result_view() now reuses same metatable instance for every table.

1 files changed, 51 insertions, 46 deletions

diff --git a/indra/newview/scripts/lua/require/result_view.lua b/indra/newview/scripts/lua/require/result_view.lua
index d53d953c24..c719681c66 100644
--- a/indra/newview/scripts/lua/require/result_view.lua
+++ b/indra/newview/scripts/lua/require/result_view.lua
@@ -1,3 +1,50 @@
+-- metatable for every result_view() table
+local mt = {
+    __len = function(this)
+        return this.length
+    end,
+    __index = function(this, i)
+        -- right away, convert to 0-relative indexing
+        i -= 1
+        -- can we find this index within the current slice?
+        local reli = i - this.start
+        if 0 <= reli and reli < #this.slice then
+            -- Lua 1-relative indexing
+            return this.slice[reli + 1]
+        end
+        -- is this index outside the overall result set?
+        if not (0 <= i and i < this.length) then
+            return nil
+        end
+        -- fetch a new slice starting at i, using provided fetch()
+        local start
+        this.slice, start = this.fetch(this.key, i)
+        -- It's possible that caller-provided fetch() function forgot
+        -- to return the adjusted start index of the new slice. In
+        -- Lua, 0 tests as true, so if fetch() returned (slice, 0),
+        -- we'll duly reset this.start to 0. Otherwise, assume the
+        -- requested index was not adjusted: that the returned slice
+        -- really does start at i.
+        this.start = start or i
+        -- Hopefully this slice contains the desired i.
+        -- Back to 1-relative indexing.
+        return this.slice[i - this.start + 1]
+    end,
+    -- We purposely avoid putting any array entries (int keys) into
+    -- our table so that access to any int key will always call our
+    -- __index() metamethod. Moreover, we want any table iteration to
+    -- call __index(table, i) however many times; we do NOT want it to
+    -- retrieve key, length, start, slice.
+    -- So turn 'for k, v in result' into 'for k, v in ipairs(result)'.
+    __iter = ipairs,
+    -- This result set provides read-only access.
+    -- We do not support pushing updates to individual items back to
+    -- C++; for the intended use cases, that makes no sense.
+    __newindex = function(this, i, value)
+        error("result_view is a read-only data structure", 2)
+    end
+}
+
 -- result_view(key_length, fetch) returns a table which stores only a slice
 -- of a result set plus some control values, yet presents read-only virtual
 -- access to the entire result set.
@@ -11,53 +58,11 @@ local function result_view(key_length, fetch)
             -- C++ result sets use 0-based indexing, so internally we do too
             start=0,
             -- start with a dummy array with length 0
-            slice={}
+            slice={},
+            fetch=fetch
         },
-        {
-            __len = function(this)
-                return this.length
-            end,
-            __index = function(this, i)
-                -- right away, convert to 0-relative indexing
-                i -= 1
-                -- can we find this index within the current slice?
-                local reli = i - this.start
-                if 0 <= reli and reli < #this.slice then
-                    -- Lua 1-relative indexing
-                    return this.slice[reli + 1]
-                end
-                -- is this index outside the overall result set?
-                if not (0 <= i and i < this.length) then
-                    return nil
-                end
-                -- fetch a new slice starting at i, using provided fetch()
-                local start
-                this.slice, start = fetch(this.key, i)
-                -- It's possible that caller-provided fetch() function forgot
-                -- to return the adjusted start index of the new slice. In
-                -- Lua, 0 tests as true, so if fetch() returned (slice, 0),
-                -- we'll duly reset this.start to 0. Otherwise, assume the
-                -- requested index was not adjusted: that the returned slice
-                -- really does start at i.
-                this.start = start or i
-                -- Hopefully this slice contains the desired i.
-                -- Back to 1-relative indexing.
-                return this.slice[i - this.start + 1]
-            end,
-            -- We purposely avoid putting any array entries (int keys) into
-            -- our table so that access to any int key will always call our
-            -- __index() metamethod. Moreover, we want any table iteration to
-            -- call __index(table, i) however many times; we do NOT want it to
-            -- retrieve key, length, start, slice.
-            -- So turn 'for k, v in result' into 'for k, v in ipairs(result)'.
-            __iter = ipairs,
-            -- This result set provides read-only access.
-            -- We do not support pushing updates to individual items back to
-            -- C++; for the intended use cases, that makes no sense.
-            __newindex = function(this, i, value)
-                error("result_view is a read-only data structure", 2)
-            end
-        }
+        -- use our special metatable
+        mt
     )
 end