make "git merge-tree" a built-in
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Linus Torvalds
committed by
Junio C Hamano
Junio C Hamano
parent
a5031214c4
commit
907a7cb51c
360
builtin-merge-tree.c
Normal file
360
builtin-merge-tree.c
Normal file
@ -0,0 +1,360 @@
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#include "cache.h"
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#include "tree-walk.h"
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#include "xdiff-interface.h"
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#include "blob.h"
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#include "exec_cmd.h"
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static const char merge_tree_usage[] = "git merge-tree <base-tree> <branch1> <branch2>";
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static int resolve_directories = 1;
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struct merge_list {
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struct merge_list *next;
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struct merge_list *link; /* other stages for this object */
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unsigned int stage : 2,
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flags : 30;
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unsigned int mode;
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const char *path;
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struct blob *blob;
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};
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static struct merge_list *merge_result, **merge_result_end = &merge_result;
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static void add_merge_entry(struct merge_list *entry)
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{
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*merge_result_end = entry;
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merge_result_end = &entry->next;
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}
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static void merge_trees(struct tree_desc t[3], const char *base);
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static const char *explanation(struct merge_list *entry)
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{
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switch (entry->stage) {
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case 0:
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return "merged";
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case 3:
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return "added in remote";
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case 2:
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if (entry->link)
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return "added in both";
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return "added in local";
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}
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/* Existed in base */
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entry = entry->link;
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if (!entry)
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return "removed in both";
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if (entry->link)
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return "changed in both";
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if (entry->stage == 3)
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return "removed in local";
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return "removed in remote";
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}
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extern void *merge_file(const char *, struct blob *, struct blob *, struct blob *, unsigned long *);
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static void *result(struct merge_list *entry, unsigned long *size)
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{
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enum object_type type;
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struct blob *base, *our, *their;
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if (!entry->stage)
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return read_sha1_file(entry->blob->object.sha1, &type, size);
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base = NULL;
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if (entry->stage == 1) {
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base = entry->blob;
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entry = entry->link;
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}
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our = NULL;
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if (entry && entry->stage == 2) {
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our = entry->blob;
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entry = entry->link;
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}
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their = NULL;
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if (entry)
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their = entry->blob;
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return merge_file(entry->path, base, our, their, size);
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}
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static void *origin(struct merge_list *entry, unsigned long *size)
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{
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enum object_type type;
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while (entry) {
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if (entry->stage == 2)
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return read_sha1_file(entry->blob->object.sha1, &type, size);
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entry = entry->link;
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}
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return NULL;
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}
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static int show_outf(void *priv_, mmbuffer_t *mb, int nbuf)
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{
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int i;
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for (i = 0; i < nbuf; i++)
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printf("%.*s", (int) mb[i].size, mb[i].ptr);
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return 0;
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}
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static void show_diff(struct merge_list *entry)
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{
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unsigned long size;
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mmfile_t src, dst;
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xpparam_t xpp;
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xdemitconf_t xecfg;
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xdemitcb_t ecb;
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xpp.flags = XDF_NEED_MINIMAL;
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memset(&xecfg, 0, sizeof(xecfg));
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xecfg.ctxlen = 3;
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ecb.outf = show_outf;
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ecb.priv = NULL;
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src.ptr = origin(entry, &size);
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if (!src.ptr)
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size = 0;
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src.size = size;
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dst.ptr = result(entry, &size);
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if (!dst.ptr)
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size = 0;
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dst.size = size;
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xdi_diff(&src, &dst, &xpp, &xecfg, &ecb);
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free(src.ptr);
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free(dst.ptr);
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}
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static void show_result_list(struct merge_list *entry)
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{
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printf("%s\n", explanation(entry));
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do {
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struct merge_list *link = entry->link;
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static const char *desc[4] = { "result", "base", "our", "their" };
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printf(" %-6s %o %s %s\n", desc[entry->stage], entry->mode, sha1_to_hex(entry->blob->object.sha1), entry->path);
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entry = link;
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} while (entry);
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}
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static void show_result(void)
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{
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struct merge_list *walk;
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walk = merge_result;
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while (walk) {
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show_result_list(walk);
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show_diff(walk);
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walk = walk->next;
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}
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}
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/* An empty entry never compares same, not even to another empty entry */
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static int same_entry(struct name_entry *a, struct name_entry *b)
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{
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return a->sha1 &&
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b->sha1 &&
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!hashcmp(a->sha1, b->sha1) &&
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a->mode == b->mode;
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}
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static struct merge_list *create_entry(unsigned stage, unsigned mode, const unsigned char *sha1, const char *path)
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{
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struct merge_list *res = xcalloc(1, sizeof(*res));
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res->stage = stage;
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res->path = path;
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res->mode = mode;
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res->blob = lookup_blob(sha1);
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return res;
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}
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static char *traverse_path(const struct traverse_info *info, const struct name_entry *n)
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{
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char *path = xmalloc(traverse_path_len(info, n) + 1);
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return make_traverse_path(path, info, n);
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}
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static void resolve(const struct traverse_info *info, struct name_entry *branch1, struct name_entry *result)
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{
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struct merge_list *orig, *final;
