Realm

1package game
2
3import "chain"
4
5// Roles: one owner, a set of admins, a set of referees.
6//
7//   - The owner manages the admins and the treasury, and can hand the realm
8//     over. The owner is always an admin.
9//   - Admins tune the game and manage the referees.
10//   - Referees are the game servers. They record kills and nothing else.
11
12// callerOf returns the verified caller of a crossing function. rlm must be
13// the cur of the crossing function calling this helper: a stale or forged
14// realm value fails IsCurrent, and Previous is only meaningful on a live one.
15//
16// It takes the realm in second position on purpose, like p/nt/ownable does:
17// a function whose first parameter is a realm is a crossing function.
18func callerOf(_ int, rlm realm) address {
19	if !rlm.IsCurrent() {
20		panic(errSpoofedRealm)
21	}
22	return rlm.Previous().Address()
23}
24
25// assertOwner panics unless the caller is the owner, and returns the caller.
26func assertOwner(_ int, rlm realm) address {
27	caller := callerOf(0, rlm)
28	if !owner.OwnedBy(caller) {
29		panic(errNotOwner)
30	}
31	return caller
32}
33
34// assertAdmin panics unless the caller is an admin, and returns the caller.
35func assertAdmin(_ int, rlm realm) address {
36	caller := callerOf(0, rlm)
37	if !IsAdmin(caller) {
38		panic(errNotAdmin)
39	}
40	return caller
41}
42
43// assertReferee panics unless the caller is a referee, and returns the caller.
44func assertReferee(_ int, rlm realm) address {
45	caller := callerOf(0, rlm)
46	if !IsReferee(caller) {
47		panic(errNotReferee)
48	}
49	return caller
50}
51
52// TransferOwnership hands the realm over to newOwner. Owner only.
53//
54// The previous owner keeps no privilege, unless it was also added to the
55// admin or referee lists.
56func TransferOwnership(cur realm, newOwner address) {
57	// ownable checks the caller and the address. It would take the address
58	// written in capitals though, and an owner under that key could never be
59	// matched to a caller again: see validAddress.
60	if newOwner.IsValid() && !validAddress(newOwner) {
61		panic(errInvalidAddress)
62	}
63	if err := owner.TransferOwnership(0, cur, newOwner); err != nil {
64		panic(err)
65	}
66	bump()
67}
68
69// AddAdmin adds addr to the admin list. Owner only.
70func AddAdmin(cur realm, addr address) {
71	assertOwner(0, cur)
72	if !validAddress(addr) {
73		panic(errInvalidAddress)
74	}
75	if admins.Set(addr.String(), nil) {
76		panic(errAlreadyAdmin)
77	}
78	bump()
79	chain.Emit("AdminAdded", "address", addr.String())
80}
81
82// RemoveAdmin removes addr from the admin list. Owner only.
83//
84// The owner is an admin by definition and cannot be demoted this way, use
85// TransferOwnership.
86func RemoveAdmin(cur realm, addr address) {
87	assertOwner(0, cur)
88	if _, removed := admins.Remove(addr.String()); !removed {
89		panic(errNoSuchAdmin)
90	}
91	bump()
92	chain.Emit("AdminRemoved", "address", addr.String())
93}
94
95// SetTreasury sets the address the sales of skins and planes are forwarded
96// to. Owner only.
97func SetTreasury(cur realm, addr address) {
98	assertOwner(0, cur)
99	if !validAddress(addr) {
100		panic(errInvalidAddress)
101	}
102	// Coins sent to the realm's own address would be stuck: nothing here
103	// ever spends the realm balance.
104	if addr == cur.Address() {
105		panic(errTreasurySelf)
106	}
107	treasury = addr
108	bump()
109	chain.Emit("TreasurySet", "address", addr.String())
110}
111
112// AddReferee allows addr to submit kills. Admin only.
113func AddReferee(cur realm, addr address) {
114	assertAdmin(0, cur)
115	if !validAddress(addr) {
116		panic(errInvalidAddress)
117	}
118	if referees.Set(addr.String(), nil) {
119		panic(errAlreadyReferee)
120	}
121	bump()
122	chain.Emit("RefereeAdded", "address", addr.String())
123}
124
125// RemoveReferee stops addr from submitting kills. Admin only.
126func RemoveReferee(cur realm, addr address) {
127	assertAdmin(0, cur)
128	if _, removed := referees.Remove(addr.String()); !removed {
129		panic(errNoSuchReferee)
130	}
131	bump()
132	chain.Emit("RefereeRemoved", "address", addr.String())
133}
134
135// Owner returns the owner of the realm.
136func Owner() address {
137	return owner.Owner()
138}
139
140// Treasury returns the address the sales of skins and planes are forwarded
141// to.
142func Treasury() address {
143	return treasury
144}
145
146// IsAdmin reports whether addr is an admin. The owner always is.
147func IsAdmin(addr address) bool {
148	return owner.OwnedBy(addr) || admins.Has(addr.String())
149}
150
151// IsReferee reports whether addr may submit kills.
152func IsReferee(addr address) bool {
153	return referees.Has(addr.String())
154}
155