builtin/cat-file.c - jrn/git - Git at Google

 /*
  * GIT - The information manager from hell
  *
  * Copyright (C) Linus Torvalds, 2005
  */
 #include "cache.h"
 #include "builtin.h"
 #include "parse-options.h"
 #include "userdiff.h"
 #include "streaming.h"
 #include "tree-walk.h"
 #include "sha1-array.h"

 struct batch_options {
 	int enabled;
 	int follow_symlinks;
 	int print_contents;
 	int buffer_output;
 	int all_objects;
 	const char *format;
 };

 static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
 			int unknown_type)
 {
 	unsigned char sha1[20];
 	enum object_type type;
 	char *buf;
 	unsigned long size;
 	struct object_context obj_context;
 	struct object_info oi = {NULL};
 	struct strbuf sb = STRBUF_INIT;
 	unsigned flags = LOOKUP_REPLACE_OBJECT;

 	if (unknown_type)
 		flags |= LOOKUP_UNKNOWN_OBJECT;

 	if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
 		die("Not a valid object name %s", obj_name);

 	buf = NULL;
 	switch (opt) {
 	case 't':
 		oi.typename = &sb;
 		if (sha1_object_info_extended(sha1, &oi, flags) < 0)
 			die("git cat-file: could not get object info");
 		if (sb.len) {
 			printf("%s\n", sb.buf);
 			strbuf_release(&sb);
 			return 0;
 		}
 		break;

 	case 's':
 		oi.sizep = &size;
 		if (sha1_object_info_extended(sha1, &oi, flags) < 0)
 			die("git cat-file: could not get object info");
 		printf("%lu\n", size);
 		return 0;

 	case 'e':
 		return !has_sha1_file(sha1);

 	case 'c':
 		if (!obj_context.path[0])
 			die("git cat-file --textconv %s: <object> must be <sha1:path>",
 			    obj_name);

 		if (textconv_object(obj_context.path, obj_context.mode, sha1, 1, &buf, &size))
 			break;

 	case 'p':
 		type = sha1_object_info(sha1, NULL);
 		if (type < 0)
 			die("Not a valid object name %s", obj_name);

 		/* custom pretty-print here */
 		if (type == OBJ_TREE) {
 			const char *ls_args[3] = { NULL };
 			ls_args[0] =  "ls-tree";
 			ls_args[1] =  obj_name;
 			return cmd_ls_tree(2, ls_args, NULL);
 		}

 		if (type == OBJ_BLOB)
 			return stream_blob_to_fd(1, sha1, NULL, 0);
 		buf = read_sha1_file(sha1, &type, &size);
 		if (!buf)
 			die("Cannot read object %s", obj_name);

 		/* otherwise just spit out the data */
 		break;

 	case 0:
 		if (type_from_string(exp_type) == OBJ_BLOB) {
 			unsigned char blob_sha1[20];
 			if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
 				char *buffer = read_sha1_file(sha1, &type, &size);
 				const char *target;
 				if (!skip_prefix(buffer, "object ", &target) ||
 				    get_sha1_hex(target, blob_sha1))
 					die("%s not a valid tag", sha1_to_hex(sha1));
 				free(buffer);
 			} else
 				hashcpy(blob_sha1, sha1);

 			if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
 				return stream_blob_to_fd(1, blob_sha1, NULL, 0);
 			/*
 			 * we attempted to dereference a tag to a blob
 			 * and failed; there may be new dereference
 			 * mechanisms this code is not aware of.
 			 * fall-back to the usual case.
 			 */
 		}
 		buf = read_object_with_reference(sha1, exp_type, &size, NULL);
 		break;

 	default:
 		die("git cat-file: unknown option: %s", exp_type);
 	}

 	if (!buf)
 		die("git cat-file %s: bad file", obj_name);

 	write_or_die(1, buf, size);
 	return 0;
 }

 struct expand_data {
 	unsigned char sha1[20];
 	enum object_type type;
 	unsigned long size;
 	unsigned long disk_size;
 	const char *rest;
 	unsigned char delta_base_sha1[20];

 	/*
 	 * If mark_query is true, we do not expand anything, but rather
 	 * just mark the object_info with items we wish to query.
 	 */
 	int mark_query;

