]> git.proxmox.com Git - libgit2.git/blobdiff - src/libgit2/revwalk.c
Merge https://salsa.debian.org/debian/libgit2 into proxmox/bullseye
[libgit2.git] / src / libgit2 / revwalk.c
diff --git a/src/libgit2/revwalk.c b/src/libgit2/revwalk.c
new file mode 100644 (file)
index 0000000..553e049
--- /dev/null
@@ -0,0 +1,820 @@
+/*
+ * Copyright (C) the libgit2 contributors. All rights reserved.
+ *
+ * This file is part of libgit2, distributed under the GNU GPL v2 with
+ * a Linking Exception. For full terms see the included COPYING file.
+ */
+
+#include "revwalk.h"
+
+#include "commit.h"
+#include "odb.h"
+#include "pool.h"
+
+#include "git2/revparse.h"
+#include "merge.h"
+#include "vector.h"
+
+static int get_revision(git_commit_list_node **out, git_revwalk *walk, git_commit_list **list);
+
+git_commit_list_node *git_revwalk__commit_lookup(
+       git_revwalk *walk, const git_oid *oid)
+{
+       git_commit_list_node *commit;
+
+       /* lookup and reserve space if not already present */
+       if ((commit = git_oidmap_get(walk->commits, oid)) != NULL)
+               return commit;
+
+       commit = git_commit_list_alloc_node(walk);
+       if (commit == NULL)
+               return NULL;
+
+       git_oid_cpy(&commit->oid, oid);
+
+       if ((git_oidmap_set(walk->commits, &commit->oid, commit)) < 0)
+               return NULL;
+
+       return commit;
+}
+
+int git_revwalk__push_commit(git_revwalk *walk, const git_oid *oid, const git_revwalk__push_options *opts)
+{
+       git_oid commit_id;
+       int error;
+       git_object *obj, *oobj;
+       git_commit_list_node *commit;
+       git_commit_list *list;
+
+       if ((error = git_object_lookup(&oobj, walk->repo, oid, GIT_OBJECT_ANY)) < 0)
+               return error;
+
+       error = git_object_peel(&obj, oobj, GIT_OBJECT_COMMIT);
+       git_object_free(oobj);
+
+       if (error == GIT_ENOTFOUND || error == GIT_EINVALIDSPEC || error == GIT_EPEEL) {
+               /* If this comes from e.g. push_glob("tags"), ignore this */
+               if (opts->from_glob)
+                       return 0;
+
+               git_error_set(GIT_ERROR_INVALID, "object is not a committish");
+               return error;
+       }
+       if (error < 0)
+               return error;
+
+       git_oid_cpy(&commit_id, git_object_id(obj));
+       git_object_free(obj);
+
+       commit = git_revwalk__commit_lookup(walk, &commit_id);
+       if (commit == NULL)
+               return -1; /* error already reported by failed lookup */
+
+       /* A previous hide already told us we don't want this commit  */
+       if (commit->uninteresting)
+               return 0;
+
+       if (opts->uninteresting) {
+               walk->limited = 1;
+               walk->did_hide = 1;
+       } else {
+               walk->did_push = 1;
+       }
+
+       commit->uninteresting = opts->uninteresting;
+       list = walk->user_input;
+       if ((opts->insert_by_date &&
+           git_commit_list_insert_by_date(commit, &list) == NULL) ||
+           git_commit_list_insert(commit, &list) == NULL) {
+               git_error_set_oom();
+               return -1;
+       }
+
+       walk->user_input = list;
+
+       return 0;
+}
+
+int git_revwalk_push(git_revwalk *walk, const git_oid *oid)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+
+       GIT_ASSERT_ARG(walk);
+       GIT_ASSERT_ARG(oid);
+
+       return git_revwalk__push_commit(walk, oid, &opts);
+}
+
+
+int git_revwalk_hide(git_revwalk *walk, const git_oid *oid)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+
+       GIT_ASSERT_ARG(walk);
+       GIT_ASSERT_ARG(oid);
+
+       opts.uninteresting = 1;
+       return git_revwalk__push_commit(walk, oid, &opts);
+}
+
+int git_revwalk__push_ref(git_revwalk *walk, const char *refname, const git_revwalk__push_options *opts)
+{
+       git_oid oid;
+
+       if (git_reference_name_to_id(&oid, walk->repo, refname) < 0)
+               return -1;
+
+       return git_revwalk__push_commit(walk, &oid, opts);
+}
+
+int git_revwalk__push_glob(git_revwalk *walk, const char *glob, const git_revwalk__push_options *given_opts)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+       int error = 0;
+       git_str buf = GIT_STR_INIT;
