No diff -b/-w output for all-whitespace changes
[gitweb.git] / builtin-read-tree.c
index 6bc042f852cb56739810d1f66e4295d805b5aeca..14c836b1693317d5d834606e5613d7ceacb3189c 100644 (file)
  *
  * Copyright (C) Linus Torvalds, 2005
  */
-#define DBRT_DEBUG 1
 
 #include "cache.h"
-
 #include "object.h"
 #include "tree.h"
 #include "tree-walk.h"
 #include "cache-tree.h"
 #include "unpack-trees.h"
+#include "dir.h"
 #include "builtin.h"
+#include "parse-options.h"
 
-static struct object_list *trees = NULL;
-
-static void reject_merge(struct cache_entry *ce)
-{
-       die("Entry '%s' would be overwritten by merge. Cannot merge.",
-           ce->name);
-}
+static int nr_trees;
+static struct tree *trees[MAX_UNPACK_TREES];
 
 static int list_tree(unsigned char *sha1)
 {
-       struct tree *tree = parse_tree_indirect(sha1);
+       struct tree *tree;
+
+       if (nr_trees >= MAX_UNPACK_TREES)
+               die("I cannot read more than %d trees", MAX_UNPACK_TREES);
+       tree = parse_tree_indirect(sha1);
        if (!tree)
                return -1;
-       object_list_append(&tree->object, &trees);
+       trees[nr_trees++] = tree;
        return 0;
 }
 
-static int same(struct cache_entry *a, struct cache_entry *b)
-{
-       if (!!a != !!b)
-               return 0;
-       if (!a && !b)
-               return 1;
-       return a->ce_mode == b->ce_mode && 
-               !memcmp(a->sha1, b->sha1, 20);
-}
-
+static const char * const read_tree_usage[] = {
+       "git read-tree [[-m [--trivial] [--aggressive] | --reset | --prefix=<prefix>] [-u [--exclude-per-directory=<gitignore>] | -i]]  [--index-output=<file>] <tree-ish1> [<tree-ish2> [<tree-ish3>]]",
+       NULL
+};
 
-/*
- * When a CE gets turned into an unmerged entry, we
- * want it to be up-to-date
- */
-static void verify_uptodate(struct cache_entry *ce,
-               struct unpack_trees_options *o)
+static int index_output_cb(const struct option *opt, const char *arg,
+                                int unset)
 {
-       struct stat st;
-
-       if (o->index_only || o->reset)
-               return;
-
-       if (!lstat(ce->name, &st)) {
-               unsigned changed = ce_match_stat(ce, &st, 1);
-               if (!changed)
-                       return;
-               errno = 0;
-       }
-       if (o->reset) {
-               ce->ce_flags |= htons(CE_UPDATE);
-               return;
-       }
-       if (errno == ENOENT)
-               return;
-       die("Entry '%s' not uptodate. Cannot merge.", ce->name);
-}
-
-static void invalidate_ce_path(struct cache_entry *ce)
-{
-       if (ce)
-               cache_tree_invalidate_path(active_cache_tree, ce->name);
-}
-
-/*
- * We do not want to remove or overwrite a working tree file that
- * is not tracked.
- */
-static void verify_absent(const char *path, const char *action,
-               struct unpack_trees_options *o)
-{
-       struct stat st;
-
-       if (o->index_only || o->reset || !o->update)
-               return;
-       if (!lstat(path, &st))
-               die("Untracked working tree file '%s' "
-                   "would be %s by merge.", path, action);
-}
-
-static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
-               struct unpack_trees_options *o)
-{
-       merge->ce_flags |= htons(CE_UPDATE);
-       if (old) {
-               /*
-                * See if we can re-use the old CE directly?
-                * That way we get the uptodate stat info.
-                *
-                * This also removes the UPDATE flag on
-                * a match.
-                */
-               if (same(old, merge)) {
-                       *merge = *old;
-               } else {
-                       verify_uptodate(old, o);
-                       invalidate_ce_path(old);
-               }
-       }
-       else {
-               verify_absent(merge->name, "overwritten", o);
-               invalidate_ce_path(merge);
-       }
-
-       merge->ce_flags &= ~htons(CE_STAGEMASK);
-       add_cache_entry(merge, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
-       return 1;
-}
-
-static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
-               struct unpack_trees_options *o)
-{
-       if (old)
-               verify_uptodate(old, o);
-       else
-               verify_absent(ce->name, "removed", o);
-       ce->ce_mode = 0;
-       add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE);
-       invalidate_ce_path(ce);
-       return 1;
-}
-
-static int keep_entry(struct cache_entry *ce)
-{
-       add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
-       return 1;
-}
-
-#if DBRT_DEBUG
-static void show_stage_entry(FILE *o,
-                            const char *label, const struct cache_entry *ce)
-{
-       if (!ce)
-               fprintf(o, "%s (missing)\n", label);
-       else
-               fprintf(o, "%s%06o %s %d\t%s\n",
-                       label,
-                       ntohl(ce->ce_mode),
-                       sha1_to_hex(ce->sha1),
-                       ce_stage(ce),
-                       ce->name);
+       set_alternate_index_output(arg);
+       return 0;
 }
-#endif
 
