Unify the value returned by linda:deep() and the string conversion of an unnamed Linda

3 files changed, 20 insertions, 5 deletions

diff --git a/docs/index.html b/docs/index.html
index dd7854a..60f4970 100644
--- a/docs/index.html
+++ b/docs/index.html
@@ -1213,18 +1213,18 @@
 <table border="1" bgcolor="#E0E0FF" cellpadding="10" style="width:50%"><tr><td><pre>
         h = lanes.linda([opt_name, [opt_group]])
 
-        [true|lanes.cancel_error] = h:send([timeout_secs,] key, ...)
+        true|lanes.cancel_error = h:send([timeout_secs,] key, ...)
 
         key, val = h:receive([timeout_secs,] key [, key...])
 
         key, val [, val...] = h:receive(timeout, h.batched, key, n_uint_min[, n_uint_max])
 
-        [true|lanes.cancel_error] = h:limit(key, n_uint)
+        true|lanes.cancel_error = h:limit(key, n_uint)
 </pre></td></tr></table>
 
 <p>
         Converting the Linda to a string will yield the provided name prefixed by <tt>"Linda: "</tt>.<br/>
-        If <tt>opt_name</tt> is omitted, it will evaluate to an hexadecimal number uniquely representing that Linda.<br/>
+        If <tt>opt_name</tt> is omitted, it will evaluate to an hexadecimal number uniquely representing that Linda when the Linda is converted to a string. The value is the same as returned by <tt>linda:deep()</tt>.<br/>
         If <tt>opt_name</tt> is <tt>"auto"</tt>, Lanes will try to construct a name from the source location that called <tt>lanes.linda()</tt>. If that fails, the Linda name will be <tt>"&lt;unresolved&gt;"</tt>.
 </p>
 <p>
@@ -1331,6 +1331,14 @@
         If not void, the lane's cancel status overrides the Linda's cancel status.
 </p>
 
+<table border="1" bgcolor="#E0E0FF" cellpadding="10" style="width:50%"><tr><td><pre>
+        light userdata = h:deep()
+</pre></td></tr></table>
+
+<p>
+        Returns a light userdata that uniquely represents the Linda. The stored value is the same as what is seen when converting an unnamed Linda to a string.
+</p>
+
 <h3 id="keepers">Granularity of using Lindas</h3>
 
 <p>
diff --git a/src/linda.cpp b/src/linda.cpp
index 81926f9..4dc2162 100644
--- a/src/linda.cpp
+++ b/src/linda.cpp
@@ -87,7 +87,7 @@ template <bool OPT>
             std::ignore = luaG_pushstring(L_, _lindaName);
         } else {
             // obfuscate the pointer so that we can't read the value with our eyes out of a script
-            std::ignore = luaG_pushstring(L_, "%p", std::bit_cast<uintptr_t>(_linda) ^ kConfigRegKey.storage);
+            std::ignore = luaG_pushstring(L_, "%p", _linda->obfuscated());
         }
         lua_concat(L_, 2);
         return 1;
@@ -344,7 +344,7 @@ LUAG_FUNC(linda_count)
 LUAG_FUNC(linda_deep)
 {
     Linda* const _linda{ ToLinda<false>(L_, 1) };
-    lua_pushlightuserdata(L_, _linda); // just the address
+    lua_pushlightuserdata(L_, _linda->obfuscated<void*>()); // just the address
     return 1;
 }
 
diff --git a/src/linda.h b/src/linda.h
index 3098161..6901a86 100644
--- a/src/linda.h
+++ b/src/linda.h
@@ -80,6 +80,13 @@ class Linda
     [[nodiscard]] Keeper* acquireKeeper() const;
     [[nodiscard]] std::string_view getName() const;
     [[nodiscard]] bool inKeeperOperation() const { return keeperOperationCount.load(std::memory_order_seq_cst) != 0; }
+    template <typename T = uintptr_t>
+    [[nodiscard]] T obfuscated() const
+    {
+        // xxh64 of string "kObfuscator" generated at https://www.pelock.com/products/hash-calculator
+        static constexpr UniqueKey kObfuscator{ 0x7B8AA1F99A3BD782ull };
+        return std::bit_cast<T>(std::bit_cast<uintptr_t>(this) ^ kObfuscator.storage);
+    };
     void releaseKeeper(Keeper* keeper_) const;
     [[nodiscard]] static int ProtectedCall(lua_State* L_, lua_CFunction f_);
     [[nodiscard]] KeeperOperationInProgress startKeeperOperation(lua_State* const L_) { return KeeperOperationInProgress{ *this, L_ }; };