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-rw-r--r--builtin-read-tree.c1045
1 files changed, 1045 insertions, 0 deletions
diff --git a/builtin-read-tree.c b/builtin-read-tree.c
new file mode 100644
index 0000000..04506da
--- /dev/null
+++ b/builtin-read-tree.c
@@ -0,0 +1,1045 @@
+/*
+ * GIT - The information manager from hell
+ *
+ * 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 <sys/time.h>
+#include <signal.h>
+#include "builtin.h"
+
+static int reset = 0;
+static int merge = 0;
+static int update = 0;
+static int index_only = 0;
+static int nontrivial_merge = 0;
+static int trivial_merges_only = 0;
+static int aggressive = 0;
+static int verbose_update = 0;
+static volatile int progress_update = 0;
+static const char *prefix = NULL;
+
+static int head_idx = -1;
+static int merge_size = 0;
+
+static struct object_list *trees = NULL;
+
+static struct cache_entry df_conflict_entry = {
+};
+
+struct tree_entry_list {
+ struct tree_entry_list *next;
+ unsigned directory : 1;
+ unsigned executable : 1;
+ unsigned symlink : 1;
+ unsigned int mode;
+ const char *name;
+ const unsigned char *sha1;
+};
+
+static struct tree_entry_list df_conflict_list = {
+ .name = NULL,
+ .next = &df_conflict_list
+};
+
+typedef int (*merge_fn_t)(struct cache_entry **src);
+
+static struct tree_entry_list *create_tree_entry_list(struct tree *tree)
+{
+ struct tree_desc desc;
+ struct name_entry one;
+ struct tree_entry_list *ret = NULL;
+ struct tree_entry_list **list_p = &ret;
+
+ desc.buf = tree->buffer;
+ desc.size = tree->size;
+
+ while (tree_entry(&desc, &one)) {
+ struct tree_entry_list *entry;
+
+ entry = xmalloc(sizeof(struct tree_entry_list));
+ entry->name = one.path;
+ entry->sha1 = one.sha1;
+ entry->mode = one.mode;
+ entry->directory = S_ISDIR(one.mode) != 0;
+ entry->executable = (one.mode & S_IXUSR) != 0;
+ entry->symlink = S_ISLNK(one.mode) != 0;
+ entry->next = NULL;
+
+ *list_p = entry;
+ list_p = &entry->next;
+ }
+ return ret;
+}
+
+static int entcmp(const char *name1, int dir1, const char *name2, int dir2)
+{
+ int len1 = strlen(name1);
+ int len2 = strlen(name2);
+ int len = len1 < len2 ? len1 : len2;
+ int ret = memcmp(name1, name2, len);
+ unsigned char c1, c2;
+ if (ret)
+ return ret;
+ c1 = name1[len];
+ c2 = name2[len];
+ if (!c1 && dir1)
+ c1 = '/';
+ if (!c2 && dir2)
+ c2 = '/';
+ ret = (c1 < c2) ? -1 : (c1 > c2) ? 1 : 0;
+ if (c1 && c2 && !ret)
+ ret = len1 - len2;
+ return ret;
+}
+
+static int unpack_trees_rec(struct tree_entry_list **posns, int len,
+ const char *base, merge_fn_t fn, int *indpos)
+{
+ int baselen = strlen(base);
+ int src_size = len + 1;
+ do {
+ int i;
+ const char *first;
+ int firstdir = 0;
+ int pathlen;
+ unsigned ce_size;
+ struct tree_entry_list **subposns;
+ struct cache_entry **src;
+ int any_files = 0;
+ int any_dirs = 0;
+ char *cache_name;
+ int ce_stage;
+
+ /* Find the first name in the input. */
+
+ first = NULL;
+ cache_name = NULL;
+
+ /* Check the cache */
+ if (merge && *indpos < active_nr) {
+ /* This is a bit tricky: */
+ /* If the index has a subdirectory (with
+ * contents) as the first name, it'll get a
+ * filename like "foo/bar". But that's after
+ * "foo", so the entry in trees will get
+ * handled first, at which point we'll go into
+ * "foo", and deal with "bar" from the index,
+ * because the base will be "foo/". The only
+ * way we can actually have "foo/bar" first of
+ * all the things is if the trees don't
+ * contain "foo" at all, in which case we'll
+ * handle "foo/bar" without going into the
+ * directory, but that's fine (and will return
+ * an error anyway, with the added unknown
+ * file case.
