Add and emit download action error codes.

download_action.cc

 // Copyright (c) 2010 The Chromium OS 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/download_action.h"
 #include <errno.h>
 #include <algorithm>
 #include <string>
 #include <vector>
 #include <glib.h>
@@ skipping 43 matching lines @@
       delta_performer_.reset(new DeltaPerformer);
       writer_ = delta_performer_.get();
     }
   }
   int rc = writer_->Open(install_plan_.install_path.c_str(),
                          O_TRUNC | O_WRONLY | O_CREAT | O_LARGEFILE,
                          0644);
   if (rc < 0) {
     LOG(ERROR) << "Unable to open output file " << install_plan_.install_path;
     // report error to processor
-    processor_->ActionComplete(this, kActionCodeError);
+    processor_->ActionComplete(this, kActionCodeInstallDeviceOpenError);
     return;
   }
   if (!install_plan_.is_full_update) {
     if (!delta_performer_->OpenKernel(
             install_plan_.kernel_install_path.c_str())) {
       LOG(ERROR) << "Unable to open kernel file "
                  << install_plan_.kernel_install_path.c_str();
       writer_->Close();
-      processor_->ActionComplete(this, kActionCodeError);
+      processor_->ActionComplete(this, kActionCodeKernelDeviceOpenError);
       return;
     }
   }
   http_fetcher_->BeginTransfer(install_plan_.download_url);
 }
 
 void DownloadAction::TerminateProcessing() {
   CHECK(writer_);
   CHECK_EQ(writer_->Close(), 0);
   writer_ = NULL;
@@ skipping 25 matching lines @@
 
   LOG(INFO) << "FlushLinuxCaches done.";
 }
 }
 
 void DownloadAction::TransferComplete(HttpFetcher *fetcher, bool successful) {
   if (writer_) {
     CHECK_EQ(writer_->Close(), 0) << errno;
     writer_ = NULL;
   }
-  if (successful) {
+  ActionExitCode code =
+      successful ? kActionCodeSuccess : kActionCodeDownloadTransferError;
+  if (code == kActionCodeSuccess) {
     // Make sure hash is correct
     omaha_hash_calculator_.Finalize();
     if (omaha_hash_calculator_.hash() != install_plan_.download_hash) {
       LOG(ERROR) << "Download of " << install_plan_.download_url
                  << " failed. Expect hash " << install_plan_.download_hash
                  << " but got hash " << omaha_hash_calculator_.hash();
-      successful = false;
+      code = kActionCodeDownloadHashMismatchError;
     }
   }
 
   FlushLinuxCaches();
 
-  // Write the path to the output pipe if we're successful
-  if (successful && HasOutputPipe())
+  // Write the path to the output pipe if we're successful.
+  if (code == kActionCodeSuccess && HasOutputPipe())
     SetOutputObject(GetInputObject());
-  processor_->ActionComplete(
-      this,
-      successful ? kActionCodeSuccess : kActionCodeError);
+  processor_->ActionComplete(this, code);
 }
 
 };  // namespace {}