thodg/libgit2/src/diff_output.c

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• Hash : a8122b5d
  Author :
  Date : 2012-11-21T15:39:03
  

  Fix warnings on Win64 build

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• src/diff_output.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/attr.h"
  #include "git2/oid.h"
  #include "git2/submodule.h"
  #include "diff_output.h"
  #include <ctype.h>
  #include "fileops.h"
  #include "filter.h"
  
  static int read_next_int(const char **str, int *value)
  {
  	const char *scan = *str;
  	int v = 0, digits = 0;
  	/* find next digit */
  	for (scan = *str; *scan && !isdigit(*scan); scan++);
  	/* parse next number */
  	for (; isdigit(*scan); scan++, digits++)
  		v = (v * 10) + (*scan - '0');
  	*str = scan;
  	*value = v;
  	return (digits > 0) ? 0 : -1;
  }
  
  static int parse_hunk_header(git_diff_range *range, const char *header)
  {
  	/* expect something of the form "@@ -%d[,%d] +%d[,%d] @@" */
  	if (*header != '@')
  		return -1;
  	if (read_next_int(&header, &range->old_start) < 0)
  		return -1;
  	if (*header == ',') {
  		if (read_next_int(&header, &range->old_lines) < 0)
  			return -1;
  	} else
  		range->old_lines = 1;
  	if (read_next_int(&header, &range->new_start) < 0)
  		return -1;
  	if (*header == ',') {
  		if (read_next_int(&header, &range->new_lines) < 0)
  			return -1;
  	} else
  		range->new_lines = 1;
  	if (range->old_start < 0 || range->new_start < 0)
  		return -1;
  
  	return 0;
  }
  
  #define KNOWN_BINARY_FLAGS (GIT_DIFF_FILE_BINARY|GIT_DIFF_FILE_NOT_BINARY)
  #define NOT_BINARY_FLAGS   (GIT_DIFF_FILE_NOT_BINARY|GIT_DIFF_FILE_NO_DATA)
  
  static int update_file_is_binary_by_attr(
  	git_repository *repo, git_diff_file *file)
  {
  	const char *value;
  
  	/* because of blob diffs, cannot assume path is set */
  	if (!file->path || !strlen(file->path))
  		return 0;
  
  	if (git_attr_get(&value, repo, 0, file->path, "diff") < 0)
  		return -1;
  
  	if (GIT_ATTR_FALSE(value))
  		file->flags |= GIT_DIFF_FILE_BINARY;
  	else if (GIT_ATTR_TRUE(value))
  		file->flags |= GIT_DIFF_FILE_NOT_BINARY;
  	/* otherwise leave file->flags alone */
  
  	return 0;
  }
  
  static void update_delta_is_binary(git_diff_delta *delta)
  {
  	if ((delta->old_file.flags & GIT_DIFF_FILE_BINARY) != 0 ||
  		(delta->new_file.flags & GIT_DIFF_FILE_BINARY) != 0)
  		delta->binary = 1;
  
  	else if ((delta->old_file.flags & NOT_BINARY_FLAGS) != 0 &&
  			 (delta->new_file.flags & NOT_BINARY_FLAGS) != 0)
  		delta->binary = 0;
  
  	/* otherwise leave delta->binary value untouched */
  }
  
  static int diff_delta_is_binary_by_attr(
  	diff_context *ctxt, git_diff_patch *patch)
  {
  	int error = 0, mirror_new;
  	git_diff_delta *delta = patch->delta;
  
  	delta->binary = -1;
  
  	/* make sure files are conceivably mmap-able */
  	if ((git_off_t)((size_t)delta->old_file.size) != delta->old_file.size ||
  		(git_off_t)((size_t)delta->new_file.size) != delta->new_file.size)
  	{
  		delta->old_file.flags |= GIT_DIFF_FILE_BINARY;
  		delta->new_file.flags |= GIT_DIFF_FILE_BINARY;
  		delta->binary = 1;
  		return 0;
  	}
  
  	/* check if user is forcing us to text diff these files */
  	if (ctxt->opts && (ctxt->opts->flags & GIT_DIFF_FORCE_TEXT) != 0) {
  		delta->old_file.flags |= GIT_DIFF_FILE_NOT_BINARY;
  		delta->new_file.flags |= GIT_DIFF_FILE_NOT_BINARY;
  		delta->binary = 0;
  		return 0;
  	}
  
  	/* check diff attribute +, -, or 0 */
  	if (update_file_is_binary_by_attr(ctxt->repo, &delta->old_file) < 0)
  		return -1;
  
  	mirror_new = (delta->new_file.path == delta->old_file.path ||
  		ctxt->diff->strcomp(delta->new_file.path, delta->old_file.path) == 0);
  	if (mirror_new)
  		delta->new_file.flags |= (delta->old_file.flags & KNOWN_BINARY_FLAGS);
  	else
  		error = update_file_is_binary_by_attr(ctxt->repo, &delta->new_file);
  
  	update_delta_is_binary(delta);
  
  	return error;
  }
  
  static int diff_delta_is_binary_by_content(
  	diff_context *ctxt, git_diff_delta *delta, git_diff_file *file, git_map *map)
  {
  	git_buf search;
  
  	GIT_UNUSED(ctxt);
  
  	if ((file->flags & KNOWN_BINARY_FLAGS) == 0) {
  		search.ptr  = map->data;
  		search.size = min(map->len, 4000);
  
  		if (git_buf_is_binary(&search))
  			file->flags |= GIT_DIFF_FILE_BINARY;
  		else
  			file->flags |= GIT_DIFF_FILE_NOT_BINARY;
  	}
  
  	update_delta_is_binary(delta);
  
  	return 0;
  }
  
  static int diff_delta_is_binary_by_size(
  	diff_context *ctxt, git_diff_delta *delta, git_diff_file *file)
  {
  	git_off_t threshold = MAX_DIFF_FILESIZE;
  
  	if ((file->flags & KNOWN_BINARY_FLAGS) != 0)
  		return 0;
  
  	if (ctxt && ctxt->opts) {
  		if (ctxt->opts->max_size < 0)
  			return 0;
  
  		if (ctxt->opts->max_size > 0)
  			threshold = ctxt->opts->max_size;
  	}
  
  	if (file->size > threshold)
  		file->flags |= GIT_DIFF_FILE_BINARY;
  
  	update_delta_is_binary(delta);
  
  	return 0;
  }
  
  static void setup_xdiff_options(
  	const git_diff_options *opts, xdemitconf_t *cfg, xpparam_t *param)
  {
  	memset(cfg, 0, sizeof(xdemitconf_t));
  	memset(param, 0, sizeof(xpparam_t));
  
  	cfg->ctxlen =
  		(!opts || !opts->context_lines) ? 3 : opts->context_lines;
  	cfg->interhunkctxlen =
  		(!opts) ? 0 : opts->interhunk_lines;
  
  	if (!opts)
  		return;
  
