From: Stefan Beller <sbeller@google.com>
To: git@vger.kernel.org
Cc: Stefan Beller <sbeller@google.com>,
ramsay@ramsayjones.plus.com, jacob.keller@gmail.com,
peff@peff.net, gitster@pobox.com, jrnieder@gmail.com,
johannes.schindelin@gmail.com, Jens.Lehmann@web.de,
ericsunshine@gmail.com
Subject: [PATCH 4/8] strbuf: add strbuf_read_once to read without blocking
Date: Mon, 28 Sep 2015 16:14:02 -0700 [thread overview]
Message-ID: <1443482046-25569-5-git-send-email-sbeller@google.com> (raw)
In-Reply-To: <1443482046-25569-1-git-send-email-sbeller@google.com>
The new call will read from a file descriptor into a strbuf once. The
underlying call xread_nonblock is meant to execute without blocking if
the file descriptor is set to O_NONBLOCK. It is a bug to call
strbuf_read_once on a file descriptor which would block.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
strbuf.c | 11 +++++++++++
strbuf.h | 9 +++++++++
2 files changed, 20 insertions(+)
diff --git a/strbuf.c b/strbuf.c
index cce5eed..35e71b8 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -384,6 +384,17 @@ ssize_t strbuf_read(struct strbuf *sb, int fd, size_t hint)
return sb->len - oldlen;
}
+ssize_t strbuf_read_once(struct strbuf *sb, int fd, size_t hint)
+{
+ ssize_t cnt;
+
+ strbuf_grow(sb, hint ? hint : 8192);
+ cnt = xread_nonblock(fd, sb->buf + sb->len, sb->alloc - sb->len - 1);
+ if (cnt > 0)
+ strbuf_setlen(sb, sb->len + cnt);
+ return cnt;
+}
+
#define STRBUF_MAXLINK (2*PATH_MAX)
int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
diff --git a/strbuf.h b/strbuf.h
index aef2794..ea69665 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -367,6 +367,15 @@ extern size_t strbuf_fread(struct strbuf *, size_t, FILE *);
extern ssize_t strbuf_read(struct strbuf *, int fd, size_t hint);
/**
+ * Read from a file descriptor that is marked as O_NONBLOCK without
+ * blocking. Returns the number of new bytes appended to the sb.
+ * Negative return value signals there was an error returned from
+ * underlying read(2), in which case the caller should check errno.
+ * e.g. errno == EAGAIN when the read may have blocked.
+ */
+extern ssize_t strbuf_read_once(struct strbuf *, int fd, size_t hint);
+
+/**
* Read the contents of a file, specified by its path. The third argument
* can be used to give a hint about the file size, to avoid reallocs.
*/
--
2.5.0.273.g6fa2560.dirty
next prev parent reply other threads:[~2015-09-28 23:14 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-09-28 23:13 [PATCH 0/8] fetch submodules in parallel Stefan Beller
2015-09-28 23:13 ` [PATCH 1/8] submodule.c: write "Fetching submodule <foo>" to stderr Stefan Beller
2015-09-28 23:14 ` [PATCH 2/8] xread: poll on non blocking fds Stefan Beller
2015-09-28 23:14 ` [PATCH 3/8] xread_nonblock: add functionality to read from fds without blocking Stefan Beller
2015-09-28 23:14 ` Stefan Beller [this message]
2015-09-28 23:14 ` [PATCH 5/8] sigchain: add command to pop all common signals Stefan Beller
2015-09-30 5:23 ` Junio C Hamano
2015-09-28 23:14 ` [PATCH 6/8] run-command: add an asynchronous parallel child processor Stefan Beller
2015-09-30 3:12 ` Junio C Hamano
2015-09-30 18:28 ` Stefan Beller
2015-09-30 18:48 ` Junio C Hamano
2015-09-28 23:14 ` [PATCH 7/8] fetch_populated_submodules: use new parallel job processing Stefan Beller
2015-09-28 23:14 ` [PATCH 8/8] submodules: allow parallel fetching, add tests and documentation Stefan Beller
-- strict thread matches above, loose matches on Subject: below --
2015-12-14 19:37 [PATCH 0/8] Rerolling sb/submodule-parallel-fetch for the time after 2.7 Stefan Beller
2015-12-14 19:37 ` [PATCH 4/8] strbuf: add strbuf_read_once to read without blocking Stefan Beller
2015-12-14 23:16 ` Eric Sunshine
2015-12-14 23:27 ` Stefan Beller
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