Refectoring transaction handling

include/cgimap/backend/apidb/changeset.hpp

@@ -20,8 +20,6 @@ struct changeset {
   changeset(bool dp, const std::string &dn, osm_user_id_t id);
 };
 
-changeset *fetch_changeset(pqxx::transaction_base &w,  osm_changeset_id_t id);
-
 std::map<osm_changeset_id_t, changeset *> fetch_changesets(pqxx::transaction_base &w,  std::set<osm_changeset_id_t> id);
 
 

include/cgimap/backend/apidb/pgsql_update.hpp

@@ -13,7 +13,7 @@
 class pgsql_update : public data_update {
 
 public:
-  pgsql_update(pqxx::connection &conn, bool is_readonly);
+  pgsql_update(Transaction_Owner_Base& to, bool is_readonly);
 
   ~pgsql_update();
 
@@ -41,7 +41,8 @@ class pgsql_update : public data_update {
   public:
     factory(const boost::program_options::variables_map &);
     virtual ~factory();
-    virtual std::shared_ptr<data_update> make_data_update();
+    virtual std::shared_ptr<data_update> make_data_update(Transaction_Owner_Base& to);
+    virtual std::unique_ptr<Transaction_Owner_Base> get_default_transaction();
 
   private:
     pqxx::connection m_connection;

include/cgimap/backend/apidb/readonly_pgsql_selection.hpp

@@ -4,6 +4,8 @@
 #include "cgimap/data_selection.hpp"
 #include "cgimap/backend/apidb/changeset.hpp"
 #include "cgimap/backend/apidb/cache.hpp"
+#include "cgimap/backend/apidb/transaction_manager.hpp"
+
 #include <pqxx/pqxx>
 #include <boost/program_options.hpp>
 #include <chrono>
@@ -19,7 +21,7 @@
  */
 class readonly_pgsql_selection : public data_selection {
 public:
-  readonly_pgsql_selection(pqxx::connection &conn,
+  readonly_pgsql_selection(Transaction_Owner_Base& to,
                            cache<osm_changeset_id_t, changeset> &changeset_cache);
   ~readonly_pgsql_selection();
 
@@ -72,7 +74,8 @@ class readonly_pgsql_selection : public data_selection {
   public:
     factory(const boost::program_options::variables_map &);
     virtual ~factory();
-    virtual std::shared_ptr<data_selection> make_selection();
+    virtual std::shared_ptr<data_selection> make_selection(Transaction_Owner_Base& );
+    virtual std::unique_ptr<Transaction_Owner_Base> get_default_transaction();
 
   private:
     pqxx::connection m_connection, m_cache_connection;
@@ -82,10 +85,6 @@ class readonly_pgsql_selection : public data_selection {
   };
 
 private:
-  // the transaction in which the selection takes place. this is
-  // fully read-only, and cannot create any temporary tables,
-  // unlike writeable_pgsql_selection.
-  pqxx::work w;
 
   // true if we want to include changeset discussions along with
   // the changesets themselves. defaults to false.
@@ -100,6 +99,8 @@ class readonly_pgsql_selection : public data_selection {
   std::set<osm_nwr_id_t> sel_nodes, sel_ways, sel_relations;
   std::set<osm_edition_t> sel_historic_nodes, sel_historic_ways, sel_historic_relations;
   cache<osm_changeset_id_t, changeset> &cc;
+
+  Transaction_Manager m;
 };
 
 #endif /* READONLY_PGSQL_SELECTION_HPP */

include/cgimap/backend/apidb/transaction_manager.hpp

@@ -7,10 +7,55 @@
 #include <boost/format.hpp>
 #include <pqxx/pqxx>
 
+#include <iostream>
+
+
+class Transaction_Owner_Base
+{
+public:
+  Transaction_Owner_Base() {}
+  virtual pqxx::transaction_base& get_transaction() = 0;
+  virtual ~Transaction_Owner_Base() {}
+};
+
+
+class Transaction_Owner_ReadOnly : public Transaction_Owner_Base
+{
+public:
+  explicit Transaction_Owner_ReadOnly(pqxx::connection &conn);
+  virtual pqxx::transaction_base& get_transaction();
+  ~Transaction_Owner_ReadOnly() {}
+
+private:
+  pqxx::read_transaction m_txn;
+};
+
+
+class Transaction_Owner_ReadWrite : public Transaction_Owner_Base
+{
+public:
+  explicit Transaction_Owner_ReadWrite(pqxx::connection &conn);
+  virtual pqxx::transaction_base& get_transaction();
+  ~Transaction_Owner_ReadWrite() {}
+
+private:
+  pqxx::work m_txn;
+};
+
+class Transaction_Owner_Void : public Transaction_Owner_Base
+{
+public:
+  explicit Transaction_Owner_Void();
+  virtual pqxx::transaction_base& get_transaction();
+  ~Transaction_Owner_Void() {}
+};
+
+
+
 class Transaction_Manager {
 