+ */
+
+ cache_name = active_cache[*indpos]->name;
+ if (strlen(cache_name) > baselen &&
+ !memcmp(cache_name, base, baselen)) {
+ cache_name += baselen;
+ first = cache_name;
+ } else {
+ cache_name = NULL;
+ }
+ }
+
+#if DBRT_DEBUG > 1
+ if (first)
+ printf("index %s\n", first);
+#endif
+ for (i = 0; i < len; i++) {
+ if (!posns[i] || posns[i] == &df_conflict_list)
+ continue;
+#if DBRT_DEBUG > 1
+ printf("%d %s\n", i + 1, posns[i]->name);
+#endif
+ if (!first || entcmp(first, firstdir,
+ posns[i]->name,
+ posns[i]->directory) > 0) {
+ first = posns[i]->name;
+ firstdir = posns[i]->directory;
+ }
+ }
+ /* No name means we're done */
+ if (!first)
+ return 0;
+
+ pathlen = strlen(first);
+ ce_size = cache_entry_size(baselen + pathlen);
+
+ src = xcalloc(src_size, sizeof(struct cache_entry *));
+
+ subposns = xcalloc(len, sizeof(struct tree_list_entry *));
+
+ if (cache_name && !strcmp(cache_name, first)) {
+ any_files = 1;
+ src[0] = active_cache[*indpos];
+ remove_cache_entry_at(*indpos);
+ }
+
+ for (i = 0; i < len; i++) {
+ struct cache_entry *ce;
+
+ if (!posns[i] ||
+ (posns[i] != &df_conflict_list &&
+ strcmp(first, posns[i]->name))) {
+ continue;
+ }
+
+ if (posns[i] == &df_conflict_list) {
+ src[i + merge] = &df_conflict_entry;
+ continue;
+ }
+
+ if (posns[i]->directory) {
+ struct tree *tree = lookup_tree(posns[i]->sha1);
+ any_dirs = 1;
+ parse_tree(tree);
+ subposns[i] = create_tree_entry_list(tree);
+ posns[i] = posns[i]->next;
+ src[i + merge] = &df_conflict_entry;
+ continue;
+ }
+
+ if (!merge)
+ ce_stage = 0;
+ else if (i + 1 < head_idx)
+ ce_stage = 1;
+ else if (i + 1 > head_idx)
+ ce_stage = 3;
+ else
+ ce_stage = 2;
+
+ ce = xcalloc(1, ce_size);
+ ce->ce_mode = create_ce_mode(posns[i]->mode);
+ ce->ce_flags = create_ce_flags(baselen + pathlen,
+ ce_stage);
+ memcpy(ce->name, base, baselen);
+ memcpy(ce->name + baselen, first, pathlen + 1);
+
+ any_files = 1;
+
+ memcpy(ce->sha1, posns[i]->sha1, 20);
+ src[i + merge] = ce;
+ subposns[i] = &df_conflict_list;
+ posns[i] = posns[i]->next;
+ }
+ if (any_files) {
+ if (merge) {
+ int ret;
+
+#if DBRT_DEBUG > 1
+ printf("%s:\n", first);
+ for (i = 0; i < src_size; i++) {
+ printf(" %d ", i);
+ if (src[i])
+ printf("%s\n", sha1_to_hex(src[i]->sha1));
+ else
+ printf("\n");
+ }
+#endif
+ ret = fn(src);
+
+#if DBRT_DEBUG > 1
+ printf("Added %d entries\n", ret);
+#endif
+ *indpos += ret;
+ } else {
+ for (i = 0; i < src_size; i++) {
+ if (src[i]) {
+ add_cache_entry(src[i], ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
+ }
+ }
+ }
+ }
+ if (any_dirs) {
+ char *newbase = xmalloc(baselen + 2 + pathlen);
+ memcpy(newbase, base, baselen);
+ memcpy(newbase + baselen, first, pathlen);
+ newbase[baselen + pathlen] = '/';
+ newbase[baselen + pathlen + 1] = '\0';
+ if (unpack_trees_rec(subposns, len, newbase, fn,
+ indpos))
+ return -1;
+ free(newbase);
+ }
+ free(subposns);
+ free(src);
+ } while (1);
+}
+
+static void reject_merge(struct cache_entry *ce)
+{
+ die("Entry '%s' would be overwritten by merge. Cannot merge.",
+ ce->name);
+}
+
+/* Unlink the last component and attempt to remove leading
+ * directories, in case this unlink is the removal of the
+ * last entry in the directory -- empty directories are removed.
