update the vector_view, test=develop (#3869)

lite/model_parser/flatbuffers/vector_view.h

@@ -18,6 +18,7 @@
 #include <type_traits>
 #include <vector>
 #include "flatbuffers/flatbuffers.h"
+#include "lite/utils/cp_logging.h"
 
 namespace paddle {
 namespace lite {
@@ -32,7 +33,7 @@ struct ElementTraits {
 };
 
 template <typename T>
-struct ElementTraits<T,
+struct ElementTraits<T*,
                      typename std::enable_if<std::is_class<T>::value>::type> {
   typedef flatbuffers::Offset<T> element_type;
 };
@@ -76,6 +77,15 @@ class VectorView {
   typename Traits::const_iterator begin() const { return cvec_->begin(); }
   typename Traits::const_iterator end() const { return cvec_->end(); }
   size_t size() const { return cvec_->size(); }
+  operator std::vector<T>() {
+    VLOG(10) << "Copying elements out of VectorView will damage performance.";
+    std::vector<T> tmp;
+    tmp.reserve(cvec_->size());
+    for (auto val : *cvec_) {
+      tmp.push_back(val);
+    }
+    return tmp;
+  }
   ~VectorView() = default;
 
  private:
@@ -90,22 +100,22 @@ struct FBSStrIterator {
       VI;
 
   explicit FBSStrIterator(const VI& iter) { iter_ = iter; }
-  const VI& RawIter() const { return iter_; }
+  const VI& raw_iter() const { return iter_; }
 
   bool operator==(const FBSStrIterator& other) const {
-    return iter_ == other.RawIter();
+    return iter_ == other.raw_iter();
   }
 
   bool operator<(const FBSStrIterator& other) const {
-    return iter_ < other.RawIter();
+    return iter_ < other.raw_iter();
   }
 
   bool operator!=(const FBSStrIterator& other) const {
-    return iter_ != other.RawIter();
+    return iter_ != other.raw_iter();
   }
 
   ptrdiff_t operator-(const FBSStrIterator& other) const {
-    return iter_ - other.RawIter();
+    return iter_ - other.raw_iter();
   }
 
   std::string operator*() const { return iter_.operator*()->str(); }
@@ -144,6 +154,15 @@ class VectorView<std::string, Flatbuffers> {
   FBSStrIterator begin() const { return FBSStrIterator(cvec_->begin()); }
   FBSStrIterator end() const { return FBSStrIterator(cvec_->end()); }
   size_t size() const { return cvec_->size(); }
+  operator std::vector<std::string>() {
+    VLOG(10) << "Copying elements out of VectorView will damage performance.";
+    std::vector<std::string> tmp;
+    tmp.reserve(cvec_->size());
+    for (auto val : *cvec_) {
+      tmp.push_back(val->str());
+    }
+    return tmp;
+  }
   ~VectorView() = default;
 
  private:

lite/model_parser/flatbuffers/vector_view_test.cc

@@ -85,15 +85,15 @@ TEST(VectorView, Flatbuffers) {
   auto program = fbs::proto::GetProgramDesc(fbb.GetBufferPointer());
 
   // BlockDesc View
-  VectorView<proto::BlockDesc> block_view(program->blocks());
+  VectorView<proto::BlockDesc*> block_view(program->blocks());
   EXPECT_EQ(block_view.size(), static_cast<size_t>(2));
   EXPECT_EQ(block_view[0]->idx(), 0);
   EXPECT_EQ(block_view[1]->idx(), 1);
 
   // OpDesc & Attr View
-  VectorView<proto::OpDesc> op_view(block_view[0]->ops());
+  VectorView<proto::OpDesc*> op_view(block_view[0]->ops());
   EXPECT_EQ(op_view[0]->type()->str(), std::string("hello!"));
-  VectorView<proto::OpDesc_::Attr> attr_view(op_view[0]->attrs());
+  VectorView<proto::OpDesc_::Attr*> attr_view(op_view[0]->attrs());
 
   // int32_t View
   VectorView<int32_t> ints_view(attr_view[0]->ints());
@@ -106,6 +106,10 @@ TEST(VectorView, Flatbuffers) {
   for (size_t i = 0; i < ints_view.size(); ++i) {
     EXPECT_EQ(ints_view[i], ints[i]);
   }
+  std::vector<int32_t> ints_2(ints_view);
+  for (size_t i = 0; i < ints_2.size(); ++i) {
+    EXPECT_EQ(ints_2[i], ints[i]);
+  }
 
   // String View
   VectorView<std::string> strings_view(attr_view[0]->strings());
@@ -119,6 +123,10 @@ TEST(VectorView, Flatbuffers) {
   for (size_t i = 0; i < strings_view.size(); ++i) {
     EXPECT_EQ(strings_view[i], strings[i]);
   }
+  std::vector<std::string> string_2(strings_view);
+  for (size_t i = 0; i < string_2.size(); ++i) {
+    EXPECT_EQ(string_2[i], strings[i]);
+  }
 }
 
 }  // namespace lite