*
* Copyright (C) Linus Torvalds, 2005
*/
+#define DBRT_DEBUG 1
+
#include "cache.h"
-static int stage = 0;
+#include "object.h"
+#include "tree.h"
+
+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 unpack_tree(unsigned char *sha1)
-{
- void *buffer;
- unsigned long size;
- int ret;
+static int head_idx = -1;
+static int merge_size = 0;
- buffer = read_object_with_reference(sha1, "tree", &size, NULL);
- if (!buffer)
- return -1;
- ret = read_tree(buffer, size, stage, NULL);
- free(buffer);
+static struct object_list *trees = NULL;
+
+static struct cache_entry df_conflict_entry = {
+};
+
+static struct tree_entry_list df_conflict_list = {
+ .name = NULL,
+ .next = &df_conflict_list
+};
+
+typedef int (*merge_fn_t)(struct cache_entry **src);
+
+static int entcmp(char *name1, int dir1, 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 path_matches(struct cache_entry *a, struct cache_entry *b)
+static int unpack_trees_rec(struct tree_entry_list **posns, int len,
+ const char *base, merge_fn_t fn, int *indpos)
{
- int len = ce_namelen(a);
- return ce_namelen(b) == len &&
- !memcmp(a->name, b->name, len);
+ int baselen = strlen(base);
+ int src_size = len + 1;
+ do {
+ int i;
+ 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 = xmalloc(sizeof(struct cache_entry *) * src_size);
+ memset(src, 0, sizeof(struct cache_entry *) * src_size);
+
+ subposns = xmalloc(sizeof(struct tree_list_entry *) * len);
+ memset(subposns, 0, sizeof(struct tree_list_entry *) * len);
+
+ 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) {
+ any_dirs = 1;
+ parse_tree(posns[i]->item.tree);
+ subposns[i] = posns[i]->item.tree->entries;
+ 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 = xmalloc(ce_size);
+ memset(ce, 0, 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]->item.any->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 int same(struct cache_entry *a, struct cache_entry *b)
+static void reject_merge(struct cache_entry *ce)
{
- return a->ce_mode == b->ce_mode &&
- !memcmp(a->sha1, b->sha1, 20);
+ die("Entry '%s' would be overwritten by merge. Cannot merge.",
+ ce->name);
}
-
-/*
- * This removes all trivial merges that don't change the tree
- * and collapses them to state 0.
+/* 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 struct cache_entry *merge_entries(struct cache_entry *a,
- struct cache_entry *b,
- struct cache_entry *c)
+static void unlink_entry(char *name)
{
- /*
- * Ok, all three entries describe the same
- * filename, but maybe the contents or file
- * mode have changed?
- *
- * The trivial cases end up being the ones where two
- * out of three files are the same:
- * - both destinations the same, trivially take either
- * - one of the destination versions hasn't changed,
- * take the other.
- *
- * The "all entries exactly the same" case falls out as
- * a special case of any of the "two same" cases.
- *
- * Here "a" is "original", and "b" and "c" are the two
- * trees we are merging.
- */
- if (a && b && c) {
- if (same(b,c))
- return c;
- if (same(a,b))
- return c;
- if (same(a,c))
- return b;
+ 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 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);
+ while (nr--) {
+ struct cache_entry *ce = *src++;
+ 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);
+ }
+ }
+}
+
+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] = ((struct tree *) posn->item)->entries;
+ posn = posn->next;
+ }
+ if (unpack_trees_rec(posns, len, "", fn, &indpos))
+ return -1;
}
- return NULL;
+
+ 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
{
struct stat st;
+ if (index_only)
+ return;
+
if (!lstat(ce->name, &st)) {
- unsigned changed = ce_match_stat(ce, &st);
+ unsigned changed = ce_match_stat(ce, &st, 1);
if (!changed)
return;
errno = 0;
die("Entry '%s' not uptodate. Cannot merge.", ce->name);
}
-/*
- * If the old tree contained a CE that isn't even in the
- * result, that's always a problem, regardless of whether
- * it's up-to-date or not (ie it can be a file that we
- * have updated but not committed yet).
