thodg/libgit2/src/diff.c

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• Hash : 66142ae0
  Author :
  Date : 2012-03-22T10:44:36
  

  New status fixes This adds support for roughly-right tracking of submodules (although it does not recurse into submodules to detect internal modifications a la core git), and it adds support for including unmodified files in diff iteration if requested.

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• src/diff.c

• /*
   * Copyright (C) 2012 the libgit2 contributors
   *
   * 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 "git2/diff.h"
  #include "diff.h"
  #include "fileops.h"
  
  static void diff_delta__free(git_diff_delta *delta)
  {
  	if (!delta)
  		return;
  
  	if (delta->new.flags & GIT_DIFF_FILE_FREE_PATH) {
  		git__free((char *)delta->new.path);
  		delta->new.path = NULL;
  	}
  
  	if (delta->old.flags & GIT_DIFF_FILE_FREE_PATH) {
  		git__free((char *)delta->old.path);
  		delta->old.path = NULL;
  	}
  
  	git__free(delta);
  }
  
  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.path = git__strdup(path);
  	if (delta->old.path == NULL) {
  		git__free(delta);
  		return NULL;
  	}
  	delta->old.flags |= GIT_DIFF_FILE_FREE_PATH;
  	delta->new.path = delta->old.path;
  
  	if (diff->opts.flags & 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 git_diff_delta *diff_delta__dup(const git_diff_delta *d)
  {
  	git_diff_delta *delta = git__malloc(sizeof(git_diff_delta));
  	if (!delta)
  		return NULL;
  
  	memcpy(delta, d, sizeof(git_diff_delta));
  
  	delta->old.path = git__strdup(d->old.path);
  	if (delta->old.path == NULL) {
  		git__free(delta);
  		return NULL;
  	}
  	delta->old.flags |= GIT_DIFF_FILE_FREE_PATH;
  
  	if (d->new.path != d->old.path) {
  		delta->new.path = git__strdup(d->new.path);
  		if (delta->new.path == NULL) {
  			git__free(delta->old.path);
  			git__free(delta);
  			return NULL;
  		}
  		delta->new.flags |= GIT_DIFF_FILE_FREE_PATH;
  	} else {
  		delta->new.path = delta->old.path;
  		delta->new.flags &= ~GIT_DIFF_FILE_FREE_PATH;
  	}
  
  	return delta;
  }
  
  static git_diff_delta *diff_delta__merge_like_cgit(
  	const git_diff_delta *a, const git_diff_delta *b)
  {
  	git_diff_delta *dup = diff_delta__dup(a);
  	if (!dup)
  		return NULL;
  
  	if (git_oid_cmp(&dup->new.oid, &b->new.oid) == 0)
  		return dup;
  
  	git_oid_cpy(&dup->new.oid, &b->new.oid);
  
  	dup->new.mode = b->new.mode;
  	dup->new.size = b->new.size;
  	dup->new.flags =
  		(dup->new.flags & GIT_DIFF_FILE_FREE_PATH) |
  		(b->new.flags & ~GIT_DIFF_FILE_FREE_PATH);
  
  	/* Emulate C git for merging two diffs (a la 'git diff <sha>').
  	 *
  	 * When C git does a diff between the work dir and a tree, it actually
  	 * diffs with the index but uses the workdir contents.  This emulates
  	 * those choices so we can emulate the type of diff.
  	 */
  	if (git_oid_cmp(&dup->old.oid, &dup->new.oid) == 0) {
  		if (dup->status == GIT_DELTA_DELETED)
  			/* preserve pending delete info */;
  		else if (b->status == GIT_DELTA_UNTRACKED ||
  				 b->status == GIT_DELTA_IGNORED)
  			dup->status = b->status;
  		else
  			dup->status = GIT_DELTA_UNMODIFIED;
  	}
  	else if (dup->status == GIT_DELTA_UNMODIFIED ||
  			 b->status == GIT_DELTA_DELETED)
  		dup->status = b->status;
  
