Add methods to manage access policies

[gothub]

Additional access policy management methods are needed to allow easily modifying a fully constructed DataPackage, or any of its components, e.g. DataObject, SystemMetadata.

Methods are/will be written to 'pass through' to lower level calls as necessary, e.g. DataObject addAccessRule() calls SystemMetadata addAccessRule(). Existing and planned methods are shown here, with new methods marked in bold italics. (sigh! GFM doesn't allow HTML font color).

SystemMetadata.R:

• addAccessRule(SystemMetadata, subject, accessType)
  • add the specified "subject", "accessType" to the access policy
• hasAccessRule(SystemMetadata, subject, accessType)
  • tests if the specified "subject" has the specified access in the sysmeta access policy
• clearAccessPolicy(SystemMetadata)
  • removes all access rules from the access policy
• [x] removeAccessRule(SystemMetadata, subject, accessType)
  • deletes the specified "subject", "accessType" combination from the access policy

DataObject.R

• addAccessRule(DataObject, subject, accessType)
  • adds the specified "subject", "accessType" to the access policies for the DataObject
• [x] hasAccessRule(DataObject, subject, accessType)
  • returns TRUE if the DataObject access policy contains the specify "subject" "accessType" pair
• [x] clearAccessPolicy(DataObject)
  • removes all access rules from the access policy for the DataObject
• setPublicAccess(DataObject)
  • adds "public", "read" to the DataObject access policy
• [x] removeAccessRule(DataObject, subject, accessType)
  • deletes the specified "subject", "accessType" combination from the access policy
• canRead(DataObject, subject)
  • tests if the specified "subject" has read access to the object

DataPackage.R

• [x] addAccessRule(DataPackage, subject, accessType, identifiers)
  • adds the specified "subject", "accessType" to the access policies for DataObjects in the 'identifiers' list, default is all DataObjects in package
• [x] hasAccessRule(DataPackage, subject, accessType, identifiers)
  • returns list of identifiers for DataObjects that have the rule. Checks all DataObjects in 'identifiers' list, default is to check all DataObjects
• [x] clearAccessPolicy(DataPackage, identifiers)
  • removes all access rules for all DataObjects in 'identifiers' list, default is all DataObjects
• [x] setPublicAccess(DataPackage, identifiers)
  • adds "public", "read" to all DataObjects in 'identifiers list, default is all DataObjects
• [x] removeAccessRule(DataPackage, subject, accessType, identifiers)
  • removes the specified "subject", "accessType" from accessPolicy for all DataObjects in identifiers, default is all DataObjects in package

[gothub]

Completed in commits 1dd6f32037d7ea947c1fb7ad0c465ae67102ef02 through 720f9754686da0f8f884270b84b06599546d658c