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/*-
* Copyright (c) 2014-2016 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/* Buffer size for streamed reads/writes. */
#define WT_STREAM_BUFSIZE 8192
/*
* __fstream_close --
* Close a stream handle.
*/
static int
__fstream_close(WT_SESSION_IMPL *session, WT_FSTREAM *fs)
{
WT_DECL_RET;
if (!F_ISSET(fs, WT_STREAM_READ))
WT_TRET(fs->flush(session, fs));
WT_TRET(__wt_close(session, &fs->fh));
__wt_buf_free(session, &fs->buf);
__wt_free(session, fs);
return (ret);
}
/*
* __fstream_flush --
* Flush the data from a stream.
*/
static int
__fstream_flush(WT_SESSION_IMPL *session, WT_FSTREAM *fs)
{
if (fs->buf.size > 0) {
WT_RET(__wt_write(
session, fs->fh, fs->off, fs->buf.size, fs->buf.data));
fs->off += (wt_off_t)fs->buf.size;
fs->buf.size = 0;
}
return (0);
}
/*
* __fstream_flush_notsup --
* Stream flush unsupported.
*/
static int
__fstream_flush_notsup(WT_SESSION_IMPL *session, WT_FSTREAM *fs)
{
WT_RET_MSG(session, ENOTSUP, "%s: flush", fs->name);
}
/*
* __fstream_getline --
* Get a line from a stream.
*
* Implementation of the POSIX getline or BSD fgetln functions (finding the
* function in a portable way is hard, it's simple enough to write it instead).
*
* Note: Unlike the standard getline calls, this function doesn't include the
* trailing newline character in the returned buffer and discards empty lines
* (so the caller's EOF marker is a returned line length of 0).
*/
static int
__fstream_getline(WT_SESSION_IMPL *session, WT_FSTREAM *fs, WT_ITEM *buf)
{
const char *p;
size_t len;
char c;
/*
* We always NUL-terminate the returned string (even if it's empty),
* make sure there's buffer space for a trailing NUL in all cases.
*/
WT_RET(__wt_buf_init(session, buf, 100));
for (;;) {
/* Check if we need to refill the buffer. */
if (WT_PTRDIFF(fs->buf.data, fs->buf.mem) >= fs->buf.size) {
len = WT_MIN(WT_STREAM_BUFSIZE,
(size_t)(fs->size - fs->off));
if (len == 0)
break; /* EOF */
WT_RET(__wt_buf_initsize(session, &fs->buf, len));
WT_RET(__wt_read(
session, fs->fh, fs->off, len, fs->buf.mem));
fs->off += (wt_off_t)len;
}
c = *(p = fs->buf.data);
fs->buf.data = ++p;
/* Leave space for a trailing NUL. */
WT_RET(__wt_buf_extend(session, buf, buf->size + 2));
if (c == '\n') {
if (buf->size == 0)
continue;
break;
}
((char *)buf->mem)[buf->size++] = c;
}
((char *)buf->mem)[buf->size] = '\0';
return (0);
}
/*
* __fstream_getline_notsup --
* Stream getline unsupported.
*/
static int
__fstream_getline_notsup(WT_SESSION_IMPL *session, WT_FSTREAM *fs, WT_ITEM *buf)
{
WT_UNUSED(buf);
WT_RET_MSG(session, ENOTSUP, "%s: getline", fs->name);
}
/*
* __fstream_printf --
* ANSI C vfprintf.
*/
static int
__fstream_printf(
WT_SESSION_IMPL *session, WT_FSTREAM *fs, const char *fmt, va_list ap)
{
WT_ITEM *buf;
va_list ap_copy;
size_t len, space;
char *p;
buf = &fs->buf;
for (;;) {
va_copy(ap_copy, ap);
p = (char *)((uint8_t *)buf->mem + buf->size);
WT_ASSERT(session, buf->memsize >= buf->size);
space = buf->memsize - buf->size;
len = (size_t)vsnprintf(p, space, fmt, ap_copy);
va_end(ap_copy);
if (len < space) {
buf->size += len;
return (buf->size >= WT_STREAM_BUFSIZE ?
__wt_fflush(session, fs) : 0);
}
WT_RET(__wt_buf_extend(session, buf, buf->size + len + 1));
}
}
/*
* __fstream_printf_notsup --
* ANSI C vfprintf unsupported.
*/
static int
__fstream_printf_notsup(
WT_SESSION_IMPL *session, WT_FSTREAM *fs, const char *fmt, va_list ap)
{
WT_UNUSED(fmt);
WT_UNUSED(ap);
WT_RET_MSG(session, ENOTSUP, "%s: printf", fs->name);
}
/*
* __wt_fopen --
* Open a stream handle.
*/
int
__wt_fopen(WT_SESSION_IMPL *session,
const char *name, uint32_t open_flags, uint32_t flags, WT_FSTREAM **fsp)
{
WT_DECL_RET;
WT_FH *fh;
WT_FSTREAM *fs;
fs = NULL;
WT_RET(__wt_open(
session, name, WT_OPEN_FILE_TYPE_REGULAR, open_flags, &fh));
WT_ERR(__wt_calloc_one(session, &fs));
fs->fh = fh;
fs->name = fh->name;
fs->flags = flags;
fs->close = __fstream_close;
WT_ERR(__wt_filesize(session, fh, &fs->size));
if (LF_ISSET(WT_STREAM_APPEND))
fs->off = fs->size;
if (LF_ISSET(WT_STREAM_APPEND | WT_STREAM_WRITE)) {
fs->flush = __fstream_flush;
fs->getline = __fstream_getline_notsup;
fs->printf = __fstream_printf;
} else {
WT_ASSERT(session, LF_ISSET(WT_STREAM_READ));
fs->flush = __fstream_flush_notsup;
fs->getline = __fstream_getline;
fs->printf = __fstream_printf_notsup;
}
*fsp = fs;
return (0);
err: WT_TRET(__wt_close(session, &fh));
__wt_free(session, *fsp);
return (ret);
}
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