  	return dup;
  }
  
  static int diff_delta__from_one(
  	git_diff_list *diff,
  	git_delta_t   status,
  	const git_index_entry *entry)
  {
  	git_diff_delta *delta;
  
  	if (status == GIT_DELTA_IGNORED &&
  		(diff->opts.flags & GIT_DIFF_INCLUDE_IGNORED) == 0)
  		return 0;
  
  	if (status == GIT_DELTA_UNTRACKED &&
  		(diff->opts.flags & GIT_DIFF_INCLUDE_UNTRACKED) == 0)
  		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.mode = entry->mode;
  		delta->old.size = entry->file_size;
  		git_oid_cpy(&delta->old.oid, &entry->oid);
  	} else /* ADDED, IGNORED, UNTRACKED */ {
  		delta->new.mode = entry->mode;
  		delta->new.size = entry->file_size;
  		git_oid_cpy(&delta->new.oid, &entry->oid);
  	}
  
  	delta->old.flags |= GIT_DIFF_FILE_VALID_OID;
  	delta->new.flags |= GIT_DIFF_FILE_VALID_OID;
  
  	if (git_vector_insert(&diff->deltas, delta) < 0) {
  		diff_delta__free(delta);
  		return -1;
  	}
  
  	return 0;
  }
  
  static int diff_delta__from_two(
  	git_diff_list *diff,
  	git_delta_t   status,
  	const git_index_entry *old,
  	const git_index_entry *new,
  	git_oid *new_oid)
  {
  	git_diff_delta *delta;
  
  	if (status == GIT_DELTA_UNMODIFIED &&
  		(diff->opts.flags & GIT_DIFF_INCLUDE_UNMODIFIED) == 0)
  		return 0;
  
  	if ((diff->opts.flags & GIT_DIFF_REVERSE) != 0) {
  		const git_index_entry *temp = old;
  		old = new;
  		new = temp;
  	}
  
  	delta = diff_delta__alloc(diff, status, old->path);
  	GITERR_CHECK_ALLOC(delta);
  
  	delta->old.mode = old->mode;
  	git_oid_cpy(&delta->old.oid, &old->oid);
  	delta->old.flags |= GIT_DIFF_FILE_VALID_OID;
  
  	delta->new.mode = new->mode;
  	git_oid_cpy(&delta->new.oid, new_oid ? new_oid : &new->oid);
  	if (new_oid || !git_oid_iszero(&new->oid))
  		delta->new.flags |= GIT_DIFF_FILE_VALID_OID;
  
  	if (git_vector_insert(&diff->deltas, delta) < 0) {
  		diff_delta__free(delta);
  		return -1;
  	}
  
  	return 0;
  }
  
  #define DIFF_SRC_PREFIX_DEFAULT "a/"
  #define DIFF_DST_PREFIX_DEFAULT "b/"
  
  static char *diff_strdup_prefix(const char *prefix)
  {
  	size_t len = strlen(prefix);
  	char *str = git__malloc(len + 2);
  	if (str != NULL) {
  		memcpy(str, prefix, len + 1);
  		/* append '/' at end if needed */
  		if (len > 0 && str[len - 1] != '/') {
  			str[len] = '/';
  			str[len + 1] = '\0';
  		}
  	}
  	return str;
  }
  
  static int diff_delta__cmp(const void *a, const void *b)
  {
  	const git_diff_delta *da = a, *db = b;
  	int val = strcmp(da->old.path, db->old.path);
  	return val ? val : ((int)da->status - (int)db->status);
  }
  
  static git_diff_list *git_diff_list_alloc(
  	git_repository *repo, const git_diff_options *opts)
  {
  	git_diff_list *diff = git__calloc(1, sizeof(git_diff_list));
  	if (diff == NULL)
  		return NULL;
  
