thodg/libgit2/src/diff.c

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• Hash : 5fa7e469
  Author :
  Date : 2013-04-30T04:13:39
  

  Fix some formatting inconsistency

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• src/diff.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 "common.h"
  #include "diff.h"
  #include "fileops.h"
  #include "config.h"
  #include "attr_file.h"
  #include "filter.h"
  #include "pathspec.h"
  
  #define DIFF_FLAG_IS_SET(DIFF,FLAG) (((DIFF)->opts.flags & (FLAG)) != 0)
  #define DIFF_FLAG_ISNT_SET(DIFF,FLAG) (((DIFF)->opts.flags & (FLAG)) == 0)
  #define DIFF_FLAG_SET(DIFF,FLAG,VAL) (DIFF)->opts.flags = \
  	(VAL) ? ((DIFF)->opts.flags | (FLAG)) : ((DIFF)->opts.flags & ~(VAL))
  
  static git_diff_delta *diff_delta__alloc(
  	git_diff_list *diff,
  	git_delta_t status,
  	const char *path)
  {
  	git_diff_delta *delta = git__calloc(1, sizeof(git_diff_delta));
  	if (!delta)
  		return NULL;
  
  	delta->old_file.path = git_pool_strdup(&diff->pool, path);
  	if (delta->old_file.path == NULL) {
  		git__free(delta);
  		return NULL;
  	}
  
  	delta->new_file.path = delta->old_file.path;
  
  	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_REVERSE)) {
  		switch (status) {
  		case GIT_DELTA_ADDED:   status = GIT_DELTA_DELETED; break;
  		case GIT_DELTA_DELETED: status = GIT_DELTA_ADDED; break;
  		default: break; /* leave other status values alone */
  		}
  	}
  	delta->status = status;
  
  	return delta;
  }
  
  static int diff_notify(
  	const git_diff_list *diff,
  	const git_diff_delta *delta,
  	const char *matched_pathspec)
  {
  	if (!diff->opts.notify_cb)
  		return 0;
  
  	return diff->opts.notify_cb(
  		diff, delta, matched_pathspec, diff->opts.notify_payload);
  }
  
  static int diff_delta__from_one(
  	git_diff_list *diff,
  	git_delta_t   status,
  	const git_index_entry *entry)
  {
  	git_diff_delta *delta;
  	const char *matched_pathspec;
  	int notify_res;
  
  	if (status == GIT_DELTA_IGNORED &&
  		DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_INCLUDE_IGNORED))
  		return 0;
  
  	if (status == GIT_DELTA_UNTRACKED &&
  		DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_INCLUDE_UNTRACKED))
  		return 0;
  
  	if (entry->mode == GIT_FILEMODE_COMMIT &&
  		DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES))
  		return 0;
  
  	if (!git_pathspec_match_path(
  			&diff->pathspec, entry->path,
  			DIFF_FLAG_IS_SET(diff, GIT_DIFF_DISABLE_PATHSPEC_MATCH),
  			DIFF_FLAG_IS_SET(diff, GIT_DIFF_DELTAS_ARE_ICASE),
  			&matched_pathspec))
  		return 0;
  
  	delta = diff_delta__alloc(diff, status, entry->path);
  	GITERR_CHECK_ALLOC(delta);
  
  	/* This fn is just for single-sided diffs */
  	assert(status != GIT_DELTA_MODIFIED);
  
  	if (delta->status == GIT_DELTA_DELETED) {
  		delta->old_file.mode = entry->mode;
  		delta->old_file.size = entry->file_size;
  		git_oid_cpy(&delta->old_file.oid, &entry->oid);
  	} else /* ADDED, IGNORED, UNTRACKED */ {
  		delta->new_file.mode = entry->mode;
  		delta->new_file.size = entry->file_size;
  		git_oid_cpy(&delta->new_file.oid, &entry->oid);
  	}
  
  	delta->old_file.flags |= GIT_DIFF_FLAG_VALID_OID;
  
  	if (delta->status == GIT_DELTA_DELETED ||
  		!git_oid_iszero(&delta->new_file.oid))
  		delta->new_file.flags |= GIT_DIFF_FLAG_VALID_OID;
  
  	notify_res = diff_notify(diff, delta, matched_pathspec);
  
  	if (notify_res)
  		git__free(delta);
  	else if (git_vector_insert(&diff->deltas, delta) < 0) {
  		git__free(delta);
  		return -1;
  	}
  
  	return notify_res < 0 ? GIT_EUSER : 0;
  }
  
  static int diff_delta__from_two(
  	git_diff_list *diff,
  	git_delta_t   status,
  	const git_index_entry *old_entry,
  	uint32_t old_mode,
  	const git_index_entry *new_entry,
  	uint32_t new_mode,
  	git_oid *new_oid,
  	const char *matched_pathspec)
  {
  	git_diff_delta *delta;
  	int notify_res;
  
  	if (status == GIT_DELTA_UNMODIFIED &&
  		DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_INCLUDE_UNMODIFIED))
  		return 0;
  
  	if (old_entry->mode == GIT_FILEMODE_COMMIT &&
  		new_entry->mode == GIT_FILEMODE_COMMIT &&
  		DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES))
  		return 0;
  
