Cache expansions

1 files changed, 8 insertions, 0 deletions

diff --git a/lib/gitano/util.lua b/lib/gitano/util.lua
index c2a53a7..291c68d 100644
--- a/lib/gitano/util.lua
+++ b/lib/gitano/util.lua
@@ -337,12 +337,18 @@ end
 
 local tagname_pattern = "^[a-z0-9_%-/]*[a-z0-9_%-]*$"
 
+local cached_expansions = {}
+
 local function prep_expansion(str)
    -- Parse 'str' and return a table representing a sequence of
    -- operations required to evaluate the expansion of the string.
    -- in the simple case, it's merely the string in a table
    -- if the entry in ret is a string, it's copied.  If it's a table
    -- then that table's [1] is a string which is a tag name to expand.
+   if cached_expansions[str] then
+      return cached_expansions[str]
+   end
+
    local ret = {}
    local acc = ""
    local c
@@ -386,6 +392,8 @@ local function prep_expansion(str)
       ret[#ret+1] = acc
    end
 
+   cached_expansions[str] = ret
+
    return ret
 end