git/builtin/reflog.c
Martin Ågren 7199203937 object_array: add and use object_array_pop()
In a couple of places, we pop objects off an object array `foo` by
decreasing `foo.nr`. We access `foo.nr` in many places, but most if not
all other times we do so read-only, e.g., as we iterate over the array.
But when we change `foo.nr` behind the array's back, it feels a bit
nasty and looks like it might leak memory.

Leaks happen if the popped element has an allocated `name` or `path`.
At the moment, that is not the case. Still, 1) the object array might
gain more fields that want to be freed, 2) a code path where we pop
might start using names or paths, 3) one of these code paths might be
copied to somewhere where we do, and 4) using a dedicated function for
popping is conceptually cleaner.

Introduce and use `object_array_pop()` instead. Release memory in the
new function. Document that popping an object leaves the associated
elements in limbo.

The converted places were identified by grepping for "\.nr\>" and
looking for "--".

Make the new function return NULL on an empty array. This is consistent
with `pop_commit()` and allows the following:

	while ((o = object_array_pop(&foo)) != NULL) {
		// do something
	}

But as noted above, we don't need to go out of our way to avoid reading
`foo.nr`. This is probably more readable:

	while (foo.nr) {
		... o = object_array_pop(&foo);
		// do something
	}

The name of `object_array_pop()` does not quite align with
`add_object_array()`. That is unfortunate. On the other hand, it matches
`object_array_clear()`. Arguably it's `add_...` that is the odd one out,
since it reads like it's used to "add" an "object array". For that
reason, side with `object_array_clear()`.

Signed-off-by: Martin Ågren <martin.agren@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2017-09-24 10:06:04 +09:00

