mongoc_cursor_t *
_mongoc_cursor_new (mongoc_client_t *client,
const char *db_and_collection,
mongoc_query_flags_t flags,
bson_uint32_t skip,
bson_uint32_t limit,
bson_uint32_t batch_size,
bson_bool_t is_command,
const bson_t *query,
const bson_t *fields,
const mongoc_read_prefs_t *read_prefs)
{
mongoc_read_mode_t mode;
mongoc_cursor_t *cursor;
const bson_t *tags;
const char *mode_str;
bson_t child;
ENTRY;
BSON_ASSERT(client);
BSON_ASSERT(db_and_collection);
BSON_ASSERT(query);
/* we can't have exhaust queries with limits */
BSON_ASSERT (!((flags & MONGOC_QUERY_EXHAUST) && limit));
/* we can't have exhaust queries with sharded clusters */
BSON_ASSERT (!((flags & MONGOC_QUERY_EXHAUST) && client->cluster.isdbgrid));
/*
* Cursors execute their query lazily. This sadly means that we must copy
* some extra data around between the bson_t structures. This should be
* small in most cases, so it reduces to a pure memcpy. The benefit to this
* design is simplified error handling by API consumers.
*/
cursor = bson_malloc0(sizeof *cursor);
cursor->client = client;
strncpy(cursor->ns, db_and_collection, sizeof cursor->ns - 1);
cursor->nslen = strlen(cursor->ns);
cursor->flags = flags;
cursor->skip = skip;
cursor->limit = limit;
cursor->batch_size = cursor->batch_size;
cursor->is_command = is_command;
if (!bson_has_field (query, "$query")) {
bson_init (&cursor->query);
bson_append_document (&cursor->query, "$query", 6, query);
} else {
bson_copy_to (query, &cursor->query);
}
if (read_prefs) {
cursor->read_prefs = mongoc_read_prefs_copy (read_prefs);
mode = mongoc_read_prefs_get_mode (read_prefs);
tags = mongoc_read_prefs_get_tags (read_prefs);
if (mode != MONGOC_READ_PRIMARY) {
flags |= MONGOC_QUERY_SLAVE_OK;
if ((mode != MONGOC_READ_SECONDARY_PREFERRED) || tags) {
bson_append_document_begin (&cursor->query, "$readPreference",
15, &child);
mode_str = _mongoc_cursor_get_read_mode_string (mode);
bson_append_utf8 (&child, "mode", 4, mode_str, -1);
if (tags) {
bson_append_array (&child, "tags", 4, tags);
}
bson_append_document_end (&cursor->query, &child);
}
}
}
if (fields) {
bson_copy_to(fields, &cursor->fields);
} else {
bson_init(&cursor->fields);
}
_mongoc_buffer_init(&cursor->buffer, NULL, 0, NULL);
mongoc_counter_cursors_active_inc();
RETURN(cursor);
}
mongoc_cursor_t *
_mongoc_cursor_new (mongoc_client_t *client,
const char *db_and_collection,
mongoc_query_flags_t flags,
uint32_t skip,
uint32_t limit,
uint32_t batch_size,
bool is_command,
const bson_t *query,
const bson_t *fields,
const mongoc_read_prefs_t *read_prefs)
{
mongoc_read_prefs_t *local_read_prefs = NULL;
mongoc_read_mode_t mode;
mongoc_cursor_t *cursor;
const bson_t *tags;
bson_iter_t iter;
const char *key;
const char *mode_str;
bson_t child;
bool found = false;
int i;
ENTRY;
BSON_ASSERT (client);
BSON_ASSERT (db_and_collection);
BSON_ASSERT (query);
if (!read_prefs) {
read_prefs = client->read_prefs;
}
cursor = bson_malloc0 (sizeof *cursor);
/*
* CDRIVER-244:
*
* If this is a command, we need to verify we can send it to the location
* specified by the read preferences. Otherwise, log a warning that we
* are rerouting to the primary instance.
