ll-merge.con commit Teach Solaris that _XOPEN_SOURCE=600 really menas XPG6 (30d8080)
   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
  13struct ll_merge_driver;
  14
  15typedef int (*ll_merge_fn)(const struct ll_merge_driver *,
  16                           mmbuffer_t *result,
  17                           const char *path,
  18                           mmfile_t *orig,
  19                           mmfile_t *src1, const char *name1,
  20                           mmfile_t *src2, const char *name2,
  21                           int virtual_ancestor);
  22
  23struct ll_merge_driver {
  24        const char *name;
  25        const char *description;
  26        ll_merge_fn fn;
  27        const char *recursive;
  28        struct ll_merge_driver *next;
  29        char *cmdline;
  30};
  31
  32/*
  33 * Built-in low-levels
  34 */
  35static int ll_binary_merge(const struct ll_merge_driver *drv_unused,
  36                           mmbuffer_t *result,
  37                           const char *path_unused,
  38                           mmfile_t *orig,
  39                           mmfile_t *src1, const char *name1,
  40                           mmfile_t *src2, const char *name2,
  41                           int virtual_ancestor)
  42{
  43        /*
  44         * The tentative merge result is "ours" for the final round,
  45         * or common ancestor for an internal merge.  Still return
  46         * "conflicted merge" status.
  47         */
  48        mmfile_t *stolen = virtual_ancestor ? orig : src1;
  49
  50        result->ptr = stolen->ptr;
  51        result->size = stolen->size;
  52        stolen->ptr = NULL;
  53        return 1;
  54}
  55
  56static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
  57                        mmbuffer_t *result,
  58                        const char *path_unused,
  59                        mmfile_t *orig,
  60                        mmfile_t *src1, const char *name1,
  61                        mmfile_t *src2, const char *name2,
  62                        int virtual_ancestor)
  63{
  64        xpparam_t xpp;
  65        int style = 0;
  66
  67        if (buffer_is_binary(orig->ptr, orig->size) ||
  68            buffer_is_binary(src1->ptr, src1->size) ||
  69            buffer_is_binary(src2->ptr, src2->size)) {
  70                warning("Cannot merge binary files: %s vs. %s\n",
  71                        name1, name2);
  72                return ll_binary_merge(drv_unused, result,
  73                                       path_unused,
  74                                       orig, src1, name1,
  75                                       src2, name2,
  76                                       virtual_ancestor);
  77        }
  78
  79        memset(&xpp, 0, sizeof(xpp));
  80        if (git_xmerge_style >= 0)
  81                style = git_xmerge_style;
  82        return xdl_merge(orig,
  83                         src1, name1,
  84                         src2, name2,
  85                         &xpp, XDL_MERGE_ZEALOUS | style,
  86                         result);
  87}
  88
  89static int ll_union_merge(const struct ll_merge_driver *drv_unused,
  90                          mmbuffer_t *result,
  91                          const char *path_unused,
  92                          mmfile_t *orig,
  93                          mmfile_t *src1, const char *name1,
  94                          mmfile_t *src2, const char *name2,
  95                          int virtual_ancestor)
  96{
  97        char *src, *dst;
  98        long size;
  99        const int marker_size = 7;
 100        int status, saved_style;
 101
 102        /* We have to force the RCS "merge" style */
 103        saved_style = git_xmerge_style;
 104        git_xmerge_style = 0;
 105        status = ll_xdl_merge(drv_unused, result, path_unused,
 106                              orig, src1, NULL, src2, NULL,
 107                              virtual_ancestor);
 108        git_xmerge_style = saved_style;
 109        if (status <= 0)
 110                return status;
 111        size = result->size;
 112        src = dst = result->ptr;
 113        while (size) {
 114                char ch;
 115                if ((marker_size < size) &&
 116                    (*src == '<' || *src == '=' || *src == '>')) {
 117                        int i;
 118                        ch = *src;
 119                        for (i = 0; i < marker_size; i++)
 120                                if (src[i] != ch)
 121                                        goto not_a_marker;
 122                        if (src[marker_size] != '\n')
 123                                goto not_a_marker;
 124                        src += marker_size + 1;
 125                        size -= marker_size + 1;
 126                        continue;
 127                }
 128        not_a_marker:
 129                do {
 130                        ch = *src++;
 131                        *dst++ = ch;
 132                        size--;
 133                } while (ch != '\n' && size);
 134        }
 135        result->size = dst - result->ptr;
 136        return 0;
 137}
 138
 139#define LL_BINARY_MERGE 0
 140#define LL_TEXT_MERGE 1
 141#define LL_UNION_MERGE 2
 142static struct ll_merge_driver ll_merge_drv[] = {
 143        { "binary", "built-in binary merge", ll_binary_merge },
 144        { "text", "built-in 3-way text merge", ll_xdl_merge },
 145        { "union", "built-in union merge", ll_union_merge },
 146};
 147
 148static void create_temp(mmfile_t *src, char *path)
 149{
 150        int fd;
 151
 152        strcpy(path, ".merge_file_XXXXXX");
 153        fd = xmkstemp(path);
 154        if (write_in_full(fd, src->ptr, src->size) != src->size)
 155                die("unable to write temp-file");
 156        close(fd);
 157}
 158
 159/*
 160 * User defined low-level merge driver support.
