#include "cache.h" #include "tree-walk.h" #include "xdiff-interface.h" #include "blob.h" static const char merge_tree_usage[] = "git-merge-tree <base-tree> <branch1> <branch2>"; static int resolve_directories = 1; struct merge_list { struct merge_list *next; struct merge_list *link; /* other stages for this object */ unsigned int stage : 2, flags : 30; 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"; } extern void *merge_file(struct blob *, struct blob *, struct blob *, unsigned long *); static void *result(struct merge_list *entry, unsigned long *size) { char type[20]; struct blob *base, *our, *their; if (!entry->stage) return read_sha1_file(entry->blob->object.sha1, 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_file(base, our, their, size); } static void *origin(struct merge_list *entry, unsigned long *size) { char type[20]; while (entry) { if (entry->stage == 2) return read_sha1_file(entry->blob->object.sha1, 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 = XDF_NEED_MINIMAL; xecfg.ctxlen = 3; xecfg.flags = 0; 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; xdl_diff(&src, &dst, &xpp, &xecfg, &ecb); 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, sha1_to_hex(entry->blob->object.sha1), 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->sha1 && b->sha1 && !hashcmp(a->sha1, b->sha1) && a->mode == b->mode; } static struct merge_list *create_entry(unsigned stage, unsigned mode, const unsigned char *sha1, const char *path) { struct merge_list *res = xmalloc(sizeof(*res)); memset(res, 0, sizeof(*res)); res->stage = stage; res->path = path; res->mode = mode; res->blob = lookup_blob(sha1); return res; } static void resolve(const char *base, struct name_entry *branch1, struct name_entry *result) { struct merge_list *orig, *final; const char *path; /* If it's already branch1, don't bother showing it */ if (!branch1) return; path = xstrdup(mkpath("%s%s", base, result->path)); orig = create_entry(2, branch1->mode, branch1->sha1, path); final = create_entry(0, result->mode, result->sha1, path); final->link = orig; add_merge_entry(final); } static int unresolved_directory(const char *base, struct name_entry n[3]) { int baselen; char *newbase; struct name_entry *p; struct tree_desc t[3]; void *buf0, *buf1, *buf2; if (!resolve_directories) return 0; p = n; if (!p->mode) { p++; if (!p->mode) p++; } if (!S_ISDIR(p->mode)) return 0; baselen = strlen(base); newbase = xmalloc(baselen + p->pathlen + 2); memcpy(newbase, base, baselen); memcpy(newbase + baselen, p->path, p->pathlen); memcpy(newbase + baselen + p->pathlen, "/", 2); buf0 = fill_tree_descriptor(t+0, n[0].sha1); buf1 = fill_tree_descriptor(t+1, n[1].sha1); buf2 = fill_tree_descriptor(t+2, n[2].sha1); merge_trees(t, newbase); free(buf0); free(buf1); free(buf2); free(newbase); return 1; } static struct merge_list *link_entry(unsigned stage, const char *base, 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 = xstrdup(mkpath("%s%s", base, n->path)); link = create_entry(stage, n->mode, n->sha1, path); link->link = entry; return link; } static void unresolved(const char *base, struct name_entry n[3]) { struct merge_list *entry = NULL; if (unresolved_directory(base, n)) return; /* * Do them in reverse order so that the resulting link * list has the stages in order - link_entry adds new * links at the front. */ entry = link_entry(3, base, n + 2, entry); entry = link_entry(2, base, n + 1, entry); entry = link_entry(1, base, 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 void threeway_callback(int n, unsigned long mask, struct name_entry *entry, const char *base) { /* Same in both? */ if (same_entry(entry+1, entry+2)) { if (entry[0].sha1) { resolve(base, NULL, entry+1); return; } } if (same_entry(entry+0, entry+1)) { if (entry[2].sha1 && !S_ISDIR(entry[2].mode)) { resolve(base, entry+1, entry+2); return; } } if (same_entry(entry+0, entry+2)) { if (entry[1].sha1 && !S_ISDIR(entry[1].mode)) { resolve(base, NULL, entry+1); return; } } unresolved(base, entry); } static void merge_trees(struct tree_desc t[3], const char *base) { traverse_trees(3, t, base, threeway_callback); } static void *get_tree_descriptor(struct tree_desc *desc, const char *rev) { unsigned char sha1[20]; void *buf; if (get_sha1(rev, sha1)) die("unknown rev %s", rev); buf = fill_tree_descriptor(desc, sha1); if (!buf) die("%s is not a tree", rev); return buf; } int main(int argc, char **argv) { struct tree_desc t[3]; void *buf1, *buf2, *buf3; if (argc != 4) usage(merge_tree_usage); setup_git_directory(); 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; }