-static int threeway_merge(struct cache_entry **stages,
-               struct unpack_trees_options *o)
+static int exclude_per_directory_cb(const struct option *opt, const char *arg,
+                                   int unset)
 {
-       struct cache_entry *index;
-       struct cache_entry *head;
-       struct cache_entry *remote = stages[o->head_idx + 1];
-       int count;
-       int head_match = 0;
-       int remote_match = 0;
-       const char *path = NULL;
-
-       int df_conflict_head = 0;
-       int df_conflict_remote = 0;
-
-       int any_anc_missing = 0;
-       int no_anc_exists = 1;
-       int i;
-
-       for (i = 1; i < o->head_idx; i++) {
-               if (!stages[i])
-                       any_anc_missing = 1;
-               else {
-                       if (!path)
-                               path = stages[i]->name;
-                       no_anc_exists = 0;
-               }
-       }
-
-       index = stages[0];
-       head = stages[o->head_idx];
-
-       if (head == &o->df_conflict_entry) {
-               df_conflict_head = 1;
-               head = NULL;
-       }
-
-       if (remote == &o->df_conflict_entry) {
-               df_conflict_remote = 1;
-               remote = NULL;
-       }
-
-       if (!path && index)
-               path = index->name;
-       if (!path && head)
-               path = head->name;
-       if (!path && remote)
-               path = remote->name;
-
-       /* First, if there's a #16 situation, note that to prevent #13
-        * and #14.
-        */
-       if (!same(remote, head)) {
-               for (i = 1; i < o->head_idx; i++) {
-                       if (same(stages[i], head)) {
-                               head_match = i;
-                       }
-                       if (same(stages[i], remote)) {
-                               remote_match = i;
-                       }
-               }
-       }
+       struct dir_struct *dir;
+       struct unpack_trees_options *opts;
 
-       /* We start with cases where the index is allowed to match
-        * something other than the head: #14(ALT) and #2ALT, where it
-        * is permitted to match the result instead.
-        */
-       /* #14, #14ALT, #2ALT */
-       if (remote && !df_conflict_head && head_match && !remote_match) {
-               if (index && !same(index, remote) && !same(index, head))
-                       reject_merge(index);
-               return merged_entry(remote, index, o);
-       }
-       /*
-        * If we have an entry in the index cache, then we want to
-        * make sure that it matches head.
-        */
-       if (index && !same(index, head)) {
-               reject_merge(index);
-       }
-
-       if (head) {
-               /* #5ALT, #15 */
-               if (same(head, remote))
-                       return merged_entry(head, index, o);
-               /* #13, #3ALT */
-               if (!df_conflict_remote && remote_match && !head_match)
-                       return merged_entry(head, index, o);
-       }
-
-       /* #1 */
-       if (!head && !remote && any_anc_missing)
-               return 0;
-
-       /* Under the new "aggressive" rule, we resolve mostly trivial
-        * cases that we historically had git-merge-one-file resolve.
-        */
-       if (o->aggressive) {
-               int head_deleted = !head && !df_conflict_head;
-               int remote_deleted = !remote && !df_conflict_remote;
-               /*
-                * Deleted in both.
-                * Deleted in one and unchanged in the other.
-                */
-               if ((head_deleted && remote_deleted) ||
-                   (head_deleted && remote && remote_match) ||
-                   (remote_deleted && head && head_match)) {
-                       if (index)
-                               return deleted_entry(index, index, o);
-                       else if (path)
-                               verify_absent(path, "removed", o);
-                       return 0;
-               }
-               /*
-                * Added in both, identically.
-                */
-               if (no_anc_exists && head && remote && same(head, remote))
-                       return merged_entry(head, index, o);
+       opts = (struct unpack_trees_options *)opt->value;
 
