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-rw-r--r--unpack-trees.c934
1 files changed, 934 insertions, 0 deletions
diff --git a/unpack-trees.c b/unpack-trees.c
new file mode 100644
index 0000000000..be89d52e8c
--- /dev/null
+++ b/unpack-trees.c
@@ -0,0 +1,934 @@
+#define NO_THE_INDEX_COMPATIBILITY_MACROS
+#include "cache.h"
+#include "dir.h"
+#include "tree.h"
+#include "tree-walk.h"
+#include "cache-tree.h"
+#include "unpack-trees.h"
+#include "progress.h"
+#include "refs.h"
+
+static void add_entry(struct unpack_trees_options *o, struct cache_entry *ce,
+ unsigned int set, unsigned int clear)
+{
+ unsigned int size = ce_size(ce);
+ struct cache_entry *new = xmalloc(size);
+
+ clear |= CE_HASHED | CE_UNHASHED;
+
+ memcpy(new, ce, size);
+ new->next = NULL;
+ new->ce_flags = (new->ce_flags & ~clear) | set;
+ add_index_entry(&o->result, new, ADD_CACHE_OK_TO_ADD|ADD_CACHE_OK_TO_REPLACE|ADD_CACHE_SKIP_DFCHECK);
+}
+
+/* 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 *last_symlink)
+{
+ char *cp, *prev;
+
+ if (has_symlink_leading_path(name, last_symlink))
+ return;
+ 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 struct checkout state;
+static void check_updates(struct unpack_trees_options *o)
+{
+ unsigned cnt = 0, total = 0;
+ struct progress *progress = NULL;
+ char last_symlink[PATH_MAX];
+ struct index_state *index = &o->result;
+ int i;
+
+ if (o->update && o->verbose_update) {
+ for (total = cnt = 0; cnt < index->cache_nr; cnt++) {
+ struct cache_entry *ce = index->cache[cnt];
+ if (ce->ce_flags & (CE_UPDATE | CE_REMOVE))
+ total++;
+ }
+
+ progress = start_progress_delay("Checking out files",
+ total, 50, 1);
+ cnt = 0;
+ }
+
+ *last_symlink = '\0';
+ for (i = 0; i < index->cache_nr; i++) {
+ struct cache_entry *ce = index->cache[i];
+
+ if (ce->ce_flags & (CE_UPDATE | CE_REMOVE))
+ display_progress(progress, ++cnt);
+ if (ce->ce_flags & CE_REMOVE) {
+ if (o->update)
+ unlink_entry(ce->name, last_symlink);
+ remove_index_entry_at(&o->result, i);
+ i--;
+ continue;
+ }
+ if (ce->ce_flags & CE_UPDATE) {
+ ce->ce_flags &= ~CE_UPDATE;
+ if (o->update) {
+ checkout_entry(ce, &state, NULL);
+ *last_symlink = '\0';
+ }
+ }
+ }
+ stop_progress(&progress);
+}
+
+static inline int call_unpack_fn(struct cache_entry **src, struct unpack_trees_options *o)
+{
+ int ret = o->fn(src, o);
+ if (ret > 0)
+ ret = 0;
+ return ret;
+}
+
+static int unpack_index_entry(struct cache_entry *ce, struct unpack_trees_options *o)
+{
+ struct cache_entry *src[5] = { ce, };
+
+ o->pos++;
+ if (ce_stage(ce)) {
+ if (o->skip_unmerged) {
+ add_entry(o, ce, 0, 0);
+ return 0;
+ }
+ }
+ return call_unpack_fn(src, o);
+}
+
+int traverse_trees_recursive(int n, unsigned long dirmask, unsigned long df_conflicts, struct name_entry *names, struct traverse_info *info)
+{
+ int i;
+ struct tree_desc t[3];
+ struct traverse_info newinfo;
+ struct name_entry *p;
+
+ p = names;
+ while (!p->mode)
+ p++;
+
+ newinfo = *info;
+ newinfo.prev = info;
+ newinfo.name = *p;
+ newinfo.pathlen += tree_entry_len(p->path, p->sha1) + 1;
+ newinfo.conflicts |= df_conflicts;
+
+ for (i = 0; i < n; i++, dirmask >>= 1) {
+ const unsigned char *sha1 = NULL;
+ if (dirmask & 1)
+ sha1 = names[i].sha1;
+ fill_tree_descriptor(t+i, sha1);
+ }
+ return traverse_trees(n, t, &newinfo);
+}
+
+/*
+ * Compare the traverse-path to the cache entry without actually
+ * having to generate the textual representation of the traverse
+ * path.
