Add a stream_context structure to hold the state for streaming

when we need it.

bin/varnishd/cache.h

@@ -247,7 +247,6 @@ struct exp {
 
 /*--------------------------------------------------------------------*/
 
-/* WRW related fields */
 struct wrw {
 	int			*wfd;
 	unsigned		werr;	/* valid after WRK_Flush() */
@@ -259,6 +258,21 @@ struct wrw {
 	unsigned		ciov;	/* Chunked header marker */
 };
 
+/*--------------------------------------------------------------------*/
+
+struct stream_ctx {
+	unsigned		magic;
+#define STREAM_CTX_MAGIC	0x8213728b
+#if 0
+	struct vgz		*vgz;
+	void			*obuf;
+	ssize_t			obuf_len;
+	ssize_t			obuf_ptr;
+#endif
+	ssize_t			stream_next;
+};
+
+/*--------------------------------------------------------------------*/
 struct worker {
 	unsigned		magic;
 #define WORKER_MAGIC		0x6391adcf
@@ -312,7 +326,7 @@ struct worker {
 	char			*h_content_length;
 
 	/* Stream state */
-	ssize_t			stream_next;
+	struct stream_ctx	*sctx;
 
 	/* ESI stuff */
 	struct vep_state	*vep;

bin/varnishd/cache_center.c

@@ -839,6 +839,13 @@ static int
 cnt_streambody(struct sess *sp)
 {
 	int i;
+	struct stream_ctx sctx;
+
+
+	memset(&sctx, 0, sizeof sctx);
+	sctx.magic = STREAM_CTX_MAGIC;
+	AZ(sp->wrk->sctx);
+	sp->wrk->sctx = &sctx;
 
 	RES_StreamStart(sp);
 
@@ -854,6 +861,7 @@ cnt_streambody(struct sess *sp)
 	AN(sp->director);
 
 	if (i) {
+		sp->wrk->sctx = NULL;
 		HSH_Drop(sp);
 		AZ(sp->obj);
 		sp->err_code = 503;
@@ -873,6 +881,7 @@ cnt_streambody(struct sess *sp)
 
 	RES_StreamEnd(sp);
 
+	sp->wrk->sctx = NULL;
 	assert(WRW_IsReleased(sp->wrk));
 	assert(sp->wrk->wrw.ciov == sp->wrk->wrw.siov);
 	(void)HSH_Deref(sp->wrk, NULL, &sp->obj);

bin/varnishd/cache_response.c

@@ -394,6 +394,10 @@ RES_WriteObj(struct sess *sp)
 void
 RES_StreamStart(struct sess *sp)
 {
+	struct stream_ctx *sctx;
+
+	sctx = sp->wrk->sctx;
+	CHECK_OBJ_NOTNULL(sctx, STREAM_CTX_MAGIC);
 
 	AZ(sp->wrk->res_mode & RES_ESI_CHILD);
 	AN(sp->wantbody);
@@ -410,31 +414,32 @@ RES_StreamStart(struct sess *sp)
 
 	if (sp->wrk->res_mode & RES_CHUNKED)
 		WRW_Chunked(sp->wrk);
-
-	sp->wrk->stream_next = 0;
 }
 
 void
 RES_StreamPoll(const struct sess *sp)
 {
+	struct stream_ctx *sctx;
 	struct storage *st;
 	ssize_t l, l2;
 	void *ptr;
 
-	if (sp->obj->len == sp->wrk->stream_next)
+	sctx = sp->wrk->sctx;
+	CHECK_OBJ_NOTNULL(sctx, STREAM_CTX_MAGIC);
+	if (sp->obj->len == sctx->stream_next)
 		return;
-	assert(sp->obj->len > sp->wrk->stream_next);
+	assert(sp->obj->len > sctx->stream_next);
 	l = 0;
 	VTAILQ_FOREACH(st, &sp->obj->store, list) {
-		if (st->len + l <= sp->wrk->stream_next) {
+		if (st->len + l <= sctx->stream_next) {
 			l += st->len;
 			continue;
 		}
-		l2 = st->len + l - sp->wrk->stream_next;
-		ptr = st->ptr + (sp->wrk->stream_next - l);
+		l2 = st->len + l - sctx->stream_next;
+		ptr = st->ptr + (sctx->stream_next - l);
 		(void)WRW_Write(sp->wrk, ptr, l2);
 		l += st->len;
-		sp->wrk->stream_next += l2;
+		sctx->stream_next += l2;
 	}
 	(void)WRW_Flush(sp->wrk);
 }
@@ -442,6 +447,10 @@ RES_StreamPoll(const struct sess *sp)
 void
 RES_StreamEnd(struct sess *sp)
 {
+	struct stream_ctx *sctx;
+
+	sctx = sp->wrk->sctx;
+	CHECK_OBJ_NOTNULL(sctx, STREAM_CTX_MAGIC);
 
 	if (sp->wrk->res_mode & RES_GUNZIP) {
 		INCOMPL();