1 files changed, 281 insertions, 0 deletions

diff --git a/src/pq/pq_eval.c b/src/pq/pq_eval.c
new file mode 100644
index 000000000..0f28aec7e
--- /dev/null
+++ b/src/pq/pq_eval.c
@@ -0,0 +1,281 @@
+/*
+  This file is part of GNUnet
+  Copyright (C) 2017 GNUnet e.V.
+
+  GNUnet is free software; you can redistribute it and/or modify it under the
+  terms of the GNU General Public License as published by the Free Software
+  Foundation; either version 3, or (at your option) any later version.
+
+  GNUnet is distributed in the hope that it will be useful, but WITHOUT ANY
+  WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
+  A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
+
+  You should have received a copy of the GNU General Public License along with
+  GNUnet; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file pq/pq_eval.c
+ * @brief functions to execute SQL statements with arguments and/or results (PostGres)
+ * @author Christian Grothoff
+ */
+#include "platform.h"
+#include "gnunet_util_lib.h"
+#include "gnunet_pq_lib.h"
+
+
+/**
+ * Error code returned by Postgres for deadlock.
+ */
+#define PQ_DIAG_SQLSTATE_DEADLOCK "40P01"
+
+/**
+ * Error code returned by Postgres for uniqueness violation.
+ */
+#define PQ_DIAG_SQLSTATE_UNIQUE_VIOLATION "23505"
+
+/**
+ * Error code returned by Postgres on serialization failure.
+ */
+#define PQ_DIAG_SQLSTATE_SERIALIZATION_FAILURE "40001"
+
+
+/**
+ * Check the @a result's error code to see what happened.
+ * Also logs errors.
+ *
+ * @param connection connection to execute the statement in
+ * @param statement_name name of the statement that created @a result
+ * @param result result to check
+ * @return status code from the result, mapping PQ status
+ *         codes to `enum GNUNET_DB_QueryStatus`.  Never
+ *         returns positive values as this function does
+ *         not look at the result set.
+ * @deprecated (low level, let's see if we can do with just the high-level functions)
+ */
+enum GNUNET_DB_QueryStatus
+GNUNET_PQ_eval_result (PGconn *connection,
+                       const char *statement_name,
+                       PGresult *result)
+{
+  ExecStatusType est;
+
+  est = PQresultStatus (result);
+  if ( (PGRES_COMMAND_OK != est) &&
+       (PGRES_TUPLES_OK != est) )
+  {
+    const char *sqlstate;
+
+    sqlstate = PQresultErrorField (result,
+                                   PG_DIAG_SQLSTATE);
+    if (NULL == sqlstate)
+    {
+      /* very unexpected... */
+      GNUNET_break (0);
+      return GNUNET_DB_STATUS_HARD_ERROR;
+    }
+    if ( (0 == strcmp (sqlstate,
+                       PQ_DIAG_SQLSTATE_DEADLOCK)) ||
+         (0 == strcmp (sqlstate,
+                       PQ_DIAG_SQLSTATE_SERIALIZATION_FAILURE)) )
+    {
+      /* These two can be retried and have a fair chance of working
+         the next time */
+      GNUNET_log_from (GNUNET_ERROR_TYPE_INFO,
+                       "pq",
+                       "Query `%s' failed with result: %s/%s/%s/%s/%s\n",
+                       statement_name,
+                       PQresultErrorField (result,
+                                           PG_DIAG_MESSAGE_PRIMARY),
+                       PQresultErrorField (result,
+                                           PG_DIAG_MESSAGE_DETAIL),
+                       PQresultErrorMessage (result),
+                       PQresStatus (PQresultStatus (result)),
+                       PQerrorMessage (connection));
+      return GNUNET_DB_STATUS_SOFT_ERROR;
+    }
+    if (0 == strcmp (sqlstate,
+                     PQ_DIAG_SQLSTATE_UNIQUE_VIOLATION))
+    {
+      /* Likely no need to retry, INSERT of "same" data. */
+      GNUNET_log_from (GNUNET_ERROR_TYPE_DEBUG,
+                       "pq",
+                       "Query `%s' failed with unique violation: %s/%s/%s/%s/%s\n",
+                       statement_name,
+                       PQresultErrorField (result,
+                                           PG_DIAG_MESSAGE_PRIMARY),
+                       PQresultErrorField (result,
+                                           PG_DIAG_MESSAGE_DETAIL),
+                       PQresultErrorMessage (result),
+                       PQresStatus (PQresultStatus (result)),
+                       PQerrorMessage (connection));
+      return GNUNET_DB_STATUS_SUCCESS_NO_RESULTS;
+    }
+    GNUNET_log_from (GNUNET_ERROR_TYPE_ERROR,
+                     "pq",
+                     "Query `%s' failed with result: %s/%s/%s/%s/%s\n",
+                     statement_name,
+                     PQresultErrorField (result,
+                                         PG_DIAG_MESSAGE_PRIMARY),
+                     PQresultErrorField (result,
+                                         PG_DIAG_MESSAGE_DETAIL),
+                     PQresultErrorMessage (result),
+                     PQresStatus (PQresultStatus (result)),
+                     PQerrorMessage (connection));
+    return GNUNET_DB_STATUS_HARD_ERROR;
+  }
+  return GNUNET_DB_STATUS_SUCCESS_NO_RESULTS;
+}
+
+
+/**
+ * Execute a named prepared @a statement that is NOT a SELECT
+ * statement in @a connnection using the given @a params.  Returns the
+ * resulting session state.