  	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_REVERSE)) {
  		uint32_t temp_mode = old_mode;
  		const git_index_entry *temp_entry = old_entry;
  		old_entry = new_entry;
  		new_entry = temp_entry;
  		old_mode = new_mode;
  		new_mode = temp_mode;
  	}
  
  	delta = diff_delta__alloc(diff, status, old_entry->path);
  	GITERR_CHECK_ALLOC(delta);
  
  	git_oid_cpy(&delta->old_file.oid, &old_entry->oid);
  	delta->old_file.size = old_entry->file_size;
  	delta->old_file.mode = old_mode;
  	delta->old_file.flags |= GIT_DIFF_FLAG_VALID_OID;
  
  	git_oid_cpy(&delta->new_file.oid, &new_entry->oid);
  	delta->new_file.size = new_entry->file_size;
  	delta->new_file.mode = new_mode;
  
  	if (new_oid) {
  		if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_REVERSE))
  			git_oid_cpy(&delta->old_file.oid, new_oid);
  		else
  			git_oid_cpy(&delta->new_file.oid, new_oid);
  	}
  
  	if (new_oid || !git_oid_iszero(&new_entry->oid))
  		delta->new_file.flags |= GIT_DIFF_FLAG_VALID_OID;
  
  	notify_res = diff_notify(diff, delta, matched_pathspec);
  
  	if (notify_res)
  		git__free(delta);
  	else if (git_vector_insert(&diff->deltas, delta) < 0) {
  		git__free(delta);
  		return -1;
  	}
  
  	return notify_res < 0 ? GIT_EUSER : 0;
  }
  
  static git_diff_delta *diff_delta__last_for_item(
  	git_diff_list *diff,
  	const git_index_entry *item)
  {
  	git_diff_delta *delta = git_vector_last(&diff->deltas);
  	if (!delta)
  		return NULL;
  
  	switch (delta->status) {
  	case GIT_DELTA_UNMODIFIED:
  	case GIT_DELTA_DELETED:
  		if (git_oid__cmp(&delta->old_file.oid, &item->oid) == 0)
  			return delta;
  		break;
  	case GIT_DELTA_ADDED:
  		if (git_oid__cmp(&delta->new_file.oid, &item->oid) == 0)
  			return delta;
  		break;
  	case GIT_DELTA_UNTRACKED:
  		if (diff->strcomp(delta->new_file.path, item->path) == 0 &&
  			git_oid__cmp(&delta->new_file.oid, &item->oid) == 0)
  			return delta;
  		break;
  	case GIT_DELTA_MODIFIED:
  		if (git_oid__cmp(&delta->old_file.oid, &item->oid) == 0 ||
  			git_oid__cmp(&delta->new_file.oid, &item->oid) == 0)
  			return delta;
  		break;
  	default:
  		break;
  	}
  
  	return NULL;
  }
  
  static char *diff_strdup_prefix(git_pool *pool, const char *prefix)
  {
  	size_t len = strlen(prefix);
  
  	/* append '/' at end if needed */
  	if (len > 0 && prefix[len - 1] != '/')
  		return git_pool_strcat(pool, prefix, "/");
  	else
  		return git_pool_strndup(pool, prefix, len + 1);
  }
  
  int git_diff_delta__cmp(const void *a, const void *b)
  {
  	const git_diff_delta *da = a, *db = b;
  	int val = strcmp(da->old_file.path, db->old_file.path);
  	return val ? val : ((int)da->status - (int)db->status);
  }
  
  bool git_diff_delta__should_skip(
  	const git_diff_options *opts, const git_diff_delta *delta)
  {
  	uint32_t flags = opts ? opts->flags : 0;
  
  	if (delta->status == GIT_DELTA_UNMODIFIED &&
  		(flags & GIT_DIFF_INCLUDE_UNMODIFIED) == 0)
  		return true;
  
  	if (delta->status == GIT_DELTA_IGNORED &&
  		(flags & GIT_DIFF_INCLUDE_IGNORED) == 0)
  		return true;
  
  	if (delta->status == GIT_DELTA_UNTRACKED &&
  		(flags & GIT_DIFF_INCLUDE_UNTRACKED) == 0)
  		return true;
  
  	return false;
  }
  
  
  static int config_bool(git_config *cfg, const char *name, int defvalue)
  {
  	int val = defvalue;
  
  	if (git_config_get_bool(&val, cfg, name) < 0)
  		giterr_clear();
  
  	return val;
  }
  
  static int config_int(git_config *cfg, const char *name, int defvalue)
  {
  	int val = defvalue;
  
  	if (git_config_get_int32(&val, cfg, name) < 0)
  		giterr_clear();
  
  	return val;
  }
  
  static const char *diff_mnemonic_prefix(
  	git_iterator_type_t type, bool left_side)
  {
  	const char *pfx = "";
  
  	switch (type) {
  	case GIT_ITERATOR_TYPE_EMPTY:   pfx = "c"; break;
  	case GIT_ITERATOR_TYPE_TREE:    pfx = "c"; break;
  	case GIT_ITERATOR_TYPE_INDEX:   pfx = "i"; break;
  	case GIT_ITERATOR_TYPE_WORKDIR: pfx = "w"; break;
  	case GIT_ITERATOR_TYPE_FS:      pfx = left_side ? "1" : "2"; break;
  	default: break;
  	}
  
