Add CLOB support to Firebird backend

Reuse the existing BLOB support, however we now need to allocate a BLOB
inside firebird_standard_use_type_backend objects as, unlike when using
soci::blob objects, we don't have any way to associate backend-specific
data with the parameter otherwise.

This difference between CLOB and BLOB support is not ideal, but there
doesn't seem to be any way to avoid it.

include/soci/firebird/soci-firebird.h

@@ -59,6 +59,7 @@ enum BuffersType
     eStandard, eVector
 };
 
+struct firebird_blob_backend;
 struct firebird_statement_backend;
 struct firebird_standard_into_type_backend : details::standard_into_type_backend
 {
@@ -117,7 +118,8 @@ struct firebird_vector_into_type_backend : details::vector_into_type_backend
 struct firebird_standard_use_type_backend : details::standard_use_type_backend
 {
     firebird_standard_use_type_backend(firebird_statement_backend &st)
-        : statement_(st), data_(NULL), type_(), position_(0), buf_(NULL), indISCHolder_(0)
+        : statement_(st), data_(NULL), type_(), position_(0), buf_(NULL), indISCHolder_(0),
+          blob_(NULL)
     {}
 
     virtual void bind_by_pos(int &position,
@@ -139,6 +141,9 @@ struct firebird_standard_use_type_backend : details::standard_use_type_backend
 
     char *buf_;
     short indISCHolder_;
+
+    // This is used for types mapping to CLOB.
+    firebird_blob_backend* blob_;
 };
 
 struct firebird_vector_use_type_backend : details::vector_use_type_backend

src/backends/firebird/standard-into-type.cpp

@@ -11,6 +11,8 @@
 #include "firebird/common.h"
 #include "soci/soci.h"
 
+#include <sstream>
+
 using namespace soci;
 using namespace soci::details;
 using namespace soci::details::firebird;
@@ -119,6 +121,28 @@ void firebird_standard_into_type_backend::exchangeData()
                 blob->assign(*reinterpret_cast<ISC_QUAD*>(buf_));
             }
             break;
+
+        case x_longstring:
+            {
+                long_string* const dst = static_cast<long_string*>(data_);
+
+                firebird_blob_backend blob(statement_.session_);
+                blob.assign(*reinterpret_cast<ISC_QUAD*>(buf_));
+
+                std::size_t const len_total = blob.get_len();
+                dst->value.resize(len_total);
+
+                std::size_t len_read = blob.read(0, &dst->value[0], len_total);
+                if (len_read != len_total)
+                {
+                    std::ostringstream os;
+                    os << "Read " << len_read << " bytes instead of expected "
+                       << len_total << " from Firebird text blob object";
+                    throw soci_error(os.str());
+                }
+            }
+            break;
+
         default:
             throw soci_error("Into element used with non-supported type.");
     } // switch

src/backends/firebird/standard-use-type.cpp

@@ -147,6 +147,18 @@ void firebird_standard_use_type_backend::exchangeData()
                 memcpy(buf_, &blob->bid_, var->sqllen);
             }
             break;
+
+        case x_longstring:
+            {
+                long_string const* const src = static_cast<long_string*>(data_);
+
+                blob_ = new firebird_blob_backend(statement_.session_);
+                blob_->append(src->value.c_str(), src->value.length());
+                blob_->save();
+                memcpy(buf_, &blob_->bid_, var->sqllen);
+            }
+            break;
+
         default:
             throw soci_error("Use element used with non-supported type.");
     } // switch
@@ -175,6 +187,13 @@ void firebird_standard_use_type_backend::clean_up()
         delete [] buf_;
         buf_ = NULL;
     }
+
+    if (blob_)
+    {
+        delete blob_;
+        blob_ = NULL;
+    }
+
     std::vector<void*>::iterator it =
         std::find(statement_.uses_.begin(), statement_.uses_.end(), this);
     if (it != statement_.uses_.end())

tests/firebird/test-firebird.cpp

@@ -1274,6 +1274,17 @@ struct TableCreator4 : public tests::table_creator_base
     }
 };
 
+struct TableCreatorCLOB : public tests::table_creator_base
+{
+    TableCreatorCLOB(soci::session & sql)
+            : tests::table_creator_base(sql)
+    {
+        sql << "create table soci_test(id integer, s blob sub_type text)";
+        sql.commit();
+        sql.begin();
+    }
+};
+
 class test_context : public tests::test_context_base
 {
     public:
@@ -1302,6 +1313,11 @@ class test_context : public tests::test_context_base
             return new TableCreator4(s);
         }
 
+        tests::table_creator_base* table_creator_clob(soci::session& s) const
+        {
+            return new TableCreatorCLOB(s);
+        }
+
         std::string to_date_time(std::string const &datdt_string) const
         {
             return "'" + datdt_string + "'";