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git/vcs-svn/repo_tree.c
Jonathan Nieder 3c93983875 vcs-svn: fix intermittent repo_tree corruption
Pointers to directory entries do not remain valid after a call to
dent_insert.

Noticed in the course of importing a small Subversion repository
(~1000 revs); after setting up a dirent for a certain path as a
placeholder, by luck dent_insert would trigger a realloc that
shifted around addresses, resulting in an import with that file
replaced by a directory.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2010-12-07 16:04:02 -08:00

329 lines
8.2 KiB
C

/*
* Licensed under a two-clause BSD-style license.
* See LICENSE for details.
*/
#include "git-compat-util.h"
#include "string_pool.h"
#include "repo_tree.h"
#include "obj_pool.h"
#include "fast_export.h"
#include "trp.h"
struct repo_dirent {
uint32_t name_offset;
struct trp_node children;
uint32_t mode;
uint32_t content_offset;
};
struct repo_dir {
struct trp_root entries;
};
struct repo_commit {
uint32_t root_dir_offset;
};
/* Memory pools for commit, dir and dirent */
obj_pool_gen(commit, struct repo_commit, 4096)
obj_pool_gen(dir, struct repo_dir, 4096)
obj_pool_gen(dent, struct repo_dirent, 4096)
static uint32_t active_commit;
static uint32_t mark;
static int repo_dirent_name_cmp(const void *a, const void *b);
/* Treap for directory entries */
trp_gen(static, dent_, struct repo_dirent, children, dent, repo_dirent_name_cmp);
uint32_t next_blob_mark(void)
{
return mark++;
}
static struct repo_dir *repo_commit_root_dir(struct repo_commit *commit)
{
return dir_pointer(commit->root_dir_offset);
}
static struct repo_dirent *repo_first_dirent(struct repo_dir *dir)
{
return dent_first(&dir->entries);
}
static int repo_dirent_name_cmp(const void *a, const void *b)
{
const struct repo_dirent *dent1 = a, *dent2 = b;
uint32_t a_offset = dent1->name_offset;
uint32_t b_offset = dent2->name_offset;
return (a_offset > b_offset) - (a_offset < b_offset);
}
static int repo_dirent_is_dir(struct repo_dirent *dent)
{
return dent != NULL && dent->mode == REPO_MODE_DIR;
}
static struct repo_dir *repo_dir_from_dirent(struct repo_dirent *dent)
{
if (!repo_dirent_is_dir(dent))
return NULL;
return dir_pointer(dent->content_offset);
}
static struct repo_dir *repo_clone_dir(struct repo_dir *orig_dir)
{
uint32_t orig_o, new_o;
orig_o = dir_offset(orig_dir);
if (orig_o >= dir_pool.committed)
return orig_dir;
new_o = dir_alloc(1);
orig_dir = dir_pointer(orig_o);
*dir_pointer(new_o) = *orig_dir;
return dir_pointer(new_o);
}
static struct repo_dirent *repo_read_dirent(uint32_t revision, uint32_t *path)
{
uint32_t name = 0;
struct repo_dirent *key = dent_pointer(dent_alloc(1));
struct repo_dir *dir = NULL;
struct repo_dirent *dent = NULL;
dir = repo_commit_root_dir(commit_pointer(revision));
while (~(name = *path++)) {
key->name_offset = name;
dent = dent_search(&dir->entries, key);
if (dent == NULL || !repo_dirent_is_dir(dent))
break;
dir = repo_dir_from_dirent(dent);
}
dent_free(1);
return dent;
}
static void repo_write_dirent(uint32_t *path, uint32_t mode,
uint32_t content_offset, uint32_t del)
{
uint32_t name, revision, dir_o = ~0, parent_dir_o = ~0;
struct repo_dir *dir;
struct repo_dirent *key;
struct repo_dirent *dent = NULL;
revision = active_commit;
dir = repo_commit_root_dir(commit_pointer(revision));
dir = repo_clone_dir(dir);
commit_pointer(revision)->root_dir_offset = dir_offset(dir);
while (~(name = *path++)) {
parent_dir_o = dir_offset(dir);
key = dent_pointer(dent_alloc(1));
key->name_offset = name;
dent = dent_search(&dir->entries, key);
if (dent == NULL)
dent = key;
else
dent_free(1);
if (dent == key) {
dent->mode = REPO_MODE_DIR;
dent->content_offset = 0;
dent = dent_insert(&dir->entries, dent);
}
if (dent_offset(dent) < dent_pool.committed) {
dir_o = repo_dirent_is_dir(dent) ?
dent->content_offset : ~0;
dent_remove(&dir->entries, dent);
dent = dent_pointer(dent_alloc(1));
dent->name_offset = name;
dent->mode = REPO_MODE_DIR;
dent->content_offset = dir_o;
dent = dent_insert(&dir->entries, dent);
}
dir = repo_dir_from_dirent(dent);
dir = repo_clone_dir(dir);
dent->content_offset = dir_offset(dir);
}
if (dent == NULL)
return;
dent->mode = mode;
dent->content_offset = content_offset;
if (del && ~parent_dir_o)
