diff options
Diffstat (limited to 'builtin/merge-tree.c')
| -rw-r--r-- | builtin/merge-tree.c | 389 |
1 files changed, 389 insertions, 0 deletions
diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c new file mode 100644 index 000000000000..97b54caeb900 --- /dev/null +++ b/builtin/merge-tree.c @@ -0,0 +1,389 @@ +#define USE_THE_INDEX_COMPATIBILITY_MACROS +#include "builtin.h" +#include "tree-walk.h" +#include "xdiff-interface.h" +#include "object-store.h" +#include "repository.h" +#include "blob.h" +#include "exec-cmd.h" +#include "merge-blobs.h" + +static const char merge_tree_usage[] = "git merge-tree <base-tree> <branch1> <branch2>"; + +struct merge_list { + struct merge_list *next; + struct merge_list *link; /* other stages for this object */ + + unsigned int stage : 2; + unsigned int mode; + const char *path; + struct blob *blob; +}; + +static struct merge_list *merge_result, **merge_result_end = &merge_result; + +static void add_merge_entry(struct merge_list *entry) +{ + *merge_result_end = entry; + merge_result_end = &entry->next; +} + +static void merge_trees(struct tree_desc t[3], const char *base); + +static const char *explanation(struct merge_list *entry) +{ + switch (entry->stage) { + case 0: + return "merged"; + case 3: + return "added in remote"; + case 2: + if (entry->link) + return "added in both"; + return "added in local"; + } + + /* Existed in base */ + entry = entry->link; + if (!entry) + return "removed in both"; + + if (entry->link) + return "changed in both"; + + if (entry->stage == 3) + return "removed in local"; + return "removed in remote"; +} + +static void *result(struct merge_list *entry, unsigned long *size) +{ + enum object_type type; + struct blob *base, *our, *their; + const char *path = entry->path; + + if (!entry->stage) + return read_object_file(&entry->blob->object.oid, &type, size); + base = NULL; + if (entry->stage == 1) { + base = entry->blob; + entry = entry->link; + } + our = NULL; + if (entry && entry->stage == 2) { + our = entry->blob; + entry = entry->link; + } + their = NULL; + if (entry) + their = entry->blob; + return merge_blobs(the_repository->index, path, + base, our, their, size); +} + +static void *origin(struct merge_list *entry, unsigned long *size) +{ + enum object_type type; + while (entry) { + if (entry->stage == 2) + return read_object_file(&entry->blob->object.oid, + &type, size); + entry = entry->link; + } + return NULL; +} + +static int show_outf(void *priv_, mmbuffer_t *mb, int nbuf) +{ + int i; + for (i = 0; i < nbuf; i++) + printf("%.*s", (int) mb[i].size, mb[i].ptr); + return 0; +} + +static void show_diff(struct merge_list *entry) +{ + unsigned long size; + mmfile_t src, dst; + xpparam_t xpp; + xdemitconf_t xecfg; + xdemitcb_t ecb; + + xpp.flags = 0; + memset(&xecfg, 0, sizeof(xecfg)); + xecfg.ctxlen = 3; + ecb.out_hunk = NULL; + ecb.out_line = show_outf; + ecb.priv = NULL; + + src.ptr = origin(entry, &size); + if (!src.ptr) + size = 0; + src.size = size; + dst.ptr = result(entry, &size); + if (!dst.ptr) + size = 0; + dst.size = size; + if (xdi_diff(&src, &dst, &xpp, &xecfg, &ecb)) + die("unable to generate diff"); + free(src.ptr); + free(dst.ptr); +} + +static void show_result_list(struct merge_list *entry) +{ + printf("%s\n", explanation(entry)); + do { + struct merge_list *link = entry->link; + static const char *desc[4] = { "result", "base", "our", "their" }; + printf(" %-6s %o %s %s\n", desc[entry->stage], entry->mode, oid_to_hex(&entry->blob->object.oid), entry->path); + entry = link; + } while (entry); +} + +static void show_result(void) +{ + struct merge_list *walk; + + walk = merge_result; + while (walk) { + show_result_list(walk); + show_diff(walk); + walk = walk->next; + } +} + +/* An empty entry never compares same, not even to another empty entry */ +static int same_entry(struct name_entry *a, struct name_entry *b) +{ + return !is_null_oid(&a->oid) && + !is_null_oid(&b->oid) && + oideq(&a->oid, &b->oid) && + a->mode == b->mode; +} + +static int both_empty(struct name_entry *a, struct name_entry *b) +{ + return is_null_oid(&a->oid) && is_null_oid(&b->oid); +} + +static struct merge_list *create_entry(unsigned stage, unsigned mode, const struct object_id *oid, const char *path) +{ + struct merge_list *res = xcalloc(1, sizeof(*res)); + + res->stage = stage; + res->path = path; + res->mode = mode; + res->blob = lookup_blob(the_repository, oid); + return res; +} + +static char *traverse_path(const struct traverse_info *info, const struct name_entry *n) +{ + char *path = xmallocz(traverse_path_len(info, n) + the_hash_algo->rawsz); + return make_traverse_path(path, info, n); +} + +static void resolve(const struct traverse_info *info, struct name_entry *ours, struct name_entry *result) +{ + struct merge_list *orig, *final; + const char *path; + + /* If it's already ours, don't bother showing it */ + if (!ours) + return; + + path = traverse_path(info, result); + orig = create_entry(2, ours->mode, &ours->oid, path); + final = create_entry(0, result->mode, &result->oid, path); + + final->link = orig; + + add_merge_entry(final); +} + +static void unresolved_directory(const struct traverse_info *info, + struct name_entry n[3]) +{ + struct repository *r = the_repository; + char *newbase; + struct name_entry *p; + struct tree_desc t[3]; + void *buf0, *buf1, *buf2; + + for (p = n; p < n + 3; p++) { + if (p->mode && S_ISDIR(p->mode)) + break; + } + if (n + 3 <= p) + return; /* there is no tree here */ + + newbase = traverse_path(info, p); + +#define ENTRY_OID(e) (((e)->mode && S_ISDIR((e)->mode)) ? &(e)->oid : NULL) + buf0 = fill_tree_descriptor(r, t + 0, ENTRY_OID(n + 0)); + buf1 = fill_tree_descriptor(r, t + 1, ENTRY_OID(n + 1)); + buf2 = fill_tree_descriptor(r, t + 2, ENTRY_OID(n + 2)); +#undef ENTRY_OID + + merge_trees(t, newbase); + + free(buf0); + free(buf1); + free(buf2); + free(newbase); +} + + +static struct merge_list *link_entry(unsigned stage, const struct traverse_info *info, struct name_entry *n, struct merge_list *entry) +{ + const char *path; + struct merge_list *link; + + if (!n->mode) + return entry; + if (entry) + path = entry->path; + else + path = traverse_path(info, n); + link = create_entry(stage, n->mode, &n->oid, path); + link->link = entry; + return link; +} + +static void unresolved(const struct traverse_info *info, struct name_entry n[3]) +{ + struct merge_list *entry = NULL; + int i; + unsigned dirmask = 0, mask = 0; + + for (i = 0; i < 3; i++) { + mask |= (1 << i); + /* + * Treat missing entries as directories so that we return + * after unresolved_directory has handled this. + */ + if (!n[i].mode || S_ISDIR(n[i].mode)) + dirmask |= (1 << i); + } + + unresolved_directory(info, n); + + if (dirmask == mask) + return; + + if (n[2].mode && !S_ISDIR(n[2].mode)) + entry = link_entry(3, info, n + 2, entry); + if (n[1].mode && !S_ISDIR(n[1].mode)) + entry = link_entry(2, info, n + 1, entry); + if (n[0].mode && !S_ISDIR(n[0].mode)) + entry = link_entry(1, info, n + 0, entry); + + add_merge_entry(entry); +} + +/* + * Merge two trees together (t[1] and t[2]), using a common base (t[0]) + * as the origin. + * + * This walks the (sorted) trees in lock-step, checking every possible + * name. Note that directories automatically sort differently from other + * files (see "base_name_compare"), so you'll never see file/directory + * conflicts, because they won't ever compare the same. + * + * IOW, if a directory changes to a filename, it will automatically be + * seen as the directory going away, and the filename being created. + * + * Think of this as a three-way diff. + * + * The output will be either: + * - successful merge + * "0 mode sha1 filename" + * NOTE NOTE NOTE! FIXME! We really really need to walk the index + * in parallel with this too! + * + * - conflict: + * "1 mode sha1 filename" + * "2 mode sha1 filename" + * "3 mode sha1 filename" + * where not all of the 1/2/3 lines may exist, of course. + * + * The successful merge rules are the same as for the three-way merge + * in git-read-tree. + */ +static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *info) +{ + /* Same in both? */ + if (same_entry(entry+1, entry+2) || both_empty(entry+1, entry+2)) { + /* Modified, added or removed identically */ + resolve(info, NULL, entry+1); + return mask; + } + + if (same_entry(entry+0, entry+1)) { + if (!is_null_oid(&entry[2].oid) && !S_ISDIR(entry[2].mode)) { + /* We did not touch, they modified -- take theirs */ + resolve(info, entry+1, entry+2); + return mask; + } + /* + * If we did not touch a directory but they made it + * into a file, we fall through and unresolved() + * recurses down. Likewise for the opposite case. + */ + } + + if (same_entry(entry+0, entry+2) || both_empty(entry+0, entry+2)) { + /* We added, modified or removed, they did not touch -- take ours */ + resolve(info, NULL, entry+1); + return mask; + } + + unresolved(info, entry); + return mask; +} + +static void merge_trees(struct tree_desc t[3], const char *base) +{ + struct traverse_info info; + + setup_traverse_info(&info, base); + info.fn = threeway_callback; + traverse_trees(&the_index, 3, t, &info); +} + +static void *get_tree_descriptor(struct repository *r, + struct tree_desc *desc, + const char *rev) +{ + struct object_id oid; + void *buf; + + if (repo_get_oid(r, rev, &oid)) + die("unknown rev %s", rev); + buf = fill_tree_descriptor(r, desc, &oid); + if (!buf) + die("%s is not a tree", rev); + return buf; +} + +int cmd_merge_tree(int argc, const char **argv, const char *prefix) +{ + struct repository *r = the_repository; + struct tree_desc t[3]; + void *buf1, *buf2, *buf3; + + if (argc != 4) + usage(merge_tree_usage); + + buf1 = get_tree_descriptor(r, t+0, argv[1]); + buf2 = get_tree_descriptor(r, t+1, argv[2]); + buf3 = get_tree_descriptor(r, t+2, argv[3]); + merge_trees(t, ""); + free(buf1); + free(buf2); + free(buf3); + + show_result(); + return 0; +} |