752 lines
19 KiB
C

#include "builtin.h"
#include "config.h"
#include "lockfile.h"
#include "commit.h"
#include "refs.h"
#include "dir.h"
#include "tree-walk.h"
#include "diff.h"
#include "revision.h"
#include "reachable.h"
/* NEEDSWORK: switch to using parse_options */
static const char reflog_expire_usage[] =
"git reflog expire [--expire=<time>] [--expire-unreachable=<time>] [--rewrite] [--updateref] [--stale-fix] [--dry-run | -n] [--verbose] [--all] <refs>...";
static const char reflog_delete_usage[] =
"git reflog delete [--rewrite] [--updateref] [--dry-run | -n] [--verbose] <refs>...";
static const char reflog_exists_usage[] =
"git reflog exists <ref>";
static timestamp_t default_reflog_expire;
static timestamp_t default_reflog_expire_unreachable;
struct cmd_reflog_expire_cb {
struct rev_info revs;
int stalefix;
timestamp_t expire_total;
timestamp_t expire_unreachable;
int recno;
};
struct expire_reflog_policy_cb {
enum {
UE_NORMAL,
UE_ALWAYS,
UE_HEAD
} unreachable_expire_kind;
struct commit_list *mark_list;
unsigned long mark_limit;
struct cmd_reflog_expire_cb cmd;
struct commit *tip_commit;
struct commit_list *tips;
};
struct collected_reflog {
unsigned char sha1[20];
char reflog[FLEX_ARRAY];
};
struct collect_reflog_cb {
struct collected_reflog **e;
int alloc;
int nr;
};
#define INCOMPLETE (1u<<10)
#define STUDYING (1u<<11)
#define REACHABLE (1u<<12)
static int tree_is_complete(const struct object_id *oid)
{
struct tree_desc desc;
struct name_entry entry;
int complete;
struct tree *tree;
tree = lookup_tree(oid);
if (!tree)
return 0;
if (tree->object.flags & SEEN)
return 1;
if (tree->object.flags & INCOMPLETE)
return 0;
if (!tree->buffer) {
enum object_type type;
unsigned long size;
void *data = read_sha1_file(oid->hash, &type, &size);
if (!data) {
tree->object.flags |= INCOMPLETE;
return 0;
}
tree->buffer = data;
tree->size = size;
}
init_tree_desc(&desc, tree->buffer, tree->size);
complete = 1;
while (tree_entry(&desc, &entry)) {
if (!has_sha1_file(entry.oid->hash) ||
(S_ISDIR(entry.mode) && !tree_is_complete(entry.oid))) {
tree->object.flags |= INCOMPLETE;
complete = 0;
}
}
free_tree_buffer(tree);
if (complete)
tree->object.flags |= SEEN;
return complete;
}
static int commit_is_complete(struct commit *commit)
{
struct object_array study;
struct object_array found;
int is_incomplete = 0;
int i;
/* early return */
if (commit->object.flags & SEEN)
return 1;
if (commit->object.flags & INCOMPLETE)
return 0;
/*
* Find all commits that are reachable and are not marked as
* SEEN. Then make sure the trees and blobs contained are
* complete. After that, mark these commits also as SEEN.
* If some of the objects that are needed to complete this
* commit are missing, mark this commit as INCOMPLETE.
*/
memset(&study, 0, sizeof(study));
memset(&found, 0, sizeof(found));
add_object_array(&commit->object, NULL, &study);
add_object_array(&commit->object, NULL, &found);
commit->object.flags |= STUDYING;
while (study.nr) {
struct commit *c;
struct commit_list *parent;
c = (struct commit *)object_array_pop(&study);
if (!c->object.parsed && !parse_object(&c->object.oid))
c->object.flags |= INCOMPLETE;
if (c->object.flags & INCOMPLETE) {
is_incomplete = 1;
break;
}
else if (c->object.flags & SEEN)
continue;
for (parent = c->parents; parent; parent = parent->next) {
struct commit *p = parent->item;
if (p->object.flags & STUDYING)
continue;
p->object.flags |= STUDYING;
add_object_array(&p->object, NULL, &study);
add_object_array(&p->object, NULL, &found);
}
}
if (!is_incomplete) {
/*
* make sure all commits in "found" array have all the
* necessary objects.
*/