  	/* note: without a deeper look at pathspecs, there is no easy way
  	 * to get the (o)bject / (w)ork tree mnemonics working...
  	 */
  
  	return pfx;
  }
  
  static git_diff_list *diff_list_alloc(
  	git_repository *repo,
  	git_iterator *old_iter,
  	git_iterator *new_iter)
  {
  	git_diff_options dflt = GIT_DIFF_OPTIONS_INIT;
  	git_diff_list *diff = git__calloc(1, sizeof(git_diff_list));
  	if (!diff)
  		return NULL;
  
  	assert(repo && old_iter && new_iter);
  
  	GIT_REFCOUNT_INC(diff);
  	diff->repo = repo;
  	diff->old_src = old_iter->type;
  	diff->new_src = new_iter->type;
  	memcpy(&diff->opts, &dflt, sizeof(diff->opts));
  
  	if (git_vector_init(&diff->deltas, 0, git_diff_delta__cmp) < 0 ||
  		git_pool_init(&diff->pool, 1, 0) < 0) {
  		git_diff_list_free(diff);
  		return NULL;
  	}
  
  	/* Use case-insensitive compare if either iterator has
  	 * the ignore_case bit set */
  	if (!git_iterator_ignore_case(old_iter) &&
  		!git_iterator_ignore_case(new_iter)) {
  		diff->opts.flags &= ~GIT_DIFF_DELTAS_ARE_ICASE;
  
  		diff->strcomp    = git__strcmp;
  		diff->strncomp   = git__strncmp;
  		diff->pfxcomp    = git__prefixcmp;
  		diff->entrycomp  = git_index_entry__cmp;
  	} else {
  		diff->opts.flags |= GIT_DIFF_DELTAS_ARE_ICASE;
  
  		diff->strcomp    = git__strcasecmp;
  		diff->strncomp   = git__strncasecmp;
  		diff->pfxcomp    = git__prefixcmp_icase;
  		diff->entrycomp  = git_index_entry__cmp_icase;
  	}
  
  	return diff;
  }
  
  static int diff_list_apply_options(
  	git_diff_list *diff,
  	const git_diff_options *opts)
  {
  	git_config *cfg;
  	git_repository *repo = diff->repo;
  	git_pool *pool = &diff->pool;
  	int val;
  
  	if (opts) {
  		/* copy user options (except case sensitivity info from iterators) */
  		bool icase = DIFF_FLAG_IS_SET(diff, GIT_DIFF_DELTAS_ARE_ICASE);
  		memcpy(&diff->opts, opts, sizeof(diff->opts));
  		DIFF_FLAG_SET(diff, GIT_DIFF_DELTAS_ARE_ICASE, icase);
  
  		/* initialize pathspec from options */
  		if (git_pathspec_init(&diff->pathspec, &opts->pathspec, pool) < 0)
  			return -1;
  	}
  
  	/* flag INCLUDE_TYPECHANGE_TREES implies INCLUDE_TYPECHANGE */
  	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_INCLUDE_TYPECHANGE_TREES))
  		diff->opts.flags |= GIT_DIFF_INCLUDE_TYPECHANGE;
  
  	/* load config values that affect diff behavior */
  	if (git_repository_config__weakptr(&cfg, repo) < 0)
  		return -1;
  
  	if (!git_repository__cvar(&val, repo, GIT_CVAR_SYMLINKS) && val)
  		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_HAS_SYMLINKS;
  
  	if (!git_repository__cvar(&val, repo, GIT_CVAR_IGNORESTAT) && val)
  		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_ASSUME_UNCHANGED;
  
  	if ((diff->opts.flags & GIT_DIFF_IGNORE_FILEMODE) == 0 &&
  		!git_repository__cvar(&val, repo, GIT_CVAR_FILEMODE) && val)
  		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_TRUST_MODE_BITS;
  
  	if (!git_repository__cvar(&val, repo, GIT_CVAR_TRUSTCTIME) && val)
  		diff->diffcaps = diff->diffcaps | GIT_DIFFCAPS_TRUST_CTIME;
  
  	/* Don't set GIT_DIFFCAPS_USE_DEV - compile time option in core git */
  
  	/* If not given explicit `opts`, check `diff.xyz` configs */
  	if (!opts) {
  		diff->opts.context_lines = config_int(cfg, "diff.context", 3);
  
  		if (config_bool(cfg, "diff.ignoreSubmodules", 0))
  			diff->opts.flags |= GIT_DIFF_IGNORE_SUBMODULES;
  	}
  
