git/cache-tree.c
Jeff King 4a7e27e957 convert "oidcmp() == 0" to oideq()
Using the more restrictive oideq() should, in the long run,
give the compiler more opportunities to optimize these
callsites. For now, this conversion should be a complete
noop with respect to the generated code.

The result is also perhaps a little more readable, as it
avoids the "zero is equal" idiom. Since it's so prevalent in
C, I think seasoned programmers tend not to even notice it
anymore, but it can sometimes make for awkward double
negations (e.g., we can drop a few !!oidcmp() instances
here).

This patch was generated almost entirely by the included
coccinelle patch. This mechanical conversion should be
completely safe, because we check explicitly for cases where
oidcmp() is compared to 0, which is what oideq() is doing
under the hood. Note that we don't have to catch "!oidcmp()"
separately; coccinelle's standard isomorphisms make sure the
two are treated equivalently.

I say "almost" because I did hand-edit the coccinelle output
to fix up a few style violations (it mostly keeps the
original formatting, but sometimes unwraps long lines).

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-29 11:32:49 -07:00

721 lines
17 KiB
C

#include "cache.h"
#include "lockfile.h"
#include "tree.h"
#include "tree-walk.h"
#include "cache-tree.h"
#include "object-store.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[i]);
}
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 - lo) / 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;
ALLOC_GROW(it->down, it->subtree_nr + 1, it->subtree_alloc);
it->subtree_nr++;
FLEX_ALLOC_MEM(down, name, path, pathlen);
down->cache_tree = NULL;
down->namelen = pathlen;
if (pos < it->subtree_nr)
MOVE_ARRAY(it->down + pos + 1, it->down + pos,
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);
}
static int do_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 0;
slash = strchrnul(path, '/');
namelen = slash - path;
it->entry_count = -1;
if (!*slash) {
int pos;
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
*/
MOVE_ARRAY(it->down + pos, it->down + pos + 1,
it->subtree_nr - pos - 1);
it->subtree_nr--;
}
return 1;
}
down = find_subtree(it, path, namelen, 0);
if (down)
do_invalidate_path(down->cache_tree, slash + 1);
return 1;
}
void cache_tree_invalidate_path(struct index_state *istate, const char *path)
{
if (do_invalidate_path(istate->cache_tree, path))
istate->cache_changed |= CACHE_TREE_CHANGED;
}
static int verify_cache(struct cache_entry **cache,
int entries, int flags)
{
int i, funny;
int silent = flags & WRITE_TREE_SILENT;
/* Verify that the tree is merged */
funny = 0;
for (i = 0; i < entries; i++) {
const struct cache_entry *ce = cache[i];
if (ce_stage(ce)) {
if (silent)
return -1;
if (10 < ++funny) {
fprintf(stderr, "...\n");
break;
}
fprintf(stderr, "%s: unmerged (%s)\n",
ce->name, oid_to_hex(&ce->oid));
}
}
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->oid.hash))
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 *skip_count,
int flags)
{
struct strbuf buffer;
int missing_ok = flags & WRITE_TREE_MISSING_OK;
int dryrun = flags & WRITE_TREE_DRY_RUN;
int repair = flags & WRITE_TREE_REPAIR;
int to_invalidate = 0;
int i;
assert(!(dryrun && repair));
*skip_count = 0;
if (0 <= it->entry_count && has_sha1_file(it->oid.hash))
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.
*/
i = 0;
while (i < entries) {
const struct cache_entry *ce = cache[i];
struct cache_tree_sub *sub;
const char *path, *slash;
int pathlen, sublen, subcnt, subskip;
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) {
i++;
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,
&subskip,
flags);
if (subcnt < 0)
return subcnt;
if (!subcnt)
die("index cache-tree records empty sub-tree");
i += subcnt;
