Implement runcap_read functionv1.2

* Make.am (RUNCAP_SRC): Add read.c
* read.c: New file
* runcap.h (runcap_read): New proto.
* t/rt: Expand read request to include a flag for selecting
* t/read.at: New file.
* t/nocap.at: New file
* t/nocap00.at: Remove.
* t/nocap01.at: Remove.
* t/Makefile.am (TESTSUITE_AT): Add new test. Merge two nocap tests
to one.
* t/testsuite.at: Likewise.

1 files changed, 69 insertions, 0 deletions

diff --git a/read.c b/read.c
new file mode 100644
index 0000000..a57d9b9
--- /dev/null
+++ b/read.c
@@ -0,0 +1,69 @@
+/* runcap - run program and capture its output
+   Copyright (C) 2019 Sergey Poznyakoff
+
+   Runcap is free software; you can redistribute it and/or modify it
+   under the terms of the GNU General Public License as published by the
+   Free Software Foundation; either version 3 of the License, or (at your
+   option) any later version.
+
+   Runcap is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License along
+   with Runcap. If not, see <http://www.gnu.org/licenses/>. */
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+#include "runcap.h"
+
+ssize_t
+runcap_read(struct runcap *rc, int sd, char *buf, size_t size)
+{
+	struct stream_capture *cap;
+	ssize_t nread = 0;
+	
+	if (!buf) {
+		errno = EINVAL;
+		return -1;
+	}
+	if (size == 0)
+		return 0;
+
+	cap = runcap_get_capture(rc, sd);
+	if (!cap)
+		return -1;
+	
+	while (size) {
+		size_t avail = cap->sc_level - cap->sc_cur;
+		if (avail == 0) {
+			if (cap->sc_storfd != -1) {
+				ssize_t r = read(cap->sc_storfd,
+						 cap->sc_base,
+						 cap->sc_size);
+				if (r < 0)
+					return -1;
+				else if (r == 0)
+					break;
+				avail = r;
+				cap->sc_level = r;
+				cap->sc_cur = 0;
+			} else {
+				break;
+			}
+		}
+
+		if (avail > size)
+			avail = size;
+		memcpy(buf + nread, cap->sc_base + cap->sc_cur, avail);
+
+		cap->sc_cur += avail;
+		nread += avail;
+		size -= avail;
+	}
+	
+	return nread;
+}