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![Karsten Blees](/assets/img/avatar_default.png)
The trace API currently rechecks the environment variable and reopens the trace file on every API call. This has the ugly side effect that errors (e.g. file cannot be opened, or the user specified a relative path) are also reported on every call. Performance can be improved by about factor three by remembering the environment state and keeping the file open. Replace the 'const char *key' parameter in the API with a pointer to a 'struct trace_key' that bundles the environment variable name with additional, trace-internal state. Change the call sites of these APIs to use a static 'struct trace_key' instead of a string constant. In trace.c::get_trace_fd(), save and reuse the file descriptor in 'struct trace_key'. Add a 'trace_disable()' API, so that packet_trace() can cleanly disable tracing when it encounters packed data (instead of using unsetenv()). Signed-off-by: Karsten Blees <blees@dcon.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
216 lines
4.5 KiB
C
216 lines
4.5 KiB
C
#include "cache.h"
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#include "pkt-line.h"
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char packet_buffer[LARGE_PACKET_MAX];
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static const char *packet_trace_prefix = "git";
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static struct trace_key trace_packet = TRACE_KEY_INIT(PACKET);
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void packet_trace_identity(const char *prog)
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{
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packet_trace_prefix = xstrdup(prog);
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}
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static void packet_trace(const char *buf, unsigned int len, int write)
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{
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int i;
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struct strbuf out;
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if (!trace_want(&trace_packet))
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return;
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/* +32 is just a guess for header + quoting */
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strbuf_init(&out, len+32);
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strbuf_addf(&out, "packet: %12s%c ",
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packet_trace_prefix, write ? '>' : '<');
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if ((len >= 4 && starts_with(buf, "PACK")) ||
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(len >= 5 && starts_with(buf+1, "PACK"))) {
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strbuf_addstr(&out, "PACK ...");
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trace_disable(&trace_packet);
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}
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else {
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/* XXX we should really handle printable utf8 */
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for (i = 0; i < len; i++) {
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/* suppress newlines */
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if (buf[i] == '\n')
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continue;
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if (buf[i] >= 0x20 && buf[i] <= 0x7e)
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strbuf_addch(&out, buf[i]);
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else
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strbuf_addf(&out, "\\%o", buf[i]);
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}
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}
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strbuf_addch(&out, '\n');
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trace_strbuf(&trace_packet, &out);
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strbuf_release(&out);
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}
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/*
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* If we buffered things up above (we don't, but we should),
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* we'd flush it here
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*/
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void packet_flush(int fd)
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{
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packet_trace("0000", 4, 1);
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write_or_die(fd, "0000", 4);
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}
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void packet_buf_flush(struct strbuf *buf)
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{
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packet_trace("0000", 4, 1);
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strbuf_add(buf, "0000", 4);
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}
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#define hex(a) (hexchar[(a) & 15])
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static char buffer[1000];
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static unsigned format_packet(const char *fmt, va_list args)
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{
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static char hexchar[] = "0123456789abcdef";
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unsigned n;
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n = vsnprintf(buffer + 4, sizeof(buffer) - 4, fmt, args);
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if (n >= sizeof(buffer)-4)
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die("protocol error: impossibly long line");
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n += 4;
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buffer[0] = hex(n >> 12);
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buffer[1] = hex(n >> 8);
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buffer[2] = hex(n >> 4);
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buffer[3] = hex(n);
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packet_trace(buffer+4, n-4, 1);
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return n;
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}
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void packet_write(int fd, const char *fmt, ...)
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{
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va_list args;
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unsigned n;
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va_start(args, fmt);
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n = format_packet(fmt, args);
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va_end(args);
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write_or_die(fd, buffer, n);
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}
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void packet_buf_write(struct strbuf *buf, const char *fmt, ...)
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{
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va_list args;
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unsigned n;
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va_start(args, fmt);
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n = format_packet(fmt, args);
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va_end(args);
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strbuf_add(buf, buffer, n);
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}
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static int get_packet_data(int fd, char **src_buf, size_t *src_size,
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void *dst, unsigned size, int options)
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{
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ssize_t ret;
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if (fd >= 0 && src_buf && *src_buf)
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die("BUG: multiple sources given to packet_read");
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/* Read up to "size" bytes from our source, whatever it is. */
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if (src_buf && *src_buf) {
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ret = size < *src_size ? size : *src_size;
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memcpy(dst, *src_buf, ret);
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*src_buf += ret;
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*src_size -= ret;
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} else {
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ret = read_in_full(fd, dst, size);
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if (ret < 0)
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die_errno("read error");
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}
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/* And complain if we didn't get enough bytes to satisfy the read. */
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if (ret < size) {
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if (options & PACKET_READ_GENTLE_ON_EOF)
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return -1;
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die("The remote end hung up unexpectedly");
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}
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return ret;
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}
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static int packet_length(const char *linelen)
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{
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int n;
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int len = 0;
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for (n = 0; n < 4; n++) {
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unsigned char c = linelen[n];
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len <<= 4;
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if (c >= '0' && c <= '9') {
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len += c - '0';
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continue;
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}
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if (c >= 'a' && c <= 'f') {
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len += c - 'a' + 10;
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continue;
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}
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if (c >= 'A' && c <= 'F') {
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len += c - 'A' + 10;
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continue;
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}
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return -1;
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}
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return len;
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}
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int packet_read(int fd, char **src_buf, size_t *src_len,
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char *buffer, unsigned size, int options)
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{
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int len, ret;
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char linelen[4];
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ret = get_packet_data(fd, src_buf, src_len, linelen, 4, options);
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if (ret < 0)
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return ret;
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len = packet_length(linelen);
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if (len < 0)
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die("protocol error: bad line length character: %.4s", linelen);
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if (!len) {
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packet_trace("0000", 4, 0);
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return 0;
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}
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len -= 4;
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if (len >= size)
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die("protocol error: bad line length %d", len);
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ret = get_packet_data(fd, src_buf, src_len, buffer, len, options);
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if (ret < 0)
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return ret;
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if ((options & PACKET_READ_CHOMP_NEWLINE) &&
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len && buffer[len-1] == '\n')
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len--;
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buffer[len] = 0;
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packet_trace(buffer, len, 0);
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return len;
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}
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static char *packet_read_line_generic(int fd,
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char **src, size_t *src_len,
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int *dst_len)
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{
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int len = packet_read(fd, src, src_len,
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packet_buffer, sizeof(packet_buffer),
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PACKET_READ_CHOMP_NEWLINE);
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if (dst_len)
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*dst_len = len;
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return len ? packet_buffer : NULL;
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}
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char *packet_read_line(int fd, int *len_p)
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{
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return packet_read_line_generic(fd, NULL, NULL, len_p);
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}
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char *packet_read_line_buf(char **src, size_t *src_len, int *dst_len)
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{
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return packet_read_line_generic(-1, src, src_len, dst_len);
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}
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