 	/*
 	 * Whether to split the input on whitespace before feeding it to
 	 * get_sha1; this is decided during the mark_query phase based on
 	 * whether we have a %(rest) token in our format.
 	 */
 	int split_on_whitespace;

 	/*
 	 * After a mark_query run, this object_info is set up to be
 	 * passed to sha1_object_info_extended. It will point to the data
 	 * elements above, so you can retrieve the response from there.
 	 */
 	struct object_info info;

 	/*
 	 * This flag will be true if the requested batch format and options
 	 * don't require us to call sha1_object_info, which can then be
 	 * optimized out.
 	 */
 	unsigned skip_object_info : 1;
 };

 static int is_atom(const char *atom, const char *s, int slen)
 {
 	int alen = strlen(atom);
 	return alen == slen && !memcmp(atom, s, alen);
 }

 static void expand_atom(struct strbuf *sb, const char *atom, int len,
 			void *vdata)
 {
 	struct expand_data *data = vdata;

 	if (is_atom("objectname", atom, len)) {
 		if (!data->mark_query)
 			strbuf_addstr(sb, sha1_to_hex(data->sha1));
 	} else if (is_atom("objecttype", atom, len)) {
 		if (data->mark_query)
 			data->info.typep = &data->type;
 		else
 			strbuf_addstr(sb, typename(data->type));
 	} else if (is_atom("objectsize", atom, len)) {
 		if (data->mark_query)
 			data->info.sizep = &data->size;
 		else
 			strbuf_addf(sb, "%lu", data->size);
 	} else if (is_atom("objectsize:disk", atom, len)) {
 		if (data->mark_query)
 			data->info.disk_sizep = &data->disk_size;
 		else
 			strbuf_addf(sb, "%lu", data->disk_size);
 	} else if (is_atom("rest", atom, len)) {
 		if (data->mark_query)
 			data->split_on_whitespace = 1;
 		else if (data->rest)
 			strbuf_addstr(sb, data->rest);
 	} else if (is_atom("deltabase", atom, len)) {
 		if (data->mark_query)
 			data->info.delta_base_sha1 = data->delta_base_sha1;
 		else
 			strbuf_addstr(sb, sha1_to_hex(data->delta_base_sha1));
 	} else
 		die("unknown format element: %.*s", len, atom);
 }

 static size_t expand_format(struct strbuf *sb, const char *start, void *data)
 {
 	const char *end;

 	if (*start != '(')
 		return 0;
 	end = strchr(start + 1, ')');
 	if (!end)
 		die("format element '%s' does not end in ')'", start);

 	expand_atom(sb, start + 1, end - start - 1, data);

 	return end - start + 1;
 }

 static void batch_write(struct batch_options *opt, const void *data, int len)
 {
 	if (opt->buffer_output) {
 		if (fwrite(data, 1, len, stdout) != len)
 			die_errno("unable to write to stdout");
 	} else
 		write_or_die(1, data, len);
 }

 static void print_object_or_die(struct batch_options *opt, struct expand_data *data)
 {
 	const unsigned char *sha1 = data->sha1;

 	assert(data->info.typep);

 	if (data->type == OBJ_BLOB) {
 		if (opt->buffer_output)
 			fflush(stdout);
 		if (stream_blob_to_fd(1, sha1, NULL, 0) < 0)
 			die("unable to stream %s to stdout", sha1_to_hex(sha1));
 	}
 	else {
 		enum object_type type;
 		unsigned long size;
 		void *contents;

 		contents = read_sha1_file(sha1, &type, &size);
 		if (!contents)
 			die("object %s disappeared", sha1_to_hex(sha1));
 		if (type != data->type)
 			die("object %s changed type!?", sha1_to_hex(sha1));
 		if (data->info.sizep && size != data->size)
 			die("object %s changed size!?", sha1_to_hex(sha1));

 		batch_write(opt, contents, size);
 		free(contents);
 	}
 }

 static void batch_object_write(const char *obj_name, struct batch_options *opt,
 			       struct expand_data *data)
 {
 	struct strbuf buf = STRBUF_INIT;