+       git_reference *ref;
+       git_reference_iterator *iter;
+       size_t wildcard;
+
+       GIT_ASSERT_ARG(walk);
+       GIT_ASSERT_ARG(glob);
+
+       if (given_opts)
+               memcpy(&opts, given_opts, sizeof(opts));
+
+       /* refs/ is implied if not given in the glob */
+       if (git__prefixcmp(glob, GIT_REFS_DIR) != 0)
+               git_str_joinpath(&buf, GIT_REFS_DIR, glob);
+       else
+               git_str_puts(&buf, glob);
+       GIT_ERROR_CHECK_ALLOC_STR(&buf);
+
+       /* If no '?', '*' or '[' exist, we append '/ *' to the glob */
+       wildcard = strcspn(glob, "?*[");
+       if (!glob[wildcard])
+               git_str_put(&buf, "/*", 2);
+
+       if ((error = git_reference_iterator_glob_new(&iter, walk->repo, buf.ptr)) < 0)
+               goto out;
+
+       opts.from_glob = true;
+       while ((error = git_reference_next(&ref, iter)) == 0) {
+               error = git_revwalk__push_ref(walk, git_reference_name(ref), &opts);
+               git_reference_free(ref);
+               if (error < 0)
+                       break;
+       }
+       git_reference_iterator_free(iter);
+
+       if (error == GIT_ITEROVER)
+               error = 0;
+out:
+       git_str_dispose(&buf);
+       return error;
+}
+
+int git_revwalk_push_glob(git_revwalk *walk, const char *glob)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+
+       GIT_ASSERT_ARG(walk);
+       GIT_ASSERT_ARG(glob);
+
+       return git_revwalk__push_glob(walk, glob, &opts);
+}
+
+int git_revwalk_hide_glob(git_revwalk *walk, const char *glob)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+
+       GIT_ASSERT_ARG(walk);
+       GIT_ASSERT_ARG(glob);
+
+       opts.uninteresting = 1;
+       return git_revwalk__push_glob(walk, glob, &opts);
+}
+
+int git_revwalk_push_head(git_revwalk *walk)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+
+       GIT_ASSERT_ARG(walk);
+
+       return git_revwalk__push_ref(walk, GIT_HEAD_FILE, &opts);
+}
+
+int git_revwalk_hide_head(git_revwalk *walk)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+
+       GIT_ASSERT_ARG(walk);
+
+       opts.uninteresting = 1;
+       return git_revwalk__push_ref(walk, GIT_HEAD_FILE, &opts);
+}
+
+int git_revwalk_push_ref(git_revwalk *walk, const char *refname)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+
+       GIT_ASSERT_ARG(walk);
+       GIT_ASSERT_ARG(refname);
+
+       return git_revwalk__push_ref(walk, refname, &opts);
+}
+
+int git_revwalk_push_range(git_revwalk *walk, const char *range)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+       git_revspec revspec;
+       int error = 0;
+
+       if ((error = git_revparse(&revspec, walk->repo, range)))
+               return error;
+
+       if (!revspec.to) {
+               git_error_set(GIT_ERROR_INVALID, "invalid revspec: range not provided");
+               error = GIT_EINVALIDSPEC;
+               goto out;
+       }
+
+       if (revspec.flags & GIT_REVSPEC_MERGE_BASE) {
+               /* TODO: support "<commit>...<commit>" */
+               git_error_set(GIT_ERROR_INVALID, "symmetric differences not implemented in revwalk");
+               error = GIT_EINVALIDSPEC;
+               goto out;
+       }
+
+       opts.uninteresting = 1;
+       if ((error = git_revwalk__push_commit(walk, git_object_id(revspec.from), &opts)))
+               goto out;
+
+       opts.uninteresting = 0;
+       error = git_revwalk__push_commit(walk, git_object_id(revspec.to), &opts);
+
+out:
+       git_object_free(revspec.from);
+       git_object_free(revspec.to);
+       return error;
+}
+
+int git_revwalk_hide_ref(git_revwalk *walk, const char *refname)
+{
+       git_revwalk__push_options opts = GIT_REVWALK__PUSH_OPTIONS_INIT;
+
+       GIT_ASSERT_ARG(walk);
+       GIT_ASSERT_ARG(refname);
+
+       opts.uninteresting = 1;
+       return git_revwalk__push_ref(walk, refname, &opts);
+}
+
+static int revwalk_enqueue_timesort(git_revwalk *walk, git_commit_list_node *commit)
+{
+       return git_pqueue_insert(&walk->iterator_time, commit);
+}
+
+static int revwalk_enqueue_unsorted(git_revwalk *walk, git_commit_list_node *commit)
+{
+       return git_commit_list_insert(commit, &walk->iterator_rand) ? 0 : -1;
