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

#define BATCH 1
#define BATCH_CHECK 2

static int cat_one_file(int opt, const char *exp_type, const char *obj_name)
{
        unsigned char sha1[20];
        enum object_type type;
        char *buf;
        unsigned long size;
        struct object_context obj_context;

        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':
                type = sha1_object_info(sha1, NULL);
                if (type > 0) {
                        printf("%s\n", typename(type));
                        return 0;
                }
                break;

        case 's':
                type = sha1_object_info(sha1, &size);
                if (type > 0) {
                        printf("%lu\n", size);
                        return 0;
                }
                break;

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

        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 '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))
                        die("git cat-file --textconv: unable to run textconv on %s",
                            obj_name);
                break;

        case 0:
                if (type_from_string(exp_type) == OBJ_BLOB) {
                        unsigned char blob_sha1[20];
                        if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
                                enum object_type type;
                                unsigned long size;
                                char *buffer = read_sha1_file(sha1, &type, &size);
                                if (memcmp(buffer, "object ", 7) ||
                                    get_sha1_hex(buffer + 7, 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;
}

static int batch_one_object(const char *obj_name, int print_contents)
{
        unsigned char sha1[20];
        enum object_type type = 0;
        unsigned long size;
        void *contents = NULL;

        if (!obj_name)
           return 1;

        if (get_sha1(obj_name, sha1)) {
                printf("%s missing\n", obj_name);
                fflush(stdout);
                return 0;
        }

        if (print_contents == BATCH)
                contents = read_sha1_file(sha1, &type, &size);
        else
                type = sha1_object_info(sha1, &size);

        if (type <= 0) {
                printf("%s missing\n", obj_name);
                fflush(stdout);
                if (print_contents == BATCH)
                        free(contents);
                return 0;
        }

        printf("%s %s %lu\n", sha1_to_hex(sha1), typename(type), size);
        fflush(stdout);

        if (print_contents == BATCH) {
                write_or_die(1, contents, size);
                printf("\n");
                fflush(stdout);
                free(contents);
        }

        return 0;
}

static int batch_objects(int print_contents)
{
        struct strbuf buf = STRBUF_INIT;

        while (strbuf_getline(&buf, stdin, '\n') != EOF) {
                int error = batch_one_object(buf.buf, print_contents);
                if (error)
                        return error;
        }

        return 0;
}

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

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

        const struct option options[] = {
                OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
                OPT_SET_INT('t', NULL, &opt, N_("show object type"), 't'),
                OPT_SET_INT('s', NULL, &opt, N_("show object size"), 's'),
                OPT_SET_INT('e', NULL, &opt,
                            N_("exit with zero when there's no error"), 'e'),
                OPT_SET_INT('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
                OPT_SET_INT(0, "textconv", &opt,
                            N_("for blob objects, run textconv on object's content"), 'c'),
                OPT_SET_INT(0, "batch", &batch,
                            N_("show info and content of objects fed from the standard input"),
                            BATCH),
                OPT_SET_INT(0, "batch-check", &batch,
                            N_("show info about objects fed from the standard input"),
                            BATCH_CHECK),
                OPT_END()
        };

        git_config(git_cat_file_config, NULL);

        if (argc != 3 && argc != 2)
                usage_with_options(cat_file_usage, options);

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

        if (batch)
                return batch_objects(batch);

        return cat_one_file(opt, exp_type, obj_name);
}