Update //third_party/protobuf to version 3.

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

Index: third_party/protobuf/src/google/protobuf/util/internal/proto_writer.cc
diff --git a/third_party/protobuf/src/google/protobuf/util/internal/proto_writer.cc b/third_party/protobuf/src/google/protobuf/util/internal/proto_writer.cc
new file mode 100644
index 0000000000000000000000000000000000000000..47e0009ec369ac7577f7e6b72de6e771cc891071
--- /dev/null
+++ b/third_party/protobuf/src/google/protobuf/util/internal/proto_writer.cc
@@ -0,0 +1,744 @@
+// 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/proto_writer.h>
+
+#include <functional>
+#include <stack>
+
+#include <google/protobuf/stubs/once.h>
+#include <google/protobuf/stubs/time.h>
+#include <google/protobuf/wire_format_lite.h>
+#include <google/protobuf/util/internal/field_mask_utility.h>
+#include <google/protobuf/util/internal/object_location_tracker.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/statusor.h>
+
+
+namespace google {
+namespace protobuf {
+namespace util {
+namespace converter {
+
+using google::protobuf::internal::WireFormatLite;
+using google::protobuf::io::CodedOutputStream;
+using util::error::INVALID_ARGUMENT;
+using util::Status;
+using util::StatusOr;
+
+
+ProtoWriter::ProtoWriter(TypeResolver* type_resolver,
+                         const google::protobuf::Type& type,
+                         strings::ByteSink* output, ErrorListener* listener)
+    : master_type_(type),
+      typeinfo_(TypeInfo::NewTypeInfo(type_resolver)),
+      own_typeinfo_(true),
+      done_(false),
+      element_(NULL),
+      size_insert_(),
+      output_(output),
+      buffer_(),
+      adapter_(&buffer_),
+      stream_(new CodedOutputStream(&adapter_)),
+      listener_(listener),
+      invalid_depth_(0),
+      tracker_(new ObjectLocationTracker()) {}
+
+ProtoWriter::ProtoWriter(const TypeInfo* typeinfo,
+                         const google::protobuf::Type& type,
+                         strings::ByteSink* output, ErrorListener* listener)
+    : master_type_(type),
+      typeinfo_(typeinfo),
+      own_typeinfo_(false),
+      done_(false),
+      element_(NULL),
+      size_insert_(),
+      output_(output),
+      buffer_(),
+      adapter_(&buffer_),
+      stream_(new CodedOutputStream(&adapter_)),
+      listener_(listener),
+      invalid_depth_(0),
+      tracker_(new ObjectLocationTracker()) {}
+
+ProtoWriter::~ProtoWriter() {
+  if (own_typeinfo_) {
+    delete typeinfo_;
+  }
+  if (element_ == NULL) return;
+  // Cleanup explicitly in order to avoid destructor stack overflow when input
+  // is deeply nested.
+  // Cast to BaseElement to avoid doing additional checks (like missing fields)
+  // during pop().
+  google::protobuf::scoped_ptr<BaseElement> element(
+      static_cast<BaseElement*>(element_.get())->pop<BaseElement>());
+  while (element != NULL) {
+    element.reset(element->pop<BaseElement>());
+  }
+}
+
+namespace {
+
+// Writes an INT32 field, including tag to the stream.
+inline Status WriteInt32(int field_number, const DataPiece& data,
+                         CodedOutputStream* stream) {
+  StatusOr<int32> i32 = data.ToInt32();
+  if (i32.ok()) {
+    WireFormatLite::WriteInt32(field_number, i32.ValueOrDie(), stream);
+  }
+  return i32.status();
+}
+
+// writes an SFIXED32 field, including tag, to the stream.
+inline Status WriteSFixed32(int field_number, const DataPiece& data,
+                            CodedOutputStream* stream) {
+  StatusOr<int32> i32 = data.ToInt32();
+  if (i32.ok()) {
+    WireFormatLite::WriteSFixed32(field_number, i32.ValueOrDie(), stream);
+  }
+  return i32.status();
+}
+
+// Writes an SINT32 field, including tag, to the stream.
