Copy flatbuffers efficiently and respecting DAGs.
Deduce the memory region needed to be copied by traversing the DAG, and
then copy it. This has no mallocs (yay!), and works with DAGs.
There are some cases where we actually want to copy things recursively.
Do that when asked.
Change-Id: Ia0ffde26d569fa92ee2bbb49706c17d9d657d125
diff --git a/aos/flatbuffers.h b/aos/flatbuffers.h
index b619452..21dd30c 100644
--- a/aos/flatbuffers.h
+++ b/aos/flatbuffers.h
@@ -128,6 +128,38 @@
// Wipes out the data buffer. This is handy to mark an instance as freed, and
// make attempts to use it fail more obviously.
void Wipe() { memset(data(), 0, size()); }
+
+ virtual bool Verify() const {
+ flatbuffers::Verifier v(data(), size());
+ return v.VerifyTable(&message());
+ }
+};
+
+// Non-owning Span backed flatbuffer.
+template <typename T>
+class FlatbufferSpan : public Flatbuffer<T> {
+ public:
+ // Builds a flatbuffer pointing to the contents of a span.
+ FlatbufferSpan(const absl::Span<const uint8_t> data) : data_(data) {}
+ // Builds a Flatbuffer pointing to the contents of another flatbuffer.
+ FlatbufferSpan(const Flatbuffer<T> &other) { data_ = other.span(); }
+
+ // Copies the data from the other flatbuffer.
+ FlatbufferSpan &operator=(const Flatbuffer<T> &other) {
+ data_ = other.span();
+ return *this;
+ }
+
+ virtual ~FlatbufferSpan() override {}
+
+ const uint8_t *data() const override {
+ return data_.data();
+ }
+ uint8_t *data() override { return CHECK_NOTNULL(nullptr); }
+ size_t size() const override { return data_.size(); }
+
+ private:
+ absl::Span<const uint8_t> data_;
};
// String backed flatbuffer.
@@ -360,6 +392,13 @@
return absl::Span<const uint8_t>(buffer_.data(), buffer_.size());
}
+ bool Verify() const override {
+ // TODO(austin): Should we push full_span up to Flatbuffer<> class?
+ // The base pointer has the wrong alignment if we strip off the size.
+ flatbuffers::Verifier v(full_span().data(), full_span().size());
+ return v.VerifyTable(&this->message());
+ }
+
private:
flatbuffers::DetachedBuffer buffer_;
};