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Posted to commits@apr.apache.org by pq...@apache.org on 2004/12/11 04:53:08 UTC
svn commit: r111571 - /apr/apr/trunk/CHANGES /apr/apr/trunk/file_io/unix/readwrite.c
Author: pquerna
Date: Fri Dec 10 19:53:06 2004
New Revision: 111571
URL: http://svn.apache.org/viewcvs?view=rev&rev=111571
Log:
* file_io/unix/readwrite.c: Revert to the original code for apr_file writev() in the !HAVE_WRITEV case, and a large comment
explaining why we cannot use a better method without breaking writev()'s semantics.
Modified:
apr/apr/trunk/CHANGES
apr/apr/trunk/file_io/unix/readwrite.c
Modified: apr/apr/trunk/CHANGES
Url: http://svn.apache.org/viewcvs/apr/apr/trunk/CHANGES?view=diff&rev=111571&p1=apr/apr/trunk/CHANGES&r1=111570&p2=apr/apr/trunk/CHANGES&r2=111571
==============================================================================
--- apr/apr/trunk/CHANGES (original)
+++ apr/apr/trunk/CHANGES Fri Dec 10 19:53:06 2004
@@ -10,10 +10,6 @@
*) Add apr_file_writev_full to ensure an entire iovec is writen to a file.
[Paul Querna]
- *) apr_file_writev will now at least try to write all iovecs on platforms
- that do not support writev.
- [Paul Querna]
-
*) Remove the runtime test for Sendfile versions on FreeBSD. PR 25718.
[Mike Silbersack <silby silby.com>, Paul Querna]
Modified: apr/apr/trunk/file_io/unix/readwrite.c
Url: http://svn.apache.org/viewcvs/apr/apr/trunk/file_io/unix/readwrite.c?view=diff&rev=111571&p1=apr/apr/trunk/file_io/unix/readwrite.c&r1=111570&p2=apr/apr/trunk/file_io/unix/readwrite.c&r2=111571
==============================================================================
--- apr/apr/trunk/file_io/unix/readwrite.c (original)
+++ apr/apr/trunk/file_io/unix/readwrite.c Fri Dec 10 19:53:06 2004
@@ -241,21 +241,22 @@
return APR_SUCCESS;
}
#else
- int i;
- int tbytes;
- apr_status_t rv = APR_SUCCESS;
+ /**
+ * The problem with trying to output the entire iovec is that we cannot
+ * maintain the behavoir that a real writev would have. If we iterate
+ * over the iovec one at a time, we loose the atomic properties of
+ * writev(). The other option is to combine the entire iovec into one
+ * buffer that we could then send in one call to write(). This is not
+ * reasonable since we do not know how much data an iocev could contain.
+ *
+ * The only reasonable option, that maintains the semantics of a real
+ * writev(), is to only write the first iovec. Callers of file_writev()
+ * must deal with partial writes as they normally would. If you want to
+ * ensure an entire iovec is written, use apr_file_writev_full().
+ */
- *nbytes = 0;
-
- for (i = 0; i < nvec; i++) {
- tbytes = vec[i].iov_len;
- rv = apr_file_write(thefile, vec[i].iov_base, &tbytes);
- *nbytes += tbytes;
- if (rv != APR_SUCCESS || tbytes < vec[i].iov_len) {
- break;
- }
- }
- return rv;
+ *nbytes = vec[0].iov_len;
+ return apr_file_write(thefile, vec[0].iov_base, nbytes);
#endif
}