+}
+
+static int revwalk_next_timesort(git_commit_list_node **object_out, git_revwalk *walk)
+{
+       git_commit_list_node *next;
+
+       while ((next = git_pqueue_pop(&walk->iterator_time)) != NULL) {
+               /* Some commits might become uninteresting after being added to the list */
+               if (!next->uninteresting) {
+                       *object_out = next;
+                       return 0;
+               }
+       }
+
+       git_error_clear();
+       return GIT_ITEROVER;
+}
+
+static int revwalk_next_unsorted(git_commit_list_node **object_out, git_revwalk *walk)
+{
+       int error;
+       git_commit_list_node *next;
+
+       while (!(error = get_revision(&next, walk, &walk->iterator_rand))) {
+               /* Some commits might become uninteresting after being added to the list */
+               if (!next->uninteresting) {
+                       *object_out = next;
+                       return 0;
+               }
+       }
+
+       return error;
+}
+
+static int revwalk_next_toposort(git_commit_list_node **object_out, git_revwalk *walk)
+{
+       int error;
+       git_commit_list_node *next;
+
+       while (!(error = get_revision(&next, walk, &walk->iterator_topo))) {
+               /* Some commits might become uninteresting after being added to the list */
+               if (!next->uninteresting) {
+                       *object_out = next;
+                       return 0;
+               }
+       }
+
+       return error;
+}
+
+static int revwalk_next_reverse(git_commit_list_node **object_out, git_revwalk *walk)
+{
+       *object_out = git_commit_list_pop(&walk->iterator_reverse);
+       return *object_out ? 0 : GIT_ITEROVER;
+}
+
+static void mark_parents_uninteresting(git_commit_list_node *commit)
+{
+       unsigned short i;
+       git_commit_list *parents = NULL;
+
+       for (i = 0; i < commit->out_degree; i++)
+               git_commit_list_insert(commit->parents[i], &parents);
+
+
+       while (parents) {
+               commit = git_commit_list_pop(&parents);
+
+               while (commit) {
+                       if (commit->uninteresting)
+                               break;
+
+                       commit->uninteresting = 1;
+                       /*
+                        * If we've reached this commit some other way
+                        * already, we need to mark its parents uninteresting
+                        * as well.
+                        */
+                       if (!commit->parents)
+                               break;
+
+                       for (i = 0; i < commit->out_degree; i++)
+                               git_commit_list_insert(commit->parents[i], &parents);
+                       commit = commit->parents[0];
+               }
+       }
+}
+
+static int add_parents_to_list(git_revwalk *walk, git_commit_list_node *commit, git_commit_list **list)
+{
+       unsigned short i;
+       int error;
+
+       if (commit->added)
+               return 0;
+
+       commit->added = 1;
+
+       /*
+        * Go full on in the uninteresting case as we want to include
+        * as many of these as we can.
+        *
+        * Usually we haven't parsed the parent of a parent, but if we
+        * have it we reached it via other means so we want to mark
+        * its parents recursively too.
+        */
+       if (commit->uninteresting) {
+               for (i = 0; i < commit->out_degree; i++) {
+                       git_commit_list_node *p = commit->parents[i];
+                       p->uninteresting = 1;
+
+                       /* git does it gently here, but we don't like missing objects */
+                       if ((error = git_commit_list_parse(walk, p)) < 0)
+                               return error;
+
+                       if (p->parents)
+                               mark_parents_uninteresting(p);
+
+                       p->seen = 1;
+                       git_commit_list_insert_by_date(p, list);
+               }
+
+               return 0;
+       }
+
+       /*
+        * Now on to what we do if the commit is indeed
+        * interesting. Here we do want things like first-parent take
+        * effect as this is what we'll be showing.