  	if (opts->flags & GIT_DIFF_IGNORE_WHITESPACE)
  		param->flags |= XDF_WHITESPACE_FLAGS;
  	if (opts->flags & GIT_DIFF_IGNORE_WHITESPACE_CHANGE)
  		param->flags |= XDF_IGNORE_WHITESPACE_CHANGE;
  	if (opts->flags & GIT_DIFF_IGNORE_WHITESPACE_EOL)
  		param->flags |= XDF_IGNORE_WHITESPACE_AT_EOL;
  }
  
  
  static int get_blob_content(
  	diff_context *ctxt,
  	git_diff_delta *delta,
  	git_diff_file *file,
  	git_map *map,
  	git_blob **blob)
  {
  	int error;
  	git_odb_object *odb_obj = NULL;
  
  	if (git_oid_iszero(&file->oid))
  		return 0;
  
  	if (file->mode == GIT_FILEMODE_COMMIT)
  	{
  		char oidstr[GIT_OID_HEXSZ+1];
  		git_buf content = GIT_BUF_INIT;
  
  		git_oid_fmt(oidstr, &file->oid);
  		oidstr[GIT_OID_HEXSZ] = 0;
  		git_buf_printf(&content, "Subproject commit %s\n", oidstr );
  
  		map->data = git_buf_detach(&content);
  		map->len = strlen(map->data);
  
  		file->flags |= GIT_DIFF_FILE_FREE_DATA;
  		return 0;
  	}
  
  	if (!file->size) {
  		git_odb *odb;
  		size_t len;
  		git_otype type;
  
  		/* peek at object header to avoid loading if too large */
  		if ((error = git_repository_odb__weakptr(&odb, ctxt->repo)) < 0 ||
  			(error = git_odb__read_header_or_object(
  				&odb_obj, &len, &type, odb, &file->oid)) < 0)
  			return error;
  
  		assert(type == GIT_OBJ_BLOB);
  
  		file->size = len;
  	}
  
  	/* if blob is too large to diff, mark as binary */
  	if ((error = diff_delta_is_binary_by_size(ctxt, delta, file)) < 0)
  		return error;
  	if (delta->binary == 1)
  		return 0;
  
  	if (odb_obj != NULL) {
  		error = git_object__from_odb_object(
  			(git_object **)blob, ctxt->repo, odb_obj, GIT_OBJ_BLOB);
  		git_odb_object_free(odb_obj);
  	} else
  		error = git_blob_lookup(blob, ctxt->repo, &file->oid);
  
  	if (error)
  		return error;
  
  	map->data = (void *)git_blob_rawcontent(*blob);
  	map->len  = (size_t)git_blob_rawsize(*blob);
  
  	return diff_delta_is_binary_by_content(ctxt, delta, file, map);
  }
  
  static int get_workdir_sm_content(
  	diff_context *ctxt,
  	git_diff_file *file,
  	git_map *map)
  {
  	int error = 0;
  	git_buf content = GIT_BUF_INIT;
  	git_submodule* sm = NULL;
  	unsigned int sm_status = 0;
  	const char* sm_status_text = "";
  	char oidstr[GIT_OID_HEXSZ+1];
  
  	if ((error = git_submodule_lookup(&sm, ctxt->repo, file->path)) < 0 ||
  		(error = git_submodule_status(&sm_status, sm)) < 0)
  		return error;
  
  	/* update OID if we didn't have it previously */
  	if ((file->flags & GIT_DIFF_FILE_VALID_OID) == 0) {
  		const git_oid* sm_head;
  
  		if ((sm_head = git_submodule_wd_id(sm)) != NULL ||
  			(sm_head = git_submodule_head_id(sm)) != NULL)
  		{
  			git_oid_cpy(&file->oid, sm_head);
  			file->flags |= GIT_DIFF_FILE_VALID_OID;
  		}
  	}
  
  	git_oid_fmt(oidstr, &file->oid);
  	oidstr[GIT_OID_HEXSZ] = '\0';
  
  	if (GIT_SUBMODULE_STATUS_IS_WD_DIRTY(sm_status))
  		sm_status_text = "-dirty";
  
  	git_buf_printf(&content, "Subproject commit %s%s\n",
  				   oidstr, sm_status_text);
  
  	map->data = git_buf_detach(&content);
  	map->len = strlen(map->data);
  
  	file->flags |= GIT_DIFF_FILE_FREE_DATA;
  
  	return 0;
  }
  
  static int get_workdir_content(
  	diff_context *ctxt,
  	git_diff_delta *delta,
  	git_diff_file *file,
  	git_map *map)
  {
  	int error = 0;
  	git_buf path = GIT_BUF_INIT;
  	const char *wd = git_repository_workdir(ctxt->repo);
  
  	if (S_ISGITLINK(file->mode))
  		return get_workdir_sm_content(ctxt, file, map);
  
  	if (S_ISDIR(file->mode))
  		return 0;
  
  	if (git_buf_joinpath(&path, wd, file->path) < 0)
  		return -1;
  
  	if (S_ISLNK(file->mode)) {
  		ssize_t alloc_len, read_len;
  
  		file->flags |= GIT_DIFF_FILE_FREE_DATA;
  		file->flags |= GIT_DIFF_FILE_BINARY;
  
  		/* link path on disk could be UTF-16, so prepare a buffer that is
  		 * big enough to handle some UTF-8 data expansion
  		 */
  		alloc_len = (ssize_t)(file->size * 2) + 1;
  
  		map->data = git__malloc(alloc_len);
  		GITERR_CHECK_ALLOC(map->data);
  
  		read_len = p_readlink(path.ptr, map->data, (int)alloc_len);
  		if (read_len < 0) {
  			giterr_set(GITERR_OS, "Failed to read symlink '%s'", file->path);
  			error = -1;
  			goto cleanup;
  		}
  
  		map->len = read_len;
  	}
  	else {
  		git_file fd = git_futils_open_ro(path.ptr);
  		git_vector filters = GIT_VECTOR_INIT;
  
  		if (fd < 0) {
  			error = fd;
  			goto cleanup;
  		}
  
  		if (!file->size)
  			file->size = git_futils_filesize(fd);
  
  		if ((error = diff_delta_is_binary_by_size(ctxt, delta, file)) < 0 ||
  			delta->binary == 1)
  			goto close_and_cleanup;
  
  		error = git_filters_load(
  			&filters, ctxt->repo, file->path, GIT_FILTER_TO_ODB);
  		if (error < 0)
  			goto close_and_cleanup;
  
  		if (error == 0) { /* note: git_filters_load returns filter count */
  			error = git_futils_mmap_ro(map, fd, 0, (size_t)file->size);
  			file->flags |= GIT_DIFF_FILE_UNMAP_DATA;
  		} else {
  			git_buf raw = GIT_BUF_INIT, filtered = GIT_BUF_INIT;
  
  			if (!(error = git_futils_readbuffer_fd(&raw, fd, (size_t)file->size)) &&
  				!(error = git_filters_apply(&filtered, &raw, &filters)))
  			{
  				map->len  = git_buf_len(&filtered);
  				map->data = git_buf_detach(&filtered);
  