  	/* if either prefix is not set, figure out appropriate value */
  	if (!diff->opts.old_prefix || !diff->opts.new_prefix) {
  		const char *use_old = DIFF_OLD_PREFIX_DEFAULT;
  		const char *use_new = DIFF_NEW_PREFIX_DEFAULT;
  
  		if (config_bool(cfg, "diff.noprefix", 0)) {
  			use_old = use_new = "";
  		} else if (config_bool(cfg, "diff.mnemonicprefix", 0)) {
  			use_old = diff_mnemonic_prefix(diff->old_src, true);
  			use_new = diff_mnemonic_prefix(diff->new_src, false);
  		}
  
  		if (!diff->opts.old_prefix)
  			diff->opts.old_prefix = use_old;
  		if (!diff->opts.new_prefix)
  			diff->opts.new_prefix = use_new;
  	}
  
  	/* strdup prefix from pool so we're not dependent on external data */
  	diff->opts.old_prefix = diff_strdup_prefix(pool, diff->opts.old_prefix);
  	diff->opts.new_prefix = diff_strdup_prefix(pool, diff->opts.new_prefix);
  	if (!diff->opts.old_prefix || !diff->opts.new_prefix)
  		return -1;
  
  	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_REVERSE)) {
  		const char *swap = diff->opts.old_prefix;
  		diff->opts.old_prefix = diff->opts.new_prefix;
  		diff->opts.new_prefix = swap;
  	}
  
  	return 0;
  }
  
  static void diff_list_free(git_diff_list *diff)
  {
  	git_diff_delta *delta;
  	unsigned int i;
  
  	git_vector_foreach(&diff->deltas, i, delta) {
  		git__free(delta);
  		diff->deltas.contents[i] = NULL;
  	}
  	git_vector_free(&diff->deltas);
  
  	git_pathspec_free(&diff->pathspec);
  	git_pool_clear(&diff->pool);
  	git__free(diff);
  }
  
  void git_diff_list_free(git_diff_list *diff)
  {
  	if (!diff)
  		return;
  
  	GIT_REFCOUNT_DEC(diff, diff_list_free);
  }
  
  void git_diff_list_addref(git_diff_list *diff)
  {
  	GIT_REFCOUNT_INC(diff);
  }
  
  int git_diff__oid_for_file(
  	git_repository *repo,
  	const char *path,
  	uint16_t  mode,
  	git_off_t size,
  	git_oid *oid)
  {
  	int result = 0;
  	git_buf full_path = GIT_BUF_INIT;
  
  	if (git_buf_joinpath(
  		&full_path, git_repository_workdir(repo), path) < 0)
  		return -1;
  
  	if (!mode) {
  		struct stat st;
  
  		if (p_stat(path, &st) < 0) {
  			giterr_set(GITERR_OS, "Could not stat '%s'", path);
  			result = -1;
  			goto cleanup;
  		}
  
  		mode = st.st_mode;
  		size = st.st_size;
  	}
  
  	/* calculate OID for file if possible */
  	if (S_ISGITLINK(mode)) {
  		git_submodule *sm;
  		const git_oid *sm_oid;
  
  		if (!git_submodule_lookup(&sm, repo, path) &&
  			(sm_oid = git_submodule_wd_id(sm)) != NULL)
  			git_oid_cpy(oid, sm_oid);
  		else {
  			/* if submodule lookup failed probably just in an intermediate
  			 * state where some init hasn't happened, so ignore the error
  			 */
  			giterr_clear();
  			memset(oid, 0, sizeof(*oid));
  		}
  	} else if (S_ISLNK(mode)) {
  		result = git_odb__hashlink(oid, full_path.ptr);
  	} else if (!git__is_sizet(size)) {
  		giterr_set(GITERR_OS, "File size overflow (for 32-bits) on '%s'", path);
  		result = -1;
  	} else {
  		git_vector filters = GIT_VECTOR_INIT;
  
  		result = git_filters_load(&filters, repo, path, GIT_FILTER_TO_ODB);
  		if (result >= 0) {
  			int fd = git_futils_open_ro(full_path.ptr);
  			if (fd < 0)
  				result = fd;
  			else {
  				result = git_odb__hashfd_filtered(
  					oid, fd, (size_t)size, GIT_OBJ_BLOB, &filters);
  				p_close(fd);
  			}
  		}
  
  		git_filters_free(&filters);
  	}
  
  cleanup:
  	git_buf_free(&full_path);
  	return result;
  }
  
  typedef struct {
  	git_repository *repo;
  	git_iterator *old_iter;
  	git_iterator *new_iter;
  	const git_index_entry *oitem;
  	const git_index_entry *nitem;
  	git_buf ignore_prefix;
  } diff_in_progress;
  
