Andrew's git - gitweb.git/blob

   1/*
   2 * Builtin "git replace"
   3 *
   4 * Copyright (c) 2008 Christian Couder <chriscool@tuxfamily.org>
   5 *
   6 * Based on builtin/tag.c by Kristian Høgsberg <krh@redhat.com>
   7 * and Carlos Rica <jasampler@gmail.com> that was itself based on
   8 * git-tag.sh and mktag.c by Linus Torvalds.
   9 */
  10
  11#include "cache.h"
  12#include "builtin.h"
  13#include "refs.h"
  14#include "parse-options.h"
  15#include "run-command.h"
  16
  17static const char * const git_replace_usage[] = {
  18        N_("git replace [-f] <object> <replacement>"),
  19        N_("git replace [-f] --edit <object>"),
  20        N_("git replace -d <object>..."),
  21        N_("git replace [--format=<format>] [-l [<pattern>]]"),
  22        NULL
  23};
  24
  25enum replace_format {
  26        REPLACE_FORMAT_SHORT,
  27        REPLACE_FORMAT_MEDIUM,
  28        REPLACE_FORMAT_LONG
  29};
  30
  31struct show_data {
  32        const char *pattern;
  33        enum replace_format format;
  34};
  35
  36static int show_reference(const char *refname, const unsigned char *sha1,
  37                          int flag, void *cb_data)
  38{
  39        struct show_data *data = cb_data;
  40
  41        if (!wildmatch(data->pattern, refname, 0, NULL)) {
  42                if (data->format == REPLACE_FORMAT_SHORT)
  43                        printf("%s\n", refname);
  44                else if (data->format == REPLACE_FORMAT_MEDIUM)
  45                        printf("%s -> %s\n", refname, sha1_to_hex(sha1));
  46                else { /* data->format == REPLACE_FORMAT_LONG */
  47                        unsigned char object[20];
  48                        enum object_type obj_type, repl_type;
  49
  50                        if (get_sha1(refname, object))
  51                                return error("Failed to resolve '%s' as a valid ref.", refname);
  52
  53                        obj_type = sha1_object_info(object, NULL);
  54                        repl_type = sha1_object_info(sha1, NULL);
  55
  56                        printf("%s (%s) -> %s (%s)\n", refname, typename(obj_type),
  57                               sha1_to_hex(sha1), typename(repl_type));
  58                }
  59        }
  60
  61        return 0;
  62}
  63
  64static int list_replace_refs(const char *pattern, const char *format)
  65{
  66        struct show_data data;
  67
  68        if (pattern == NULL)
  69                pattern = "*";
  70        data.pattern = pattern;
  71
  72        if (format == NULL || *format == '\0' || !strcmp(format, "short"))
  73                data.format = REPLACE_FORMAT_SHORT;
  74        else if (!strcmp(format, "medium"))
  75                data.format = REPLACE_FORMAT_MEDIUM;
  76        else if (!strcmp(format, "long"))
  77                data.format = REPLACE_FORMAT_LONG;
  78        else
  79                die("invalid replace format '%s'\n"
  80                    "valid formats are 'short', 'medium' and 'long'\n",
  81                    format);
  82
  83        for_each_replace_ref(show_reference, (void *) &data);
  84
  85        return 0;
  86}
  87
  88typedef int (*each_replace_name_fn)(const char *name, const char *ref,
  89                                    const unsigned char *sha1);
  90
  91static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
  92{
  93        const char **p, *full_hex;
  94        char ref[PATH_MAX];
  95        int had_error = 0;
  96        unsigned char sha1[20];
  97
  98        for (p = argv; *p; p++) {
  99                if (get_sha1(*p, sha1)) {
 100                        error("Failed to resolve '%s' as a valid ref.", *p);
 101                        had_error = 1;
 102                        continue;
 103                }
 104                full_hex = sha1_to_hex(sha1);
 105                snprintf(ref, sizeof(ref), "refs/replace/%s", full_hex);
 106                /* read_ref() may reuse the buffer */
 107                full_hex = ref + strlen("refs/replace/");
 108                if (read_ref(ref, sha1)) {
 109                        error("replace ref '%s' not found.", full_hex);
 110                        had_error = 1;
 111                        continue;
 112                }
 113                if (fn(full_hex, ref, sha1))
