Append array using apr_array_push in D
I am writing a program in the D that uses svn and I came across something I can not figure out how to convert into D syntax. I took a stab at it but it segfaults.
Example of what I am trying to accomplish in C:
svn_auth_provider_object_t provider;
providers = apr_array_make(pool, 1, sizeof(svn_auth_provider_object_t*));
svn_auth_get_simple_provider2(&provider, null, null, pool);
*(svn_auth_provider_object_t**)apr_array_push (providers) = provider;
svn_auth_open(&auth_baton, providers, pool);
As far as I know, this code works just fine. I have found several examples done almost exactly the same way. Here is my attempt to copy this in D:
svn_auth_provider_object_t provider;
providers = apr_array_make(pool, 1, svn_auth_provider_object_t.sizeof);
svn_auth_get_simple_provider2(&provider, null, null, pool);
void* newSlot = apr_array_push(m);
newSlot = provider;
svn_auth_open(&auth_baton, providers, pool);
This throws a Segme开发者_如何学运维ntation Fault on svn_auth_open. My best guess is that the contents of provider are not ending up at the pointer held by newSlot. And I am not sure why that is.
Supplemental code:
/// Code taken from Apache's APR libary which is licensed under Apache License, Version 2.0
struct apr_array_header_t {
apr_pool_t* pool;
int elt_size;
int nelts;
int nalloc;
char* elts;
};
struct svn_auth_provider_object_t
{
svn_auth_provider_t *vtable;
void *provider_baton;
}
APR_DECLARE(void *) apr_array_push(apr_array_header_t *arr)
{
if (arr->nelts == arr->nalloc) {
int new_size = (arr->nalloc <= 0) ? 1 : arr->nalloc * 2;
char *new_data;
new_data = apr_palloc(arr->pool, arr->elt_size * new_size);
memcpy(new_data, arr->elts, arr->nalloc * arr->elt_size);
memset(new_data + arr->nalloc * arr->elt_size, 0,
arr->elt_size * (new_size - arr->nalloc));
arr->elts = new_data;
arr->nalloc = new_size;
}
++arr->nelts;
return arr->elts + (arr->elt_size * (arr->nelts - 1));
}
#define APR_ARRAY_IDX(ary,i,type) (((type *)(ary)->elts)[i])
#define APR_ARRAY_PUSH(ary,type) (*((type *)apr_array_push(ary)))
void
svn_auth_open(svn_auth_baton_t **auth_baton,
apr_array_header_t *providers,
apr_pool_t *pool)
{
svn_auth_baton_t *ab;
svn_auth_provider_object_t *provider;
int i;
/* Build the auth_baton. */
ab = apr_pcalloc(pool, sizeof(*ab));
ab->tables = apr_hash_make(pool);
ab->parameters = apr_hash_make(pool);
ab->creds_cache = apr_hash_make(pool);
ab->pool = pool;
/* Register each provider in order. Providers of different
credentials will be automatically sorted into different tables by
register_provider(). */
for (i = 0; i < providers->nelts; i++)
{
provider_set_t *table;
provider = APR_ARRAY_IDX(providers, i, svn_auth_provider_object_t *);
/* Add it to the appropriate table in the auth_baton */
table = apr_hash_get(ab->tables,
provider->vtable->cred_kind, APR_HASH_KEY_STRING);
if (! table)
{
table = apr_pcalloc(pool, sizeof(*table));
table->providers
= apr_array_make(pool, 1, sizeof(svn_auth_provider_object_t *));
apr_hash_set(ab->tables,
provider->vtable->cred_kind, APR_HASH_KEY_STRING,
table);
}
APR_ARRAY_PUSH(table->providers, svn_auth_provider_object_t *)
= provider;
}
*auth_baton = ab;
}
My best guess is that the segfault is happening in APR_ARRAY_IDX. Everything else has a valid memory address.
Additional information: This doesn't work either:
providers = apr_array_make(pool, 1, svn_auth_provider_object_t.sizeof);
svn_auth_provider_object_t* newSlot = cast(svn_auth_provider_object_t*) apr_array_push(providers);
svn_auth_get_simple_provider2(&newSlot, null, null, pool);
svn_auth_open(&auth_baton, providers, pool);
So that rules out my theory that the data wasn't going to the right place. However if I comment out the array push line and just send the array empty it works fine. So, this does not segfault:
providers = apr_array_make(pool, 1, svn_auth_provider_object_t.sizeof);
svn_auth_open(&auth_baton, providers, pool);
I also know it is not svn_auth_get_simple_provider2 because this segfaults as well...
providers = apr_array_make(pool, 1, svn_auth_provider_object_t.sizeof);
svn_auth_provider_object_t* newSlot = cast(svn_auth_provider_object_t*) apr_array_push(providers);
svn_auth_get_ssl_server_trust_file_provider(&newSlot, pool);
svn_auth_open(&auth_baton, providers, pool);
At first glance, the first assignment to newSlot is dead as the next line overwrites it, setting it to null
. Try:
auto newSlot = cast(svn_auth_provider_object_t**)apr_array_push(m);
*newSlot = provider;
This would have resulted in a compile time error if it hadn't been void*
.
I think the only part of the C version that isn't valid D is the cast.
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