Update //third_party/protobuf to version 3.

third_party/protobuf/src/google/protobuf/util/internal/protostream_objectsource.cc

Index: third_party/protobuf/src/google/protobuf/util/internal/protostream_objectsource.cc
diff --git a/third_party/protobuf/src/google/protobuf/util/internal/protostream_objectsource.cc b/third_party/protobuf/src/google/protobuf/util/internal/protostream_objectsource.cc
new file mode 100644
index 0000000000000000000000000000000000000000..034d616ff18d4c50c392ed7bcb08d481d4643226
--- /dev/null
+++ b/third_party/protobuf/src/google/protobuf/util/internal/protostream_objectsource.cc
@@ -0,0 +1,1045 @@
+// Protocol Buffers - Google's data interchange format
+// Copyright 2008 Google Inc.  All rights reserved.
+// https://developers.google.com/protocol-buffers/
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <google/protobuf/util/internal/protostream_objectsource.h>
+
+#include <utility>
+
+#include <google/protobuf/stubs/casts.h>
+#include <google/protobuf/stubs/logging.h>
+#include <google/protobuf/stubs/common.h>
+#include <google/protobuf/stubs/stringprintf.h>
+#include <google/protobuf/stubs/time.h>
+#include <google/protobuf/io/coded_stream.h>
+#include <google/protobuf/io/zero_copy_stream_impl.h>
+#include <google/protobuf/descriptor.h>
+#include <google/protobuf/wire_format.h>
+#include <google/protobuf/wire_format_lite.h>
+#include <google/protobuf/util/internal/field_mask_utility.h>
+#include <google/protobuf/util/internal/constants.h>
+#include <google/protobuf/util/internal/utility.h>
+#include <google/protobuf/stubs/strutil.h>
+#include <google/protobuf/stubs/map_util.h>
+#include <google/protobuf/stubs/status_macros.h>
+
+
+namespace google {
+namespace protobuf {
+namespace util {
+using util::Status;
+using util::StatusOr;
+namespace error {
+using util::error::Code;
+using util::error::INTERNAL;
+}
+namespace converter {
+
+using google::protobuf::Descriptor;
+using google::protobuf::EnumValueDescriptor;
+using google::protobuf::FieldDescriptor;
+using google::protobuf::internal::WireFormat;
+using google::protobuf::internal::WireFormatLite;
+using util::Status;
+using util::StatusOr;
+
+namespace {
+// Finds a field with the given number. NULL if none found.
+const google::protobuf::Field* FindFieldByNumber(
+    const google::protobuf::Type& type, int number);
+
+// Returns true if the field is packable.
+bool IsPackable(const google::protobuf::Field& field);
+
+// Finds an enum value with the given number. NULL if none found.
+const google::protobuf::EnumValue* FindEnumValueByNumber(
+    const google::protobuf::Enum& tech_enum, int number);
+
+// Utility function to format nanos.
+const string FormatNanos(uint32 nanos);
+}  // namespace
+
+
+ProtoStreamObjectSource::ProtoStreamObjectSource(
+    google::protobuf::io::CodedInputStream* stream, TypeResolver* type_resolver,
+    const google::protobuf::Type& type)
+    : stream_(stream),
+      typeinfo_(TypeInfo::NewTypeInfo(type_resolver)),
+      own_typeinfo_(true),
+      type_(type) {
+  GOOGLE_LOG_IF(DFATAL, stream == NULL) << "Input stream is NULL.";
+}
+
+ProtoStreamObjectSource::ProtoStreamObjectSource(
+    google::protobuf::io::CodedInputStream* stream, const TypeInfo* typeinfo,
+    const google::protobuf::Type& type)
+    : stream_(stream), typeinfo_(typeinfo), own_typeinfo_(false), type_(type) {
+  GOOGLE_LOG_IF(DFATAL, stream == NULL) << "Input stream is NULL.";
+}
+
+ProtoStreamObjectSource::~ProtoStreamObjectSource() {
+  if (own_typeinfo_) {
+    delete typeinfo_;
+  }
+}
+
+Status ProtoStreamObjectSource::NamedWriteTo(StringPiece name,
+                                             ObjectWriter* ow) const {
+  return WriteMessage(type_, name, 0, true, ow);
+}
+
+const google::protobuf::Field* ProtoStreamObjectSource::FindAndVerifyField(
+    const google::protobuf::Type& type, uint32 tag) const {
+  // Lookup the new field in the type by tag number.
+  const google::protobuf::Field* field = FindFieldByNumber(type, tag >> 3);
+  // Verify if the field corresponds to the wire type in tag.
+  // If there is any discrepancy, mark the field as not found.
