[yocto] [PATCH 2/2][Image Creator] Hob Cache for speed up switching

[Ke Liping]

From: Liping Ke <liping.ke at intel.com>

This patch is to cache target dependency tree for Hob (cache impl).
Hob User might switch between different configuration combinations
(machine, sdk-machine, distro, etc). Each dependency re-calcuation
might be time consuming. We use a hashset to cache those result for
avoiding recalc. Thus we can speed up UI data loading speed in
some cases.

Signed-off-by: Liping Ke <liping.ke at intel.com>
---
 bitbake/lib/bb/ui/crumbs/hobeventhandler.py |   13 +++++++++++++
 bitbake/lib/bb/ui/crumbs/tasklistmodel.py   |    5 +++++
 bitbake/lib/bb/ui/hob.py                    |   18 +++++++++++++++++-
 3 files changed, 35 insertions(+), 1 deletions(-)

diff --git a/bitbake/lib/bb/ui/crumbs/hobeventhandler.py b/bitbake/lib/bb/ui/crumbs/hobeventhandler.py
index 8c8d9e2..c6d3bd5 100644
--- a/bitbake/lib/bb/ui/crumbs/hobeventhandler.py
+++ b/bitbake/lib/bb/ui/crumbs/hobeventhandler.py
@@ -110,6 +110,19 @@ class HobHandler(gobject.GObject):
             self.emit("data-generated")
             self.generating = False
             if event._model:
+                # Currently, use these three property as the key, in the future
+                # more elements might be needed
+                mach = hobprefs.curr_mach
+                if mach == None:
+                    mach = ""
+                sdk_mach = hobprefs.curr_sdk_mach
+                if sdk_mach == None:
+                    sdk_mach = ""
+                distro = hobprefs.curr_distro
+                if distro == None:
+                    distro = ""
+                hash_key = mach + "," + sdk_mach + "," + distro
+                self.model.targetTreeCache[hash_key] = event._model 
                 self.model.populate(event._model)
         elif isinstance(event, bb.event.ConfigFilesFound):
             var = event._variable
diff --git a/bitbake/lib/bb/ui/crumbs/tasklistmodel.py b/bitbake/lib/bb/ui/crumbs/tasklistmodel.py
index 5e979b7..bcd6328 100644
--- a/bitbake/lib/bb/ui/crumbs/tasklistmodel.py
+++ b/bitbake/lib/bb/ui/crumbs/tasklistmodel.py
@@ -102,6 +102,11 @@ class TaskListModel(gtk.ListStore):
         self.packages = None
         self.images = None
         self.selected_image = None
+        # This var is used for caching target package dependency data. This
+        # data will be impacted by layers, distros, machine, sdk_machine value
+        # which is now all saved in HobPrefs data. For the hashset cache, it's
+        # obvious that the key will be those properties combination.
+        self.targetTreeCache = {}
         
         gtk.ListStore.__init__ (self,
                                 gobject.TYPE_STRING,
diff --git a/bitbake/lib/bb/ui/hob.py b/bitbake/lib/bb/ui/hob.py
index 76cb294..5f6fdf5 100644
--- a/bitbake/lib/bb/ui/hob.py
+++ b/bitbake/lib/bb/ui/hob.py
@@ -166,7 +166,23 @@ class MainWindow (gtk.Window):
             self.configurator.setLocalConfVar('MACHINE', mach)
             self.configurator.writeLocalConf()
             handler.set_machine(mach)
-            handler.reload_data()
+            mach = self.prefs.curr_mach
+            if mach == None:
+                mach = ""
+            sdk_mach = self.prefs.curr_sdk_mach
+            if sdk_mach == None:
+                sdk_mach = ""
+            distro = self.prefs.curr_distro
+            if distro == None:
+                distro = ""
+            hash_key = mach + "," + sdk_mach + "," + distro
+            # Only when this target tree has not been cached, need we reload
+            # the target tree data
+            if (self.model.targetTreeCache.has_key(hash_key) == False):
+                handler.reload_data()
+            # Otherwise, simply reload the cache data
+            else:
+                handler.model.populate(self.model.targetTreeCache[hash_key])
 
     def update_machines(self, handler, machines):
         active = 0
-- 
1.7.0.4