revising backenddb-API, towards pluginificiation

5 files changed, 196 insertions, 231 deletions

diff --git a/configure.ac b/configure.ac
index b66b8b00..fd7c9981 100644
--- a/configure.ac
+++ b/configure.ac
@@ -50,14 +50,12 @@ AS_IF([test $libgnunetutil != 1],
 *** ]])])
 
 
-# check for libpq (postgresql)
+# test for postgres
 AX_LIB_POSTGRESQL([9.3])
-AS_IF([test ! "$found_postgresql" = "yes"],
-  [AC_MSG_ERROR([[
-***
-*** You need postgresql / libpq to build this program.
-*** ]])])
-
+if test "$found_postgresql" = "yes"; then
+  postgres=true
+fi
+AM_CONDITIONAL(HAVE_POSTGRESQL, test x$postgres = xtrue)
 
 # Check for Taler's libtalerpq
 libtalerpq=0
@@ -81,13 +79,7 @@ AC_CHECK_HEADERS([taler/taler_pq_lib.h],
    [], [#ifdef HAVE_GNUNET_PLATFORM_H
         #include <gnunet/platform.h>
        #endif])
-AS_IF([test $libtalerpq != 1],
-  [AC_MSG_ERROR([[
-***
-*** You need libtalerpq to build this program.
-*** This library is part of the Taler MINT, available at
-***   https://taler.net
-*** ]])])
+AM_CONDITIONAL(HAVE_TALERPQ, test x$libtalerpq = x1)
 
 
 # check for libmicrohttpd
diff --git a/src/backenddb/Makefile.am b/src/backenddb/Makefile.am
index 8139e9c8..02656185 100644
--- a/src/backenddb/Makefile.am
+++ b/src/backenddb/Makefile.am
@@ -1,17 +1,38 @@
 # This Makefile.am is in the public domain
 AM_CPPFLAGS = -I$(top_srcdir)/src/include
 
+plugindir = $(libdir)/taler
+
+if HAVE_POSTGRESQL
+if HAVE_TALERPQ
+plugin_LTLIBRARIES = \
+  libtaler_plugin_merchantdb_postgres.la
+endif
+endif
+
 lib_LTLIBRARIES = \
   libtalermerchantdb.la
 
