Git Source Code Mirror - This is a publish-only repository and all pull requests are ignored. Please follow Documentation/SubmittingPatches procedure for any of your improvements. https://git-scm.com/
You can not select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
 
 
 
 
 
 
git/refs/iterator.c

435 lines
11 KiB

/*
* Generic reference iterator infrastructure. See refs-internal.h for
* documentation about the design and use of reference iterators.
*/
#include "cache.h"
#include "refs.h"
#include "refs/refs-internal.h"
#include "iterator.h"
int ref_iterator_advance(struct ref_iterator *ref_iterator)
{
return ref_iterator->vtable->advance(ref_iterator);
}
int ref_iterator_peel(struct ref_iterator *ref_iterator,
struct object_id *peeled)
{
return ref_iterator->vtable->peel(ref_iterator, peeled);
}
int ref_iterator_abort(struct ref_iterator *ref_iterator)
{
return ref_iterator->vtable->abort(ref_iterator);
}
void base_ref_iterator_init(struct ref_iterator *iter,
struct ref_iterator_vtable *vtable,
int ordered)
{
iter->vtable = vtable;
iter->ordered = !!ordered;
iter->refname = NULL;
iter->oid = NULL;
iter->flags = 0;
}
void base_ref_iterator_free(struct ref_iterator *iter)
{
/* Help make use-after-free bugs fail quickly: */
iter->vtable = NULL;
free(iter);
}
struct empty_ref_iterator {
struct ref_iterator base;
};
static int empty_ref_iterator_advance(struct ref_iterator *ref_iterator)
{
return ref_iterator_abort(ref_iterator);
}
static int empty_ref_iterator_peel(struct ref_iterator *ref_iterator UNUSED,
struct object_id *peeled UNUSED)
{
BUG("peel called for empty iterator");
}
static int empty_ref_iterator_abort(struct ref_iterator *ref_iterator)
{
base_ref_iterator_free(ref_iterator);
return ITER_DONE;
}
static struct ref_iterator_vtable empty_ref_iterator_vtable = {
.advance = empty_ref_iterator_advance,
.peel = empty_ref_iterator_peel,
.abort = empty_ref_iterator_abort,
};
struct ref_iterator *empty_ref_iterator_begin(void)
{
struct empty_ref_iterator *iter = xcalloc(1, sizeof(*iter));
struct ref_iterator *ref_iterator = &iter->base;
base_ref_iterator_init(ref_iterator, &empty_ref_iterator_vtable, 1);
return ref_iterator;
}
int is_empty_ref_iterator(struct ref_iterator *ref_iterator)
{
return ref_iterator->vtable == &empty_ref_iterator_vtable;
}
struct merge_ref_iterator {
struct ref_iterator base;
struct ref_iterator *iter0, *iter1;
ref_iterator_select_fn *select;
void *cb_data;
/*
* A pointer to iter0 or iter1 (whichever is supplying the
* current value), or NULL if advance has not yet been called.
*/
struct ref_iterator **current;
};
static int merge_ref_iterator_advance(struct ref_iterator *ref_iterator)
{
struct merge_ref_iterator *iter =
(struct merge_ref_iterator *)ref_iterator;
int ok;
if (!iter->current) {
/* Initialize: advance both iterators to their first entries */
if ((ok = ref_iterator_advance(iter->iter0)) != ITER_OK) {
iter->iter0 = NULL;
if (ok == ITER_ERROR)
goto error;
}
if ((ok = ref_iterator_advance(iter->iter1)) != ITER_OK) {
iter->iter1 = NULL;
if (ok == ITER_ERROR)
goto error;
}
} else {
/*
* Advance the current iterator past the just-used
* entry:
*/
if ((ok = ref_iterator_advance(*iter->current)) != ITER_OK) {
*iter->current = NULL;
if (ok == ITER_ERROR)
goto error;
}
}
/* Loop until we find an entry that we can yield. */
while (1) {
struct ref_iterator **secondary;
enum iterator_selection selection =
iter->select(iter->iter0, iter->iter1, iter->cb_data);
if (selection == ITER_SELECT_DONE) {