  				file->flags |= GIT_DIFF_FILE_FREE_DATA;
  			}
  
  			git_buf_free(&raw);
  			git_buf_free(&filtered);
  		}
  
  close_and_cleanup:
  		git_filters_free(&filters);
  		p_close(fd);
  	}
  
  	/* once data is loaded, update OID if we didn't have it previously */
  	if (!error && (file->flags & GIT_DIFF_FILE_VALID_OID) == 0) {
  		error = git_odb_hash(
  			&file->oid, map->data, map->len, GIT_OBJ_BLOB);
  		if (!error)
  			file->flags |= GIT_DIFF_FILE_VALID_OID;
  	}
  
  	if (!error)
  		error = diff_delta_is_binary_by_content(ctxt, delta, file, map);
  
  cleanup:
  	git_buf_free(&path);
  	return error;
  }
  
  static void release_content(git_diff_file *file, git_map *map, git_blob *blob)
  {
  	if (blob != NULL)
  		git_blob_free(blob);
  
  	if (file->flags & GIT_DIFF_FILE_FREE_DATA) {
  		git__free(map->data);
  		map->data = "";
  		map->len  = 0;
  		file->flags &= ~GIT_DIFF_FILE_FREE_DATA;
  	}
  	else if (file->flags & GIT_DIFF_FILE_UNMAP_DATA) {
  		git_futils_mmap_free(map);
  		map->data = "";
  		map->len  = 0;
  		file->flags &= ~GIT_DIFF_FILE_UNMAP_DATA;
  	}
  }
  
  
  static void diff_context_init(
  	diff_context *ctxt,
  	git_diff_list *diff,
  	git_repository *repo,
  	const git_diff_options *opts,
  	git_diff_file_cb file_cb,
  	git_diff_hunk_cb hunk_cb,
  	git_diff_data_cb data_cb,
  	void *payload)
  {
  	memset(ctxt, 0, sizeof(diff_context));
  
  	ctxt->repo = repo;
  	ctxt->diff = diff;
  	ctxt->opts = opts;
  	ctxt->file_cb = file_cb;
  	ctxt->hunk_cb = hunk_cb;
  	ctxt->data_cb = data_cb;
  	ctxt->payload = payload;
  	ctxt->error = 0;
  
  	setup_xdiff_options(ctxt->opts, &ctxt->xdiff_config, &ctxt->xdiff_params);
  }
  
  static int diff_delta_file_callback(
  	diff_context *ctxt, git_diff_delta *delta, size_t idx)
  {
  	float progress;
  
  	if (!ctxt->file_cb)
  		return 0;
  
  	progress = ctxt->diff ? ((float)idx / ctxt->diff->deltas.length) : 1.0f;
  
  	if (ctxt->file_cb(delta, progress, ctxt->payload) != 0)
  		ctxt->error = GIT_EUSER;
  
  	return ctxt->error;
  }
  
  static void diff_patch_init(
  	diff_context *ctxt, git_diff_patch *patch)
  {
  	memset(patch, 0, sizeof(git_diff_patch));
  
  	patch->diff = ctxt->diff;
  	patch->ctxt = ctxt;
  
  	if (patch->diff) {
  		patch->old_src = patch->diff->old_src;
  		patch->new_src = patch->diff->new_src;
  	} else {
  		patch->old_src = patch->new_src = GIT_ITERATOR_TREE;
  	}
  }
  
  static git_diff_patch *diff_patch_alloc(
  	diff_context *ctxt, git_diff_delta *delta)
  {
  	git_diff_patch *patch = git__malloc(sizeof(git_diff_patch));
  	if (!patch)
  		return NULL;
  
  	diff_patch_init(ctxt, patch);
  
  	git_diff_list_addref(patch->diff);
  
  	GIT_REFCOUNT_INC(patch);
  
  	patch->delta = delta;
  	patch->flags = GIT_DIFF_PATCH_ALLOCATED;
  
  	return patch;
  }
  
  static int diff_patch_load(
  	diff_context *ctxt, git_diff_patch *patch)
  {
  	int error = 0;
  	git_diff_delta *delta = patch->delta;
  	bool check_if_unmodified = false;
  
  	if ((patch->flags & GIT_DIFF_PATCH_LOADED) != 0)
  		return 0;
  
  	error = diff_delta_is_binary_by_attr(ctxt, patch);
  
  	patch->old_data.data = "";
  	patch->old_data.len  = 0;
  	patch->old_blob      = NULL;
  
  	patch->new_data.data = "";
  	patch->new_data.len  = 0;
  	patch->new_blob      = NULL;
  
  	if (delta->binary == 1)
  		goto cleanup;
  
  	if (!ctxt->hunk_cb &&
  		!ctxt->data_cb &&
  		(ctxt->opts->flags & GIT_DIFF_SKIP_BINARY_CHECK) != 0)
  		goto cleanup;
  
  	switch (delta->status) {
  	case GIT_DELTA_ADDED:
  		delta->old_file.flags |= GIT_DIFF_FILE_NO_DATA;
  		break;
  	case GIT_DELTA_DELETED:
  		delta->new_file.flags |= GIT_DIFF_FILE_NO_DATA;
  		break;
  	case GIT_DELTA_MODIFIED:
  		break;
  	case GIT_DELTA_UNTRACKED:
  		delta->old_file.flags |= GIT_DIFF_FILE_NO_DATA;
  		if ((ctxt->opts->flags & GIT_DIFF_INCLUDE_UNTRACKED_CONTENT) == 0)
  			delta->new_file.flags |= GIT_DIFF_FILE_NO_DATA;
  		break;
  	default:
  		delta->new_file.flags |= GIT_DIFF_FILE_NO_DATA;
  		delta->old_file.flags |= GIT_DIFF_FILE_NO_DATA;
  		break;
  	}
  
  #define CHECK_UNMODIFIED (GIT_DIFF_FILE_NO_DATA | GIT_DIFF_FILE_VALID_OID)
  
  	check_if_unmodified =
  		(delta->old_file.flags & CHECK_UNMODIFIED) == 0 &&
  		(delta->new_file.flags & CHECK_UNMODIFIED) == 0;
  
