static int maybe_modified()

in src/diff_generate.c [735:881]
99 lines of code
49 McCabe index (conditional complexity)

static int maybe_modified(
	git_diff_generated *diff,
	diff_in_progress *info)
{
	git_oid noid;
	git_delta_t status = GIT_DELTA_MODIFIED;
	const git_index_entry *oitem = info->oitem;
	const git_index_entry *nitem = info->nitem;
	unsigned int omode = oitem->mode;
	unsigned int nmode = nitem->mode;
	bool new_is_workdir = (info->new_iter->type == GIT_ITERATOR_WORKDIR);
	bool modified_uncertain = false;
	const char *matched_pathspec;
	int error = 0;

	if (!diff_pathspec_match(&matched_pathspec, diff, oitem))
		return 0;

	memset(&noid, 0, sizeof(noid));

	/* on platforms with no symlinks, preserve mode of existing symlinks */
	if (S_ISLNK(omode) && S_ISREG(nmode) && new_is_workdir &&
		!(diff->diffcaps & GIT_DIFFCAPS_HAS_SYMLINKS))
		nmode = omode;

	/* on platforms with no execmode, just preserve old mode */
	if (!(diff->diffcaps & GIT_DIFFCAPS_TRUST_MODE_BITS) &&
		(nmode & MODE_BITS_MASK) != (omode & MODE_BITS_MASK) &&
		new_is_workdir)
		nmode = (nmode & ~MODE_BITS_MASK) | (omode & MODE_BITS_MASK);

	/* if one side is a conflict, mark the whole delta as conflicted */
	if (git_index_entry_is_conflict(oitem) ||
			git_index_entry_is_conflict(nitem)) {
		status = GIT_DELTA_CONFLICTED;

	/* support "assume unchanged" (poorly, b/c we still stat everything) */
	} else if ((oitem->flags & GIT_INDEX_ENTRY_VALID) != 0) {
		status = GIT_DELTA_UNMODIFIED;

	/* support "skip worktree" index bit */
	} else if ((oitem->flags_extended & GIT_INDEX_ENTRY_SKIP_WORKTREE) != 0) {
		status = GIT_DELTA_UNMODIFIED;

	/* if basic type of file changed, then split into delete and add */
	} else if (GIT_MODE_TYPE(omode) != GIT_MODE_TYPE(nmode)) {
		if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_INCLUDE_TYPECHANGE)) {
			status = GIT_DELTA_TYPECHANGE;
		}

		else if (nmode == GIT_FILEMODE_UNREADABLE) {
			if (!(error = diff_delta__from_one(diff, GIT_DELTA_DELETED, oitem, NULL)))
				error = diff_delta__from_one(diff, GIT_DELTA_UNREADABLE, NULL, nitem);
			return error;
		}

		else {
			if (!(error = diff_delta__from_one(diff, GIT_DELTA_DELETED, oitem, NULL)))
				error = diff_delta__from_one(diff, GIT_DELTA_ADDED, NULL, nitem);
			return error;
		}

	/* if oids and modes match (and are valid), then file is unmodified */
	} else if (git_oid_equal(&oitem->id, &nitem->id) &&
			 omode == nmode &&
			 !git_oid_is_zero(&oitem->id)) {
		status = GIT_DELTA_UNMODIFIED;

	/* if we have an unknown OID and a workdir iterator, then check some
	 * circumstances that can accelerate things or need special handling
	 */
	} else if (git_oid_is_zero(&nitem->id) && new_is_workdir) {
		bool use_ctime =
			((diff->diffcaps & GIT_DIFFCAPS_TRUST_CTIME) != 0);
		git_index *index = git_iterator_index(info->new_iter);

		status = GIT_DELTA_UNMODIFIED;

		if (S_ISGITLINK(nmode)) {
			if ((error = maybe_modified_submodule(&status, &noid, diff, info)) < 0)
				return error;
		}

		/* if the stat data looks different, then mark modified - this just
		 * means that the OID will be recalculated below to confirm change
		 */
		else if (omode != nmode || oitem->file_size != nitem->file_size) {
			status = GIT_DELTA_MODIFIED;
			modified_uncertain =
				(oitem->file_size <= 0 && nitem->file_size > 0);
		}
		else if (!git_index_time_eq(&oitem->mtime, &nitem->mtime) ||
			(use_ctime && !git_index_time_eq(&oitem->ctime, &nitem->ctime)) ||
			oitem->ino != nitem->ino ||
			oitem->uid != nitem->uid ||
			oitem->gid != nitem->gid ||
			git_index_entry_newer_than_index(nitem, index))
		{
			status = GIT_DELTA_MODIFIED;
			modified_uncertain = true;
		}

	/* if mode is GITLINK and submodules are ignored, then skip */
	} else if (S_ISGITLINK(nmode) &&
			 DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES)) {
		status = GIT_DELTA_UNMODIFIED;
	}

	/* if we got here and decided that the files are modified, but we
	 * haven't calculated the OID of the new item, then calculate it now
	 */
	if (modified_uncertain && git_oid_is_zero(&nitem->id)) {
		const git_oid *update_check =
			DIFF_FLAG_IS_SET(diff, GIT_DIFF_UPDATE_INDEX) && omode == nmode ?
			&oitem->id : NULL;

		if ((error = git_diff__oid_for_entry(
				&noid, &diff->base, nitem, nmode, update_check)) < 0)
			return error;

		/* if oid matches, then mark unmodified (except submodules, where
		 * the filesystem content may be modified even if the oid still
		 * matches between the index and the workdir HEAD)
		 */
		if (omode == nmode && !S_ISGITLINK(omode) &&
			git_oid_equal(&oitem->id, &noid))
			status = GIT_DELTA_UNMODIFIED;
	}

	/* If we want case changes, then break this into a delete of the old
	 * and an add of the new so that consumers can act accordingly (eg,
	 * checkout will update the case on disk.)
	 */
	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_CASE) &&
		DIFF_FLAG_IS_SET(diff, GIT_DIFF_INCLUDE_CASECHANGE) &&
		strcmp(oitem->path, nitem->path) != 0) {

		if (!(error = diff_delta__from_one(diff, GIT_DELTA_DELETED, oitem, NULL)))
			error = diff_delta__from_one(diff, GIT_DELTA_ADDED, NULL, nitem);

		return error;
	}

	return diff_delta__from_two(
		diff, status, oitem, omode, nitem, nmode,
		git_oid_is_zero(&noid) ? NULL : &noid, matched_pathspec);
}