- */
-static void reject_merge(struct cache_entry *ce)
-{
- die("Entry '%s' would be overwritten by merge. Cannot merge.", ce->name);
-}
-
-static int merged_entry_internal(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst, int allow_dirty)
+static int merged_entry(struct cache_entry *merge, struct cache_entry *old)
{
merge->ce_flags |= htons(CE_UPDATE);
if (old) {
*/
if (same(old, merge)) {
*merge = *old;
- } else if (!allow_dirty) {
+ } else {
verify_uptodate(old);
}
}
merge->ce_flags &= ~htons(CE_STAGEMASK);
- *dst++ = merge;
+ add_cache_entry(merge, ADD_CACHE_OK_TO_ADD);
return 1;
}
-static int merged_entry_allow_dirty(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst)
+static int deleted_entry(struct cache_entry *ce, struct cache_entry *old)
{
- return merged_entry_internal(merge, old, dst, 1);
+ if (old)
+ verify_uptodate(old);
+ ce->ce_mode = 0;
+ add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
+ return 1;
}
-static int merged_entry(struct cache_entry *merge, struct cache_entry *old, struct cache_entry **dst)
+static int keep_entry(struct cache_entry *ce)
{
- return merged_entry_internal(merge, old, dst, 0);
+ add_cache_entry(ce, ADD_CACHE_OK_TO_ADD);
+ return 1;
}
-static int deleted_entry(struct cache_entry *ce, struct cache_entry *old, struct cache_entry **dst)
+#if DBRT_DEBUG
+static void show_stage_entry(FILE *o,
+ const char *label, const struct cache_entry *ce)
{
- if (old)
- verify_uptodate(old);
- ce->ce_mode = 0;
- *dst++ = ce;
- return 1;
+ 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 causes_df_conflict(struct cache_entry *ce, int stage,
- struct cache_entry **dst_,
- struct cache_entry **next_,
- int tail)
+static int threeway_merge(struct cache_entry **stages)
{
- /* This is called during the merge operation and walking
- * the active_cache[] array is messy, because it is in the
- * middle of overlapping copy operation. The invariants
- * are:
- * (1) active_cache points at the first (zeroth) entry.
- * (2) up to dst pointer are resolved entries.
- * (3) from the next pointer (head-inclusive) to the tail
- * of the active_cache array have the remaining paths
- * to be processed. There can be a gap between dst
- * and next. Note that next is called "src" in the
- * merge_cache() function, and tail is the original
- * end of active_cache array when merge_cache() started.
- * (4) the path corresponding to *ce is not found in (2)
- * or (3). It is in the gap.
- *
- * active_cache -----......+++++++++++++.
- * ^dst ^next ^tail
- */
- int i, next, dst;
- const char *path = ce->name;
- int namelen = ce_namelen(ce);
+ 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;
- next = next_ - active_cache;
- dst = dst_ - active_cache;
+ int df_conflict_head = 0;
+ int df_conflict_remote = 0;
- for (i = 0; i < tail; i++) {
- int entlen, len;
- const char *one, *two;
- if (dst <= i && i < next)
- continue;
- ce = active_cache[i];
- if (ce_stage(ce) != stage)
- continue;
- /* If ce->name is a prefix of path, then path is a file
- * that hangs underneath ce->name, which is bad.
- * If path is a prefix of ce->name, then it is the
- * other way around which also is bad.
- */
- entlen = ce_namelen(ce);
- if (namelen == entlen)
- continue;
- if (namelen < entlen) {
- len = namelen;
- one = path;
- two = ce->name;
- } else {
- len = entlen;
- one = ce->name;
- two = path;
- }
- if (memcmp(one, two, len))
- continue;
- if (two[len] == '/')
- return 1;
+ 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
+ no_anc_exists = 0;
}
- return 0;
-}
-static int threeway_merge(struct cache_entry *stages[4],
- struct cache_entry **dst,
- struct cache_entry **next, int tail)
-{
- struct cache_entry *old = stages[0];
- struct cache_entry *a = stages[1], *b = stages[2], *c = stages[3];
- struct cache_entry *merge;
- int count;
+ index = stages[0];
+ head = stages[head_idx];
- /* #5ALT */
- if (!a && b && c && same(b, c)) {
- if (old && !same(b, old))
- return -1;
- return merged_entry_allow_dirty(b, old, dst);
+ if (head == &df_conflict_entry) {
+ df_conflict_head = 1;
+ head = NULL;
}
- /* #2ALT and #3ALT */
- if (!a && (!!b != !!c)) {
- /*
- * The reason we need to worry about directory/file
- * conflicts only in #2ALT and #3ALT case is this:
- *
- * (1) For all other cases that read-tree internally
- * resolves a path, we always have such a path in
- * *both* stage2 and stage3 when we begin.
