[OE-core] [PATCH 3/5] rootfs.py: support ipk incremental image generation

[Hongxu Jia]

The incremental image generation is based on the previous existing
image, adds new packages, upgrades existing packages, and removes unused
packages.

[YOCTO #1894]
Signed-off-by: Hongxu Jia <hongxu.jia at windriver.com>
---
 meta/lib/oe/rootfs.py | 52 ++++++++++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 49 insertions(+), 3 deletions(-)

diff --git a/meta/lib/oe/rootfs.py b/meta/lib/oe/rootfs.py
index 3bcb812..93106c2 100644
--- a/meta/lib/oe/rootfs.py
+++ b/meta/lib/oe/rootfs.py
@@ -438,13 +438,25 @@ class OpkgRootfs(Rootfs):
     def __init__(self, d, manifest_dir):
         super(OpkgRootfs, self).__init__(d)
 
-        bb.utils.remove(self.image_rootfs, True)
-        bb.utils.remove(self.d.getVar('MULTILIB_TEMP_ROOTFS', True), True)
         self.manifest = OpkgManifest(d, manifest_dir)
         self.opkg_conf = self.d.getVar("IPKGCONF_TARGET", True)
         self.pkg_archs = self.d.getVar("ALL_MULTILIB_PACKAGE_ARCHS", True)
 
-        self.pm = OpkgPM(d, self.image_rootfs, self.opkg_conf, self.pkg_archs)
+        self.inc_opkg_image_gen = self.d.getVar('INC_IPK_IMAGE_GEN', True) or ""
+        if self.inc_opkg_image_gen != '1':
+            bb.utils.remove(self.image_rootfs, True)
+            self.pm = OpkgPM(d,
+                             self.image_rootfs,
+                             self.opkg_conf,
+                             self.pkg_archs)
+        else:
+            self.pm = OpkgPM(d,
+                             self.image_rootfs,
+                             self.opkg_conf,
+                             self.pkg_archs)
+            self.pm.recover_packaging_data()
+
+        bb.utils.remove(self.d.getVar('MULTILIB_TEMP_ROOTFS', True), True)
 
     """
     This function was reused from the old implementation.
@@ -508,6 +520,34 @@ class OpkgRootfs(Rootfs):
 
         self._multilib_sanity_test(dirs)
 
+    '''
+    While ipk incremental image generation is enabled, it will remove the
+    unneeded pkgs by comparing the old full manifest in previous existing
+    image and the new full manifest in the current image.
+    '''
+    def _create_incremental(self, pkgs_initial_install):
+        if self.inc_opkg_image_gen == "1":
+            # Parse full manifest in previous existing image creation session
+            old_full_manifest = self.manifest.parse_full_manifest()
+
+            # Create full manifest for the current image session, the old one
+            # will be replaced by the new one.
+            self.manifest.create_full()
+
+            # Parse full manifest in current image creation session
+            new_full_manifest = self.manifest.parse_full_manifest()
+
+            pkg_to_remove = list()
+            for pkg in old_full_manifest:
+                if pkg not in new_full_manifest:
+                    pkg_to_remove.append(pkg)
+
+            self.pm.update()
+
+            if pkg_to_remove != []:
+                bb.note('decremental removed: %s' % ' '.join(pkg_to_remove))
+                self.pm.remove(pkg_to_remove)
+
     def _create(self):
         pkgs_to_install = self.manifest.parse_initial_manifest()
         opkg_pre_process_cmds = self.d.getVar('OPKG_PREPROCESS_COMMANDS', True)
@@ -518,6 +558,9 @@ class OpkgRootfs(Rootfs):
         if (self.d.getVar('BUILD_IMAGES_FROM_FEEDS', True) or "") != "1":
             self.pm.write_index()
 
+        if self.inc_opkg_image_gen == "1":
+            self._create_incremental(pkgs_to_install)
+
         execute_pre_post_process(self.d, opkg_pre_process_cmds)
 
         self.pm.update()
@@ -540,6 +583,9 @@ class OpkgRootfs(Rootfs):
         execute_pre_post_process(self.d, opkg_post_process_cmds)
         execute_pre_post_process(self.d, rootfs_post_install_cmds)
 
+        if self.inc_opkg_image_gen == "1":
+            self.pm.backup_packaging_data()
+
     def _get_delayed_postinsts(self):
         pkg_list = []
         status_file = os.path.join(self.image_rootfs,
-- 
1.8.1.2