+ *
+ * NOTE! This *only* compares up to the size of the traverse path
+ * itself - the caller needs to do the final check for the cache
+ * entry having more data at the end!
+ */
+static int do_compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
+{
+ int len, pathlen, ce_len;
+ const char *ce_name;
+
+ if (info->prev) {
+ int cmp = do_compare_entry(ce, info->prev, &info->name);
+ if (cmp)
+ return cmp;
+ }
+ pathlen = info->pathlen;
+ ce_len = ce_namelen(ce);
+
+ /* If ce_len < pathlen then we must have previously hit "name == directory" entry */
+ if (ce_len < pathlen)
+ return -1;
+
+ ce_len -= pathlen;
+ ce_name = ce->name + pathlen;
+
+ len = tree_entry_len(n->path, n->sha1);
+ return df_name_compare(ce_name, ce_len, S_IFREG, n->path, len, n->mode);
+}
+
+static int compare_entry(const struct cache_entry *ce, const struct traverse_info *info, const struct name_entry *n)
+{
+ int cmp = do_compare_entry(ce, info, n);
+ if (cmp)
+ return cmp;
+
+ /*
+ * Even if the beginning compared identically, the ce should
+ * compare as bigger than a directory leading up to it!
+ */
+ return ce_namelen(ce) > traverse_path_len(info, n);
+}
+
+static struct cache_entry *create_ce_entry(const struct traverse_info *info, const struct name_entry *n, int stage)
+{
+ int len = traverse_path_len(info, n);
+ struct cache_entry *ce = xcalloc(1, cache_entry_size(len));
+
+ ce->ce_mode = create_ce_mode(n->mode);
+ ce->ce_flags = create_ce_flags(len, stage);
+ hashcpy(ce->sha1, n->sha1);
+ make_traverse_path(ce->name, info, n);
+
+ return ce;
+}
+
+static int unpack_nondirectories(int n, unsigned long mask, unsigned long dirmask, struct cache_entry *src[5],
+ const struct name_entry *names, const struct traverse_info *info)
+{
+ int i;
+ struct unpack_trees_options *o = info->data;
+ unsigned long conflicts;
+
+ /* Do we have *only* directories? Nothing to do */
+ if (mask == dirmask && !src[0])
+ return 0;
+
+ conflicts = info->conflicts;
+ if (o->merge)
+ conflicts >>= 1;
+ conflicts |= dirmask;
+
+ /*
+ * Ok, we've filled in up to any potential index entry in src[0],
+ * now do the rest.
+ */
+ for (i = 0; i < n; i++) {
+ int stage;
+ unsigned int bit = 1ul << i;
+ if (conflicts & bit) {
+ src[i + o->merge] = o->df_conflict_entry;
+ continue;
+ }
+ if (!(mask & bit))
+ continue;
+ if (!o->merge)
+ stage = 0;
+ else if (i + 1 < o->head_idx)
+ stage = 1;
+ else if (i + 1 > o->head_idx)
+ stage = 3;
+ else
+ stage = 2;
+ src[i + o->merge] = create_ce_entry(info, names + i, stage);
+ }
+
+ if (o->merge)
+ return call_unpack_fn(src, o);
+
+ n += o->merge;
+ for (i = 0; i < n; i++)
+ add_entry(o, src[i], 0, 0);
+ return 0;
+}
+
+static int unpack_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *names, struct traverse_info *info)
+{
+ struct cache_entry *src[5] = { NULL, };
+ struct unpack_trees_options *o = info->data;
+ const struct name_entry *p = names;
+
+ /* Find first entry with a real name (we could use "mask" too) */
+ while (!p->mode)
+ p++;
+
+ /* Are we supposed to look at the index too? */
+ if (o->merge) {
+ while (o->pos < o->src_index->cache_nr) {
+ struct cache_entry *ce = o->src_index->cache[o->pos];
+ int cmp = compare_entry(ce, info, p);
+ if (cmp < 0) {
+ if (unpack_index_entry(ce, o) < 0)
+ return -1;
+ continue;
+ }
+ if (!cmp) {
+ o->pos++;
+ if (ce_stage(ce)) {
+ /*
+ * If we skip unmerged index entries, we'll skip this
+ * entry *and* the tree entries associated with it!
