pg_get__*_ddl consolidation

Greetings

Euler Taveira and I have been working on consolidating these patches.

These patches came out of a suggestion from me some time back [1], and I
used it as the base for some work at an EDB internal program. Perhaps I
was motivated a bit by Mao's dictum "Let a hundred flowers bloom; let a
hundred schools of thought contend." I wanted to see what people would
come up with. Therefore, if this has seemed a bit chaotic, I apologize,
both to the authors and to the list. I won't do things quite this way in
future.

Rather than adding to the already huge ruleutils.c, we decided to create
a new ddlutils.c file to contain these functions and their associated
infrastructure. There is in fact a fairly clean separation between these
functions and ruleutils. We just need to expose one function in ruleutils.

We (Euler and I) decided to concentrate on setting up common
infrastucture and ensuring a common argument and result structure. In
this first round, we are proposing to add functions for getting the DDL
for databases, tablespaces, and roles. We decided to stop there for now.
This sets up a good basis for dealing with more object types in future.
To the authors of the remaining patches - rest assured you have not been
forgotten.

Patch 1 sets up the functions used by the rest for option parsing. see [2]
Patch 2 implements pg_get_role_dll see[3]
Patch 3 implements pg_get_tabespace_ddl see [4]
Patch 4 implements pg_get_database_ddl see [2]

cheers

andrew

[1]
https://www.postgresql.org/message-id/flat/945db7c5-be75-45bf-b55b-cb1e56f2e3e9%40dunslane.net

[2]
https://www.postgresql.org/message-id/flat/CANxoLDc6FHBYJvcgOnZyS+jF0NUo3Lq_83-rttBuJgs9id_UDg(at)mail(dot)gmail(dot)com

[3]
https://www.postgresql.org/message-id/flat/4c5f895e-3281-48f8-b943-9228b7da6471(at)gmail(dot)com

[4]
https://www.postgresql.org/message-id/flat/CAKWEB6rmnmGKUA87Zmq-s=b3Scsnj02C0kObQjnbL2ajfPWGEw(at)mail(dot)gmail(dot)com

--
Andrew Dunstan
EDB: https://www.enterprisedb.com