-       }
+       if (opts->dir)
+               die("more than one --exclude-per-directory given.");
 
-       /* Below are "no merge" cases, which require that the index be
-        * up-to-date to avoid the files getting overwritten with
-        * conflict resolution files.
+       dir = xcalloc(1, sizeof(*opts->dir));
+       dir->flags |= DIR_SHOW_IGNORED;
+       dir->exclude_per_dir = arg;
+       opts->dir = dir;
+       /* We do not need to nor want to do read-directory
+        * here; we are merely interested in reusing the
+        * per directory ignore stack mechanism.
         */
-       if (index) {
-               verify_uptodate(index, o);
-       }
-       else if (path)
-               verify_absent(path, "overwritten", o);
-
-       o->nontrivial_merge = 1;
-
-       /* #2, #3, #4, #6, #7, #9, #11. */
-       count = 0;
-       if (!head_match || !remote_match) {
-               for (i = 1; i < o->head_idx; i++) {
-                       if (stages[i]) {
-                               keep_entry(stages[i]);
-                               count++;
-                               break;
-                       }
-               }
-       }
-#if DBRT_DEBUG
-       else {
-               fprintf(stderr, "read-tree: warning #16 detected\n");
-               show_stage_entry(stderr, "head   ", stages[head_match]);
-               show_stage_entry(stderr, "remote ", stages[remote_match]);
-       }
-#endif
-       if (head) { count += keep_entry(head); }
-       if (remote) { count += keep_entry(remote); }
-       return count;
-}
-
-/*
- * Two-way merge.
- *
- * The rule is to "carry forward" what is in the index without losing
- * information across a "fast forward", favoring a successful merge
- * over a merge failure when it makes sense.  For details of the
- * "carry forward" rule, please see <Documentation/git-read-tree.txt>.
- *
- */
-static int twoway_merge(struct cache_entry **src,
-               struct unpack_trees_options *o)
-{
-       struct cache_entry *current = src[0];
-       struct cache_entry *oldtree = src[1], *newtree = src[2];
-
-       if (o->merge_size != 2)
-               return error("Cannot do a twoway merge of %d trees",
-                            o->merge_size);
-
-       if (current) {
-               if ((!oldtree && !newtree) || /* 4 and 5 */
-                   (!oldtree && newtree &&
-                    same(current, newtree)) || /* 6 and 7 */
-                   (oldtree && newtree &&
-                    same(oldtree, newtree)) || /* 14 and 15 */
-                   (oldtree && newtree &&
-                    !same(oldtree, newtree) && /* 18 and 19*/
-                    same(current, newtree))) {
-                       return keep_entry(current);
-               }
-               else if (oldtree && !newtree && same(current, oldtree)) {
-                       /* 10 or 11 */
-                       return deleted_entry(oldtree, current, o);
-               }
-               else if (oldtree && newtree &&
-                        same(current, oldtree) && !same(current, newtree)) {
-                       /* 20 or 21 */
-                       return merged_entry(newtree, current, o);
-               }
-               else {
-                       /* all other failures */
-                       if (oldtree)
-                               reject_merge(oldtree);
-                       if (current)
-                               reject_merge(current);
-                       if (newtree)
-                               reject_merge(newtree);
-                       return -1;
-               }
-       }
-       else if (newtree)