+ *
+ * @param connection connection to execute the statement in
+ * @param statement_name name of the statement
+ * @param params parameters to give to the statement (#GNUNET_PQ_query_param_end-terminated)
+ * @return status code from the result, mapping PQ status
+ *         codes to `enum GNUNET_DB_QueryStatus`.  If the
+ *         statement was a DELETE or UPDATE statement, the
+ *         number of affected rows is returned.; if the
+ *         statment was an INSERT statement, and no row
+ *         was added due to a UNIQUE violation, we return
+ *         zero; if INSERT was successful, we return one.
+ */
+enum GNUNET_DB_QueryStatus
+GNUNET_PQ_eval_prepared_non_select (PGconn *connection,
+                                    const char *statement_name,
+                                    const struct GNUNET_PQ_QueryParam *params)
+{
+  PGresult *result;
+  enum GNUNET_DB_QueryStatus qs;
+
+  result = GNUNET_PQ_exec_prepared (connection,
+                                    statement_name,
+                                    params);
+  qs = GNUNET_PQ_eval_result (connection,
+                              statement_name,
+                              result);
+  if (GNUNET_DB_STATUS_SUCCESS_NO_RESULTS == qs)
+  {
+    const char *tuples;
+
+    /* What an awful API, this function really does return a string */
+    tuples = PQcmdTuples (result);
+    if (NULL != tuples)
+      qs = strtol (tuples, NULL, 10);
+  }
+  PQclear (result);
+  return qs;
+}
+
+
+/**
+ * Execute a named prepared @a statement that is a SELECT statement
+ * which may return multiple results in @a connection using the given
+ * @a params.  Call @a rh with the results.  Returns the query
+ * status including the number of results given to @a rh (possibly zero).
+ * @a rh will not have been called if the return value is negative.
+ *
+ * @param connection connection to execute the statement in
+ * @param statement_name name of the statement
+ * @param params parameters to give to the statement (#GNUNET_PQ_query_param_end-terminated)
+ * @param rh function to call with the result set, NULL to ignore
+ * @param rh_cls closure to pass to @a rh
+ * @return status code from the result, mapping PQ status
+ *         codes to `enum GNUNET_DB_QueryStatus`.
+ */
+enum GNUNET_DB_QueryStatus
+GNUNET_PQ_eval_prepared_multi_select (PGconn *connection,
+                                      const char *statement_name,
+                                      const struct GNUNET_PQ_QueryParam *params,
+                                      GNUNET_PQ_PostgresResultHandler rh,
+                                      void *rh_cls)
+{
+  PGresult *result;
+  enum GNUNET_DB_QueryStatus qs;
+  unsigned int ret;
+
+  result = GNUNET_PQ_exec_prepared (connection,
+                                    statement_name,
+                                    params);
+  qs = GNUNET_PQ_eval_result (connection,
+                              statement_name,
+                              result);
+  if (qs < 0)
+  {
+    PQclear (result);
+    return qs;
+  }
+  ret = PQntuples (result);
+  if (NULL != rh)
+    rh (rh_cls,
+        result,
+        ret);
+  PQclear (result);
+  return ret;
+}
+
+
+/**
+ * Execute a named prepared @a statement that is a SELECT statement
+ * which must return a single result in @a connection using the given
+ * @a params.  Stores the result (if any) in @a rs, which the caller
+ * must then clean up using #GNUNET_PQ_cleanup_result() if the return
+ * value was #GNUNET_DB_STATUS_SUCCESS_ONE_RESULT.  Returns the
+ * resulting session status.
+ *
+ * @param connection connection to execute the statement in
+ * @param statement_name name of the statement
+ * @param params parameters to give to the statement (#GNUNET_PQ_query_param_end-terminated)
+ * @param[in,out] rs result specification to use for storing the result of the query
+ * @return status code from the result, mapping PQ status
+ *         codes to `enum GNUNET_DB_QueryStatus`.
+ */
+enum GNUNET_DB_QueryStatus
+GNUNET_PQ_eval_prepared_singleton_select (PGconn *connection,
+                                          const char *statement_name,
+                                          const struct GNUNET_PQ_QueryParam *params,
+                                          struct GNUNET_PQ_ResultSpec *rs)
+{
+  PGresult *result;
+  enum GNUNET_DB_QueryStatus qs;
+
+  result = GNUNET_PQ_exec_prepared (connection,
+                                    statement_name,
+                                    params);
+  qs = GNUNET_PQ_eval_result (connection,
+                              statement_name,
+                              result);
+  if (qs < 0)
+  {
+    PQclear (result);
+    return qs;
+  }
+  if (0 == PQntuples (result))
+  {
+    PQclear (result);
+    return GNUNET_DB_STATUS_SUCCESS_NO_RESULTS;
+  }
+  if (1 != PQntuples (result))
+  {
+    /* more than one result, but there must be at most one */
+    GNUNET_break (0);
+    PQclear (result);
+    return GNUNET_DB_STATUS_HARD_ERROR;
+  }
+  if (GNUNET_OK !=
+      GNUNET_PQ_extract_result (result,
+                                rs,
+                                0))
+  {
+    PQclear (result);
+    return GNUNET_DB_STATUS_HARD_ERROR;
+  }
+  PQclear (result);
+  return GNUNET_DB_STATUS_SUCCESS_ONE_RESULT;
+}
+
+
+/* end of pq/pq_eval.c */