  #define MODE_BITS_MASK 0000777
  
  static int maybe_modified(
  	git_diff_list *diff,
  	diff_in_progress *info)
  {
  	git_oid noid, *use_noid = NULL;
  	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_TYPE_WORKDIR);
  	const char *matched_pathspec;
  
  	if (!git_pathspec_match_path(
  			&diff->pathspec, oitem->path,
  			DIFF_FLAG_IS_SET(diff, GIT_DIFF_DISABLE_PATHSPEC_MATCH),
  			DIFF_FLAG_IS_SET(diff, GIT_DIFF_DELTAS_ARE_ICASE),
  			&matched_pathspec))
  		return 0;
  
  	/* 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);
  
  	/* support "assume unchanged" (poorly, b/c we still stat everything) */
  	if ((diff->diffcaps & GIT_DIFFCAPS_ASSUME_UNCHANGED) != 0)
  		status = (oitem->flags_extended & GIT_IDXENTRY_INTENT_TO_ADD) ?
  			GIT_DELTA_MODIFIED : GIT_DELTA_UNMODIFIED;
  
  	/* support "skip worktree" index bit */
  	else if ((oitem->flags_extended & GIT_IDXENTRY_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 (diff_delta__from_one(diff, GIT_DELTA_DELETED, oitem) < 0 ||
  				diff_delta__from_one(diff, GIT_DELTA_ADDED, nitem) < 0)
  				return -1;
  			return 0;
  		}
  	}
  
  	/* if oids and modes match, then file is unmodified */
  	else if (git_oid_equal(&oitem->oid, &nitem->oid) && omode == nmode)
  		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_iszero(&nitem->oid) && new_is_workdir) {
  		/* TODO: add check against index file st_mtime to avoid racy-git */
  
  		/* if the stat data looks exactly alike, then assume the same */
  		if (omode == nmode &&
  			oitem->file_size == nitem->file_size &&
  			(!(diff->diffcaps & GIT_DIFFCAPS_TRUST_CTIME) ||
  			 (oitem->ctime.seconds == nitem->ctime.seconds)) &&
  			oitem->mtime.seconds == nitem->mtime.seconds &&
  			(!(diff->diffcaps & GIT_DIFFCAPS_USE_DEV) ||
  			 (oitem->dev == nitem->dev)) &&
  			oitem->ino == nitem->ino &&
  			oitem->uid == nitem->uid &&
  			oitem->gid == nitem->gid)
  			status = GIT_DELTA_UNMODIFIED;
  
  		else if (S_ISGITLINK(nmode)) {
  			int err;
  			git_submodule *sub;
  
  			if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_IGNORE_SUBMODULES))
  				status = GIT_DELTA_UNMODIFIED;
  			else if ((err = git_submodule_lookup(&sub, diff->repo, nitem->path)) < 0) {
  				if (err == GIT_EEXISTS)
  					status = GIT_DELTA_UNMODIFIED;
  				else
  					return err;
  			} else if (git_submodule_ignore(sub) == GIT_SUBMODULE_IGNORE_ALL)
  				status = GIT_DELTA_UNMODIFIED;
  			else {
  				unsigned int sm_status = 0;
  				if (git_submodule_status(&sm_status, sub) < 0)
  					return -1;
  
  				/* check IS_WD_UNMODIFIED because this case is only used
  				 * when the new side of the diff is the working directory
  				 */
  				status = GIT_SUBMODULE_STATUS_IS_WD_UNMODIFIED(sm_status)
  						 ? GIT_DELTA_UNMODIFIED : GIT_DELTA_MODIFIED;
  
  				/* grab OID while we are here */
  				if (git_oid_iszero(&nitem->oid)) {
  					const git_oid *sm_oid = git_submodule_wd_id(sub);
  					if (sm_oid != NULL) {
  						git_oid_cpy(&noid, sm_oid);
  						use_noid = &noid;
  					}
  				}
  			}
  		}
  	}
  
  	/* 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 (status != GIT_DELTA_UNMODIFIED && git_oid_iszero(&nitem->oid)) {
  		if (!use_noid) {
  			if (git_diff__oid_for_file(diff->repo,
  					nitem->path, nitem->mode, nitem->file_size, &noid) < 0)
  				return -1;
  			use_noid = &noid;
  		}
  
  		/* 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->oid, use_noid))
  			status = GIT_DELTA_UNMODIFIED;
  	}
  
  	return diff_delta__from_two(
  		diff, status, oitem, omode, nitem, nmode, use_noid, matched_pathspec);
  }
  
  static bool entry_is_prefixed(
  	git_diff_list *diff,
  	const git_index_entry *item,
  	const git_index_entry *prefix_item)
  {
  	size_t pathlen;
  
  	if (!item || diff->pfxcomp(item->path, prefix_item->path) != 0)
  		return false;
  
  	pathlen = strlen(prefix_item->path);
  
  	return (prefix_item->path[pathlen - 1] == '/' ||
  			item->path[pathlen] == '\0' ||
  			item->path[pathlen] == '/');
  }
  
  static int diff_scan_inside_untracked_dir(
  	git_diff_list *diff, diff_in_progress *info, git_delta_t *delta_type)
  {
  	int error = 0;
  	git_buf base = GIT_BUF_INIT;
  	bool is_ignored;
  
