builtin-read-tree.c

   1 /*
   2  * GIT - The information manager from hell
   3  *
   4  * Copyright (C) Linus Torvalds, 2005
   5  */
   6
   7 #include "cache.h"
   8 #include "object.h"
   9 #include "tree.h"
  10 #include "tree-walk.h"
  11 #include "cache-tree.h"
  12 #include "unpack-trees.h"
  13 #include "dir.h"
  14 #include "builtin.h"
  15 #include "parse-options.h"
  16
  17 static int nr_trees;
  18 static struct tree *trees[MAX_UNPACK_TREES];
  19
  20 static int list_tree(unsigned char *sha1)
  21 {
  22         struct tree *tree;
  23
  24         if (nr_trees >= MAX_UNPACK_TREES)
  25                 die("I cannot read more than %d trees", MAX_UNPACK_TREES);
  26         tree = parse_tree_indirect(sha1);
  27         if (!tree)
  28                 return -1;
  29         trees[nr_trees++] = tree;
  30         return 0;
  31 }
  32
  33 static const char * const read_tree_usage[] = {
  34         "git read-tree [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u [--exclude-per-directory=<gitignore>] | -i]]  [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]]",
  35         NULL
  36 };
  37
  38 static int index_output_cb(const struct option *opt, const char *arg,
  39                                  int unset)
  40 {
  41         set_alternate_index_output(arg);
  42         return 0;
  43 }
  44
  45 static int exclude_per_directory_cb(const struct option *opt, const char *arg,
  46                                     int unset)
  47 {
  48         struct dir_struct *dir;
  49         struct unpack_trees_options *opts;
  50
  51         opts = (struct unpack_trees_options *)opt->value;
  52
  53         if (opts->dir)
  54                 die("more than one --exclude-per-directory given.");
  55
  56         dir = xcalloc(1, sizeof(*opts->dir));
  57         dir->flags |= DIR_SHOW_IGNORED;
  58         dir->exclude_per_dir = arg;
  59         opts->dir = dir;
  60         /* We do not need to nor want to do read-directory
  61          * here; we are merely interested in reusing the
  62          * per directory ignore stack mechanism.
  63          */
  64         return 0;
  65 }
  66
  67 static struct lock_file lock_file;
  68
  69 int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
  70 {
  71         int i, newfd, stage = 0;
  72         unsigned char sha1[20];
  73         struct tree_desc t[MAX_UNPACK_TREES];
  74         struct unpack_trees_options opts;
  75         int prefix_set = 0;
  76         const struct option read_tree_options[] = {
  77                 { OPTION_CALLBACK, 0, "index-output", NULL, "FILE",
  78                   "write resulting index to <FILE>",
  79                   PARSE_OPT_NONEG, index_output_cb },
  80                 OPT__VERBOSE(&opts.verbose_update),
  81                 OPT_GROUP("Merging"),
  82                 OPT_SET_INT('m', NULL, &opts.merge,
  83                             "perform a merge in addition to a read", 1),
  84                 OPT_SET_INT(0, "trivial", &opts.trivial_merges_only,
  85                             "3-way merge if no file level merging required", 1),
  86                 OPT_SET_INT(0, "aggressive", &opts.aggressive,
  87                             "3-way merge in presence of adds and removes", 1),
  88                 OPT_SET_INT(0, "reset", &opts.reset,
  89                             "same as -m, but discard unmerged entries", 1),
  90                 { OPTION_STRING, 0, "prefix", &opts.prefix, "<subdirectory>/",
  91                   "read the tree into the index under <subdirectory>/",
  92                   PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP },
  93                 OPT_SET_INT('u', NULL, &opts.update,
  94                             "update working tree with merge result", 1),
  95                 { OPTION_CALLBACK, 0, "exclude-per-directory", &opts,
  96                   "gitignore",
  97                   "allow explicitly ignored files to be overwritten",
  98                   PARSE_OPT_NONEG, exclude_per_directory_cb },
  99                 OPT_SET_INT('i', NULL, &opts.index_only,
