mirror of
https://github.com/git/git
synced 2024-08-25 10:45:59 +00:00
115 lines
2.4 KiB
C
115 lines
2.4 KiB
C
#include "cache.h"
|
|
#include "pkt-line.h"
|
|
|
|
/*
|
|
* Write a packetized stream, where each line is preceded by
|
|
* its length (including the header) as a 4-byte hex number.
|
|
* A length of 'zero' means end of stream (and a length of 1-3
|
|
* would be an error).
|
|
*
|
|
* This is all pretty stupid, but we use this packetized line
|
|
* format to make a streaming format possible without ever
|
|
* over-running the read buffers. That way we'll never read
|
|
* into what might be the pack data (which should go to another
|
|
* process entirely).
|
|
*
|
|
* The writing side could use stdio, but since the reading
|
|
* side can't, we stay with pure read/write interfaces.
|
|
*/
|
|
ssize_t safe_write(int fd, const void *buf, ssize_t n)
|
|
{
|
|
ssize_t nn = n;
|
|
while (n) {
|
|
int ret = xwrite(fd, buf, n);
|
|
if (ret > 0) {
|
|
buf = (char *) buf + ret;
|
|
n -= ret;
|
|
continue;
|
|
}
|
|
if (!ret)
|
|
die("write error (disk full?)");
|
|
die("write error (%s)", strerror(errno));
|
|
}
|
|
return nn;
|
|
}
|
|
|
|
/*
|
|
* If we buffered things up above (we don't, but we should),
|
|
* we'd flush it here
|
|
*/
|
|
void packet_flush(int fd)
|
|
{
|
|
safe_write(fd, "0000", 4);
|
|
}
|
|
|
|
#define hex(a) (hexchar[(a) & 15])
|
|
void packet_write(int fd, const char *fmt, ...)
|
|
{
|
|
static char buffer[1000];
|
|
static char hexchar[] = "0123456789abcdef";
|
|
va_list args;
|
|
unsigned n;
|
|
|
|
va_start(args, fmt);
|
|
n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
|
|
va_end(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);
|
|
safe_write(fd, buffer, n);
|
|
}
|
|
|
|
static void safe_read(int fd, void *buffer, unsigned size)
|
|
{
|
|
int n = 0;
|
|
|
|
while (n < size) {
|
|
int ret = xread(fd, (char *) buffer + n, size - n);
|
|
if (ret < 0)
|
|
die("read error (%s)", strerror(errno));
|
|
if (!ret)
|
|
die("unexpected EOF");
|
|
n += ret;
|
|
}
|
|
}
|
|
|
|
int packet_read_line(int fd, char *buffer, unsigned size)
|
|
{
|
|
int n;
|
|
unsigned len;
|
|
char linelen[4];
|
|
|
|
safe_read(fd, linelen, 4);
|
|
|
|
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;
|
|
}
|
|
die("protocol error: bad line length character");
|
|
}
|
|
if (!len)
|
|
return 0;
|
|
len -= 4;
|
|
if (len >= size)
|
|
die("protocol error: bad line length %d", len);
|
|
safe_read(fd, buffer, len);
|
|
buffer[len] = 0;
|
|
return len;
|
|
}
|