return ref_iterator_abort(ref_iterator);
} else if (selection == ITER_SELECT_ERROR) {
ref_iterator_abort(ref_iterator);
return ITER_ERROR;
}
if ((selection & ITER_CURRENT_SELECTION_MASK) == 0) {
iter->current = &iter->iter0;
secondary = &iter->iter1;
} else {
iter->current = &iter->iter1;
secondary = &iter->iter0;
}
if (selection & ITER_SKIP_SECONDARY) {
if ((ok = ref_iterator_advance(*secondary)) != ITER_OK) {
*secondary = NULL;
if (ok == ITER_ERROR)
goto error;
}
}
if (selection & ITER_YIELD_CURRENT) {
iter->base.refname = (*iter->current)->refname;
iter->base.oid = (*iter->current)->oid;
iter->base.flags = (*iter->current)->flags;
return ITER_OK;
}
}
error:
ref_iterator_abort(ref_iterator);
return ITER_ERROR;
}
static int merge_ref_iterator_peel(struct ref_iterator *ref_iterator,
struct object_id *peeled)
{
struct merge_ref_iterator *iter =
(struct merge_ref_iterator *)ref_iterator;
if (!iter->current) {
BUG("peel called before advance for merge iterator");
}
return ref_iterator_peel(*iter->current, peeled);
}
static int merge_ref_iterator_abort(struct ref_iterator *ref_iterator)
{
struct merge_ref_iterator *iter =
(struct merge_ref_iterator *)ref_iterator;
int ok = ITER_DONE;
if (iter->iter0) {
if (ref_iterator_abort(iter->iter0) != ITER_DONE)
ok = ITER_ERROR;
}
if (iter->iter1) {
if (ref_iterator_abort(iter->iter1) != ITER_DONE)
ok = ITER_ERROR;
}
base_ref_iterator_free(ref_iterator);
return ok;
}
static struct ref_iterator_vtable merge_ref_iterator_vtable = {
.advance = merge_ref_iterator_advance,
.peel = merge_ref_iterator_peel,
.abort = merge_ref_iterator_abort,
};
struct ref_iterator *merge_ref_iterator_begin(
int ordered,
struct ref_iterator *iter0, struct ref_iterator *iter1,
ref_iterator_select_fn *select, void *cb_data)
{
struct merge_ref_iterator *iter = xcalloc(1, sizeof(*iter));
struct ref_iterator *ref_iterator = &iter->base;
/*
* We can't do the same kind of is_empty_ref_iterator()-style
* optimization here as overlay_ref_iterator_begin() does,
* because we don't know the semantics of the select function.
* It might, for example, implement "intersect" by passing
* references through only if they exist in both iterators.
*/
base_ref_iterator_init(ref_iterator, &merge_ref_iterator_vtable, ordered);
iter->iter0 = iter0;
iter->iter1 = iter1;
iter->select = select;
iter->cb_data = cb_data;
iter->current = NULL;
return ref_iterator;
}
/*
* A ref_iterator_select_fn that overlays the items from front on top
* of those from back (like loose refs over packed refs). See
* overlay_ref_iterator_begin().
*/
static enum iterator_selection overlay_iterator_select(
struct ref_iterator *front, struct ref_iterator *back,
void *cb_data UNUSED)
{
int cmp;
if (!back)
return front ? ITER_SELECT_0 : ITER_SELECT_DONE;
else if (!front)
return ITER_SELECT_1;
cmp = strcmp(front->refname, back->refname);
if (cmp < 0)
return ITER_SELECT_0;
else if (cmp > 0)
return ITER_SELECT_1;
else
return ITER_SELECT_0_SKIP_1;
}
struct ref_iterator *overlay_ref_iterator_begin(
struct ref_iterator *front, struct ref_iterator *back)
{
/*
* Optimization: if one of the iterators is empty, return the
* other one rather than incurring the overhead of wrapping
* them.
*/
if (is_empty_ref_iterator(front)) {
ref_iterator_abort(front);
return back;
} else if (is_empty_ref_iterator(back)) {
ref_iterator_abort(back);
return front;
} else if (!front->ordered || !back->ordered) {
BUG("overlay_ref_iterator requires ordered inputs");
}
return merge_ref_iterator_begin(1, front, back,
overlay_iterator_select, NULL);
