libakerror/tests/err_release_refcount.c

#include "akerror.h"
#include "err_capture.h"
#include <string.h>

/*
 * akerr_release_error() drops one reference and only recycles the slot when the
 * last one goes away. Two of its refcount edges had no test:
 *
 *   - refcount > 1: the release must decrement and return the context intact,
 *     not wipe it out from under the reference that is still held.
 *   - refcount == 0: releasing a context nobody holds must not underflow the
 *     count; it wipes and returns NULL like any other fully-released slot.
 *
 * The macro API never produces a refcount above 1 (akerr_next_error() takes the
 * one reference a fresh slot gets), so this test sets the count directly to
 * model a caller that took an extra reference, and clears it to model a slot
 * nobody holds.
 */

int main(void)
{
    akerr_capture_install();
    akerr_init();
    AKERR_CHECK(akerr_slots_in_use() == 0);

    /* Check out a slot and give it two holders. */
    akerr_ErrorContext *held = akerr_next_error();
    AKERR_CHECK(held != NULL);
    int slotid = held->arrayid;
    held->refcount = 2;
    held->status = AKERR_VALUE;
    snprintf((char *)held->message, AKERR_MAX_ERROR_CONTEXT_STRING_LENGTH,
	     "still referenced");

    /* First release: one holder left, so the context survives untouched. */
    akerr_ErrorContext *ret = akerr_release_error(held);
    AKERR_CHECK(ret == held);
    AKERR_CHECK(held->refcount == 1);
    AKERR_CHECK(held->status == AKERR_VALUE);
    AKERR_CHECK(strcmp(held->message, "still referenced") == 0);
    AKERR_CHECK(akerr_slots_in_use() == 1);

    /* Second release: last holder gone, so the slot is wiped and recycled. */
    ret = akerr_release_error(held);
    AKERR_CHECK(ret == NULL);
    AKERR_CHECK(held->refcount == 0);
    AKERR_CHECK(held->status == 0);
    AKERR_CHECK(held->message[0] == '\0');
    /* The wipe must preserve the slot's identity and stacktrace cursor. */
    AKERR_CHECK(held->arrayid == slotid);
    AKERR_CHECK(held->stacktracebufptr == (char *)&held->stacktracebuf);
    AKERR_CHECK(akerr_slots_in_use() == 0);

    /*
     * Releasing an unheld slot: refcount is already 0, so there is nothing to
     * decrement and the count must not go negative.
     */
    akerr_ErrorContext *unheld = akerr_next_error();
    AKERR_CHECK(unheld != NULL);
    AKERR_CHECK(unheld->refcount == 1);
    unheld->refcount = 0;
    ret = akerr_release_error(unheld);
    AKERR_CHECK(ret == NULL);
    AKERR_CHECK(unheld->refcount == 0);
    AKERR_CHECK(akerr_slots_in_use() == 0);

    /* The pool is still healthy afterwards. */
    akerr_ErrorContext *probe = akerr_next_error();
    AKERR_CHECK(probe != NULL);

    fprintf(stderr, "err_release_refcount ok\n");
    return 0;
}