+inline Status WriteSInt32(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<int32> i32 = data.ToInt32();
+  if (i32.ok()) {
+    WireFormatLite::WriteSInt32(field_number, i32.ValueOrDie(), stream);
+  }
+  return i32.status();
+}
+
+// Writes a FIXED32 field, including tag, to the stream.
+inline Status WriteFixed32(int field_number, const DataPiece& data,
+                           CodedOutputStream* stream) {
+  StatusOr<uint32> u32 = data.ToUint32();
+  if (u32.ok()) {
+    WireFormatLite::WriteFixed32(field_number, u32.ValueOrDie(), stream);
+  }
+  return u32.status();
+}
+
+// Writes a UINT32 field, including tag, to the stream.
+inline Status WriteUInt32(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<uint32> u32 = data.ToUint32();
+  if (u32.ok()) {
+    WireFormatLite::WriteUInt32(field_number, u32.ValueOrDie(), stream);
+  }
+  return u32.status();
+}
+
+// Writes an INT64 field, including tag, to the stream.
+inline Status WriteInt64(int field_number, const DataPiece& data,
+                         CodedOutputStream* stream) {
+  StatusOr<int64> i64 = data.ToInt64();
+  if (i64.ok()) {
+    WireFormatLite::WriteInt64(field_number, i64.ValueOrDie(), stream);
+  }
+  return i64.status();
+}
+
+// Writes an SFIXED64 field, including tag, to the stream.
+inline Status WriteSFixed64(int field_number, const DataPiece& data,
+                            CodedOutputStream* stream) {
+  StatusOr<int64> i64 = data.ToInt64();
+  if (i64.ok()) {
+    WireFormatLite::WriteSFixed64(field_number, i64.ValueOrDie(), stream);
+  }
+  return i64.status();
+}
+
+// Writes an SINT64 field, including tag, to the stream.
+inline Status WriteSInt64(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<int64> i64 = data.ToInt64();
+  if (i64.ok()) {
+    WireFormatLite::WriteSInt64(field_number, i64.ValueOrDie(), stream);
+  }
+  return i64.status();
+}
+
+// Writes a FIXED64 field, including tag, to the stream.
+inline Status WriteFixed64(int field_number, const DataPiece& data,
+                           CodedOutputStream* stream) {
+  StatusOr<uint64> u64 = data.ToUint64();
+  if (u64.ok()) {
+    WireFormatLite::WriteFixed64(field_number, u64.ValueOrDie(), stream);
+  }
+  return u64.status();
+}
+
+// Writes a UINT64 field, including tag, to the stream.
+inline Status WriteUInt64(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<uint64> u64 = data.ToUint64();
+  if (u64.ok()) {
+    WireFormatLite::WriteUInt64(field_number, u64.ValueOrDie(), stream);
+  }
+  return u64.status();
+}
+
+// Writes a DOUBLE field, including tag, to the stream.
+inline Status WriteDouble(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<double> d = data.ToDouble();
+  if (d.ok()) {
+    WireFormatLite::WriteDouble(field_number, d.ValueOrDie(), stream);
+  }
+  return d.status();
+}
+
+// Writes a FLOAT field, including tag, to the stream.
+inline Status WriteFloat(int field_number, const DataPiece& data,
+                         CodedOutputStream* stream) {
+  StatusOr<float> f = data.ToFloat();
+  if (f.ok()) {
+    WireFormatLite::WriteFloat(field_number, f.ValueOrDie(), stream);
+  }
+  return f.status();
+}
+
+// Writes a BOOL field, including tag, to the stream.
+inline Status WriteBool(int field_number, const DataPiece& data,
+                        CodedOutputStream* stream) {
+  StatusOr<bool> b = data.ToBool();
+  if (b.ok()) {
+    WireFormatLite::WriteBool(field_number, b.ValueOrDie(), stream);
+  }
+  return b.status();
+}
+
+// Writes a BYTES field, including tag, to the stream.
