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git/cache-tree.c
Linus Torvalds f35a6d3bce Teach core object handling functions about gitlinks
This teaches the really fundamental core SHA1 object handling routines
about gitlinks.  We can compare trees with gitlinks in them (although we
can not actually generate patches for them yet - just raw git diffs),
and they show up as commits in "git ls-tree".

We also know to compare gitlinks as if they were directories (ie the
normal "sort as trees" rules apply).

[jc: amended a cut&paste error]

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2007-04-10 13:50:43 -07:00

558 lines
12 KiB
C

#include "cache.h"
#include "tree.h"
#include "cache-tree.h"
#ifndef DEBUG
#define DEBUG 0
#endif
struct cache_tree *cache_tree(void)
{
struct cache_tree *it = xcalloc(1, sizeof(struct cache_tree));
it->entry_count = -1;
return it;
}
void cache_tree_free(struct cache_tree **it_p)
{
int i;
struct cache_tree *it = *it_p;
if (!it)
return;
for (i = 0; i < it->subtree_nr; i++)
if (it->down[i])
cache_tree_free(&it->down[i]->cache_tree);
free(it->down);
free(it);
*it_p = NULL;
}
static int subtree_name_cmp(const char *one, int onelen,
const char *two, int twolen)
{
if (onelen < twolen)
return -1;
if (twolen < onelen)
return 1;
return memcmp(one, two, onelen);
}
static int subtree_pos(struct cache_tree *it, const char *path, int pathlen)
{
struct cache_tree_sub **down = it->down;
int lo, hi;
lo = 0;
hi = it->subtree_nr;
while (lo < hi) {
int mi = (lo + hi) / 2;
struct cache_tree_sub *mdl = down[mi];
int cmp = subtree_name_cmp(path, pathlen,
mdl->name, mdl->namelen);
if (!cmp)
return mi;
if (cmp < 0)
hi = mi;
else
lo = mi + 1;
}
return -lo-1;
}
static struct cache_tree_sub *find_subtree(struct cache_tree *it,
const char *path,
int pathlen,
int create)
{
struct cache_tree_sub *down;
int pos = subtree_pos(it, path, pathlen);
if (0 <= pos)
return it->down[pos];
if (!create)
return NULL;
pos = -pos-1;
if (it->subtree_alloc <= it->subtree_nr) {
it->subtree_alloc = alloc_nr(it->subtree_alloc);
it->down = xrealloc(it->down, it->subtree_alloc *
sizeof(*it->down));
}
it->subtree_nr++;
down = xmalloc(sizeof(*down) + pathlen + 1);
down->cache_tree = NULL;
down->namelen = pathlen;
memcpy(down->name, path, pathlen);
down->name[pathlen] = 0;
if (pos < it->subtree_nr)
memmove(it->down + pos + 1,
it->down + pos,
sizeof(down) * (it->subtree_nr - pos - 1));
it->down[pos] = down;
return down;
}
struct cache_tree_sub *cache_tree_sub(struct cache_tree *it, const char *path)
{
int pathlen = strlen(path);
return find_subtree(it, path, pathlen, 1);
}
void cache_tree_invalidate_path(struct cache_tree *it, const char *path)
{
/* a/b/c
* ==> invalidate self
* ==> find "a", have it invalidate "b/c"
* a
* ==> invalidate self
* ==> if "a" exists as a subtree, remove it.
*/
const char *slash;
int namelen;
struct cache_tree_sub *down;
#if DEBUG
fprintf(stderr, "cache-tree invalidate <%s>\n", path);
#endif
if (!it)
return;
slash = strchr(path, '/');
it->entry_count = -1;
if (!slash) {
int pos;
namelen = strlen(path);
pos = subtree_pos(it, path, namelen);
if (0 <= pos) {
cache_tree_free(&it->down[pos]->cache_tree);
free(it->down[pos]);
/* 0 1 2 3 4 5
* ^ ^subtree_nr = 6
* pos
* move 4 and 5 up one place (2 entries)
* 2 = 6 - 3 - 1 = subtree_nr - pos - 1
*/
memmove(it->down+pos, it->down+pos+1,
sizeof(struct cache_tree_sub *) *
(it->subtree_nr - pos - 1));
it->subtree_nr--;
}
return;
}
namelen = slash - path;
down = find_subtree(it, path, namelen, 0);
if (down)
cache_tree_invalidate_path(down->cache_tree, slash + 1);
}
static int verify_cache(struct cache_entry **cache,
int entries)
{
int i, funny;
/* Verify that the tree is merged */
funny = 0;
for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
if (ce_stage(ce)) {
if (10 < ++funny) {
fprintf(stderr, "...\n");
break;
}
fprintf(stderr, "%s: unmerged (%s)\n",
ce->name, sha1_to_hex(ce->sha1));
}
}
if (funny)
return -1;
/* Also verify that the cache does not have path and path/file
* at the same time. At this point we know the cache has only
* stage 0 entries.
*/
funny = 0;
for (i = 0; i < entries - 1; i++) {
