added support for Model migrations

now we have a table core.migration and each model (User, Group, Item, ItemContent and a new Migration) have its own
row in the table with a version number

added to config:
db_make_migration_if_needed and db_stop_if_migration_fails (need description yet)

winixd/models/itemcontent.cpp

@@ -165,5 +165,98 @@ bool ItemContent::CanContentBeHtmlFiltered()
 }
 
 
+
+bool ItemContent::do_migration(int & current_table_version)
+{
+	bool ok = true;
+
+	ok = ok && morm::Model::do_migration(current_table_version, 1, this, &ItemContent::do_migration_to_1);
+	ok = ok && morm::Model::do_migration(current_table_version, 2, this, &ItemContent::do_migration_to_2);
+	ok = ok && morm::Model::do_migration(current_table_version, 3, this, &ItemContent::do_migration_to_3);
+
+	return ok;
+}
+
+
+bool ItemContent::do_migration_to_1()
+{
+	const char * str = R"sql(
+		CREATE TABLE core.content (
+			id serial,
+			content text,
+			content_type smallint,
+			file_path character varying(2048),
+			file_fs smallint,
+			file_type smallint,
+			has_thumb smallint,
+			ref integer,
+			modify_index smallint,
+			hash character varying(255),
+			hash_type smallint,
+			file_size bigint
+		);
+	)sql";
+
+	db_query(str);
+	return true;  // IMPROVEME remove me in the future: this is only for a moment until we do migration on all our sites
+}
+
+
+bool ItemContent::do_migration_to_2()
+{
+	const char * str = R"sql(
+		alter table core.content
+		add column user_id integer,
+		add column group_id integer,
+		add column guest_name character varying(20),
+		add column modification_user_id integer,
+		add column privileges integer,
+		add column date_creation timestamp without time zone,
+		add column date_modification timestamp without time zone,
+		add column link_to character varying(2048),
+		add column link_redirect smallint,
+		add column meta text,
+		add column meta_admin text,
+		add column content_parsed text,
+		add column content_parsed_type smallint;
+	)sql";
+
+	return db_query(str);
+}
+
+
+bool ItemContent::do_migration_to_3()
+{
+	const char * str[] = {
+		"alter table core.content rename column ref to \"references\";",
+		"alter table core.content rename column content to content_raw;",
+		"alter table core.content rename column content_type to content_raw_type;",
+		"alter table core.content rename column has_thumb to file_has_thumb;",
+		"alter table core.content rename column hash to file_hash;",
+		"alter table core.content rename column hash_type to file_hash_type;",
+
+		"alter table core.content drop column modify_index;",
+
+		"alter table core.content add column file_has_thumb_new boolean;",
+		"update core.content as c1 set file_has_thumb_new = (select case when file_has_thumb <> 0 then true else false end from core.content as c2 where c1.id = c2.id);",
+		"alter table core.content drop column file_has_thumb;",
+		"alter table core.content rename file_has_thumb_new to file_has_thumb;",
+	};
+
+	size_t len = sizeof(str) / sizeof(const char*);
+
+	for(size_t i=0 ; i < len ; ++i)
+	{
+		if( !db_query(str[i]) )
+		{
+			return false;
+		}
+	}
+
+	return true;
+}
+
+
+
 } // namespace Winix