platform_bionic/libc/stdio/stdio_ext.cpp
Elliott Hughes 8c4994bbc1 Implement __fsetlocking.
The old __isthreaded hack was never very useful on Android because all user
code runs in a VM where there are lots of threads running. But __fsetlocking
lets a caller say "I'll worry about the locking for this FILE*", which is
useful for the normal case where you don't share a FILE* between threads
so you don't need any locking.

Bug: 17154740
Bug: 18593728
Change-Id: I2a8dddc29d3edff39a3d7d793387f2253608a68d
2015-01-21 10:33:30 -08:00

101 lines
2.9 KiB
C++

/*
* Copyright (C) 2014 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <stdio_ext.h>
#include <stdlib.h>
#include "local.h"
#include "private/libc_logging.h"
size_t __fbufsize(FILE* fp) {
return fp->_bf._size;
}
/* For a _SRW stream, we don't know whether we last read or wrote.
int __freading(FILE* fp) {
return (fp->_flags & _SRD) != 0 || ...;
}
*/
/* For a _SRW stream, we don't know whether we last read or wrote.
int __fwriting(FILE*) {
return (fp->_flags & _SWR) != 0 || ...;
}
*/
int __freadable(FILE* fp) {
return (fp->_flags & (__SRD|__SRW)) != 0;
}
int __fwritable(FILE* fp) {
return (fp->_flags & (__SWR|__SRW)) != 0;
}
int __flbf(FILE* fp) {
return (fp->_flags & __SLBF) != 0;
}
void __fpurge(FILE* fp) {
fpurge(fp);
}
size_t __fpending(FILE* fp) {
return fp->_p - fp->_bf._base;
}
void _flushlbf() {
// If we flush all streams, we know we've flushed all the line-buffered streams.
fflush(NULL);
}
int __fsetlocking(FILE* fp, int type) {
int old_state = _EXT(fp)->_stdio_handles_locking ? FSETLOCKING_INTERNAL : FSETLOCKING_BYCALLER;
if (type == FSETLOCKING_QUERY) {
return old_state;
}
if (type != FSETLOCKING_INTERNAL && type != FSETLOCKING_BYCALLER) {
// The API doesn't let us report an error, so blow up.
__libc_fatal("Bad type (%d) passed to __fsetlocking", type);
}
_EXT(fp)->_stdio_handles_locking = (type == FSETLOCKING_INTERNAL);
return old_state;
}
void clearerr_unlocked(FILE* fp) {
return __sclearerr(fp);
}
int feof_unlocked(FILE* fp) {
return __sfeof(fp);
}
int ferror_unlocked(FILE* fp) {
return __sferror(fp);
}