+inline Status WriteBytes(int field_number, const DataPiece& data,
+                         CodedOutputStream* stream) {
+  StatusOr<string> c = data.ToBytes();
+  if (c.ok()) {
+    WireFormatLite::WriteBytes(field_number, c.ValueOrDie(), stream);
+  }
+  return c.status();
+}
+
+// Writes a STRING field, including tag, to the stream.
+inline Status WriteString(int field_number, const DataPiece& data,
+                          CodedOutputStream* stream) {
+  StatusOr<string> s = data.ToString();
+  if (s.ok()) {
+    WireFormatLite::WriteString(field_number, s.ValueOrDie(), stream);
+  }
+  return s.status();
+}
+
+// Writes an ENUM field, including tag, to the stream.
+inline Status WriteEnum(int field_number, const DataPiece& data,
+                        const google::protobuf::Enum* enum_type,
+                        CodedOutputStream* stream) {
+  StatusOr<int> e = data.ToEnum(enum_type);
+  if (e.ok()) {
+    WireFormatLite::WriteEnum(field_number, e.ValueOrDie(), stream);
+  }
+  return e.status();
+}
+
+// Given a google::protobuf::Type, returns the set of all required fields.
+std::set<const google::protobuf::Field*> GetRequiredFields(
+    const google::protobuf::Type& type) {
+  std::set<const google::protobuf::Field*> required;
+  for (int i = 0; i < type.fields_size(); i++) {
+    const google::protobuf::Field& field = type.fields(i);
+    if (field.cardinality() ==
+        google::protobuf::Field_Cardinality_CARDINALITY_REQUIRED) {
+      required.insert(&field);
+    }
+  }
+  return required;
+}
+
+}  // namespace
+
+ProtoWriter::ProtoElement::ProtoElement(const TypeInfo* typeinfo,
+                                        const google::protobuf::Type& type,
+                                        ProtoWriter* enclosing)
+    : BaseElement(NULL),
+      ow_(enclosing),
+      parent_field_(NULL),
+      typeinfo_(typeinfo),
+      type_(type),
+      required_fields_(GetRequiredFields(type)),
+      size_index_(-1),
+      array_index_(-1) {}
+
+ProtoWriter::ProtoElement::ProtoElement(ProtoWriter::ProtoElement* parent,
+                                        const google::protobuf::Field* field,
+                                        const google::protobuf::Type& type,
+                                        bool is_list)
+    : BaseElement(parent),
+      ow_(this->parent()->ow_),
+      parent_field_(field),
+      typeinfo_(this->parent()->typeinfo_),
+      type_(type),
+      size_index_(
+          !is_list && field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE
+              ? ow_->size_insert_.size()
+              : -1),
+      array_index_(is_list ? 0 : -1) {
+  if (!is_list) {
+    if (ow_->IsRepeated(*field)) {
+      // Update array_index_ if it is an explicit list.
+      if (this->parent()->array_index_ >= 0) this->parent()->array_index_++;
+    } else {
+      this->parent()->RegisterField(field);
+    }
+
+    if (field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE) {
+      required_fields_ = GetRequiredFields(type_);
+      int start_pos = ow_->stream_->ByteCount();
+      // length of serialized message is the final buffer position minus
+      // starting buffer position, plus length adjustments for size fields
+      // of any nested messages. We start with -start_pos here, so we only
+      // need to add the final buffer position to it at the end.
+      SizeInfo info = {start_pos, -start_pos};
+      ow_->size_insert_.push_back(info);
+    }
+  }
+}
+
+ProtoWriter::ProtoElement* ProtoWriter::ProtoElement::pop() {
+  // Calls the registered error listener for any required field(s) not yet
+  // seen.
