Add idiomatic C++ API for grpc::Slice construction that doesn't

require using grpc_slice

Author: vjpai

include/grpc++/support/slice.h

@@ -44,6 +44,20 @@ class Slice final {
   /// Construct a slice from \a slice, stealing a reference.
   Slice(grpc_slice slice, StealRef);
 
+  /// Allocate a slice of specified size
+  Slice(size_t len);
+
+  /// Construct a slice from a copied buffer
+  Slice(const void* buf, size_t len);
+
+  /// Construct a slice from a copied string
+  Slice(const grpc::string& str);
+
+  enum StaticSlice { STATIC_SLICE };
+
+  /// Construct a slice from a static buffer
+  Slice(const void* buf, size_t len, StaticSlice);
+
   /// Copy constructor, adds a reference.
   Slice(const Slice& other);
 

src/cpp/util/slice_cc.cc

@@ -28,6 +28,19 @@ Slice::Slice(grpc_slice slice, AddRef) : slice_(grpc_slice_ref(slice)) {}
 
 Slice::Slice(grpc_slice slice, StealRef) : slice_(slice) {}
 
+Slice::Slice(size_t len) : slice_(grpc_slice_malloc(len)) {}
+
+Slice::Slice(const void* buf, size_t len)
+    : slice_(grpc_slice_from_copied_buffer(reinterpret_cast<const char*>(buf),
+                                           len)) {}
+
+Slice::Slice(const grpc::string& str)
+    : slice_(grpc_slice_from_copied_buffer(str.c_str(), str.length())) {}
+
+Slice::Slice(const void* buf, size_t len, StaticSlice)
+    : slice_(grpc_slice_from_static_buffer(reinterpret_cast<const char*>(buf),
+                                           len)) {}
+
 Slice::Slice(const Slice& other) : slice_(grpc_slice_ref(other.slice_)) {}
 
 }  // namespace grpc

test/cpp/qps/client.h

@@ -88,9 +88,7 @@ class ClientRequestCreator<ByteBuffer> {
     if (payload_config.has_bytebuf_params()) {
       std::unique_ptr<char[]> buf(
           new char[payload_config.bytebuf_params().req_size()]);
-      grpc_slice s = grpc_slice_from_copied_buffer(
-          buf.get(), payload_config.bytebuf_params().req_size());
-      Slice slice(s, Slice::STEAL_REF);
+      Slice slice(buf.get(), payload_config.bytebuf_params().req_size());
       *req = ByteBuffer(&slice, 1);
     } else {
       GPR_ASSERT(false);  // not appropriate for this specialization

test/cpp/util/byte_buffer_proto_helper.cc

@@ -36,8 +36,7 @@ std::unique_ptr<ByteBuffer> SerializeToByteBuffer(
     grpc::protobuf::Message* message) {
   grpc::string buf;
   message->SerializeToString(&buf);
-  grpc_slice s = grpc_slice_from_copied_string(buf.c_str());
-  Slice slice(s, Slice::STEAL_REF);
+  Slice slice(buf);
   return std::unique_ptr<ByteBuffer>(new ByteBuffer(&slice, 1));
 }
 

test/cpp/util/byte_buffer_test.cc

@@ -34,33 +34,30 @@ const char* kContent2 = "yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy world";
 class ByteBufferTest : public ::testing::Test {};
 
 TEST_F(ByteBufferTest, CreateFromSingleSlice) {
-  grpc_slice hello = grpc_slice_from_copied_string(kContent1);
-  Slice s(hello, Slice::STEAL_REF);
+  Slice s(kContent1);
   ByteBuffer buffer(&s, 1);
+  EXPECT_EQ(strlen(kContent1), buffer.Length());
 }
 
