Here is some work I've done on the SQLite driver for
apr_dbd. It's based on the work Ryan Phillips had
done. I've changed the select to build a linked list
of the result set so that the number of tuples will be
correct. The subsequent get rows retrieve the data
from the linked list. This works only if there is one
select in the query.
I have a general question about the query How should
the results be returned if there are multiple selects
in the query? Should it just return an array of
apr_results_t *.
Regards,
Rick Keiner
/* Copyright 2000-2005 The Apache Software Foundation or its licensors, as
* applicable.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include "apu.h"
#if APU_HAVE_SQLITE3
#include <ctype.h>
#include <stdlib.h>
#include <sqlite3.h>
#include "apr_strings.h"
#include "apr_time.h"
#define MAX_RETRY_COUNT 15
#define MAX_RETRY_SLEEP 100000
typedef struct apr_dbd_t apr_dbd_t;
typedef struct apr_dbd_results_t apr_dbd_results_t;
typedef struct apr_dbd_column_t apr_dbd_column_t;
typedef struct apr_dbd_row_t apr_dbd_row_t;
typedef struct {
int errnum;
apr_dbd_t *handle;
} apr_dbd_transaction_t;
struct apr_dbd_t {
sqlite3 *conn;
apr_dbd_transaction_t *trans;
apr_thread_mutex_t *mutex;
};
struct apr_dbd_row_t {
apr_dbd_results_t *res;
apr_dbd_column_t **columns;
apr_dbd_row_t *next_row;
int rownum;
} ;
struct apr_dbd_column_t {
char *name;
char *value;
int size;
int type;
} ;
struct apr_dbd_results_t {
int random;
sqlite3 *handle;
sqlite3_stmt *stmt;
apr_dbd_row_t *first_row;
apr_dbd_row_t *next_row;
size_t sz;
int tuples;
} ;
typedef struct {
const char *name;
int prepared;
} apr_dbd_prepared_t;
#define dbd_sqlite3_is_success(x) (((x) == SQLITE_DONE ) \
|| ((x) == SQLITE_OK ))
#define APR_DBD_INTERNAL
#include "apr_dbd.h"
static int dbd_sqlite3_select(apr_pool_t *pool, apr_dbd_t *sql,
apr_dbd_results_t **results,
const char *query, int seek)
{
sqlite3_stmt *stmt= NULL;
const char *tail = NULL;
int i, ret, retry_count;
size_t num_tuples=0;
int increment =0;
apr_dbd_row_t *row = NULL;
apr_dbd_row_t *lastrow = NULL;
apr_dbd_column_t *column;
char *hold = NULL;
apr_thread_mutex_lock(sql->mutex);
ret = sqlite3_prepare(sql->conn, query, strlen(query), &stmt, &tail);
if(!dbd_sqlite3_is_success(ret)) {
apr_thread_mutex_unlock(sql->mutex);
return ret;
}
else {
int column_count;
column_count = sqlite3_column_count(stmt);
if (!*results) {
*results = apr_pcalloc(pool, sizeof(apr_dbd_results_t));
}
(*results)->stmt = stmt;
(*results)->sz = column_count;
(*results)->random = seek;
(*results)->next_row = 0;
(*results)->tuples = 0;
apr_pool_cleanup_register(pool, stmt, (void*)sqlite3_finalize,
apr_pool_cleanup_null);
while (1) {
ret = sqlite3_step((*results)->stmt);
if(ret == SQLITE_BUSY) {
if(retry_count++ > MAX_RETRY_COUNT) {
apr_thread_mutex_unlock(sql->mutex);
return -1;
}
apr_thread_mutex_unlock(sql->mutex);
apr_sleep(MAX_RETRY_SLEEP);
} else if(ret == SQLITE_ERROR || ret == SQLITE_MISUSE) {
apr_thread_mutex_unlock(sql->mutex);
return ret;
} else if (ret == SQLITE_ROW) {
int length ;
apr_dbd_column_t * col;
row = apr_palloc(pool, sizeof(apr_dbd_row_t));
row->res = *results;
row->res->stmt = (*results)->stmt;
increment = sizeof(apr_dbd_column_t *);
length = increment * (*results)->sz ;