+  if (field != NULL) {
+    WireFormatLite::WireType expected_type =
+        WireFormatLite::WireTypeForFieldType(
+            static_cast<WireFormatLite::FieldType>(field->kind()));
+    WireFormatLite::WireType actual_type = WireFormatLite::GetTagWireType(tag);
+    if (actual_type != expected_type &&
+        (!IsPackable(*field) ||
+         actual_type != WireFormatLite::WIRETYPE_LENGTH_DELIMITED)) {
+      field = NULL;
+    }
+  }
+  return field;
+}
+
+Status ProtoStreamObjectSource::WriteMessage(const google::protobuf::Type& type,
+                                             StringPiece name,
+                                             const uint32 end_tag,
+                                             bool include_start_and_end,
+                                             ObjectWriter* ow) const {
+
+    const TypeRenderer* type_renderer = FindTypeRenderer(type.name());
+    if (type_renderer != NULL) {
+      return (*type_renderer)(this, type, name, ow);
+    }
+
+  const google::protobuf::Field* field = NULL;
+  string field_name;
+  // last_tag set to dummy value that is different from tag.
+  uint32 tag = stream_->ReadTag(), last_tag = tag + 1;
+
+  if (include_start_and_end) {
+    ow->StartObject(name);
+  }
+  while (tag != end_tag) {
+    if (tag != last_tag) {  // Update field only if tag is changed.
+      last_tag = tag;
+      field = FindAndVerifyField(type, tag);
+      if (field != NULL) {
+        field_name = field->json_name();
+      }
+    }
+    if (field == NULL) {
+      // If we didn't find a field, skip this unknown tag.
+      // TODO(wpoon): Check return boolean value.
+      WireFormat::SkipField(stream_, tag, NULL);
+      tag = stream_->ReadTag();
+      continue;
+    }
+
+    if (field->cardinality() ==
+        google::protobuf::Field_Cardinality_CARDINALITY_REPEATED) {
+      bool check_maps = true;
+
+      if (check_maps && IsMap(*field)) {
+        ow->StartObject(field_name);
+        ASSIGN_OR_RETURN(tag, RenderMap(field, field_name, tag, ow));
+        ow->EndObject();
+      } else {
+        ASSIGN_OR_RETURN(tag, RenderList(field, field_name, tag, ow));
+      }
+    } else {
+      // Render the field.
+      RETURN_IF_ERROR(RenderField(field, field_name, ow));
+      tag = stream_->ReadTag();
+    }
+  }
+  if (include_start_and_end) {
+    ow->EndObject();
+  }
+  return Status::OK;
+}
+
+StatusOr<uint32> ProtoStreamObjectSource::RenderList(
+    const google::protobuf::Field* field, StringPiece name, uint32 list_tag,
+    ObjectWriter* ow) const {
+  uint32 tag_to_return = 0;
+  ow->StartList(name);
+  if (IsPackable(*field) &&
+      list_tag ==
+          WireFormatLite::MakeTag(field->number(),
+                                  WireFormatLite::WIRETYPE_LENGTH_DELIMITED)) {
+    RETURN_IF_ERROR(RenderPacked(field, ow));
+    // Since packed fields have a single tag, read another tag from stream to
+    // return.
+    tag_to_return = stream_->ReadTag();
+  } else {
+    do {
+      RETURN_IF_ERROR(RenderField(field, "", ow));
+    } while ((tag_to_return = stream_->ReadTag()) == list_tag);
+  }
+  ow->EndList();
+  return tag_to_return;
+}
+
+StatusOr<uint32> ProtoStreamObjectSource::RenderMap(
+    const google::protobuf::Field* field, StringPiece name, uint32 list_tag,
+    ObjectWriter* ow) const {
+  const google::protobuf::Type* field_type =
+      typeinfo_->GetTypeByTypeUrl(field->type_url());
+  uint32 tag_to_return = 0;
+  do {
+    // Render map entry message type.
