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-rw-r--r--tmp-objdir.c316
1 files changed, 316 insertions, 0 deletions
diff --git a/tmp-objdir.c b/tmp-objdir.c
new file mode 100644
index 0000000..2a2012e
--- /dev/null
+++ b/tmp-objdir.c
@@ -0,0 +1,316 @@
+#include "cache.h"
+#include "tmp-objdir.h"
+#include "chdir-notify.h"
+#include "dir.h"
+#include "sigchain.h"
+#include "string-list.h"
+#include "strbuf.h"
+#include "strvec.h"
+#include "quote.h"
+#include "object-store.h"
+
+struct tmp_objdir {
+ struct strbuf path;
+ struct strvec env;
+ struct object_directory *prev_odb;
+ int will_destroy;
+};
+
+/*
+ * Allow only one tmp_objdir at a time in a running process, which simplifies
+ * our atexit cleanup routines. It's doubtful callers will ever need
+ * more than one, and we can expand later if so. You can have many such
+ * tmp_objdirs simultaneously in many processes, of course.
+ */
+static struct tmp_objdir *the_tmp_objdir;
+
+static void tmp_objdir_free(struct tmp_objdir *t)
+{
+ strbuf_release(&t->path);
+ strvec_clear(&t->env);
+ free(t);
+}
+
+int tmp_objdir_destroy(struct tmp_objdir *t)
+{
+ int err;
+
+ if (!t)
+ return 0;
+
+ if (t == the_tmp_objdir)
+ the_tmp_objdir = NULL;
+
+ if (t->prev_odb)
+ restore_primary_odb(t->prev_odb, t->path.buf);
+
+ err = remove_dir_recursively(&t->path, 0);
+
+ tmp_objdir_free(t);
+
+ return err;
+}
+
+static void remove_tmp_objdir(void)
+{
+ tmp_objdir_destroy(the_tmp_objdir);
+}
+
+void tmp_objdir_discard_objects(struct tmp_objdir *t)
+{
+ remove_dir_recursively(&t->path, REMOVE_DIR_KEEP_TOPLEVEL);
+}
+
+/*
+ * These env_* functions are for setting up the child environment; the
+ * "replace" variant overrides the value of any existing variable with that
+ * "key". The "append" variant puts our new value at the end of a list,
+ * separated by PATH_SEP (which is what separate values in
+ * GIT_ALTERNATE_OBJECT_DIRECTORIES).
+ */
+static void env_append(struct strvec *env, const char *key, const char *val)
+{
+ struct strbuf quoted = STRBUF_INIT;
+ const char *old;
+
+ /*
+ * Avoid quoting if it's not necessary, for maximum compatibility
+ * with older parsers which don't understand the quoting.
+ */
+ if (*val == '"' || strchr(val, PATH_SEP)) {
+ strbuf_addch(&quoted, '"');
+ quote_c_style(val, &quoted, NULL, 1);
+ strbuf_addch(&quoted, '"');
+ val = quoted.buf;
+ }
+
+ old = getenv(key);
+ if (!old)
+ strvec_pushf(env, "%s=%s", key, val);
+ else
+ strvec_pushf(env, "%s=%s%c%s", key, old, PATH_SEP, val);
+
+ strbuf_release(&quoted);
+}
+
+static void env_replace(struct strvec *env, const char *key, const char *val)
+{
+ strvec_pushf(env, "%s=%s", key, val);
+}
+
+static int setup_tmp_objdir(const char *root)
+{
+ char *path;
+ int ret = 0;
+
+ path = xstrfmt("%s/pack", root);
+ ret = mkdir(path, 0777);
+ free(path);
+
+ return ret;
+}
+
+struct tmp_objdir *tmp_objdir_create(const char *prefix)
+{
+ static int installed_handlers;
+ struct tmp_objdir *t;
+
+ if (the_tmp_objdir)
+ BUG("only one tmp_objdir can be used at a time");
+
+ t = xcalloc(1, sizeof(*t));
+ strbuf_init(&t->path, 0);
+ strvec_init(&t->env);
+
+ /*
+ * Use a string starting with tmp_ so that the builtin/prune.c code
+ * can recognize any stale objdirs left behind by a crash and delete
+ * them.
+ */
+ strbuf_addf(&t->path, "%s/tmp_objdir-%s-XXXXXX", get_object_directory(), prefix);
+
+ if (!mkdtemp(t->path.buf)) {
+ /* free, not destroy, as we never touched the filesystem */
+ tmp_objdir_free(t);
+ return NULL;
+ }
+
+ the_tmp_objdir = t;
+ if (!installed_handlers) {
+ atexit(remove_tmp_objdir);
+ installed_handlers++;
+ }
+
+ if (setup_tmp_objdir(t->path.buf)) {
+ tmp_objdir_destroy(t);
+ return NULL;
+ }
+
+ env_append(&t->env, ALTERNATE_DB_ENVIRONMENT,
+ absolute_path(get_object_directory()));
+ env_replace(&t->env, DB_ENVIRONMENT, absolute_path(t->path.buf));
+ env_replace(&t->env, GIT_QUARANTINE_ENVIRONMENT,
+ absolute_path(t->path.buf));
+
+ return t;
+}
+
+/*
+ * Make sure we copy packfiles and their associated metafiles in the correct
+ * order. All of these ends_with checks are slightly expensive to do in
+ * the midst of a sorting routine, but in practice it shouldn't matter.
