ll-merge.con commit Merge branch 'sg/describe-contains' (e95c3fb)
   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 or common ancestor for an internal merge.
  51         */
  52        if (opts->virtual_ancestor) {
  53                stolen = orig;
  54        } else {
  55                switch (opts->variant) {
  56                default:
  57                        warning("Cannot merge binary files: %s (%s vs. %s)",
  58                                path, name1, name2);
  59                        /* fallthru */
  60                case XDL_MERGE_FAVOR_OURS:
  61                        stolen = src1;
  62                        break;
  63                case XDL_MERGE_FAVOR_THEIRS:
  64                        stolen = src2;
  65                        break;
  66                }
  67        }
  68
  69        result->ptr = stolen->ptr;
  70        result->size = stolen->size;
  71        stolen->ptr = NULL;
  72
  73        /*
  74         * With -Xtheirs or -Xours, we have cleanly merged;
  75         * otherwise we got a conflict.
  76         */
  77        return (opts->variant ? 0 : 1);
  78}
  79
  80static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
  81                        mmbuffer_t *result,
  82                        const char *path,
  83                        mmfile_t *orig, const char *orig_name,
  84                        mmfile_t *src1, const char *name1,
  85                        mmfile_t *src2, const char *name2,
  86                        const struct ll_merge_options *opts,
  87                        int marker_size)
  88{
  89        xmparam_t xmp;
  90        assert(opts);
  91
  92        if (buffer_is_binary(orig->ptr, orig->size) ||
  93            buffer_is_binary(src1->ptr, src1->size) ||
  94            buffer_is_binary(src2->ptr, src2->size)) {
  95                return ll_binary_merge(drv_unused, result,
  96                                       path,
  97                                       orig, orig_name,
  98                                       src1, name1,
  99                                       src2, name2,
 100                                       opts, marker_size);
 101        }
 102
 103        memset(&xmp, 0, sizeof(xmp));
 104        xmp.level = XDL_MERGE_ZEALOUS;
 105        xmp.favor = opts->variant;
 106        xmp.xpp.flags = opts->xdl_opts;
 107        if (git_xmerge_style >= 0)
 108                xmp.style = git_xmerge_style;
 109        if (marker_size > 0)
 110                xmp.marker_size = marker_size;
 111        xmp.ancestor = orig_name;
 112        xmp.file1 = name1;
 113        xmp.file2 = name2;
 114        return xdl_merge(orig, src1, src2, &xmp, result);
 115}
 116
 117static int ll_union_merge(const struct ll_merge_driver *drv_unused,
 118                          mmbuffer_t *result,
 119                          const char *path_unused,
 120                          mmfile_t *orig, const char *orig_name,
 121                          mmfile_t *src1, const char *name1,
 122                          mmfile_t *src2, const char *name2,
 123                          const struct ll_merge_options *opts,
 124                          int marker_size)
 125{
 126        /* Use union favor */
 127        struct ll_merge_options o;
 128        assert(opts);
 129        o = *opts;
 130        o.variant = XDL_MERGE_FAVOR_UNION;
 131        return ll_xdl_merge(drv_unused, result, path_unused,
 132                            orig, NULL, src1, NULL, src2, NULL,
 133                            &o, marker_size);
 134}
 135
 136#define LL_BINARY_MERGE 0
 137#define LL_TEXT_MERGE 1
 138#define LL_UNION_MERGE 2
 139static struct ll_merge_driver ll_merge_drv[] = {
 140        { "binary", "built-in binary merge", ll_binary_merge },
 141        { "text", "built-in 3-way text merge", ll_xdl_merge },
 142        { "union", "built-in union merge", ll_union_merge },
 143};
 144
 145static void create_temp(mmfile_t *src, char *path)
 146{
 147        int fd;
 148
 149        strcpy(path, ".merge_file_XXXXXX");
 150        fd = xmkstemp(path);
 151        if (write_in_full(fd, src->ptr, src->size) != src->size)
 152                die_errno("unable to write temp-file");
 153        close(fd);
 154}
 155
 156/*
 157 * User defined low-level merge driver support.