/* path/file always comes after path because of the way
* the cache is sorted. Also path can appear only once,
* which means conflicting one would immediately follow.
*/
const char *this_name = cache[i]->name;
const char *next_name = cache[i+1]->name;
int this_len = strlen(this_name);
if (this_len < strlen(next_name) &&
strncmp(this_name, next_name, this_len) == 0 &&
next_name[this_len] == '/') {
if (10 < ++funny) {
fprintf(stderr, "...\n");
break;
}
fprintf(stderr, "You have both %s and %s\n",
this_name, next_name);
}
}
if (funny)
return -1;
return 0;
}
static void discard_unused_subtrees(struct cache_tree *it)
{
struct cache_tree_sub **down = it->down;
int nr = it->subtree_nr;
int dst, src;
for (dst = src = 0; src < nr; src++) {
struct cache_tree_sub *s = down[src];
if (s->used)
down[dst++] = s;
else {
cache_tree_free(&s->cache_tree);
free(s);
it->subtree_nr--;
}
}
}
int cache_tree_fully_valid(struct cache_tree *it)
{
int i;
if (!it)
return 0;
if (it->entry_count < 0 || !has_sha1_file(it->sha1))
return 0;
for (i = 0; i < it->subtree_nr; i++) {
if (!cache_tree_fully_valid(it->down[i]->cache_tree))
return 0;
}
return 1;
}
static int update_one(struct cache_tree *it,
struct cache_entry **cache,
int entries,
const char *base,
int baselen,
int missing_ok,
int dryrun)
{
unsigned long size, offset;
char *buffer;
int i;
if (0 <= it->entry_count && has_sha1_file(it->sha1))
return it->entry_count;
/*
* We first scan for subtrees and update them; we start by
* marking existing subtrees -- the ones that are unmarked
* should not be in the result.
*/
for (i = 0; i < it->subtree_nr; i++)
it->down[i]->used = 0;
/*
* Find the subtrees and update them.
*/
for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
struct cache_tree_sub *sub;
const char *path, *slash;
int pathlen, sublen, subcnt;
path = ce->name;
pathlen = ce_namelen(ce);
if (pathlen <= baselen || memcmp(base, path, baselen))
break; /* at the end of this level */
slash = strchr(path + baselen, '/');
if (!slash)
continue;
/*
* a/bbb/c (base = a/, slash = /c)
* ==>
* path+baselen = bbb/c, sublen = 3
*/
sublen = slash - (path + baselen);
sub = find_subtree(it, path + baselen, sublen, 1);
if (!sub->cache_tree)
sub->cache_tree = cache_tree();
subcnt = update_one(sub->cache_tree,
cache + i, entries - i,
path,
baselen + sublen + 1,
missing_ok,
dryrun);
if (subcnt < 0)
return subcnt;
i += subcnt - 1;
sub->used = 1;
}
discard_unused_subtrees(it);
/*
* Then write out the tree object for this level.
*/
size = 8192;
buffer = xmalloc(size);
offset = 0;
for (i = 0; i < entries; i++) {
struct cache_entry *ce = cache[i];
struct cache_tree_sub *sub;
const char *path, *slash;
int pathlen, entlen;
const unsigned char *sha1;
unsigned mode;
path = ce->name;
pathlen = ce_namelen(ce);
if (pathlen <= baselen || memcmp(base, path, baselen))
break; /* at the end of this level */
slash = strchr(path + baselen, '/');
if (slash) {
entlen = slash - (path + baselen);
sub = find_subtree(it, path + baselen, entlen, 0);
if (!sub)
die("cache-tree.c: '%.*s' in '%s' not found",
entlen, path + baselen, path);
i += sub->cache_tree->entry_count - 1;
sha1 = sub->cache_tree->sha1;
mode = S_IFDIR;
}
else {
sha1 = ce->sha1;
mode = ntohl(ce->ce_mode);
entlen = pathlen - baselen;
}
if (mode != S_IFDIRLNK && !missing_ok && !has_sha1_file(sha1))
return error("invalid object %s", sha1_to_hex(sha1));
if (!ce->ce_mode)
continue; /* entry being removed */
if (size < offset + entlen + 100) {
size = alloc_nr(offset + entlen + 100);
buffer = xrealloc(buffer, size);
}
offset += sprintf(buffer + offset,
"%o %.*s", mode, entlen, path + baselen);
buffer[offset++] = 0;
hashcpy((unsigned char*)buffer + offset, sha1);
offset += 20;
#if DEBUG
fprintf(stderr, "cache-tree update-one %o %.*s\n",
mode, entlen, path + baselen);
#endif
}
if (dryrun)
hash_sha1_file(buffer, offset, tree_type, it->sha1);
else
write_sha1_file(buffer, offset, tree_type, it->sha1);
free(buffer);
it->entry_count = i;
#if DEBUG
fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
it->entry_count, it->subtree_nr,
sha1_to_hex(it->sha1));
#endif
return i;
}