  	diff->repo = repo;
  
  	if (opts == NULL)
  		return diff;
  
  	memcpy(&diff->opts, opts, sizeof(git_diff_options));
  
  	diff->opts.src_prefix = diff_strdup_prefix(
  		opts->src_prefix ? opts->src_prefix : DIFF_SRC_PREFIX_DEFAULT);
  	diff->opts.dst_prefix = diff_strdup_prefix(
  		opts->dst_prefix ? opts->dst_prefix : DIFF_DST_PREFIX_DEFAULT);
  
  	if (!diff->opts.src_prefix || !diff->opts.dst_prefix) {
  		git__free(diff);
  		return NULL;
  	}
  
  	if (diff->opts.flags & GIT_DIFF_REVERSE) {
  		char *swap = diff->opts.src_prefix;
  		diff->opts.src_prefix = diff->opts.dst_prefix;
  		diff->opts.dst_prefix = swap;
  	}
  
  	if (git_vector_init(&diff->deltas, 0, diff_delta__cmp) < 0) {
  		git__free(diff->opts.src_prefix);
  		git__free(diff->opts.dst_prefix);
  		git__free(diff);
  		return NULL;
  	}
  
  	/* TODO: do something safe with the pathspec strarray */
  
  	return diff;
  }
  
  void git_diff_list_free(git_diff_list *diff)
  {
  	git_diff_delta *delta;
  	unsigned int i;
  
  	if (!diff)
  		return;
  
  	git_vector_foreach(&diff->deltas, i, delta) {
  		diff_delta__free(delta);
  		diff->deltas.contents[i] = NULL;
  	}
  	git_vector_free(&diff->deltas);
  	git__free(diff->opts.src_prefix);
  	git__free(diff->opts.dst_prefix);
  	git__free(diff);
  }
  
  static int oid_for_workdir_item(
  	git_repository *repo,
  	const git_index_entry *item,
  	git_oid *oid)
  {
  	int result;
  	git_buf full_path = GIT_BUF_INIT;
  
  	if (git_buf_joinpath(&full_path, git_repository_workdir(repo), item->path) < 0)
  		return -1;
  
  	/* calculate OID for file if possible*/
  	if (S_ISLNK(item->mode))
  		result = git_odb__hashlink(oid, full_path.ptr);
  	else if (!git__is_sizet(item->file_size)) {
  		giterr_set(GITERR_OS, "File size overflow for 32-bit systems");
  		result = -1;
  	} else {
  		int fd = git_futils_open_ro(full_path.ptr);
  		if (fd < 0)
  			result = fd;
  		else {
  			result = git_odb__hashfd(
  				oid, fd, (size_t)item->file_size, GIT_OBJ_BLOB);
  			p_close(fd);
  		}
  	}
  
  	git_buf_free(&full_path);
  
  	return result;
  }
  
  static int maybe_modified(
  	git_iterator *old,
  	const git_index_entry *oitem,
  	git_iterator *new,
  	const git_index_entry *nitem,
  	git_diff_list *diff)
  {
  	git_oid noid, *use_noid = NULL;
  	git_delta_t status = GIT_DELTA_MODIFIED;
  
  	GIT_UNUSED(old);
  
  	/* support "assume unchanged" & "skip worktree" bits */
  	if ((oitem->flags_extended & GIT_IDXENTRY_INTENT_TO_ADD) != 0 ||
  		(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(oitem->mode) != GIT_MODE_TYPE(nitem->mode)) {
  		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_cmp(&oitem->oid, &nitem->oid) == 0 &&
  			oitem->mode == nitem->mode)
  		status = GIT_DELTA_UNMODIFIED;
  