  	/* Always try to load workdir content first, since it may need to be
  	 * filtered (and hence use 2x memory) and we want to minimize the max
  	 * memory footprint during diff.
  	 */
  
  	if ((delta->old_file.flags & GIT_DIFF_FILE_NO_DATA) == 0 &&
  		patch->old_src == GIT_ITERATOR_WORKDIR) {
  		if ((error = get_workdir_content(
  				ctxt, delta, &delta->old_file, &patch->old_data)) < 0)
  			goto cleanup;
  		if (delta->binary == 1)
  			goto cleanup;
  	}
  
  	if ((delta->new_file.flags & GIT_DIFF_FILE_NO_DATA) == 0 &&
  		patch->new_src == GIT_ITERATOR_WORKDIR) {
  		if ((error = get_workdir_content(
  				ctxt, delta, &delta->new_file, &patch->new_data)) < 0)
  			goto cleanup;
  		if (delta->binary == 1)
  			goto cleanup;
  	}
  
  	if ((delta->old_file.flags & GIT_DIFF_FILE_NO_DATA) == 0 &&
  		patch->old_src != GIT_ITERATOR_WORKDIR) {
  		if ((error = get_blob_content(
  				ctxt, delta, &delta->old_file,
  				&patch->old_data, &patch->old_blob)) < 0)
  			goto cleanup;
  		if (delta->binary == 1)
  			goto cleanup;
  	}
  
  	if ((delta->new_file.flags & GIT_DIFF_FILE_NO_DATA) == 0 &&
  		patch->new_src != GIT_ITERATOR_WORKDIR) {
  		if ((error = get_blob_content(
  				ctxt, delta, &delta->new_file,
  				&patch->new_data, &patch->new_blob)) < 0)
  			goto cleanup;
  		if (delta->binary == 1)
  			goto cleanup;
  	}
  
  	/* if we did not previously have the definitive oid, we may have
  	 * incorrect status and need to switch this to UNMODIFIED.
  	 */
  	if (check_if_unmodified &&
  		delta->old_file.mode == delta->new_file.mode &&
  		!git_oid_cmp(&delta->old_file.oid, &delta->new_file.oid))
  	{
  		delta->status = GIT_DELTA_UNMODIFIED;
  
  		if ((ctxt->opts->flags & GIT_DIFF_INCLUDE_UNMODIFIED) == 0)
  			goto cleanup;
  	}
  
  cleanup:
  	if (delta->binary == -1)
  		update_delta_is_binary(delta);
  
  	if (!error) {
  		patch->flags |= GIT_DIFF_PATCH_LOADED;
  
  		if (delta->binary != 1 &&
  			delta->status != GIT_DELTA_UNMODIFIED &&
  			(patch->old_data.len || patch->new_data.len) &&
  			!git_oid_equal(&delta->old_file.oid, &delta->new_file.oid))
  			patch->flags |= GIT_DIFF_PATCH_DIFFABLE;
  	}
  
  	return error;
  }
  
  static int diff_patch_cb(void *priv, mmbuffer_t *bufs, int len)
  {
  	git_diff_patch *patch = priv;
  	diff_context   *ctxt  = patch->ctxt;
  
  	if (len == 1) {
  		ctxt->error = parse_hunk_header(&ctxt->range, bufs[0].ptr);
  		if (ctxt->error < 0)
  			return ctxt->error;
  
  		if (ctxt->hunk_cb != NULL &&
  			ctxt->hunk_cb(patch->delta, &ctxt->range,
  				bufs[0].ptr, bufs[0].size, ctxt->payload))
  			ctxt->error = GIT_EUSER;
  	}
  
  	if (len == 2 || len == 3) {
  		/* expect " "/"-"/"+", then data */
  		char origin =
  			(*bufs[0].ptr == '+') ? GIT_DIFF_LINE_ADDITION :
  			(*bufs[0].ptr == '-') ? GIT_DIFF_LINE_DELETION :
  			GIT_DIFF_LINE_CONTEXT;
  
  		if (ctxt->data_cb != NULL &&
  			ctxt->data_cb(patch->delta, &ctxt->range,
  				origin, bufs[1].ptr, bufs[1].size, ctxt->payload))
  			ctxt->error = GIT_EUSER;
  	}
  
  	if (len == 3 && !ctxt->error) {
  		/* If we have a '+' and a third buf, then we have added a line
  		 * without a newline and the old code had one, so DEL_EOFNL.
  		 * If we have a '-' and a third buf, then we have removed a line
  		 * with out a newline but added a blank line, so ADD_EOFNL.
  		 */
  		char origin =
  			(*bufs[0].ptr == '+') ? GIT_DIFF_LINE_DEL_EOFNL :
  			(*bufs[0].ptr == '-') ? GIT_DIFF_LINE_ADD_EOFNL :
  			GIT_DIFF_LINE_CONTEXT;
  
  		if (ctxt->data_cb != NULL &&
  			ctxt->data_cb(patch->delta, &ctxt->range,
  				origin, bufs[2].ptr, bufs[2].size, ctxt->payload))
  			ctxt->error = GIT_EUSER;
  	}
  
  	return ctxt->error;
  }
  
  static int diff_patch_generate(
  	diff_context *ctxt, git_diff_patch *patch)
  {
  	int error = 0;
  	xdemitcb_t xdiff_callback;
  	mmfile_t old_xdiff_data, new_xdiff_data;
  
  	if ((patch->flags & GIT_DIFF_PATCH_DIFFED) != 0)
  		return 0;
  
  	if ((patch->flags & GIT_DIFF_PATCH_LOADED) == 0)
  		if ((error = diff_patch_load(ctxt, patch)) < 0)
  			return error;
  
  	if ((patch->flags & GIT_DIFF_PATCH_DIFFABLE) == 0)
  		return 0;
  
  	if (!ctxt->file_cb && !ctxt->hunk_cb)
  		return 0;
  
  	patch->ctxt = ctxt;
  
  	memset(&xdiff_callback, 0, sizeof(xdiff_callback));
  	xdiff_callback.outf = diff_patch_cb;
  	xdiff_callback.priv = patch;
  
  	old_xdiff_data.ptr  = patch->old_data.data;
  	old_xdiff_data.size = patch->old_data.len;
  	new_xdiff_data.ptr  = patch->new_data.data;
  	new_xdiff_data.size = patch->new_data.len;
  
  	xdl_diff(&old_xdiff_data, &new_xdiff_data,
  		&ctxt->xdiff_params, &ctxt->xdiff_config, &xdiff_callback);
  
  	error = ctxt->error;
  
  	if (!error)
  		patch->flags |= GIT_DIFF_PATCH_DIFFED;
  
  	return error;
  }
  
  static void diff_patch_unload(git_diff_patch *patch)
  {
  	if ((patch->flags & GIT_DIFF_PATCH_DIFFED) != 0) {
  		patch->flags = (patch->flags & ~GIT_DIFF_PATCH_DIFFED);
  
  		patch->hunks_size = 0;
  		patch->lines_size = 0;
  	}
  
  	if ((patch->flags & GIT_DIFF_PATCH_LOADED) != 0) {
  		patch->flags = (patch->flags & ~GIT_DIFF_PATCH_LOADED);
  
  		release_content(
  			&patch->delta->old_file, &patch->old_data, patch->old_blob);
  		release_content(
  			&patch->delta->new_file, &patch->new_data, patch->new_blob);
  	}
  }
  
  static void diff_patch_free(git_diff_patch *patch)
  {
  	diff_patch_unload(patch);
  
  	git__free(patch->lines);
  	patch->lines = NULL;
  	patch->lines_asize = 0;
  
  	git__free(patch->hunks);
  	patch->hunks = NULL;
  	patch->hunks_asize = 0;
  
  	if (!(patch->flags & GIT_DIFF_PATCH_ALLOCATED))
  		return;
  
  	patch->flags = 0;
  
  	git_diff_list_free(patch->diff); /* decrements refcount */
  
  	git__free(patch);
  }
  
  #define MAX_HUNK_STEP 128
  #define MIN_HUNK_STEP 8
  #define MAX_LINE_STEP 256
  #define MIN_LINE_STEP 8
  
  static int diff_patch_hunk_cb(
  	const git_diff_delta *delta,
  	const git_diff_range *range,
  	const char *header,
  	size_t header_len,
  	void *payload)
  {
  	git_diff_patch *patch = payload;
  	diff_patch_hunk *hunk;
  
