apr_tables.c

Apache V2.0.15 Alpha For Linuxhttpd-2_0_15-alpha.tar.Z

	}
    }
#endif

    for (i = 0; i < t->a.nelts; ) {
	if (!strcasecmp(elts[i].key, key)) {
	    if (!done) {
		elts[i].val = (char *)val;
		done = 1;
		++i;
	    }
	    else {		/* delete an extraneous element */
		for (j = i, k = i + 1; k < t->a.nelts; ++j, ++k) {
		    elts[j].key = elts[k].key;
		    elts[j].val = elts[k].val;
		}
		--t->a.nelts;
	    }
	}
	else {
	    ++i;
	}
    }

    if (!done) {
	elts = (apr_table_entry_t *) table_push(t);
	elts->key = (char *)key;
	elts->val = (char *)val;
    }
}

APR_DECLARE(void) apr_table_unset(apr_table_t *t, const char *key)
{
    register int i, j, k;
    apr_table_entry_t *elts = (apr_table_entry_t *) t->a.elts;

    for (i = 0; i < t->a.nelts; ) {
	if (!strcasecmp(elts[i].key, key)) {

	    /* found an element to skip over
	     * there are any number of ways to remove an element from
	     * a contiguous block of memory.  I've chosen one that
	     * doesn't do a memcpy/bcopy/array_delete, *shrug*...
	     */
	    for (j = i, k = i + 1; k < t->a.nelts; ++j, ++k) {
		elts[j].key = elts[k].key;
		elts[j].val = elts[k].val;
	    }
	    --t->a.nelts;
	}
	else {
	    ++i;
	}
    }
}

APR_DECLARE(void) apr_table_merge(apr_table_t *t, const char *key,
				 const char *val)
{
    apr_table_entry_t *elts = (apr_table_entry_t *) t->a.elts;
    int i;

    for (i = 0; i < t->a.nelts; ++i) {
	if (!strcasecmp(elts[i].key, key)) {
	    elts[i].val = apr_pstrcat(t->a.cont, elts[i].val, ", ", val, NULL);
	    return;
	}
    }

    elts = (apr_table_entry_t *) table_push(t);
    elts->key = apr_pstrdup(t->a.cont, key);
    elts->val = apr_pstrdup(t->a.cont, val);
}

APR_DECLARE(void) apr_table_mergen(apr_table_t *t, const char *key,
				  const char *val)
{
    apr_table_entry_t *elts = (apr_table_entry_t *) t->a.elts;
    int i;

#ifdef POOL_DEBUG
    {
	if (!apr_pool_is_ancestor(apr_find_pool(key), t->a.cont)) {
	    fprintf(stderr, "table_set: key not in ancestor pool of t\n");
	    abort();
	}
	if (!apr_pool_is_ancestor(apr_find_pool(val), t->a.cont)) {
	    fprintf(stderr, "table_set: key not in ancestor pool of t\n");
	    abort();
	}
    }
#endif

    for (i = 0; i < t->a.nelts; ++i) {
	if (!strcasecmp(elts[i].key, key)) {
	    elts[i].val = apr_pstrcat(t->a.cont, elts[i].val, ", ", val, NULL);
	    return;
	}
    }

    elts = (apr_table_entry_t *) table_push(t);
    elts->key = (char *)key;
    elts->val = (char *)val;
}

APR_DECLARE(void) apr_table_add(apr_table_t *t, const char *key,
			       const char *val)
{
    apr_table_entry_t *elts = (apr_table_entry_t *) t->a.elts;

    elts = (apr_table_entry_t *) table_push(t);
    elts->key = apr_pstrdup(t->a.cont, key);
    elts->val = apr_pstrdup(t->a.cont, val);
}

APR_DECLARE(void) apr_table_addn(apr_table_t *t, const char *key,
				const char *val)
{
    apr_table_entry_t *elts = (apr_table_entry_t *) t->a.elts;

#ifdef POOL_DEBUG
    {
	if (!apr_pool_is_ancestor(apr_find_pool(key), t->a.cont)) {
	    fprintf(stderr, "table_set: key not in ancestor pool of t\n");
	    abort();
	}
	if (!apr_pool_is_ancestor(apr_find_pool(val), t->a.cont)) {
	    fprintf(stderr, "table_set: key not in ancestor pool of t\n");
	    abort();
	}
    }
#endif

    elts = (apr_table_entry_t *) table_push(t);
    elts->key = (char *)key;
    elts->val = (char *)val;
}