sub->count = subcnt; /* to be used in the next loop */
*skip_count += subskip;
sub->used = 1;
}
discard_unused_subtrees(it);
/*
* Then write out the tree object for this level.
*/
strbuf_init(&buffer, 8192);
i = 0;
while (i < entries) {
const struct cache_entry *ce = cache[i];
struct cache_tree_sub *sub = NULL;
const char *path, *slash;
int pathlen, entlen;
const struct object_id *oid;
unsigned mode;
int expected_missing = 0;
int contains_ita = 0;
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->count;
oid = &sub->cache_tree->oid;
mode = S_IFDIR;
contains_ita = sub->cache_tree->entry_count < 0;
if (contains_ita) {
to_invalidate = 1;
expected_missing = 1;
}
}
else {
oid = &ce->oid;
mode = ce->ce_mode;
entlen = pathlen - baselen;
i++;
}
if (is_null_oid(oid) ||
(mode != S_IFGITLINK && !missing_ok && !has_object_file(oid))) {
strbuf_release(&buffer);
if (expected_missing)
return -1;
return error("invalid object %06o %s for '%.*s'",
mode, oid_to_hex(oid), entlen+baselen, path);
}
/*
* CE_REMOVE entries are removed before the index is
* written to disk. Skip them to remain consistent
* with the future on-disk index.
*/
if (ce->ce_flags & CE_REMOVE) {
*skip_count = *skip_count + 1;
continue;
}
/*
* CE_INTENT_TO_ADD entries exist on on-disk index but
* they are not part of generated trees. Invalidate up
* to root to force cache-tree users to read elsewhere.
*/
if (!sub && ce_intent_to_add(ce)) {
to_invalidate = 1;
continue;
}
/*
* "sub" can be an empty tree if all subentries are i-t-a.
*/
if (contains_ita && is_empty_tree_oid(oid))
continue;
strbuf_grow(&buffer, entlen + 100);
strbuf_addf(&buffer, "%o %.*s%c", mode, entlen, path + baselen, '\0');
strbuf_add(&buffer, oid->hash, the_hash_algo->rawsz);
#if DEBUG
fprintf(stderr, "cache-tree update-one %o %.*s\n",
mode, entlen, path + baselen);
#endif
}
if (repair) {
struct object_id oid;
hash_object_file(buffer.buf, buffer.len, tree_type, &oid);
if (has_object_file(&oid))
oidcpy(&it->oid, &oid);
else
to_invalidate = 1;
} else if (dryrun) {
hash_object_file(buffer.buf, buffer.len, tree_type, &it->oid);
} else if (write_object_file(buffer.buf, buffer.len, tree_type,
&it->oid)) {
strbuf_release(&buffer);
return -1;
}
strbuf_release(&buffer);
it->entry_count = to_invalidate ? -1 : i - *skip_count;
#if DEBUG
fprintf(stderr, "cache-tree update-one (%d ent, %d subtree) %s\n",
it->entry_count, it->subtree_nr,
oid_to_hex(&it->oid));
#endif
return i;
}
int cache_tree_update(struct index_state *istate, int flags)
{
struct cache_tree *it = istate->cache_tree;
struct cache_entry **cache = istate->cache;
int entries = istate->cache_nr;
int skip, i = verify_cache(cache, entries, flags);
if (i)
return i;
i = update_one(it, cache, entries, "", 0, &skip, flags);
if (i < 0)
return i;
istate->cache_changed |= CACHE_TREE_CHANGED;
return 0;
}
static void write_one(struct strbuf *buffer, struct cache_tree *it,
const char *path, int pathlen)
{
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.
*/
strbuf_grow(buffer, pathlen + 100);
strbuf_add(buffer, path, pathlen);
strbuf_addf(buffer, "%c%d %d\n", 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,
oid_to_hex(&it->oid));
else
fprintf(stderr, "cache-tree <%.*s> (%d subtree) invalid\n",
pathlen, path, it->subtree_nr);
#endif
if (0 <= it->entry_count) {
strbuf_add(buffer, it->oid.hash, the_hash_algo->rawsz);
}
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");
}
write_one(buffer, down->cache_tree, down->name, down->namelen);
}
}
void cache_tree_write(struct strbuf *sb, struct cache_tree *root)
{
write_one(sb, root, "", 0);
}
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;
const unsigned rawsz = the_hash_algo->rawsz;
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 < rawsz)
goto free_return;
oidread(&it->oid, (const unsigned char *)buf);