for (i = 0; i < found.nr; i++) {
struct commit *c =
(struct commit *)found.objects[i].item;
if (!tree_is_complete(&c->tree->object.oid)) {
is_incomplete = 1;
c->object.flags |= INCOMPLETE;
}
}
if (!is_incomplete) {
/* mark all found commits as complete, iow SEEN */
for (i = 0; i < found.nr; i++)
found.objects[i].item->flags |= SEEN;
}
}
/* clear flags from the objects we traversed */
for (i = 0; i < found.nr; i++)
found.objects[i].item->flags &= ~STUDYING;
if (is_incomplete)
commit->object.flags |= INCOMPLETE;
else {
/*
* If we come here, we have (1) traversed the ancestry chain
* from the "commit" until we reach SEEN commits (which are
* known to be complete), and (2) made sure that the commits
* encountered during the above traversal refer to trees that
* are complete. Which means that we know *all* the commits
* we have seen during this process are complete.
*/
for (i = 0; i < found.nr; i++)
found.objects[i].item->flags |= SEEN;
}
/* free object arrays */
object_array_clear(&study);
object_array_clear(&found);
return !is_incomplete;
}
static int keep_entry(struct commit **it, struct object_id *oid)
{
struct commit *commit;
if (is_null_oid(oid))
return 1;
commit = lookup_commit_reference_gently(oid, 1);
if (!commit)
return 0;
/*
* Make sure everything in this commit exists.
*
* We have walked all the objects reachable from the refs
* and cache earlier. The commits reachable by this commit
* must meet SEEN commits -- and then we should mark them as
* SEEN as well.
*/
if (!commit_is_complete(commit))
return 0;
*it = commit;
return 1;
}
/*
* Starting from commits in the cb->mark_list, mark commits that are
* reachable from them. Stop the traversal at commits older than
* the expire_limit and queue them back, so that the caller can call
* us again to restart the traversal with longer expire_limit.
*/
static void mark_reachable(struct expire_reflog_policy_cb *cb)
{
struct commit_list *pending;
timestamp_t expire_limit = cb->mark_limit;
struct commit_list *leftover = NULL;
for (pending = cb->mark_list; pending; pending = pending->next)
pending->item->object.flags &= ~REACHABLE;
pending = cb->mark_list;
while (pending) {
struct commit_list *parent;
struct commit *commit = pop_commit(&pending);
if (commit->object.flags & REACHABLE)
continue;
if (parse_commit(commit))
continue;
commit->object.flags |= REACHABLE;
if (commit->date < expire_limit) {
commit_list_insert(commit, &leftover);
continue;
}
commit->object.flags |= REACHABLE;
parent = commit->parents;
while (parent) {
commit = parent->item;
parent = parent->next;
if (commit->object.flags & REACHABLE)
continue;
commit_list_insert(commit, &pending);
}
}
cb->mark_list = leftover;
}
static int unreachable(struct expire_reflog_policy_cb *cb, struct commit *commit, struct object_id *oid)
{
/*
* We may or may not have the commit yet - if not, look it
* up using the supplied sha1.
*/
if (!commit) {
if (is_null_oid(oid))
return 0;
commit = lookup_commit_reference_gently(oid, 1);
/* Not a commit -- keep it */
if (!commit)
return 0;
}
/* Reachable from the current ref? Don't prune. */
if (commit->object.flags & REACHABLE)
return 0;
if (cb->mark_list && cb->mark_limit) {
cb->mark_limit = 0; /* dig down to the root */
mark_reachable(cb);
}
return !(commit->object.flags & REACHABLE);
}
/*
* Return true iff the specified reflog entry should be expired.
*/
static int should_expire_reflog_ent(struct object_id *ooid, struct object_id *noid,
const char *email, timestamp_t timestamp, int tz,
const char *message, void *cb_data)
{
struct expire_reflog_policy_cb *cb = cb_data;
struct commit *old, *new;