 	if (!data->skip_object_info &&
 	    sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
 		printf("%s missing\n", obj_name ? obj_name : sha1_to_hex(data->sha1));
 		fflush(stdout);
 		return;
 	}

 	strbuf_expand(&buf, opt->format, expand_format, data);
 	strbuf_addch(&buf, '\n');
 	batch_write(opt, buf.buf, buf.len);
 	strbuf_release(&buf);

 	if (opt->print_contents) {
 		print_object_or_die(opt, data);
 		batch_write(opt, "\n", 1);
 	}
 }

 static void batch_one_object(const char *obj_name, struct batch_options *opt,
 			     struct expand_data *data)
 {
 	struct object_context ctx;
 	int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
 	enum follow_symlinks_result result;

 	result = get_sha1_with_context(obj_name, flags, data->sha1, &ctx);
 	if (result != FOUND) {
 		switch (result) {
 		case MISSING_OBJECT:
 			printf("%s missing\n", obj_name);
 			break;
 		case DANGLING_SYMLINK:
 			printf("dangling %"PRIuMAX"\n%s\n",
 			       (uintmax_t)strlen(obj_name), obj_name);
 			break;
 		case SYMLINK_LOOP:
 			printf("loop %"PRIuMAX"\n%s\n",
 			       (uintmax_t)strlen(obj_name), obj_name);
 			break;
 		case NOT_DIR:
 			printf("notdir %"PRIuMAX"\n%s\n",
 			       (uintmax_t)strlen(obj_name), obj_name);
 			break;
 		default:
 			die("BUG: unknown get_sha1_with_context result %d\n",
 			       result);
 			break;
 		}
 		fflush(stdout);
 		return;
 	}

 	if (ctx.mode == 0) {
 		printf("symlink %"PRIuMAX"\n%s\n",
 		       (uintmax_t)ctx.symlink_path.len,
 		       ctx.symlink_path.buf);
 		fflush(stdout);
 		return;
 	}

 	batch_object_write(obj_name, opt, data);
 }

 struct object_cb_data {
 	struct batch_options *opt;
 	struct expand_data *expand;
 };

 static void batch_object_cb(const unsigned char sha1[20], void *vdata)
 {
 	struct object_cb_data *data = vdata;
 	hashcpy(data->expand->sha1, sha1);
 	batch_object_write(NULL, data->opt, data->expand);
 }

 static int batch_loose_object(const unsigned char *sha1,
 			      const char *path,
 			      void *data)
 {
 	sha1_array_append(data, sha1);
 	return 0;
 }

 static int batch_packed_object(const unsigned char *sha1,
 			       struct packed_git *pack,
 			       uint32_t pos,
 			       void *data)
 {
 	sha1_array_append(data, sha1);
 	return 0;
 }

 static int batch_objects(struct batch_options *opt)
 {
 	struct strbuf buf = STRBUF_INIT;
 	struct expand_data data;
 	int save_warning;
 	int retval = 0;

 	if (!opt->format)
 		opt->format = "%(objectname) %(objecttype) %(objectsize)";

 	/*
 	 * Expand once with our special mark_query flag, which will prime the
 	 * object_info to be handed to sha1_object_info_extended for each
 	 * object.
 	 */
 	memset(&data, 0, sizeof(data));
 	data.mark_query = 1;
 	strbuf_expand(&buf, opt->format, expand_format, &data);
 	data.mark_query = 0;

 	if (opt->all_objects) {
 		struct object_info empty;
 		memset(&empty, 0, sizeof(empty));
 		if (!memcmp(&data.info, &empty, sizeof(empty)))
 			data.skip_object_info = 1;
 	}

