Transfer memory ownership when stacking ExtentWriters.
The ExtentWriter implementations are meant to be stacked in a way that
the underlying extent writer can't be reused. Calling End() on the top
of the stack will call End() on every ExtentWriter.
This patch enforces this design decision in the interface transfering
the ownership of the ExtentWriter when stacking them using a unique_ptr
instead of a plain pointer.
Bug: 23604708
Test: Updated unittests.
Change-Id: Ie3b5b9cbb3058359c487a783f6fb3c0ac65bde00
diff --git a/delta_performer.cc b/delta_performer.cc
index 194f934..2d4517f 100644
--- a/delta_performer.cc
+++ b/delta_performer.cc
@@ -30,6 +30,7 @@
#include <base/strings/string_util.h>
#include <base/strings/stringprintf.h>
#include <chromeos/data_encoding.h>
+#include <chromeos/make_unique_ptr.h>
#include <google/protobuf/repeated_field.h>
#include "update_engine/bzip_extent_writer.h"
@@ -50,7 +51,6 @@
using google::protobuf::RepeatedPtrField;
using std::min;
using std::string;
-using std::unique_ptr;
using std::vector;
namespace chromeos_update_engine {
@@ -660,21 +660,13 @@
// Extract the signature message if it's in this operation.
ExtractSignatureMessage(operation);
- DirectExtentWriter direct_writer;
- ZeroPadExtentWriter zero_pad_writer(&direct_writer);
- unique_ptr<BzipExtentWriter> bzip_writer;
+ // Setup the ExtentWriter stack based on the operation type.
+ std::unique_ptr<ExtentWriter> writer =
+ chromeos::make_unique_ptr(new ZeroPadExtentWriter(
+ chromeos::make_unique_ptr(new DirectExtentWriter())));
- // Since bzip decompression is optional, we have a variable writer that will
- // point to one of the ExtentWriter objects above.
- ExtentWriter* writer = nullptr;
- if (operation.type() == InstallOperation::REPLACE) {
- writer = &zero_pad_writer;
- } else if (operation.type() == InstallOperation::REPLACE_BZ) {
- bzip_writer.reset(new BzipExtentWriter(&zero_pad_writer));
- writer = bzip_writer.get();
- } else {
- NOTREACHED();
- }
+ if (operation.type() == InstallOperation::REPLACE_BZ)
+ writer.reset(new BzipExtentWriter(std::move(writer)));
// Create a vector of extents to pass to the ExtentWriter.
vector<Extent> extents;