+    uint32 buffer32;
+    stream_->ReadVarint32(&buffer32);  // message length
+    int old_limit = stream_->PushLimit(buffer32);
+    string map_key;
+    for (uint32 tag = stream_->ReadTag(); tag != 0; tag = stream_->ReadTag()) {
+      const google::protobuf::Field* field =
+          FindAndVerifyField(*field_type, tag);
+      if (field == NULL) {
+        WireFormat::SkipField(stream_, tag, NULL);
+        continue;
+      }
+      // Map field numbers are key = 1 and value = 2
+      if (field->number() == 1) {
+        map_key = ReadFieldValueAsString(*field);
+      } else if (field->number() == 2) {
+        if (map_key.empty()) {
+          return Status(util::error::INTERNAL, "Map key must be non-empty");
+        }
+        RETURN_IF_ERROR(RenderField(field, map_key, ow));
+      }
+    }
+    stream_->PopLimit(old_limit);
+  } while ((tag_to_return = stream_->ReadTag()) == list_tag);
+  return tag_to_return;
+}
+
+Status ProtoStreamObjectSource::RenderPacked(
+    const google::protobuf::Field* field, ObjectWriter* ow) const {
+  uint32 length;
+  stream_->ReadVarint32(&length);
+  int old_limit = stream_->PushLimit(length);
+  while (stream_->BytesUntilLimit() > 0) {
+    RETURN_IF_ERROR(RenderField(field, StringPiece(), ow));
+  }
+  stream_->PopLimit(old_limit);
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderTimestamp(
+    const ProtoStreamObjectSource* os, const google::protobuf::Type& type,
+    StringPiece field_name, ObjectWriter* ow) {
+  pair<int64, int32> p = os->ReadSecondsAndNanos(type);
+  int64 seconds = p.first;
+  int32 nanos = p.second;
+  if (seconds > kMaxSeconds || seconds < kMinSeconds) {
+    return Status(
+        util::error::INTERNAL,
+        StrCat("Timestamp seconds exceeds limit for field: ", field_name));
+  }
+
+  if (nanos < 0 || nanos >= kNanosPerSecond) {
+    return Status(
+        util::error::INTERNAL,
+        StrCat("Timestamp nanos exceeds limit for field: ", field_name));
+  }
+
+  ow->RenderString(field_name,
+                   ::google::protobuf::internal::FormatTime(seconds, nanos));
+
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderDuration(
+    const ProtoStreamObjectSource* os, const google::protobuf::Type& type,
+    StringPiece field_name, ObjectWriter* ow) {
+  pair<int64, int32> p = os->ReadSecondsAndNanos(type);
+  int64 seconds = p.first;
+  int32 nanos = p.second;
+  if (seconds > kMaxSeconds || seconds < kMinSeconds) {
+    return Status(
+        util::error::INTERNAL,
+        StrCat("Duration seconds exceeds limit for field: ", field_name));
+  }
+
+  if (nanos <= -kNanosPerSecond || nanos >= kNanosPerSecond) {
+    return Status(
+        util::error::INTERNAL,
+        StrCat("Duration nanos exceeds limit for field: ", field_name));
+  }
+
+  string sign = "";
+  if (seconds < 0) {
+    if (nanos > 0) {
+      return Status(util::error::INTERNAL,
+                    StrCat("Duration nanos is non-negative, but seconds is "
+                           "negative for field: ",
+                           field_name));
+    }
+    sign = "-";
+    seconds = -seconds;
+    nanos = -nanos;
+  } else if (seconds == 0 && nanos < 0) {
+    sign = "-";
+    nanos = -nanos;
+  }
+  string formatted_duration = StringPrintf("%s%lld%ss", sign.c_str(), seconds,
+                                           FormatNanos(nanos).c_str());
+  ow->RenderString(field_name, formatted_duration);
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderDouble(const ProtoStreamObjectSource* os,
+                                             const google::protobuf::Type& type,
+                                             StringPiece field_name,
+                                             ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+  uint64 buffer64 = 0;  // default value of Double wrapper value
+  if (tag != 0) {
+    os->stream_->ReadLittleEndian64(&buffer64);
+    os->stream_->ReadTag();
+  }
+  ow->RenderDouble(field_name, bit_cast<double>(buffer64));
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderFloat(const ProtoStreamObjectSource* os,
+                                            const google::protobuf::Type& type,
+                                            StringPiece field_name,
+                                            ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+  uint32 buffer32 = 0;  // default value of Float wrapper value
+  if (tag != 0) {
+    os->stream_->ReadLittleEndian32(&buffer32);
+    os->stream_->ReadTag();
+  }
+  ow->RenderFloat(field_name, bit_cast<float>(buffer32));
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderInt64(const ProtoStreamObjectSource* os,
+                                            const google::protobuf::Type& type,
+                                            StringPiece field_name,
+                                            ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+  uint64 buffer64 = 0;  // default value of Int64 wrapper value
+  if (tag != 0) {
+    os->stream_->ReadVarint64(&buffer64);
+    os->stream_->ReadTag();
+  }
+  ow->RenderInt64(field_name, bit_cast<int64>(buffer64));
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderUInt64(const ProtoStreamObjectSource* os,
+                                             const google::protobuf::Type& type,
+                                             StringPiece field_name,
+                                             ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+  uint64 buffer64 = 0;  // default value of UInt64 wrapper value
+  if (tag != 0) {
+    os->stream_->ReadVarint64(&buffer64);
+    os->stream_->ReadTag();
+  }
+  ow->RenderUint64(field_name, bit_cast<uint64>(buffer64));
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderInt32(const ProtoStreamObjectSource* os,
+                                            const google::protobuf::Type& type,
+                                            StringPiece field_name,
+                                            ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+  uint32 buffer32 = 0;  // default value of Int32 wrapper value
+  if (tag != 0) {
+    os->stream_->ReadVarint32(&buffer32);
+    os->stream_->ReadTag();
+  }
+  ow->RenderInt32(field_name, bit_cast<int32>(buffer32));
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderUInt32(const ProtoStreamObjectSource* os,
+                                             const google::protobuf::Type& type,
+                                             StringPiece field_name,
+                                             ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+  uint32 buffer32 = 0;  // default value of UInt32 wrapper value
+  if (tag != 0) {
+    os->stream_->ReadVarint32(&buffer32);
+    os->stream_->ReadTag();
+  }
+  ow->RenderUint32(field_name, bit_cast<uint32>(buffer32));
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderBool(const ProtoStreamObjectSource* os,
+                                           const google::protobuf::Type& type,
+                                           StringPiece field_name,
+                                           ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+  uint64 buffer64 = 0;  // results in 'false' value as default, which is the
+                        // default value of Bool wrapper
+  if (tag != 0) {
+    os->stream_->ReadVarint64(&buffer64);
+    os->stream_->ReadTag();
+  }
+  ow->RenderBool(field_name, buffer64 != 0);
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderString(const ProtoStreamObjectSource* os,
+                                             const google::protobuf::Type& type,
+                                             StringPiece field_name,
+                                             ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+  uint32 buffer32;
+  string str;  // default value of empty for String wrapper
+  if (tag != 0) {
+    os->stream_->ReadVarint32(&buffer32);  // string size.