 	/*
 	 * If we are printing out the object, then always fill in the type,
 	 * since we will want to decide whether or not to stream.
 	 */
 	if (opt->print_contents)
 		data.info.typep = &data.type;

 	if (opt->all_objects) {
 		struct sha1_array sa = SHA1_ARRAY_INIT;
 		struct object_cb_data cb;

 		for_each_loose_object(batch_loose_object, &sa, 0);
 		for_each_packed_object(batch_packed_object, &sa, 0);

 		cb.opt = opt;
 		cb.expand = &data;
 		sha1_array_for_each_unique(&sa, batch_object_cb, &cb);

 		sha1_array_clear(&sa);
 		return 0;
 	}

 	/*
 	 * We are going to call get_sha1 on a potentially very large number of
 	 * objects. In most large cases, these will be actual object sha1s. The
 	 * cost to double-check that each one is not also a ref (just so we can
 	 * warn) ends up dwarfing the actual cost of the object lookups
 	 * themselves. We can work around it by just turning off the warning.
 	 */
 	save_warning = warn_on_object_refname_ambiguity;
 	warn_on_object_refname_ambiguity = 0;

 	while (strbuf_getline(&buf, stdin) != EOF) {
 		if (data.split_on_whitespace) {
 			/*
 			 * Split at first whitespace, tying off the beginning
 			 * of the string and saving the remainder (or NULL) in
 			 * data.rest.
 			 */
 			char *p = strpbrk(buf.buf, " \t");
 			if (p) {
 				while (*p && strchr(" \t", *p))
 					*p++ = '\0';
 			}
 			data.rest = p;
 		}

 		batch_one_object(buf.buf, opt, &data);
 	}

 	strbuf_release(&buf);
 	warn_on_object_refname_ambiguity = save_warning;
 	return retval;
 }

 static const char * const cat_file_usage[] = {
 	N_("git cat-file (-t [--allow-unknown-type]|-s [--allow-unknown-type]|-e|-p|<type>|--textconv) <object>"),
 	N_("git cat-file (--batch | --batch-check) [--follow-symlinks]"),
 	NULL
 };

 static int git_cat_file_config(const char *var, const char *value, void *cb)
 {
 	if (userdiff_config(var, value) < 0)
 		return -1;

 	return git_default_config(var, value, cb);
 }

 static int batch_option_callback(const struct option *opt,
 				 const char *arg,
 				 int unset)
 {
 	struct batch_options *bo = opt->value;

 	if (bo->enabled) {
 		return 1;
 	}

 	bo->enabled = 1;
 	bo->print_contents = !strcmp(opt->long_name, "batch");
 	bo->format = arg;

 	return 0;
 }

 int cmd_cat_file(int argc, const char **argv, const char *prefix)
 {
 	int opt = 0;
 	const char *exp_type = NULL, *obj_name = NULL;
 	struct batch_options batch = {0};
 	int unknown_type = 0;

 	const struct option options[] = {
 		OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
 		OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
 		OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
 		OPT_CMDMODE('e', NULL, &opt,
 			    N_("exit with zero when there's no error"), 'e'),
 		OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
 		OPT_CMDMODE(0, "textconv", &opt,
 			    N_("for blob objects, run textconv on object's content"), 'c'),
 		OPT_BOOL(0, "allow-unknown-type", &unknown_type,
 			  N_("allow -s and -t to work with broken/corrupt objects")),
 		OPT_BOOL(0, "buffer", &batch.buffer_output, N_("buffer --batch output")),
 		{ OPTION_CALLBACK, 0, "batch", &batch, "format",
 			N_("show info and content of objects fed from the standard input"),
 			PARSE_OPT_OPTARG, batch_option_callback },
 		{ OPTION_CALLBACK, 0, "batch-check", &batch, "format",
 			N_("show info about objects fed from the standard input"),
 			PARSE_OPT_OPTARG, batch_option_callback },
 		OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
 			 N_("follow in-tree symlinks (used with --batch or --batch-check)")),
 		OPT_BOOL(0, "batch-all-objects", &batch.all_objects,
 			 N_("show all objects with --batch or --batch-check")),
 		OPT_END()
 	};

 	git_config(git_cat_file_config, NULL);

 	batch.buffer_output = -1;
 	argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);

 	if (opt) {
 		if (argc == 1)
 			obj_name = argv[0];
 		else
 			usage_with_options(cat_file_usage, options);
 	}
 	if (!opt && !batch.enabled) {
 		if (argc == 2) {
 			exp_type = argv[0];
 			obj_name = argv[1];
 		} else
 			usage_with_options(cat_file_usage, options);
 	}
 	if (batch.enabled && (opt || argc)) {
 		usage_with_options(cat_file_usage, options);
 	}