 114                        had_error = 1;
 115        }
 116        return had_error;
 117}
 118
 119static int delete_replace_ref(const char *name, const char *ref,
 120                              const unsigned char *sha1)
 121{
 122        if (delete_ref(ref, sha1, 0))
 123                return 1;
 124        printf("Deleted replace ref '%s'\n", name);
 125        return 0;
 126}
 127
 128static void check_ref_valid(unsigned char object[20],
 129                            unsigned char prev[20],
 130                            char *ref,
 131                            int ref_size,
 132                            int force)
 133{
 134        if (snprintf(ref, ref_size,
 135                     "refs/replace/%s",
 136                     sha1_to_hex(object)) > ref_size - 1)
 137                die("replace ref name too long: %.*s...", 50, ref);
 138        if (check_refname_format(ref, 0))
 139                die("'%s' is not a valid ref name.", ref);
 140
 141        if (read_ref(ref, prev))
 142                hashclr(prev);
 143        else if (!force)
 144                die("replace ref '%s' already exists", ref);
 145}
 146
 147static int replace_object_sha1(const char *object_ref,
 148                               unsigned char object[20],
 149                               const char *replace_ref,
 150                               unsigned char repl[20],
 151                               int force)
 152{
 153        unsigned char prev[20];
 154        enum object_type obj_type, repl_type;
 155        char ref[PATH_MAX];
 156        struct ref_lock *lock;
 157
 158        obj_type = sha1_object_info(object, NULL);
 159        repl_type = sha1_object_info(repl, NULL);
 160        if (!force && obj_type != repl_type)
 161                die("Objects must be of the same type.\n"
 162                    "'%s' points to a replaced object of type '%s'\n"
 163                    "while '%s' points to a replacement object of type '%s'.",
 164                    object_ref, typename(obj_type),
 165                    replace_ref, typename(repl_type));
 166
 167        check_ref_valid(object, prev, ref, sizeof(ref), force);
 168
 169        lock = lock_any_ref_for_update(ref, prev, 0, NULL);
 170        if (!lock)
 171                die("%s: cannot lock the ref", ref);
 172        if (write_ref_sha1(lock, repl, NULL) < 0)
 173                die("%s: cannot update the ref", ref);
 174
 175        return 0;
 176}
 177
 178static int replace_object(const char *object_ref, const char *replace_ref, int force)
 179{
 180        unsigned char object[20], repl[20];
 181
 182        if (get_sha1(object_ref, object))
 183                die("Failed to resolve '%s' as a valid ref.", object_ref);
 184        if (get_sha1(replace_ref, repl))
 185                die("Failed to resolve '%s' as a valid ref.", replace_ref);
 186
 187        return replace_object_sha1(object_ref, object, replace_ref, repl, force);
 188}
 189
 190/*
 191 * Write the contents of the object named by "sha1" to the file "filename".
 192 * If "raw" is true, then the object's raw contents are printed according to
 193 * "type". Otherwise, we pretty-print the contents for human editing.
 194 */
 195static void export_object(const unsigned char *sha1, enum object_type type,
 196                          int raw, const char *filename)
 197{
 198        struct child_process cmd = { NULL };
 199        int fd;
 200
 201        fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 202        if (fd < 0)
 203                die_errno("unable to open %s for writing", filename);
 204
 205        argv_array_push(&cmd.args, "--no-replace-objects");
 206        argv_array_push(&cmd.args, "cat-file");
 207        if (raw)
 208                argv_array_push(&cmd.args, typename(type));
 209        else
 210                argv_array_push(&cmd.args, "-p");
 211        argv_array_push(&cmd.args, sha1_to_hex(sha1));
 212        cmd.git_cmd = 1;
 213        cmd.out = fd;
 214
 215        if (run_command(&cmd))
 216                die("cat-file reported failure");
 217}
 218
 219/*
 220 * Read a previously-exported (and possibly edited) object back from "filename",
 221 * interpreting it as "type", and writing the result to the object database.
 222 * The sha1 of the written object is returned via sha1.
