
+    }
 	assert(hf.nam != NULL);
 	assert(hf.nam_sz > 0);