row->columns = apr_palloc(pool, length);
for (i=0; i < (*results)->sz; i++) {
column = apr_palloc(pool, sizeof(apr_dbd_column_t));
row->columns[i] = column;
column->name = (char *)sqlite3_column_name((*results)->stmt, i);
column->size = sqlite3_column_bytes((*results)->stmt, i);
column->type = sqlite3_column_type((*results)->stmt, i);
switch (column->type) {
case SQLITE_FLOAT:
break;
case SQLITE_INTEGER:
case SQLITE_TEXT:
hold = NULL;
hold = (char *)sqlite3_column_text((*results)->stmt, i);
if (hold) {
column->value = apr_palloc(pool, column->size + 1);
strncpy(column->value, hold, column->size +1);
}
break;
case SQLITE_BLOB:
break;
case SQLITE_NULL:
break;
}
col = row->columns[i] ;
}
row->rownum = num_tuples++;
row->next_row = 0;
(*results)->tuples = num_tuples;
if ((*results)->next_row == 0) {
(*results)->next_row = row;
}
if (lastrow != 0) {
lastrow->next_row = row;
}
lastrow = row;
} else if (ret == SQLITE_DONE ) {
apr_thread_mutex_unlock(sql->mutex);
return 0;
} else {
apr_thread_mutex_unlock(sql->mutex);
return ret;
}
}
}
apr_thread_mutex_unlock(sql->mutex);
return 0;
}
static int dbd_sqlite3_get_row(apr_pool_t *pool, apr_dbd_results_t *res,
apr_dbd_row_t **rowp, int rownum)
{
int ret, retry_count, i = 0;
apr_dbd_row_t *row;
if (rownum == -1) {
*rowp = res->next_row;
if (*rowp == 0 ) return -1;
res->next_row = (*rowp)->next_row;
return 0;
}
if (rownum > res->tuples) {
return -1;
}
*rowp = res->next_row;
for (; *rowp != 0; i++ , *rowp=(*rowp)->next_row) {
if (i == rownum) {
return 0;
}
}
return -1;
}
static const char *dbd_sqlite3_get_entry(const apr_dbd_row_t *row, int n)
{
apr_dbd_column_t * column = row->columns[n];
char * value = column->value;
return value;
}
static const char *dbd_sqlite3_error(apr_dbd_t *sql, int n)
{
return (const char*)sqlite3_errmsg(sql->conn);
}
static int dbd_sqlite3_query(apr_dbd_t *sql, int *nrows, const char *query)
{
sqlite3_stmt *stmt= NULL;
const char *tail = NULL;
int ret, retry_count=0, length=0;
apr_status_t res;
apr_pool_t *pool;
res = apr_pool_create(&pool, NULL);
if (res != APR_SUCCESS) {
return SQLITE_ERROR;
}
length = strlen(query);
apr_thread_mutex_lock(sql->mutex);
do {
ret = sqlite3_prepare(sql->conn, query, length, &stmt, &tail);
if(ret != SQLITE_OK) {
sqlite3_finalize(stmt);
apr_thread_mutex_unlock(sql->mutex);
return ret;
}
ret = sqlite3_step(stmt);
*nrows = sqlite3_changes(sql->conn);
sqlite3_finalize(stmt);
length -= (tail - query);
query = tail;
} while(length > 0);
if(dbd_sqlite3_is_success(ret)) {
ret = 0;
}
apr_thread_mutex_unlock(sql->mutex);
apr_pool_destroy(pool);
return ret;
}
static const char *dbd_sqlite3_escape(apr_pool_t *pool, const char *arg,
apr_dbd_t *sql)
{
char *ret = sqlite3_mprintf(arg);
apr_pool_cleanup_register(pool, ret, (void*)sqlite3_free,
apr_pool_cleanup_null);
return ret;
}
static int dbd_sqlite3_prepare(apr_pool_t *pool, apr_dbd_t *sql,
const char *query, const char *label,
apr_dbd_prepared_t **statement)
{
return APR_ENOTIMPL;
}
static int dbd_sqlite3_pquery(apr_pool_t *pool, apr_dbd_t *sql,
int *nrows, apr_dbd_prepared_t *statement,
int nargs, const char **values)
{
return APR_ENOTIMPL;
}
static int dbd_sqlite3_pvquery(apr_pool_t *pool, apr_dbd_t *sql,
int *nrows, apr_dbd_prepared_t *statement, ...)