  	GIT_UNUSED(delta);
  
  	if (patch->hunks_size >= patch->hunks_asize) {
  		size_t new_size;
  		diff_patch_hunk *new_hunks;
  
  		if (patch->hunks_asize > MAX_HUNK_STEP)
  			new_size = patch->hunks_asize + MAX_HUNK_STEP;
  		else
  			new_size = patch->hunks_asize * 2;
  		if (new_size < MIN_HUNK_STEP)
  			new_size = MIN_HUNK_STEP;
  
  		new_hunks = git__realloc(
  			patch->hunks, new_size * sizeof(diff_patch_hunk));
  		if (!new_hunks)
  			return -1;
  
  		patch->hunks = new_hunks;
  		patch->hunks_asize = new_size;
  	}
  
  	hunk = &patch->hunks[patch->hunks_size++];
  
  	memcpy(&hunk->range, range, sizeof(hunk->range));
  
  	assert(header_len + 1 < sizeof(hunk->header));
  	memcpy(&hunk->header, header, header_len);
  	hunk->header[header_len] = '\0';
  	hunk->header_len = header_len;
  
  	hunk->line_start = patch->lines_size;
  	hunk->line_count = 0;
  
  	return 0;
  }
  
  static int diff_patch_line_cb(
  	const git_diff_delta *delta,
  	const git_diff_range *range,
  	char line_origin,
  	const char *content,
  	size_t content_len,
  	void *payload)
  {
  	git_diff_patch *patch = payload;
  	diff_patch_hunk *hunk;
  	diff_patch_line *last, *line;
  
  	GIT_UNUSED(delta);
  	GIT_UNUSED(range);
  
  	assert(patch->hunks_size > 0);
  	assert(patch->hunks != NULL);
  
  	hunk = &patch->hunks[patch->hunks_size - 1];
  
  	if (patch->lines_size >= patch->lines_asize) {
  		size_t new_size;
  		diff_patch_line *new_lines;
  
  		if (patch->lines_asize > MAX_LINE_STEP)
  			new_size = patch->lines_asize + MAX_LINE_STEP;
  		else
  			new_size = patch->lines_asize * 2;
  		if (new_size < MIN_LINE_STEP)
  			new_size = MIN_LINE_STEP;
  
  		new_lines = git__realloc(
  			patch->lines, new_size * sizeof(diff_patch_line));
  		if (!new_lines)
  			return -1;
  
  		patch->lines = new_lines;
  		patch->lines_asize = new_size;
  	}
  
  	last = (patch->lines_size > 0) ?
  		&patch->lines[patch->lines_size - 1] : NULL;
  	line = &patch->lines[patch->lines_size++];
  
  	line->ptr = content;
  	line->len = content_len;
  	line->origin = line_origin;
  
  	/* do some bookkeeping so we can provide old/new line numbers */
  
  	for (line->lines = 0; content_len > 0; --content_len) {
  		if (*content++ == '\n')
  			++line->lines;
  	}
  
  	if (!last) {
  		line->oldno = hunk->range.old_start;
  		line->newno = hunk->range.new_start;
  	} else {
  		switch (last->origin) {
  		case GIT_DIFF_LINE_ADDITION:
  			line->oldno = last->oldno;
  			line->newno = last->newno + last->lines;
  			break;
  		case GIT_DIFF_LINE_DELETION:
  			line->oldno = last->oldno + last->lines;
  			line->newno = last->newno;
  			break;
  		default:
  			line->oldno = last->oldno + last->lines;
  			line->newno = last->newno + last->lines;
  			break;
  		}
  	}
  
  	hunk->line_count++;
  
  	return 0;
  }
  
  
  int git_diff_foreach(
  	git_diff_list *diff,
  	git_diff_file_cb file_cb,
  	git_diff_hunk_cb hunk_cb,
  	git_diff_data_cb data_cb,
  	void *payload)
  {
  	int error = 0;
  	diff_context ctxt;
  	size_t idx;
  	git_diff_patch patch;
  
  	diff_context_init(
  		&ctxt, diff, diff->repo, &diff->opts,
  		file_cb, hunk_cb, data_cb, payload);
  
  	diff_patch_init(&ctxt, &patch);
  
  	git_vector_foreach(&diff->deltas, idx, patch.delta) {
  
  		/* check flags against patch status */
  		if (git_diff_delta__should_skip(ctxt.opts, patch.delta))
  			continue;
  
  		if (!(error = diff_patch_load(&ctxt, &patch))) {
  
  			/* invoke file callback */
  			error = diff_delta_file_callback(&ctxt, patch.delta, idx);
  
  			/* generate diffs and invoke hunk and line callbacks */
  			if (!error)
  				error = diff_patch_generate(&ctxt, &patch);
  
  			diff_patch_unload(&patch);
  		}
  
  		if (error < 0)
  			break;
  	}
  
  	if (error == GIT_EUSER)
  		giterr_clear(); /* don't let error message leak */
  
  	return error;
  }
  
  
  typedef struct {
  	git_diff_list *diff;
  	git_diff_data_cb print_cb;
  	void *payload;
  	git_buf *buf;
  } diff_print_info;
  
  static char pick_suffix(int mode)
  {
  	if (S_ISDIR(mode))
  		return '/';
  	else if (mode & 0100) //-V536
  		/* in git, modes are very regular, so we must have 0100755 mode */
  		return '*';
  	else
  		return ' ';
  }
  
  char git_diff_status_char(git_delta_t status)
  {
  	char code;
  
  	switch (status) {
  	case GIT_DELTA_ADDED:     code = 'A'; break;
  	case GIT_DELTA_DELETED:   code = 'D'; break;
  	case GIT_DELTA_MODIFIED:  code = 'M'; break;
  	case GIT_DELTA_RENAMED:   code = 'R'; break;
  	case GIT_DELTA_COPIED:    code = 'C'; break;
  	case GIT_DELTA_IGNORED:   code = 'I'; break;
  	case GIT_DELTA_UNTRACKED: code = '?'; break;
  	default:                  code = ' '; break;
  	}
  
  	return code;
  }
  
  static int print_compact(
  	const git_diff_delta *delta, float progress, void *data)
  {
  	diff_print_info *pi = data;
  	char old_suffix, new_suffix, code = git_diff_status_char(delta->status);
  
