[PATCH] Add --no-reuse-delta option to git-gc

[Theodore Ts'o <tytso@mit.edu>]

This allows the user to regenerate the deltas in packs while doing
a git-gc.  The user could just run git-repack -a -d -f -l after
running git-gc, but then the first git-repack run by git-gc is
a bit of waste.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
---
 Documentation/git-gc.txt |    7 ++++++-
 builtin-gc.c             |   24 ++++++++++++++++++++++--
 2 files changed, 28 insertions(+), 3 deletions(-)

diff --git a/Documentation/git-gc.txt b/Documentation/git-gc.txt
index bc16584..0493d06 100644
--- a/Documentation/git-gc.txt
+++ b/Documentation/git-gc.txt
@@ -8,7 +8,7 @@ git-gc - Cleanup unnecessary files and optimize the local repository
 
 SYNOPSIS
 --------
-'git-gc' [--prune]
+'git-gc' [--prune] [--no-reuse-delta]
 
 DESCRIPTION
 -----------
@@ -35,6 +35,11 @@ OPTIONS
 	repository at the same time (e.g. never use this option
 	in a cron script).
 
+--no-reuse-delta::
+	This causes deltas in existing packs to be recalculated instead
+	of reusing the existing deltas.  This can save disk space at
+	the cost of taking more time to recalculate them from scratch.
+
 
 Configuration
 -------------
diff --git a/builtin-gc.c b/builtin-gc.c
index 3b1f8c2..5cb7ffd 100644
--- a/builtin-gc.c
+++ b/builtin-gc.c
@@ -15,13 +15,14 @@
 
 #define FAILED_RUN "failed to run %s"
 
-static const char builtin_gc_usage[] = "git-gc [--prune]";
+static const char builtin_gc_usage[] = "git-gc [--prune] [--no-reuse-delta]";
 
 static int pack_refs = -1;
 
+#define MAX_ADD 10
 static const char *argv_pack_refs[] = {"pack-refs", "--prune", NULL};
 static const char *argv_reflog[] = {"reflog", "expire", "--all", NULL};
-static const char *argv_repack[] = {"repack", "-a", "-d", "-l", NULL};
+static const char *argv_repack[MAX_ADD] = {"repack", "-a", "-d", "-l", NULL};
 static const char *argv_prune[] = {"prune", NULL};
 static const char *argv_rerere[] = {"rerere", "gc", NULL};
 
@@ -37,6 +38,21 @@ static int gc_config(const char *var, const char *value)
 	return git_default_config(var, value);
 }
 
+static append_option(const char **cmd, const char *opt, int max_length)
+{
+	int	i;
+
+	for (i=0; cmd[i]; i++)
+		;
+
+	if (i+2 >= max_length) {
+		fprintf(stderr, "Too many options specified\n");
+		exit(1);
+	}
+	cmd[i++] = opt;
+	cmd[i] = 0;
+}
+
 int cmd_gc(int argc, const char **argv, const char *prefix)
 {
 	int i;
@@ -53,6 +69,10 @@ int cmd_gc(int argc, const char **argv, const char *prefix)
 			prune = 1;
 			continue;
 		}
+		if (!strcmp(arg, "--no-reuse-delta")) {
+			append_option(argv_repack, "-f", MAX_ADD);
+			continue;
+		}
 		/* perhaps other parameters later... */
 		break;
 	}
-- 
1.5.2.rc2.22.ga39d