+  for (set<const google::protobuf::Field*>::iterator it =
+           required_fields_.begin();
+       it != required_fields_.end(); ++it) {
+    ow_->MissingField((*it)->name());
+  }
+  // Computes the total number of proto bytes used by a message, also adjusts
+  // the size of all parent messages by the length of this size field.
+  // If size_index_ < 0, this is not a message, so no size field is added.
+  if (size_index_ >= 0) {
+    // Add the final buffer position to compute the total length of this
+    // serialized message. The stored value (before this addition) already
+    // contains the total length of the size fields of all nested messages
+    // minus the initial buffer position.
+    ow_->size_insert_[size_index_].size += ow_->stream_->ByteCount();
+    // Calculate the length required to serialize the size field of the
+    // message, and propagate this additional size information upward to
+    // all enclosing messages.
+    int size = ow_->size_insert_[size_index_].size;
+    int length = CodedOutputStream::VarintSize32(size);
+    for (ProtoElement* e = parent(); e != NULL; e = e->parent()) {
+      // Only nested messages have size field, lists do not have size field.
+      if (e->size_index_ >= 0) {
+        ow_->size_insert_[e->size_index_].size += length;
+      }
+    }
+  }
+  return BaseElement::pop<ProtoElement>();
+}
+
+void ProtoWriter::ProtoElement::RegisterField(
+    const google::protobuf::Field* field) {
+  if (!required_fields_.empty() &&
+      field->cardinality() ==
+          google::protobuf::Field_Cardinality_CARDINALITY_REQUIRED) {
+    required_fields_.erase(field);
+  }
+}
+
+string ProtoWriter::ProtoElement::ToString() const {
+  if (parent() == NULL) return "";
+  string loc = parent()->ToString();
+  if (!ow_->IsRepeated(*parent_field_) ||
+      parent()->parent_field_ != parent_field_) {
+    string name = parent_field_->name();
+    int i = 0;
+    while (i < name.size() && (ascii_isalnum(name[i]) || name[i] == '_')) ++i;
+    if (i > 0 && i == name.size()) {  // safe field name
+      if (loc.empty()) {
+        loc = name;
+      } else {
+        StrAppend(&loc, ".", name);
+      }
+    } else {
+      StrAppend(&loc, "[\"", CEscape(name), "\"]");
+    }
+  }
+  if (ow_->IsRepeated(*parent_field_) && array_index_ > 0) {
+    StrAppend(&loc, "[", array_index_ - 1, "]");
+  }
+  return loc.empty() ? "." : loc;
+}
+
+bool ProtoWriter::ProtoElement::IsOneofIndexTaken(int32 index) {
+  return ContainsKey(oneof_indices_, index);
+}
+
+void ProtoWriter::ProtoElement::TakeOneofIndex(int32 index) {
+  InsertIfNotPresent(&oneof_indices_, index);
+}
+
+void ProtoWriter::InvalidName(StringPiece unknown_name, StringPiece message) {
+  listener_->InvalidName(location(), ToSnakeCase(unknown_name), message);
+}
+
+void ProtoWriter::InvalidValue(StringPiece type_name, StringPiece value) {
+  listener_->InvalidValue(location(), type_name, value);
+}
+
+void ProtoWriter::MissingField(StringPiece missing_name) {
+  listener_->MissingField(location(), missing_name);
+}
+
+ProtoWriter* ProtoWriter::StartObject(StringPiece name) {
+  // Starting the root message. Create the root ProtoElement and return.
+  if (element_ == NULL) {
+    if (!name.empty()) {
+      InvalidName(name, "Root element should not be named.");
+    }
+    element_.reset(new ProtoElement(typeinfo_, master_type_, this));
+    return this;
+  }
+
+  const google::protobuf::Field* field = NULL;
+  field = BeginNamed(name, false);
+  if (field == NULL) return this;
+
+  // Check to see if this field is a oneof and that no oneof in that group has
+  // already been set.