+    os->stream_->ReadString(&str, buffer32);
+    os->stream_->ReadTag();
+  }
+  ow->RenderString(field_name, str);
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderBytes(const ProtoStreamObjectSource* os,
+                                            const google::protobuf::Type& type,
+                                            StringPiece field_name,
+                                            ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+  uint32 buffer32;
+  string str;
+  if (tag != 0) {
+    os->stream_->ReadVarint32(&buffer32);
+    os->stream_->ReadString(&str, buffer32);
+    os->stream_->ReadTag();
+  }
+  ow->RenderBytes(field_name, str);
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderStruct(const ProtoStreamObjectSource* os,
+                                             const google::protobuf::Type& type,
+                                             StringPiece field_name,
+                                             ObjectWriter* ow) {
+  const google::protobuf::Field* field = NULL;
+  uint32 tag = os->stream_->ReadTag();
+  ow->StartObject(field_name);
+  while (tag != 0) {
+    field = os->FindAndVerifyField(type, tag);
+    // google.protobuf.Struct has only one field that is a map. Hence we use
+    // RenderMap to render that field.
+    if (os->IsMap(*field)) {
+      ASSIGN_OR_RETURN(tag, os->RenderMap(field, field_name, tag, ow));
+    }
+  }
+  ow->EndObject();
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderStructValue(
+    const ProtoStreamObjectSource* os, const google::protobuf::Type& type,
+    StringPiece field_name, ObjectWriter* ow) {
+  const google::protobuf::Field* field = NULL;
+  for (uint32 tag = os->stream_->ReadTag(); tag != 0;
+       tag = os->stream_->ReadTag()) {
+    field = os->FindAndVerifyField(type, tag);
+    if (field == NULL) {
+      WireFormat::SkipField(os->stream_, tag, NULL);
+      continue;
+    }
+    RETURN_IF_ERROR(os->RenderField(field, field_name, ow));
+  }
+  return Status::OK;
+}
+
+// TODO(skarvaje): Avoid code duplication of for loops and SkipField logic.
+Status ProtoStreamObjectSource::RenderStructListValue(
+    const ProtoStreamObjectSource* os, const google::protobuf::Type& type,
+    StringPiece field_name, ObjectWriter* ow) {
+  uint32 tag = os->stream_->ReadTag();
+
+  // Render empty list when we find empty ListValue message.
+  if (tag == 0) {
+    ow->StartList(field_name);
+    ow->EndList();
+    return Status::OK;
+  }
+
+  while (tag != 0) {
+    const google::protobuf::Field* field = os->FindAndVerifyField(type, tag);
+    if (field == NULL) {
+      WireFormat::SkipField(os->stream_, tag, NULL);
+      tag = os->stream_->ReadTag();
+      continue;
+    }
+    ASSIGN_OR_RETURN(tag, os->RenderList(field, field_name, tag, ow));
+  }
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderAny(const ProtoStreamObjectSource* os,
+                                          const google::protobuf::Type& type,
+                                          StringPiece field_name,
+                                          ObjectWriter* ow) {
+  // An Any is of the form { string type_url = 1; bytes value = 2; }
+  uint32 tag;
+  string type_url;
+  string value;
+
+  // First read out the type_url and value from the proto stream
+  for (tag = os->stream_->ReadTag(); tag != 0; tag = os->stream_->ReadTag()) {
+    const google::protobuf::Field* field = os->FindAndVerifyField(type, tag);
+    if (field == NULL) {
+      WireFormat::SkipField(os->stream_, tag, NULL);
+      continue;
+    }
+    // 'type_url' has field number of 1 and 'value' has field number 2
+    // //google/protobuf/any.proto
+    if (field->number() == 1) {
+      // read type_url
+      uint32 type_url_size;
+      os->stream_->ReadVarint32(&type_url_size);
+      os->stream_->ReadString(&type_url, type_url_size);
+    } else if (field->number() == 2) {
+      // read value
+      uint32 value_size;
+      os->stream_->ReadVarint32(&value_size);
+      os->stream_->ReadString(&value, value_size);
+    }
+  }
+
+  // If there is no value, we don't lookup the type, we just output it (if
+  // present). If both type and value are empty we output an empty object.
