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git/tree.c
Junio C Hamano af3785dc5a Optimize "diff --cached" performance.
The read_tree() function is called only from the call chain to
run "git diff --cached" (this includes the internal call made by
git-runstatus to run_diff_index()).  The function vacates stage
without any funky "merge" magic.  The caller then goes and
compares stage #1 entries from the tree with stage #0 entries
from the original index.

When adding the cache entries this way, it used the general
purpose add_cache_entry().  This function looks for an existing
entry to replace or if there is none to find where to insert the
new entry, resolves D/F conflict and all the other things.

For the purpose of reading entries into an empty stage, none of
that processing is needed.  We can instead append everything and
then sort the result at the end.

This commit changes read_tree() to first make sure that there is
no existing cache entries at specified stage, and if that is the
case, it runs add_cache_entry() with ADD_CACHE_JUST_APPEND flag
(new), and then sort the resulting cache using qsort().

This new flag tells add_cache_entry() to omit all the checks
such as "Does this path already exist?  Does adding this path
remove other existing entries because it turns a directory to a
file?" and instead append the given cache entry straight at the
end of the active cache.  The caller of course is expected to
sort the resulting cache at the end before using the result.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
2007-08-10 11:44:23 -07:00

301 lines
7.3 KiB
C

#include "cache.h"
#include "cache-tree.h"
#include "tree.h"
#include "blob.h"
#include "commit.h"
#include "tag.h"
#include "tree-walk.h"
const char *tree_type = "tree";
static int read_one_entry_opt(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage, int opt)
{
int len;
unsigned int size;
struct cache_entry *ce;
if (S_ISDIR(mode))
return READ_TREE_RECURSIVE;
len = strlen(pathname);
size = cache_entry_size(baselen + len);
ce = xcalloc(1, size);
ce->ce_mode = create_ce_mode(mode);
ce->ce_flags = create_ce_flags(baselen + len, stage);
memcpy(ce->name, base, baselen);
memcpy(ce->name + baselen, pathname, len+1);
hashcpy(ce->sha1, sha1);
return add_cache_entry(ce, opt);
}
static int read_one_entry(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage)
{
return read_one_entry_opt(sha1, base, baselen, pathname, mode, stage,
ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
}
/*
* This is used when the caller knows there is no existing entries at
* the stage that will conflict with the entry being added.
*/
static int read_one_entry_quick(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage)
{
return read_one_entry_opt(sha1, base, baselen, pathname, mode, stage,
ADD_CACHE_JUST_APPEND);
}
static int match_tree_entry(const char *base, int baselen, const char *path, unsigned int mode, const char **paths)
{
const char *match;
int pathlen;
if (!paths)
return 1;
pathlen = strlen(path);
while ((match = *paths++) != NULL) {
int matchlen = strlen(match);
if (baselen >= matchlen) {
/* If it doesn't match, move along... */
if (strncmp(base, match, matchlen))
continue;
/* The base is a subdirectory of a path which was specified. */
return 1;
}
/* Does the base match? */
if (strncmp(base, match, baselen))
continue;
match += baselen;
matchlen -= baselen;
if (pathlen > matchlen)
continue;
if (matchlen > pathlen) {
if (match[pathlen] != '/')
continue;
if (!S_ISDIR(mode))
continue;
}
if (strncmp(path, match, pathlen))
continue;
return 1;
}
return 0;
}
int read_tree_recursive(struct tree *tree,
const char *base, int baselen,
int stage, const char **match,
read_tree_fn_t fn)
{
struct tree_desc desc;
struct name_entry entry;
if (parse_tree(tree))
return -1;
init_tree_desc(&desc, tree->buffer, tree->size);
while (tree_entry(&desc, &entry)) {
if (!match_tree_entry(base, baselen, entry.path, entry.mode, match))
continue;
switch (fn(entry.sha1, base, baselen, entry.path, entry.mode, stage)) {
case 0:
continue;
case READ_TREE_RECURSIVE:
break;;
default:
return -1;
}
if (S_ISDIR(entry.mode)) {
int retval;
char *newbase;
unsigned int pathlen = tree_entry_len(entry.path, entry.sha1);
