Revision 883653babd8ee7ea23e6a5c392bb739348b1eb61 authored by Junio C Hamano on 13 September 2006, 06:53:27 UTC, committed by Junio C Hamano on 13 September 2006, 07:54:43 UTC
Fetch over http from a repository that uses alternates to borrow from neighbouring repositories were quite broken, apparently for some time now. We parse input and count bytes to allocate the new buffer, and when we copy into that buffer we know exactly how many bytes we want to copy from where. Using strlcpy for it was simply stupid, and the code forgot to take it into account that strlcpy terminated the string with NUL. Signed-off-by: Junio C Hamano <junkio@cox.net>
1 parent 60a6bf5
merge-tree.c
#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 &&
!memcmp(a->sha1, b->sha1, 20) &&
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 = strdup(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 = strdup(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);
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;
}
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