  	GIT_UNUSED(progress);
  
  	if (code == ' ')
  		return 0;
  
  	old_suffix = pick_suffix(delta->old_file.mode);
  	new_suffix = pick_suffix(delta->new_file.mode);
  
  	git_buf_clear(pi->buf);
  
  	if (delta->old_file.path != delta->new_file.path &&
  		pi->diff->strcomp(delta->old_file.path,delta->new_file.path) != 0)
  		git_buf_printf(pi->buf, "%c\t%s%c -> %s%c\n", code,
  			delta->old_file.path, old_suffix, delta->new_file.path, new_suffix);
  	else if (delta->old_file.mode != delta->new_file.mode &&
  		delta->old_file.mode != 0 && delta->new_file.mode != 0)
  		git_buf_printf(pi->buf, "%c\t%s%c (%o -> %o)\n", code,
  			delta->old_file.path, new_suffix, delta->old_file.mode, delta->new_file.mode);
  	else if (old_suffix != ' ')
  		git_buf_printf(pi->buf, "%c\t%s%c\n", code, delta->old_file.path, old_suffix);
  	else
  		git_buf_printf(pi->buf, "%c\t%s\n", code, delta->old_file.path);
  
  	if (git_buf_oom(pi->buf))
  		return -1;
  
  	if (pi->print_cb(delta, NULL, GIT_DIFF_LINE_FILE_HDR,
  			git_buf_cstr(pi->buf), git_buf_len(pi->buf), pi->payload))
  	{
  		giterr_clear();
  		return GIT_EUSER;
  	}
  
  	return 0;
  }
  
  int git_diff_print_compact(
  	git_diff_list *diff,
  	git_diff_data_cb print_cb,
  	void *payload)
  {
  	int error;
  	git_buf buf = GIT_BUF_INIT;
  	diff_print_info pi;
  
  	pi.diff     = diff;
  	pi.print_cb = print_cb;
  	pi.payload  = payload;
  	pi.buf      = &buf;
  
  	error = git_diff_foreach(diff, print_compact, NULL, NULL, &pi);
  
  	git_buf_free(&buf);
  
  	return error;
  }
  
  static int print_oid_range(diff_print_info *pi, const git_diff_delta *delta)
  {
  	char start_oid[8], end_oid[8];
  
  	/* TODO: Determine a good actual OID range to print */
  	git_oid_tostr(start_oid, sizeof(start_oid), &delta->old_file.oid);
  	git_oid_tostr(end_oid, sizeof(end_oid), &delta->new_file.oid);
  
  	/* TODO: Match git diff more closely */
  	if (delta->old_file.mode == delta->new_file.mode) {
  		git_buf_printf(pi->buf, "index %s..%s %o\n",
  			start_oid, end_oid, delta->old_file.mode);
  	} else {
  		if (delta->old_file.mode == 0) {
  			git_buf_printf(pi->buf, "new file mode %o\n", delta->new_file.mode);
  		} else if (delta->new_file.mode == 0) {
  			git_buf_printf(pi->buf, "deleted file mode %o\n", delta->old_file.mode);
  		} else {
  			git_buf_printf(pi->buf, "old mode %o\n", delta->old_file.mode);
  			git_buf_printf(pi->buf, "new mode %o\n", delta->new_file.mode);
  		}
  		git_buf_printf(pi->buf, "index %s..%s\n", start_oid, end_oid);
  	}
  
  	if (git_buf_oom(pi->buf))
  		return -1;
  
  	return 0;
  }
  
  static int print_patch_file(
  	const git_diff_delta *delta, float progress, void *data)
  {
  	diff_print_info *pi = data;
  	const char *oldpfx = pi->diff->opts.old_prefix;
  	const char *oldpath = delta->old_file.path;
  	const char *newpfx = pi->diff->opts.new_prefix;
  	const char *newpath = delta->new_file.path;
  
  	GIT_UNUSED(progress);
  
  	if (S_ISDIR(delta->new_file.mode))
  		return 0;
  
  	if (!oldpfx)
  		oldpfx = DIFF_OLD_PREFIX_DEFAULT;
  
  	if (!newpfx)
  		newpfx = DIFF_NEW_PREFIX_DEFAULT;
  
  	git_buf_clear(pi->buf);
  	git_buf_printf(pi->buf, "diff --git %s%s %s%s\n", oldpfx, delta->old_file.path, newpfx, delta->new_file.path);
  
  	if (print_oid_range(pi, delta) < 0)
  		return -1;
  
  	if (git_oid_iszero(&delta->old_file.oid)) {
  		oldpfx = "";
  		oldpath = "/dev/null";
  	}
  	if (git_oid_iszero(&delta->new_file.oid)) {
  		newpfx = "";
  		newpath = "/dev/null";
  	}
  
  	if (delta->binary != 1) {
  		git_buf_printf(pi->buf, "--- %s%s\n", oldpfx, oldpath);
  		git_buf_printf(pi->buf, "+++ %s%s\n", newpfx, newpath);
  	}
  
  	if (git_buf_oom(pi->buf))
  		return -1;
  
  	if (pi->print_cb(delta, NULL, GIT_DIFF_LINE_FILE_HDR,
  			git_buf_cstr(pi->buf), git_buf_len(pi->buf), pi->payload))
  	{
  		giterr_clear();
  		return GIT_EUSER;
  	}
  
  	if (delta->binary != 1)
  		return 0;
  
  	git_buf_clear(pi->buf);
  	git_buf_printf(
  		pi->buf, "Binary files %s%s and %s%s differ\n",
  		oldpfx, oldpath, newpfx, newpath);
  	if (git_buf_oom(pi->buf))
  		return -1;
  
  	if (pi->print_cb(delta, NULL, GIT_DIFF_LINE_BINARY,
  			git_buf_cstr(pi->buf), git_buf_len(pi->buf), pi->payload))
  	{
  		giterr_clear();
  		return GIT_EUSER;
  	}
  
  	return 0;
  }
  
  static int print_patch_hunk(
  	const git_diff_delta *d,
  	const git_diff_range *r,
  	const char *header,
  	size_t header_len,
  	void *data)
  {
  	diff_print_info *pi = data;
  
  	if (S_ISDIR(d->new_file.mode))
  		return 0;
  
  	git_buf_clear(pi->buf);
  	if (git_buf_printf(pi->buf, "%.*s", (int)header_len, header) < 0)
  		return -1;
  
  	if (pi->print_cb(d, r, GIT_DIFF_LINE_HUNK_HDR,
  			git_buf_cstr(pi->buf), git_buf_len(pi->buf), pi->payload))
  	{
  		giterr_clear();
  		return GIT_EUSER;
  	}
  
  	return 0;
  }
  
  static int print_patch_line(
  	const git_diff_delta *delta,
  	const git_diff_range *range,
  	char line_origin, /* GIT_DIFF_LINE value from above */
  	const char *content,
  	size_t content_len,
  	void *data)
  {
  	diff_print_info *pi = data;
  
  	if (S_ISDIR(delta->new_file.mode))
  		return 0;
  
  	git_buf_clear(pi->buf);
  
