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-rw-r--r--src/lindafactory.cpp136
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1/*
2 * LINDAFACTORY.CPP Copyright (c) 2024-, Benoit Germain
3 *
4 * Linda deep userdata factory
5*/
6
7/*
8===============================================================================
9
10Copyright (C) 2024- benoit Germain <bnt.germain@gmail.com>
11
12Permission is hereby granted, free of charge, to any person obtaining a copy
13of this software and associated documentation files (the "Software"), to deal
14in the Software without restriction, including without limitation the rights
15to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
16copies of the Software, and to permit persons to whom the Software is
17furnished to do so, subject to the following conditions:
18
19The above copyright notice and this permission notice shall be included in
20all copies or substantial portions of the Software.
21
22THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
23IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
24FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
25AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
26LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
27OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
28THE SOFTWARE.
29
30===============================================================================
31*/
32
33#include "lindafactory.h"
34
35#include "linda.h"
36
37// #################################################################################################
38
39void LindaFactory::createMetatable(lua_State* L_) const
40{
41 STACK_CHECK_START_REL(L_, 0);
42 lua_newtable(L_);
43 // metatable is its own index
44 lua_pushvalue(L_, -1);
45 lua_setfield(L_, -2, "__index");
46
47 // protect metatable from external access
48 lua_pushliteral(L_, "Linda");
49 lua_setfield(L_, -2, "__metatable");
50
51 // the linda functions
52 luaL_setfuncs(L_, mLindaMT, 0);
53
54 // some constants
55 kLindaBatched.pushKey(L_);
56 lua_setfield(L_, -2, "batched");
57
58 kNilSentinel.pushKey(L_);
59 lua_setfield(L_, -2, "null");
60
61 STACK_CHECK(L_, 1);
62}
63
64// #################################################################################################
65
66void LindaFactory::deleteDeepObjectInternal(lua_State* L_, DeepPrelude* o_) const
67{
68 Linda* const linda{ static_cast<Linda*>(o_) };
69 LUA_ASSERT(L_, linda);
70 Keeper* const myK{ linda->whichKeeper() };
71 // if collected after the universe, keepers are already destroyed, and there is nothing to clear
72 if (myK)
73 {
74 // if collected from my own keeper, we can't acquire/release it
75 // because we are already inside a protected area, and trying to do so would deadlock!
76 bool const need_acquire_release{ myK->L != L_ };
77 // Clean associated structures in the keeper state.
78 Keeper* const K{ need_acquire_release ? linda->acquireKeeper() : myK };
79 // hopefully this won't ever raise an error as we would jump to the closest pcall site while forgetting to release the keeper mutex...
80 [[maybe_unused]] KeeperCallResult const result{ keeper_call(linda->U, K->L, KEEPER_API(clear), L_, linda, 0) };
81 LUA_ASSERT(L_, result.has_value() && result.value() == 0);
82 if (need_acquire_release)
83 {
84 linda->releaseKeeper(K);
85 }
86 }
87
88 delete linda; // operator delete overload ensures things go as expected
89}
90
91// #################################################################################################
92
93char const* LindaFactory::moduleName() const
94{
95 // linda is a special case because we know lanes must be loaded from the main lua state
96 // to be able to ever get here, so we know it will remain loaded as long a the main state is around
97 // in other words, forever.
98 return nullptr;
99}
100
101// #################################################################################################
102
103DeepPrelude* LindaFactory::newDeepObjectInternal(lua_State* L_) const
104{
105 size_t name_len{ 0 };
106 char const* linda_name{ nullptr };
107 LindaGroup linda_group{ 0 };
108 // should have a string and/or a number of the stack as parameters (name and group)
109 switch (lua_gettop(L_))
110 {
111 default: // 0
112 break;
113
114 case 1: // 1 parameter, either a name or a group
115 if (lua_type(L_, -1) == LUA_TSTRING)
116 {
117 linda_name = lua_tolstring(L_, -1, &name_len);
118 }
119 else
120 {
121 linda_group = LindaGroup{ static_cast<int>(lua_tointeger(L_, -1)) };
122 }
123 break;
124
125 case 2: // 2 parameters, a name and group, in that order
126 linda_name = lua_tolstring(L_, -2, &name_len);
127 linda_group = LindaGroup{ static_cast<int>(lua_tointeger(L_, -1)) };
128 break;
129 }
130
131 // The deep data is allocated separately of Lua stack; we might no longer be around when last reference to it is being released.
132 // One can use any memory allocation scheme. Just don't use L's allocF because we don't know which state will get the honor of GCing the linda
133 Universe* const U{ universe_get(L_) };
134 Linda* const linda{ new (U) Linda{ U, linda_group, linda_name, name_len } };
135 return linda;
136}