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 * pretty-printed for human editing based on its type.
 193 */
 194static void export_object(const unsigned char *sha1, const char *filename)
 195{
 196        const char *argv[] = { "--no-replace-objects", "cat-file", "-p", NULL, NULL };
 197        struct child_process cmd = { argv };
 198        int fd;
 199
 200        fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC, 0666);
 201        if (fd < 0)
 202                die_errno("unable to open %s for writing", filename);
 203
 204        argv[3] = sha1_to_hex(sha1);
 205        cmd.git_cmd = 1;
 206        cmd.out = fd;
 207
 208        if (run_command(&cmd))
 209                die("cat-file reported failure");
 210
 211        close(fd);
 212}
 213
 214/*
 215 * Read a previously-exported (and possibly edited) object back from "filename",
 216 * interpreting it as "type", and writing the result to the object database.
 217 * The sha1 of the written object is returned via sha1.
 218 */
 219static void import_object(unsigned char *sha1, enum object_type type,
 220                          const char *filename)
 221{
 222        int fd;
 223
 224        fd = open(filename, O_RDONLY);
 225        if (fd < 0)
 226                die_errno("unable to open %s for reading", filename);
 227
 228        if (type == OBJ_TREE) {
 229                const char *argv[] = { "mktree", NULL };
 230                struct child_process cmd = { argv };
 231                struct strbuf result = STRBUF_INIT;
 232
 233                cmd.argv = argv;
 234                cmd.git_cmd = 1;
 235                cmd.in = fd;
 236                cmd.out = -1;
 237
 238                if (start_command(&cmd))
 239                        die("unable to spawn mktree");
 240
 241                if (strbuf_read(&result, cmd.out, 41) < 0)
 242                        die_errno("unable to read from mktree");
 243                close(cmd.out);
 244
 245                if (finish_command(&cmd))
 246                        die("mktree reported failure");
 247                if (get_sha1_hex(result.buf, sha1) < 0)
 248                        die("mktree did not return an object name");
 249
 250                strbuf_release(&result);
 251        } else {
 252                struct stat st;
 253                int flags = HASH_FORMAT_CHECK | HASH_WRITE_OBJECT;
 254
 255                if (fstat(fd, &st) < 0)
 256                        die_errno("unable to fstat %s", filename);
 257                if (index_fd(sha1, fd, &st, type, NULL, flags) < 0)
 258                        die("unable to write object to database");
 259                /* index_fd close()s fd for us */
 260        }
 261
 262        /*
 263         * No need to close(fd) here; both run-command and index-fd
 264         * will have done it for us.
 265         */
 266}
 267
 268static int edit_and_replace(const char *object_ref, int force)
 269{
 270        char *tmpfile = git_pathdup("REPLACE_EDITOBJ");
 271        enum object_type type;
 272        unsigned char old[20], new[20], prev[20];
 273        char ref[PATH_MAX];
 274
 275        if (get_sha1(object_ref, old) < 0)
 276                die("Not a valid object name: '%s'", object_ref);
 277
 278        type = sha1_object_info(old, NULL);
 279        if (type < 0)
 280                die("unable to get object type for %s", sha1_to_hex(old));
 281
 282        check_ref_valid(old, prev, ref, sizeof(ref), force);
 283
 284        export_object(old, tmpfile);
 285        if (launch_editor(tmpfile, NULL, NULL) < 0)
 286                die("editing object file failed");
 287        import_object(new, type, tmpfile);
 288
 289        free(tmpfile);
 290
 291        if (!hashcmp(old, new))
 292                return error("new object is the same as the old one: '%s'", sha1_to_hex(old));
 293
 294        return replace_object_sha1(object_ref, old, "replacement", new, force);
 295}
 296
 297int cmd_replace(int argc, const char **argv, const char *prefix)
 298{
 299        int force = 0;
 300        const char *format = NULL;
 301        enum {
 302                MODE_UNSPECIFIED = 0,
 303                MODE_LIST,
 304                MODE_DELETE,
 305                MODE_EDIT,
 306                MODE_REPLACE
 307        } cmdmode = MODE_UNSPECIFIED;
 308        struct option options[] = {
 309                OPT_CMDMODE('l', "list", &cmdmode, N_("list replace refs"), MODE_LIST),
 310                OPT_CMDMODE('d', "delete", &cmdmode, N_("delete replace refs"), MODE_DELETE),
 311                OPT_CMDMODE('e', "edit", &cmdmode, N_("edit existing object"), MODE_EDIT),
 312                OPT_BOOL('f', "force", &force, N_("replace the ref if it exists")),
 313                OPT_STRING(0, "format", &format, N_("format"), N_("use this format")),
 314                OPT_END()
 315        };
 316
 317        check_replace_refs = 0;
 318
 319        argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
 320
 321        if (!cmdmode)
 322                cmdmode = argc ? MODE_REPLACE : MODE_LIST;
 323
 324        if (format && cmdmode != MODE_LIST)
 325                usage_msg_opt("--format cannot be used when not listing",
 326                              git_replace_usage, options);
 327
 328        if (force && cmdmode != MODE_REPLACE && cmdmode != MODE_EDIT)
 329                usage_msg_opt("-f only makes sense when writing a replacement",
 330                              git_replace_usage, options);
 331
 332        switch (cmdmode) {
 333        case MODE_DELETE:
 334                if (argc < 1)
 335                        usage_msg_opt("-d needs at least one argument",
 336                                      git_replace_usage, options);
 337                return for_each_replace_name(argv, delete_replace_ref);
 338
 339        case MODE_REPLACE:
 340                if (argc != 2)
 341                        usage_msg_opt("bad number of arguments",
 342                                      git_replace_usage, options);
 343                return replace_object(argv[0], argv[1], force);
 344
 345        case MODE_EDIT:
 346                if (argc != 1)
 347                        usage_msg_opt("-e needs exactly one argument",
 348                                      git_replace_usage, options);
 349                return edit_and_replace(argv[0], force);
 350
 351        case MODE_LIST:
 352                if (argc > 1)
 353                        usage_msg_opt("only one pattern can be given with -l",
 354                                      git_replace_usage, options);
 355                return list_replace_refs(argv[0], format);
 356
 357        default:
 358                die("BUG: invalid cmdmode %d", (int)cmdmode);
 359        }
 360}