[res] Zero big buffer memory on backing up
When a memory chunk gets returned into BigBuffer, it may have
some data written already. BigBuffer is supposed to give out
zeroed memory, so BackUp() needs to zero it as well
Bug: 336758568
Bug: 342579978
Test: unit test + bundletool on the attached aab
Flag: EXEMPT bugfix
Change-Id: I8ecd60e84dbe16570a92d82370d1633af72599c8
diff --git a/libs/androidfw/BigBuffer.cpp b/libs/androidfw/BigBuffer.cpp
index bedfc49..43b56c3 100644
--- a/libs/androidfw/BigBuffer.cpp
+++ b/libs/androidfw/BigBuffer.cpp
@@ -17,8 +17,8 @@
#include <androidfw/BigBuffer.h>
#include <algorithm>
+#include <iterator>
#include <memory>
-#include <vector>
#include "android-base/logging.h"
@@ -78,10 +78,27 @@
std::string BigBuffer::to_string() const {
std::string result;
+ result.reserve(size_);
for (const Block& block : blocks_) {
result.append(block.buffer.get(), block.buffer.get() + block.size);
}
return result;
}
+void BigBuffer::AppendBuffer(BigBuffer&& buffer) {
+ std::move(buffer.blocks_.begin(), buffer.blocks_.end(), std::back_inserter(blocks_));
+ size_ += buffer.size_;
+ buffer.blocks_.clear();
+ buffer.size_ = 0;
+}
+
+void BigBuffer::BackUp(size_t count) {
+ Block& block = blocks_.back();
+ block.size -= count;
+ size_ -= count;
+ // BigBuffer is supposed to always give zeroed memory, but backing up usually means
+ // something has been already written into the block. Erase it.
+ std::fill_n(block.buffer.get() + block.size, count, 0);
+}
+
} // namespace android