-               return merged_entry(newtree, current, o);
-       else
-               return deleted_entry(oldtree, current, o);
-}
-
-/*
- * Bind merge.
- *
- * Keep the index entries at stage0, collapse stage1 but make sure
- * stage0 does not have anything there.
- */
-static int bind_merge(struct cache_entry **src,
-               struct unpack_trees_options *o)
-{
-       struct cache_entry *old = src[0];
-       struct cache_entry *a = src[1];
-
-       if (o->merge_size != 1)
-               return error("Cannot do a bind merge of %d trees\n",
-                            o->merge_size);
-       if (a && old)
-               die("Entry '%s' overlaps.  Cannot bind.", a->name);
-       if (!a)
-               return keep_entry(old);
-       else
-               return merged_entry(a, NULL, o);
-}
-
-/*
- * One-way merge.
- *
- * The rule is:
- * - take the stat information from stage0, take the data from stage1
- */
-static int oneway_merge(struct cache_entry **src,
-               struct unpack_trees_options *o)
-{
-       struct cache_entry *old = src[0];
-       struct cache_entry *a = src[1];
-
-       if (o->merge_size != 1)
-               return error("Cannot do a oneway merge of %d trees",
-                            o->merge_size);
-
-       if (!a)
-               return deleted_entry(old, old, o);
-       if (old && same(old, a)) {
-               if (o->reset) {
-                       struct stat st;
-                       if (lstat(old->name, &st) ||
-                           ce_match_stat(old, &st, 1))
-                               old->ce_flags |= htons(CE_UPDATE);
-               }
-               return keep_entry(old);
-       }
-       return merged_entry(a, old, o);
-}
-
-static int read_cache_unmerged(void)
-{
-       int i;
-       struct cache_entry **dst;
-       struct cache_entry *last = NULL;
-
-       read_cache();
-       dst = active_cache;
-       for (i = 0; i < active_nr; i++) {
-               struct cache_entry *ce = active_cache[i];
-               if (ce_stage(ce)) {
-                       if (last && !strcmp(ce->name, last->name))
-                               continue;
-                       invalidate_ce_path(ce);
-                       last = ce;
-                       ce->ce_mode = 0;
-                       ce->ce_flags &= ~htons(CE_STAGEMASK);
-               }
-               *dst++ = ce;
-       }
-       active_nr = dst - active_cache;
-       return !!last;
-}
-
-static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
-{
-       struct tree_desc desc;
-       struct name_entry entry;
-       int cnt;
-
-       memcpy(it->sha1, tree->object.sha1, 20);
-       desc.buf = tree->buffer;
-       desc.size = tree->size;
-       cnt = 0;
-       while (tree_entry(&desc, &entry)) {
-               if (!S_ISDIR(entry.mode))
-                       cnt++;
-               else {
-                       struct cache_tree_sub *sub;
-                       struct tree *subtree = lookup_tree(entry.sha1);
-                       if (!subtree->object.parsed)
-                               parse_tree(subtree);
-                       sub = cache_tree_sub(it, entry.path);
-                       sub->cache_tree = cache_tree();
-                       prime_cache_tree_rec(sub->cache_tree, subtree);
-                       cnt += sub->cache_tree->entry_count;
-               }
-       }
-       it->entry_count = cnt;
-}
-
-static void prime_cache_tree(void)
-{
-       struct tree *tree = (struct tree *)trees->item;
-       if (!tree)
-               return;
-       active_cache_tree = cache_tree();
-       prime_cache_tree_rec(active_cache_tree, tree);
-
+       return 0;
 }
 