 TEST_F(ByteBufferTest, CreateFromVector) {
-  grpc_slice hello = grpc_slice_from_copied_string(kContent1);
-  grpc_slice world = grpc_slice_from_copied_string(kContent2);
   std::vector<Slice> slices;
-  slices.push_back(Slice(hello, Slice::STEAL_REF));
-  slices.push_back(Slice(world, Slice::STEAL_REF));
+  slices.emplace_back(kContent1);
+  slices.emplace_back(kContent2);
   ByteBuffer buffer(&slices[0], 2);
+  EXPECT_EQ(strlen(kContent1) + strlen(kContent2), buffer.Length());
 }
 
 TEST_F(ByteBufferTest, Clear) {
-  grpc_slice hello = grpc_slice_from_copied_string(kContent1);
-  Slice s(hello, Slice::STEAL_REF);
+  Slice s(kContent1);
   ByteBuffer buffer(&s, 1);
   buffer.Clear();
+  EXPECT_EQ(static_cast<size_t>(0), buffer.Length());
 }
 
 TEST_F(ByteBufferTest, Length) {
-  grpc_slice hello = grpc_slice_from_copied_string(kContent1);
-  grpc_slice world = grpc_slice_from_copied_string(kContent2);
   std::vector<Slice> slices;
-  slices.push_back(Slice(hello, Slice::STEAL_REF));
-  slices.push_back(Slice(world, Slice::STEAL_REF));
+  slices.emplace_back(kContent1);
+  slices.emplace_back(kContent2);
   ByteBuffer buffer(&slices[0], 2);
   EXPECT_EQ(strlen(kContent1) + strlen(kContent2), buffer.Length());
 }

test/cpp/util/cli_call.cc

@@ -119,8 +119,7 @@ void CliCall::WritesDone() {
 }
 
 void CliCall::WriteAndWait(const grpc::string& request) {
-  grpc_slice s = grpc_slice_from_copied_string(request.c_str());
-  grpc::Slice req_slice(s, grpc::Slice::STEAL_REF);
+  grpc::Slice req_slice(request);
   grpc::ByteBuffer send_buffer(&req_slice, 1);
 
   gpr_mu_lock(&write_mu_);

test/cpp/util/slice_test.cc

@@ -28,13 +28,41 @@ const char* kContent = "hello xxxxxxxxxxxxxxxxxxxx world";
 
 class SliceTest : public ::testing::Test {
  protected:
+  void CheckSliceSize(const Slice& s, const grpc::string& content) {
+    EXPECT_EQ(content.size(), s.size());
+  }
   void CheckSlice(const Slice& s, const grpc::string& content) {
     EXPECT_EQ(content.size(), s.size());
     EXPECT_EQ(content,
               grpc::string(reinterpret_cast<const char*>(s.begin()), s.size()));
   }
 };
 
+TEST_F(SliceTest, Empty) {
+  Slice empty_slice;
+  CheckSlice(empty_slice, "");
+}
+
+TEST_F(SliceTest, Sized) {
+  Slice sized_slice(strlen(kContent));
+  CheckSliceSize(sized_slice, kContent);
+}
+
+TEST_F(SliceTest, String) {
+  Slice spp(kContent);
+  CheckSlice(spp, kContent);
+}
+
+TEST_F(SliceTest, Buf) {
+  Slice spp(kContent, strlen(kContent));
+  CheckSlice(spp, kContent);
+}
+
+TEST_F(SliceTest, StaticBuf) {
+  Slice spp(kContent, strlen(kContent), Slice::STATIC_SLICE);
+  CheckSlice(spp, kContent);
+}
+
 TEST_F(SliceTest, Steal) {
   grpc_slice s = grpc_slice_from_copied_string(kContent);
   Slice spp(s, Slice::STEAL_REF);
@@ -48,11 +76,6 @@ TEST_F(SliceTest, Add) {
   CheckSlice(spp, kContent);
 }
 
-TEST_F(SliceTest, Empty) {
-  Slice empty_slice;
-  CheckSlice(empty_slice, "");
-}
-
 TEST_F(SliceTest, Cslice) {
   grpc_slice s = grpc_slice_from_copied_string(kContent);
   Slice spp(s, Slice::STEAL_REF);