- * Traditionally, the behaviour has been even
- * stricter and we did not resolve a path without
- * initially being in all of stage1, 2, and 3.
- *
- * (2) When read-tree finishes, all resolved paths (i.e.
- * the paths that are in stage0) must have come from
- * either stage2 or stage3. It is not possible to
- * have a stage0 path as a result of a merge if
- * neither stage2 nor stage3 had that path.
- *
- * (3) It is guaranteed that just after reading the
- * stages, each stage cannot have directory/file
- * conflicts on its own, because they are populated
- * by reading hierarchy of a tree. Combined with
- * (1) and (2) above, this means that no matter what
- * combination of paths we take from stage2 and
- * stage3 as a result of a merge, they cannot cause
- * a directory/file conflict situation (otherwise
- * the "guilty" path would have already had such a
- * conflict in the original stage, either stage2
- * or stage3). Although its stage2 is synthesized
- * by overlaying the current index on top of "our
- * head" tree, --emu23 case also has this guarantee,
- * by calling add_cache_entry() to create such stage2
- * entries.
- *
- * (4) Only #2ALT and #3ALT lack the guarantee (1).
- * They resolve paths that exist only in stage2
- * or stage3. The stage2 tree may have a file DF
- * while stage3 tree may have a file DF/DF. If
- * #2ALT and #3ALT rules happen to apply to both
- * of them, we would end up having DF (coming from
- * stage2) and DF/DF (from stage3) in the result.
- * When we attempt to resolve a path that exists
- * only in stage2, we need to make sure there is
- * no path that would conflict with it in stage3
- * and vice versa.
- */
- if (c) { /* #2ALT */
- if (!causes_df_conflict(c, 2, dst, next, tail) &&
- (!old || same(c, old)))
- return merged_entry_allow_dirty(c, old, dst);
- }
- else { /* #3ALT */
- if (!causes_df_conflict(b, 3, dst, next, tail) &&
- (!old || same(b, old)))
- return merged_entry_allow_dirty(b, old, dst);
+
+ if (remote == &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 < head_idx; i++) {
+ if (same(stages[i], head)) {
+ head_match = i;
+ }
+ if (same(stages[i], remote)) {
+ remote_match = i;
+ }
}
- /* otherwise we will apply the original rule */
}
- /* #14ALT */
- if (a && b && c && same(a, b) && !same(a, c)) {
- if (old && same(old, c))
- return merged_entry_allow_dirty(c, old, dst);
- /* otherwise the regular rule applies */
+
+ /* 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 ("old"), then we want
- * to make sure that it matches any entries in stage 2 ("first
- * branch", aka "b").
+ * If we have an entry in the index cache, then we want to
+ * make sure that it matches head.
*/
- if (old) {
- if (!b || !same(old, b))
- return -1;
+ if (index && !same(index, head)) {
+ reject_merge(index);
}
- merge = merge_entries(a, b, c);
- if (merge)
- return merged_entry(merge, old, dst);
- if (old)
- verify_uptodate(old);
+
+ 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))
+ 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);
+ }
+
+ nontrivial_merge = 1;
+
+ /* #2, #3, #4, #6, #7, #9, #11. */
count = 0;
- if (a) { *dst++ = a; count++; }
- if (b) { *dst++ = b; count++; }
- if (c) { *dst++ = c; count++; }
+ 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;
}
* "carry forward" rule, please see <Documentation/git-read-tree.txt>.