-static const char read_tree_usage[] = "git-read-tree (<sha> | [[-m [--aggressive] | --reset | --prefix=<prefix>] [-u | -i]] <sha1> [<sha2> [<sha3>]])";
-
 static struct lock_file lock_file;
 
-int cmd_read_tree(int argc, const char **argv, const char *prefix)
+int cmd_read_tree(int argc, const char **argv, const char *unused_prefix)
 {
        int i, newfd, stage = 0;
        unsigned char sha1[20];
+       struct tree_desc t[MAX_UNPACK_TREES];
        struct unpack_trees_options opts;
+       int prefix_set = 0;
+       const struct option read_tree_options[] = {
+               { OPTION_CALLBACK, 0, "index-output", NULL, "FILE",
+                 "write resulting index to <FILE>",
+                 PARSE_OPT_NONEG, index_output_cb },
+               OPT__VERBOSE(&opts.verbose_update),
+               OPT_GROUP("Merging"),
+               OPT_SET_INT('m', NULL, &opts.merge,
+                           "perform a merge in addition to a read", 1),
+               OPT_SET_INT(0, "trivial", &opts.trivial_merges_only,
+                           "3-way merge if no file level merging required", 1),
+               OPT_SET_INT(0, "aggressive", &opts.aggressive,
+                           "3-way merge in presence of adds and removes", 1),
+               OPT_SET_INT(0, "reset", &opts.reset,
+                           "same as -m, but discard unmerged entries", 1),
+               { OPTION_STRING, 0, "prefix", &opts.prefix, "<subdirectory>/",
+                 "read the tree into the index under <subdirectory>/",
+                 PARSE_OPT_NONEG | PARSE_OPT_LITERAL_ARGHELP },
+               OPT_SET_INT('u', NULL, &opts.update,
+                           "update working tree with merge result", 1),
+               { OPTION_CALLBACK, 0, "exclude-per-directory", &opts,
+                 "gitignore",
+                 "allow explicitly ignored files to be overwritten",
+                 PARSE_OPT_NONEG, exclude_per_directory_cb },
+               OPT_SET_INT('i', NULL, &opts.index_only,
+                           "don't check the working tree after merging", 1),
+               OPT_END()
+       };
 
        memset(&opts, 0, sizeof(opts));
        opts.head_idx = -1;
+       opts.src_index = &the_index;
+       opts.dst_index = &the_index;
 
-       setup_git_directory();
-       git_config(git_default_config);
-
-       newfd = hold_lock_file_for_update(&lock_file, get_index_file());
-       if (newfd < 0)
-               die("unable to create new index file");
-
-       git_config(git_default_config);
-
-       for (i = 1; i < argc; i++) {
-               const char *arg = argv[i];
-
-               /* "-u" means "update", meaning that a merge will update
-                * the working tree.
-                */
-               if (!strcmp(arg, "-u")) {
-                       opts.update = 1;
-                       continue;
-               }
+       git_config(git_default_config, NULL);
 
-               if (!strcmp(arg, "-v")) {
-                       opts.verbose_update = 1;
-                       continue;
-               }
-
-               /* "-i" means "index only", meaning that a merge will
-                * not even look at the working tree.
-                */
-               if (!strcmp(arg, "-i")) {
-                       opts.index_only = 1;
-                       continue;
-               }
-
-               /* "--prefix=<subdirectory>/" means keep the current index
-                *  entries and put the entries from the tree under the
-                * given subdirectory.
-                */
-               if (!strncmp(arg, "--prefix=", 9)) {
-                       if (stage || opts.merge || opts.prefix)
-                               usage(read_tree_usage);
-                       opts.prefix = arg + 9;
-                       opts.merge = 1;
-                       stage = 1;
-                       if (read_cache_unmerged())
-                               die("you need to resolve your current index first");
-                       continue;
-               }
-
-               /* This differs from "-m" in that we'll silently ignore
-                * unmerged entries and overwrite working tree files that
-                * correspond to them.
-                */
-               if (!strcmp(arg, "--reset")) {
-                       if (stage || opts.merge || opts.prefix)
-                               usage(read_tree_usage);
-                       opts.reset = 1;
-                       opts.merge = 1;
-                       stage = 1;
-                       read_cache_unmerged();
-                       continue;
-               }
+       newfd = hold_locked_index(&lock_file, 1);
 
-               if (!strcmp(arg, "--trivial")) {
-                       opts.trivial_merges_only = 1;
-                       continue;
-               }
+       argc = parse_options(argc, argv, unused_prefix, read_tree_options,
+                            read_tree_usage, 0);
 
-               if (!strcmp(arg, "--aggressive")) {
-                       opts.aggressive = 1;
-                       continue;
-               }
+       prefix_set = opts.prefix ? 1 : 0;
+       if (1 < opts.merge + opts.reset + prefix_set)
+               die("Which one? -m, --reset, or --prefix?");
 