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const char *path;
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/* If it's already branch1, don't bother showing it */
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if (!branch1)
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return;
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path = traverse_path(info, result);
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orig = create_entry(2, branch1->mode, branch1->sha1, path);
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final = create_entry(0, result->mode, result->sha1, path);
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final->link = orig;
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add_merge_entry(final);
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}
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static int unresolved_directory(const struct traverse_info *info, struct name_entry n[3])
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{
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char *newbase;
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struct name_entry *p;
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struct tree_desc t[3];
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void *buf0, *buf1, *buf2;
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if (!resolve_directories)
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return 0;
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p = n;
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if (!p->mode) {
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p++;
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if (!p->mode)
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p++;
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}
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if (!S_ISDIR(p->mode))
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return 0;
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newbase = traverse_path(info, p);
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buf0 = fill_tree_descriptor(t+0, n[0].sha1);
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buf1 = fill_tree_descriptor(t+1, n[1].sha1);
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buf2 = fill_tree_descriptor(t+2, n[2].sha1);
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merge_trees(t, newbase);
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free(buf0);
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free(buf1);
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free(buf2);
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free(newbase);
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return 1;
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}
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static struct merge_list *link_entry(unsigned stage, const struct traverse_info *info, struct name_entry *n, struct merge_list *entry)
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{
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const char *path;
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struct merge_list *link;
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if (!n->mode)
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return entry;
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if (entry)
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path = entry->path;
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else
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path = traverse_path(info, n);
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link = create_entry(stage, n->mode, n->sha1, path);
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link->link = entry;
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return link;
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}
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static void unresolved(const struct traverse_info *info, struct name_entry n[3])
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{
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struct merge_list *entry = NULL;
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if (unresolved_directory(info, n))
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return;
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/*
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* Do them in reverse order so that the resulting link
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* list has the stages in order - link_entry adds new
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* links at the front.
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*/
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entry = link_entry(3, info, n + 2, entry);
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entry = link_entry(2, info, n + 1, entry);
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entry = link_entry(1, info, n + 0, entry);
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add_merge_entry(entry);
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}
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/*
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* Merge two trees together (t[1] and t[2]), using a common base (t[0])
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* as the origin.
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*
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* This walks the (sorted) trees in lock-step, checking every possible
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* name. Note that directories automatically sort differently from other
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* files (see "base_name_compare"), so you'll never see file/directory
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* conflicts, because they won't ever compare the same.
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*
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* IOW, if a directory changes to a filename, it will automatically be
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* seen as the directory going away, and the filename being created.
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*
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* Think of this as a three-way diff.
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*
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* The output will be either:
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* - successful merge
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* "0 mode sha1 filename"
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* NOTE NOTE NOTE! FIXME! We really really need to walk the index
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* in parallel with this too!
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*
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* - conflict:
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* "1 mode sha1 filename"
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* "2 mode sha1 filename"
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* "3 mode sha1 filename"
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* where not all of the 1/2/3 lines may exist, of course.
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*
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* The successful merge rules are the same as for the three-way merge
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* in git-read-tree.
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*/
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static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, struct name_entry *entry, struct traverse_info *info)
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{
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/* Same in both? */
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if (same_entry(entry+1, entry+2)) {
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if (entry[0].sha1) {
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resolve(info, NULL, entry+1);
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return mask;
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}
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}
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if (same_entry(entry+0, entry+1)) {
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if (entry[2].sha1 && !S_ISDIR(entry[2].mode)) {
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resolve(info, entry+1, entry+2);
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return mask;
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}
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}
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if (same_entry(entry+0, entry+2)) {
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if (entry[1].sha1 && !S_ISDIR(entry[1].mode)) {
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resolve(info, NULL, entry+1);
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return mask;
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}
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}
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unresolved(info, entry);
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return mask;
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}
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static void merge_trees(struct tree_desc t[3], const char *base)
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{
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struct traverse_info info;
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setup_traverse_info(&info, base);
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info.fn = threeway_callback;
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traverse_trees(3, t, &info);
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}
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static void *get_tree_descriptor(struct tree_desc *desc, const char *rev)
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{
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unsigned char sha1[20];
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void *buf;
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if (get_sha1(rev, sha1))
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die("unknown rev %s", rev);
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buf = fill_tree_descriptor(desc, sha1);
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if (!buf)
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die("%s is not a tree", rev);
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return buf;
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}
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int cmd_merge_tree(int argc, const char **argv, const char *prefix)
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{
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struct tree_desc t[3];
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void *buf1, *buf2, *buf3;
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if (argc != 4)
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usage(merge_tree_usage);
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git_extract_argv0_path(argv[0]);
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buf1 = get_tree_descriptor(t+0, argv[1]);
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buf2 = get_tree_descriptor(t+1, argv[2]);
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buf3 = get_tree_descriptor(t+2, argv[3]);
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merge_trees(t, "");
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free(buf1);
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free(buf2);
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free(buf3);
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show_result();
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return 0;
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}
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