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![Junio C Hamano](/assets/img/avatar_default.png)
Introduce tree-walk.[ch] and move "struct tree_desc" and associated functions from various places. Rename DIFF_FILE_CANON_MODE(mode) macro to canon_mode(mode) and move it to cache.h. This macro returns the canonicalized st_mode value in the host byte order for files, symlinks and directories -- to be compared with a tree_desc entry. create_ce_mode(mode) in cache.h is similar but is intended to be used for index entries (so it does not work for directories) and returns the value in the network byte order. Signed-off-by: Junio C Hamano <junkio@cox.net>
179 lines
4.4 KiB
C
179 lines
4.4 KiB
C
#include "cache.h"
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#include "tree-walk.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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static void merge_trees(struct tree_desc t[3], const char *base);
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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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!memcmp(a->sha1, b->sha1, 20) &&
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a->mode == b->mode;
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}
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static const char *sha1_to_hex_zero(const unsigned char *sha1)
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{
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if (sha1)
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return sha1_to_hex(sha1);
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return "0000000000000000000000000000000000000000";
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}
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static void resolve(const char *base, struct name_entry *branch1, struct name_entry *result)
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{
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char branch1_sha1[50];
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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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memcpy(branch1_sha1, sha1_to_hex_zero(branch1->sha1), 41);
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printf("0 %06o->%06o %s->%s %s%s\n",
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branch1->mode, result->mode,
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branch1_sha1, sha1_to_hex_zero(result->sha1),
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base, result->path);
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}
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static int unresolved_directory(const char *base, struct name_entry n[3])
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{
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int baselen;
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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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baselen = strlen(base);
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newbase = xmalloc(baselen + p->pathlen + 2);
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memcpy(newbase, base, baselen);
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memcpy(newbase + baselen, p->path, p->pathlen);
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memcpy(newbase + baselen + p->pathlen, "/", 2);
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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 void unresolved(const char *base, struct name_entry n[3])
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{
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if (unresolved_directory(base, n))
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return;
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if (n[0].sha1)
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printf("1 %06o %s %s%s\n", n[0].mode, sha1_to_hex(n[0].sha1), base, n[0].path);
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if (n[1].sha1)
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printf("2 %06o %s %s%s\n", n[1].mode, sha1_to_hex(n[1].sha1), base, n[1].path);
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if (n[2].sha1)
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printf("3 %06o %s %s%s\n", n[2].mode, sha1_to_hex(n[2].sha1), base, n[2].path);
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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 void threeway_callback(int n, unsigned long mask, struct name_entry *entry, const char *base)
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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(base, NULL, entry+1);
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return;
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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(base, entry+1, entry+2);
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return;
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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(base, NULL, entry+1);
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return;
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}
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}
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unresolved(base, entry);
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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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traverse_trees(3, t, base, threeway_callback);
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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) < 0)
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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 main(int argc, char **argv)
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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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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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return 0;
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}
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