 	if ((batch.follow_symlinks || batch.all_objects) && !batch.enabled) {
 		usage_with_options(cat_file_usage, options);
 	}

 	if (batch.buffer_output < 0)
 		batch.buffer_output = batch.all_objects;

 	if (batch.enabled)
 		return batch_objects(&batch);

 	if (unknown_type && opt != 't' && opt != 's')
 		die("git cat-file --allow-unknown-type: use with -s or -t");
 	return cat_one_file(opt, exp_type, obj_name, unknown_type);
 }
	/*
	* GIT - The information manager from hell
	*
	* Copyright (C) Linus Torvalds, 2005
	*/
	#include "cache.h"
	#include "builtin.h"
	#include "parse-options.h"
	#include "userdiff.h"
	#include "streaming.h"
	#include "tree-walk.h"
	#include "sha1-array.h"

	struct batch_options {
	int enabled;
	int follow_symlinks;
	int print_contents;
	int buffer_output;
	int all_objects;
	const char *format;
	};

	static int cat_one_file(int opt, const char exp_type, const char obj_name,
	int unknown_type)
	{
	unsigned char sha1[20];
	enum object_type type;
	char *buf;
	unsigned long size;
	struct object_context obj_context;
	struct object_info oi = {NULL};
	struct strbuf sb = STRBUF_INIT;
	unsigned flags = LOOKUP_REPLACE_OBJECT;

	if (unknown_type)
	flags \|= LOOKUP_UNKNOWN_OBJECT;

	if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
	die("Not a valid object name %s", obj_name);

	buf = NULL;
	switch (opt) {
	case 't':
	oi.typename = &sb;
	if (sha1_object_info_extended(sha1, &oi, flags) < 0)
	die("git cat-file: could not get object info");
	if (sb.len) {
	printf("%s\n", sb.buf);
	strbuf_release(&sb);
	return 0;
	}
	break;

	case 's':
	oi.sizep = &size;
	if (sha1_object_info_extended(sha1, &oi, flags) < 0)
	die("git cat-file: could not get object info");
	printf("%lu\n", size);
	return 0;

	case 'e':
	return !has_sha1_file(sha1);

	case 'c':
	if (!obj_context.path[0])
	die("git cat-file --textconv %s: <object> must be <sha1:path>",
	obj_name);

	if (textconv_object(obj_context.path, obj_context.mode, sha1, 1, &buf, &size))
	break;

	case 'p':
	type = sha1_object_info(sha1, NULL);
	if (type < 0)
	die("Not a valid object name %s", obj_name);

	/* custom pretty-print here */
	if (type == OBJ_TREE) {
	const char *ls_args[3] = { NULL };
	ls_args[0] = "ls-tree";
	ls_args[1] = obj_name;
	return cmd_ls_tree(2, ls_args, NULL);
	}

	if (type == OBJ_BLOB)
	return stream_blob_to_fd(1, sha1, NULL, 0);
	buf = read_sha1_file(sha1, &type, &size);
	if (!buf)
	die("Cannot read object %s", obj_name);

	/* otherwise just spit out the data */
	break;

	case 0:
	if (type_from_string(exp_type) == OBJ_BLOB) {
	unsigned char blob_sha1[20];
	if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
	char *buffer = read_sha1_file(sha1, &type, &size);
	const char *target;
	if (!skip_prefix(buffer, "object ", &target) \|\|
	get_sha1_hex(target, blob_sha1))
	die("%s not a valid tag", sha1_to_hex(sha1));
	free(buffer);
	} else
	hashcpy(blob_sha1, sha1);

	if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
	return stream_blob_to_fd(1, blob_sha1, NULL, 0);
	/*
	* we attempted to dereference a tag to a blob
	* and failed; there may be new dereference
	* mechanisms this code is not aware of.
	* fall-back to the usual case.
	*/
	}
	buf = read_object_with_reference(sha1, exp_type, &size, NULL);
	break;

	default:
	die("git cat-file: unknown option: %s", exp_type);
	}

	if (!buf)
	die("git cat-file %s: bad file", obj_name);

	write_or_die(1, buf, size);
	return 0;
	}

	struct expand_data {
	unsigned char sha1[20];
	enum object_type type;
	unsigned long size;
	unsigned long disk_size;
	const char *rest;
	unsigned char delta_base_sha1[20];

