ll-merge.con commit Merge branch 'nd/conditional-config-include' (4b7989b)
   1/*
   2 * Low level 3-way in-core file merge.
   3 *
   4 * Copyright (c) 2007 Junio C Hamano
   5 */
   6
   7#include "cache.h"
   8#include "attr.h"
   9#include "xdiff-interface.h"
  10#include "run-command.h"
  11#include "ll-merge.h"
  12#include "quote.h"
  13
  14struct ll_merge_driver;
  15
  16typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
  17                           mmbuffer_t *result,
  18                           const char *path,
  19                           mmfile_t *orig, const char *orig_name,
  20                           mmfile_t *src1, const char *name1,
  21                           mmfile_t *src2, const char *name2,
  22                           const struct ll_merge_options *opts,
  23                           int marker_size);
  24
  25struct ll_merge_driver {
  26        const char *name;
  27        const char *description;
  28        ll_merge_fn fn;
  29        const char *recursive;
  30        struct ll_merge_driver *next;
  31        char *cmdline;
  32};
  33
  34/*
  35 * Built-in low-levels
  36 */
  37static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
  38                           mmbuffer_t *result,
  39                           const char *path,
  40                           mmfile_t *orig, const char *orig_name,
  41                           mmfile_t *src1, const char *name1,
  42                           mmfile_t *src2, const char *name2,
  43                           const struct ll_merge_options *opts,
  44                           int marker_size)
  45{
  46        mmfile_t *stolen;
  47        assert(opts);
  48
  49        /*
  50         * The tentative merge result is the common ancestor for an
  51         * internal merge.  For the final merge, it is "ours" by
  52         * default but -Xours/-Xtheirs can tweak the choice.
  53         */
  54        if (opts->virtual_ancestor) {
  55                stolen = orig;
  56        } else {
  57                switch (opts->variant) {
  58                default:
  59                        warning("Cannot merge binary files: %s (%s vs. %s)",
  60                                path, name1, name2);
  61                        /* fallthru */
  62                case XDL_MERGE_FAVOR_OURS:
  63                        stolen = src1;
  64                        break;
  65                case XDL_MERGE_FAVOR_THEIRS:
  66                        stolen = src2;
  67                        break;
  68                }
  69        }
  70
  71        result->ptr = stolen->ptr;
  72        result->size = stolen->size;
  73        stolen->ptr = NULL;
  74
  75        /*
  76         * With -Xtheirs or -Xours, we have cleanly merged;
  77         * otherwise we got a conflict.
  78         */
  79        return (opts->variant ? 0 : 1);
  80}
  81
  82static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
  83                        mmbuffer_t *result,
  84                        const char *path,
  85                        mmfile_t *orig, const char *orig_name,
  86                        mmfile_t *src1, const char *name1,
  87                        mmfile_t *src2, const char *name2,
  88                        const struct ll_merge_options *opts,
  89                        int marker_size)
  90{
  91        xmparam_t xmp;
  92        assert(opts);
  93
  94        if (orig->size > MAX_XDIFF_SIZE ||
  95            src1->size > MAX_XDIFF_SIZE ||
  96            src2->size > MAX_XDIFF_SIZE ||
  97            buffer_is_binary(orig->ptr, orig->size) ||
  98            buffer_is_binary(src1->ptr, src1->size) ||
  99            buffer_is_binary(src2->ptr, src2->size)) {
 100                return ll_binary_merge(drv_unused, result,
 101                                       path,
 102                                       orig, orig_name,
 103                                       src1, name1,
 104                                       src2, name2,
 105                                       opts, marker_size);
 106        }
 107
 108        memset(&xmp, 0, sizeof(xmp));
 109        xmp.level = XDL_MERGE_ZEALOUS;
 110        xmp.favor = opts->variant;
 111        xmp.xpp.flags = opts->xdl_opts;
 112        if (git_xmerge_style >= 0)
 113                xmp.style = git_xmerge_style;
 114        if (marker_size > 0)
 115                xmp.marker_size = marker_size;
 116        xmp.ancestor = orig_name;
 117        xmp.file1 = name1;
 118        xmp.file2 = name2;
 119        return xdl_merge(orig, src1, src2, &xmp, result);
 120}
 121
 122static int ll_union_merge(const struct ll_merge_driver *drv_unused,
 123                          mmbuffer_t *result,
 124                          const char *path_unused,
 125                          mmfile_t *orig, const char *orig_name,
 126                          mmfile_t *src1, const char *name1,
 127                          mmfile_t *src2, const char *name2,
 128                          const struct ll_merge_options *opts,
 129                          int marker_size)
 130{
 131        /* Use union favor */
 132        struct ll_merge_options o;
 133        assert(opts);
 134        o = *opts;
 135        o.variant = XDL_MERGE_FAVOR_UNION;
 136        return ll_xdl_merge(drv_unused, result, path_unused,
 137                            orig, NULL, src1, NULL, src2, NULL,
 138                            &o, marker_size);
 139}
 140
 141#define LL_BINARY_MERGE 0
 142#define LL_TEXT_MERGE 1
 143#define LL_UNION_MERGE 2
 144static struct ll_merge_driver ll_merge_drv[] = {
 145        { "binary", "built-in binary merge", ll_binary_merge },
 146        { "text", "built-in 3-way text merge", ll_xdl_merge },
 147        { "union", "built-in union merge", ll_union_merge },
 148};
 149
 150static void create_temp(mmfile_t *src, char *path, size_t len)
 151{
 152        int fd;
 153
 154        xsnprintf(path, len, ".merge_file_XXXXXX");
 155        fd = xmkstemp(path);
 156        if (write_in_full(fd, src->ptr, src->size) != src->size)
 157                die_errno("unable to write temp-file");
 158        close(fd);
 159}
 160
 161/*
 162 * User defined low-level merge driver support.