dent_remove(&dir_pointer(parent_dir_o)->entries, dent);
}
uint32_t repo_copy(uint32_t revision, uint32_t *src, uint32_t *dst)
{
uint32_t mode = 0, content_offset = 0;
struct repo_dirent *src_dent;
src_dent = repo_read_dirent(revision, src);
if (src_dent != NULL) {
mode = src_dent->mode;
content_offset = src_dent->content_offset;
repo_write_dirent(dst, mode, content_offset, 0);
}
return mode;
}
void repo_add(uint32_t *path, uint32_t mode, uint32_t blob_mark)
{
repo_write_dirent(path, mode, blob_mark, 0);
}
uint32_t repo_replace(uint32_t *path, uint32_t blob_mark)
{
uint32_t mode = 0;
struct repo_dirent *src_dent;
src_dent = repo_read_dirent(active_commit, path);
if (src_dent != NULL) {
mode = src_dent->mode;
repo_write_dirent(path, mode, blob_mark, 0);
}
return mode;
}
void repo_modify(uint32_t *path, uint32_t mode, uint32_t blob_mark)
{
struct repo_dirent *src_dent;
src_dent = repo_read_dirent(active_commit, path);
if (src_dent != NULL && blob_mark == 0)
blob_mark = src_dent->content_offset;
repo_write_dirent(path, mode, blob_mark, 0);
}
void repo_delete(uint32_t *path)
{
repo_write_dirent(path, 0, 0, 1);
}
static void repo_git_add_r(uint32_t depth, uint32_t *path, struct repo_dir *dir);
static void repo_git_add(uint32_t depth, uint32_t *path, struct repo_dirent *dent)
{
if (repo_dirent_is_dir(dent))
repo_git_add_r(depth, path, repo_dir_from_dirent(dent));
else
fast_export_modify(depth, path,
dent->mode, dent->content_offset);
}
static void repo_git_add_r(uint32_t depth, uint32_t *path, struct repo_dir *dir)
{
struct repo_dirent *de = repo_first_dirent(dir);
while (de) {
path[depth] = de->name_offset;
repo_git_add(depth + 1, path, de);
de = dent_next(&dir->entries, de);
}
}
static void repo_diff_r(uint32_t depth, uint32_t *path, struct repo_dir *dir1,
struct repo_dir *dir2)
{
struct repo_dirent *de1, *de2;
de1 = repo_first_dirent(dir1);
de2 = repo_first_dirent(dir2);
while (de1 && de2) {
if (de1->name_offset < de2->name_offset) {
path[depth] = de1->name_offset;
fast_export_delete(depth + 1, path);
de1 = dent_next(&dir1->entries, de1);
continue;
}
if (de1->name_offset > de2->name_offset) {
path[depth] = de2->name_offset;
repo_git_add(depth + 1, path, de2);
de2 = dent_next(&dir2->entries, de2);
continue;
}
path[depth] = de1->name_offset;
if (de1->mode == de2->mode &&
de1->content_offset == de2->content_offset) {
; /* No change. */
} else if (repo_dirent_is_dir(de1) && repo_dirent_is_dir(de2)) {
repo_diff_r(depth + 1, path,
repo_dir_from_dirent(de1),
repo_dir_from_dirent(de2));
} else if (!repo_dirent_is_dir(de1) && !repo_dirent_is_dir(de2)) {
repo_git_add(depth + 1, path, de2);
} else {
fast_export_delete(depth + 1, path);
repo_git_add(depth + 1, path, de2);
}
de1 = dent_next(&dir1->entries, de1);
de2 = dent_next(&dir2->entries, de2);
}
while (de1) {
path[depth] = de1->name_offset;
fast_export_delete(depth + 1, path);
de1 = dent_next(&dir1->entries, de1);
}
while (de2) {
path[depth] = de2->name_offset;
repo_git_add(depth + 1, path, de2);
de2 = dent_next(&dir2->entries, de2);
}
}
static uint32_t path_stack[REPO_MAX_PATH_DEPTH];
void repo_diff(uint32_t r1, uint32_t r2)
{
repo_diff_r(0,
path_stack,
repo_commit_root_dir(commit_pointer(r1)),
repo_commit_root_dir(commit_pointer(r2)));
}
void repo_commit(uint32_t revision, uint32_t author, char *log, uint32_t uuid,
uint32_t url, unsigned long timestamp)
{
fast_export_commit(revision, author, log, uuid, url, timestamp);
dent_commit();
dir_commit();
active_commit = commit_alloc(1);
commit_pointer(active_commit)->root_dir_offset =
commit_pointer(active_commit - 1)->root_dir_offset;
}
static void mark_init(void)
{
uint32_t i;
mark = 0;
for (i = 0; i < dent_pool.size; i++)
if (!repo_dirent_is_dir(dent_pointer(i)) &&
dent_pointer(i)->content_offset > mark)
mark = dent_pointer(i)->content_offset;
mark++;
}
void repo_init(void)
{
mark_init();
if (commit_pool.size == 0) {
/* Create empty tree for commit 0. */
commit_alloc(1);
commit_pointer(0)->root_dir_offset = dir_alloc(1);
dir_pointer(0)->entries.trp_root = ~0;
dir_commit();
}
/* Preallocate next commit, ready for changes. */
active_commit = commit_alloc(1);
commit_pointer(active_commit)->root_dir_offset =
commit_pointer(active_commit - 1)->root_dir_offset;
}
void repo_reset(void)
{
pool_reset();
commit_reset();
dir_reset();
dent_reset();
}