/*
 * GIT - The information manager from hell
 *
 * Copyright (C) Linus Torvalds, 2005
 */
#define USE_THE_INDEX_COMPATIBILITY_MACROS
#include "cache.h"
#include "config.h"
#include "builtin.h"
#include "diff.h"
#include "parse-options.h"
#include "userdiff.h"
#include "streaming.h"
#include "tree-walk.h"
#include "oid-array.h"
#include "packfile.h"
#include "object-store.h"
#include "promisor-remote.h"
#include "ref-filter.h"

struct batch_options {
	int enabled;
	int follow_symlinks;
	int print_contents;
	int buffer_output;
	int all_objects;
	int unordered;
	int cmdmode; /* may be 'w' or 'c' for --filters or --textconv */
	struct ref_format format;
};

static const char *force_path;

static int filter_object(const char *path, unsigned mode,
			 const struct object_id *oid,
			 char **buf, unsigned long *size)
{
	enum object_type type;

	*buf = read_object_file(oid, &type, size);
	if (!*buf)
		return error(_("cannot read object %s '%s'"),
			     oid_to_hex(oid), path);
	if ((type == OBJ_BLOB) && S_ISREG(mode)) {
		struct strbuf strbuf = STRBUF_INIT;
		struct checkout_metadata meta;

		init_checkout_metadata(&meta, NULL, NULL, oid);
		if (convert_to_working_tree(&the_index, path, *buf, *size, &strbuf, &meta)) {
			free(*buf);
			*size = strbuf.len;
			*buf = strbuf_detach(&strbuf, NULL);
		}
	}

	return 0;
}

static int stream_blob(const struct object_id *oid)
{
	if (stream_blob_to_fd(1, oid, NULL, 0))
		die("unable to stream %s to stdout", oid_to_hex(oid));
	return 0;
}

static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
			int unknown_type)
{
	struct object_id oid;
	enum object_type type;
	char *buf;
	unsigned long size;
	struct object_context obj_context;
	struct object_info oi = OBJECT_INFO_INIT;
	struct strbuf sb = STRBUF_INIT;
	unsigned flags = OBJECT_INFO_LOOKUP_REPLACE;
	const char *path = force_path;

	if (unknown_type)
		flags |= OBJECT_INFO_ALLOW_UNKNOWN_TYPE;

	if (get_oid_with_context(the_repository, obj_name,
				 GET_OID_RECORD_PATH,
				 &oid, &obj_context))
		die("Not a valid object name %s", obj_name);

	if (!path)
		path = obj_context.path;
	if (obj_context.mode == S_IFINVALID)
		obj_context.mode = 0100644;

	buf = NULL;
	switch (opt) {
	case 't':
		oi.type_name = &sb;
		if (oid_object_info_extended(the_repository, &oid, &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 (oid_object_info_extended(the_repository, &oid, &oi, flags) < 0)
			die("git cat-file: could not get object info");
		printf("%"PRIuMAX"\n", (uintmax_t)size);
		return 0;

	case 'e':
		return !has_object_file(&oid);

	case 'w':
		if (!path)
			die("git cat-file --filters %s: <object> must be "
			    "<sha1:path>", obj_name);

		if (filter_object(path, obj_context.mode,
				  &oid, &buf, &size))
			return -1;
		break;

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

		if (textconv_object(the_repository, path, obj_context.mode,
				    &oid, 1, &buf, &size))
			break;
		/* else fallthrough */

	case 'p':
		type = oid_object_info(the_repository, &oid, 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(&oid);
		buf = read_object_file(&oid, &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) {
			struct object_id blob_oid;
			if (oid_object_info(the_repository, &oid, NULL) == OBJ_TAG) {
				char *buffer = read_object_file(&oid, &type,
								&size);
				const char *target;
				if (!skip_prefix(buffer, "object ", &target) ||
				    get_oid_hex(target, &blob_oid))
					die("%s not a valid tag", oid_to_hex(&oid));
				free(buffer);
			} else
				oidcpy(&blob_oid, &oid);

			if (oid_object_info(the_repository, &blob_oid, NULL) == OBJ_BLOB)
				return stream_blob(&blob_oid);
			/*
			 * 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(the_repository,
						 &oid, 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);
	free(buf);
	free(obj_context.path);
	return 0;
}

struct expand_data {
	struct object_id oid;
	const char *rest;
	int split_on_whitespace;
};

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 batch_object_write(const char *obj_name,
			       struct strbuf *scratch,
			       struct batch_options *opt,
			       struct expand_data *data)
{
	int ret;
	struct strbuf err = STRBUF_INIT;
	struct ref_array_item item = { data->oid, data->rest };

	strbuf_reset(scratch);

	ret = format_ref_array_item(&item, &opt->format, scratch, &err);
	if (ret < 0)
		die("%s\n", err.buf);
	if (ret) {
		/* ret > 0 means when the object corresponding to oid
		 * cannot be found in format_ref_array_item(), we only print
		 * the error message.
		 */
		printf("%s\n", err.buf);
		fflush(stdout);
	} else {
		strbuf_addch(scratch, '\n');
		batch_write(opt, scratch->buf, scratch->len);
	}
	free_ref_array_item_value(&item);
	strbuf_release(&err);
}