*
*/
-static int twoway_merge(struct cache_entry **src, struct cache_entry **dst,
- struct cache_entry **next, int tail)
+static int twoway_merge(struct cache_entry **src)
{
struct cache_entry *current = src[0];
struct cache_entry *oldtree = src[1], *newtree = src[2];
- if (src[3])
- return -1;
+ if (merge_size != 2)
+ return error("Cannot do a twoway merge of %d trees\n",
+ merge_size);
if (current) {
if ((!oldtree && !newtree) || /* 4 and 5 */
(oldtree && newtree &&
!same(oldtree, newtree) && /* 18 and 19*/
same(current, newtree))) {
- *dst++ = current;
- return 1;
+ return keep_entry(current);
}
else if (oldtree && !newtree && same(current, oldtree)) {
/* 10 or 11 */
- return deleted_entry(oldtree, current, dst);
+ return deleted_entry(oldtree, current);
}
else if (oldtree && newtree &&
same(current, oldtree) && !same(current, newtree)) {
/* 20 or 21 */
- return merged_entry(newtree, current, dst);
+ return merged_entry(newtree, current);
}
- else
+ 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, dst);
+ return merged_entry(newtree, current);
else
- return deleted_entry(oldtree, current, dst);
-}
-
-/*
- * Two-way merge emulated with three-way merge.
- *
- * This treats "read-tree -m H M" by transforming it internally
- * into "read-tree -m H I+H M", where I+H is a tree that would
- * contain the contents of the current index file, overlayed on
- * top of H. Unlike the traditional two-way merge, this leaves
- * the stages in the resulting index file and lets the user resolve
- * the merge conflicts using standard tools for three-way merge.
- *
- * This function is just to set-up such an arrangement, and the
- * actual merge uses threeway_merge() function.
- */
-static void setup_emu23(void)
-{
- /* stage0 contains I, stage1 H, stage2 M.
- * move stage2 to stage3, and create stage2 entries
- * by scanning stage0 and stage1 entries.
- */
- int i, namelen, size;
- struct cache_entry *ce, *stage2;
-
- for (i = 0; i < active_nr; i++) {
- ce = active_cache[i];
- if (ce_stage(ce) != 2)
- continue;
- /* hoist them up to stage 3 */
- namelen = ce_namelen(ce);
- ce->ce_flags = create_ce_flags(namelen, 3);
- }
-
- for (i = 0; i < active_nr; i++) {
- ce = active_cache[i];
- if (ce_stage(ce) > 1)
- continue;
- namelen = ce_namelen(ce);
- size = cache_entry_size(namelen);
- stage2 = xmalloc(size);
- memcpy(stage2, ce, size);
- stage2->ce_flags = create_ce_flags(namelen, 2);
- if (add_cache_entry(stage2, ADD_CACHE_OK_TO_ADD) < 0)
- die("cannot merge index and our head tree");
-
- /* We are done with this name, so skip to next name */
- while (i < active_nr &&
- ce_namelen(active_cache[i]) == namelen &&
- !memcmp(active_cache[i]->name, ce->name, namelen))
- i++;
- i--; /* compensate for the loop control */
- }
+ return deleted_entry(oldtree, current);
}
/*
* 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 **dst,
- struct cache_entry **next, int tail)
+static int oneway_merge(struct cache_entry **src)
{
struct cache_entry *old = src[0];
struct cache_entry *a = src[1];
- if (src[2] || src[3])
- return -1;
+ if (merge_size != 1)
+ return error("Cannot do a oneway merge of %d trees\n",
+ merge_size);
if (!a)
return 0;
if (old && same(old, a)) {
- *dst++ = old;
- return 1;
+ return keep_entry(old);
}
- return merged_entry(a, NULL, dst);
-}
-
-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);
- while (nr--) {
- struct cache_entry *ce = *src++;
- if (!ce->ce_mode) {
- if (update)
- unlink(ce->name);
- continue;
- }
- if (ce->ce_flags & mask) {
- ce->ce_flags &= ~mask;
- if (update)
- checkout_entry(ce, &state);
