#define USE_THE_REPOSITORY_VARIABLE

#include "git-compat-util.h"

#include "gettext.h"

#include "object-store-ll.h"

#include "reflog.h"

#include "refs.h"

#include "revision.h"

#include "tree.h"

#include "tree-walk.h"

/* Remember to update object flag allocation in object.h */

#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(the_repository, 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 = repo_read_object_file(the_repository, oid, &type,

               &size);

    if (!data) {

      tree->object.flags |= INCOMPLETE;

      return 0;

    }

    tree->buffer = data;

    tree->size = size;

  }

  init_tree_desc(&desc, &tree->object.oid, tree->buffer, tree->size);

  complete = 1;

  while (tree_entry(&desc, &entry)) {

    if (!repo_has_object_file(the_repository, &entry.oid) ||

        (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(the_repository, &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(get_commit_tree_oid(c))) {

        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(the_repository, 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 (repo_parse_commit(the_repository, commit))

      continue;

    commit->object.flags |= REACHABLE;

    if (commit->date < expire_limit) {

      commit_list_insert(commit, &leftover);

      continue;

    }

    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(the_repository, 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.

 */

int should_expire_reflog_ent(struct object_id *ooid, struct object_id *noid,

           const char *email UNUSED,

           timestamp_t timestamp, int tz UNUSED,

           const char *message UNUSED, void *cb_data)

{

  struct expire_reflog_policy_cb *cb = cb_data;

  struct commit *old_commit, *new_commit;

  if (timestamp < cb->cmd.expire_total)

    return 1;

  old_commit = new_commit = NULL;

  if (cb->cmd.stalefix &&

      (!keep_entry(&old_commit, ooid) || !keep_entry(&new_commit, noid)))

    return 1;

  if (timestamp < cb->cmd.expire_unreachable) {

    switch (cb->unreachable_expire_kind) {

    case UE_ALWAYS:

      return 1;

    case UE_NORMAL:

    case UE_HEAD:

      if (unreachable(cb, old_commit, ooid) || unreachable(cb, new_commit, noid))

        return 1;

      break;

    }

  }

  if (cb->cmd.recno && --(cb->cmd.recno) == 0)

    return 1;

  return 0;

}

int should_expire_reflog_ent_verbose(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;

  int expire;

  expire = should_expire_reflog_ent(ooid, noid, email, timestamp, tz,

            message, cb);

  if (!expire)

    printf("keep %s", message);

  else if (cb->dry_run)

    printf("would prune %s", message);

  else

    printf("prune %s", message);

  return expire;

}

static int push_tip_to_list(const char *refname UNUSED,

          const char *referent UNUSED,

          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(the_repository, oid, 1);

  if (!tip_commit)

    return 0;

  commit_list_insert(tip_commit, list);

  return 0;

}

static int is_head(const char *refname)

{

  const char *stripped_refname;

  parse_worktree_ref(refname, NULL, NULL, &stripped_refname);

  return !strcmp(stripped_refname, "HEAD");

}

void reflog_expiry_prepare(const char *refname,

         const struct object_id *oid,

         void *cb_data)

{

  struct expire_reflog_policy_cb *cb = cb_data;

  struct commit_list *elem;

  struct commit *commit = NULL;

  if (!cb->cmd.expire_unreachable || is_head(refname)) {

    cb->unreachable_expire_kind = UE_HEAD;

  } else {

    commit = lookup_commit_reference_gently(the_repository,

              oid, 1);

    if (commit && is_null_oid(&commit->object.oid))

      commit = NULL;

    cb->unreachable_expire_kind = commit ? UE_NORMAL : UE_ALWAYS;

  }

  if (cb->cmd.expire_unreachable <= cb->cmd.expire_total)

    cb->unreachable_expire_kind = UE_ALWAYS;

  switch (cb->unreachable_expire_kind) {

  case UE_ALWAYS:

    return;

  case UE_HEAD:

    refs_for_each_ref(get_main_ref_store(the_repository),

          push_tip_to_list, &cb->tips);

    for (elem = cb->tips; elem; elem = elem->next)

      commit_list_insert(elem->item, &cb->mark_list);

    break;

  case UE_NORMAL:

    commit_list_insert(commit, &cb->mark_list);

    /* For reflog_expiry_cleanup() below */

    cb->tip_commit = commit;

  }

  cb->mark_limit = cb->cmd.expire_total;

  mark_reachable(cb);

}

void reflog_expiry_cleanup(void *cb_data)

{

  struct expire_reflog_policy_cb *cb = cb_data;

  struct commit_list *elem;

  switch (cb->unreachable_expire_kind) {

  case UE_ALWAYS:

    return;

  case UE_HEAD:

    for (elem = cb->tips; elem; elem = elem->next)

      clear_commit_marks(elem->item, REACHABLE);

    free_commit_list(cb->tips);

    break;

  case UE_NORMAL:

    clear_commit_marks(cb->tip_commit, REACHABLE);

    break;

  }

  for (elem = cb->mark_list; elem; elem = elem->next)

    clear_commit_marks(elem->item, REACHABLE);

  free_commit_list(cb->mark_list);

}

int count_reflog_ent(struct object_id *ooid UNUSED,

         struct object_id *noid UNUSED,

         const char *email UNUSED,

         timestamp_t timestamp, int tz UNUSED,

         const char *message UNUSED, void *cb_data)

{

  struct cmd_reflog_expire_cb *cb = cb_data;

  if (!cb->expire_total || timestamp < cb->expire_total)

    cb->recno++;

  return 0;

}

int reflog_delete(const char *rev, enum expire_reflog_flags flags, int verbose)

{

  struct cmd_reflog_expire_cb cmd = { 0 };

  int status = 0;

  reflog_expiry_should_prune_fn *should_prune_fn = should_expire_reflog_ent;

  const char *spec = strstr(rev, "@{");

  char *ep, *ref;

  int recno;

  struct expire_reflog_policy_cb cb = {

    .dry_run = !!(flags & EXPIRE_REFLOGS_DRY_RUN),

  };

  if (verbose)

    should_prune_fn = should_expire_reflog_ent_verbose;

  if (!spec)

    return error(_("not a reflog: %s"), rev);

  if (!repo_dwim_log(the_repository, rev, spec - rev, NULL, &ref)) {

    status |= error(_("no reflog for '%s'"), rev);

    goto cleanup;

  }

  recno = strtoul(spec + 2, &ep, 10);

  if (*ep == '}') {

    cmd.recno = -recno;

    refs_for_each_reflog_ent(get_main_ref_store(the_repository),

           ref, count_reflog_ent, &cmd);

  } else {

    cmd.expire_total = approxidate(spec + 2);

    refs_for_each_reflog_ent(get_main_ref_store(the_repository),

           ref, count_reflog_ent, &cmd);

    cmd.expire_total = 0;

  }

  cb.cmd = cmd;

  status |= refs_reflog_expire(get_main_ref_store(the_repository), ref,

             flags,

             reflog_expiry_prepare,

             should_prune_fn,

             reflog_expiry_cleanup,

             &cb);

 cleanup:

  free(ref);

  return status;

}