if (timestamp < cb->cmd.expire_total)
return 1;
old = new = NULL;
if (cb->cmd.stalefix &&
(!keep_entry(&old, ooid) || !keep_entry(&new, noid)))
return 1;
if (timestamp < cb->cmd.expire_unreachable) {
if (cb->unreachable_expire_kind == UE_ALWAYS)
return 1;
if (unreachable(cb, old, ooid) || unreachable(cb, new, noid))
return 1;
}
if (cb->cmd.recno && --(cb->cmd.recno) == 0)
return 1;
return 0;
}
static int push_tip_to_list(const char *refname, const struct object_id *oid,
int flags, void *cb_data)
{
struct commit_list **list = cb_data;
struct commit *tip_commit;
if (flags & REF_ISSYMREF)
return 0;
tip_commit = lookup_commit_reference_gently(oid, 1);
if (!tip_commit)
return 0;
commit_list_insert(tip_commit, list);
return 0;
}
static void reflog_expiry_prepare(const char *refname,
const struct object_id *oid,
void *cb_data)
{
struct expire_reflog_policy_cb *cb = cb_data;
if (!cb->cmd.expire_unreachable || !strcmp(refname, "HEAD")) {
cb->tip_commit = NULL;
cb->unreachable_expire_kind = UE_HEAD;
} else {
cb->tip_commit = lookup_commit_reference_gently(oid, 1);
if (!cb->tip_commit)
cb->unreachable_expire_kind = UE_ALWAYS;
else
cb->unreachable_expire_kind = UE_NORMAL;
}
if (cb->cmd.expire_unreachable <= cb->cmd.expire_total)
cb->unreachable_expire_kind = UE_ALWAYS;
cb->mark_list = NULL;
cb->tips = NULL;
if (cb->unreachable_expire_kind != UE_ALWAYS) {
if (cb->unreachable_expire_kind == UE_HEAD) {
struct commit_list *elem;
for_each_ref(push_tip_to_list, &cb->tips);
for (elem = cb->tips; elem; elem = elem->next)
commit_list_insert(elem->item, &cb->mark_list);
} else {
commit_list_insert(cb->tip_commit, &cb->mark_list);
}
cb->mark_limit = cb->cmd.expire_total;
mark_reachable(cb);
}
}
static void reflog_expiry_cleanup(void *cb_data)
{
struct expire_reflog_policy_cb *cb = cb_data;
if (cb->unreachable_expire_kind != UE_ALWAYS) {
if (cb->unreachable_expire_kind == UE_HEAD) {
struct commit_list *elem;
for (elem = cb->tips; elem; elem = elem->next)
clear_commit_marks(elem->item, REACHABLE);
free_commit_list(cb->tips);
} else {
clear_commit_marks(cb->tip_commit, REACHABLE);
}
}
}
static int collect_reflog(const char *ref, const struct object_id *oid, int unused, void *cb_data)
{
struct collected_reflog *e;
struct collect_reflog_cb *cb = cb_data;
FLEX_ALLOC_STR(e, reflog, ref);
hashcpy(e->sha1, oid->hash);
ALLOC_GROW(cb->e, cb->nr + 1, cb->alloc);
cb->e[cb->nr++] = e;
return 0;
}
static struct reflog_expire_cfg {
struct reflog_expire_cfg *next;
timestamp_t expire_total;
timestamp_t expire_unreachable;
char pattern[FLEX_ARRAY];
} *reflog_expire_cfg, **reflog_expire_cfg_tail;
static struct reflog_expire_cfg *find_cfg_ent(const char *pattern, size_t len)
{
struct reflog_expire_cfg *ent;
if (!reflog_expire_cfg_tail)
reflog_expire_cfg_tail = &reflog_expire_cfg;
for (ent = reflog_expire_cfg; ent; ent = ent->next)
if (!strncmp(ent->pattern, pattern, len) &&
ent->pattern[len] == '\0')
return ent;
FLEX_ALLOC_MEM(ent, pattern, pattern, len);
*reflog_expire_cfg_tail = ent;
reflog_expire_cfg_tail = &(ent->next);
return ent;
}
static int parse_expire_cfg_value(const char *var, const char *value, timestamp_t *expire)
{
if (!value)
return config_error_nonbool(var);
if (parse_expiry_date(value, expire))
return error(_("'%s' for '%s' is not a valid timestamp"),
value, var);
return 0;
}
/* expiry timer slot */
#define EXPIRE_TOTAL 01
#define EXPIRE_UNREACH 02
static int reflog_expire_config(const char *var, const char *value, void *cb)
{
const char *pattern, *key;
int pattern_len;
timestamp_t expire;
int slot;
struct reflog_expire_cfg *ent;
if (parse_config_key(var, "gc", &pattern, &pattern_len, &key) < 0)