int cache_tree_update(struct cache_tree *it,
struct cache_entry **cache,
int entries,
int missing_ok,
int dryrun)
{
int i;
i = verify_cache(cache, entries);
if (i)
return i;
i = update_one(it, cache, entries, "", 0, missing_ok, dryrun);
if (i < 0)
return i;
return 0;
}
static void *write_one(struct cache_tree *it,
char *path,
int pathlen,
char *buffer,
unsigned long *size,
unsigned long *offset)
{
int i;
/* One "cache-tree" entry consists of the following:
* path (NUL terminated)
* entry_count, subtree_nr ("%d %d\n")
* tree-sha1 (missing if invalid)
* subtree_nr "cache-tree" entries for subtrees.
*/
if (*size < *offset + pathlen + 100) {
*size = alloc_nr(*offset + pathlen + 100);
buffer = xrealloc(buffer, *size);
}
*offset += sprintf(buffer + *offset, "%.*s%c%d %d\n",
pathlen, path, 0,
it->entry_count, it->subtree_nr);
#if DEBUG
if (0 <= it->entry_count)
fprintf(stderr, "cache-tree <%.*s> (%d ent, %d subtree) %s\n",
pathlen, path, it->entry_count, it->subtree_nr,
sha1_to_hex(it->sha1));
else
fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
pathlen, path, it->subtree_nr);
#endif
if (0 <= it->entry_count) {
hashcpy((unsigned char*)buffer + *offset, it->sha1);
*offset += 20;
}
for (i = 0; i < it->subtree_nr; i++) {
struct cache_tree_sub *down = it->down[i];
if (i) {
struct cache_tree_sub *prev = it->down[i-1];
if (subtree_name_cmp(down->name, down->namelen,
prev->name, prev->namelen) <= 0)
die("fatal - unsorted cache subtree");
}
buffer = write_one(down->cache_tree, down->name, down->namelen,
buffer, size, offset);
}
return buffer;
}
void *cache_tree_write(struct cache_tree *root, unsigned long *size_p)
{
char path[PATH_MAX];
unsigned long size = 8192;
char *buffer = xmalloc(size);
*size_p = 0;
path[0] = 0;
return write_one(root, path, 0, buffer, &size, size_p);
}
static struct cache_tree *read_one(const char **buffer, unsigned long *size_p)
{
const char *buf = *buffer;
unsigned long size = *size_p;
const char *cp;
char *ep;
struct cache_tree *it;
int i, subtree_nr;
it = NULL;
/* skip name, but make sure name exists */
while (size && *buf) {
size--;
buf++;
}
if (!size)
goto free_return;
buf++; size--;
it = cache_tree();
cp = buf;
it->entry_count = strtol(cp, &ep, 10);
if (cp == ep)
goto free_return;
cp = ep;
subtree_nr = strtol(cp, &ep, 10);
if (cp == ep)
goto free_return;
while (size && *buf && *buf != '\n') {
size--;
buf++;
}
if (!size)
goto free_return;
buf++; size--;
if (0 <= it->entry_count) {
if (size < 20)
goto free_return;
hashcpy(it->sha1, (unsigned char*)buf);
buf += 20;
size -= 20;
}
#if DEBUG
if (0 <= it->entry_count)
fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
*buffer, it->entry_count, subtree_nr,
sha1_to_hex(it->sha1));
else
fprintf(stderr, "cache-tree <%s> (%d subtrees) invalid\n",
*buffer, subtree_nr);
#endif
/*
* Just a heuristic -- we do not add directories that often but
* we do not want to have to extend it immediately when we do,
* hence +2.
*/
it->subtree_alloc = subtree_nr + 2;
it->down = xcalloc(it->subtree_alloc, sizeof(struct cache_tree_sub *));
for (i = 0; i < subtree_nr; i++) {
/* read each subtree */
struct cache_tree *sub;
struct cache_tree_sub *subtree;
const char *name = buf;
sub = read_one(&buf, &size);
if (!sub)
goto free_return;
subtree = cache_tree_sub(it, name);
subtree->cache_tree = sub;
}
if (subtree_nr != it->subtree_nr)
die("cache-tree: internal error");
*buffer = buf;
*size_p = size;
return it;
free_return:
cache_tree_free(&it);
return NULL;
}
struct cache_tree *cache_tree_read(const char *buffer, unsigned long size)
{
if (buffer[0])
return NULL; /* not the whole tree */
return read_one(&buffer, &size);
}
struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
{
while (*path) {
const char *slash;
struct cache_tree_sub *sub;
slash = strchr(path, '/');
if (!slash)
slash = path + strlen(path);
/* between path and slash is the name of the
* subtree to look for.
*/
sub = find_subtree(it, path, slash - path, 0);
if (!sub)
return NULL;
it = sub->cache_tree;
if (slash)
while (*slash && *slash == '/')
slash++;
if (!slash || !*slash)
return it; /* prefix ended with slashes */
path = slash;
}
return it;
}