Fix and improve t7004 (git-tag tests)

diff --git a/interpolate.c b/interpolate.c
index 5d9d1889f088c64131cd3c116e6a16876ce95db8..6ef53f246511a1943e375d5d5913a4ec52e2c663 100644 (file)
--- a/interpolate.c
+++ b/interpolate.c
@@ -2,8 +2,6 @@
  * Copyright 2006 Jon Loeliger
  */
 
-#include <string.h>
-
 #include "git-compat-util.h"
 #include "interpolate.h"
 
@@ -46,63 +44,61 @@ void interp_clear_table(struct interp *table, int ninterps)
  *        { "%%", "%"},
  *    }
  *
- * Returns 1 on a successful substitution pass that fits in result,
- * Returns 0 on a failed or overflowing substitution pass.
+ * Returns the length of the substituted string (not including the final \0).
+ * Like with snprintf, if the result is >= reslen, then it overflowed.
  */
 
-int interpolate(char *result, int reslen,
+unsigned long interpolate(char *result, unsigned long reslen,
                const char *orig,
                const struct interp *interps, int ninterps)
 {
        const char *src = orig;
        char *dest = result;
-       int newlen = 0;
-       char *name, *value;
-       int namelen, valuelen;
+       unsigned long newlen = 0;
+       const char *name, *value;
+       unsigned long namelen, valuelen;
        int i;
        char c;
 
-        memset(result, 0, reslen);
-
-       while ((c = *src) && newlen < reslen - 1) {
+       while ((c = *src)) {
                if (c == '%') {
                        /* Try to match an interpolation string. */
                        for (i = 0; i < ninterps; i++) {
                                name = interps[i].name;
                                namelen = strlen(name);
-                               if (strncmp(src, name, namelen) == 0) {
+                               if (strncmp(src, name, namelen) == 0)
                                        break;
-                               }
                        }
 
                        /* Check for valid interpolation. */
                        if (i < ninterps) {
                                value = interps[i].value;
-                               valuelen = strlen(value);
+                               if (!value) {
+                                       src += namelen;
+                                       continue;
+                               }
 
-                               if (newlen + valuelen < reslen - 1) {
+                               valuelen = strlen(value);
+                               if (newlen + valuelen < reslen) {
                                        /* Substitute. */
-                                       strncpy(dest, value, valuelen);
-                                       newlen += valuelen;
+                                       memcpy(dest, value, valuelen);
                                        dest += valuelen;
-                                       src += namelen;
-                               } else {
-                                       /* Something's not fitting. */
-                                       return 0;
                                }
-
-                       } else {
-                               /* Skip bogus interpolation. */
-                               *dest++ = *src++;
-                               newlen++;
+                               newlen += valuelen;
+                               src += namelen;
+                               continue;
                        }
-
-               } else {
-                       /* Straight copy one non-interpolation character. */
-                       *dest++ = *src++;
-                       newlen++;
                }
+               /* Straight copy one non-interpolation character. */
+               if (newlen + 1 < reslen)
+                       *dest++ = *src;
+               src++;
+               newlen++;
        }
 
-       return newlen < reslen - 1;
+       /* XXX: the previous loop always keep room for the ending NUL,
+          we just need to check if there was room for a NUL in the first place */
+       if (reslen > 0)
+               *dest = '\0';
+       return newlen;
 }