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authordaurnimator <quae@daurnimator.com>2017-05-23 14:31:31 +1000
committerdaurnimator <quae@daurnimator.com>2017-05-23 15:06:33 +1000
commitdbb25922aad020bcf898c08e809811641561cd87 (patch)
treeb35a45434ac221f36b23f4f87e3775ccb6f56543
parentb2fb7a9302693fe5e164469eedb802b54e460347 (diff)
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src/ltable.js: Implement table_hash for lightuserdata
-rw-r--r--src/lstring.js3
-rw-r--r--src/ltable.js42
2 files changed, 43 insertions, 2 deletions
diff --git a/src/lstring.js b/src/lstring.js
index 1887e85..a5ee669 100644
--- a/src/lstring.js
+++ b/src/lstring.js
@@ -27,7 +27,8 @@ const luaS_eqlngstr = function(a, b) {
return a == b || (a.realstring.length == b.realstring.length && a.realstring.join() == b.realstring.join());
};
-/* converts strings (arrays) to a consistent map key */
+/* converts strings (arrays) to a consistent map key
+ make sure this doesn't conflict with any of the anti-collision strategies in ltable */
const luaS_hash = function(str) {
assert(Array.isArray(str));
return str.map(e => `${e}|`).join('');
diff --git a/src/ltable.js b/src/ltable.js
index c8bf7a2..88b09e3 100644
--- a/src/ltable.js
+++ b/src/ltable.js
@@ -7,8 +7,20 @@ const defs = require('./defs.js');
const ldebug = require('./ldebug.js');
const lobject = require('./lobject.js');
const lstring = require('./lstring.js');
+const lstate = require('./lstate.js');
const CT = defs.constant_types;
+/* used to prevent conflicts with lightuserdata keys */
+let lightuserdata_hashes = new WeakMap();
+const get_lightuserdata_hash = function(v) {
+ let hash = lightuserdata_hashes.get(v);
+ if (!hash) {
+ hash = Symbol("lightuserdata");
+ lightuserdata_hashes.set(v, hash);
+ }
+ return hash;
+};
+
const table_hash = function(L, key) {
switch(key.type) {
case CT.LUA_TNIL:
@@ -18,7 +30,6 @@ const table_hash = function(L, key) {
return ldebug.luaG_runerror(L, defs.to_luastring("table index is NaN", true));
/* fall through */
case CT.LUA_TBOOLEAN:
- case CT.LUA_TLIGHTUSERDATA: /* XXX: if user pushes conflicting lightuserdata then the table will do odd things */
case CT.LUA_TNUMINT:
case CT.LUA_TTABLE:
case CT.LUA_TLCL:
@@ -30,6 +41,35 @@ const table_hash = function(L, key) {
case CT.LUA_TSHRSTR:
case CT.LUA_TLNGSTR:
return lstring.luaS_hashlongstr(key.tsvalue());
+ case CT.LUA_TLIGHTUSERDATA:
+ let v = key.value;
+ switch(typeof v) {
+ case "string":
+ /* possible conflict with LUA_TSTRING.
+ prefix this string with "*" so they don't clash */
+ return "*" + v;
+ case "number":
+ /* possible conflict with LUA_TNUMBER.
+ turn into string and prefix with "#" to avoid clash with other strings */
+ return "#" + v;
+ case "boolean":
+ /* possible conflict with LUA_TBOOLEAN. use strings ?true and ?false instead */
+ return v?"?true":"?false";
+ case "function":
+ /* possible conflict with LUA_TLCF.
+ indirect via a weakmap */
+ return get_lightuserdata_hash(v);
+ case "object":
+ /* v shouldn't be a CClosure, LClosure, Table or Userdata from this state as they're never exposed
+ the only exposed internal type is a lua_State */
+ if (v instanceof lstate.lua_State && v.l_G === L.l_G) {
+ /* indirect via a weakmap */
+ return get_lightuserdata_hash(v);
+ }
+ /* fall through */
+ default:
+ return v;
+ }
default:
throw new Error("unknown key type: " + key.type);
}