grep: add support for coloring with external greps

diff --git a/builtin-rev-list.c b/builtin-rev-list.c
index 436afa45f5b7569551aa8301aee8a0752009a900..40d5fcb6b0b26c76c271624408b531cc01e15f7b 100644 (file)
--- a/builtin-rev-list.c
+++ b/builtin-rev-list.c
@@ -574,6 +574,45 @@ static struct commit_list *find_bisection(struct commit_list *list,
        return best;
 }
 
+static inline int log2i(int n)
+{
+       int log2 = 0;
+
+       for (; n > 1; n >>= 1)
+               log2++;
+
+       return log2;
+}
+
+static inline int exp2i(int n)
+{
+       return 1 << n;
+}
+
+/*
+ * Estimate the number of bisect steps left (after the current step)
+ *
+ * For any x between 0 included and 2^n excluded, the probability for
+ * n - 1 steps left looks like:
+ *
+ * P(2^n + x) == (2^n - x) / (2^n + x)
+ *
+ * and P(2^n + x) < 0.5 means 2^n < 3x
+ */
+static int estimate_bisect_steps(int all)
+{
+       int n, x, e;
+
+       if (all < 3)
+               return 0;
+
+       n = log2i(all);
+       e = exp2i(n);
+       x = all - e;
+
+       return (e < 3 * x) ? n : n - 1;
+}
+
 int cmd_rev_list(int argc, const char **argv, const char *prefix)
 {
        struct commit_list *list;
@@ -688,12 +727,14 @@ int cmd_rev_list(int argc, const char **argv, const char *prefix)
                               "bisect_nr=%d\n"
                               "bisect_good=%d\n"
                               "bisect_bad=%d\n"
-                              "bisect_all=%d\n",
+                              "bisect_all=%d\n"
+                              "bisect_steps=%d\n",
                               hex,
                               cnt - 1,
                               all - reaches - 1,
                               reaches - 1,
-                              all);
+                              all,
+                              estimate_bisect_steps(all));
                        return 0;
                }
        }