lib9p_srv: Rethink the dio interface

1 files changed, 65 insertions, 19 deletions

diff --git a/lib9p/srv.c b/lib9p/srv.c
index b5455e0..96954aa 100644
--- a/lib9p/srv.c
+++ b/lib9p/srv.c
@@ -108,6 +108,7 @@ struct srv_fidinfo {
 			lo_interface lib9p_srv_dio              io;
 			size_t                                  idx;
 			uint64_t                                off;
+			struct lib9p_srv_dirent                 buffered_dirent;
 		}                                       dir;
 		struct {
 			struct lib9p_s                          aname;
@@ -1163,32 +1164,77 @@ static void handle_Tread(struct srv_req *ctx,
 	ctx->user = srv_userid_incref(fidinfo->user);
 	switch (fidinfo->type) {
 	case SRV_FILETYPE_DIR:
-		/* Translate byte-offset to object-index. */
-		size_t idx;
-		if (req->offset == 0)
-			idx = 0;
-		else if (req->offset == fidinfo->dir.off)
-			idx = fidinfo->dir.idx;
-		else {
+		/* Seek.  */
+		if (req->offset == 0) {
+			fidinfo->dir.idx = 0;
+			fidinfo->dir.off = 0;
+			fidinfo->dir.buffered_dirent = (struct lib9p_srv_dirent){};
+		} else if (req->offset != fidinfo->dir.off) {
 			lib9p_errorf(&ctx->basectx,
 			             LIB9P_ERRNO_L_EINVAL, "invalid offset (must be 0 or %"PRIu64"): %"PRIu64,
 			             fidinfo->dir.off, req->offset);
 			goto tread_return;
 		}
-		/* Do it.  */
+		/* Read.  */
 		resp.data = heap = malloc(req->count); /* TODO: cap req->count */
-		size_t num = LO_CALL(fidinfo->dir.io, dread, ctx, (uint8_t *)resp.data, req->count, idx);
-		/* Translate object-count back to byte-count.  */
-		uint32_t len = 0;
-		for (size_t i = 0; i < num; i++) {
-			uint32_t i_len;
-			lib9p_stat_validate(&ctx->basectx, req->count, &((uint8_t *)resp.data)[len], &i_len, NULL);
-			len += i_len;
+		resp.count = 0;
+		struct srv_pathinfo *dir_pathinfo = NULL;
+		for (;;) {
+			lo_interface lib9p_srv_file member_file = {};
+			struct lib9p_srv_dirent member_dirent;
+			if (fidinfo->dir.buffered_dirent.name.len) {
+				member_dirent = fidinfo->dir.buffered_dirent;
+			} else {
+				member_dirent = LO_CALL(fidinfo->dir.io, dread, ctx, fidinfo->dir.idx);
+				if (lib9p_ctx_has_error(&ctx->basectx)) {
+					if (!resp.count)
+						goto tread_return;
+					lib9p_ctx_clear_error(&ctx->basectx);
+					break;
+				}
+			}
+			if (!member_dirent.name.len)
+				break;
+			struct lib9p_stat member_stat;
+			struct srv_pathinfo *member_pathinfo = map_load(&ctx->parent_sess->paths, member_dirent.qid.path);
+			if (member_pathinfo) {
+				member_stat = LO_CALL(member_pathinfo->file, stat, ctx);
+			} else {
+				if (!dir_pathinfo)
+					dir_pathinfo = map_load(&ctx->parent_sess->paths, fidinfo->path);
+				assert(dir_pathinfo);
+				member_file = LO_CALL(dir_pathinfo->file, dwalk, ctx, member_dirent.name);
+				assert(LO_IS_NULL(member_file) == lib9p_ctx_has_error(&ctx->basectx));
+				if (!lib9p_ctx_has_error(&ctx->basectx))
+					member_stat = LO_CALL(member_file, stat, ctx);
+			}
+			if (lib9p_ctx_has_error(&ctx->basectx)) {
+				if (!LO_IS_NULL(member_file))
+					LO_CALL(member_file, free);
+				if (!resp.count)
+					goto tread_return;
+				lib9p_ctx_clear_error(&ctx->basectx);
+				break;
+			}
+			lib9p_stat_assert(member_stat);
+			uint32_t nbytes = lib9p_stat_marshal(&ctx->basectx, req->count-resp.count, &member_stat,
+			                                     (uint8_t *)&resp.data[resp.count]);
+			if (!LO_IS_NULL(member_file))
+				LO_CALL(member_file, free);
+			if (!nbytes) {
+				if (!resp.count) {
+					lib9p_error(&ctx->basectx,
+					            LIB9P_ERRNO_L_ERANGE, "stat object does not fit into negotiated max message size");
+					goto tread_return;
+				}
+				fidinfo->dir.buffered_dirent = member_dirent;
+				break;
+			}
+			resp.count += nbytes;
+			fidinfo->dir.idx++;
+			fidinfo->dir.off += nbytes;
+			fidinfo->dir.buffered_dirent = (struct lib9p_srv_dirent){};
 		}
-		resp.count = len;
-		/* Remember.  */
-		fidinfo->dir.idx = idx+num;
-		fidinfo->dir.off = req->offset + len;
 		break;
 	case SRV_FILETYPE_FILE:
 		struct iovec iov;