[9/50] git commit: Simplify LuaRemapIndex somewhat

[jp...@apache.org]

Simplify LuaRemapIndex somewhat


Project: http://git-wip-us.apache.org/repos/asf/trafficserver/repo
Commit: http://git-wip-us.apache.org/repos/asf/trafficserver/commit/1dd587c6
Tree: http://git-wip-us.apache.org/repos/asf/trafficserver/tree/1dd587c6
Diff: http://git-wip-us.apache.org/repos/asf/trafficserver/diff/1dd587c6

Branch: refs/heads/jpeach/lua
Commit: 1dd587c615ba128959e0d38b7bd174f0c44b81f3
Parents: 5eb5f22
Author: James Peach <jp...@apache.org>
Authored: Mon Apr 23 22:00:19 2012 -0700
Committer: James Peach <jp...@apache.org>
Committed: Tue Jun 12 08:48:38 2012 -0700

----------------------------------------------------------------------
 plugins/lua/lapi.cc |   38 +++++++++++++++++++++++---------------
 1 files changed, 23 insertions(+), 15 deletions(-)
----------------------------------------------------------------------


http://git-wip-us.apache.org/repos/asf/trafficserver/blob/1dd587c6/plugins/lua/lapi.cc
----------------------------------------------------------------------
diff --git a/plugins/lua/lapi.cc b/plugins/lua/lapi.cc
index a621408..ad956ee 100644
--- a/plugins/lua/lapi.cc
+++ b/plugins/lua/lapi.cc
@@ -243,6 +243,12 @@ LuaRemapUrl(lua_State * lua)
   return 1;
 }
 
+// Since we cannot add fields to userdata objects, we use the environment to store the fields. If the requested
+// field isn't in our metatable, try to find it in the environment. Populate keys in the environment on demand if
+// the request is for a key that we know about.
+//
+// XXX When we set __index in the metatable, Lua routes all method calls through here rather than checking for the
+// existing key first. That's a bit surprising and I wonder whether there's a better way to handle this.
 static int
 LuaRemapIndex(lua_State * lua)
 {
@@ -254,9 +260,6 @@ LuaRemapIndex(lua_State * lua)
 
   TSDebug("lua", "%s[%s]", __func__, index);
 
-  // XXX When we set __index in the metatable, Lua routes all method calls through here rather than checking for the
-  // existing key first. That's a bit surprising and I wonder whether there's a better way to handle this.
-
   // Get the userdata's metatable and look up the index in it.
   lua_getmetatable(lua, 1);
   lua_getfield(lua, -1, index);
@@ -269,32 +272,37 @@ LuaRemapIndex(lua_State * lua)
   // Pop the field value and the metatable.
   lua_pop(lua, 2);
 
-  if (strcmp(index, "headers") != 0) {
-    return 0;
-  }
-
   lua_getfenv(lua, 1);
-  TSDebug("lua", "-1 is %s", LTYPEOF(lua, -1));
 
   // Get the requested field from the environment table.
   lua_getfield(lua, -1, index);
-  if (lua_isnoneornil(lua, -1)) {
+
+  // If we have a value for that field, pop the environment table, leaving the value on top.
+  if (!lua_isnoneornil(lua, -1)) {
+    lua_remove(lua, -2);
+    return 1;
+  }
+
+  // Pop the nil field value.
+  lua_pop(lua, 1);
+
+  if (strcmp(index, "headers") == 0) {
     LuaRemapHeaders * hdrs;
-    TSDebug("lua", "populating '%s' field", index);
-    lua_pop(lua, 1);
 
     hdrs = LuaRemapHeaders::alloc(lua);
     hdrs->buffer = rq->rri->requestBufp;
     hdrs->headers = rq->rri->requestHdrp;
 
-    // Set it for the 'headers' index and push it on the stack.
+    // Set it for the 'headers' index and then push it on the stack.
     lua_setfield(lua, -2, index);
     lua_getfield(lua, -1, index);
+
+    // Pop the environment table, leaving the field value on top.
+    lua_remove(lua, -2);
+    return 1;
   }
 
-  // Pop the environment table, leaving the field value on top.
-  lua_remove(lua, -2);
-  return 1;
+  return 0;
 }
 
 static const luaL_Reg RRI[] =