diff options
author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 09:51:24 +0000 |
---|---|---|
committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-28 09:51:24 +0000 |
commit | f7548d6d28c313cf80e6f3ef89aed16a19815df1 (patch) | |
tree | a3f6f2a3f247293bee59ecd28e8cd8ceb6ca064a /src/lib/istream-try.h | |
parent | Initial commit. (diff) | |
download | dovecot-f7548d6d28c313cf80e6f3ef89aed16a19815df1.tar.xz dovecot-f7548d6d28c313cf80e6f3ef89aed16a19815df1.zip |
Adding upstream version 1:2.3.19.1+dfsg1.upstream/1%2.3.19.1+dfsg1upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/lib/istream-try.h')
-rw-r--r-- | src/lib/istream-try.h | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/src/lib/istream-try.h b/src/lib/istream-try.h new file mode 100644 index 0000000..6f0f8b7 --- /dev/null +++ b/src/lib/istream-try.h @@ -0,0 +1,25 @@ +#ifndef ISTREAM_TRY_H +#define ISTREAM_TRY_H + +/* Read from the first input stream that doesn't fail with EINVAL. If any of + the streams fail with non-EINVAL, it's treated as a fatal failure and the + error is immediately returned. If a stream returns 0, more data is waited + for before continuing to the next stream. This allows the last stream to + be a fallback stream that always succeeds. + + Once the stream is detected, all the other streams are unreferenced. + The streams should usually be children of the same parent tee-istream. + + Detecting whether istream-tee buffer is full or not is a bit tricky. + There's no visible difference between non-blocking istream returning 0 and + istream-tee buffer being full. To work around this, we treat used buffer + sizes <= min_buffer_full_size as being non-blocking istreams, while + buffer sizes > min_buffer_full_size are assumed to be due to istream-tee + max buffer size being reached. Practically this means that + min_buffer_full_size must be smaller than the smallest of the istreams' + maximum buffer sizes, but large enough that all the istreams would have + returned EINVAL on invalid input by that position. */ +struct istream *istream_try_create(struct istream *const input[], + size_t min_buffer_full_size); + +#endif |