 public:
-  explicit Transaction_Manager(pqxx::connection &conn);
+  explicit Transaction_Manager(Transaction_Owner_Base &to);
 
   void prepare(const std::string &name, const std::string &);
 
@@ -55,7 +100,8 @@ class Transaction_Manager {
     return (pass_param<Args...>(in(std::forward<Arg>(arg)), std::forward<Args>(args)...));
   }
 
-  pqxx::work m_txn;
+  pqxx::transaction_base & m_txn;
 };
 
+
 #endif

include/cgimap/data_selection.hpp

@@ -3,6 +3,7 @@
 
 #include "cgimap/types.hpp"
 #include "cgimap/output_formatter.hpp"
+#include "cgimap/backend/apidb/transaction_manager.hpp"
 
 #include <chrono>
 #include <memory>
@@ -166,7 +167,9 @@ class data_selection {
 
     /// get a handle to a selection which can be used to build up
     /// a working set of data.
-    virtual std::shared_ptr<data_selection> make_selection() = 0;
+    virtual std::shared_ptr<data_selection> make_selection(Transaction_Owner_Base&) = 0;
+
+    virtual std::unique_ptr<Transaction_Owner_Base> get_default_transaction() = 0;
   };
 };
 

include/cgimap/data_update.hpp

@@ -10,6 +10,8 @@
 #include "cgimap/api06/changeset_upload/relation_updater.hpp"
 #include "cgimap/api06/changeset_upload/way_updater.hpp"
 
+#include "cgimap/backend/apidb/transaction_manager.hpp"
+
 #include <memory>
 #include <vector>
 
@@ -47,7 +49,9 @@ class data_update {
 
     /// get a handle to a selection which can be used to build up
     /// a working set of data.
-    virtual std::shared_ptr<data_update> make_data_update() = 0;
+    virtual std::shared_ptr<data_update> make_data_update(Transaction_Owner_Base&) = 0;
+
+    virtual std::unique_ptr<Transaction_Owner_Base> get_default_transaction() = 0;
   };
 };
 

src/backend/apidb/changeset.cpp

@@ -19,6 +19,10 @@ std::map<osm_changeset_id_t, changeset *> fetch_changesets(pqxx::transaction_bas
   if (ids.empty())
     return result;
 
+  w.conn().prepare("extract_changeset_userdetails",
+      "SELECT c.id, u.data_public, u.display_name, u.id from users u "
+                   "join changesets c on u.id=c.user_id where c.id = ANY($1)");
+
   pqxx::result res =
       w.prepared("extract_changeset_userdetails")(ids).exec();
 

src/backend/apidb/pgsql_update.cpp

@@ -58,8 +58,8 @@ std::string connect_db_str(const po::variables_map &options) {
 } // anonymous namespace
 
 pgsql_update::pgsql_update(
-    pqxx::connection &conn, bool readonly)
-    : m{ conn }, m_readonly{ readonly } {
+    Transaction_Owner_Base& to, bool readonly)
+    : m{ to }, m_readonly{ readonly } {
 
   if (is_api_write_disabled())
     return;
@@ -167,6 +167,14 @@ pgsql_update::factory::factory(const po::variables_map &opts)
 pgsql_update::factory::~factory() = default;
 
 std::shared_ptr<data_update>
-pgsql_update::factory::make_data_update() {
-  return std::make_shared<pgsql_update>(std::ref(m_connection), m_api_write_disabled);
+pgsql_update::factory::make_data_update(Transaction_Owner_Base& to) {
+  return std::make_shared<pgsql_update>(to, m_api_write_disabled);
 }
+
+std::unique_ptr<Transaction_Owner_Base>
+pgsql_update::factory::get_default_transaction()
+{
+  return std::unique_ptr<Transaction_Owner_ReadWrite>(new Transaction_Owner_ReadWrite(std::ref(m_connection)));
+}
+
+