+  if (!ValidOneof(*field, name)) {
+    ++invalid_depth_;
+    return this;
+  }
+
+  const google::protobuf::Type* type = LookupType(field);
+  if (type == NULL) {
+    ++invalid_depth_;
+    InvalidName(name,
+                StrCat("Missing descriptor for field: ", field->type_url()));
+    return this;
+  }
+
+    WriteTag(*field);
+  element_.reset(new ProtoElement(element_.release(), field, *type, false));
+  return this;
+}
+
+ProtoWriter* ProtoWriter::EndObject() {
+  if (invalid_depth_ > 0) {
+    --invalid_depth_;
+    return this;
+  }
+
+  if (element_ != NULL) {
+    element_.reset(element_->pop());
+  }
+
+
+  // If ending the root element,
+  // then serialize the full message with calculated sizes.
+  if (element_ == NULL) {
+    WriteRootMessage();
+  }
+  return this;
+}
+
+ProtoWriter* ProtoWriter::StartList(StringPiece name) {
+  const google::protobuf::Field* field = BeginNamed(name, true);
+  if (field == NULL) return this;
+
+  if (!ValidOneof(*field, name)) {
+    ++invalid_depth_;
+    return this;
+  }
+
+  const google::protobuf::Type* type = LookupType(field);
+  if (type == NULL) {
+    ++invalid_depth_;
+    InvalidName(name,
+                StrCat("Missing descriptor for field: ", field->type_url()));
+    return this;
+  }
+
+  element_.reset(new ProtoElement(element_.release(), field, *type, true));
+  return this;
+}
+
+ProtoWriter* ProtoWriter::EndList() {
+  if (invalid_depth_ > 0) {
+    --invalid_depth_;
+  } else if (element_ != NULL) {
+    element_.reset(element_->pop());
+  }
+  return this;
+}
+
+ProtoWriter* ProtoWriter::RenderDataPiece(StringPiece name,
+                                          const DataPiece& data) {
+  Status status;
+  if (invalid_depth_ > 0) return this;
+
+  const google::protobuf::Field* field = Lookup(name);
+  if (field == NULL) return this;
+
+  if (!ValidOneof(*field, name)) return this;
+
+  const google::protobuf::Type* type = LookupType(field);
+  if (type == NULL) {
+    InvalidName(name,
+                StrCat("Missing descriptor for field: ", field->type_url()));
+    return this;
+  }
+
+  // Pushing a ProtoElement and then pop it off at the end for 2 purposes:
+  // error location reporting and required field accounting.
+  element_.reset(new ProtoElement(element_.release(), field, *type, false));
+
+  if (field->kind() == google::protobuf::Field_Kind_TYPE_UNKNOWN ||
+      field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE) {
+    InvalidValue(field->type_url().empty()
+                     ? google::protobuf::Field_Kind_Name(field->kind())
+                     : field->type_url(),
+                 data.ValueAsStringOrDefault(""));
+    element_.reset(element()->pop());
+    return this;
+  }
+
+  switch (field->kind()) {
+    case google::protobuf::Field_Kind_TYPE_INT32: {
+      status = WriteInt32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SFIXED32: {
+      status = WriteSFixed32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SINT32: {
+      status = WriteSInt32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FIXED32: {
+      status = WriteFixed32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_UINT32: {
+      status = WriteUInt32(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_INT64: {
+      status = WriteInt64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SFIXED64: {
+      status = WriteSFixed64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_SINT64: {
+      status = WriteSInt64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FIXED64: {
+      status = WriteFixed64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_UINT64: {
+      status = WriteUInt64(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_DOUBLE: {
+      status = WriteDouble(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_FLOAT: {
+      status = WriteFloat(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_BOOL: {