 libtalermerchantdb_la_SOURCES = \
-  merchant_db.c
+  merchantdb_plugin.c
 
 libtalermerchantdb_la_LIBADD = \
   $(LIBGCRYPT_LIBS) \
   -ltalerutil \
-  -lgnunetutil \
+  -lgnunetutil
+
+libtalermerchantdb_la_LDFLAGS = \
+  $(POSTGRESQL_LDFLAGS) \
+  -version-info 0:0:0 \
+  -no-undefined
+
+libtaler_plugin_merchantdb_postgres_la_SOURCES = \
+  plugin_merchantdb_postgres.c
+libtaler_plugin_merchantdb_postgres_la_LIBADD = \
+  $(LTLIBINTL)
+libtaler_plugin_merchantdb_postgres_la_LDFLAGS = \
+  $(TALER_PLUGIN_LDFLAGS) \
   -ltalerpq \
-  -lgnunetpostgres \
+  -ltalerutil \
   -lpq \
-  -lpthread
+  -lgnunetutil $(XLIB)
diff --git a/src/backenddb/merchantdb_plugin.c b/src/backenddb/merchantdb_plugin.c
new file mode 100644
index 00000000..62a1a193
--- /dev/null
+++ b/src/backenddb/merchantdb_plugin.c
@@ -0,0 +1,150 @@
+/*
+  This file is part of TALER
+  Copyright (C) 2015 Christian Grothoff (and other contributing authors)
+
+  TALER 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.
+
+  TALER 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
+  TALER; see the file COPYING.  If not, If not, see <http://www.gnu.org/licenses/>
+*/
+/**
+ * @file merchantdb/merchantdb_plugin.c
+ * @brief Logic to load database plugin
+ * @author Christian Grothoff
+ * @author Sree Harsha Totakura <sreeharsha@totakura.in>
+ */
+#include "platform.h"
+#include <taler/taler_util.h>
+#include "taler_merchantdb_plugin.h"
+#include <ltdl.h>
+
+
+/**
+ * Initialize the plugin.
+ *
+ * @param cfg configuration to use
+ * @return #GNUNET_OK on success
+ */
+struct TALER_MERCHANTDB_Plugin *
+TALER_MERCHANTDB_plugin_load (const struct GNUNET_CONFIGURATION_Handle *cfg)
+{
+  char *plugin_name;
+  char *lib_name;
+  struct GNUNET_CONFIGURATION_Handle *cfg_dup;
+  struct TALER_MERCHANTDB_Plugin *plugin;
+
+  if (GNUNET_SYSERR ==
+      GNUNET_CONFIGURATION_get_value_string (cfg,
+                                             "merchant",
+                                             "db",
+                                             &plugin_name))
+  {
+    GNUNET_log_config_missing (GNUNET_ERROR_TYPE_ERROR,
+                               "merchant",
+                               "db");
+    return NULL;
+  }
+  (void) GNUNET_asprintf (&lib_name,
+                          "libtaler_plugin_merchantdb_%s",
+                          plugin_name);
+  GNUNET_free (plugin_name);
+  cfg_dup = GNUNET_CONFIGURATION_dup (cfg);
+  plugin = GNUNET_PLUGIN_load (lib_name, cfg_dup);
+  if (NULL != plugin)
+    plugin->library_name = lib_name;
+  else
+    GNUNET_free (lib_name);
+  GNUNET_CONFIGURATION_destroy (cfg_dup);
+  return plugin;
+}
+
+
+/**
+ * Shutdown the plugin.
+ *
+ * @param plugin the plugin to unload
+ */
+void
+TALER_MERCHANTDB_plugin_unload (struct TALER_MERCHANTDB_Plugin *plugin)
+{
+  char *lib_name;
+
+  if (NULL == plugin)
+    return;
+  lib_name = plugin->library_name;
+  GNUNET_assert (NULL == GNUNET_PLUGIN_unload (lib_name,
+                                               plugin));
+  GNUNET_free (lib_name);
+}
+
+
+/**
+ * Libtool search path before we started.
+ */
+static char *old_dlsearchpath;
+
+
+/**
+ * Setup libtool paths.
+ */
+void __attribute__ ((constructor))
+plugin_init ()
+{
+  int err;
+  const char *opath;
+  char *path;
+  char *cpath;
+
+  err = lt_dlinit ();
+  if (err > 0)
+  {
+    FPRINTF (stderr,
+             _("Initialization of plugin mechanism failed: %s!\n"),
+             lt_dlerror ());
+    return;
+  }
+  opath = lt_dlgetsearchpath ();
+  if (NULL != opath)
+    old_dlsearchpath = GNUNET_strdup (opath);
+  path = TALER_OS_installation_get_path (GNUNET_OS_IPK_LIBDIR);
+  if (NULL != path)
+  {
+    if (NULL != opath)
+    {
+      GNUNET_asprintf (&cpath, "%s:%s", opath, path);
+      lt_dlsetsearchpath (cpath);
+      GNUNET_free (path);
+      GNUNET_free (cpath);
+    }
+    else
+    {
+      lt_dlsetsearchpath (path);
+      GNUNET_free (path);
+    }
+  }
+}
+
+
+/**
+ * Shutdown libtool.
+ */
+void __attribute__ ((destructor))
+plugin_fini ()
+{
+  lt_dlsetsearchpath (old_dlsearchpath);
+  if (NULL != old_dlsearchpath)
+  {
+    GNUNET_free (old_dlsearchpath);
+    old_dlsearchpath = NULL;
+  }
+  lt_dlexit ();
+}
+
+
+/* end of merchantdb_plugin.c */
diff --git a/src/backenddb/merchant_db.c b/src/backenddb/plugin_merchantdb_postgres.c
index d8bef636..02e6884b 100644
--- a/src/backenddb/merchant_db.c
+++ b/src/backenddb/plugin_merchantdb_postgres.c
@@ -21,9 +21,10 @@
  */
 #include "platform.h"
 #include <gnunet/gnunet_util_lib.h>
+#include <gnunet/gnunet_postgres_lib.h>
 #include <taler/taler_util.h>
 #include <taler/taler_pq_lib.h>
-#include "taler_merchantdb_lib.h"
+#include "taler_merchantdb_plugin.h"
 