+ */
+static void unlink_entry(char *name)
+{
+ char *cp, *prev;
+
+ if (unlink(name))
+ return;
+ prev = NULL;
+ while (1) {
+ int status;
+ cp = strrchr(name, '/');
+ if (prev)
+ *prev = '/';
+ if (!cp)
+ break;
+
+ *cp = 0;
+ status = rmdir(name);
+ if (status) {
+ *cp = '/';
+ break;
+ }
+ prev = cp;
+ }
+}
+
+static void progress_interval(int signum)
+{
+ progress_update = 1;
+}
+
+static void setup_progress_signal(void)
+{
+ struct sigaction sa;
+ struct itimerval v;
+
+ memset(&sa, 0, sizeof(sa));
+ sa.sa_handler = progress_interval;
+ sigemptyset(&sa.sa_mask);
+ sa.sa_flags = SA_RESTART;
+ sigaction(SIGALRM, &sa, NULL);
+
+ v.it_interval.tv_sec = 1;
+ v.it_interval.tv_usec = 0;
+ v.it_value = v.it_interval;
+ setitimer(ITIMER_REAL, &v, NULL);
+}
+
+static void check_updates(struct cache_entry **src, int nr)
+{
+ static struct checkout state = {
+ .base_dir = "",
+ .force = 1,
+ .quiet = 1,
+ .refresh_cache = 1,
+ };
+ unsigned short mask = htons(CE_UPDATE);
+ unsigned last_percent = 200, cnt = 0, total = 0;
+
+ if (update && verbose_update) {
+ for (total = cnt = 0; cnt < nr; cnt++) {
+ struct cache_entry *ce = src[cnt];
+ if (!ce->ce_mode || ce->ce_flags & mask)
+ total++;
+ }
+
+ /* Don't bother doing this for very small updates */
+ if (total < 250)
+ total = 0;
+
+ if (total) {
+ fprintf(stderr, "Checking files out...\n");
+ setup_progress_signal();
+ progress_update = 1;
+ }
+ cnt = 0;
+ }
+
+ while (nr--) {
+ struct cache_entry *ce = *src++;
+
+ if (total) {
+ if (!ce->ce_mode || ce->ce_flags & mask) {
+ unsigned percent;
+ cnt++;
+ percent = (cnt * 100) / total;
+ if (percent != last_percent ||
+ progress_update) {
+ fprintf(stderr, "%4u%% (%u/%u) done\r",
+ percent, cnt, total);
+ last_percent = percent;
+ progress_update = 0;
+ }
+ }
+ }
+ if (!ce->ce_mode) {
+ if (update)
+ unlink_entry(ce->name);
+ continue;
+ }
+ if (ce->ce_flags & mask) {
+ ce->ce_flags &= ~mask;
+ if (update)
+ checkout_entry(ce, &state, NULL);
+ }
+ }
+ if (total) {
+ signal(SIGALRM, SIG_IGN);
+ fputc('\n', stderr);
+ }
+}
+
+static int unpack_trees(merge_fn_t fn)
+{
+ int indpos = 0;
+ unsigned len = object_list_length(trees);
+ struct tree_entry_list **posns;
+ int i;
+ struct object_list *posn = trees;
+ merge_size = len;
+
+ if (len) {
+ posns = xmalloc(len * sizeof(struct tree_entry_list *));
+ for (i = 0; i < len; i++) {
+ posns[i] = create_tree_entry_list((struct tree *) posn->item);
+ posn = posn->next;
+ }
+ if (unpack_trees_rec(posns, len, prefix ? prefix : "",
+ fn, &indpos))
+ return -1;
+ }
+
+ if (trivial_merges_only && nontrivial_merge)
+ die("Merge requires file-level merging");
+
+ check_updates(active_cache, active_nr);
+ return 0;
+}
+
+static int list_tree(unsigned char *sha1)
+{
+ struct tree *tree = parse_tree_indirect(sha1);
+ if (!tree)
+ return -1;
+ object_list_append(&tree->object, &trees);
+ 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);
+}
+
+
+/*
+ * 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 stat st;
+
+ if (index_only || reset)
+ return;
+
+ if (!lstat(ce->name, &st)) {
+ unsigned changed = ce_match_stat(ce, &st, 1);
+ if (!changed)
+ return;
+ errno = 0;
+ }
+ if (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 stat st;
+
+ if (index_only || reset || !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)
+{
+ 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);
+ invalidate_ce_path(old);
+ }
+ }
+ else {
+ verify_absent(merge->name, "overwritten");
+ invalidate_ce_path(merge);
+ }
+
+ merge->ce_flags &= ~htons(CE_STAGEMASK);
+ add_cache_entry(merge, ADD_CACHE_OK_TO_ADD);