 163 */
 164static int ll_ext_merge(const struct ll_merge_driver *fn,
 165                        mmbuffer_t *result,
 166                        const char *path,
 167                        mmfile_t *orig, const char *orig_name,
 168                        mmfile_t *src1, const char *name1,
 169                        mmfile_t *src2, const char *name2,
 170                        const struct ll_merge_options *opts,
 171                        int marker_size)
 172{
 173        char temp[4][50];
 174        struct strbuf cmd = STRBUF_INIT;
 175        struct strbuf_expand_dict_entry dict[6];
 176        struct strbuf path_sq = STRBUF_INIT;
 177        const char *args[] = { NULL, NULL };
 178        int status, fd, i;
 179        struct stat st;
 180        assert(opts);
 181
 182        sq_quote_buf(&path_sq, path);
 183        dict[0].placeholder = "O"; dict[0].value = temp[0];
 184        dict[1].placeholder = "A"; dict[1].value = temp[1];
 185        dict[2].placeholder = "B"; dict[2].value = temp[2];
 186        dict[3].placeholder = "L"; dict[3].value = temp[3];
 187        dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
 188        dict[5].placeholder = NULL; dict[5].value = NULL;
 189
 190        if (fn->cmdline == NULL)
 191                die("custom merge driver %s lacks command line.", fn->name);
 192
 193        result->ptr = NULL;
 194        result->size = 0;
 195        create_temp(orig, temp[0], sizeof(temp[0]));
 196        create_temp(src1, temp[1], sizeof(temp[1]));
 197        create_temp(src2, temp[2], sizeof(temp[2]));
 198        xsnprintf(temp[3], sizeof(temp[3]), "%d", marker_size);
 199
 200        strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
 201
 202        args[0] = cmd.buf;
 203        status = run_command_v_opt(args, RUN_USING_SHELL);
 204        fd = open(temp[1], O_RDONLY);
 205        if (fd < 0)
 206                goto bad;
 207        if (fstat(fd, &st))
 208                goto close_bad;
 209        result->size = st.st_size;
 210        result->ptr = xmallocz(result->size);
 211        if (read_in_full(fd, result->ptr, result->size) != result->size) {
 212                free(result->ptr);
 213                result->ptr = NULL;
 214                result->size = 0;
 215        }
 216 close_bad:
 217        close(fd);
 218 bad:
 219        for (i = 0; i < 3; i++)
 220                unlink_or_warn(temp[i]);
 221        strbuf_release(&cmd);
 222        strbuf_release(&path_sq);
 223        return status;
 224}
 225
 226/*
 227 * merge.default and merge.driver configuration items
 228 */
 229static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
 230static const char *default_ll_merge;
 231
 232static int read_merge_config(const char *var, const char *value, void *cb)
 233{
 234        struct ll_merge_driver *fn;
 235        const char *key, *name;
 236        int namelen;
 237
 238        if (!strcmp(var, "merge.default"))
 239                return git_config_string(&default_ll_merge, var, value);
 240
 241        /*
 242         * We are not interested in anything but "merge.<name>.variable";
 243         * especially, we do not want to look at variables such as
 244         * "merge.summary", "merge.tool", and "merge.verbosity".
 245         */
 246        if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
 247                return 0;
 248
 249        /*
 250         * Find existing one as we might be processing merge.<name>.var2
 251         * after seeing merge.<name>.var1.