	/*
	* If mark_query is true, we do not expand anything, but rather
	* just mark the object_info with items we wish to query.
	*/
	int mark_query;

	/*
	* Whether to split the input on whitespace before feeding it to
	* get_sha1; this is decided during the mark_query phase based on
	* whether we have a %(rest) token in our format.
	*/
	int split_on_whitespace;

	/*
	* After a mark_query run, this object_info is set up to be
	* passed to sha1_object_info_extended. It will point to the data
	* elements above, so you can retrieve the response from there.
	*/
	struct object_info info;

	/*
	* This flag will be true if the requested batch format and options
	* don't require us to call sha1_object_info, which can then be
	* optimized out.
	*/
	unsigned skip_object_info : 1;
	};

	static int is_atom(const char atom, const char s, int slen)
	{
	int alen = strlen(atom);
	return alen == slen && !memcmp(atom, s, alen);
	}

	static void expand_atom(struct strbuf sb, const char atom, int len,
	void *vdata)
	{
	struct expand_data *data = vdata;

	if (is_atom("objectname", atom, len)) {
	if (!data->mark_query)
	strbuf_addstr(sb, sha1_to_hex(data->sha1));
	} else if (is_atom("objecttype", atom, len)) {
	if (data->mark_query)
	data->info.typep = &data->type;
	else
	strbuf_addstr(sb, typename(data->type));
	} else if (is_atom("objectsize", atom, len)) {
	if (data->mark_query)
	data->info.sizep = &data->size;
	else
	strbuf_addf(sb, "%lu", data->size);
	} else if (is_atom("objectsize:disk", atom, len)) {
	if (data->mark_query)
	data->info.disk_sizep = &data->disk_size;
	else
	strbuf_addf(sb, "%lu", data->disk_size);
	} else if (is_atom("rest", atom, len)) {
	if (data->mark_query)
	data->split_on_whitespace = 1;
	else if (data->rest)
	strbuf_addstr(sb, data->rest);
	} else if (is_atom("deltabase", atom, len)) {
	if (data->mark_query)
	data->info.delta_base_sha1 = data->delta_base_sha1;
	else
	strbuf_addstr(sb, sha1_to_hex(data->delta_base_sha1));
	} else
	die("unknown format element: %.*s", len, atom);
	}

	static size_t expand_format(struct strbuf sb, const char start, void *data)
	{
	const char *end;

	if (*start != '(')
	return 0;
	end = strchr(start + 1, ')');
	if (!end)
	die("format element '%s' does not end in ')'", start);

	expand_atom(sb, start + 1, end - start - 1, data);

	return end - start + 1;
	}

	static void batch_write(struct batch_options opt, const void data, int len)
	{
	if (opt->buffer_output) {
	if (fwrite(data, 1, len, stdout) != len)
	die_errno("unable to write to stdout");
	} else
	write_or_die(1, data, len);
	}

	static void print_object_or_die(struct batch_options opt, struct expand_data data)
	{
	const unsigned char *sha1 = data->sha1;

	assert(data->info.typep);

	if (data->type == OBJ_BLOB) {
	if (opt->buffer_output)
	fflush(stdout);
	if (stream_blob_to_fd(1, sha1, NULL, 0) < 0)
	die("unable to stream %s to stdout", sha1_to_hex(sha1));
	}
	else {
	enum object_type type;
	unsigned long size;
	void *contents;

	contents = read_sha1_file(sha1, &type, &size);
	if (!contents)
	die("object %s disappeared", sha1_to_hex(sha1));
	if (type != data->type)
	die("object %s changed type!?", sha1_to_hex(sha1));
	if (data->info.sizep && size != data->size)
	die("object %s changed size!?", sha1_to_hex(sha1));

	batch_write(opt, contents, size);
	free(contents);
	}
	}

	static void batch_object_write(const char obj_name, struct batch_options opt,
	struct expand_data *data)
	{
	struct strbuf buf = STRBUF_INIT;

