Ubercart Addresses field handler API: Fields should specify their data type

This a subissue of #1831424: Turn Ubercart Addresses address into an entity.

Problem/Motivation

The Entity API module provides a hook called hook_entity_property_info() with which metadata about entity properties can be defined. Ubercart Addresses provides the hook hook_uc_addresses_fields() with which address fields can be registered. As each address field of an address is essentially a property of the upcoming address entity, it would be nice if property metadata can be defined in hook_uc_addresses_fields(), so modules that register address fields don't need to implement hook_entity_property_info() as well to define additional or similar information about their fields.

One metadata item is the data type of the field, simply called 'type'. This can be 'text', 'integer', 'boolean', etc. So, in preparation of the entity integration, it would be nice if the data type is declared for each field, which will fallback to 'text' for if it's not defined.

Affected versions

Though it would only have a function for the 7.x-1.x version, fields specifying their data types will also be implemented for the 6.x-2.x version for consistency (and the information *could* be useful for modules extending Ubercart Addresses as well).

Conflicts

The Ubercart Addresses Example module already used the 'type' property to define the database data type. The example module should be adjusted to remain compatible with future changes (Entity API integration).

Proposed resolution

Current registered address fields will get an extra property called 'type'. This will be mapped to Entity API property info later on. Optionally, other properties could be defined as documented by hook_entity_property_info().

Remaining tasks

• Define data types for each registered address field that should not be just text.
• Provide the default value 'text' for property 'type' in uc_addresses_get_address_fields().
• Adjust Ubercart Addresses Example module. Fixed in #1911136: Ubercart Addresses Example module: separate schema definitions from field handler API definitions.

User interface changes

None.

API changes

Modules registering address fields should from now on define the data type of their fields if it's not supposed to be just text. Optionally, they can define other properties as documented by hook_entity_property_info().

I'm working on it.