+ */
+ if (o->skip_unmerged) {
+ add_entry(o, ce, 0, 0);
+ return mask;
+ }
+ }
+ src[0] = ce;
+ }
+ break;
+ }
+ }
+
+ if (unpack_nondirectories(n, mask, dirmask, src, names, info) < 0)
+ return -1;
+
+ /* Now handle any directories.. */
+ if (dirmask) {
+ unsigned long conflicts = mask & ~dirmask;
+ if (o->merge) {
+ conflicts <<= 1;
+ if (src[0])
+ conflicts |= 1;
+ }
+ if (traverse_trees_recursive(n, dirmask, conflicts,
+ names, info) < 0)
+ return -1;
+ return mask;
+ }
+
+ return mask;
+}
+
+static int unpack_failed(struct unpack_trees_options *o, const char *message)
+{
+ discard_index(&o->result);
+ if (!o->gently) {
+ if (message)
+ return error(message);
+ return -1;
+ }
+ return -1;
+}
+
+int unpack_trees(unsigned len, struct tree_desc *t, struct unpack_trees_options *o)
+{
+ static struct cache_entry *dfc;
+
+ if (len > 4)
+ die("unpack_trees takes at most four trees");
+ memset(&state, 0, sizeof(state));
+ state.base_dir = "";
+ state.force = 1;
+ state.quiet = 1;
+ state.refresh_cache = 1;
+
+ memset(&o->result, 0, sizeof(o->result));
+ o->merge_size = len;
+
+ if (!dfc)
+ dfc = xcalloc(1, sizeof(struct cache_entry) + 1);
+ o->df_conflict_entry = dfc;
+
+ if (len) {
+ const char *prefix = o->prefix ? o->prefix : "";
+ struct traverse_info info;
+
+ setup_traverse_info(&info, prefix);
+ info.fn = unpack_callback;
+ info.data = o;
+
+ if (traverse_trees(len, t, &info) < 0)
+ return unpack_failed(o, NULL);
+ }
+
+ /* Any left-over entries in the index? */
+ if (o->merge) {
+ while (o->pos < o->src_index->cache_nr) {
+ struct cache_entry *ce = o->src_index->cache[o->pos];
+ if (unpack_index_entry(ce, o) < 0)
+ return unpack_failed(o, NULL);
+ }
+ }
+
+ if (o->trivial_merges_only && o->nontrivial_merge)
+ return unpack_failed(o, "Merge requires file-level merging");
+
+ o->src_index = NULL;
+ check_updates(o);
+ if (o->dst_index)
+ *o->dst_index = o->result;
+ return 0;
+}
+
+/* Here come the merge functions */
+
+static int reject_merge(struct cache_entry *ce)
+{
+ return error("Entry '%s' would be overwritten by merge. Cannot merge.",
+ ce->name);
+}
+
+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 &&
+ !hashcmp(a->sha1, b->sha1);
+}
+
+
+/*
+ * When a CE gets turned into an unmerged entry, we
+ * want it to be up-to-date
+ */
+static int verify_uptodate(struct cache_entry *ce,
+ struct unpack_trees_options *o)
+{
+ struct stat st;
+
+ if (o->index_only || o->reset)
+ return 0;
+
+ if (!lstat(ce->name, &st)) {
+ unsigned changed = ie_match_stat(o->src_index, ce, &st, CE_MATCH_IGNORE_VALID);
+ if (!changed)
+ return 0;
+ /*
+ * NEEDSWORK: the current default policy is to allow
+ * submodule to be out of sync wrt the supermodule
+ * index. This needs to be tightened later for
+ * submodules that are marked to be automatically
+ * checked out.
+ */
+ if (S_ISGITLINK(ce->ce_mode))
+ return 0;
+ errno = 0;
+ }
+ if (errno == ENOENT)
+ return 0;
+ return o->gently ? -1 :
+ error("Entry '%s' not uptodate. Cannot merge.", ce->name);
+}
+
+static void invalidate_ce_path(struct cache_entry *ce, struct unpack_trees_options *o)
+{
+ if (ce)
+ cache_tree_invalidate_path(o->src_index->cache_tree, ce->name);
+}
+
+/*
+ * Check that checking out ce->sha1 in subdir ce->name is not
+ * going to overwrite any working files.
+ *
+ * Currently, git does not checkout subprojects during a superproject
+ * checkout, so it is not going to overwrite anything.
+ */
+static int verify_clean_submodule(struct cache_entry *ce, const char *action,
+ struct unpack_trees_options *o)
+{
+ return 0;
+}
+
+static int verify_clean_subdirectory(struct cache_entry *ce, const char *action,
+ struct unpack_trees_options *o)
+{
+ /*
+ * we are about to extract "ce->name"; we would not want to lose
+ * anything in the existing directory there.
