t6022: New tests checking for unnecessary updates of files

diff --git a/pkt-line.c b/pkt-line.c
index b691abebd79b40f096b28b5dbcb433f01bc0e949..5a04984ea31744528de30269add2754ed2dcd105 100644 (file)
--- a/pkt-line.c
+++ b/pkt-line.c
@@ -1,6 +1,51 @@
 #include "cache.h"
 #include "pkt-line.h"
 
+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 && !prefixcmp(buf, "PACK")) ||
+           (len >= 5 && !prefixcmp(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);
+}
+
 /*
  * Write a packetized stream, where each line is preceded by
  * its length (including the header) as a 4-byte hex number.
@@ -39,20 +84,24 @@ ssize_t safe_write(int fd, const void *buf, ssize_t n)
  */
 void packet_flush(int fd)
 {
+       packet_trace("0000", 4, 1);
        safe_write(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])
-void packet_write(int fd, const char *fmt, ...)
+static char buffer[1000];
+static unsigned format_packet(const char *fmt, va_list args)
 {
-       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;
@@ -60,9 +109,32 @@ void packet_write(int fd, const char *fmt, ...)
        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);
        safe_write(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 void safe_read(int fd, void *buffer, unsigned size)
 {
        ssize_t ret = read_in_full(fd, buffer, size);
@@ -72,15 +144,11 @@ static void safe_read(int fd, void *buffer, unsigned size)
                die("The remote end hung up unexpectedly");
 }
 
-int packet_read_line(int fd, char *buffer, unsigned size)
+static int packet_length(const char *linelen)
 {
        int n;
-       unsigned len;
-       char linelen[4];
-
-       safe_read(fd, linelen, 4);
+       int len = 0;
 
-       len = 0;
        for (n = 0; n < 4; n++) {
                unsigned char c = linelen[n];
                len <<= 4;
@@ -96,14 +164,59 @@ int packet_read_line(int fd, char *buffer, unsigned size)
                        len += c - 'A' + 10;
                        continue;
                }
-               die("protocol error: bad line length character");
+               return -1;
        }
-       if (!len)
+       return len;
+}
+
+int packet_read_line(int fd, char *buffer, unsigned size)
+{
+       int len;
+       char linelen[4];
+
+       safe_read(fd, linelen, 4);
+       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);
        safe_read(fd, buffer, len);
        buffer[len] = 0;
+       packet_trace(buffer, len, 0);
+       return len;
+}
+
+int packet_get_line(struct strbuf *out,
+       char **src_buf, size_t *src_len)
+{
+       int len;
+
+       if (*src_len < 4)
+               return -1;
+       len = packet_length(*src_buf);
+       if (len < 0)
+               return -1;
+       if (!len) {
+               *src_buf += 4;
+               *src_len -= 4;
+               packet_trace("0000", 4, 0);
+               return 0;
+       }
+       if (*src_len < len)
+               return -2;
+
+       *src_buf += 4;
+       *src_len -= 4;
+       len -= 4;
+
+       strbuf_add(out, *src_buf, len);
+       *src_buf += len;
+       *src_len -= len;
+       packet_trace(out->buf, out->len, 0);
        return len;
 }