	if (!data->skip_object_info &&
	sha1_object_info_extended(data->sha1, &data->info, LOOKUP_REPLACE_OBJECT) < 0) {
	printf("%s missing\n", obj_name ? obj_name : sha1_to_hex(data->sha1));
	fflush(stdout);
	return;
	}

	strbuf_expand(&buf, opt->format, expand_format, data);
	strbuf_addch(&buf, '\n');
	batch_write(opt, buf.buf, buf.len);
	strbuf_release(&buf);

	if (opt->print_contents) {
	print_object_or_die(opt, data);
	batch_write(opt, "\n", 1);
	}
	}

	static void batch_one_object(const char obj_name, struct batch_options opt,
	struct expand_data *data)
	{
	struct object_context ctx;
	int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
	enum follow_symlinks_result result;

	result = get_sha1_with_context(obj_name, flags, data->sha1, &ctx);
	if (result != FOUND) {
	switch (result) {
	case MISSING_OBJECT:
	printf("%s missing\n", obj_name);
	break;
	case DANGLING_SYMLINK:
	printf("dangling %"PRIuMAX"\n%s\n",
	(uintmax_t)strlen(obj_name), obj_name);
	break;
	case SYMLINK_LOOP:
	printf("loop %"PRIuMAX"\n%s\n",
	(uintmax_t)strlen(obj_name), obj_name);
	break;
	case NOT_DIR:
	printf("notdir %"PRIuMAX"\n%s\n",
	(uintmax_t)strlen(obj_name), obj_name);
	break;
	default:
	die("BUG: unknown get_sha1_with_context result %d\n",
	result);
	break;
	}
	fflush(stdout);
	return;
	}

	if (ctx.mode == 0) {
	printf("symlink %"PRIuMAX"\n%s\n",
	(uintmax_t)ctx.symlink_path.len,
	ctx.symlink_path.buf);
	fflush(stdout);
	return;
	}

	batch_object_write(obj_name, opt, data);
	}

	struct object_cb_data {
	struct batch_options *opt;
	struct expand_data *expand;
	};

	static void batch_object_cb(const unsigned char sha1[20], void *vdata)
	{
	struct object_cb_data *data = vdata;
	hashcpy(data->expand->sha1, sha1);
	batch_object_write(NULL, data->opt, data->expand);
	}

	static int batch_loose_object(const unsigned char *sha1,
	const char *path,
	void *data)
	{
	sha1_array_append(data, sha1);
	return 0;
	}

	static int batch_packed_object(const unsigned char *sha1,
	struct packed_git *pack,
	uint32_t pos,
	void *data)
	{
	sha1_array_append(data, sha1);
	return 0;
	}

	static int batch_objects(struct batch_options *opt)
	{
	struct strbuf buf = STRBUF_INIT;
	struct expand_data data;
	int save_warning;
	int retval = 0;

	if (!opt->format)
	opt->format = "%(objectname) %(objecttype) %(objectsize)";

	/*
	* Expand once with our special mark_query flag, which will prime the
	* object_info to be handed to sha1_object_info_extended for each
	* object.
	*/
	memset(&data, 0, sizeof(data));
	data.mark_query = 1;
	strbuf_expand(&buf, opt->format, expand_format, &data);
	data.mark_query = 0;

	if (opt->all_objects) {
	struct object_info empty;
	memset(&empty, 0, sizeof(empty));
	if (!memcmp(&data.info, &empty, sizeof(empty)))
	data.skip_object_info = 1;
	}

	/*
	* If we are printing out the object, then always fill in the type,
	* since we will want to decide whether or not to stream.
	*/
	if (opt->print_contents)
	data.info.typep = &data.type;

	if (opt->all_objects) {
	struct sha1_array sa = SHA1_ARRAY_INIT;
	struct object_cb_data cb;

	for_each_loose_object(batch_loose_object, &sa, 0);
	for_each_packed_object(batch_packed_object, &sa, 0);

	cb.opt = opt;
	cb.expand = &data;
	sha1_array_for_each_unique(&sa, batch_object_cb, &cb);