+ */
+ int namelen;
+ int pos, i;
+ struct dir_struct d;
+ char *pathbuf;
+ int cnt = 0;
+ unsigned char sha1[20];
+
+ if (S_ISGITLINK(ce->ce_mode) &&
+ resolve_gitlink_ref(ce->name, "HEAD", sha1) == 0) {
+ /* If we are not going to update the submodule, then
+ * we don't care.
+ */
+ if (!hashcmp(sha1, ce->sha1))
+ return 0;
+ return verify_clean_submodule(ce, action, o);
+ }
+
+ /*
+ * First let's make sure we do not have a local modification
+ * in that directory.
+ */
+ namelen = strlen(ce->name);
+ pos = index_name_pos(o->src_index, ce->name, namelen);
+ if (0 <= pos)
+ return cnt; /* we have it as nondirectory */
+ pos = -pos - 1;
+ for (i = pos; i < o->src_index->cache_nr; i++) {
+ struct cache_entry *ce = o->src_index->cache[i];
+ int len = ce_namelen(ce);
+ if (len < namelen ||
+ strncmp(ce->name, ce->name, namelen) ||
+ ce->name[namelen] != '/')
+ break;
+ /*
+ * ce->name is an entry in the subdirectory.
+ */
+ if (!ce_stage(ce)) {
+ if (verify_uptodate(ce, o))
+ return -1;
+ add_entry(o, ce, CE_REMOVE, 0);
+ }
+ cnt++;
+ }
+
+ /*
+ * Then we need to make sure that we do not lose a locally
+ * present file that is not ignored.
+ */
+ pathbuf = xmalloc(namelen + 2);
+ memcpy(pathbuf, ce->name, namelen);
+ strcpy(pathbuf+namelen, "/");
+
+ memset(&d, 0, sizeof(d));
+ if (o->dir)
+ d.exclude_per_dir = o->dir->exclude_per_dir;
+ i = read_directory(&d, ce->name, pathbuf, namelen+1, NULL);
+ if (i)
+ return o->gently ? -1 :
+ error("Updating '%s' would lose untracked files in it",
+ ce->name);
+ free(pathbuf);
+ return cnt;
+}
+
+/*
+ * We do not want to remove or overwrite a working tree file that
+ * is not tracked, unless it is ignored.
+ */
+static int verify_absent(struct cache_entry *ce, const char *action,
+ struct unpack_trees_options *o)
+{
+ struct stat st;
+
+ if (o->index_only || o->reset || !o->update)
+ return 0;
+
+ if (has_symlink_leading_path(ce->name, NULL))
+ return 0;
+
+ if (!lstat(ce->name, &st)) {
+ int cnt;
+ int dtype = ce_to_dtype(ce);
+
+ if (o->dir && excluded(o->dir, ce->name, &dtype))
+ /*
+ * ce->name is explicitly excluded, so it is Ok to
+ * overwrite it.
+ */
+ return 0;
+ if (S_ISDIR(st.st_mode)) {
+ /*
+ * We are checking out path "foo" and
+ * found "foo/." in the working tree.
+ * This is tricky -- if we have modified
+ * files that are in "foo/" we would lose
+ * it.
+ */
+ cnt = verify_clean_subdirectory(ce, action, o);
+
+ /*
+ * If this removed entries from the index,
+ * what that means is:
+ *
+ * (1) the caller unpack_trees_rec() saw path/foo
+ * in the index, and it has not removed it because
+ * it thinks it is handling 'path' as blob with
+ * D/F conflict;
+ * (2) we will return "ok, we placed a merged entry
+ * in the index" which would cause o->pos to be
+ * incremented by one;
+ * (3) however, original o->pos now has 'path/foo'
+ * marked with "to be removed".
+ *
+ * We need to increment it by the number of
+ * deleted entries here.
+ */
+ o->pos += cnt;
+ return 0;
+ }
+
+ /*
+ * The previous round may already have decided to
+ * delete this path, which is in a subdirectory that
+ * is being replaced with a blob.