+ return 1;
+}
+
+static int deleted_entry(struct cache_entry *ce, struct cache_entry *old)
+{
+ if (old)
+ verify_uptodate(old);
+ else
+ verify_absent(ce->name, "removed");
+ ce->ce_mode = 0;
+ add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
+ 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);
+}
+#endif
+
+static int threeway_merge(struct cache_entry **stages)
+{
+ struct cache_entry *index;
+ struct cache_entry *head;
+ struct cache_entry *remote = stages[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 < 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[head_idx];
+
+ if (head == &df_conflict_entry) {
+ df_conflict_head = 1;
+ head = NULL;
+ }
+
+ if (remote == &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 < head_idx; i++) {
+ if (same(stages[i], head)) {
+ head_match = i;
+ }
+ if (same(stages[i], remote)) {
+ remote_match = i;
+ }
+ }
+ }
+
+ /* 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);
+ }
+ /*
+ * 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);
+ /* #13, #3ALT */
+ if (!df_conflict_remote && remote_match && !head_match)
+ return merged_entry(head, index);
+ }
+
+ /* #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 (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);
+ else if (path)
+ verify_absent(path, "removed");
+ return 0;
+ }
+ /*
+ * Added in both, identically.
+ */
+ if (no_anc_exists && head && remote && same(head, remote))
+ return merged_entry(head, index);
+
+ }
+
+ /* Below are "no merge" cases, which require that the index be
+ * up-to-date to avoid the files getting overwritten with
+ * conflict resolution files.
+ */
+ if (index) {
+ verify_uptodate(index);
+ }
+ else if (path)
+ verify_absent(path, "overwritten");
+
+ nontrivial_merge = 1;
+
+ /* #2, #3, #4, #6, #7, #9, #11. */
+ count = 0;
+ if (!head_match || !remote_match) {
+ for (i = 1; i < 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 cache_entry *current = src[0];
+ struct cache_entry *oldtree = src[1], *newtree = src[2];
+
+ if (merge_size != 2)
+ return error("Cannot do a twoway merge of %d trees",
+ 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);
+ }
+ else if (oldtree && newtree &&
+ same(current, oldtree) && !same(current, newtree)) {
+ /* 20 or 21 */
+ return merged_entry(newtree, current);
+ }
+ 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);
+ else
+ return deleted_entry(oldtree, current);
+}
+
+/*
+ * 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 cache_entry *old = src[0];
+ struct cache_entry *a = src[1];
+
+ if (merge_size != 1)
+ return error("Cannot do a bind merge of %d trees\n",
+ 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);
+}
+
+/*
+ * 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 cache_entry *old = src[0];
+ struct cache_entry *a = src[1];
+
+ if (merge_size != 1)
+ return error("Cannot do a oneway merge of %d trees",
+ merge_size);
+
+ if (!a)
+ return deleted_entry(old, old);
+ if (old && same(old, a)) {
+ if (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);
+}
+
+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);
+
+}
+
+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, char **envp)
+{
+ int i, newfd, stage = 0;
+ unsigned char sha1[20];
+ merge_fn_t fn = NULL;
+
+ 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);
+
+ merge = 0;
+ reset = 0;
+ 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")) {
+ update = 1;
+ continue;
+ }
+
+ if (!strcmp(arg, "-v")) {
+ verbose_update = 1;
+ continue;
+ }
+
+ /* "-i" means "index only", meaning that a merge will
+ * not even look at the working tree.
