AU: Try delta updates first, then full updates

src/platform/update_engine/install_action.cc

 // Copyright (c) 2009 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "update_engine/install_action.h"
 #include <errno.h>
+#include <string>
 #include <vector>
 #include <gflags/gflags.h>
 #include "update_engine/filesystem_iterator.h"
 #include "update_engine/gzip.h"
 #include "update_engine/subprocess.h"
 #include "update_engine/utils.h"
 
 DEFINE_string(mount_install_path, "",
               "If set, the path to use when mounting the "
               "destination device during install");
 
+using std::string;
 using std::vector;
 
 namespace chromeos_update_engine {
 
 namespace {
 const string kBspatchPath = "/usr/bin/bspatch";
 }
 
 void InstallAction::PerformAction() {
   ScopedActionCompleter completer(processor_, this);
@@ skipping 89 matching lines @@
              S_ISSOCK(file.mode())) {
     InstallFileSpecialFile(mountpoint, file, path, parser, exists);
   } else if (S_ISREG(file.mode())) {
     InstallFileRegularFile(mountpoint, file, path, parser, exists);
   } else {
     // unknown mode type
     TEST_AND_RETURN_FALSE(false);
   }
 
   // chmod/chown new file
+  TEST_AND_RETURN_FALSE(file.has_uid() && file.has_gid());
+  TEST_AND_RETURN_FALSE_ERRNO(lchown((mountpoint + path).c_str(),
+                                     file.uid(), file.gid()) == 0);
   if (!S_ISLNK(file.mode()))
     TEST_AND_RETURN_FALSE_ERRNO(chmod((mountpoint + path).c_str(), file.mode())
                                 == 0);
-  TEST_AND_RETURN_FALSE(file.has_uid() && file.has_gid());
-  TEST_AND_RETURN_FALSE_ERRNO(lchown((mountpoint + path).c_str(),
-                                     file.uid(), file.gid()) == 0);
   return true;
 }
 
 bool InstallAction::InstallFileRegularFile(
     const std::string& mountpoint,
     const DeltaArchiveManifest_File& file,
     const std::string& path,
     const DeltaDiffParser& parser,
     const bool exists) const {
   if (!file.has_data_format())
@@ skipping 106 matching lines @@
     symlink_data = decompressed_symlink_data;
   }
   symlink_data.push_back('\0');
   TEST_AND_RETURN_FALSE_ERRNO(symlink(&symlink_data[0],
                                       (mountpoint + path).c_str()) == 0);
   return true;
 }
 
 
 }  //   namespace chromeos_update_engine