 158 */
 159static int ll_ext_merge(const struct ll_merge_driver *fn,
 160                        mmbuffer_t *result,
 161                        const char *path,
 162                        mmfile_t *orig, const char *orig_name,
 163                        mmfile_t *src1, const char *name1,
 164                        mmfile_t *src2, const char *name2,
 165                        const struct ll_merge_options *opts,
 166                        int marker_size)
 167{
 168        char temp[4][50];
 169        struct strbuf cmd = STRBUF_INIT;
 170        struct strbuf_expand_dict_entry dict[6];
 171        struct strbuf path_sq = STRBUF_INIT;
 172        const char *args[] = { NULL, NULL };
 173        int status, fd, i;
 174        struct stat st;
 175        assert(opts);
 176
 177        sq_quote_buf(&path_sq, path);
 178        dict[0].placeholder = "O"; dict[0].value = temp[0];
 179        dict[1].placeholder = "A"; dict[1].value = temp[1];
 180        dict[2].placeholder = "B"; dict[2].value = temp[2];
 181        dict[3].placeholder = "L"; dict[3].value = temp[3];
 182        dict[4].placeholder = "P"; dict[4].value = path_sq.buf;
 183        dict[5].placeholder = NULL; dict[5].value = NULL;
 184
 185        if (fn->cmdline == NULL)
 186                die("custom merge driver %s lacks command line.", fn->name);
 187
 188        result->ptr = NULL;
 189        result->size = 0;
 190        create_temp(orig, temp[0]);
 191        create_temp(src1, temp[1]);
 192        create_temp(src2, temp[2]);
 193        sprintf(temp[3], "%d", marker_size);
 194
 195        strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
 196
 197        args[0] = cmd.buf;
 198        status = run_command_v_opt(args, RUN_USING_SHELL);
 199        fd = open(temp[1], O_RDONLY);
 200        if (fd < 0)
 201                goto bad;
 202        if (fstat(fd, &st))
 203                goto close_bad;
 204        result->size = st.st_size;
 205        result->ptr = xmalloc(result->size + 1);
 206        if (read_in_full(fd, result->ptr, result->size) != result->size) {
 207                free(result->ptr);
 208                result->ptr = NULL;
 209                result->size = 0;
 210        }
 211 close_bad:
 212        close(fd);
 213 bad:
 214        for (i = 0; i < 3; i++)
 215                unlink_or_warn(temp[i]);
 216        strbuf_release(&cmd);
 217        strbuf_release(&path_sq);
 218        return status;
 219}
 220
 221/*
 222 * merge.default and merge.driver configuration items
 223 */
 224static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
 225static const char *default_ll_merge;
 226
 227static int read_merge_config(const char *var, const char *value, void *cb)
 228{
 229        struct ll_merge_driver *fn;
 230        const char *key, *name;
 231        int namelen;
 232
 233        if (!strcmp(var, "merge.default"))
 234                return git_config_string(&default_ll_merge, var, value);
 235
 236        /*
 237         * We are not interested in anything but "merge.<name>.variable";
 238         * especially, we do not want to look at variables such as
 239         * "merge.summary", "merge.tool", and "merge.verbosity".
 240         */
 241        if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
 242                return 0;
 243
 244        /*
 245         * Find existing one as we might be processing merge.<name>.var2
 246         * after seeing merge.<name>.var1.
 247         */
 248        for (fn = ll_user_merge; fn; fn = fn->next)
 249                if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
 250                        break;
 251        if (!fn) {
 252                fn = xcalloc(1, sizeof(struct ll_merge_driver));
 253                fn->name = xmemdupz(name, namelen);
 254                fn->fn = ll_ext_merge;
 255                *ll_user_merge_tail = fn;
 256                ll_user_merge_tail = &(fn->next);
 257        }
 258
 259        if (!strcmp("name", key))
 260                return git_config_string(&fn->description, var, value);
 261
 262        if (!strcmp("driver", key)) {
 263                if (!value)
 264                        return error("%s: lacks value", var);
 265                /*
 266                 * merge.<name>.driver specifies the command line:
 267                 *
 268                 *      command-line
 269                 *
 270                 * The command-line will be interpolated with the following
 271                 * tokens and is given to the shell:
 272                 *
 273                 *    %O - temporary file name for the merge base.
 274                 *    %A - temporary file name for our version.
 275                 *    %B - temporary file name for the other branches' version.