 /**
  * Shorthand for exit jumps.
@@ -616,56 +617,3 @@ TALER_MERCHANTDB_contract_get_values (PGconn *conn,
   PQclear (res);
   return GNUNET_SYSERR;
 }
-
-
-/**
- * Get a set of values representing a contract. This function is meant
- * to obsolete the '_get_contract_values' version.
- *
- * @param h_contract the hashcode of this contract
- * @param contract_handle where to store the results
- * @raturn GNUNET_OK in case of success, GNUNET_SYSERR
- * upon errors
- */
-uint32_t
-TALER_MERCHANTDB_contract_get_handle (PGconn *conn,
-                                 const struct GNUNET_HashCode *h_contract,
-				 struct TALER_MERCHANTDB_ContractHandle *contract_handle)
-{
-  struct TALER_MERCHANTDB_ContractHandle ch;
-  PGresult *res;
-  ExecStatusType status;
-
-  struct TALER_PQ_QueryParam params[] = {
-      TALER_PQ_query_param_fixed_size (h_contract, sizeof (struct GNUNET_HashCode)),
-      TALER_PQ_query_param_end
-  };
-
-  struct TALER_PQ_ResultSpec rs[] = {
-   TALER_PQ_result_spec_uint64 ("nounce", &ch.nounce),
-   TALER_PQ_result_spec_absolute_time ("edate", &ch.edate),
-   TALER_PQ_result_spec_absolute_time ("timestamp", &ch.timestamp),
-   TALER_PQ_result_spec_absolute_time ("refund_deadline", &ch.refund_deadline),
-   TALER_PQ_result_spec_uint64 ("contract_id", &ch.contract_id),
-   TALER_PQ_result_spec_end
-  };
-
-  res = TALER_PQ_exec_prepared (conn, "get_contract_set", params);
-  status = PQresultStatus (res);
-  EXITIF (PGRES_TUPLES_OK != status);
-  if (0 == PQntuples (res))
-  {
-    TALER_LOG_DEBUG ("Contract not found");
-    goto EXITIF_exit;
-  }
-
-  EXITIF (1 != PQntuples (res));
-  EXITIF (GNUNET_YES != TALER_PQ_extract_result (res, rs, 0));
-  *contract_handle = ch;
-  PQclear (res);
-  return GNUNET_OK;
-
-  EXITIF_exit:
-  PQclear (res);
-  return GNUNET_SYSERR;
-}
diff --git a/src/include/taler_merchantdb_lib.h b/src/include/taler_merchantdb_lib.h
index fe5adffc..f64a9bfa 100644
--- a/src/include/taler_merchantdb_lib.h
+++ b/src/include/taler_merchantdb_lib.h
@@ -19,182 +19,36 @@
  * @brief database helper functions used by the merchant backend
  * @author Sree Harsha Totakura <sreeharsha@totakura.in>
  */
+#ifndef TALER_MERCHANTDB_LIB_H
+#define TALER_MERCHANTDB_LIB_H
 
-#ifndef MERCHANT_DB_H
-#define MERCHANT_DB_H
-
-#include <gnunet/gnunet_postgres_lib.h>
 #include <taler/taler_util.h>
+#include "taler_merchantdb_plugin.h"
 
-
-
-/* Set of values that represent a contract. To be expanded on an
-  as-needed basis */
-struct TALER_MERCHANTDB_ContractHandle
-{
-  /* The nounce used when hashing the wire details
-    for this contract */
-  uint64_t nounce;
-
-  /* The maximum time when the merchant expects the money tranfer
-    to his bank account to happen */
-  struct GNUNET_TIME_Absolute edate;
-
-  /* The time when this contract was generated */
-  struct GNUNET_TIME_Absolute timestamp;
-
-  /* The maximum time until which the merchant could issue a
-    refund to the customer */
-  struct GNUNET_TIME_Absolute refund_deadline;
-
-  /* The identification number for this contract */
-  uint64_t contract_id;
-
-};
+/**
+ * Handle to interact with the database.
+ */
+struct TALER_MERCHANTDB_Plugin;
 
 /**
  * Connect to postgresql database
  *
  * @param cfg the configuration handle
- * @return connection to the postgresql database; NULL upon error
+ * @return connection to the database; NULL upon error
  */
-PGconn *
-TALER_MERCHANTDB_connect (const struct GNUNET_CONFIGURATION_Handle *cfg);
+struct TALER_MERCHANTDB_Plugin *
+TALER_MERCHANTDB_plugin_load (const struct GNUNET_CONFIGURATION_Handle *cfg);
 