+  if (value.empty()) {
+    ow->StartObject(field_name);
+    if (!type_url.empty()) {
+      ow->RenderString("@type", type_url);
+    }
+    ow->EndObject();
+    return util::Status::OK;
+  }
+
+  // If there is a value but no type, we cannot render it, so report an error.
+  if (type_url.empty()) {
+    // TODO(sven): Add an external message once those are ready.
+    return util::Status(util::error::INTERNAL,
+                        "Invalid Any, the type_url is missing.");
+  }
+
+  util::StatusOr<const google::protobuf::Type*> resolved_type =
+      os->typeinfo_->ResolveTypeUrl(type_url);
+
+  if (!resolved_type.ok()) {
+    // Convert into an internal error, since this means the backend gave us
+    // an invalid response (missing or invalid type information).
+    return util::Status(util::error::INTERNAL,
+                        resolved_type.status().error_message());
+  }
+  // nested_type cannot be null at this time.
+  const google::protobuf::Type* nested_type = resolved_type.ValueOrDie();
+
+  google::protobuf::io::ArrayInputStream zero_copy_stream(value.data(), value.size());
+  google::protobuf::io::CodedInputStream in_stream(&zero_copy_stream);
+  // We know the type so we can render it. Recursively parse the nested stream
+  // using a nested ProtoStreamObjectSource using our nested type information.
+  ProtoStreamObjectSource nested_os(&in_stream, os->typeinfo_, *nested_type);
+
+  // We manually call start and end object here so we can inject the @type.
+  ow->StartObject(field_name);
+  ow->RenderString("@type", type_url);
+  util::Status result =
+      nested_os.WriteMessage(nested_os.type_, "value", 0, false, ow);
+  ow->EndObject();
+  return result;
+}
+
+Status ProtoStreamObjectSource::RenderFieldMask(
+    const ProtoStreamObjectSource* os, const google::protobuf::Type& type,
+    StringPiece field_name, ObjectWriter* ow) {
+  string combined;
+  uint32 buffer32;
+  uint32 paths_field_tag = 0;
+  for (uint32 tag = os->stream_->ReadTag(); tag != 0;
+       tag = os->stream_->ReadTag()) {
+    if (paths_field_tag == 0) {
+      const google::protobuf::Field* field = os->FindAndVerifyField(type, tag);
+      if (field != NULL && field->number() == 1 &&
+          field->name() == "paths") {
+        paths_field_tag = tag;
+      }
+    }
+    if (paths_field_tag != tag) {
+      return util::Status(util::error::INTERNAL,
+                          "Invalid FieldMask, unexpected field.");
+    }
+    string str;
+    os->stream_->ReadVarint32(&buffer32);  // string size.
+    os->stream_->ReadString(&str, buffer32);
+    if (!combined.empty()) {
+      combined.append(",");
+    }
+    combined.append(ConvertFieldMaskPath(str, &ToCamelCase));
+  }
+  ow->RenderString(field_name, combined);
+  return Status::OK;
+}
+
+
+hash_map<string, ProtoStreamObjectSource::TypeRenderer>*
+    ProtoStreamObjectSource::renderers_ = NULL;
+GOOGLE_PROTOBUF_DECLARE_ONCE(source_renderers_init_);
+
+void ProtoStreamObjectSource::InitRendererMap() {
+  renderers_ = new hash_map<string, ProtoStreamObjectSource::TypeRenderer>();
+  (*renderers_)["google.protobuf.Timestamp"] =
+      &ProtoStreamObjectSource::RenderTimestamp;
+  (*renderers_)["google.protobuf.Duration"] =
+      &ProtoStreamObjectSource::RenderDuration;
+  (*renderers_)["google.protobuf.DoubleValue"] =
+      &ProtoStreamObjectSource::RenderDouble;
+  (*renderers_)["google.protobuf.FloatValue"] =
+      &ProtoStreamObjectSource::RenderFloat;
+  (*renderers_)["google.protobuf.Int64Value"] =
+      &ProtoStreamObjectSource::RenderInt64;
+  (*renderers_)["google.protobuf.UInt64Value"] =
+      &ProtoStreamObjectSource::RenderUInt64;
+  (*renderers_)["google.protobuf.Int32Value"] =
+      &ProtoStreamObjectSource::RenderInt32;
+  (*renderers_)["google.protobuf.UInt32Value"] =
+      &ProtoStreamObjectSource::RenderUInt32;
+  (*renderers_)["google.protobuf.BoolValue"] =
+      &ProtoStreamObjectSource::RenderBool;
+  (*renderers_)["google.protobuf.StringValue"] =
+      &ProtoStreamObjectSource::RenderString;
+  (*renderers_)["google.protobuf.BytesValue"] =
+      &ProtoStreamObjectSource::RenderBytes;
+  (*renderers_)["google.protobuf.Any"] = &ProtoStreamObjectSource::RenderAny;
+  (*renderers_)["google.protobuf.Struct"] =
+      &ProtoStreamObjectSource::RenderStruct;
+  (*renderers_)["google.protobuf.Value"] =
+      &ProtoStreamObjectSource::RenderStructValue;
+  (*renderers_)["google.protobuf.ListValue"] =
+      &ProtoStreamObjectSource::RenderStructListValue;
+  (*renderers_)["google.protobuf.FieldMask"] =
+      &ProtoStreamObjectSource::RenderFieldMask;