}
struct prefix_ref_iterator {
struct ref_iterator base;
struct ref_iterator *iter0;
char *prefix;
int trim;
};
/* Return -1, 0, 1 if refname is before, inside, or after the prefix. */
static int compare_prefix(const char *refname, const char *prefix)
{
while (*prefix) {
if (*refname != *prefix)
return ((unsigned char)*refname < (unsigned char)*prefix) ? -1 : +1;
refname++;
prefix++;
}
return 0;
}
static int prefix_ref_iterator_advance(struct ref_iterator *ref_iterator)
{
struct prefix_ref_iterator *iter =
(struct prefix_ref_iterator *)ref_iterator;
int ok;
while ((ok = ref_iterator_advance(iter->iter0)) == ITER_OK) {
int cmp = compare_prefix(iter->iter0->refname, iter->prefix);
if (cmp < 0)
continue;
if (cmp > 0) {
/*
* If the source iterator is ordered, then we
* can stop the iteration as soon as we see a
* refname that comes after the prefix:
*/
if (iter->iter0->ordered) {
ok = ref_iterator_abort(iter->iter0);
break;
} else {
continue;
}
}
if (iter->trim) {
/*
* It is nonsense to trim off characters that
* you haven't already checked for via a
* prefix check, whether via this
* `prefix_ref_iterator` or upstream in
* `iter0`). So if there wouldn't be at least
* one character left in the refname after
* trimming, report it as a bug:
*/
if (strlen(iter->iter0->refname) <= iter->trim)
BUG("attempt to trim too many characters");
iter->base.refname = iter->iter0->refname + iter->trim;
} else {
iter->base.refname = iter->iter0->refname;
}
iter->base.oid = iter->iter0->oid;
iter->base.flags = iter->iter0->flags;
return ITER_OK;
}
iter->iter0 = NULL;
if (ref_iterator_abort(ref_iterator) != ITER_DONE)
return ITER_ERROR;
return ok;
}
static int prefix_ref_iterator_peel(struct ref_iterator *ref_iterator,
struct object_id *peeled)
{
struct prefix_ref_iterator *iter =
(struct prefix_ref_iterator *)ref_iterator;
return ref_iterator_peel(iter->iter0, peeled);
}
static int prefix_ref_iterator_abort(struct ref_iterator *ref_iterator)
{
struct prefix_ref_iterator *iter =
(struct prefix_ref_iterator *)ref_iterator;
int ok = ITER_DONE;
if (iter->iter0)
ok = ref_iterator_abort(iter->iter0);
free(iter->prefix);
base_ref_iterator_free(ref_iterator);
return ok;
}
static struct ref_iterator_vtable prefix_ref_iterator_vtable = {
.advance = prefix_ref_iterator_advance,
.peel = prefix_ref_iterator_peel,
.abort = prefix_ref_iterator_abort,
};
struct ref_iterator *prefix_ref_iterator_begin(struct ref_iterator *iter0,
const char *prefix,
int trim)
{
struct prefix_ref_iterator *iter;
struct ref_iterator *ref_iterator;
if (!*prefix && !trim)
return iter0; /* optimization: no need to wrap iterator */
CALLOC_ARRAY(iter, 1);
ref_iterator = &iter->base;
base_ref_iterator_init(ref_iterator, &prefix_ref_iterator_vtable, iter0->ordered);
iter->iter0 = iter0;
iter->prefix = xstrdup(prefix);
iter->trim = trim;
return ref_iterator;
}
struct ref_iterator *current_ref_iter = NULL;
int do_for_each_repo_ref_iterator(struct repository *r, struct ref_iterator *iter,
each_repo_ref_fn fn, void *cb_data)
{
int retval = 0, ok;
struct ref_iterator *old_ref_iter = current_ref_iter;
current_ref_iter = iter;
while ((ok = ref_iterator_advance(iter)) == ITER_OK) {
retval = fn(r, iter->refname, iter->oid, iter->flags, cb_data);
if (retval) {
/*
* If ref_iterator_abort() returns ITER_ERROR,
* we ignore that error in deference to the
* callback function's return value.
*/
ref_iterator_abort(iter);
goto out;
}
}
out:
current_ref_iter = old_ref_iter;
if (ok == ITER_ERROR)
return -1;
return retval;
}