  	*delta_type = GIT_DELTA_IGNORED;
  	git_buf_sets(&base, info->nitem->path);
  
  	/* advance into untracked directory */
  	if ((error = git_iterator_advance_into(&info->nitem, info->new_iter)) < 0) {
  
  		/* skip ahead if empty */
  		if (error == GIT_ENOTFOUND) {
  			giterr_clear();
  			error = git_iterator_advance(&info->nitem, info->new_iter);
  		}
  
  		return error;
  	}
  
  	/* look for actual untracked file */
  	while (!diff->pfxcomp(info->nitem->path, git_buf_cstr(&base))) {
  		is_ignored = git_iterator_current_is_ignored(info->new_iter);
  
  		/* need to recurse into non-ignored directories */
  		if (!is_ignored && S_ISDIR(info->nitem->mode)) {
  			if ((error = git_iterator_advance_into(
  					 &info->nitem, info->new_iter)) < 0)
  				break;
  			continue;
  		}
  
  		/* found a non-ignored item - treat parent dir as untracked */
  		if (!is_ignored) {
  			*delta_type = GIT_DELTA_UNTRACKED;
  			break;
  		}
  
  		if ((error = git_iterator_advance(&info->nitem, info->new_iter)) < 0)
  			break;
  	}
  
  	/* finish off scan */
  	while (!diff->pfxcomp(info->nitem->path, git_buf_cstr(&base))) {
  		if ((error = git_iterator_advance(&info->nitem, info->new_iter)) < 0)
  			break;
  	}
  
  	git_buf_free(&base);
  
  	return error;
  }
  
  static int handle_unmatched_new_item(
  	git_diff_list *diff, diff_in_progress *info)
  {
  	int error = 0;
  	const git_index_entry *nitem = info->nitem;
  	git_delta_t delta_type = GIT_DELTA_UNTRACKED;
  	bool contains_oitem;
  
  	/* check if this is a prefix of the other side */
  	contains_oitem = entry_is_prefixed(diff, info->oitem, nitem);
  
  	/* check if this is contained in an ignored parent directory */
  	if (git_buf_len(&info->ignore_prefix)) {
  		if (diff->pfxcomp(nitem->path, git_buf_cstr(&info->ignore_prefix)) == 0)
  			delta_type = GIT_DELTA_IGNORED;
  		else
  			git_buf_clear(&info->ignore_prefix);
  	}
  
  	if (S_ISDIR(nitem->mode)) {
  		bool recurse_into_dir = contains_oitem;
  
  		/* if not already inside an ignored dir, check if this is ignored */
  		if (delta_type != GIT_DELTA_IGNORED &&
  			git_iterator_current_is_ignored(info->new_iter)) {
  			delta_type = GIT_DELTA_IGNORED;
  			git_buf_sets(&info->ignore_prefix, nitem->path);
  		}
  
  		/* check if user requests recursion into this type of dir */
  		recurse_into_dir = contains_oitem ||
  			(delta_type == GIT_DELTA_UNTRACKED &&
  			 DIFF_FLAG_IS_SET(diff, GIT_DIFF_RECURSE_UNTRACKED_DIRS)) ||
  			(delta_type == GIT_DELTA_IGNORED &&
  			 DIFF_FLAG_IS_SET(diff, GIT_DIFF_RECURSE_IGNORED_DIRS));
  
  		/* do not advance into directories that contain a .git file */
  		if (recurse_into_dir) {
  			git_buf *full = NULL;
  			if (git_iterator_current_workdir_path(&full, info->new_iter) < 0)
  				return -1;
  			if (full && git_path_contains_dir(full, DOT_GIT))
  				recurse_into_dir = false;
  		}
  
  		/* still have to look into untracked directories to match core git -
  		 * with no untracked files, directory is treated as ignored
  		 */
  		if (!recurse_into_dir &&
  			delta_type == GIT_DELTA_UNTRACKED &&
  			DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_FAST_UNTRACKED_DIRS))
  		{
  			git_diff_delta *last;
  
  			/* attempt to insert record for this directory */
  			if ((error = diff_delta__from_one(diff, delta_type, nitem)) < 0)
  				return error;
  
  			/* if delta wasn't created (because of rules), just skip ahead */
  			last = diff_delta__last_for_item(diff, nitem);
  			if (!last)
  				return git_iterator_advance(&info->nitem, info->new_iter);
  
  			/* iterate into dir looking for an actual untracked file */
  			if (diff_scan_inside_untracked_dir(diff, info, &delta_type) < 0)
  				return -1;
  
  			/* it iteration changed delta type, the update the record */
  			if (delta_type == GIT_DELTA_IGNORED) {
  				last->status = GIT_DELTA_IGNORED;
  
  				/* remove the record if we don't want ignored records */
  				if (DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_INCLUDE_IGNORED)) {
  					git_vector_pop(&diff->deltas);
  					git__free(last);
  				}
  			}
  
  			return 0;
  		}
  
  		/* try to advance into directory if necessary */
  		if (recurse_into_dir) {
  			error = git_iterator_advance_into(&info->nitem, info->new_iter);
  