return git_default_config(var, value, cb);
if (!strcmp(key, "reflogexpire")) {
slot = EXPIRE_TOTAL;
if (parse_expire_cfg_value(var, value, &expire))
return -1;
} else if (!strcmp(key, "reflogexpireunreachable")) {
slot = EXPIRE_UNREACH;
if (parse_expire_cfg_value(var, value, &expire))
return -1;
} else
return git_default_config(var, value, cb);
if (!pattern) {
switch (slot) {
case EXPIRE_TOTAL:
default_reflog_expire = expire;
break;
case EXPIRE_UNREACH:
default_reflog_expire_unreachable = expire;
break;
}
return 0;
}
ent = find_cfg_ent(pattern, pattern_len);
if (!ent)
return -1;
switch (slot) {
case EXPIRE_TOTAL:
ent->expire_total = expire;
break;
case EXPIRE_UNREACH:
ent->expire_unreachable = expire;
break;
}
return 0;
}
static void set_reflog_expiry_param(struct cmd_reflog_expire_cb *cb, int slot, const char *ref)
{
struct reflog_expire_cfg *ent;
if (slot == (EXPIRE_TOTAL|EXPIRE_UNREACH))
return; /* both given explicitly -- nothing to tweak */
for (ent = reflog_expire_cfg; ent; ent = ent->next) {
if (!wildmatch(ent->pattern, ref, 0)) {
if (!(slot & EXPIRE_TOTAL))
cb->expire_total = ent->expire_total;
if (!(slot & EXPIRE_UNREACH))
cb->expire_unreachable = ent->expire_unreachable;
return;
}
}
/*
* If unconfigured, make stash never expire
*/
if (!strcmp(ref, "refs/stash")) {
if (!(slot & EXPIRE_TOTAL))
cb->expire_total = 0;
if (!(slot & EXPIRE_UNREACH))
cb->expire_unreachable = 0;
return;
}
/* Nothing matched -- use the default value */
if (!(slot & EXPIRE_TOTAL))
cb->expire_total = default_reflog_expire;
if (!(slot & EXPIRE_UNREACH))
cb->expire_unreachable = default_reflog_expire_unreachable;
}
static int cmd_reflog_expire(int argc, const char **argv, const char *prefix)
{
struct expire_reflog_policy_cb cb;
timestamp_t now = time(NULL);
int i, status, do_all;
int explicit_expiry = 0;
unsigned int flags = 0;
default_reflog_expire_unreachable = now - 30 * 24 * 3600;
default_reflog_expire = now - 90 * 24 * 3600;
git_config(reflog_expire_config, NULL);
save_commit_buffer = 0;
do_all = status = 0;
memset(&cb, 0, sizeof(cb));
cb.cmd.expire_total = default_reflog_expire;
cb.cmd.expire_unreachable = default_reflog_expire_unreachable;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
flags |= EXPIRE_REFLOGS_DRY_RUN;
else if (starts_with(arg, "--expire=")) {
if (parse_expiry_date(arg + 9, &cb.cmd.expire_total))
die(_("'%s' is not a valid timestamp"), arg);
explicit_expiry |= EXPIRE_TOTAL;
}
else if (starts_with(arg, "--expire-unreachable=")) {
if (parse_expiry_date(arg + 21, &cb.cmd.expire_unreachable))
die(_("'%s' is not a valid timestamp"), arg);
explicit_expiry |= EXPIRE_UNREACH;
}
else if (!strcmp(arg, "--stale-fix"))
cb.cmd.stalefix = 1;
else if (!strcmp(arg, "--rewrite"))
flags |= EXPIRE_REFLOGS_REWRITE;
else if (!strcmp(arg, "--updateref"))
flags |= EXPIRE_REFLOGS_UPDATE_REF;
else if (!strcmp(arg, "--all"))
do_all = 1;
else if (!strcmp(arg, "--verbose"))
flags |= EXPIRE_REFLOGS_VERBOSE;
else if (!strcmp(arg, "--")) {
i++;
break;
}
else if (arg[0] == '-')
usage(reflog_expire_usage);
else
break;
}
/*
* We can trust the commits and objects reachable from refs
* even in older repository. We cannot trust what's reachable
* from reflog if the repository was pruned with older git.
*/
if (cb.cmd.stalefix) {
init_revisions(&cb.cmd.revs, prefix);
if (flags & EXPIRE_REFLOGS_VERBOSE)
printf("Marking reachable objects...");
mark_reachable_objects(&cb.cmd.revs, 0, 0, NULL);
if (flags & EXPIRE_REFLOGS_VERBOSE)
putchar('\n');
}
if (do_all) {
struct collect_reflog_cb collected;
int i;
memset(&collected, 0, sizeof(collected));
for_each_reflog(collect_reflog, &collected);
