Merge branch 'lh/merge'

diff --git a/builtin-gc.c b/builtin-gc.c
index 939748261041049f31d62935ec08f062bdfa6e79..23ad2b6a21a81f469e813173ba04d626949e972f 100644 (file)
--- a/builtin-gc.c
+++ b/builtin-gc.c
@@ -20,6 +20,8 @@ static const char builtin_gc_usage[] = "git-gc [--prune] [--aggressive]";
 
 static int pack_refs = 1;
 static int aggressive_window = -1;
+static int gc_auto_threshold = 6700;
+static int gc_auto_pack_limit = 20;
 
 #define MAX_ADD 10
 static const char *argv_pack_refs[] = {"pack-refs", "--all", "--prune", NULL};
@@ -41,6 +43,14 @@ static int gc_config(const char *var, const char *value)
                aggressive_window = git_config_int(var, value);
                return 0;
        }
+       if (!strcmp(var, "gc.auto")) {
+               gc_auto_threshold = git_config_int(var, value);
+               return 0;
+       }
+       if (!strcmp(var, "gc.autopacklimit")) {
+               gc_auto_pack_limit = git_config_int(var, value);
+               return 0;
+       }
        return git_default_config(var, value);
 }
 
@@ -57,10 +67,113 @@ static void append_option(const char **cmd, const char *opt, int max_length)
        cmd[i] = NULL;
 }
 
+static int too_many_loose_objects(void)
+{
+       /*
+        * Quickly check if a "gc" is needed, by estimating how
+        * many loose objects there are.  Because SHA-1 is evenly
+        * distributed, we can check only one and get a reasonable
+        * estimate.
+        */
+       char path[PATH_MAX];
+       const char *objdir = get_object_directory();
+       DIR *dir;
+       struct dirent *ent;
+       int auto_threshold;
+       int num_loose = 0;
+       int needed = 0;
+
+       if (gc_auto_threshold <= 0)
+               return 0;
+
+       if (sizeof(path) <= snprintf(path, sizeof(path), "%s/17", objdir)) {
+               warning("insanely long object directory %.*s", 50, objdir);
+               return 0;
+       }
+       dir = opendir(path);
+       if (!dir)
+               return 0;
+
+       auto_threshold = (gc_auto_threshold + 255) / 256;
+       while ((ent = readdir(dir)) != NULL) {
+               if (strspn(ent->d_name, "0123456789abcdef") != 38 ||
+                   ent->d_name[38] != '\0')
+                       continue;
+               if (++num_loose > auto_threshold) {
+                       needed = 1;
+                       break;
+               }
+       }
+       closedir(dir);
+       return needed;
+}
+
+static int too_many_packs(void)
+{
+       struct packed_git *p;
+       int cnt;
+
+       if (gc_auto_pack_limit <= 0)
+               return 0;
+
+       prepare_packed_git();
+       for (cnt = 0, p = packed_git; p; p = p->next) {
+               char path[PATH_MAX];
+               size_t len;
+               int keep;
+
+               if (!p->pack_local)
+                       continue;
+               len = strlen(p->pack_name);
+               if (PATH_MAX <= len + 1)
+                       continue; /* oops, give up */
+               memcpy(path, p->pack_name, len-5);
+               memcpy(path + len - 5, ".keep", 6);
+               keep = access(p->pack_name, F_OK) && (errno == ENOENT);
+               if (keep)
+                       continue;
+               /*
+                * Perhaps check the size of the pack and count only
+                * very small ones here?
+                */
+               cnt++;
+       }
+       return gc_auto_pack_limit <= cnt;
+}
+
+static int need_to_gc(void)
+{
+       int ac = 0;
+
+       /*
+        * Setting gc.auto and gc.autopacklimit to 0 or negative can
+        * disable the automatic gc.
+        */
+       if (gc_auto_threshold <= 0 && gc_auto_pack_limit <= 0)
+               return 0;
+
+       /*
+        * If there are too many loose objects, but not too many
+        * packs, we run "repack -d -l".  If there are too many packs,
+        * we run "repack -A -d -l".  Otherwise we tell the caller
+        * there is no need.
+        */
+       argv_repack[ac++] = "repack";
+       if (too_many_packs())
+               argv_repack[ac++] = "-A";
+       else if (!too_many_loose_objects())
+               return 0;
+       argv_repack[ac++] = "-d";
+       argv_repack[ac++] = "-l";
+       argv_repack[ac++] = NULL;
+       return 1;
+}
+
 int cmd_gc(int argc, const char **argv, const char *prefix)
 {
        int i;
        int prune = 0;
+       int auto_gc = 0;
        char buf[80];
 
        git_config(gc_config);
@@ -82,12 +195,24 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
                        }
                        continue;
                }
-               /* perhaps other parameters later... */
+               if (!strcmp(arg, "--auto")) {
+                       auto_gc = 1;
+                       continue;
+               }
                break;
        }
        if (i != argc)
                usage(builtin_gc_usage);
 
+       if (auto_gc) {
+               /*
+                * Auto-gc should be least intrusive as possible.
+                */
+               prune = 0;
+               if (!need_to_gc())
+                       return 0;
+       }
+
        if (pack_refs && run_command_v_opt(argv_pack_refs, RUN_GIT_CMD))
                return error(FAILED_RUN, argv_pack_refs[0]);
 
@@ -103,5 +228,9 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
        if (run_command_v_opt(argv_rerere, RUN_GIT_CMD))
                return error(FAILED_RUN, argv_rerere[0]);
 
+       if (auto_gc && too_many_loose_objects())
+               warning("There are too many unreachable loose objects; "
+                       "run 'git prune' to remove them.");
+
        return 0;
 }