 161 */
 162static int ll_ext_merge(const struct ll_merge_driver *fn,
 163                        mmbuffer_t *result,
 164                        const char *path,
 165                        mmfile_t *orig,
 166                        mmfile_t *src1, const char *name1,
 167                        mmfile_t *src2, const char *name2,
 168                        int virtual_ancestor)
 169{
 170        char temp[3][50];
 171        struct strbuf cmd = STRBUF_INIT;
 172        struct strbuf_expand_dict_entry dict[] = {
 173                { "O", temp[0] },
 174                { "A", temp[1] },
 175                { "B", temp[2] },
 176                { NULL }
 177        };
 178        struct child_process child;
 179        const char *args[20];
 180        int status, fd, i;
 181        struct stat st;
 182
 183        if (fn->cmdline == NULL)
 184                die("custom merge driver %s lacks command line.", fn->name);
 185
 186        result->ptr = NULL;
 187        result->size = 0;
 188        create_temp(orig, temp[0]);
 189        create_temp(src1, temp[1]);
 190        create_temp(src2, temp[2]);
 191
 192        strbuf_expand(&cmd, fn->cmdline, strbuf_expand_dict_cb, &dict);
 193
 194        memset(&child, 0, sizeof(child));
 195        child.argv = args;
 196        args[0] = "sh";
 197        args[1] = "-c";
 198        args[2] = cmd.buf;
 199        args[3] = NULL;
 200
 201        status = run_command(&child);
 202        if (status < -ERR_RUN_COMMAND_FORK)
 203                ; /* failure in run-command */
 204        else
 205                status = -status;
 206        fd = open(temp[1], O_RDONLY);
 207        if (fd < 0)
 208                goto bad;
 209        if (fstat(fd, &st))
 210                goto close_bad;
 211        result->size = st.st_size;
 212        result->ptr = xmalloc(result->size + 1);
 213        if (read_in_full(fd, result->ptr, result->size) != result->size) {
 214                free(result->ptr);
 215                result->ptr = NULL;
 216                result->size = 0;
 217        }
 218 close_bad:
 219        close(fd);
 220 bad:
 221        for (i = 0; i < 3; i++)
 222                unlink_or_warn(temp[i]);
 223        strbuf_release(&cmd);
 224        return status;
 225}
 226
 227/*
 228 * merge.default and merge.driver configuration items
 229 */
 230static struct ll_merge_driver *ll_user_merge, **ll_user_merge_tail;
 231static const char *default_ll_merge;
 232
 233static int read_merge_config(const char *var, const char *value, void *cb)
 234{
 235        struct ll_merge_driver *fn;
 236        const char *ep, *name;
 237        int namelen;
 238
 239        if (!strcmp(var, "merge.default")) {
 240                if (value)
 241                        default_ll_merge = strdup(value);
 242                return 0;
 243        }
 244
 245        /*
 246         * We are not interested in anything but "merge.<name>.variable";
 247         * especially, we do not want to look at variables such as
 248         * "merge.summary", "merge.tool", and "merge.verbosity".
 249         */
 250        if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
 251                return 0;
 252
 253        /*
 254         * Find existing one as we might be processing merge.<name>.var2
 255         * after seeing merge.<name>.var1.