+        */
+       for (i = 0; i < commit->out_degree; i++) {
+               git_commit_list_node *p = commit->parents[i];
+
+               if ((error = git_commit_list_parse(walk, p)) < 0)
+                       return error;
+
+               if (walk->hide_cb && walk->hide_cb(&p->oid, walk->hide_cb_payload))
+                       continue;
+
+               if (!p->seen) {
+                       p->seen = 1;
+                       git_commit_list_insert_by_date(p, list);
+               }
+
+               if (walk->first_parent)
+                       break;
+       }
+       return 0;
+}
+
+/* How many uninteresting commits we want to look at after we run out of interesting ones */
+#define SLOP 5
+
+static int still_interesting(git_commit_list *list, int64_t time, int slop)
+{
+       /* The empty list is pretty boring */
+       if (!list)
+               return 0;
+
+       /*
+        * If the destination list has commits with an earlier date than our
+        * source, we want to reset the slop counter as we're not done.
+        */
+       if (time <= list->item->time)
+               return SLOP;
+
+       for (; list; list = list->next) {
+               /*
+                * If the destination list still contains interesting commits we
+                * want to continue looking.
+                */
+               if (!list->item->uninteresting || list->item->time > time)
+                       return SLOP;
+       }
+
+       /* Everything's uninteresting, reduce the count */
+       return slop - 1;
+}
+
+static int limit_list(git_commit_list **out, git_revwalk *walk, git_commit_list *commits)
+{
+       int error, slop = SLOP;
+       int64_t time = INT64_MAX;
+       git_commit_list *list = commits;
+       git_commit_list *newlist = NULL;
+       git_commit_list **p = &newlist;
+
+       while (list) {
+               git_commit_list_node *commit = git_commit_list_pop(&list);
+
+               if ((error = add_parents_to_list(walk, commit, &list)) < 0)
+                       return error;
+
+               if (commit->uninteresting) {
+                       mark_parents_uninteresting(commit);
+
+                       slop = still_interesting(list, time, slop);
+                       if (slop)
+                               continue;
+
+                       break;
+               }
+
+               if (walk->hide_cb && walk->hide_cb(&commit->oid, walk->hide_cb_payload))
+                       continue;
+
+               time = commit->time;
+               p = &git_commit_list_insert(commit, p)->next;
+       }
+
+       git_commit_list_free(&list);
+       *out = newlist;
+       return 0;
+}
+
+static int get_revision(git_commit_list_node **out, git_revwalk *walk, git_commit_list **list)
+{
+       int error;
+       git_commit_list_node *commit;
+
+       commit = git_commit_list_pop(list);
+       if (!commit) {
+               git_error_clear();
+               return GIT_ITEROVER;
+       }
+
+       /*
+        * If we did not run limit_list and we must add parents to the
+        * list ourselves.
+        */
+       if (!walk->limited) {
+               if ((error = add_parents_to_list(walk, commit, list)) < 0)
+                       return error;
+       }
+
+       *out = commit;
+       return 0;
+}
+
+static int sort_in_topological_order(git_commit_list **out, git_revwalk *walk, git_commit_list *list)
+{
+       git_commit_list *ll = NULL, *newlist, **pptr;
+       git_commit_list_node *next;
+       git_pqueue queue;
+       git_vector_cmp queue_cmp = NULL;
+       unsigned short i;
+       int error;
+
+       if (walk->sorting & GIT_SORT_TIME)
+               queue_cmp = git_commit_list_time_cmp;
+
+       if ((error = git_pqueue_init(&queue, 0, 8, queue_cmp)))
+               return error;
+
+       /*
+        * Start by resetting the in-degree to 1 for the commits in
+        * our list. We want to go through this list again, so we
+        * store it in the commit list as we extract it from the lower
+        * machinery.
+        */
+       for (ll = list; ll; ll = ll->next) {
+               ll->item->in_degree = 1;
+       }
+
+       /*
+        * Count up how many children each commit has. We limit
+        * ourselves to those commits in the original list (in-degree
+        * of 1) avoiding setting it for any parent that was hidden.