 252         */
 253        for (fn = ll_user_merge; fn; fn = fn->next)
 254                if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
 255                        break;
 256        if (!fn) {
 257                fn = xcalloc(1, sizeof(struct ll_merge_driver));
 258                fn->name = xmemdupz(name, namelen);
 259                fn->fn = ll_ext_merge;
 260                *ll_user_merge_tail = fn;
 261                ll_user_merge_tail = &(fn->next);
 262        }
 263
 264        if (!strcmp("name", key))
 265                return git_config_string(&fn->description, var, value);
 266
 267        if (!strcmp("driver", key)) {
 268                if (!value)
 269                        return error("%s: lacks value", var);
 270                /*
 271                 * merge.<name>.driver specifies the command line:
 272                 *
 273                 *      command-line
 274                 *
 275                 * The command-line will be interpolated with the following
 276                 * tokens and is given to the shell:
 277                 *
 278                 *    %O - temporary file name for the merge base.
 279                 *    %A - temporary file name for our version.
 280                 *    %B - temporary file name for the other branches' version.
 281                 *    %L - conflict marker length
 282                 *    %P - the original path (safely quoted for the shell)
 283                 *
 284                 * The external merge driver should write the results in the
 285                 * file named by %A, and signal that it has done with zero exit
 286                 * status.
 287                 */
 288                fn->cmdline = xstrdup(value);
 289                return 0;
 290        }
 291
 292        if (!strcmp("recursive", key))
 293                return git_config_string(&fn->recursive, var, value);
 294
 295        return 0;
 296}
 297
 298static void initialize_ll_merge(void)
 299{
 300        if (ll_user_merge_tail)
 301                return;
 302        ll_user_merge_tail = &ll_user_merge;
 303        git_config(read_merge_config, NULL);
 304}
 305
 306static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
 307{
 308        struct ll_merge_driver *fn;
 309        const char *name;
 310        int i;
 311
 312        initialize_ll_merge();
 313
 314        if (ATTR_TRUE(merge_attr))
 315                return &ll_merge_drv[LL_TEXT_MERGE];
 316        else if (ATTR_FALSE(merge_attr))
 317                return &ll_merge_drv[LL_BINARY_MERGE];
 318        else if (ATTR_UNSET(merge_attr)) {
 319                if (!default_ll_merge)
 320                        return &ll_merge_drv[LL_TEXT_MERGE];
 321                else
 322                        name = default_ll_merge;
 323        }
 324        else
 325                name = merge_attr;
 326
 327        for (fn = ll_user_merge; fn; fn = fn->next)
 328                if (!strcmp(fn->name, name))
 329                        return fn;
 330
 331        for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
 332                if (!strcmp(ll_merge_drv[i].name, name))
 333                        return &ll_merge_drv[i];
 334
 335        /* default to the 3-way */
 336        return &ll_merge_drv[LL_TEXT_MERGE];
 337}
 338
 339static void normalize_file(mmfile_t *mm, const char *path)
 340{
 341        struct strbuf strbuf = STRBUF_INIT;
 342        if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {
 343                free(mm->ptr);
 344                mm->size = strbuf.len;
 345                mm->ptr = strbuf_detach(&strbuf, NULL);
 346        }
 347}
 348
 349int ll_merge(mmbuffer_t *result_buf,
 350             const char *path,
 351             mmfile_t *ancestor, const char *ancestor_label,
 352             mmfile_t *ours, const char *our_label,
 353             mmfile_t *theirs, const char *their_label,
 354             const struct ll_merge_options *opts)
 355{
 356        static struct attr_check *check;
 357        static const struct ll_merge_options default_opts;
 358        const char *ll_driver_name = NULL;
 359        int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 360        const struct ll_merge_driver *driver;
 361
 362        if (!opts)
 363                opts = &default_opts;
 364
 365        if (opts->renormalize) {
 366                normalize_file(ancestor, path);
 367                normalize_file(ours, path);
 368                normalize_file(theirs, path);
 369        }
 370
 371        if (!check)
 372                check = attr_check_initl("merge", "conflict-marker-size", NULL);
 373
 374        if (!git_check_attr(path, check)) {
 375                ll_driver_name = check->items[0].value;
 376                if (check->items[1].value) {
 377                        marker_size = atoi(check->items[1].value);
 378                        if (marker_size <= 0)
 379                                marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 380                }
 381        }
 382        driver = find_ll_merge_driver(ll_driver_name);
 383
 384        if (opts->virtual_ancestor) {
 385                if (driver->recursive)
 386                        driver = find_ll_merge_driver(driver->recursive);
 387                marker_size += 2;
 388        }
 389        return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
 390                          ours, our_label, theirs, their_label,
 391                          opts, marker_size);
 392}
 393
 394int ll_merge_marker_size(const char *path)
 395{
 396        static struct attr_check *check;
 397        int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 398
 399        if (!check)
 400                check = attr_check_initl("conflict-marker-size", NULL);
 401        if (!git_check_attr(path, check) && check->items[0].value) {
 402                marker_size = atoi(check->items[0].value);
 403                if (marker_size <= 0)
 404                        marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 405        }
 406        return marker_size;
 407}