BIN: gitano-update-hook: Defer generation of trees and treedeltas

1 files changed, 104 insertions, 76 deletions

diff --git a/bin/gitano-update-hook b/bin/gitano-update-hook
index 7a5a66f..42588c5 100644
--- a/bin/gitano-update-hook
+++ b/bin/gitano-update-hook
@@ -102,98 +102,126 @@ end
 
 -- Populate the trees
 
-local oldtree, newtree
+local function do_expensive_populate_context(context)
 
-if oldsha == nullsha then
-   oldtree = repo.git:get(gitano.git.tree.empty_sha).content
-else
-   local thing = repo.git:get(oldsha)
-   if thing.type == "tag" then
-      thing = thing.content.object
-   end
-   if thing.type == "commit" then
-      oldtree = thing.content.tree.content
-   else
+   local oldtree, newtree
+
+   if oldsha == nullsha then
       oldtree = repo.git:get(gitano.git.tree.empty_sha).content
-      gitano.log.warn("Odd, old object", oldsha, "is not a commit or tag")
+   else
+      local thing = repo.git:get(oldsha)
+      if thing.type == "tag" then
+	 thing = thing.content.object
+      end
+      if thing.type == "commit" then
+	 oldtree = thing.content.tree.content
+      else
+	 oldtree = repo.git:get(gitano.git.tree.empty_sha).content
+	 gitano.log.warn("Odd, old object", oldsha, "is not a commit or tag")
+      end
    end
-end
 
-if newsha == nullsha then
-   newtree = repo.git:get(gitano.git.tree.empty_sha).content
-else
-   local thing = repo.git:get(newsha)
-   if thing.type == "tag" then
-      thing = thing.content.object
-   end
-   if thing.type == "commit" then
-      newtree = thing.content.tree.content
-   else
+   if newsha == nullsha then
       newtree = repo.git:get(gitano.git.tree.empty_sha).content
-      gitano.log.warn("Odd, new object", oldsha, "is not a commit or tag")
+   else
+      local thing = repo.git:get(newsha)
+      if thing.type == "tag" then
+	 thing = thing.content.object
+      end
+      if thing.type == "commit" then
+	 newtree = thing.content.tree.content
+      else
+	 newtree = repo.git:get(gitano.git.tree.empty_sha).content
+	 gitano.log.warn("Odd, new object", oldsha, "is not a commit or tag")
+      end
    end
-end
 
--- First, populate gitano/starttree and gitano/targettree
+   -- First, populate gitano/starttree and gitano/targettree
 
-local function set_list(tag, entries)
-   -- Make the set for direct string tests
-   for i = 1, #entries do
-      entries[entries[i]] = true
+   local function set_list(tag, entries)
+      -- Make the set for direct string tests
+      for i = 1, #entries do
+	 entries[entries[i]] = true
+      end
+      context[tag] = entries
    end
-   context[tag] = entries
-end
 
-local function populate_tree(tag, tree)
-   local flat_tree = gitano.git.tree.flatten(tree)
-   local names = {}
-   for fn in pairs(flat_tree) do
-      names[#names+1] = fn
+   local function populate_tree(tag, tree)
+      local flat_tree = gitano.git.tree.flatten(tree)
+      local names = {}
+      for fn in pairs(flat_tree) do
+	 names[#names+1] = fn
+      end
+      set_list(tag, names)
    end
-   set_list(tag, names)
-end
-
-populate_tree("start_tree", oldtree)
-populate_tree("target_tree", newtree)
 
--- Now gitano/treedelta
-local delta = oldtree:diff_to(newtree)
-local targets, added, deleted, modified, renamed, renamedto =
-   {}, {}, {}, {}, {}, {}
-
-for i = 1, #delta do
-   local details = delta[i]
-   local fname = details.filename
-   targets[#targets+1] = fname
-   if details.action == "A" then
-      added[#added+1] = fname
-   end
-   if details.action == "C" and details.score == "100" then
-      added[#added+1] = fname
-   end
-   if details.action == "D" then
-      deleted[#deleted+1] = fname
-   end
-   if details.action == "M" or
-      ((details.action == "R" or details.action == "C") and
-       (tonumber(details.score) < 100)) then
-      modified[#modified+1] = fname
-   end
-   if details.action == "R" then
-      renamed[#renamed+1] = details.src_name
-      renamedto[#renamedto+1] = fname
+   populate_tree("start_tree", oldtree)
+   populate_tree("target_tree", newtree)
+
+   -- Now gitano/treedelta
+   local delta = oldtree:diff_to(newtree)
+   local targets, added, deleted, modified, renamed, renamedto =
+      {}, {}, {}, {}, {}, {}
+
+   for i = 1, #delta do
+      local details = delta[i]
+      local fname = details.filename
+      targets[#targets+1] = fname
+      if details.action == "A" then
+	 added[#added+1] = fname
+      end
+      if details.action == "C" and details.score == "100" then
+	 added[#added+1] = fname
+      end
+      if details.action == "D" then
+	 deleted[#deleted+1] = fname
+      end
+      if details.action == "M" or
+	 ((details.action == "R" or details.action == "C") and
+	  (tonumber(details.score) < 100)) then
+	 modified[#modified+1] = fname
+      end
+      if details.action == "R" then
+	 renamed[#renamed+1] = details.src_name
+	 renamedto[#renamedto+1] = fname
+      end
+
+      context["treediff/kind/" .. fname] = details.endkind
+      context["treediff/oldkind/" .. fname] = details.startkind
    end
 
-   context["treediff/kind/" .. fname] = details.endkind
-   context["treediff/oldkind/" .. fname] = details.startkind
+   set_list("treediff/targets", targets)
+   set_list("treediff/added", added)
+   set_list("treediff/deleted", deleted)
+   set_list("treediff/modified", modified)
+   set_list("treediff/renamed", renamed)
+   set_list("treediff/renamedto", renamedto)
+end
+
+local function defer_generation(key)
+   context[key] = function(ctx)
+		     -- This populates quite a bit, so we do this
+		     -- test in case someone else got hold of this
+		     -- beforehand and manages to cross the streams
+		     if type(ctx[key]) == "function" then
+			gitano.log.chat("Treedeltas generating because of:",
+					key, " Please hold.")
+			do_expensive_populate_context(ctx)
+			gitano.log.chat("Treedeltas built, continuing")
+		     end
+		     -- And return what we were meant to be
+		     return ctx[key]
+		  end
 end
 
-set_list("treediff/targets", targets)
-set_list("treediff/added", added)
-set_list("treediff/deleted", deleted)
-set_list("treediff/modified", modified)
-set_list("treediff/renamed", renamed)
-set_list("treediff/renamedto", renamedto)
+defer_generation "start_tree"
+defer_generation "target_tree"
+defer_generation "treediff/targets"
+defer_generation "treediff/added"
+defer_generation "treediff/deleted"
+defer_generation "treediff/modified"
+defer_generation "treediff/renamed"
+defer_generation "treediff/renamedto"
 
 -- Run the ruleset given the contextet