+  ::google::protobuf::internal::OnShutdown(&DeleteRendererMap);
+}
+
+void ProtoStreamObjectSource::DeleteRendererMap() {
+  delete ProtoStreamObjectSource::renderers_;
+  renderers_ = NULL;
+}
+
+// static
+ProtoStreamObjectSource::TypeRenderer*
+ProtoStreamObjectSource::FindTypeRenderer(const string& type_url) {
+  ::google::protobuf::GoogleOnceInit(&source_renderers_init_, &InitRendererMap);
+  return FindOrNull(*renderers_, type_url);
+}
+
+Status ProtoStreamObjectSource::RenderField(
+    const google::protobuf::Field* field, StringPiece field_name,
+    ObjectWriter* ow) const {
+  // Short-circuit message types as it tends to call WriteMessage recursively
+  // and ends up using a lot of stack space. Keep the stack usage of this
+  // message small in order to preserve stack space and not crash.
+  if (field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE) {
+    uint32 buffer32;
+    stream_->ReadVarint32(&buffer32);  // message length
+    int old_limit = stream_->PushLimit(buffer32);
+    // Get the nested message type for this field.
+    const google::protobuf::Type* type =
+        typeinfo_->GetTypeByTypeUrl(field->type_url());
+    if (type == NULL) {
+      return Status(util::error::INTERNAL,
+                    StrCat("Invalid configuration. Could not find the type: ",
+                           field->type_url()));
+    }
+
+    // Short-circuit any special type rendering to save call-stack space.
+    const TypeRenderer* type_renderer = FindTypeRenderer(type->name());
+
+    bool use_type_renderer = type_renderer != NULL;
+
+    if (use_type_renderer) {
+      RETURN_IF_ERROR((*type_renderer)(this, *type, field_name, ow));
+    } else {
+      RETURN_IF_ERROR(WriteMessage(*type, field_name, 0, true, ow));
+    }
+    if (!stream_->ConsumedEntireMessage()) {
+      return Status(util::error::INVALID_ARGUMENT,
+                    "Nested protocol message not parsed in its entirety.");
+    }
+    stream_->PopLimit(old_limit);
+  } else {
+    // Render all other non-message types.
+    return RenderNonMessageField(field, field_name, ow);
+  }
+  return Status::OK;
+}
+
+Status ProtoStreamObjectSource::RenderNonMessageField(
+    const google::protobuf::Field* field, StringPiece field_name,
+    ObjectWriter* ow) const {
+  // Temporary buffers of different types.
+  uint32 buffer32;
+  uint64 buffer64;
+  string strbuffer;
+  switch (field->kind()) {
+    case google::protobuf::Field_Kind_TYPE_BOOL: {
+      stream_->ReadVarint64(&buffer64);
+      ow->RenderBool(field_name, buffer64 != 0);
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_INT32: {
+      stream_->ReadVarint32(&buffer32);
+      ow->RenderInt32(field_name, bit_cast<int32>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_INT64: {
+      stream_->ReadVarint64(&buffer64);
+      ow->RenderInt64(field_name, bit_cast<int64>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_UINT32: {
+      stream_->ReadVarint32(&buffer32);
+      ow->RenderUint32(field_name, bit_cast<uint32>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_UINT64: {
+      stream_->ReadVarint64(&buffer64);
+      ow->RenderUint64(field_name, bit_cast<uint64>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SINT32: {
+      stream_->ReadVarint32(&buffer32);
+      ow->RenderInt32(field_name, WireFormatLite::ZigZagDecode32(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SINT64: {
+      stream_->ReadVarint64(&buffer64);
+      ow->RenderInt64(field_name, WireFormatLite::ZigZagDecode64(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SFIXED32: {
+      stream_->ReadLittleEndian32(&buffer32);
+      ow->RenderInt32(field_name, bit_cast<int32>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SFIXED64: {
+      stream_->ReadLittleEndian64(&buffer64);
+      ow->RenderInt64(field_name, bit_cast<int64>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FIXED32: {
+      stream_->ReadLittleEndian32(&buffer32);
+      ow->RenderUint32(field_name, bit_cast<uint32>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FIXED64: {
+      stream_->ReadLittleEndian64(&buffer64);
+      ow->RenderUint64(field_name, bit_cast<uint64>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FLOAT: {
+      stream_->ReadLittleEndian32(&buffer32);
+      ow->RenderFloat(field_name, bit_cast<float>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_DOUBLE: {
+      stream_->ReadLittleEndian64(&buffer64);
+      ow->RenderDouble(field_name, bit_cast<double>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_ENUM: {
+      stream_->ReadVarint32(&buffer32);
+
+      // If the field represents an explicit NULL value, render null.