APR_DECLARE(apr_table_t *) apr_table_overlay(apr_pool_t *p,
					     const apr_table_t *overlay,
					     const apr_table_t *base)
{
    apr_table_t *res;

#ifdef POOL_DEBUG
    /* we don't copy keys and values, so it's necessary that
     * overlay->a.pool and base->a.pool have a life span at least
     * as long as p
     */
    if (!apr_pool_is_ancestor(overlay->a.cont, p)) {
	fprintf(stderr,
		"overlay_tables: overlay's pool is not an ancestor of p\n");
	abort();
    }
    if (!apr_pool_is_ancestor(base->a.cont, p)) {
	fprintf(stderr,
		"overlay_tables: base's pool is not an ancestor of p\n");
	abort();
    }
#endif

    res = apr_palloc(p, sizeof(apr_table_t));
    /* behave like append_arrays */
    res->a.cont = p;
    copy_array_hdr_core(&res->a, &overlay->a);
    apr_array_cat(&res->a, &base->a);

    return res;
}

/* And now for something completely abstract ...

 * For each key value given as a vararg:
 *   run the function pointed to as
 *     int comp(void *r, char *key, char *value);
 *   on each valid key-value pair in the apr_table_t t that matches the vararg key,
 *   or once for every valid key-value pair if the vararg list is empty,
 *   until the function returns false (0) or we finish the table.
 *
 * Note that we restart the traversal for each vararg, which means that
 * duplicate varargs will result in multiple executions of the function
 * for each matching key.  Note also that if the vararg list is empty,
 * only one traversal will be made and will cut short if comp returns 0.
 *
 * Note that the table_get and table_merge functions assume that each key in
 * the apr_table_t is unique (i.e., no multiple entries with the same key).  This
 * function does not make that assumption, since it (unfortunately) isn't
 * true for some of Apache's tables.
 *
 * Note that rec is simply passed-on to the comp function, so that the
 * caller can pass additional info for the task.
 *
 * ADDENDUM for apr_table_vdo():
 * 
 * The caching api will allow a user to walk the header values:
 *
 * apr_status_t apr_cache_el_header_walk(apr_cache_el *el, 
 *    int (*comp)(void *, const char *, const char *), void *rec, ...);
 *
 * So it can be ..., however from there I use a  callback that use a va_list:
 *
 * apr_status_t (*cache_el_header_walk)(apr_cache_el *el, 
 *    int (*comp)(void *, const char *, const char *), void *rec, va_list);
 *
 * To pass those ...'s on down to the actual module that will handle walking
 * their headers, in the file case this is actually just an apr_table - and
 * rather than reimplementing apr_table_do (which IMHO would be bad) I just
 * called it with the va_list. For mod_shmem_cache I don't need it since I
 * can't use apr_table's, but mod_file_cache should (though a good hash would
 * be better, but that's a different issue :). 
 *
 * So to make mod_file_cache easier to maintain, it's a good thing
 */
APR_DECLARE(void) apr_table_do(int (*comp) (void *, const char *, const char *),
			      void *rec, const apr_table_t *t, ...)
{
    va_list vp;
    va_start(vp, t);
    apr_table_vdo(comp, rec, t, vp);
    va_end(vp);  
} 
APR_DECLARE(void) apr_table_vdo(int (*comp) (void *, const char *, const char *),
				void *rec, const apr_table_t *t, va_list vp)
{
    char *argp;
    apr_table_entry_t *elts = (apr_table_entry_t *) t->a.elts;
    int rv, i;
    argp = va_arg(vp, char *);
    do {
	for (rv = 1, i = 0; rv && (i < t->a.nelts); ++i) {
	    if (elts[i].key && (!argp || !strcasecmp(elts[i].key, argp))) {
		rv = (*comp) (rec, elts[i].key, elts[i].val);
	    }
	}
    } while (argp && ((argp = va_arg(vp, char *)) != NULL));
}

/* Curse libc and the fact that it doesn't guarantee a stable sort.  We
 * have to enforce stability ourselves by using the order field.  If it
 * provided a stable sort then we wouldn't even need temporary storage to
 * do the work below. -djg
 *
 * ("stable sort" means that equal keys retain their original relative
 * ordering in the output.)
 */
typedef struct {
    char *key;
    char *val;
    int order;
} overlap_key;

static int sort_overlap(const void *va, const void *vb)
{
    const overlap_key *a = va;
    const overlap_key *b = vb;
    int r;

    r = strcasecmp(a->key, b->key);
    if (r) {
	return r;
    }
    return a->order - b->order;
}