+ */
+ cnt = index_name_pos(&o->result, ce->name, strlen(ce->name));
+ if (0 <= cnt) {
+ struct cache_entry *ce = o->result.cache[cnt];
+ if (ce->ce_flags & CE_REMOVE)
+ return 0;
+ }
+
+ return o->gently ? -1 :
+ error("Untracked working tree file '%s' "
+ "would be %s by merge.", ce->name, action);
+ }
+ return 0;
+}
+
+static int merged_entry(struct cache_entry *merge, struct cache_entry *old,
+ struct unpack_trees_options *o)
+{
+ 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)) {
+ copy_cache_entry(merge, old);
+ } else {
+ if (verify_uptodate(old, o))
+ return -1;
+ invalidate_ce_path(old, o);
+ }
+ }
+ else {
+ if (verify_absent(merge, "overwritten", o))
+ return -1;
+ invalidate_ce_path(merge, o);
+ }
+
+ add_entry(o, merge, CE_UPDATE, CE_STAGEMASK);
+ return 1;
+}
+
+static int deleted_entry(struct cache_entry *ce, struct cache_entry *old,
+ struct unpack_trees_options *o)
+{
+ /* Did it exist in the index? */
+ if (!old) {
+ if (verify_absent(ce, "removed", o))
+ return -1;
+ return 0;
+ }
+ if (verify_uptodate(old, o))
+ return -1;
+ add_entry(o, ce, CE_REMOVE, 0);
+ invalidate_ce_path(ce, o);
+ return 1;
+}
+
+static int keep_entry(struct cache_entry *ce, struct unpack_trees_options *o)
+{
+ add_entry(o, ce, 0, 0);
+ 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,
+ ce->ce_mode,
+ sha1_to_hex(ce->sha1),
+ ce_stage(ce),
+ ce->name);
+}
+#endif
+
+int threeway_merge(struct cache_entry **stages, struct unpack_trees_options *o)
+{
+ 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;
+
+ 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] || stages[i] == o->df_conflict_entry)
+ any_anc_missing = 1;
+ else
+ 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;
+ }
+
+ /* 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;
+ }
+ }
+ }
+
+ /* 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))
+ return o->gently ? -1 : 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))
+ return o->gently ? -1 : 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;
+ struct cache_entry *ce = NULL;
+
+ if (index)
+ ce = index;
+ else if (head)
+ ce = head;
+ else if (remote)
+ ce = remote;
+ else {
+ for (i = 1; i < o->head_idx; i++) {
+ if (stages[i] && stages[i] != o->df_conflict_entry) {
+ ce = stages[i];
+ break;
+ }
+ }
+ }
+
+ /*
+ * 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);
+ if (ce && !head_deleted) {
+ if (verify_absent(ce, "removed", o))
+ return -1;
+ }
+ return 0;
+ }
+ /*
+ * Added in both, identically.
+ */
+ if (no_anc_exists && head && remote && same(head, remote))
+ return merged_entry(head, index, o);
+
+ }
+
+ /* 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) {
+ if (verify_uptodate(index, o))
+ return -1;
+ }
+
+ o->nontrivial_merge = 1;
+
+ /* #2, #3, #4, #6, #7, #9, #10, #11. */
+ count = 0;
+ if (!head_match || !remote_match) {
+ for (i = 1; i < o->head_idx; i++) {
+ if (stages[i] && stages[i] != o->df_conflict_entry) {
+ keep_entry(stages[i], o);
+ 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, o); }
+ if (remote) { count += keep_entry(remote, o); }
+ 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>.
+ *
+ */
+int twoway_merge(struct cache_entry **src, struct unpack_trees_options *o)
+{
+ struct cache_entry *current = src[0];
+ struct cache_entry *oldtree = src[1];
+ struct cache_entry *newtree = src[2];
+
+ if (o->merge_size != 2)
+ return error("Cannot do a twoway merge of %d trees",
+ o->merge_size);
+
+ if (oldtree == o->df_conflict_entry)
+ oldtree = NULL;
+ if (newtree == o->df_conflict_entry)
+ newtree = NULL;
+
+ 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, o);
+ }
+ 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)
+ return o->gently ? -1 : reject_merge(oldtree);
+ if (current)
+ return o->gently ? -1 : reject_merge(current);
+ if (newtree)
+ return o->gently ? -1 : reject_merge(newtree);
+ return -1;
+ }
+ }
+ else if (newtree)
+ return merged_entry(newtree, current, o);
+ 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.
+ */
+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)
+ return o->gently ? -1 :
+ error("Entry '%s' overlaps with '%s'. Cannot bind.", a->name, old->name);
+ if (!a)
+ return keep_entry(old, o);
+ else
+ return merged_entry(a, NULL, o);
+}
+
+/*
+ * One-way merge.
+ *
+ * The rule is:
+ * - take the stat information from stage0, take the data from stage1
+ */
+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)) {
+ int update = 0;
+ if (o->reset) {
+ struct stat st;
+ if (lstat(old->name, &st) ||
+ ie_match_stat(o->src_index, old, &st, CE_MATCH_IGNORE_VALID))
+ update |= CE_UPDATE;
+ }
+ add_entry(o, old, update, 0);
+ return 0;
+ }
+ return merged_entry(a, old, o);
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-25 00:16:43 +0000