  			/* if real error or no error, proceed with iteration */
  			if (error != GIT_ENOTFOUND)
  				return error;
  			giterr_clear();
  
  			/* if directory is empty, can't advance into it, so either skip
  			 * it or ignore it
  			 */
  			if (contains_oitem)
  				return git_iterator_advance(&info->nitem, info->new_iter);
  			delta_type = GIT_DELTA_IGNORED;
  		}
  	}
  
  	/* In core git, the next two checks are effectively reversed --
  	 * i.e. when an file contained in an ignored directory is explicitly
  	 * ignored, it shows up as an ignored file in the diff list, even though
  	 * other untracked files in the same directory are skipped completely.
  	 *
  	 * To me, this seems odd.  If the directory is ignored and the file is
  	 * untracked, we should skip it consistently, regardless of whether it
  	 * happens to match a pattern in the ignore file.
  	 *
  	 * To match the core git behavior, reverse the following two if checks
  	 * so that individual file ignores are checked before container
  	 * directory exclusions are used to skip the file.
  	 */
  	else if (delta_type == GIT_DELTA_IGNORED &&
  		DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_RECURSE_IGNORED_DIRS))
  		/* item contained in ignored directory, so skip over it */
  		return git_iterator_advance(&info->nitem, info->new_iter);
  
  	else if (git_iterator_current_is_ignored(info->new_iter))
  		delta_type = GIT_DELTA_IGNORED;
  
  	else if (info->new_iter->type != GIT_ITERATOR_TYPE_WORKDIR)
  		delta_type = GIT_DELTA_ADDED;
  
  	/* Actually create the record for this item if necessary */
  	if ((error = diff_delta__from_one(diff, delta_type, nitem)) < 0)
  		return error;
  
  	/* If user requested TYPECHANGE records, then check for that instead of
  	 * just generating an ADDED/UNTRACKED record
  	 */
  	if (delta_type != GIT_DELTA_IGNORED &&
  		DIFF_FLAG_IS_SET(diff, GIT_DIFF_INCLUDE_TYPECHANGE_TREES) &&
  		contains_oitem)
  	{
  		/* this entry was prefixed with a tree - make TYPECHANGE */
  		git_diff_delta *last = diff_delta__last_for_item(diff, nitem);
  		if (last) {
  			last->status = GIT_DELTA_TYPECHANGE;
  			last->old_file.mode = GIT_FILEMODE_TREE;
  		}
  	}
  
  	return git_iterator_advance(&info->nitem, info->new_iter);
  }
  
  static int handle_unmatched_old_item(
  	git_diff_list *diff, diff_in_progress *info)
  {
  	int error = diff_delta__from_one(diff, GIT_DELTA_DELETED, info->oitem);
  	if (error < 0)
  		return error;
  
  	/* if we are generating TYPECHANGE records then check for that
  	 * instead of just generating a DELETE record
  	 */
  	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_INCLUDE_TYPECHANGE_TREES) &&
  		entry_is_prefixed(diff, info->nitem, info->oitem))
  	{
  		/* this entry has become a tree! convert to TYPECHANGE */
  		git_diff_delta *last = diff_delta__last_for_item(diff, info->oitem);
  		if (last) {
  			last->status = GIT_DELTA_TYPECHANGE;
  			last->new_file.mode = GIT_FILEMODE_TREE;
  		}
  
  		/* If new_iter is a workdir iterator, then this situation
  		 * will certainly be followed by a series of untracked items.
  		 * Unless RECURSE_UNTRACKED_DIRS is set, skip over them...
  		 */
  		if (S_ISDIR(info->nitem->mode) &&
  			DIFF_FLAG_ISNT_SET(diff, GIT_DIFF_RECURSE_UNTRACKED_DIRS))
  			return git_iterator_advance(&info->nitem, info->new_iter);
  	}
  
  	return git_iterator_advance(&info->oitem, info->old_iter);
  }
  
  static int handle_matched_item(
  	git_diff_list *diff, diff_in_progress *info)
  {
  	int error = 0;
  
  	if (!(error = maybe_modified(diff, info)) &&
  		!(error = git_iterator_advance(&info->oitem, info->old_iter)))
  		error = git_iterator_advance(&info->nitem, info->new_iter);
  
  	return error;
  }
  
  int git_diff__from_iterators(
  	git_diff_list **diff_ptr,
  	git_repository *repo,
  	git_iterator *old_iter,
  	git_iterator *new_iter,
  	const git_diff_options *opts)
  {
  	int error = 0;
  	diff_in_progress info;
  	git_diff_list *diff;
  
  	*diff_ptr = NULL;
  
  	diff = diff_list_alloc(repo, old_iter, new_iter);
  	GITERR_CHECK_ALLOC(diff);
  
  	info.repo = repo;
  	info.old_iter = old_iter;
  	info.new_iter = new_iter;
  	git_buf_init(&info.ignore_prefix, 0);
  
