mirror of
https://sourceware.org/git/glibc.git
synced 2025-11-03 20:53:13 +03:00
73 lines
2.9 KiB
C
73 lines
2.9 KiB
C
/* Flush wrapper for struct __*printf_buffer. Generic version.
|
|
Copyright (C) 2022-2025 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library.
|
|
|
|
The GNU C Library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation; either
|
|
version 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU C Library 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
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with the GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
#include <printf_buffer.h>
|
|
|
|
#include <assert.h>
|
|
#include <stdint.h>
|
|
|
|
/* Xprintf (buffer_do_flush) (BUF) performs the flush operation. The
|
|
actual implementation is specific to the multibyte and wide
|
|
variants.
|
|
|
|
If the flush fails, Xprintf_buffer_mark_failed (BUF) must be
|
|
called, and BUF->write_ptr and BUF->write_end can be left
|
|
unchanged.
|
|
|
|
The function must not do anything if failure has already occurred,
|
|
that is, if BUF->mode == Xprintf (buffer_mode_failed).
|
|
|
|
The framework implicitly invokes flush with BUF->write_ptr ==
|
|
BUF->write_end only. (This is particularly relevant to the
|
|
__sprintf_chk flush, which just calls __chk_fail.) But in some
|
|
cases, Xprintf_buffer_flush may be called explicitly (when
|
|
BUF->mode/the backing function is known). In that case, it is
|
|
possible that BUF->write_ptr < BUF->write_end is true.
|
|
|
|
If the flush succeeds, the pointers are changed so that
|
|
BUF->write_ptr < BUF->write_end. It is possible to switch to a
|
|
completely different buffer here. If the buffer is moved, it may
|
|
be necessary to updated BUF->write_base and BUF->written from the
|
|
flush function as well.
|
|
|
|
Note that when chaining buffers, in the flush function for the
|
|
outer buffer (to which data is written first), it is necessary to
|
|
check for BUF->next->failed (for the inner buffer) and set
|
|
BUF->base.failed to true (for the outer buffer). This should come
|
|
towards the end of the outer flush function. Usually, there is
|
|
also some unwrapping step afterwards; it has to check the outer
|
|
buffer (BUF->base.failed) and propagate any error to the inner
|
|
buffer (BUF->next->failed), so essentially in the other
|
|
direction. */
|
|
static void Xprintf (buffer_do_flush) (struct Xprintf_buffer *buf);
|
|
|
|
bool
|
|
Xprintf_buffer_flush (struct Xprintf_buffer *buf)
|
|
{
|
|
if (__glibc_unlikely (Xprintf_buffer_has_failed (buf)))
|
|
return false;
|
|
|
|
Xprintf (buffer_do_flush) (buf);
|
|
if (Xprintf_buffer_has_failed (buf))
|
|
return false;
|
|
|
|
/* Ensure that the flush has made available some bytes. */
|
|
assert (buf->write_ptr != buf->write_end);
|
|
return true;
|
|
}
|