for (i = 0; i < collected.nr; i++) {
struct collected_reflog *e = collected.e[i];
set_reflog_expiry_param(&cb.cmd, explicit_expiry, e->reflog);
status |= reflog_expire(e->reflog, e->sha1, flags,
reflog_expiry_prepare,
should_expire_reflog_ent,
reflog_expiry_cleanup,
&cb);
free(e);
}
free(collected.e);
}
for (; i < argc; i++) {
char *ref;
unsigned char sha1[20];
if (!dwim_log(argv[i], strlen(argv[i]), sha1, &ref)) {
status |= error("%s points nowhere!", argv[i]);
continue;
}
set_reflog_expiry_param(&cb.cmd, explicit_expiry, ref);
status |= reflog_expire(ref, sha1, flags,
reflog_expiry_prepare,
should_expire_reflog_ent,
reflog_expiry_cleanup,
&cb);
}
return status;
}
static int count_reflog_ent(struct object_id *ooid, struct object_id *noid,
const char *email, timestamp_t timestamp, int tz,
const char *message, void *cb_data)
{
struct expire_reflog_policy_cb *cb = cb_data;
if (!cb->cmd.expire_total || timestamp < cb->cmd.expire_total)
cb->cmd.recno++;
return 0;
}
static int cmd_reflog_delete(int argc, const char **argv, const char *prefix)
{
struct expire_reflog_policy_cb cb;
int i, status = 0;
unsigned int flags = 0;
memset(&cb, 0, sizeof(cb));
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
if (!strcmp(arg, "--dry-run") || !strcmp(arg, "-n"))
flags |= EXPIRE_REFLOGS_DRY_RUN;
else if (!strcmp(arg, "--rewrite"))
flags |= EXPIRE_REFLOGS_REWRITE;
else if (!strcmp(arg, "--updateref"))
flags |= EXPIRE_REFLOGS_UPDATE_REF;
else if (!strcmp(arg, "--verbose"))
flags |= EXPIRE_REFLOGS_VERBOSE;
else if (!strcmp(arg, "--")) {
i++;
break;
}
else if (arg[0] == '-')
usage(reflog_delete_usage);
else
break;
}
if (argc - i < 1)
return error("Nothing to delete?");
for ( ; i < argc; i++) {
const char *spec = strstr(argv[i], "@{");
unsigned char sha1[20];
char *ep, *ref;
int recno;
if (!spec) {
status |= error("Not a reflog: %s", argv[i]);
continue;
}
if (!dwim_log(argv[i], spec - argv[i], sha1, &ref)) {
status |= error("no reflog for '%s'", argv[i]);
continue;
}
recno = strtoul(spec + 2, &ep, 10);
if (*ep == '}') {
cb.cmd.recno = -recno;
for_each_reflog_ent(ref, count_reflog_ent, &cb);
} else {
cb.cmd.expire_total = approxidate(spec + 2);
for_each_reflog_ent(ref, count_reflog_ent, &cb);
cb.cmd.expire_total = 0;
}
status |= reflog_expire(ref, sha1, flags,
reflog_expiry_prepare,
should_expire_reflog_ent,
reflog_expiry_cleanup,
&cb);
free(ref);
}
return status;
}
static int cmd_reflog_exists(int argc, const char **argv, const char *prefix)
{
int i, start = 0;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
if (!strcmp(arg, "--")) {
i++;
break;
}
else if (arg[0] == '-')
usage(reflog_exists_usage);
else
break;
}
start = i;
if (argc - start != 1)
usage(reflog_exists_usage);
if (check_refname_format(argv[start], REFNAME_ALLOW_ONELEVEL))
die("invalid ref format: %s", argv[start]);
return !reflog_exists(argv[start]);
}
/*
* main "reflog"
*/
static const char reflog_usage[] =
"git reflog [ show | expire | delete | exists ]";
int cmd_reflog(int argc, const char **argv, const char *prefix)
{
if (argc > 1 && !strcmp(argv[1], "-h"))
usage(reflog_usage);
/* With no command, we default to showing it. */
if (argc < 2 || *argv[1] == '-')
return cmd_log_reflog(argc, argv, prefix);
if (!strcmp(argv[1], "show"))
return cmd_log_reflog(argc - 1, argv + 1, prefix);
if (!strcmp(argv[1], "expire"))
return cmd_reflog_expire(argc - 1, argv + 1, prefix);
if (!strcmp(argv[1], "delete"))
return cmd_reflog_delete(argc - 1, argv + 1, prefix);
if (!strcmp(argv[1], "exists"))
return cmd_reflog_exists(argc - 1, argv + 1, prefix);
return cmd_log_reflog(argc, argv, prefix);
}