{
return APR_ENOTIMPL;
}
static int dbd_sqlite3_pselect(apr_pool_t *pool, apr_dbd_t *sql,
apr_dbd_results_t **results,
apr_dbd_prepared_t *statement,
int seek, int nargs, const char **values)
{
return APR_ENOTIMPL;
}
static int dbd_sqlite3_pvselect(apr_pool_t *pool, apr_dbd_t *sql,
apr_dbd_results_t **results,
apr_dbd_prepared_t *statement,
int seek, ...)
{
return APR_ENOTIMPL;
}
static int dbd_sqlite3_start_transaction(apr_pool_t *pool, apr_dbd_t *handle,
apr_dbd_transaction_t **trans)
{
int ret = 0;
int nrows = 0;
ret = dbd_sqlite3_query(handle, &nrows, "BEGIN TRANSACTION;");
if (!*trans) {
*trans = apr_pcalloc(pool, sizeof(apr_dbd_transaction_t));
(*trans)->handle = handle;
handle->trans = *trans;
}
return ret;
}
static int dbd_sqlite3_end_transaction(apr_dbd_transaction_t *trans)
{
int ret = 0;
int nrows = 0;
if(trans) {
ret = dbd_sqlite3_query(trans->handle, &nrows, "END TRANSACTION;");
if (trans->errnum) {
trans->errnum = 0;
ret = dbd_sqlite3_query(trans->handle, &nrows, "ROLLBACK;");
}
else {
ret = dbd_sqlite3_query(trans->handle, &nrows, "COMMIT;");
}
trans->handle->trans = NULL;
}
return ret;
}
static apr_dbd_t *dbd_sqlite3_open(apr_pool_t *pool, const char *params)
{
apr_dbd_t *sql = NULL;
sqlite3* conn = NULL;
apr_status_t res;
int sqlres;
if(!params) return NULL;
sqlres = sqlite3_open(params, &conn);
if(sqlres != SQLITE_OK) {
sqlite3_close(conn);
return NULL;
}
/* should we register rand or power functions to the sqlite VM? */
sql = apr_pcalloc (pool, sizeof (*sql));
sql->conn = conn;
/* Create a mutex */
res = apr_thread_mutex_create(&sql->mutex, APR_THREAD_MUTEX_NESTED, /* nested */
pool);
if (res != APR_SUCCESS) {
return NULL;
}
return sql;
}
static apr_status_t dbd_sqlite3_close(apr_dbd_t *handle)
{
sqlite3_close(handle->conn);
apr_thread_mutex_destroy(handle->mutex);
return APR_SUCCESS;
}
static apr_status_t dbd_sqlite3_check_conn(apr_pool_t *pool,
apr_dbd_t *handle)
{
return (handle->conn != NULL)?APR_SUCCESS:APR_EGENERAL;
}
static int dbd_sqlite3_select_db(apr_pool_t *pool, apr_dbd_t *handle,
const char *name)
{
return APR_ENOTIMPL;
}
static void *dbd_sqlite3_native(apr_dbd_t *handle)
{
return handle->conn;
}
static int dbd_sqlite3_num_cols(apr_dbd_results_t* res)
{
return res->sz;
}
static int dbd_sqlite3_num_tuples(apr_dbd_results_t* res)
{
return res->tuples;
}
APU_DECLARE_DATA const apr_dbd_driver_t apr_dbd_sqlite3_driver = {
"sqlite3",
NULL,
dbd_sqlite3_native,
dbd_sqlite3_open,
dbd_sqlite3_check_conn,
dbd_sqlite3_close,
dbd_sqlite3_select_db,
dbd_sqlite3_start_transaction,
dbd_sqlite3_end_transaction,
dbd_sqlite3_query,
dbd_sqlite3_select,
dbd_sqlite3_num_cols,
dbd_sqlite3_num_tuples,
dbd_sqlite3_get_row,
dbd_sqlite3_get_entry,
dbd_sqlite3_error,
dbd_sqlite3_escape,
dbd_sqlite3_prepare,
dbd_sqlite3_pvquery,
dbd_sqlite3_pvselect,
dbd_sqlite3_pquery,
dbd_sqlite3_pselect,
};
#endif
