Revision 3ebbd00cf3c5a7c6f90e2fed8adaf0c5145fb4ac authored by Jim Hill on 31 May 2015, 18:16:45 UTC, committed by Junio C Hamano on 10 August 2015, 19:51:13 UTC
The loop in strbuf_read() uses xread() repeatedly while extending the strbuf until the call returns zero. If the buffer is sufficiently large to begin with, this results in xread() returning the remainder of the file to the end (returning non-zero), the loop extending the strbuf, and then making another call to xread() to have it return zero. By using read_in_full(), we can tell when the read reached the end of file: when it returns less than was requested, it's eof. This way we can avoid an extra iteration that allocates an extra 8kB that is never used. Signed-off-by: Jim Hill <gjthill@gmail.com> Reviewed-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 282616c
pkt-line.c
#include "cache.h"
#include "pkt-line.h"
char packet_buffer[LARGE_PACKET_MAX];
static const char *packet_trace_prefix = "git";
static const char trace_key[] = "GIT_TRACE_PACKET";
void packet_trace_identity(const char *prog)
{
packet_trace_prefix = xstrdup(prog);
}
static void packet_trace(const char *buf, unsigned int len, int write)
{
int i;
struct strbuf out;
if (!trace_want(trace_key))
return;
/* +32 is just a guess for header + quoting */
strbuf_init(&out, len+32);
strbuf_addf(&out, "packet: %12s%c ",
packet_trace_prefix, write ? '>' : '<');
if ((len >= 4 && starts_with(buf, "PACK")) ||
(len >= 5 && starts_with(buf+1, "PACK"))) {
strbuf_addstr(&out, "PACK ...");
unsetenv(trace_key);
}
else {
/* XXX we should really handle printable utf8 */
for (i = 0; i < len; i++) {
/* suppress newlines */
if (buf[i] == '\n')
continue;
if (buf[i] >= 0x20 && buf[i] <= 0x7e)
strbuf_addch(&out, buf[i]);
else
strbuf_addf(&out, "\\%o", buf[i]);
}
}
strbuf_addch(&out, '\n');
trace_strbuf(trace_key, &out);
strbuf_release(&out);
}
/*
* If we buffered things up above (we don't, but we should),
* we'd flush it here
*/
void packet_flush(int fd)
{
packet_trace("0000", 4, 1);
write_or_die(fd, "0000", 4);
}
void packet_buf_flush(struct strbuf *buf)
{
packet_trace("0000", 4, 1);
strbuf_add(buf, "0000", 4);
}
#define hex(a) (hexchar[(a) & 15])
static char buffer[1000];
static unsigned format_packet(const char *fmt, va_list args)
{
static char hexchar[] = "0123456789abcdef";
unsigned n;
n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
if (n >= sizeof(buffer)-4)
die("protocol error: impossibly long line");
n += 4;
buffer[0] = hex(n >> 12);
buffer[1] = hex(n >> 8);
buffer[2] = hex(n >> 4);
buffer[3] = hex(n);
packet_trace(buffer+4, n-4, 1);
return n;
}
void packet_write(int fd, const char *fmt, ...)
{
va_list args;
unsigned n;
va_start(args, fmt);
n = format_packet(fmt, args);
va_end(args);
write_or_die(fd, buffer, n);
}
void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
{
va_list args;
unsigned n;
va_start(args, fmt);
n = format_packet(fmt, args);
va_end(args);
strbuf_add(buf, buffer, n);
}
static int get_packet_data(int fd, char **src_buf, size_t *src_size,
void *dst, unsigned size, int options)
{
ssize_t ret;
if (fd >= 0 && src_buf && *src_buf)
die("BUG: multiple sources given to packet_read");
/* Read up to "size" bytes from our source, whatever it is. */
if (src_buf && *src_buf) {
ret = size < *src_size ? size : *src_size;
memcpy(dst, *src_buf, ret);
*src_buf += ret;
*src_size -= ret;
} else {
ret = read_in_full(fd, dst, size);
if (ret < 0)
die_errno("read error");
}
/* And complain if we didn't get enough bytes to satisfy the read. */
if (ret < size) {
if (options & PACKET_READ_GENTLE_ON_EOF)
return -1;
die("The remote end hung up unexpectedly");
}
return ret;
}
static int packet_length(const char *linelen)
{
int n;
int len = 0;
for (n = 0; n < 4; n++) {
unsigned char c = linelen[n];
len <<= 4;
if (c >= '0' && c <= '9') {
len += c - '0';
continue;
}
if (c >= 'a' && c <= 'f') {
len += c - 'a' + 10;
continue;
}
if (c >= 'A' && c <= 'F') {
len += c - 'A' + 10;
continue;
}
return -1;
}
return len;
}
int packet_read(int fd, char **src_buf, size_t *src_len,
char *buffer, unsigned size, int options)
{
int len, ret;
char linelen[4];
ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
if (ret < 0)
return ret;
len = packet_length(linelen);
if (len < 0)
die("protocol error: bad line length character: %.4s", linelen);
if (!len) {
packet_trace("0000", 4, 0);
return 0;
}
len -= 4;
if (len >= size)
die("protocol error: bad line length %d", len);
ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
if (ret < 0)
return ret;
if ((options & PACKET_READ_CHOMP_NEWLINE) &&
len && buffer[len-1] == '\n')
len--;
buffer[len] = 0;
packet_trace(buffer, len, 0);
return len;
}
static char *packet_read_line_generic(int fd,
char **src, size_t *src_len,
int *dst_len)
{
int len = packet_read(fd, src, src_len,
packet_buffer, sizeof(packet_buffer),
PACKET_READ_CHOMP_NEWLINE);
if (dst_len)
*dst_len = len;
return len ? packet_buffer : NULL;
}
char *packet_read_line(int fd, int *len_p)
{
return packet_read_line_generic(fd, NULL, NULL, len_p);
}
char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
{
return packet_read_line_generic(-1, src, src_len, dst_len);
}
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