+      if (field->type_url() == kStructNullValueTypeUrl) {
+        ow->RenderNull(field_name);
+        break;
+      }
+
+      // Get the nested enum type for this field.
+      // TODO(skarvaje): Avoid string manipulation. Find ways to speed this
+      // up.
+      const google::protobuf::Enum* en =
+          typeinfo_->GetEnumByTypeUrl(field->type_url());
+      // Lookup the name of the enum, and render that. Skips unknown enums.
+      if (en != NULL) {
+        const google::protobuf::EnumValue* enum_value =
+            FindEnumValueByNumber(*en, buffer32);
+        if (enum_value != NULL) {
+          ow->RenderString(field_name, enum_value->name());
+        }
+      } else {
+        GOOGLE_LOG(INFO) << "Unknown enum skipped: " << field->type_url();
+      }
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_STRING: {
+      stream_->ReadVarint32(&buffer32);  // string size.
+      stream_->ReadString(&strbuffer, buffer32);
+      ow->RenderString(field_name, strbuffer);
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_BYTES: {
+      stream_->ReadVarint32(&buffer32);  // bytes size.
+      stream_->ReadString(&strbuffer, buffer32);
+      ow->RenderBytes(field_name, strbuffer);
+      break;
+    }
+    default:
+      break;
+  }
+  return Status::OK;
+}
+
+// TODO(skarvaje): Fix this to avoid code duplication.
+const string ProtoStreamObjectSource::ReadFieldValueAsString(
+    const google::protobuf::Field& field) const {
+  string result;
+  switch (field.kind()) {
+    case google::protobuf::Field_Kind_TYPE_BOOL: {
+      uint64 buffer64;
+      stream_->ReadVarint64(&buffer64);
+      result = buffer64 != 0 ? "true" : "false";
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_INT32: {
+      uint32 buffer32;
+      stream_->ReadVarint32(&buffer32);
+      result = SimpleItoa(bit_cast<int32>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_INT64: {
+      uint64 buffer64;
+      stream_->ReadVarint64(&buffer64);
+      result = SimpleItoa(bit_cast<int64>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_UINT32: {
+      uint32 buffer32;
+      stream_->ReadVarint32(&buffer32);
+      result = SimpleItoa(bit_cast<uint32>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_UINT64: {
+      uint64 buffer64;
+      stream_->ReadVarint64(&buffer64);
+      result = SimpleItoa(bit_cast<uint64>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SINT32: {
+      uint32 buffer32;
+      stream_->ReadVarint32(&buffer32);
+      result = SimpleItoa(WireFormatLite::ZigZagDecode32(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SINT64: {
+      uint64 buffer64;
+      stream_->ReadVarint64(&buffer64);
+      result = SimpleItoa(WireFormatLite::ZigZagDecode64(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SFIXED32: {
+      uint32 buffer32;
+      stream_->ReadLittleEndian32(&buffer32);
+      result = SimpleItoa(bit_cast<int32>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SFIXED64: {
+      uint64 buffer64;
+      stream_->ReadLittleEndian64(&buffer64);
+      result = SimpleItoa(bit_cast<int64>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FIXED32: {
+      uint32 buffer32;
+      stream_->ReadLittleEndian32(&buffer32);
+      result = SimpleItoa(bit_cast<uint32>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FIXED64: {
+      uint64 buffer64;
+      stream_->ReadLittleEndian64(&buffer64);
+      result = SimpleItoa(bit_cast<uint64>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FLOAT: {
+      uint32 buffer32;
+      stream_->ReadLittleEndian32(&buffer32);
+      result = SimpleFtoa(bit_cast<float>(buffer32));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_DOUBLE: {
+      uint64 buffer64;
+      stream_->ReadLittleEndian64(&buffer64);
+      result = SimpleDtoa(bit_cast<double>(buffer64));
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_ENUM: {
+      uint32 buffer32;
+      stream_->ReadVarint32(&buffer32);
+      // Get the nested enum type for this field.