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

	result = get_oid_with_context(the_repository, obj_name,
				      flags, &data->oid, &ctx);
	if (result != FOUND) {
		switch (result) {
		case MISSING_OBJECT:
			printf("%s missing\n", obj_name);
			break;
		case SHORT_NAME_AMBIGUOUS:
			printf("%s ambiguous\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:
			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;
	}

	if (!has_object_file(&data->oid)) {
		printf("%s missing\n",
		       obj_name ? obj_name : oid_to_hex(&data->oid));
		fflush(stdout);
		return;
	}

	batch_object_write(obj_name, scratch, opt, data);
}

struct object_cb_data {
	struct batch_options *opt;
	struct expand_data *expand;
	struct oidset *seen;
	struct strbuf *scratch;
};

static int batch_object_cb(const struct object_id *oid, void *vdata)
{
	struct object_cb_data *data = vdata;
	oidcpy(&data->expand->oid, oid);
	batch_object_write(NULL, data->scratch, data->opt, data->expand);
	return 0;
}

static int collect_loose_object(const struct object_id *oid,
				const char *path,
				void *data)
{
	oid_array_append(data, oid);
	return 0;
}

static int collect_packed_object(const struct object_id *oid,
				 struct packed_git *pack,
				 uint32_t pos,
				 void *data)
{
	oid_array_append(data, oid);
	return 0;
}

static int batch_unordered_object(const struct object_id *oid, void *vdata)
{
	struct object_cb_data *data = vdata;

	if (oidset_insert(data->seen, oid))
		return 0;

	return batch_object_cb(oid, data);
}

static int batch_unordered_loose(const struct object_id *oid,
				 const char *path,
				 void *data)
{
	return batch_unordered_object(oid, data);
}

static int batch_unordered_packed(const struct object_id *oid,
				  struct packed_git *pack,
				  uint32_t pos,
				  void *data)
{
	return batch_unordered_object(oid, data);
}

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

static int batch_objects(struct batch_options *batch, const struct option *options)
{
	struct strbuf input = STRBUF_INIT;
	struct strbuf output = STRBUF_INIT;
	struct strbuf format = STRBUF_INIT;
	struct expand_data data;
	int save_warning;
	int retval = 0;

	memset(&data, 0, sizeof(data));
	if (batch->format.format)
		strbuf_addstr(&format, batch->format.format);
	else
		strbuf_addstr(&format, "%(objectname) %(objecttype) %(objectsize)");
	if (batch->print_contents)
		strbuf_addstr(&format, "\n%(raw)");
	batch->format.format = format.buf;
	if (verify_ref_format(&batch->format))
		usage_with_options(cat_file_usage, options);

	if (batch->cmdmode || batch->format.use_rest)
		data.split_on_whitespace = 1;

	if (batch->all_objects) {
		struct object_cb_data cb;

		if (has_promisor_remote())
			warning("This repository uses promisor remotes. Some objects may not be loaded.");

		cb.opt = batch;
		cb.expand = &data;
		cb.scratch = &output;

		if (batch->unordered) {
			struct oidset seen = OIDSET_INIT;

			cb.seen = &seen;

			for_each_loose_object(batch_unordered_loose, &cb, 0);
			for_each_packed_object(batch_unordered_packed, &cb,
					       FOR_EACH_OBJECT_PACK_ORDER);

			oidset_clear(&seen);
		} else {
			struct oid_array sa = OID_ARRAY_INIT;

			for_each_loose_object(collect_loose_object, &sa, 0);
			for_each_packed_object(collect_packed_object, &sa, 0);

			oid_array_for_each_unique(&sa, batch_object_cb, &cb);

			oid_array_clear(&sa);
		}

		strbuf_release(&format);
		strbuf_release(&output);
		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(&input, 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(input.buf, " \t");
			if (p) {
				while (*p && strchr(" \t", *p))
					*p++ = '\0';
			}
			data.rest = p;
		}

		batch_one_object(input.buf, &output, batch, &data);
	}

	strbuf_release(&format);
	strbuf_release(&input);
	strbuf_release(&output);
	warn_on_object_refname_ambiguity = save_warning;
	return retval;
}

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;

	BUG_ON_OPT_NEG(unset);

	if (bo->enabled) {
		return error(_("only one batch option may be specified"));
	}

	bo->enabled = 1;
	bo->print_contents = !strcmp(opt->long_name, "batch");
	bo->format.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 = {
		.format = REF_FORMAT_INIT
	};
	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_CMDMODE(0, "filters", &opt,
			    N_("for blob objects, run filters on object's content"), 'w'),
		OPT_STRING(0, "path", &force_path, N_("blob"),
			   N_("use a specific path for --textconv/--filters")),
		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")),
		OPT_CALLBACK_F(0, "batch", &batch, "format",
			N_("show info and content of objects fed from the standard input"),
			PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
			batch_option_callback),
		OPT_CALLBACK_F(0, "batch-check", &batch, "format",
			N_("show info about objects fed from the standard input"),
			PARSE_OPT_OPTARG | PARSE_OPT_NONEG,
			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_BOOL(0, "unordered", &batch.unordered,
			 N_("do not order --batch-all-objects output")),
		OPT_END()
	};

	git_config(git_cat_file_config, NULL);

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

	if (opt) {
		if (batch.enabled && (opt == 'c' || opt == 'w'))
			batch.cmdmode = opt;
		else 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) {
		if (batch.cmdmode != opt || argc)
			usage_with_options(cat_file_usage, options);
		if (batch.cmdmode && batch.all_objects)
			die("--batch-all-objects cannot be combined with "
			    "--textconv nor with --filters");
	}

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

	if (force_path && opt != 'c' && opt != 'w') {
		error("--path=<path> needs --textconv or --filters");
		usage_with_options(cat_file_usage, options);
	}

	if (force_path && batch.enabled) {
		error("--path=<path> incompatible with --batch");
		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, options);

	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);
}