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 #include "resolve-undo.h"
  17
  18 static int nr_trees;
  19 static struct tree *trees[MAX_UNPACK_TREES];
  20
  21 static int list_tree(unsigned char *sha1)
  22 {
  23         struct tree *tree;
  24
  25         if (nr_trees >= MAX_UNPACK_TREES)
  26                 die("I cannot read more than %d trees", MAX_UNPACK_TREES);
  27         tree = parse_tree_indirect(sha1);
  28         if (!tree)
  29                 return -1;
  30         trees[nr_trees++] = tree;
  31         return 0;
  32 }
  33
  34 static const char * const read_tree_usage[] = {
  35         "git read-tree [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u [--exclude-per-directory=<gitignore>] | -i]]  [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]]",
  36         NULL
  37 };
  38
  39 static int index_output_cb(const struct option *opt, const char *arg,
  40                                  int unset)
  41 {
  42         set_alternate_index_output(arg);
  43         return 0;
  44 }
  45
  46 static int exclude_per_directory_cb(const struct option *opt, const char *arg,
  47                                     int unset)
  48 {
  49         struct dir_struct *dir;
  50         struct unpack_trees_options *opts;
  51
  52         opts = (struct unpack_trees_options *)opt->value;
  53
  54         if (opts->dir)
  55                 die("more than one --exclude-per-directory given.");
  56
  57         dir = xcalloc(1, sizeof(*opts->dir));
  58         dir->flags |= DIR_SHOW_IGNORED;
  59         dir->exclude_per_dir = arg;
  60         opts->dir = dir;
  61         /* We do not need to nor want to do read-directory
  62          * here; we are merely interested in reusing the
  63          * per directory ignore stack mechanism.
  64          */
  65         return 0;
  66 }
  67
  68 static struct lock_file lock_file;
  69
  70 int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
  71 {
  72         int i, newfd, stage = 0;
  73         unsigned char sha1[20];
  74         struct tree_desc t[MAX_UNPACK_TREES];
  75         struct unpack_trees_options opts;
  76         int prefix_set = 0;
  77         const struct option read_tree_options[] = {
  78                 { OPTION_CALLBACK, 0, "index-output", NULL, "FILE",
  79                   "write resulting index to <FILE>",
  80                   PARSE_OPT_NONEG, index_output_cb },
  81                 OPT__VERBOSE(&opts.verbose_update),
  82                 OPT_GROUP("Merging"),
  83                 OPT_SET_INT('m', NULL, &opts.merge,
  84                             "perform a merge in addition to a read", 1),
  85                 OPT_SET_INT(0, "trivial", &opts.trivial_merges_only,
  86                             "3-way merge if no file level merging required", 1),
  87                 OPT_SET_INT(0, "aggressive", &opts.aggressive,
  88                             "3-way merge in presence of adds and removes", 1),
  89                 OPT_SET_INT(0, "reset", &opts.reset,
  90                             "same as -m, but discard unmerged entries", 1),
  91                 { OPTION_STRING, 0, "prefix", &opts.prefix, "<subdirectory>/",
  92                   "read the tree into the index under <subdirectory>/",
  93                   PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP },
  94                 OPT_SET_INT('u', NULL, &opts.update,
  95                             "update working tree with merge result", 1),
  96                 { OPTION_CALLBACK, 0, "exclude-per-directory", &opts,
  97                   "gitignore",
  98                   "allow explicitly ignored files to be overwritten",
  99                   PARSE_OPT_NONEG, exclude_per_directory_cb },
 100                 OPT_SET_INT('i', NULL, &opts.index_only,
 101                             "don't check the working tree after merging", 1),
 102                 OPT_END()
 103         };
 104
 105         memset(&opts, 0, sizeof(opts));
 106         opts.head_idx = -1;
 107         opts.src_index = &the_index;
 108         opts.dst_index = &the_index;
 109
 110         git_config(git_default_config, NULL);
 111
 112         argc = parse_options(argc, argv, unused_prefix, read_tree_options,
 113                              read_tree_usage, 0);
 114
 115         newfd = hold_locked_index(&lock_file, 1);
 116
 117         prefix_set = opts.prefix ? 1 : 0;
 118         if (1 < opts.merge + opts.reset + prefix_set)
 119                 die("Which one? -m, --reset, or --prefix?");
 120
 121         if (opts.reset || opts.merge || opts.prefix) {
 122                 if (read_cache_unmerged() && (opts.prefix || opts.merge))
 123                         die("You need to resolve your current index first");
 124                 stage = opts.merge = 1;
 125         }
 126         resolve_undo_clear();
 127
 128         for (i = 0; i < argc; i++) {
 129                 const char *arg = argv[i];
 130
 131                 if (get_sha1(arg, sha1))
 132                         die("Not a valid object name %s", arg);
 133                 if (list_tree(sha1) < 0)
 134                         die("failed to unpack tree object %s", arg);
 135                 stage++;
 136         }
 137         if (1 < opts.index_only + opts.update)
 138                 die("-u and -i at the same time makes no sense");
 139         if ((opts.update||opts.index_only) && !opts.merge)
 140                 die("%s is meaningless without -m, --reset, or --prefix",
 141                     opts.update ? "-u" : "-i");
 142         if ((opts.dir && !opts.update))
 143                 die("--exclude-per-directory is meaningless unless -u");
 144         if (opts.merge && !opts.index_only)
 145                 setup_work_tree();
 146
 147         if (opts.merge) {
 148                 if (stage < 2)
 149                         die("just how do you expect me to merge %d trees?", stage-1);
 150                 switch (stage - 1) {
 151                 case 1:
 152                         opts.fn = opts.prefix ? bind_merge : oneway_merge;
 153                         break;
 154                 case 2:
 155                         opts.fn = twoway_merge;
 156                         opts.initial_checkout = is_cache_unborn();
 157                         break;
 158                 case 3:
 159                 default:
 160                         opts.fn = threeway_merge;
 161                         break;
 162                 }
 163
 164                 if (stage - 1 >= 3)
 165                         opts.head_idx = stage - 2;
 166                 else
 167                         opts.head_idx = 1;
 168         }
 169
 170         cache_tree_free(&active_cache_tree);
 171         for (i = 0; i < nr_trees; i++) {
 172                 struct tree *tree = trees[i];
 173                 parse_tree(tree);
 174                 init_tree_desc(t+i, tree->buffer, tree->size);
 175         }
 176         if (unpack_trees(nr_trees, t, &opts))
 177                 return 128;
 178
 179         /*
 180          * When reading only one tree (either the most basic form,
 181          * "-m ent" or "--reset ent" form), we can obtain a fully
 182          * valid cache-tree because the index must match exactly
 183          * what came from the tree.
 184          *
 185          * The same holds true if we are switching between two trees
 186          * using read-tree -m A B.  The index must match B after that.
 187          */
 188         if (nr_trees == 1 && !opts.prefix)
 189                 prime_cache_tree(&active_cache_tree, trees[0]);
 190         else if (nr_trees == 2 && opts.merge)
 191                 prime_cache_tree(&active_cache_tree, trees[1]);
 192
 193         if (write_cache(newfd, active_cache, active_nr) ||
 194             commit_locked_index(&lock_file))
 195                 die("unable to write new index file");
 196         return 0;
 197 }