  	if (line_origin == GIT_DIFF_LINE_ADDITION ||
  		line_origin == GIT_DIFF_LINE_DELETION ||
  		line_origin == GIT_DIFF_LINE_CONTEXT)
  		git_buf_printf(pi->buf, "%c%.*s", line_origin, (int)content_len, content);
  	else if (content_len > 0)
  		git_buf_printf(pi->buf, "%.*s", (int)content_len, content);
  
  	if (git_buf_oom(pi->buf))
  		return -1;
  
  	if (pi->print_cb(delta, range, line_origin,
  			git_buf_cstr(pi->buf), git_buf_len(pi->buf), pi->payload))
  	{
  		giterr_clear();
  		return GIT_EUSER;
  	}
  
  	return 0;
  }
  
  int git_diff_print_patch(
  	git_diff_list *diff,
  	git_diff_data_cb print_cb,
  	void *payload)
  {
  	int error;
  	git_buf buf = GIT_BUF_INIT;
  	diff_print_info pi;
  
  	pi.diff     = diff;
  	pi.print_cb = print_cb;
  	pi.payload  = payload;
  	pi.buf      = &buf;
  
  	error = git_diff_foreach(
  		diff, print_patch_file, print_patch_hunk, print_patch_line, &pi);
  
  	git_buf_free(&buf);
  
  	return error;
  }
  
  
  static void set_data_from_blob(
  	git_blob *blob, git_map *map, git_diff_file *file)
  {
  	if (blob) {
  		file->size = git_blob_rawsize(blob);
  		git_oid_cpy(&file->oid, git_object_id((const git_object *)blob));
  		file->mode = 0644;
  
  		map->len   = (size_t)file->size;
  		map->data  = (char *)git_blob_rawcontent(blob);
  	} else {
  		file->size = 0;
  		file->flags |= GIT_DIFF_FILE_NO_DATA;
  
  		map->len   = 0;
  		map->data  = "";
  	}
  }
  
  int git_diff_blobs(
  	git_blob *old_blob,
  	git_blob *new_blob,
  	const git_diff_options *options,
  	git_diff_file_cb file_cb,
  	git_diff_hunk_cb hunk_cb,
  	git_diff_data_cb data_cb,
  	void *payload)
  {
  	int error;
  	git_repository *repo;
  	diff_context ctxt;
  	git_diff_delta delta;
  	git_diff_patch patch;
  
  	if (options && (options->flags & GIT_DIFF_REVERSE)) {
  		git_blob *swap = old_blob;
  		old_blob = new_blob;
  		new_blob = swap;
  	}
  
  	if (new_blob)
  		repo = git_object_owner((git_object *)new_blob);
  	else if (old_blob)
  		repo = git_object_owner((git_object *)old_blob);
  	else
  		repo = NULL;
  
  	diff_context_init(
  		&ctxt, NULL, repo, options,
  		file_cb, hunk_cb, data_cb, payload);
  
  	diff_patch_init(&ctxt, &patch);
  
  	/* create a fake delta record and simulate diff_patch_load */
  
  	memset(&delta, 0, sizeof(delta));
  	delta.binary = -1;
  
  	set_data_from_blob(old_blob, &patch.old_data, &delta.old_file);
  	set_data_from_blob(new_blob, &patch.new_data, &delta.new_file);
  
  	delta.status = new_blob ?
  		(old_blob ? GIT_DELTA_MODIFIED : GIT_DELTA_ADDED) :
  		(old_blob ? GIT_DELTA_DELETED : GIT_DELTA_UNTRACKED);
  
  	if (git_oid_cmp(&delta.new_file.oid, &delta.old_file.oid) == 0)
  		delta.status = GIT_DELTA_UNMODIFIED;
  
  	patch.delta = &delta;
  
  	if ((error = diff_delta_is_binary_by_content(
  			 &ctxt, &delta, &delta.old_file, &patch.old_data)) < 0 ||
  		(error = diff_delta_is_binary_by_content(
  			&ctxt, &delta, &delta.new_file, &patch.new_data)) < 0)
  		goto cleanup;
  
  	patch.flags |= GIT_DIFF_PATCH_LOADED;
  	if (delta.binary != 1 && delta.status != GIT_DELTA_UNMODIFIED)
  		patch.flags |= GIT_DIFF_PATCH_DIFFABLE;
  
  	/* do diffs */
  
  	if (!(error = diff_delta_file_callback(&ctxt, patch.delta, 1)))
  		error = diff_patch_generate(&ctxt, &patch);
  
  cleanup:
  	diff_patch_unload(&patch);
  
  	if (error == GIT_EUSER)
  		giterr_clear();
  
  	return error;
  }
  
  
  size_t git_diff_num_deltas(git_diff_list *diff)
  {
  	assert(diff);
  	return (size_t)diff->deltas.length;
  }
  
  size_t git_diff_num_deltas_of_type(git_diff_list *diff, git_delta_t type)
  {
  	size_t i, count = 0;
  	git_diff_delta *delta;
  
  	assert(diff);
  
  	git_vector_foreach(&diff->deltas, i, delta) {
  		count += (delta->status == type);
  	}
  
  	return count;
  }
  
  int git_diff_get_patch(
  	git_diff_patch **patch_ptr,
  	const git_diff_delta **delta_ptr,
  	git_diff_list *diff,
  	size_t idx)
  {
  	int error;
  	diff_context ctxt;
  	git_diff_delta *delta;
  	git_diff_patch *patch;
  
  	if (patch_ptr)
  		*patch_ptr = NULL;
  
  	delta = git_vector_get(&diff->deltas, idx);
  	if (!delta) {
  		if (delta_ptr)
  			*delta_ptr = NULL;
  		giterr_set(GITERR_INVALID, "Index out of range for delta in diff");
  		return GIT_ENOTFOUND;
  	}
  
  	if (delta_ptr)
  		*delta_ptr = delta;
  
  	if (!patch_ptr &&
  		(delta->binary != -1 ||
  		 (diff->opts.flags & GIT_DIFF_SKIP_BINARY_CHECK) != 0))
  		return 0;
  
  	diff_context_init(
  		&ctxt, diff, diff->repo, &diff->opts,
  		NULL, diff_patch_hunk_cb, diff_patch_line_cb, NULL);
  
  	if (git_diff_delta__should_skip(ctxt.opts, delta))
  		return 0;
  
  	patch = diff_patch_alloc(&ctxt, delta);
  	if (!patch)
  		return -1;
  
  	if (!(error = diff_patch_load(&ctxt, patch))) {
  		ctxt.payload = patch;
  
  		error = diff_patch_generate(&ctxt, patch);
  
  		if (error == GIT_EUSER)
  			error = ctxt.error;
  	}
  
  	if (error)
  		git_diff_patch_free(patch);
  	else if (patch_ptr)
  		*patch_ptr = patch;
  
  	return error;
  }
  
  void git_diff_patch_free(git_diff_patch *patch)
  {
  	if (patch)
  		GIT_REFCOUNT_DEC(patch, diff_patch_free);
  }
  