newbase = xmalloc(baselen + 1 + pathlen);
memcpy(newbase, base, baselen);
memcpy(newbase + baselen, entry.path, pathlen);
newbase[baselen + pathlen] = '/';
retval = read_tree_recursive(lookup_tree(entry.sha1),
newbase,
baselen + pathlen + 1,
stage, match, fn);
free(newbase);
if (retval)
return -1;
continue;
}
}
return 0;
}
static int cmp_cache_name_compare(const void *a_, const void *b_)
{
const struct cache_entry *ce1, *ce2;
ce1 = *((const struct cache_entry **)a_);
ce2 = *((const struct cache_entry **)b_);
return cache_name_compare(ce1->name, ntohs(ce1->ce_flags),
ce2->name, ntohs(ce2->ce_flags));
}
int read_tree(struct tree *tree, int stage, const char **match)
{
read_tree_fn_t fn = NULL;
int i, err;
/*
* Currently the only existing callers of this function all
* call it with stage=1 and after making sure there is nothing
* at that stage; we could always use read_one_entry_quick().
*
* But when we decide to straighten out git-read-tree not to
* use unpack_trees() in some cases, this will probably start
* to matter.
*/
/*
* See if we have cache entry at the stage. If so,
* do it the original slow way, otherwise, append and then
* sort at the end.
*/
for (i = 0; !fn && i < active_nr; i++) {
struct cache_entry *ce = active_cache[i];
if (ce_stage(ce) == stage)
fn = read_one_entry;
}
if (!fn)
fn = read_one_entry_quick;
err = read_tree_recursive(tree, "", 0, stage, match, fn);
if (fn == read_one_entry || err)
return err;
/*
* Sort the cache entry -- we need to nuke the cache tree, though.
*/
cache_tree_free(&active_cache_tree);
qsort(active_cache, active_nr, sizeof(active_cache[0]),
cmp_cache_name_compare);
return 0;
}
struct tree *lookup_tree(const unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);
if (!obj)
return create_object(sha1, OBJ_TREE, alloc_tree_node());
if (!obj->type)
obj->type = OBJ_TREE;
if (obj->type != OBJ_TREE) {
error("Object %s is a %s, not a tree",
sha1_to_hex(sha1), typename(obj->type));
return NULL;
}
return (struct tree *) obj;
}
/*
* NOTE! Tree refs to external git repositories
* (ie gitlinks) do not count as real references.
*
* You don't have to have those repositories
* available at all, much less have the objects
* accessible from the current repository.
*/
static void track_tree_refs(struct tree *item)
{
int n_refs = 0, i;
struct object_refs *refs;
struct tree_desc desc;
struct name_entry entry;
/* Count how many entries there are.. */
init_tree_desc(&desc, item->buffer, item->size);
while (tree_entry(&desc, &entry)) {
if (S_ISGITLINK(entry.mode))
continue;
n_refs++;
}
/* Allocate object refs and walk it again.. */
i = 0;
refs = alloc_object_refs(n_refs);
init_tree_desc(&desc, item->buffer, item->size);
while (tree_entry(&desc, &entry)) {
struct object *obj;
if (S_ISGITLINK(entry.mode))
continue;
if (S_ISDIR(entry.mode))
obj = &lookup_tree(entry.sha1)->object;
else if (S_ISREG(entry.mode) || S_ISLNK(entry.mode))
obj = &lookup_blob(entry.sha1)->object;
else {
warning("in tree %s: entry %s has bad mode %.6o\n",
sha1_to_hex(item->object.sha1), entry.path, entry.mode);
obj = lookup_unknown_object(entry.sha1);
}
refs->ref[i++] = obj;
}
set_object_refs(&item->object, refs);
}
int parse_tree_buffer(struct tree *item, void *buffer, unsigned long size)
{
if (item->object.parsed)
return 0;
item->object.parsed = 1;
item->buffer = buffer;
item->size = size;
if (track_object_refs)
track_tree_refs(item);
return 0;
}
int parse_tree(struct tree *item)
{
enum object_type type;
void *buffer;
unsigned long size;
if (item->object.parsed)
return 0;
buffer = read_sha1_file(item->object.sha1, &type, &size);
if (!buffer)
return error("Could not read %s",
sha1_to_hex(item->object.sha1));
if (type != OBJ_TREE) {
free(buffer);
return error("Object %s not a tree",
sha1_to_hex(item->object.sha1));
}
return parse_tree_buffer(item, buffer, size);
}
struct tree *parse_tree_indirect(const unsigned char *sha1)
{
struct object *obj = parse_object(sha1);
do {
if (!obj)
return NULL;
if (obj->type == OBJ_TREE)
return (struct tree *) obj;
else if (obj->type == OBJ_COMMIT)
obj = &(((struct commit *) obj)->tree->object);
else if (obj->type == OBJ_TAG)
obj = ((struct tag *) obj)->tagged;
else
return NULL;
if (!obj->parsed)
parse_object(obj->sha1);
} while (1);
}