*/
if (is_command &&
read_prefs &&
(mongoc_read_prefs_get_mode (read_prefs) != MONGOC_READ_PRIMARY) &&
bson_iter_init (&iter, query) &&
bson_iter_next (&iter) &&
(key = bson_iter_key (&iter))) {
for (i = 0; gSecondaryOkCommands [i]; i++) {
if (0 == strcasecmp (key, gSecondaryOkCommands [i])) {
found = true;
break;
}
}
if (!found) {
cursor->redir_primary = true;
local_read_prefs = mongoc_read_prefs_new (MONGOC_READ_PRIMARY);
read_prefs = local_read_prefs;
MONGOC_INFO ("Database command \"%s\" rerouted to primary node", key);
}
}
/*
* Cursors execute their query lazily. This sadly means that we must copy
* some extra data around between the bson_t structures. This should be
* small in most cases, so it reduces to a pure memcpy. The benefit to this
* design is simplified error handling by API consumers.
*/
cursor->client = client;
bson_strncpy (cursor->ns, db_and_collection, sizeof cursor->ns);
cursor->nslen = (uint32_t)strlen(cursor->ns);
cursor->flags = flags;
cursor->skip = skip;
cursor->limit = limit;
cursor->batch_size = batch_size;
cursor->is_command = is_command;
#define MARK_FAILED(c) \
do { \
(c)->failed = true; \
(c)->done = true; \
(c)->end_of_event = true; \
(c)->sent = true; \
} while (0)
/* we can't have exhaust queries with limits */
if ((flags & MONGOC_QUERY_EXHAUST) && limit) {
bson_set_error (&cursor->error,
MONGOC_ERROR_CURSOR,
MONGOC_ERROR_CURSOR_INVALID_CURSOR,
"Cannot specify MONGOC_QUERY_EXHAUST and set a limit.");
MARK_FAILED (cursor);
GOTO (finish);
}
/* we can't have exhaust queries with sharded clusters */
if ((flags & MONGOC_QUERY_EXHAUST) &&
(client->cluster.mode == MONGOC_CLUSTER_SHARDED_CLUSTER)) {
bson_set_error (&cursor->error,
MONGOC_ERROR_CURSOR,
MONGOC_ERROR_CURSOR_INVALID_CURSOR,
"Cannot specify MONGOC_QUERY_EXHAUST with sharded cluster.");
MARK_FAILED (cursor);
GOTO (finish);
}
/*
* Check types of various optional parameters.
*/
if (!is_command) {
if (bson_iter_init_find (&iter, query, "$explain") &&
!(BSON_ITER_HOLDS_BOOL (&iter) || BSON_ITER_HOLDS_INT32 (&iter))) {
bson_set_error (&cursor->error,
MONGOC_ERROR_CURSOR,
MONGOC_ERROR_CURSOR_INVALID_CURSOR,
"$explain must be a boolean.");
MARK_FAILED (cursor);
GOTO (finish);
}
if (bson_iter_init_find (&iter, query, "$snapshot") &&
!BSON_ITER_HOLDS_BOOL (&iter) &&
!BSON_ITER_HOLDS_INT32 (&iter)) {
bson_set_error (&cursor->error,
MONGOC_ERROR_CURSOR,
MONGOC_ERROR_CURSOR_INVALID_CURSOR,
"$snapshot must be a boolean.");
MARK_FAILED (cursor);
GOTO (finish);
}
}
if (!cursor->is_command && !bson_has_field (query, "$query")) {
bson_init (&cursor->query);
bson_append_document (&cursor->query, "$query", 6, query);
} else {
bson_copy_to (query, &cursor->query);
}
if (read_prefs) {
cursor->read_prefs = mongoc_read_prefs_copy (read_prefs);
mode = mongoc_read_prefs_get_mode (read_prefs);
tags = mongoc_read_prefs_get_tags (read_prefs);
if (mode != MONGOC_READ_PRIMARY) {
flags |= MONGOC_QUERY_SLAVE_OK;
if ((mode != MONGOC_READ_SECONDARY_PREFERRED) || tags) {
bson_append_document_begin (&cursor->query, "$readPreference",
15, &child);
mode_str = _mongoc_cursor_get_read_mode_string (mode);
bson_append_utf8 (&child, "mode", 4, mode_str, -1);
if (tags) {
bson_append_array (&child, "tags", 4, tags);
}
bson_append_document_end (&cursor->query, &child);
}
}
}
if (fields) {
bson_copy_to(fields, &cursor->fields);
} else {
bson_init(&cursor->fields);
}
_mongoc_buffer_init(&cursor->buffer, NULL, 0, NULL);
finish:
mongoc_counter_cursors_active_inc();
if (local_read_prefs) {
mongoc_read_prefs_destroy (local_read_prefs);
}
RETURN (cursor);
}