+      // TODO(skarvaje): Avoid string manipulation. Find ways to speed this
+      // up.
+      const google::protobuf::Enum* en =
+          typeinfo_->GetEnumByTypeUrl(field.type_url());
+      // Lookup the name of the enum, and render that. Skips unknown enums.
+      if (en != NULL) {
+        const google::protobuf::EnumValue* enum_value =
+            FindEnumValueByNumber(*en, buffer32);
+        if (enum_value != NULL) {
+          result = enum_value->name();
+        }
+      }
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_STRING: {
+      uint32 buffer32;
+      stream_->ReadVarint32(&buffer32);  // string size.
+      stream_->ReadString(&result, buffer32);
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_BYTES: {
+      uint32 buffer32;
+      stream_->ReadVarint32(&buffer32);  // bytes size.
+      stream_->ReadString(&result, buffer32);
+      break;
+    }
+    default:
+      break;
+  }
+  return result;
+}
+
+// Field is a map if it is a repeated message and it has an option "map_type".
+// TODO(skarvaje): Consider pre-computing the IsMap() into Field directly.
+bool ProtoStreamObjectSource::IsMap(
+    const google::protobuf::Field& field) const {
+  const google::protobuf::Type* field_type =
+      typeinfo_->GetTypeByTypeUrl(field.type_url());
+
+  // TODO(xiaofeng): Unify option names.
+  return field.kind() == google::protobuf::Field_Kind_TYPE_MESSAGE &&
+         (GetBoolOptionOrDefault(field_type->options(),
+                                 "google.protobuf.MessageOptions.map_entry", false) ||
+          GetBoolOptionOrDefault(field_type->options(), "map_entry", false));
+}
+
+std::pair<int64, int32> ProtoStreamObjectSource::ReadSecondsAndNanos(
+    const google::protobuf::Type& type) const {
+  uint64 seconds = 0;
+  uint32 nanos = 0;
+  uint32 tag = 0;
+  int64 signed_seconds = 0;
+  int32 signed_nanos = 0;
+
+  for (tag = stream_->ReadTag(); tag != 0; tag = stream_->ReadTag()) {
+    const google::protobuf::Field* field = FindAndVerifyField(type, tag);
+    if (field == NULL) {
+      WireFormat::SkipField(stream_, tag, NULL);
+      continue;
+    }
+    // 'seconds' has field number of 1 and 'nanos' has field number 2
+    // //google/protobuf/timestamp.proto & duration.proto
+    if (field->number() == 1) {
+      // read seconds
+      stream_->ReadVarint64(&seconds);
+      signed_seconds = bit_cast<int64>(seconds);
+    } else if (field->number() == 2) {
+      // read nanos
+      stream_->ReadVarint32(&nanos);
+      signed_nanos = bit_cast<int32>(nanos);
+    }
+  }
+  return std::pair<int64, int32>(signed_seconds, signed_nanos);
+}
+
+namespace {
+// TODO(skarvaje): Speed this up by not doing a linear scan.
+const google::protobuf::Field* FindFieldByNumber(
+    const google::protobuf::Type& type, int number) {
+  for (int i = 0; i < type.fields_size(); ++i) {
+    if (type.fields(i).number() == number) {
+      return &type.fields(i);
+    }
+  }
+  return NULL;
+}
+
+// TODO(skarvaje): Replace FieldDescriptor by implementing IsTypePackable()
+// using tech Field.
+bool IsPackable(const google::protobuf::Field& field) {
+  return field.cardinality() ==
+             google::protobuf::Field_Cardinality_CARDINALITY_REPEATED &&
+         google::protobuf::FieldDescriptor::IsTypePackable(
+             static_cast<google::protobuf::FieldDescriptor::Type>(field.kind()));
+}
+
+// TODO(skarvaje): Speed this up by not doing a linear scan.
+const google::protobuf::EnumValue* FindEnumValueByNumber(
+    const google::protobuf::Enum& tech_enum, int number) {
+  for (int i = 0; i < tech_enum.enumvalue_size(); ++i) {
+    const google::protobuf::EnumValue& ev = tech_enum.enumvalue(i);
+    if (ev.number() == number) {
+      return &ev;
+    }
+  }
+  return NULL;
+}
+
+// TODO(skarvaje): Look into optimizing this by not doing computation on
+// double.
+const string FormatNanos(uint32 nanos) {
+  const char* format =
+      (nanos % 1000 != 0) ? "%.9f" : (nanos % 1000000 != 0) ? "%.6f" : "%.3f";
+  string formatted =
+      StringPrintf(format, static_cast<double>(nanos) / kNanosPerSecond);
+  // remove the leading 0 before decimal.
+  return formatted.substr(1);
+}
+}  // namespace
+
+}  // namespace converter
+}  // namespace util
+}  // namespace protobuf
+}  // namespace google