/* prefer to use the stack for temp storage for overlaps smaller than this */
#ifndef APR_OVERLAP_TABLES_ON_STACK
#define APR_OVERLAP_TABLES_ON_STACK	(512)
#endif

APR_DECLARE(void) apr_table_overlap(apr_table_t *a, const apr_table_t *b,
				    unsigned flags)
{
    overlap_key cat_keys_buf[APR_OVERLAP_TABLES_ON_STACK];
    overlap_key *cat_keys;
    int nkeys;
    apr_table_entry_t *e;
    apr_table_entry_t *last_e;
    overlap_key *left;
    overlap_key *right;
    overlap_key *last;

    nkeys = a->a.nelts + b->a.nelts;
    if (nkeys < APR_OVERLAP_TABLES_ON_STACK) {
	cat_keys = cat_keys_buf;
    }
    else {
	/* XXX: could use scratch free space in a or b's pool instead...
	 * which could save an allocation in b's pool.
	 */
	cat_keys = apr_palloc(b->a.cont, sizeof(overlap_key) * nkeys);
    }

    nkeys = 0;

    /* Create a list of the entries from a concatenated with the entries
     * from b.
     */
    e = (apr_table_entry_t *)a->a.elts;
    last_e = e + a->a.nelts;
    while (e < last_e) {
	cat_keys[nkeys].key = e->key;
	cat_keys[nkeys].val = e->val;
	cat_keys[nkeys].order = nkeys;
	++nkeys;
	++e;
    }

    e = (apr_table_entry_t *)b->a.elts;
    last_e = e + b->a.nelts;
    while (e < last_e) {
	cat_keys[nkeys].key = e->key;
	cat_keys[nkeys].val = e->val;
	cat_keys[nkeys].order = nkeys;
	++nkeys;
	++e;
    }

    qsort(cat_keys, nkeys, sizeof(overlap_key), sort_overlap);

    /* Now iterate over the sorted list and rebuild a.
     * Start by making sure it has enough space.
     */
    a->a.nelts = 0;
    if (a->a.nalloc < nkeys) {
	a->a.elts = apr_palloc(a->a.cont, a->a.elt_size * nkeys * 2);
	a->a.nalloc = nkeys * 2;
    }

    /*
     * In both the merge and set cases we retain the invariant:
     *
     * left->key, (left+1)->key, (left+2)->key, ..., (right-1)->key
     * are all equal keys.  (i.e. strcasecmp returns 0)
     *
     * We essentially need to find the maximal
     * right for each key, then we can do a quick merge or set as
     * appropriate.
     */

    if (flags & APR_OVERLAP_TABLES_MERGE) {
	left = cat_keys;
	last = left + nkeys;
	while (left < last) {
	    right = left + 1;
	    if (right == last
		|| strcasecmp(left->key, right->key)) {
		apr_table_addn(a, left->key, left->val);
		left = right;
	    }
	    else {
		char *strp;
		char *value;
		size_t len;

		/* Have to merge some headers.  Let's re-use the order field,
		 * since it's handy... we'll store the length of val there.
		 */
		left->order = strlen(left->val);
		len = left->order;
		do {
		    right->order = strlen(right->val);
		    len += 2 + right->order;
		    ++right;
		} while (right < last
			 && !strcasecmp(left->key, right->key));
		/* right points one past the last header to merge */
		value = apr_palloc(a->a.cont, len + 1);
		strp = value;
		for (;;) {
		    memcpy(strp, left->val, left->order);
		    strp += left->order;
		    ++left;
		    if (left == right) {
			break;
		    }
		    *strp++ = ',';
		    *strp++ = ' ';
		}
		*strp = 0;
		apr_table_addn(a, (left-1)->key, value);
	    }
	}
    }
    else {
	left = cat_keys;
	last = left + nkeys;
	while (left < last) {
	    right = left + 1;
	    while (right < last && !strcasecmp(left->key, right->key)) {
		++right;
	    }
	    apr_table_addn(a, (right-1)->key, (right-1)->val);
	    left = right;
	}
    }
}