  	/* if we have a workdir item with an unknown oid, check deeper */
  	else if (git_oid_iszero(&nitem->oid) && new->type == GIT_ITERATOR_WORKDIR) {
  		/* if they files look exactly alike, then we'll assume the same */
  		if (oitem->file_size == nitem->file_size &&
  			oitem->ctime.seconds == nitem->ctime.seconds &&
  			oitem->mtime.seconds == nitem->mtime.seconds &&
  			oitem->dev == nitem->dev &&
  			oitem->ino == nitem->ino &&
  			oitem->uid == nitem->uid &&
  			oitem->gid == nitem->gid)
  			status = GIT_DELTA_UNMODIFIED;
  
  		/* TODO? should we do anything special with submodules? */
  		else if (S_ISGITLINK(nitem->mode))
  			status = GIT_DELTA_UNMODIFIED;
  
  		/* TODO: check git attributes so we will not have to read the file
  		 * in if it is marked binary.
  		 */
  
  		else if (oid_for_workdir_item(diff->repo, nitem, &noid) < 0)
  			return -1;
  
  		else if (git_oid_cmp(&oitem->oid, &noid) == 0 &&
  			oitem->mode == nitem->mode)
  			status = GIT_DELTA_UNMODIFIED;
  
  		/* store calculated oid so we don't have to recalc later */
  		use_noid = &noid;
  	}
  
  	return diff_delta__from_two(diff, status, oitem, nitem, use_noid);
  }
  
  static int diff_from_iterators(
  	git_repository *repo,
  	const git_diff_options *opts, /**< can be NULL for defaults */
  	git_iterator *old,
  	git_iterator *new,
  	git_diff_list **diff_ptr)
  {
  	const git_index_entry *oitem, *nitem;
  	char *ignore_prefix = NULL;
  	git_diff_list *diff = git_diff_list_alloc(repo, opts);
  	if (!diff)
  		goto fail;
  
  	diff->old_src = old->type;
  	diff->new_src = new->type;
  
  	if (git_iterator_current(old, &oitem) < 0 ||
  		git_iterator_current(new, &nitem) < 0)
  		goto fail;
  
  	/* run iterators building diffs */
  	while (oitem || nitem) {
  
  		/* create DELETED records for old items not matched in new */
  		if (oitem && (!nitem || strcmp(oitem->path, nitem->path) < 0)) {
  			if (diff_delta__from_one(diff, GIT_DELTA_DELETED, oitem) < 0 ||
  				git_iterator_advance(old, &oitem) < 0)
  				goto fail;
  		}
  
  		/* create ADDED, TRACKED, or IGNORED records for new items not
  		 * matched in old (and/or descend into directories as needed)
  		 */
  		else if (nitem && (!oitem || strcmp(oitem->path, nitem->path) > 0)) {
  			int is_ignored;
  			git_delta_t delta_type = GIT_DELTA_ADDED;
  
  			/* contained in ignored parent directory, so this can be skipped. */
  			if (ignore_prefix != NULL &&
  				git__prefixcmp(nitem->path, ignore_prefix) == 0)
  			{
  				if (git_iterator_advance(new, &nitem) < 0)
  					goto fail;
  				continue;
  			}
  
  			is_ignored = git_iterator_current_is_ignored(new);
  
  			if (S_ISDIR(nitem->mode)) {
  				if (git__prefixcmp(oitem->path, nitem->path) == 0) {
  					if (is_ignored)
  						ignore_prefix = nitem->path;
  					if (git_iterator_advance_into_directory(new, &nitem) < 0)
  						goto fail;
  					continue;
  				}
  				delta_type = GIT_DELTA_UNTRACKED;
  			}
  			else if (is_ignored)
  				delta_type = GIT_DELTA_IGNORED;
  			else if (new->type == GIT_ITERATOR_WORKDIR)
  				delta_type = GIT_DELTA_UNTRACKED;
  
  			if (diff_delta__from_one(diff, delta_type, nitem) < 0 ||
  				git_iterator_advance(new, &nitem) < 0)
  				goto fail;
  		}
  