  const git_diff_delta *git_diff_patch_delta(git_diff_patch *patch)
  {
  	assert(patch);
  	return patch->delta;
  }
  
  size_t git_diff_patch_num_hunks(git_diff_patch *patch)
  {
  	assert(patch);
  	return patch->hunks_size;
  }
  
  int git_diff_patch_get_hunk(
  	const git_diff_range **range,
  	const char **header,
  	size_t *header_len,
  	size_t *lines_in_hunk,
  	git_diff_patch *patch,
  	size_t hunk_idx)
  {
  	diff_patch_hunk *hunk;
  
  	assert(patch);
  
  	if (hunk_idx >= patch->hunks_size) {
  		if (range) *range = NULL;
  		if (header) *header = NULL;
  		if (header_len) *header_len = 0;
  		if (lines_in_hunk) *lines_in_hunk = 0;
  		return GIT_ENOTFOUND;
  	}
  
  	hunk = &patch->hunks[hunk_idx];
  
  	if (range) *range = &hunk->range;
  	if (header) *header = hunk->header;
  	if (header_len) *header_len = hunk->header_len;
  	if (lines_in_hunk) *lines_in_hunk = hunk->line_count;
  
  	return 0;
  }
  
  int git_diff_patch_num_lines_in_hunk(
  	git_diff_patch *patch,
  	size_t hunk_idx)
  {
  	assert(patch);
  
  	if (hunk_idx >= patch->hunks_size)
  		return GIT_ENOTFOUND;
  	else
  		return (int)patch->hunks[hunk_idx].line_count;
  }
  
  int git_diff_patch_get_line_in_hunk(
  	char *line_origin,
  	const char **content,
  	size_t *content_len,
  	int *old_lineno,
  	int *new_lineno,
  	git_diff_patch *patch,
  	size_t hunk_idx,
  	size_t line_of_hunk)
  {
  	diff_patch_hunk *hunk;
  	diff_patch_line *line;
  
  	assert(patch);
  
  	if (hunk_idx >= patch->hunks_size)
  		goto notfound;
  	hunk = &patch->hunks[hunk_idx];
  
  	if (line_of_hunk >= hunk->line_count)
  		goto notfound;
  
  	line = &patch->lines[hunk->line_start + line_of_hunk];
  
  	if (line_origin) *line_origin = line->origin;
  	if (content) *content = line->ptr;
  	if (content_len) *content_len = line->len;
  	if (old_lineno) *old_lineno = line->oldno;
  	if (new_lineno) *new_lineno = line->newno;
  
  	return 0;
  
  notfound:
  	if (line_origin) *line_origin = GIT_DIFF_LINE_CONTEXT;
  	if (content) *content = NULL;
  	if (content_len) *content_len = 0;
  	if (old_lineno) *old_lineno = -1;
  	if (new_lineno) *new_lineno = -1;
  
  	return GIT_ENOTFOUND;
  }
  
  static int print_to_buffer_cb(
      const git_diff_delta *delta,
      const git_diff_range *range,
      char line_origin,
      const char *content,
      size_t content_len,
      void *payload)
  {
  	git_buf *output = payload;
  	GIT_UNUSED(delta); GIT_UNUSED(range); GIT_UNUSED(line_origin);
  	return git_buf_put(output, content, content_len);
  }
  
  int git_diff_patch_print(
  	git_diff_patch *patch,
  	git_diff_data_cb print_cb,
  	void *payload)
  {
  	int error;
  	git_buf temp = GIT_BUF_INIT;
  	diff_print_info pi;
  	size_t h, l;
  
  	assert(patch && print_cb);
  
  	pi.diff     = patch->diff;
  	pi.print_cb = print_cb;
  	pi.payload  = payload;
  	pi.buf      = &temp;
  
  	error = print_patch_file(patch->delta, 0, &pi);
  
  	for (h = 0; h < patch->hunks_size && !error; ++h) {
  		diff_patch_hunk *hunk = &patch->hunks[h];
  
  		error = print_patch_hunk(
  			patch->delta, &hunk->range, hunk->header, hunk->header_len, &pi);
  
  		for (l = 0; l < hunk->line_count && !error; ++l) {
  			diff_patch_line *line = &patch->lines[hunk->line_start + l];
  
  			error = print_patch_line(
  				patch->delta, &hunk->range,
  				line->origin, line->ptr, line->len, &pi);
  		}
  	}
  
  	git_buf_free(&temp);
  
  	return error;
  }
  
  int git_diff_patch_to_str(
  	char **string,
  	git_diff_patch *patch)
  {
  	int error;
  	git_buf output = GIT_BUF_INIT;
  
  	error = git_diff_patch_print(patch, print_to_buffer_cb, &output);
  
  	/* GIT_EUSER means git_buf_put in print_to_buffer_cb returned -1,
  	 * meaning a memory allocation failure, so just map to -1...
  	 */
  	if (error == GIT_EUSER)
  		error = -1;
  
  	*string = git_buf_detach(&output);
  
  	return error;
  }
  
  int git_diff__paired_foreach(
  	git_diff_list *idx2head,
  	git_diff_list *wd2idx,
  	int (*cb)(git_diff_delta *i2h, git_diff_delta *w2i, void *payload),
  	void *payload)
  {
  	int cmp;
  	git_diff_delta *i2h, *w2i;
  	size_t i, j, i_max, j_max;
  	bool icase = false;
  
  	i_max = idx2head ? idx2head->deltas.length : 0;
  	j_max = wd2idx   ? wd2idx->deltas.length   : 0;
  
  	if (idx2head && wd2idx &&
  		(0 != (idx2head->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE) ||
  		 0 != (wd2idx->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE)))
  	{
  		/* Then use the ignore-case sorter... */
  		icase = true;
  
  		/* and assert that both are ignore-case sorted. If this function
  		 * ever needs to support merge joining result sets that are not sorted
  		 * by the same function, then it will need to be extended to do a spool
  		 * and sort on one of the results before merge joining */
  		assert(0 != (idx2head->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE) &&
  			0 != (wd2idx->opts.flags & GIT_DIFF_DELTAS_ARE_ICASE));
  	}
  
  	for (i = 0, j = 0; i < i_max || j < j_max; ) {
  		i2h = idx2head ? GIT_VECTOR_GET(&idx2head->deltas,i) : NULL;
  		w2i = wd2idx   ? GIT_VECTOR_GET(&wd2idx->deltas,j)   : NULL;
  
  		cmp = !w2i ? -1 : !i2h ? 1 :
  			STRCMP_CASESELECT(icase, i2h->old_file.path, w2i->old_file.path);
  
  		if (cmp < 0) {
  			if (cb(i2h, NULL, payload))
  				return GIT_EUSER;
  			i++;
  		} else if (cmp > 0) {
  			if (cb(NULL, w2i, payload))
  				return GIT_EUSER;
  			j++;
  		} else {
  			if (cb(i2h, w2i, payload))
  				return GIT_EUSER;
  			i++; j++;
  		}
  	}
  
  	return 0;
  }
  
  

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