AU: Beginnings of delta support

src/platform/update_engine/download_action.cc

Index: src/platform/update_engine/download_action.cc
diff --git a/src/platform/update_engine/download_action.cc b/src/platform/update_engine/download_action.cc
index 3a039d1af07aaa5170cd907420d36843c4452ea0..833f806edd1baa32105248768c1a9ad6ed4639ba 100644
--- a/src/platform/update_engine/download_action.cc
+++ b/src/platform/update_engine/download_action.cc
@@ -2,23 +2,19 @@
 // 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 <glib.h>
-
 #include "update_engine/action_pipe.h"
-#include "update_engine/download_action.h"
+
+using std::min;
 
 namespace chromeos_update_engine {
 
-DownloadAction::DownloadAction(const std::string& url,
-                               const std::string& output_path,
-                               off_t size, const std::string& hash,
-                               const bool should_decompress,
-                               HttpFetcher* http_fetcher)
-    : size_(size),
-      url_(url),
-      output_path_(output_path),
-      hash_(hash),
-      should_decompress_(should_decompress),
+DownloadAction::DownloadAction(HttpFetcher* http_fetcher)
+    : size_(0),
+      should_decompress_(false),
       writer_(NULL),
       http_fetcher_(http_fetcher) {}
 
@@ -29,14 +25,24 @@ void DownloadAction::PerformAction() {
   CHECK(!writer_);
   direct_file_writer_.reset(new DirectFileWriter);
 
+  // Get the InstallPlan and read it
+  CHECK(HasInputObject());
+  InstallPlan install_plan(GetInputObject());
+
+  should_decompress_ = install_plan.is_full_update;
+  url_ = install_plan.download_url;
+  output_path_ = install_plan.download_path;
+  hash_ = install_plan.download_hash;
+  install_plan.Dump();
+
   if (should_decompress_) {
     decompressing_file_writer_.reset(
         new GzipDecompressingFileWriter(direct_file_writer_.get()));
     writer_ = decompressing_file_writer_.get();
+    output_path_ = install_plan.install_path;
   } else {
     writer_ = direct_file_writer_.get();
   }
-
   int rc = writer_->Open(output_path_.c_str(),
                          O_TRUNC | O_WRONLY | O_CREAT | O_LARGEFILE, 0644);
   if (rc < 0) {
@@ -58,35 +64,29 @@ void DownloadAction::TerminateProcessing() {
 void DownloadAction::ReceivedBytes(HttpFetcher *fetcher,
                                    const char* bytes,
                                    int length) {
-  int bytes_written = 0;
-  do {
-    CHECK_GT(length, bytes_written);
-    int rc = writer_->Write(bytes + bytes_written, length - bytes_written);
-    // TODO(adlr): handle write error
-    CHECK_GE(rc, 0);
-    bytes_written += rc;
-  } while (length != bytes_written);
+  int rc = writer_->Write(bytes, length);
+  TEST_AND_RETURN(rc >= 0);
   omaha_hash_calculator_.Update(bytes, length);
 }
 
 void DownloadAction::TransferComplete(HttpFetcher *fetcher, bool successful) {
   if (writer_) {
-    CHECK_EQ(0, writer_->Close()) << errno;
+    CHECK_EQ(writer_->Close(), 0) << errno;
     writer_ = NULL;
   }
   if (successful) {
     // Make sure hash is correct
     omaha_hash_calculator_.Finalize();
     if (omaha_hash_calculator_.hash() != hash_) {
-      LOG(INFO) << "Download of " << url_ << " failed. Expect hash "
-                << hash_ << " but got hash " << omaha_hash_calculator_.hash();
+      LOG(ERROR) << "Download of " << url_ << " failed. Expect hash "
+                 << hash_ << " but got hash " << omaha_hash_calculator_.hash();
       successful = false;
     }
   }
 
   // Write the path to the output pipe if we're successful
   if (successful && HasOutputPipe())
-    SetOutputObject(output_path_);
+    SetOutputObject(GetInputObject());
   processor_->ActionComplete(this, successful);
 }