  		/* otherwise item paths match, so create MODIFIED record
  		 * (or ADDED and DELETED pair if type changed)
  		 */
  		else {
  			assert(oitem && nitem && strcmp(oitem->path, nitem->path) == 0);
  
  			if (maybe_modified(old, oitem, new, nitem, diff) < 0 ||
  				git_iterator_advance(old, &oitem) < 0 ||
  				git_iterator_advance(new, &nitem) < 0)
  				goto fail;
  		}
  	}
  
  	git_iterator_free(old);
  	git_iterator_free(new);
  	*diff_ptr = diff;
  	return 0;
  
  fail:
  	git_iterator_free(old);
  	git_iterator_free(new);
  	git_diff_list_free(diff);
  	*diff_ptr = NULL;
  	return -1;
  }
  
  
  int git_diff_tree_to_tree(
  	git_repository *repo,
  	const git_diff_options *opts, /**< can be NULL for defaults */
  	git_tree *old,
  	git_tree *new,
  	git_diff_list **diff)
  {
  	git_iterator *a = NULL, *b = NULL;
  
  	assert(repo && old && new && diff);
  
  	if (git_iterator_for_tree(repo, old, &a) < 0 ||
  		git_iterator_for_tree(repo, new, &b) < 0)
  		return -1;
  
  	return diff_from_iterators(repo, opts, a, b, diff);
  }
  
  int git_diff_index_to_tree(
  	git_repository *repo,
  	const git_diff_options *opts,
  	git_tree *old,
  	git_diff_list **diff)
  {
  	git_iterator *a = NULL, *b = NULL;
  
  	assert(repo && old && diff);
  
  	if (git_iterator_for_tree(repo, old, &a) < 0 ||
  		git_iterator_for_index(repo, &b) < 0)
  		return -1;
  
  	return diff_from_iterators(repo, opts, a, b, diff);
  }
  
  int git_diff_workdir_to_index(
  	git_repository *repo,
  	const git_diff_options *opts,
  	git_diff_list **diff)
  {
  	git_iterator *a = NULL, *b = NULL;
  
  	assert(repo && diff);
  
  	if (git_iterator_for_index(repo, &a) < 0 ||
  		git_iterator_for_workdir(repo, &b) < 0)
  		return -1;
  
  	return diff_from_iterators(repo, opts, a, b, diff);
  }
  
  
  int git_diff_workdir_to_tree(
  	git_repository *repo,
  	const git_diff_options *opts,
  	git_tree *old,
  	git_diff_list **diff)
  {
  	git_iterator *a = NULL, *b = NULL;
  
  	assert(repo && old && diff);
  
  	if (git_iterator_for_tree(repo, old, &a) < 0 ||
  		git_iterator_for_workdir(repo, &b) < 0)
  		return -1;
  
  	return diff_from_iterators(repo, opts, a, b, diff);
  }
  
  int git_diff_merge(
  	git_diff_list *onto,
  	const git_diff_list *from)
  {
  	int error = 0;
  	git_vector onto_new;
  	git_diff_delta *delta, *o;
  	const git_diff_delta *f;
  	unsigned int i;
  
  	if (git_vector_init(&onto_new, onto->deltas.length, diff_delta__cmp) < 0)
  		return -1;
  
  	GIT_DIFF_COITERATE(
  		onto, from, o, f,
  		delta = diff_delta__dup(o),
  		delta = diff_delta__dup(f),
  		delta = diff_delta__merge_like_cgit(o, f),
  		if ((error = !delta ? -1 : git_vector_insert(&onto_new, delta)) < 0)
  			break;
  		);
  
  	if (error == 0) {
  		git_vector_swap(&onto->deltas, &onto_new);
  		onto->new_src = from->new_src;
  	}
  
  	git_vector_foreach(&onto_new, i, delta)
  		diff_delta__free(delta);
  	git_vector_free(&onto_new);
  
  	return error;
  }
  
  

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