 256         */
 257        name = var + 6;
 258        namelen = ep - name;
 259        for (fn = ll_user_merge; fn; fn = fn->next)
 260                if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
 261                        break;
 262        if (!fn) {
 263                fn = xcalloc(1, sizeof(struct ll_merge_driver));
 264                fn->name = xmemdupz(name, namelen);
 265                fn->fn = ll_ext_merge;
 266                *ll_user_merge_tail = fn;
 267                ll_user_merge_tail = &(fn->next);
 268        }
 269
 270        ep++;
 271
 272        if (!strcmp("name", ep)) {
 273                if (!value)
 274                        return error("%s: lacks value", var);
 275                fn->description = strdup(value);
 276                return 0;
 277        }
 278
 279        if (!strcmp("driver", ep)) {
 280                if (!value)
 281                        return error("%s: lacks value", var);
 282                /*
 283                 * merge.<name>.driver specifies the command line:
 284                 *
 285                 *      command-line
 286                 *
 287                 * The command-line will be interpolated with the following
 288                 * tokens and is given to the shell:
 289                 *
 290                 *    %O - temporary file name for the merge base.
 291                 *    %A - temporary file name for our version.
 292                 *    %B - temporary file name for the other branches' version.
 293                 *
 294                 * The external merge driver should write the results in the
 295                 * file named by %A, and signal that it has done with zero exit
 296                 * status.
 297                 */
 298                fn->cmdline = strdup(value);
 299                return 0;
 300        }
 301
 302        if (!strcmp("recursive", ep)) {
 303                if (!value)
 304                        return error("%s: lacks value", var);
 305                fn->recursive = strdup(value);
 306                return 0;
 307        }
 308
 309        return 0;
 310}
 311
 312static void initialize_ll_merge(void)
 313{
 314        if (ll_user_merge_tail)
 315                return;
 316        ll_user_merge_tail = &ll_user_merge;
 317        git_config(read_merge_config, NULL);
 318}
 319
 320static const struct ll_merge_driver *find_ll_merge_driver(const char *merge_attr)
 321{
 322        struct ll_merge_driver *fn;
 323        const char *name;
 324        int i;
 325
 326        initialize_ll_merge();
 327
 328        if (ATTR_TRUE(merge_attr))
 329                return &ll_merge_drv[LL_TEXT_MERGE];
 330        else if (ATTR_FALSE(merge_attr))
 331                return &ll_merge_drv[LL_BINARY_MERGE];
 332        else if (ATTR_UNSET(merge_attr)) {
 333                if (!default_ll_merge)
 334                        return &ll_merge_drv[LL_TEXT_MERGE];
 335                else
 336                        name = default_ll_merge;
 337        }
 338        else
 339                name = merge_attr;
 340
 341        for (fn = ll_user_merge; fn; fn = fn->next)
 342                if (!strcmp(fn->name, name))
 343                        return fn;
 344
 345        for (i = 0; i < ARRAY_SIZE(ll_merge_drv); i++)
 346                if (!strcmp(ll_merge_drv[i].name, name))
 347                        return &ll_merge_drv[i];
 348
 349        /* default to the 3-way */
 350        return &ll_merge_drv[LL_TEXT_MERGE];
 351}
 352
 353static const char *git_path_check_merge(const char *path)
 354{
 355        static struct git_attr_check attr_merge_check;
 356
 357        if (!attr_merge_check.attr)
 358                attr_merge_check.attr = git_attr("merge", 5);
 359
 360        if (git_checkattr(path, 1, &attr_merge_check))
 361                return NULL;
 362        return attr_merge_check.value;
 363}
 364
 365int ll_merge(mmbuffer_t *result_buf,
 366             const char *path,
 367             mmfile_t *ancestor,
 368             mmfile_t *ours, const char *our_label,
 369             mmfile_t *theirs, const char *their_label,
 370             int virtual_ancestor)
 371{
 372        const char *ll_driver_name;
 373        const struct ll_merge_driver *driver;
 374
 375        ll_driver_name = git_path_check_merge(path);
 376        driver = find_ll_merge_driver(ll_driver_name);
 377
 378        if (virtual_ancestor && driver->recursive)
 379                driver = find_ll_merge_driver(driver->recursive);
 380        return driver->fn(driver, result_buf, path,
 381                          ancestor,
 382                          ours, our_label,
 383                          theirs, their_label, virtual_ancestor);
 384}