+ */
+ if (!strcmp(arg, "-i")) {
+ 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 || merge || prefix)
+ usage(read_tree_usage);
+ prefix = arg + 9;
+ 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 || merge || prefix)
+ usage(read_tree_usage);
+ reset = 1;
+ merge = 1;
+ stage = 1;
+ read_cache_unmerged();
+ continue;
+ }
+
+ if (!strcmp(arg, "--trivial")) {
+ trivial_merges_only = 1;
+ continue;
+ }
+
+ if (!strcmp(arg, "--aggressive")) {
+ aggressive = 1;
+ continue;
+ }
+
+ /* "-m" stands for "merge", meaning we start in stage 1 */
+ if (!strcmp(arg, "-m")) {
+ if (stage || merge || prefix)
+ usage(read_tree_usage);
+ if (read_cache_unmerged())
+ die("you need to resolve your current index first");
+ stage = 1;
+ merge = 1;
+ continue;
+ }
+
+ /* using -u and -i at the same time makes no sense */
+ if (1 < index_only + update)
+ usage(read_tree_usage);
+
+ if (get_sha1(arg, sha1))
+ die("Not a valid object name %s", arg);
+ if (list_tree(sha1) < 0)
+ die("failed to unpack tree object %s", arg);
+ stage++;
+ }
+ if ((update||index_only) && !merge)
+ usage(read_tree_usage);
+
+ if (prefix) {
+ int pfxlen = strlen(prefix);
+ int pos;
+ if (prefix[pfxlen-1] != '/')
+ die("prefix must end with /");
+ if (stage != 2)
+ die("binding merge takes only one tree");
+ pos = cache_name_pos(prefix, pfxlen);
+ if (0 <= pos)
+ die("corrupt index file");
+ pos = -pos-1;
+ if (pos < active_nr &&
+ !strncmp(active_cache[pos]->name, prefix, pfxlen))
+ die("subdirectory '%s' already exists.", prefix);
+ pos = cache_name_pos(prefix, pfxlen-1);
+ if (0 <= pos)
+ die("file '%.*s' already exists.", pfxlen-1, prefix);
+ }
+
+ if (merge) {
+ if (stage < 2)
+ die("just how do you expect me to merge %d trees?", stage-1);
+ switch (stage - 1) {
+ case 1:
+ fn = prefix ? bind_merge : oneway_merge;
+ break;
+ case 2:
+ fn = twoway_merge;
+ break;
+ case 3:
+ default:
+ fn = threeway_merge;
+ cache_tree_free(&active_cache_tree);
+ break;
+ }
+
+ if (stage - 1 >= 3)
+ head_idx = stage - 2;
+ else
+ head_idx = 1;
+ }
+
+ unpack_trees(fn);
+
+ /*
+ * 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.
+ */
+ if (trees && trees->item && !prefix && (!merge || (stage == 2))) {
+ cache_tree_free(&active_cache_tree);
+ prime_cache_tree();
+ }
+
+ if (write_cache(newfd, active_cache, active_nr) ||
+ commit_lock_file(&lock_file))
+ die("unable to write new index file");
+ return 0;
+}