-               /* "-m" stands for "merge", meaning we start in stage 1 */
-               if (!strcmp(arg, "-m")) {
-                       if (stage || opts.merge || opts.prefix)
-                               usage(read_tree_usage);
-                       if (read_cache_unmerged())
-                               die("you need to resolve your current index first");
-                       stage = 1;
-                       opts.merge = 1;
-                       continue;
-               }
+       if (opts.reset || opts.merge || opts.prefix) {
+               if (read_cache_unmerged() && (opts.prefix || opts.merge))
+                       die("You need to resolve your current index first");
+               stage = opts.merge = 1;
+       }
 
-               /* using -u and -i at the same time makes no sense */
-               if (1 < opts.index_only + opts.update)
-                       usage(read_tree_usage);
+       for (i = 0; i < argc; i++) {
+               const char *arg = argv[i];
 
                if (get_sha1(arg, sha1))
                        die("Not a valid object name %s", arg);
@@ -586,28 +132,15 @@ int cmd_read_tree(int argc, const char **argv, const char *prefix)
                        die("failed to unpack tree object %s", arg);
                stage++;
        }
+       if (1 < opts.index_only + opts.update)
+               die("-u and -i at the same time makes no sense");
        if ((opts.update||opts.index_only) && !opts.merge)
-               usage(read_tree_usage);
-
-       if (opts.prefix) {
-               int pfxlen = strlen(opts.prefix);
-               int pos;
-               if (opts.prefix[pfxlen-1] != '/')
-                       die("prefix must end with /");
-               if (stage != 2)
-                       die("binding merge takes only one tree");
-               pos = cache_name_pos(opts.prefix, pfxlen);
-               if (0 <= pos)
-                       die("corrupt index file");
-               pos = -pos-1;
-               if (pos < active_nr &&
-                   !strncmp(active_cache[pos]->name, opts.prefix, pfxlen))
-                       die("subdirectory '%s' already exists.", opts.prefix);
-               pos = cache_name_pos(opts.prefix, pfxlen-1);
-               if (0 <= pos)
-                       die("file '%.*s' already exists.",
-                                       pfxlen-1, opts.prefix);
-       }
+               die("%s is meaningless without -m, --reset, or --prefix",
+                   opts.update ? "-u" : "-i");
+       if ((opts.dir && !opts.update))
+               die("--exclude-per-directory is meaningless unless -u");
+       if (opts.merge && !opts.index_only)
+               setup_work_tree();
 
        if (opts.merge) {
                if (stage < 2)
@@ -618,11 +151,11 @@ int cmd_read_tree(int argc, const char **argv, const char *prefix)
                        break;
                case 2:
                        opts.fn = twoway_merge;
+                       opts.initial_checkout = is_cache_unborn();
                        break;
                case 3:
                default:
                        opts.fn = threeway_merge;
-                       cache_tree_free(&active_cache_tree);
                        break;
                }
 
@@ -632,21 +165,31 @@ int cmd_read_tree(int argc, const char **argv, const char *prefix)
                        opts.head_idx = 1;
        }
 
-       unpack_trees(trees, &opts);
+       cache_tree_free(&active_cache_tree);
+       for (i = 0; i < nr_trees; i++) {
+               struct tree *tree = trees[i];
+               parse_tree(tree);
+               init_tree_desc(t+i, tree->buffer, tree->size);
+       }
+       if (unpack_trees(nr_trees, t, &opts))
+               return 128;
 
        /*
         * When reading only one tree (either the most basic form,
         * "-m ent" or "--reset ent" form), we can obtain a fully
         * valid cache-tree because the index must match exactly
         * what came from the tree.
+        *
+        * The same holds true if we are switching between two trees
+        * using read-tree -m A B.  The index must match B after that.
         */
-       if (trees && trees->item && !opts.prefix && (!opts.merge || (stage == 2))) {
-               cache_tree_free(&active_cache_tree);
-               prime_cache_tree();
-       }
+       if (nr_trees == 1 && !opts.prefix)
+               prime_cache_tree(&active_cache_tree, trees[0]);
+       else if (nr_trees == 2 && opts.merge)
+               prime_cache_tree(&active_cache_tree, trees[1]);
 
        if (write_cache(newfd, active_cache, active_nr) ||
-           close(newfd) || commit_lock_file(&lock_file))
+           commit_locked_index(&lock_file))
                die("unable to write new index file");
        return 0;
 }