pack-refs: merge code from pack-refs.{c,h} into refs.{c,h}

pack-refs.c doesn't contain much code, and the code it does contain is
closely related to reference handling.  Moreover, there is some
duplication between pack_refs() and repack_without_ref().  Therefore,
merge pack-refs.c into refs.c and pack-refs.h into refs.h.

The code duplication will be addressed in future commits.

Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Makefile

@@ -644,7 +644,6 @@ LIB_H += notes-cache.h
 LIB_H += notes-merge.h
 LIB_H += notes.h
 LIB_H += object.h
-LIB_H += pack-refs.h
 LIB_H += pack-revindex.h
 LIB_H += pack.h
 LIB_H += parse-options.h
@@ -775,7 +774,6 @@ LIB_OBJS += notes-cache.o
 LIB_OBJS += notes-merge.o
 LIB_OBJS += object.o
 LIB_OBJS += pack-check.o
-LIB_OBJS += pack-refs.o
 LIB_OBJS += pack-revindex.o
 LIB_OBJS += pack-write.o
 LIB_OBJS += pager.o

builtin/clone.c

@@ -18,7 +18,6 @@
 #include "transport.h"
 #include "strbuf.h"
 #include "dir.h"
-#include "pack-refs.h"
 #include "sigchain.h"
 #include "branch.h"
 #include "remote.h"

builtin/pack-refs.c

@@ -1,6 +1,6 @@
 #include "builtin.h"
 #include "parse-options.h"
-#include "pack-refs.h"
+#include "refs.h"
 
 static char const * const pack_refs_usage[] = {
 	N_("git pack-refs [options]"),

refs.c

@@ -1984,6 +1984,150 @@ static void write_packed_entry(int fd, char *refname, unsigned char *sha1,
 	}
 }
 
+struct ref_to_prune {
+	struct ref_to_prune *next;
+	unsigned char sha1[20];
+	char name[FLEX_ARRAY];
+};
+
+struct pack_refs_cb_data {
+	unsigned int flags;
+	struct ref_to_prune *ref_to_prune;
+	FILE *refs_file;
+};
+
+static int do_not_prune(int flags)
+{
+	/* If it is already packed or if it is a symref,
+	 * do not prune it.
+	 */
+	return (flags & (REF_ISSYMREF|REF_ISPACKED));
+}
+
+static int pack_one_ref(const char *path, const unsigned char *sha1,
+			  int flags, void *cb_data)
+{
+	struct pack_refs_cb_data *cb = cb_data;
+	struct object *o;
+	int is_tag_ref;
+
+	/* Do not pack the symbolic refs */
+	if ((flags & REF_ISSYMREF))
+		return 0;
+	is_tag_ref = !prefixcmp(path, "refs/tags/");
+
+	/* ALWAYS pack refs that were already packed or are tags */
+	if (!(cb->flags & PACK_REFS_ALL) && !is_tag_ref && !(flags & REF_ISPACKED))
+		return 0;
+
+	fprintf(cb->refs_file, "%s %s\n", sha1_to_hex(sha1), path);
+
+	o = parse_object_or_die(sha1, path);
+	if (o->type == OBJ_TAG) {
+		o = deref_tag(o, path, 0);
+		if (o)
+			fprintf(cb->refs_file, "^%s\n",
+				sha1_to_hex(o->sha1));
+	}
+
+	if ((cb->flags & PACK_REFS_PRUNE) && !do_not_prune(flags)) {
+		int namelen = strlen(path) + 1;
+		struct ref_to_prune *n = xcalloc(1, sizeof(*n) + namelen);
+		hashcpy(n->sha1, sha1);
+		strcpy(n->name, path);
+		n->next = cb->ref_to_prune;
+		cb->ref_to_prune = n;
+	}
+	return 0;
+}
+
+/*
+ * Remove empty parents, but spare refs/ and immediate subdirs.
+ * Note: munges *name.
+ */
+static void try_remove_empty_parents(char *name)
+{
+	char *p, *q;
+	int i;
+	p = name;
+	for (i = 0; i < 2; i++) { /* refs/{heads,tags,...}/ */
+		while (*p && *p != '/')
+			p++;
+		/* tolerate duplicate slashes; see check_refname_format() */
+		while (*p == '/')
+			p++;
+	}
+	for (q = p; *q; q++)
+		;
+	while (1) {
+		while (q > p && *q != '/')
+			q--;
+		while (q > p && *(q-1) == '/')
+			q--;
+		if (q == p)
+			break;
+		*q = '\0';
+		if (rmdir(git_path("%s", name)))
+			break;
+	}
+}
+
+/* make sure nobody touched the ref, and unlink */
+static void prune_ref(struct ref_to_prune *r)
+{
+	struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1);
+
+	if (lock) {
+		unlink_or_warn(git_path("%s", r->name));
+		unlock_ref(lock);
+		try_remove_empty_parents(r->name);
+	}
+}
+
+static void prune_refs(struct ref_to_prune *r)
+{
+	while (r) {
+		prune_ref(r);
+		r = r->next;
+	}
+}
+
+static struct lock_file packed;
+
+int pack_refs(unsigned int flags)
+{
+	int fd;
+	struct pack_refs_cb_data cbdata;
+
+	memset(&cbdata, 0, sizeof(cbdata));
+	cbdata.flags = flags;
+
+	fd = hold_lock_file_for_update(&packed, git_path("packed-refs"),
+				       LOCK_DIE_ON_ERROR);
+	cbdata.refs_file = fdopen(fd, "w");
+	if (!cbdata.refs_file)
+		die_errno("unable to create ref-pack file structure");
+
+	/* perhaps other traits later as well */
+	fprintf(cbdata.refs_file, "# pack-refs with: peeled fully-peeled \n");
+
+	for_each_ref(pack_one_ref, &cbdata);
+	if (ferror(cbdata.refs_file))
+		die("failed to write ref-pack file");
+	if (fflush(cbdata.refs_file) || fsync(fd) || fclose(cbdata.refs_file))
+		die_errno("failed to write ref-pack file");
+	/*
+	 * Since the lock file was fdopen()'ed and then fclose()'ed above,
+	 * assign -1 to the lock file descriptor so that commit_lock_file()
+	 * won't try to close() it.
+	 */
+	packed.fd = -1;
+	if (commit_lock_file(&packed) < 0)
+		die_errno("unable to overwrite old ref-pack file");
+	prune_refs(cbdata.ref_to_prune);
+	return 0;
+}
+
 static int repack_ref_fn(struct ref_entry *entry, void *cb_data)
 {
 	int *fd = cb_data;

refs.h

@@ -72,6 +72,20 @@ extern void warn_dangling_symref(FILE *fp, const char *msg_fmt, const char *refn
  */
 extern void add_packed_ref(const char *refname, const unsigned char *sha1);
 
+/*
+ * Flags for controlling behaviour of pack_refs()
+ * PACK_REFS_PRUNE: Prune loose refs after packing
+ * PACK_REFS_ALL:   Pack _all_ refs, not just tags and already packed refs
+ */
+#define PACK_REFS_PRUNE 0x0001
+#define PACK_REFS_ALL   0x0002
+
+/*
+ * Write a packed-refs file for the current repository.
+ * flags: Combination of the above PACK_REFS_* flags.
+ */
+int pack_refs(unsigned int flags);
+
 extern int ref_exists(const char *);
 
 /*