Be more systematic about the returns from VGZ_Unzip() and pay attention

to the VGZ_STUCK indication.

Hopefully helps with #869

bin/varnishd/cache.h

@@ -690,6 +690,12 @@ int VGZ_Gunzip(struct vgz *, const void **, size_t *len);
 void VGZ_Destroy(struct vgz **);
 void VGZ_UpdateObj(const struct vgz*, struct object *);
 
+/* Return values */
+#define VGZ_ERROR	-1
+#define VGZ_OK		0
+#define VGZ_END		1
+#define VGZ_STUCK	2
+
 /* cache_http.c */
 unsigned HTTP_estimate(unsigned nhttp);
 void HTTP_Copy(struct http *to, const struct http * const fm);

bin/varnishd/cache_esi_deliver.c

@@ -274,7 +274,7 @@ ESI_Deliver(struct sess *sp)
 		VGZ_Ibuf(vgz, gzip_hdr, sizeof gzip_hdr);
 		VGZ_Obuf(vgz, obuf, sizeof obuf);
 		i = VGZ_Gunzip(vgz, &dp, &dl);
-		assert(i == Z_OK || i == Z_STREAM_END);
+		assert(i == VGZ_OK);
 		assert(VGZ_IbufEmpty(vgz));
 		assert(dl == 0);
 
@@ -321,16 +321,20 @@ ESI_Deliver(struct sess *sp)
 				AN(vgz);
 				VGZ_Ibuf(vgz, st->ptr + off, l);
 				do {
-					if (obufl == sizeof obuf) {
-						WRW_Write(sp->wrk, obuf, obufl);
-						obufl = 0;
-					}
 					VGZ_Obuf(vgz, obuf + obufl,
 					    sizeof obuf - obufl);
 					i = VGZ_Gunzip(vgz, &dp, &dl);
-					assert(i == Z_OK || i == Z_STREAM_END);
+					assert(i >= VGZ_OK);
 					obufl += dl;
+					assert(obufl <= sizeof obuf);
+					if (obufl == sizeof obuf ||
+					    i == VGZ_STUCK) {
+						WRW_Write(sp->wrk, obuf, obufl);
+						WRW_Flush(sp->wrk);
+						obufl = 0;
+					}
 				} while (!VGZ_IbufEmpty(vgz));
+				assert (i == VGZ_OK || i == VGZ_END);
 			} else {
 				/*
 				 * Ungzip'ed VEC, ungzip'ed ESI response

bin/varnishd/cache_esi_fetch.c

@@ -39,7 +39,6 @@ SVNID("$Id")
 #include "cache.h"
 #include "cache_esi.h"
 #include "vct.h"
-#include "vgz.h"
 #include "stevedore.h"
 
 /*---------------------------------------------------------------------
@@ -120,7 +119,7 @@ vfp_esi_bytes_gu(struct sess *sp, struct http_conn *htc, ssize_t bytes)
 		if (VGZ_ObufStorage(sp, vg))
 			return (-1);
 		i = VGZ_Gunzip(vg, &dp, &dl);
-		xxxassert(i == Z_OK || i == Z_STREAM_END);
+		xxxassert(i == VGZ_OK || i == VGZ_END);
 		VEP_parse(sp, dp, dl);
 		sp->obj->len += dl;
 	}
@@ -274,7 +273,7 @@ vfp_esi_bytes_gg(struct sess *sp, struct http_conn *htc, size_t bytes)
 			VGZ_Obuf(sp->wrk->vgz_rx, ibuf2, sizeof ibuf2);
 			i = VGZ_Gunzip(sp->wrk->vgz_rx, &dp, &dl);
 			/* XXX: check i */
-			assert(i >= 0);
+			assert(i >= VGZ_OK);
 			vef->bufp = ibuf2;
 			if (dl > 0)
 				VEP_parse(sp, ibuf2, dl);

bin/varnishd/cache_gzip.c

@@ -300,13 +300,13 @@ VGZ_Gunzip(struct vgz *vg, const void **pptr, size_t *plen)
 			vg->obuf->len += l;
 	}
 	if (i == Z_OK)
-		return (0);
+		return (VGZ_OK);
 	if (i == Z_STREAM_END)
-		return (1);
+		return (VGZ_END);
 	if (i == Z_BUF_ERROR)
-		return (2);
+		return (VGZ_STUCK);
 printf("INFLATE=%d (%s)\n", i, vg->vz.msg);
-	return (-1);
+	return (VGZ_ERROR);
 }
 
 /*--------------------------------------------------------------------*/
@@ -432,7 +432,7 @@ vfp_gunzip_bytes(struct sess *sp, struct http_conn *htc, ssize_t bytes)
 		if (VGZ_ObufStorage(sp, vg))
 			return (-1);
 		i = VGZ_Gunzip(vg, &dp, &dl);
-		assert(i == Z_OK || i == Z_STREAM_END);
+		assert(i == VGZ_OK || i == VGZ_END);
 		sp->obj->len += dl;
 	}
 	if (i == Z_OK || i == Z_STREAM_END)
@@ -584,7 +584,7 @@ vfp_testgzip_bytes(struct sess *sp, struct http_conn *htc, ssize_t bytes)
 		while (!VGZ_IbufEmpty(vg)) {
 			VGZ_Obuf(vg, ibuf, sizeof ibuf);
 			i = VGZ_Gunzip(vg, &dp, &dl);
-			if (i != Z_OK && i != Z_STREAM_END) {
+			if (i != VGZ_OK && i != VGZ_END) {
 				WSP(sp, SLT_FetchError,
 				    "Invalid Gzip data: %s", vg->vz.msg);
 				return (-1);

bin/varnishd/cache_response.c

@@ -266,13 +266,13 @@ res_WriteGunzipObj(struct sess *sp)
 		do {
 			VGZ_Obuf(vg, obuf, sizeof obuf);
 			i = VGZ_Gunzip(vg, &dp, &dl);
+			assert(i >= VGZ_OK);
 			if (dl != 0) {
 				(void)WRW_Write(sp->wrk, dp, dl);
 				if (WRW_Flush(sp->wrk))
 					break;
 			}
-			assert(i >= 0);
-		} while (i == 0);
+		} while (!VGZ_IbufEmpty(vg));
 	}
 	VGZ_Destroy(&vg);
 	assert(u == sp->obj->len);