-- A module that joins has a user and a group of its own, each library has a group of its own, and a library's
-- existing data is taken once, on the operator's word (novox/hq ADR 0328 §3, §4, §7, §15).
--
-- **One sequence for every number the mesh gives.** A joining module is given one number, its user's and its own
-- group's (mesh-<module>); a library is given one, its group's (mesh-<library>). Both are drawn from this sequence, so
-- a module's own group and a library's group never share a number. The range is 50000–59999 (catalogue.IdentityLow and
-- IdentityHigh): above the numbers distributions give people, below the 60000s Debian keeps for its daemons, and
-- nowhere near root's 0 or a root group's (0, 4, 10). The checks refuse a row outside it, so no write, by hand or by a
-- later bug, can make one root's (§15). A sequence never hands a number back, and a row is kept after its module or
-- library is gone, so a number once given is never given to another: a file left owned by a removed module's user is
-- never inherited by a new one.
create sequence mesh_number as integer minvalue 50000 maxvalue 59999 start 50000 no cycle;

create table module_identity (
    module    text        primary key,
    uid       integer     not null unique check (uid between 50000 and 59999),
    allocated timestamptz not null default now()
);

create table library_group (
    library   text        primary key,
    gid       integer     not null unique check (gid between 50000 and 59999),
    allocated timestamptz not null default now()
);

-- **A library taken** (§7). The first time a library's root on its home holds data not yet in its group, the operator
-- is asked once for that library; on the warrant the node-engine sets the group, group write and setgid under the root,
-- and the library is taken: kept from then on without asking. The row is the record of that act — on which machine
-- root and filesystem, who approved it, under which warrant. A library whose home, root or filesystem changed since
-- (it moved to another machine, path or disk) is not taken by that warrant, and the operator is asked again; a new take
-- replaces the row.
create table kept_library (
    library  text        primary key,
    home     text        not null,
    -- The root it was taken at: a library whose root changed since is taken again.
    root     text        not null check (root like '/%'),
    -- The filesystem the root was on when taken, as the engine names it without a path ("fs-<12 hex>"); empty when
    -- the engine named none.
    placed   text        not null default '',
    taken_at timestamptz not null default now(),
    taken_by text        not null,
    ask      text        not null,
    warrant  text        not null,
    -- What the node-engine answered when it started the take.
    said     text        not null default '',
    -- Whether the engine has stated the take's act done under this warrant: only then is the library taken. Until
    -- then the take is under way — the library still waits, and the operator is not asked again — and an act stated
    -- failed forgets the row, so the operator is asked again.
    done     boolean     not null default false
);