 223 */
 224static void import_object(unsigned char *sha1, enum object_type type,
 225                          int raw, const char *filename)
 226{
 227        int fd;
 228
 229        fd = open(filename, O_RDONLY);
 230        if (fd < 0)
 231                die_errno("unable to open %s for reading", filename);
 232
 233        if (!raw && type == OBJ_TREE) {
 234                const char *argv[] = { "mktree", NULL };
 235                struct child_process cmd = { argv };
 236                struct strbuf result = STRBUF_INIT;
 237
 238                cmd.argv = argv;
 239                cmd.git_cmd = 1;
 240                cmd.in = fd;
 241                cmd.out = -1;
 242
 243                if (start_command(&cmd))
 244                        die("unable to spawn mktree");
 245
 246                if (strbuf_read(&result, cmd.out, 41) < 0)
 247                        die_errno("unable to read from mktree");
 248                close(cmd.out);
 249
 250                if (finish_command(&cmd))
 251                        die("mktree reported failure");
 252                if (get_sha1_hex(result.buf, sha1) < 0)
 253                        die("mktree did not return an object name");
 254
 255                strbuf_release(&result);
 256        } else {
 257                struct stat st;
 258                int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
 259
 260                if (fstat(fd, &st) < 0)
 261                        die_errno("unable to fstat %s", filename);
 262                if (index_fd(sha1, fd, &st, type, NULL, flags) < 0)
 263                        die("unable to write object to database");
 264                /* index_fd close()s fd for us */
 265        }
 266
 267        /*
 268         * No need to close(fd) here; both run-command and index-fd
 269         * will have done it for us.
 270         */
 271}
 272
 273static int edit_and_replace(const char *object_ref, int force, int raw)
 274{
 275        char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
 276        enum object_type type;
 277        unsigned char old[20], new[20], prev[20];
 278        char ref[PATH_MAX];
 279
 280        if (get_sha1(object_ref, old) < 0)
 281                die("Not a valid object name: '%s'", object_ref);
 282
 283        type = sha1_object_info(old, NULL);
 284        if (type < 0)
 285                die("unable to get object type for %s", sha1_to_hex(old));
 286
 287        check_ref_valid(old, prev, ref, sizeof(ref), force);
 288
 289        export_object(old, type, raw, tmpfile);
 290        if (launch_editor(tmpfile, NULL, NULL) < 0)
 291                die("editing object file failed");
 292        import_object(new, type, raw, tmpfile);
 293
 294        free(tmpfile);
 295
 296        if (!hashcmp(old, new))
 297                return error("new object is the same as the old one: '%s'", sha1_to_hex(old));
 298
 299        return replace_object_sha1(object_ref, old, "replacement", new, force);
 300}
 301
 302int cmd_replace(int argc, const char **argv, const char *prefix)
 303{
 304        int force = 0;
 305        int raw = 0;
 306        const char *format = NULL;
 307        enum {
 308                MODE_UNSPECIFIED = 0,
 309                MODE_LIST,
 310                MODE_DELETE,
 311                MODE_EDIT,
 312                MODE_REPLACE
 313        } cmdmode = MODE_UNSPECIFIED;
 314        struct option options[] = {
 315                OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
 316                OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
 317                OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
 318                OPT_BOOL('f', "force", &force, N_("replace the ref if it exists")),
 319                OPT_BOOL(0, "raw", &raw, N_("do not pretty-print contents for --edit")),
 320                OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
 321                OPT_END()
 322        };
 323
 324        check_replace_refs = 0;
 325
 326        argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
 327
 328        if (!cmdmode)
 329                cmdmode = argc ? MODE_REPLACE : MODE_LIST;
 330
 331        if (format && cmdmode != MODE_LIST)
 332                usage_msg_opt("--format cannot be used when not listing",
 333                              git_replace_usage, options);
 334
 335        if (force && cmdmode != MODE_REPLACE && cmdmode != MODE_EDIT)
 336                usage_msg_opt("-f only makes sense when writing a replacement",
 337                              git_replace_usage, options);
 338
 339        if (raw && cmdmode != MODE_EDIT)
 340                usage_msg_opt("--raw only makes sense with --edit",
 341                              git_replace_usage, options);
 342
 343        switch (cmdmode) {
 344        case MODE_DELETE:
 345                if (argc < 1)
 346                        usage_msg_opt("-d needs at least one argument",
 347                                      git_replace_usage, options);
 348                return for_each_replace_name(argv, delete_replace_ref);
 349
 350        case MODE_REPLACE:
 351                if (argc != 2)
 352                        usage_msg_opt("bad number of arguments",
 353                                      git_replace_usage, options);
 354                return replace_object(argv[0], argv[1], force);
 355
 356        case MODE_EDIT:
 357                if (argc != 1)
 358                        usage_msg_opt("-e needs exactly one argument",
 359                                      git_replace_usage, options);
 360                return edit_and_replace(argv[0], force, raw);
 361
 362        case MODE_LIST:
 363                if (argc > 1)
 364                        usage_msg_opt("only one pattern can be given with -l",
 365                                      git_replace_usage, options);
 366                return list_replace_refs(argv[0], format);
 367
 368        default:
 369                die("BUG: invalid cmdmode %d", (int)cmdmode);
 370        }
 371}