 100                             "don't check the working tree after merging", 1),
 101                 OPT_END()
 102         };
 103
 104         memset(&opts, 0, sizeof(opts));
 105         opts.head_idx = -1;
 106         opts.src_index = &the_index;
 107         opts.dst_index = &the_index;
 108
 109         git_config(git_default_config, NULL);
 110
 111         argc = parse_options(argc, argv, unused_prefix, read_tree_options,
 112                              read_tree_usage, 0);
 113
 114         newfd = hold_locked_index(&lock_file, 1);
 115
 116         prefix_set = opts.prefix ? 1 : 0;
 117         if (1 < opts.merge + opts.reset + prefix_set)
 118                 die("Which one? -m, --reset, or --prefix?");
 119
 120         if (opts.reset || opts.merge || opts.prefix) {
 121                 if (read_cache_unmerged() && (opts.prefix || opts.merge))
 122                         die("You need to resolve your current index first");
 123                 stage = opts.merge = 1;
 124         }
 125
 126         for (i = 0; i < argc; i++) {
 127                 const char *arg = argv[i];
 128
 129                 if (get_sha1(arg, sha1))
 130                         die("Not a valid object name %s", arg);
 131                 if (list_tree(sha1) < 0)
 132                         die("failed to unpack tree object %s", arg);
 133                 stage++;
 134         }
 135         if (1 < opts.index_only + opts.update)
 136                 die("-u and -i at the same time makes no sense");
 137         if ((opts.update||opts.index_only) && !opts.merge)
 138                 die("%s is meaningless without -m, --reset, or --prefix",
 139                     opts.update ? "-u" : "-i");
 140         if ((opts.dir && !opts.update))
 141                 die("--exclude-per-directory is meaningless unless -u");
 142         if (opts.merge && !opts.index_only)
 143                 setup_work_tree();
 144
 145         if (opts.merge) {
 146                 if (stage < 2)
 147                         die("just how do you expect me to merge %d trees?", stage-1);
 148                 switch (stage - 1) {
 149                 case 1:
 150                         opts.fn = opts.prefix ? bind_merge : oneway_merge;
 151                         break;
 152                 case 2:
 153                         opts.fn = twoway_merge;
 154                         opts.initial_checkout = is_cache_unborn();
 155                         break;
 156                 case 3:
 157                 default:
 158                         opts.fn = threeway_merge;
 159                         break;
 160                 }
 161
 162                 if (stage - 1 >= 3)
 163                         opts.head_idx = stage - 2;
 164                 else
 165                         opts.head_idx = 1;
 166         }
 167
 168         cache_tree_free(&active_cache_tree);
 169         for (i = 0; i < nr_trees; i++) {
 170                 struct tree *tree = trees[i];
 171                 parse_tree(tree);
 172                 init_tree_desc(t+i, tree->buffer, tree->size);
 173         }
 174         if (unpack_trees(nr_trees, t, &opts))
 175                 return 128;
 176
 177         /*
 178          * When reading only one tree (either the most basic form,
 179          * "-m ent" or "--reset ent" form), we can obtain a fully
 180          * valid cache-tree because the index must match exactly
 181          * what came from the tree.
 182          *
 183          * The same holds true if we are switching between two trees
 184          * using read-tree -m A B.  The index must match B after that.
 185          */
 186         if (nr_trees == 1 && !opts.prefix)
 187                 prime_cache_tree(&active_cache_tree, trees[0]);
 188         else if (nr_trees == 2 && opts.merge)
 189                 prime_cache_tree(&active_cache_tree, trees[1]);
 190
 191         if (write_cache(newfd, active_cache, active_nr) ||
 192             commit_locked_index(&lock_file))
 193                 die("unable to write new index file");
 194         return 0;
 195 }