 276                 *    %L - conflict marker length
 277                 *    %P - the original path (safely quoted for the shell)
 278                 *
 279                 * The external merge driver should write the results in the
 280                 * file named by %A, and signal that it has done with zero exit
 281                 * status.
 282                 */
 283                fn->cmdline = xstrdup(value);
 284                return 0;
 285        }
 286
 287        if (!strcmp("recursive", key))
 288                return git_config_string(&fn->recursive, var, value);
 289
 290        return 0;
 291}
 292
 293static void initialize_ll_merge(void)
 294{
 295        if (ll_user_merge_tail)
 296                return;
 297        ll_user_merge_tail = &ll_user_merge;
 298        git_config(read_merge_config, NULL);
 299}
 300
 301static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
 302{
 303        struct ll_merge_driver *fn;
 304        const char *name;
 305        int i;
 306
 307        initialize_ll_merge();
 308
 309        if (ATTR_TRUE(merge_attr))
 310                return &ll_merge_drv[LL_TEXT_MERGE];
 311        else if (ATTR_FALSE(merge_attr))
 312                return &ll_merge_drv[LL_BINARY_MERGE];
 313        else if (ATTR_UNSET(merge_attr)) {
 314                if (!default_ll_merge)
 315                        return &ll_merge_drv[LL_TEXT_MERGE];
 316                else
 317                        name = default_ll_merge;
 318        }
 319        else
 320                name = merge_attr;
 321
 322        for (fn = ll_user_merge; fn; fn = fn->next)
 323                if (!strcmp(fn->name, name))
 324                        return fn;
 325
 326        for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
 327                if (!strcmp(ll_merge_drv[i].name, name))
 328                        return &ll_merge_drv[i];
 329
 330        /* default to the 3-way */
 331        return &ll_merge_drv[LL_TEXT_MERGE];
 332}
 333
 334static int git_path_check_merge(const char *path, struct git_attr_check check[2])
 335{
 336        if (!check[0].attr) {
 337                check[0].attr = git_attr("merge");
 338                check[1].attr = git_attr("conflict-marker-size");
 339        }
 340        return git_check_attr(path, 2, check);
 341}
 342
 343static void normalize_file(mmfile_t *mm, const char *path)
 344{
 345        struct strbuf strbuf = STRBUF_INIT;
 346        if (renormalize_buffer(path, mm->ptr, mm->size, &strbuf)) {
 347                free(mm->ptr);
 348                mm->size = strbuf.len;
 349                mm->ptr = strbuf_detach(&strbuf, NULL);
 350        }
 351}
 352
 353int ll_merge(mmbuffer_t *result_buf,
 354             const char *path,
 355             mmfile_t *ancestor, const char *ancestor_label,
 356             mmfile_t *ours, const char *our_label,
 357             mmfile_t *theirs, const char *their_label,
 358             const struct ll_merge_options *opts)
 359{
 360        static struct git_attr_check check[2];
 361        static const struct ll_merge_options default_opts;
 362        const char *ll_driver_name = NULL;
 363        int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 364        const struct ll_merge_driver *driver;
 365
 366        if (!opts)
 367                opts = &default_opts;
 368
 369        if (opts->renormalize) {
 370                normalize_file(ancestor, path);
 371                normalize_file(ours, path);
 372                normalize_file(theirs, path);
 373        }
 374        if (!git_path_check_merge(path, check)) {
 375                ll_driver_name = check[0].value;
 376                if (check[1].value) {
 377                        marker_size = atoi(check[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        if (opts->virtual_ancestor && driver->recursive)
 384                driver = find_ll_merge_driver(driver->recursive);
 385        return driver->fn(driver, result_buf, path, ancestor, ancestor_label,
 386                          ours, our_label, theirs, their_label,
 387                          opts, marker_size);
 388}
 389
 390int ll_merge_marker_size(const char *path)
 391{
 392        static struct git_attr_check check;
 393        int marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 394
 395        if (!check.attr)
 396                check.attr = git_attr("conflict-marker-size");
 397        if (!git_check_attr(path, 1, &check) && check.value) {
 398                marker_size = atoi(check.value);
 399                if (marker_size <= 0)
 400                        marker_size = DEFAULT_CONFLICT_MARKER_SIZE;
 401        }
 402        return marker_size;
 403}