git-commit-vandalism/tree.c
Linus Torvalds 4c068a9831 tree_entry(): new tree-walking helper function
This adds a "tree_entry()" function that combines the common operation of
doing a "tree_entry_extract()" + "update_tree_entry()".

It also has a simplified calling convention, designed for simple loops
that traverse over a whole tree: the arguments are pointers to the tree
descriptor and a name_entry structure to fill in, and it returns a boolean
"true" if there was an entry left to be gotten in the tree.

This allows tree traversal with

	struct tree_desc desc;
	struct name_entry entry;

	desc.buf = tree->buffer;
	desc.size = tree->size;
	while (tree_entry(&desc, &entry) {
		... use "entry.{path, sha1, mode, pathlen}" ...
	}

which is not only shorter than writing it out in full, it's hopefully less
error prone too.

[ It's actually a tad faster too - we don't need to recalculate the entry
  pathlength in both extract and update, but need to do it only once.
  Also, some callers can avoid doing a "strlen()" on the result, since
  it's returned as part of the name_entry structure.

  However, by now we're talking just 1% speedup on "git-rev-list --objects
  --all", and we're definitely at the point where tree walking is no
  longer the issue any more. ]

NOTE! Not everybody wants to use this new helper function, since some of
the tree walkers very much on purpose do the descriptor update separately
from the entry extraction. So the "extract + update" sequence still
remains as the core sequence, this is just a simplified interface.

We should probably add a silly two-line inline helper function for
initializing the descriptor from the "struct tree" too, just to cut down
on the noise from that common "desc" initializer.

Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
2006-05-30 23:03:01 -07:00

231 lines
5.0 KiB
C

#include "cache.h"
#include "tree.h"
#include "blob.h"
#include "commit.h"
#include "tag.h"
#include "tree-walk.h"
#include <stdlib.h>
const char *tree_type = "tree";
static int read_one_entry(const unsigned char *sha1, const char *base, int baselen, const char *pathname, unsigned mode, int stage)
{
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);
memcpy(ce->sha1, sha1, 20);
return add_cache_entry(ce, ADD_CACHE_OK_TO_ADD|ADD_CACHE_SKIP_DFCHECK);
}
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;
desc.buf = tree->buffer;
desc.size = 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;
newbase = xmalloc(baselen + 1 + entry.pathlen);
memcpy(newbase, base, baselen);
memcpy(newbase + baselen, entry.path, entry.pathlen);
newbase[baselen + entry.pathlen] = '/';
retval = read_tree_recursive(lookup_tree(entry.sha1),
newbase,
baselen + entry.pathlen + 1,
stage, match, fn);
free(newbase);
if (retval)
return -1;
continue;
}
}
return 0;
}
int read_tree(struct tree *tree, int stage, const char **match)
{
return read_tree_recursive(tree, "", 0, stage, match, read_one_entry);
}
struct tree *lookup_tree(const unsigned char *sha1)
{
struct object *obj = lookup_object(sha1);
if (!obj) {
struct tree *ret = xcalloc(1, sizeof(struct tree));
created_object(sha1, &ret->object);
ret->object.type = tree_type;
return ret;
}
if (!obj->type)
obj->type = tree_type;
if (obj->type != tree_type) {
error("Object %s is a %s, not a tree",
sha1_to_hex(sha1), obj->type);
return NULL;
}
return (struct tree *) obj;
}
static int 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.. */
desc.buf = item->buffer;
desc.size = item->size;
while (desc.size) {
n_refs++;
update_tree_entry(&desc);
}
/* Allocate object refs and walk it again.. */
i = 0;
refs = alloc_object_refs(n_refs);
desc.buf = item->buffer;
desc.size = item->size;
while (tree_entry(&desc, &entry)) {
struct object *obj;
if (S_ISDIR(entry.mode))
obj = &lookup_tree(entry.sha1)->object;
else
obj = &lookup_blob(entry.sha1)->object;
refs->ref[i++] = obj;
}
set_object_refs(&item->object, refs);
return 0;
}
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)
{
char type[20];
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 (strcmp(type, tree_type)) {
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 == tree_type)
return (struct tree *) obj;
else if (obj->type == commit_type)
obj = &(((struct commit *) obj)->tree->object);
else if (obj->type == tag_type)
obj = ((struct tag *) obj)->tagged;
else
return NULL;
if (!obj->parsed)
parse_object(obj->sha1);
} while (1);
}