#include "builtin.h" #include "tree-walk.h" #include "xdiff-interface.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(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.outf = 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 a->oid && b->oid && !oidcmp(a->oid, b->oid) && a->mode == b->mode; } static int both_empty(struct name_entry *a, struct name_entry *b) { return !(a->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(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)); 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]) { 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(t + 0, ENTRY_OID(n + 0)); buf1 = fill_tree_descriptor(t + 1, ENTRY_OID(n + 1)); buf2 = fill_tree_descriptor(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 (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(3, t, &info); } static void *get_tree_descriptor(struct tree_desc *desc, const char *rev) { struct object_id oid; void *buf; if (get_oid(rev, &oid)) die("unknown rev %s", rev); buf = fill_tree_descriptor(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 tree_desc t[3]; void *buf1, *buf2, *buf3; if (argc != 4) usage(merge_tree_usage); buf1 = get_tree_descriptor(t+0, argv[1]); buf2 = get_tree_descriptor(t+1, argv[2]); buf3 = get_tree_descriptor(t+2, argv[3]); merge_trees(t, ""); free(buf1); free(buf2); free(buf3); show_result(); return 0; }