buf += rawsz;
size -= rawsz;
}
#if DEBUG
if (0 <= it->entry_count)
fprintf(stderr, "cache-tree <%s> (%d ent, %d subtree) %s\n",
*buffer, it->entry_count, subtree_nr,
oid_to_hex(&it->oid));
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);
}
static struct cache_tree *cache_tree_find(struct cache_tree *it, const char *path)
{
if (!it)
return NULL;
while (*path) {
const char *slash;
struct cache_tree_sub *sub;
slash = strchrnul(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;
path = slash;
while (*path == '/')
path++;
}
return it;
}
int write_index_as_tree(struct object_id *oid, struct index_state *index_state, const char *index_path, int flags, const char *prefix)
{
int entries, was_valid;
struct lock_file lock_file = LOCK_INIT;
int ret = 0;
hold_lock_file_for_update(&lock_file, index_path, LOCK_DIE_ON_ERROR);
entries = read_index_from(index_state, index_path, get_git_dir());
if (entries < 0) {
ret = WRITE_TREE_UNREADABLE_INDEX;
goto out;
}
if (flags & WRITE_TREE_IGNORE_CACHE_TREE)
cache_tree_free(&index_state->cache_tree);
if (!index_state->cache_tree)
index_state->cache_tree = cache_tree();
was_valid = cache_tree_fully_valid(index_state->cache_tree);
if (!was_valid) {
if (cache_tree_update(index_state, flags) < 0) {
ret = WRITE_TREE_UNMERGED_INDEX;
goto out;
}
write_locked_index(index_state, &lock_file, COMMIT_LOCK);
/* Not being able to write is fine -- we are only interested
* in updating the cache-tree part, and if the next caller
* ends up using the old index with unupdated cache-tree part
* it misses the work we did here, but that is just a
* performance penalty and not a big deal.
*/
}
if (prefix) {
struct cache_tree *subtree;
subtree = cache_tree_find(index_state->cache_tree, prefix);
if (!subtree) {
ret = WRITE_TREE_PREFIX_ERROR;
goto out;
}
oidcpy(oid, &subtree->oid);
}
else
oidcpy(oid, &index_state->cache_tree->oid);
out:
rollback_lock_file(&lock_file);
return ret;
}
static void prime_cache_tree_rec(struct cache_tree *it, struct tree *tree)
{
struct tree_desc desc;
struct name_entry entry;
int cnt;
oidcpy(&it->oid, &tree->object.oid);
init_tree_desc(&desc, tree->buffer, tree->size);
cnt = 0;
while (tree_entry(&desc, &entry)) {
if (!S_ISDIR(entry.mode))
cnt++;
else {
struct cache_tree_sub *sub;
struct tree *subtree = lookup_tree(the_repository,
entry.oid);
if (!subtree->object.parsed)
parse_tree(subtree);
sub = cache_tree_sub(it, entry.path);
sub->cache_tree = cache_tree();
prime_cache_tree_rec(sub->cache_tree, subtree);
cnt += sub->cache_tree->entry_count;
}
}
it->entry_count = cnt;
}
void prime_cache_tree(struct index_state *istate, struct tree *tree)
{
cache_tree_free(&istate->cache_tree);
istate->cache_tree = cache_tree();
prime_cache_tree_rec(istate->cache_tree, tree);
istate->cache_changed |= CACHE_TREE_CHANGED;
}
/*
* find the cache_tree that corresponds to the current level without
* exploding the full path into textual form. The root of the
* cache tree is given as "root", and our current level is "info".
* (1) When at root level, info->prev is NULL, so it is "root" itself.
* (2) Otherwise, find the cache_tree that corresponds to one level
* above us, and find ourselves in there.
*/
static struct cache_tree *find_cache_tree_from_traversal(struct cache_tree *root,
struct traverse_info *info)
{
struct cache_tree *our_parent;
if (!info->prev)
return root;
our_parent = find_cache_tree_from_traversal(root, info->prev);
return cache_tree_find(our_parent, info->name.path);
}
int cache_tree_matches_traversal(struct cache_tree *root,
struct name_entry *ent,
struct traverse_info *info)
{
struct cache_tree *it;
it = find_cache_tree_from_traversal(root, info);
it = cache_tree_find(it, ent->path);
if (it && it->entry_count > 0 && oideq(ent->oid, &it->oid))
return it->entry_count;
return 0;
}