+        */
+       for(ll = list; ll; ll = ll->next) {
+               for (i = 0; i < ll->item->out_degree; ++i) {
+                       git_commit_list_node *parent = ll->item->parents[i];
+                       if (parent->in_degree)
+                               parent->in_degree++;
+               }
+       }
+
+       /*
+        * Now we find the tips i.e. those not reachable from any other node
+        * i.e. those which still have an in-degree of 1.
+        */
+       for(ll = list; ll; ll = ll->next) {
+               if (ll->item->in_degree == 1) {
+                       if ((error = git_pqueue_insert(&queue, ll->item)))
+                               goto cleanup;
+               }
+       }
+
+       /*
+        * We need to output the tips in the order that they came out of the
+        * traversal, so if we're not doing time-sorting, we need to reverse the
+        * pqueue in order to get them to come out as we inserted them.
+        */
+       if ((walk->sorting & GIT_SORT_TIME) == 0)
+               git_pqueue_reverse(&queue);
+
+
+       pptr = &newlist;
+       newlist = NULL;
+       while ((next = git_pqueue_pop(&queue)) != NULL) {
+               for (i = 0; i < next->out_degree; ++i) {
+                       git_commit_list_node *parent = next->parents[i];
+                       if (parent->in_degree == 0)
+                               continue;
+
+                       if (--parent->in_degree == 1) {
+                               if ((error = git_pqueue_insert(&queue, parent)))
+                                       goto cleanup;
+                       }
+               }
+
+               /* All the children of 'item' have been emitted (since we got to it via the priority queue) */
+               next->in_degree = 0;
+
+               pptr = &git_commit_list_insert(next, pptr)->next;
+       }
+
+       *out = newlist;
+       error = 0;
+
+cleanup:
+       git_pqueue_free(&queue);
+       return error;
+}
+
+static int prepare_walk(git_revwalk *walk)
+{
+       int error = 0;
+       git_commit_list *list, *commits = NULL;
+       git_commit_list_node *next;
+
+       /* If there were no pushes, we know that the walk is already over */
+       if (!walk->did_push) {
+               git_error_clear();
+               return GIT_ITEROVER;
+       }
+
+       for (list = walk->user_input; list; list = list->next) {
+               git_commit_list_node *commit = list->item;
+               if ((error = git_commit_list_parse(walk, commit)) < 0)
+                       return error;
+
+               if (commit->uninteresting)
+                       mark_parents_uninteresting(commit);
+
+               if (!commit->seen) {
+                       commit->seen = 1;
+                       git_commit_list_insert(commit, &commits);
+               }
+       }
+
+       if (walk->limited && (error = limit_list(&commits, walk, commits)) < 0)
+               return error;
+
+       if (walk->sorting & GIT_SORT_TOPOLOGICAL) {
+               error = sort_in_topological_order(&walk->iterator_topo, walk, commits);
+               git_commit_list_free(&commits);
+
+               if (error < 0)
+                       return error;
+
+               walk->get_next = &revwalk_next_toposort;
+       } else if (walk->sorting & GIT_SORT_TIME) {
+               for (list = commits; list && !error; list = list->next)
+                       error = walk->enqueue(walk, list->item);
+
+               git_commit_list_free(&commits);
+
+               if (error < 0)
+                       return error;
+       } else {
+               walk->iterator_rand = commits;
+               walk->get_next = revwalk_next_unsorted;
+       }
+
+       if (walk->sorting & GIT_SORT_REVERSE) {
+
+               while ((error = walk->get_next(&next, walk)) == 0)
+                       if (git_commit_list_insert(next, &walk->iterator_reverse) == NULL)
+                               return -1;
+