- }
- }
-}
-
-typedef int (*merge_fn_t)(struct cache_entry **, struct cache_entry **, struct cache_entry **, int);
-
-static void merge_cache(struct cache_entry **src, int nr, merge_fn_t fn)
-{
- struct cache_entry **dst = src;
- int tail = nr;
-
- while (nr) {
- int entries;
- struct cache_entry *name, *ce, *stages[4] = { NULL, };
-
- name = ce = *src;
- for (;;) {
- int stage = ce_stage(ce);
- stages[stage] = ce;
- ce = *++src;
- active_nr--;
- if (!--nr)
- break;
- if (!path_matches(ce, name))
- break;
- }
-
- entries = fn(stages, dst, src, tail);
- if (entries < 0)
- reject_merge(name);
- dst += entries;
- active_nr += entries;
- }
- check_updates(active_cache, active_nr);
+ return merged_entry(a, NULL);
}
static int read_cache_unmerged(void)
return deleted;
}
-static const char read_tree_usage[] = "git-read-tree (<sha> | -m [-u] <sha1> [<sha2> [<sha3>]])";
+static const char read_tree_usage[] = "git-read-tree (<sha> | -m [-u | -i] <sha1> [<sha2> [<sha3>]])";
static struct cache_file cache_file;
int main(int argc, char **argv)
{
- int i, newfd, merge, reset, emu23;
+ int i, newfd, reset, stage = 0;
unsigned char sha1[20];
+ merge_fn_t fn = NULL;
+
+ setup_git_directory();
newfd = hold_index_file_for_update(&cache_file, get_index_file());
if (newfd < 0)
die("unable to create new cachefile");
+ git_config(git_default_config);
+
merge = 0;
reset = 0;
- emu23 = 0;
for (i = 1; i < argc; i++) {
const char *arg = argv[i];
- /* "-u" means "update", meaning that a merge will update the working directory */
+ /* "-u" means "update", meaning that a merge will update
+ * the working tree.
+ */
if (!strcmp(arg, "-u")) {
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;
+ }
+
/* This differs from "-m" in that we'll silently ignore unmerged entries */
if (!strcmp(arg, "--reset")) {
- if (stage || merge || emu23)
+ if (stage || merge)
usage(read_tree_usage);
reset = 1;
merge = 1;
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 || emu23)
+ if (stage || merge)
usage(read_tree_usage);
if (read_cache_unmerged())
die("you need to resolve your current index first");
continue;
}
- /* "-emu23" uses 3-way merge logic to perform fast-forward */
- if (!strcmp(arg, "--emu23")) {
- if (stage || merge || emu23)
- usage(read_tree_usage);
- if (read_cache_unmerged())
- die("you need to resolve your current index first");
- merge = emu23 = stage = 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) < 0)
usage(read_tree_usage);
- if (stage > 3)
- usage(read_tree_usage);
- if (unpack_tree(sha1) < 0)
+ if (list_tree(sha1) < 0)
die("failed to unpack tree object %s", arg);
stage++;
}
- if (update && !merge)
+ if ((update||index_only) && !merge)
usage(read_tree_usage);
+
if (merge) {
- static const merge_fn_t merge_function[] = {
- [1] = oneway_merge,
- [2] = twoway_merge,
- [3] = threeway_merge,
- };
- merge_fn_t fn;
-
- if (stage < 2 || stage > 4)
+ if (stage < 2)
die("just how do you expect me to merge %d trees?", stage-1);
- if (emu23 && stage != 3)
- die("--emu23 takes only two trees");
- fn = merge_function[stage-1];
- if (stage == 3 && emu23) {
- setup_emu23();
- fn = merge_function[3];
+ switch (stage - 1) {
+ case 1:
+ fn = oneway_merge;
+ break;
+ case 2:
+ fn = twoway_merge;
+ break;
+ case 3:
+ fn = threeway_merge;
+ break;
+ default:
+ fn = threeway_merge;
+ break;
}
- merge_cache(active_cache, active_nr, fn);
+
+ if (stage - 1 >= 3)
+ head_idx = stage - 2;
+ else
+ head_idx = 1;
}
+
+ unpack_trees(fn);
if (write_cache(newfd, active_cache, active_nr) ||
commit_index_file(&cache_file))
die("unable to write new index file");