 
 /**
  * Disconnect from the database
  *
- * @param conn database handle to close
+ * @param dbh database handle to close
  */
 void
-TALER_MERCHANTDB_disconnect (PGconn *conn);
-
-
-/**
- * Initialize merchant tables
- *
- * @param conn the connection handle to postgres db.
- * @param tmp GNUNET_YES if the tables are to be made temporary i.e. their
- *          contents are dropped when the @a conn is closed
- * @return GNUNET_OK upon success; GNUNET_SYSERR upon failure
- */
-int
-TALER_MERCHANTDB_initialize (PGconn *conn, int tmp);
-
-
-/**
- * Inserts a contract record into the database and if successfull returns the
- * serial number of the inserted row.
- *
- * @param conn the database connection
- * @param timestamp the timestamp of this contract
- * @param expiry the time when the contract will expire
- * @param edate when the merchant wants to receive the wire transfer corresponding
- * to this deal (this value is also a field inside the 'wire' JSON format)
- * @param refund deadline until which the merchant can return the paid amount
- * @param amount the taler amount corresponding to the contract
- * @param hash of the stringified JSON corresponding to this contract
- * @param c_id contract's id
- * @param desc descripition of the contract
- * @param nounce a random 64-bit nounce
- * @param product description to identify a product
- * @return #GNUNET_OK on success, #GNUNET_SYSERR upon error
- */
-uint32_t
-TALER_MERCHANTDB_contract_create (PGconn *conn,
-                             const struct GNUNET_TIME_Absolute timestamp,
-                             const struct GNUNET_TIME_Absolute expiry,
-			     struct GNUNET_TIME_Absolute edate,
-			     struct GNUNET_TIME_Absolute refund,
-                             const struct TALER_Amount *amount,
-			     const struct GNUNET_HashCode *h_contract,
-			     uint64_t c_id,
-                             const char *desc,
-                             uint64_t nounce,
-                             uint64_t product);
+TALER_MERCHANTDB_plugin_unload (struct TALER_MERCHANTDB_Plugin *dbh);
 
 
-long long
-TALER_MERCHANTDB_contract_get_product (PGconn *conn,
-                                  uint64_t contract_id);
-
-
-/**
- * Update the pending column of a deposit permission
- *
- * @param conn handle to DB
- * @param transaction_id identification number of the deposit to
- * update
- * @param pending true if still pending, false otherwise (i.e. the
- * mint did respond something)
- * @return #GNUNET_OK if successful, #GNUNET_SYSERR upon errors
- */
-uint32_t
-TALER_MERCHANTDB_deposit_permission_update (PGconn *conn,
-                                       uint64_t transaction_id,
-				       unsigned int pending);
-
-unsigned int
-TALER_MERCHANTDB_checkout_create (PGconn *conn,
-                             struct GNUNET_CRYPTO_rsa_PublicKey *coin_pub,
-                             uint64_t transaction_id,
-                             struct TALER_Amount *amount,
-                             struct GNUNET_CRYPTO_rsa_Signature *coin_sig);
-
-
-long long
-TALER_MERCHANTDB_checkout_get_product (PGconn *conn,
-                                  struct GNUNET_CRYPTO_rsa_PublicKey *coin_pub);
-
-/**
- * The query gets a contract's nounce and edate used to reproduce
- * a 'wire' JSON object. This function is also useful to check whether
- * a claimed contract existed or not.
- *
- * @param conn handle to the DB
- * @param h_contract the parameter for the row to match against
- * @param nounce where to store the found nounce
- * @param edate where to store the found expiration date
- * @return #GNUNET_OK on success, #GNUNET_SYSERR upon errors
- */
-uint32_t
-TALER_MERCHANTDB_contract_get_values (PGconn *conn,
-                                 const struct GNUNET_HashCode *h_contract,
-                                 uint64_t *nounce,
-				 struct GNUNET_TIME_Absolute *edate);
-
 #endif  /* MERCHANT_DB_H */
 
-/**
- * Get a set of values representing a contract. This function is meant
- * to obsolete the '_get_contract_values' version.
- *
- * @param h_contract the hashcode of this contract
- * @param contract_handle where to store the results
- * @raturn #GNUNET_OK in case of success, #GNUNET_SYSERR
- * upon errors
- */
-uint32_t
-TALER_MERCHANTDB_contract_get_handle (PGconn *conn,
-                                 const struct GNUNET_HashCode *h_contract,
-				 struct TALER_MERCHANTDB_ContractHandle *contract_handle);
-
-/**
- * Store a deposit permission in DB. To be mainly used if /deposit should
- * be retried; also, the merchant can benefit from this information in case
- * he needs to later investigate about some transaction_id.
- * @param conn DB handle
- * @param transaction_id identification number of this payment (which is the
- * same id of the related contract)
- * @param pending if true, this payment got to a persistent state
- * @param which mint is to get this deposit permission
- * @return #GNUNET_OK if successful, #GNUNET_SYSERR upon errors
- */
-uint32_t
-TALER_MERCHANTDB_deposit_permission_store (PGconn *conn,
-                                      const char *deposit_permission,
-				      uint64_t transaction_id,
-				      unsigned int pending,
-				      const char *mint_url);
-/* end of merchant-db.h */
+/* end of taler_merchantdb_lib.h */