+               if (error != GIT_ITEROVER)
+                       return error;
+
+               walk->get_next = &revwalk_next_reverse;
+       }
+
+       walk->walking = 1;
+       return 0;
+}
+
+
+int git_revwalk_new(git_revwalk **revwalk_out, git_repository *repo)
+{
+       git_revwalk *walk = git__calloc(1, sizeof(git_revwalk));
+       GIT_ERROR_CHECK_ALLOC(walk);
+
+       if (git_oidmap_new(&walk->commits) < 0 ||
+           git_pqueue_init(&walk->iterator_time, 0, 8, git_commit_list_time_cmp) < 0 ||
+           git_pool_init(&walk->commit_pool, COMMIT_ALLOC) < 0)
+               return -1;
+
+       walk->get_next = &revwalk_next_unsorted;
+       walk->enqueue = &revwalk_enqueue_unsorted;
+
+       walk->repo = repo;
+
+       if (git_repository_odb(&walk->odb, repo) < 0) {
+               git_revwalk_free(walk);
+               return -1;
+       }
+
+       *revwalk_out = walk;
+       return 0;
+}
+
+void git_revwalk_free(git_revwalk *walk)
+{
+       if (walk == NULL)
+               return;
+
+       git_revwalk_reset(walk);
+       git_odb_free(walk->odb);
+
+       git_oidmap_free(walk->commits);
+       git_pool_clear(&walk->commit_pool);
+       git_pqueue_free(&walk->iterator_time);
+       git__free(walk);
+}
+
+git_repository *git_revwalk_repository(git_revwalk *walk)
+{
+       GIT_ASSERT_ARG_WITH_RETVAL(walk, NULL);
+
+       return walk->repo;
+}
+
+int git_revwalk_sorting(git_revwalk *walk, unsigned int sort_mode)
+{
+       GIT_ASSERT_ARG(walk);
+
+       if (walk->walking)
+               git_revwalk_reset(walk);
+
+       walk->sorting = sort_mode;
+
+       if (walk->sorting & GIT_SORT_TIME) {
+               walk->get_next = &revwalk_next_timesort;
+               walk->enqueue = &revwalk_enqueue_timesort;
+       } else {
+               walk->get_next = &revwalk_next_unsorted;
+               walk->enqueue = &revwalk_enqueue_unsorted;
+       }
+
+       if (walk->sorting != GIT_SORT_NONE)
+               walk->limited = 1;
+
+       return 0;
+}
+
+int git_revwalk_simplify_first_parent(git_revwalk *walk)
+{
+       walk->first_parent = 1;
+       return 0;
+}
+
+int git_revwalk_next(git_oid *oid, git_revwalk *walk)
+{
+       int error;
+       git_commit_list_node *next;
+
+       GIT_ASSERT_ARG(walk);
+       GIT_ASSERT_ARG(oid);
+
+       if (!walk->walking) {
+               if ((error = prepare_walk(walk)) < 0)
+                       return error;
+       }
+
+       error = walk->get_next(&next, walk);
+
+       if (error == GIT_ITEROVER) {
+               git_revwalk_reset(walk);
+               git_error_clear();
+               return GIT_ITEROVER;
+       }
+
+       if (!error)
+               git_oid_cpy(oid, &next->oid);
+
+       return error;
+}
+
+int git_revwalk_reset(git_revwalk *walk)
+{
+       git_commit_list_node *commit;
+
+       GIT_ASSERT_ARG(walk);
+
+       git_oidmap_foreach_value(walk->commits, commit, {
+               commit->seen = 0;
+               commit->in_degree = 0;
+               commit->topo_delay = 0;
+               commit->uninteresting = 0;
+               commit->added = 0;
+               commit->flags = 0;
+               });
+
+       git_pqueue_clear(&walk->iterator_time);
+       git_commit_list_free(&walk->iterator_topo);
+       git_commit_list_free(&walk->iterator_rand);
+       git_commit_list_free(&walk->iterator_reverse);
+       git_commit_list_free(&walk->user_input);
+       walk->first_parent = 0;
+       walk->walking = 0;
+       walk->limited = 0;
+       walk->did_push = walk->did_hide = 0;
+       walk->sorting = GIT_SORT_NONE;
+
+       return 0;
+}
+
+int git_revwalk_add_hide_cb(
+       git_revwalk *walk,
+       git_revwalk_hide_cb hide_cb,
+       void *payload)
+{
+       GIT_ASSERT_ARG(walk);
+
+       if (walk->walking)
+               git_revwalk_reset(walk);
+
+       walk->hide_cb = hide_cb;
+       walk->hide_cb_payload = payload;
+
+       if (hide_cb)
+               walk->limited = 1;
+
+       return 0;
+}
+