+ * We will have a relatively small number of packfiles to order, and loose
+ * objects exit early in the first line.
+ */
+static int pack_copy_priority(const char *name)
+{
+ if (!starts_with(name, "pack"))
+ return 0;
+ if (ends_with(name, ".keep"))
+ return 1;
+ if (ends_with(name, ".pack"))
+ return 2;
+ if (ends_with(name, ".rev"))
+ return 3;
+ if (ends_with(name, ".idx"))
+ return 4;
+ return 5;
+}
+
+static int pack_copy_cmp(const char *a, const char *b)
+{
+ return pack_copy_priority(a) - pack_copy_priority(b);
+}
+
+static int read_dir_paths(struct string_list *out, const char *path)
+{
+ DIR *dh;
+ struct dirent *de;
+
+ dh = opendir(path);
+ if (!dh)
+ return -1;
+
+ while ((de = readdir(dh)))
+ if (de->d_name[0] != '.')
+ string_list_append(out, de->d_name);
+
+ closedir(dh);
+ return 0;
+}
+
+static int migrate_paths(struct strbuf *src, struct strbuf *dst);
+
+static int migrate_one(struct strbuf *src, struct strbuf *dst)
+{
+ struct stat st;
+
+ if (stat(src->buf, &st) < 0)
+ return -1;
+ if (S_ISDIR(st.st_mode)) {
+ if (!mkdir(dst->buf, 0777)) {
+ if (adjust_shared_perm(dst->buf))
+ return -1;
+ } else if (errno != EEXIST)
+ return -1;
+ return migrate_paths(src, dst);
+ }
+ return finalize_object_file(src->buf, dst->buf);
+}
+
+static int migrate_paths(struct strbuf *src, struct strbuf *dst)
+{
+ size_t src_len = src->len, dst_len = dst->len;
+ struct string_list paths = STRING_LIST_INIT_DUP;
+ int i;
+ int ret = 0;
+
+ if (read_dir_paths(&paths, src->buf) < 0)
+ return -1;
+ paths.cmp = pack_copy_cmp;
+ string_list_sort(&paths);
+
+ for (i = 0; i < paths.nr; i++) {
+ const char *name = paths.items[i].string;
+
+ strbuf_addf(src, "/%s", name);
+ strbuf_addf(dst, "/%s", name);
+
+ ret |= migrate_one(src, dst);
+
+ strbuf_setlen(src, src_len);
+ strbuf_setlen(dst, dst_len);
+ }
+
+ string_list_clear(&paths, 0);
+ return ret;
+}
+
+int tmp_objdir_migrate(struct tmp_objdir *t)
+{
+ struct strbuf src = STRBUF_INIT, dst = STRBUF_INIT;
+ int ret;
+
+ if (!t)
+ return 0;
+
+ if (t->prev_odb) {
+ if (the_repository->objects->odb->will_destroy)
+ BUG("migrating an ODB that was marked for destruction");
+ restore_primary_odb(t->prev_odb, t->path.buf);
+ t->prev_odb = NULL;
+ }
+
+ strbuf_addbuf(&src, &t->path);
+ strbuf_addstr(&dst, get_object_directory());
+
+ ret = migrate_paths(&src, &dst);
+
+ strbuf_release(&src);
+ strbuf_release(&dst);
+
+ tmp_objdir_destroy(t);
+ return ret;
+}
+
+const char **tmp_objdir_env(const struct tmp_objdir *t)
+{
+ if (!t)
+ return NULL;
+ return t->env.v;
+}
+
+void tmp_objdir_add_as_alternate(const struct tmp_objdir *t)
+{
+ add_to_alternates_memory(t->path.buf);
+}
+
+void tmp_objdir_replace_primary_odb(struct tmp_objdir *t, int will_destroy)
+{
+ if (t->prev_odb)
+ BUG("the primary object database is already replaced");
+ t->prev_odb = set_temporary_primary_odb(t->path.buf, will_destroy);
+ t->will_destroy = will_destroy;
+}
+
+struct tmp_objdir *tmp_objdir_unapply_primary_odb(void)
+{
+ if (!the_tmp_objdir || !the_tmp_objdir->prev_odb)
+ return NULL;
+
+ restore_primary_odb(the_tmp_objdir->prev_odb, the_tmp_objdir->path.buf);
+ the_tmp_objdir->prev_odb = NULL;
+ return the_tmp_objdir;
+}
+
+void tmp_objdir_reapply_primary_odb(struct tmp_objdir *t, const char *old_cwd,
+ const char *new_cwd)
+{
+ char *path;
+
+ path = reparent_relative_path(old_cwd, new_cwd, t->path.buf);
+ strbuf_reset(&t->path);
+ strbuf_addstr(&t->path, path);
+ free(path);
+ tmp_objdir_replace_primary_odb(t, t->will_destroy);
+}