  	/* make iterators have matching icase behavior */
  	if (DIFF_FLAG_IS_SET(diff, GIT_DIFF_DELTAS_ARE_ICASE)) {
  		if (!(error = git_iterator_set_ignore_case(old_iter, true)))
  			error = git_iterator_set_ignore_case(new_iter, true);
  	}
  
  	/* finish initialization */
  	if (!error &&
  		!(error = diff_list_apply_options(diff, opts)) &&
  		!(error = git_iterator_current(&info.oitem, old_iter)))
  		error = git_iterator_current(&info.nitem, new_iter);
  
  	/* run iterators building diffs */
  	while (!error && (info.oitem || info.nitem)) {
  		int cmp = info.oitem ?
  			(info.nitem ? diff->entrycomp(info.oitem, info.nitem) : -1) : 1;
  
  		/* create DELETED records for old items not matched in new */
  		if (cmp < 0)
  			error = handle_unmatched_old_item(diff, &info);
  
  		/* create ADDED, TRACKED, or IGNORED records for new items not
  		 * matched in old (and/or descend into directories as needed)
  		 */
  		else if (cmp > 0)
  			error = handle_unmatched_new_item(diff, &info);
  
  		/* otherwise item paths match, so create MODIFIED record
  		 * (or ADDED and DELETED pair if type changed)
  		 */
  		else
  			error = handle_matched_item(diff, &info);
  	}
  
  	if (!error)
  		*diff_ptr = diff;
  	else
  		git_diff_list_free(diff);
  
  	git_buf_free(&info.ignore_prefix);
  
  	return error;
  }
  
  #define DIFF_FROM_ITERATORS(MAKE_FIRST, MAKE_SECOND) do { \
  	git_iterator *a = NULL, *b = NULL; \
  	char *pfx = opts ? git_pathspec_prefix(&opts->pathspec) : NULL; \
  	GITERR_CHECK_VERSION(opts, GIT_DIFF_OPTIONS_VERSION, "git_diff_options"); \
  	if (!(error = MAKE_FIRST) && !(error = MAKE_SECOND)) \
  		error = git_diff__from_iterators(diff, repo, a, b, opts); \
  	git__free(pfx); git_iterator_free(a); git_iterator_free(b); \
  } while (0)
  
  int git_diff_tree_to_tree(
  	git_diff_list **diff,
  	git_repository *repo,
  	git_tree *old_tree,
  	git_tree *new_tree,
  	const git_diff_options *opts)
  {
  	int error = 0;
  	git_iterator_flag_t iflag = GIT_ITERATOR_DONT_IGNORE_CASE;
  
  	assert(diff && repo);
  
  	/* for tree to tree diff, be case sensitive even if the index is
  	 * currently case insensitive, unless the user explicitly asked
  	 * for case insensitivity
  	 */
  	if (opts && (opts->flags & GIT_DIFF_DELTAS_ARE_ICASE) != 0)
  		iflag = GIT_ITERATOR_IGNORE_CASE;
  
  	DIFF_FROM_ITERATORS(
  		git_iterator_for_tree(&a, old_tree, iflag, pfx, pfx),
  		git_iterator_for_tree(&b, new_tree, iflag, pfx, pfx)
  	);
  
  	return error;
  }
  
  int git_diff_tree_to_index(
  	git_diff_list **diff,
  	git_repository *repo,
  	git_tree *old_tree,
  	git_index *index,
  	const git_diff_options *opts)
  {
  	int error = 0;
  
  	assert(diff && repo);
  
  	if (!index && (error = git_repository_index__weakptr(&index, repo)) < 0)
  		return error;
  
  	DIFF_FROM_ITERATORS(
  		git_iterator_for_tree(&a, old_tree, 0, pfx, pfx),
  		git_iterator_for_index(&b, index, 0, pfx, pfx)
  	);
  
  	return error;
  }
  
  int git_diff_index_to_workdir(
  	git_diff_list **diff,
  	git_repository *repo,
  	git_index *index,
  	const git_diff_options *opts)
  {
  	int error = 0;
  
  	assert(diff && repo);
  
  	if (!index && (error = git_repository_index__weakptr(&index, repo)) < 0)
  		return error;
  
  	DIFF_FROM_ITERATORS(
  		git_iterator_for_index(&a, index, 0, pfx, pfx),
  		git_iterator_for_workdir(
  			&b, repo, GIT_ITERATOR_DONT_AUTOEXPAND, pfx, pfx)
  	);
  
  	return error;
  }
  
  
  int git_diff_tree_to_workdir(
  	git_diff_list **diff,
  	git_repository *repo,
  	git_tree *old_tree,
  	const git_diff_options *opts)
  {
  	int error = 0;
  
  	assert(diff && repo);
  
  	DIFF_FROM_ITERATORS(
  		git_iterator_for_tree(&a, old_tree, 0, pfx, pfx),
  		git_iterator_for_workdir(
  			&b, repo, GIT_ITERATOR_DONT_AUTOEXPAND, pfx, pfx)
  	);
  
  	return error;
  }
  

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