mirror of
https://github.com/git/git
synced 2024-08-28 12:09:19 +00:00
![Michael Haggerty](/assets/img/avatar_default.png)
The `trim` parameter can be set independently of `prefix`. So if some caller were to set `trim` to be greater than `strlen(prefix)`, we could end up pointing the `refname` field of the iterator past the NUL of the actual reference name string. That can't happen currently, because `trim` is always set either to zero or to `strlen(prefix)`. But even the latter could lead to confusion, if a refname is exactly equal to the prefix, because then we would set the outgoing `refname` to the empty string. And we're about to decouple the `prefix` and `trim` arguments even more, so let's be cautious here. Report a bug if ever asked to trim a reference whose name is not longer than `trim`. Signed-off-by: Michael Haggerty <mhagger@alum.mit.edu> Signed-off-by: Junio C Hamano <gitster@pobox.com>
401 lines
9.7 KiB
C
401 lines
9.7 KiB
C
/*
|
|
* 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)
|
|
{
|
|
iter->vtable = vtable;
|
|
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,
|
|
struct object_id *peeled)
|
|
{
|
|
die("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 = {
|
|
empty_ref_iterator_advance,
|
|
empty_ref_iterator_peel,
|
|
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);
|
|
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) {
|
|
die("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 = {
|
|
merge_ref_iterator_advance,
|
|
merge_ref_iterator_peel,
|
|
merge_ref_iterator_abort
|
|
};
|
|
|
|
struct ref_iterator *merge_ref_iterator_begin(
|
|
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);
|
|
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)
|
|
{
|
|
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;
|
|
}
|
|
|
|
return merge_ref_iterator_begin(front, back,
|
|
overlay_iterator_select, NULL);
|
|
}
|
|
|
|
struct prefix_ref_iterator {
|
|
struct ref_iterator base;
|
|
|
|
struct ref_iterator *iter0;
|
|
char *prefix;
|
|
int trim;
|
|
};
|
|
|
|
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) {
|
|
if (!starts_with(iter->iter0->refname, iter->prefix))
|
|
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)
|
|
die("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 = {
|
|
prefix_ref_iterator_advance,
|
|
prefix_ref_iterator_peel,
|
|
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 */
|
|
|
|
iter = xcalloc(1, sizeof(*iter));
|
|
ref_iterator = &iter->base;
|
|
|
|
base_ref_iterator_init(ref_iterator, &prefix_ref_iterator_vtable);
|
|
|
|
iter->iter0 = iter0;
|
|
iter->prefix = xstrdup(prefix);
|
|
iter->trim = trim;
|
|
|
|
return ref_iterator;
|
|
}
|
|
|
|
struct ref_iterator *current_ref_iter = NULL;
|
|
|
|
int do_for_each_ref_iterator(struct ref_iterator *iter,
|
|
each_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(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;
|
|
}
|