	sha1_array_clear(&sa);
	return 0;
	}

	/*
	* We are going to call get_sha1 on a potentially very large number of
	* objects. In most large cases, these will be actual object sha1s. The
	* cost to double-check that each one is not also a ref (just so we can
	* warn) ends up dwarfing the actual cost of the object lookups
	* themselves. We can work around it by just turning off the warning.
	*/
	save_warning = warn_on_object_refname_ambiguity;
	warn_on_object_refname_ambiguity = 0;

	while (strbuf_getline(&buf, stdin) != EOF) {
	if (data.split_on_whitespace) {
	/*
	* Split at first whitespace, tying off the beginning
	* of the string and saving the remainder (or NULL) in
	* data.rest.
	*/
	char *p = strpbrk(buf.buf, " \t");
	if (p) {
	while (p && strchr(" \t", p))
	*p++ = '\0';
	}
	data.rest = p;
	}

	batch_one_object(buf.buf, opt, &data);
	}

	strbuf_release(&buf);
	warn_on_object_refname_ambiguity = save_warning;
	return retval;
	}

	static const char * const cat_file_usage[] = {
	N_("git cat-file (-t [--allow-unknown-type]\|-s [--allow-unknown-type]\|-e\|-p\|<type>\|--textconv) <object>"),
	N_("git cat-file (--batch \| --batch-check) [--follow-symlinks]"),
	NULL
	};

	static int git_cat_file_config(const char var, const char value, void *cb)
	{
	if (userdiff_config(var, value) < 0)
	return -1;

	return git_default_config(var, value, cb);
	}

	static int batch_option_callback(const struct option *opt,
	const char *arg,
	int unset)
	{
	struct batch_options *bo = opt->value;

	if (bo->enabled) {
	return 1;
	}

	bo->enabled = 1;
	bo->print_contents = !strcmp(opt->long_name, "batch");
	bo->format = arg;

	return 0;
	}

	int cmd_cat_file(int argc, const char *argv, const char prefix)
	{
	int opt = 0;
	const char exp_type = NULL, obj_name = NULL;
	struct batch_options batch = {0};
	int unknown_type = 0;

	const struct option options[] = {
	OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
	OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
	OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
	OPT_CMDMODE('e', NULL, &opt,
	N_("exit with zero when there's no error"), 'e'),
	OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
	OPT_CMDMODE(0, "textconv", &opt,
	N_("for blob objects, run textconv on object's content"), 'c'),
	OPT_BOOL(0, "allow-unknown-type", &unknown_type,
	N_("allow -s and -t to work with broken/corrupt objects")),
	OPT_BOOL(0, "buffer", &batch.buffer_output, N_("buffer --batch output")),
	{ OPTION_CALLBACK, 0, "batch", &batch, "format",
	N_("show info and content of objects fed from the standard input"),
	PARSE_OPT_OPTARG, batch_option_callback },
	{ OPTION_CALLBACK, 0, "batch-check", &batch, "format",
	N_("show info about objects fed from the standard input"),
	PARSE_OPT_OPTARG, batch_option_callback },
	OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
	N_("follow in-tree symlinks (used with --batch or --batch-check)")),
	OPT_BOOL(0, "batch-all-objects", &batch.all_objects,
	N_("show all objects with --batch or --batch-check")),
	OPT_END()
	};

	git_config(git_cat_file_config, NULL);

	batch.buffer_output = -1;
	argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);

	if (opt) {
	if (argc == 1)
	obj_name = argv[0];
	else
	usage_with_options(cat_file_usage, options);
	}
	if (!opt && !batch.enabled) {
	if (argc == 2) {
	exp_type = argv[0];
	obj_name = argv[1];
	} else
	usage_with_options(cat_file_usage, options);
	}
	if (batch.enabled && (opt \|\| argc)) {
	usage_with_options(cat_file_usage, options);
	}

	if ((batch.follow_symlinks \|\| batch.all_objects) && !batch.enabled) {
	usage_with_options(cat_file_usage, options);
	}

	if (batch.buffer_output < 0)
	batch.buffer_output = batch.all_objects;

	if (batch.enabled)
	return batch_objects(&batch);

	if (unknown_type && opt != 't' && opt != 's')
	die("git cat-file --allow-unknown-type: use with -s or -t");
	return cat_one_file(opt, exp_type, obj_name, unknown_type);
	}