thodg/libgit2/src/revwalk.c

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• Hash : 9694ef20
  Author :
  Date : 2018-12-17T09:01:53
  

  oidmap: introduce high-level getter for values The current way of looking up an entry from a map is tightly coupled with the map implementation, as one first has to look up the index of the key and then retrieve the associated value by using the index. As a caller, you usually do not care about any indices at all, though, so this is more complicated than really necessary. Furthermore, it invites for errors to happen if the correct error checking sequence is not being followed. Introduce a new high-level function `git_oidmap_get` that takes a map and a key and returns a pointer to the associated value if such a key exists. Otherwise, a `NULL` pointer is returned. Adjust all callers that can trivially be converted.

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• src/revwalk.c

• /*
   * 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;
  }
  
  static int push_commit(git_revwalk *walk, const git_oid *oid, int uninteresting, int from_glob)
  {
  	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 (from_glob)
  			return 0;
  
  		git_error_set(GIT_ERROR_INVALID, "object is not a committish");
  		return -1;
  	}
  	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 (uninteresting) {
  		walk->limited = 1;
  		walk->did_hide = 1;
  	} else {
  		walk->did_push = 1;
  	}
  
  	commit->uninteresting = uninteresting;
  	list = walk->user_input;
  	if (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)
  {
  	assert(walk && oid);
  	return push_commit(walk, oid, 0, false);
  }
  
  
  int git_revwalk_hide(git_revwalk *walk, const git_oid *oid)
  {
  	assert(walk && oid);
  	return push_commit(walk, oid, 1, false);
  }
  
  static int push_ref(git_revwalk *walk, const char *refname, int hide, int from_glob)
  {
  	git_oid oid;
  
  	if (git_reference_name_to_id(&oid, walk->repo, refname) < 0)
  		return -1;
  
  	return push_commit(walk, &oid, hide, from_glob);
  }
  
  static int push_glob(git_revwalk *walk, const char *glob, int hide)
  {
  	int error = 0;
  	git_buf buf = GIT_BUF_INIT;
  	git_reference *ref;
  	git_reference_iterator *iter;
  	size_t wildcard;
  
  	assert(walk && glob);
  
  	/* refs/ is implied if not given in the glob */
  	if (git__prefixcmp(glob, GIT_REFS_DIR) != 0)
  		git_buf_joinpath(&buf, GIT_REFS_DIR, glob);
  	else
  		git_buf_puts(&buf, glob);
  	GIT_ERROR_CHECK_ALLOC_BUF(&buf);
  
  	/* If no '?', '*' or '[' exist, we append '/ *' to the glob */
  	wildcard = strcspn(glob, "?*[");
  	if (!glob[wildcard])
  		git_buf_put(&buf, "/*", 2);
  
  	if ((error = git_reference_iterator_glob_new(&iter, walk->repo, buf.ptr)) < 0)
  		goto out;
  
  	while ((error = git_reference_next(&ref, iter)) == 0) {
  		error = push_ref(walk, git_reference_name(ref), hide, true);
  		git_reference_free(ref);
  		if (error < 0)
  			break;
  	}
  	git_reference_iterator_free(iter);
  
  	if (error == GIT_ITEROVER)
  		error = 0;
  out:
  	git_buf_dispose(&buf);
  	return error;
  }
  
  int git_revwalk_push_glob(git_revwalk *walk, const char *glob)
  {
  	assert(walk && glob);
  	return push_glob(walk, glob, 0);
  }
  
  int git_revwalk_hide_glob(git_revwalk *walk, const char *glob)
  {
  	assert(walk && glob);
  	return push_glob(walk, glob, 1);
  }
  
  int git_revwalk_push_head(git_revwalk *walk)
  {
  	assert(walk);
  	return push_ref(walk, GIT_HEAD_FILE, 0, false);
  }
  
  int git_revwalk_hide_head(git_revwalk *walk)
  {
  	assert(walk);
  	return push_ref(walk, GIT_HEAD_FILE, 1, false);
  }
  
  int git_revwalk_push_ref(git_revwalk *walk, const char *refname)
  {
  	assert(walk && refname);
  	return push_ref(walk, refname, 0, false);
  }
  
  int git_revwalk_push_range(git_revwalk *walk, const char *range)
  {
  	git_revspec revspec;
  	int error = 0;
  
  	if ((error = git_revparse(&revspec, walk->repo, range)))
  		return error;
  
  	if (revspec.flags & GIT_REVPARSE_MERGE_BASE) {
  		/* TODO: support "<commit>...<commit>" */
  		git_error_set(GIT_ERROR_INVALID, "symmetric differences not implemented in revwalk");
  		return GIT_EINVALIDSPEC;
  	}
  
  	if ((error = push_commit(walk, git_object_id(revspec.from), 1, false)))
  		goto out;
  
  	error = push_commit(walk, git_object_id(revspec.to), 0, false);
  
  out:
  	git_object_free(revspec.from);
  	git_object_free(revspec.to);
  	return error;
  }
  
  int git_revwalk_hide_ref(git_revwalk *walk, const char *refname)
  {
  	assert(walk && refname);
  	return push_ref(walk, refname, 1, false);
  }
  
  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 unintersting 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)
  		return -1;
  
  	if (git_pqueue_init(&walk->iterator_time, 0, 8, git_commit_list_time_cmp) < 0)
  		return -1;
  
  	git_pool_init(&walk->commit_pool, COMMIT_ALLOC);
  	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)
  {
  	assert(walk);
  	return walk->repo;
  }
  
  void git_revwalk_sorting(git_revwalk *walk, unsigned int sort_mode)
  {
  	assert(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;
  }
  
  void git_revwalk_simplify_first_parent(git_revwalk *walk)
  {
  	walk->first_parent = 1;
  }
  
  int git_revwalk_next(git_oid *oid, git_revwalk *walk)
  {
  	int error;
  	git_commit_list_node *next;
  
  	assert(walk && 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;
  }
  
  void git_revwalk_reset(git_revwalk *walk)
  {
  	git_commit_list_node *commit;
  
  	assert(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;
  }
  
  int git_revwalk_add_hide_cb(
  	git_revwalk *walk,
  	git_revwalk_hide_cb hide_cb,
  	void *payload)
  {
  	assert(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;
  }
  
  

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