+      status = WriteBool(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_BYTES: {
+      status = WriteBytes(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_STRING: {
+      status = WriteString(field->number(), data, stream_.get());
+      break;
+    }
+    case google::protobuf::Field_Kind_TYPE_ENUM: {
+      status = WriteEnum(field->number(), data,
+                         typeinfo_->GetEnumByTypeUrl(field->type_url()),
+                         stream_.get());
+      break;
+    }
+    default:  // TYPE_GROUP or TYPE_MESSAGE
+      status = Status(INVALID_ARGUMENT, data.ToString().ValueOrDie());
+  }
+
+  if (!status.ok()) {
+    InvalidValue(google::protobuf::Field_Kind_Name(field->kind()),
+                 status.error_message());
+  }
+
+  element_.reset(element()->pop());
+  return this;
+}
+
+bool ProtoWriter::ValidOneof(const google::protobuf::Field& field,
+                             StringPiece unnormalized_name) {
+  if (element_ == NULL) return true;
+
+  if (field.oneof_index() > 0) {
+    if (element_->IsOneofIndexTaken(field.oneof_index())) {
+      InvalidValue(
+          "oneof",
+          StrCat("oneof field '",
+                 element_->type().oneofs(field.oneof_index() - 1),
+                 "' is already set. Cannot set '", unnormalized_name, "'"));
+      return false;
+    }
+    element_->TakeOneofIndex(field.oneof_index());
+  }
+  return true;
+}
+
+bool ProtoWriter::IsRepeated(const google::protobuf::Field& field) {
+  return field.cardinality() ==
+         google::protobuf::Field_Cardinality_CARDINALITY_REPEATED;
+}
+
+const google::protobuf::Field* ProtoWriter::BeginNamed(StringPiece name,
+                                                       bool is_list) {
+  if (invalid_depth_ > 0) {
+    ++invalid_depth_;
+    return NULL;
+  }
+  const google::protobuf::Field* field = Lookup(name);
+  if (field == NULL) {
+    ++invalid_depth_;
+    // InvalidName() already called in Lookup().
+    return NULL;
+  }
+  if (is_list && !IsRepeated(*field)) {
+    ++invalid_depth_;
+    InvalidName(name, "Proto field is not repeating, cannot start list.");
+    return NULL;
+  }
+  return field;
+}
+
+const google::protobuf::Field* ProtoWriter::Lookup(
+    StringPiece unnormalized_name) {
+  ProtoElement* e = element();
+  if (e == NULL) {
+    InvalidName(unnormalized_name, "Root element must be a message.");
+    return NULL;
+  }
+  if (unnormalized_name.empty()) {
+    // Objects in repeated field inherit the same field descriptor.
+    if (e->parent_field() == NULL) {
+      InvalidName(unnormalized_name, "Proto fields must have a name.");
+    } else if (!IsRepeated(*e->parent_field())) {
+      InvalidName(unnormalized_name, "Proto fields must have a name.");
+      return NULL;
+    }
+    return e->parent_field();
+  }
+  const google::protobuf::Field* field =
+      typeinfo_->FindField(&e->type(), unnormalized_name);
+  if (field == NULL) InvalidName(unnormalized_name, "Cannot find field.");
+  return field;
+}
+
+const google::protobuf::Type* ProtoWriter::LookupType(
+    const google::protobuf::Field* field) {
+  return ((field->kind() == google::protobuf::Field_Kind_TYPE_MESSAGE ||
+           field->kind() == google::protobuf::Field_Kind_TYPE_GROUP)
+              ? typeinfo_->GetTypeByTypeUrl(field->type_url())
+              : &element_->type());
+}
+
+void ProtoWriter::WriteRootMessage() {
+  GOOGLE_DCHECK(!done_);
+  int curr_pos = 0;
+  // Calls the destructor of CodedOutputStream to remove any uninitialized
+  // memory from the Cord before we read it.
+  stream_.reset(NULL);
+  const void* data;
+  int length;
+  google::protobuf::io::ArrayInputStream input_stream(buffer_.data(), buffer_.size());
+  while (input_stream.Next(&data, &length)) {
+    if (length == 0) continue;
+    int num_bytes = length;
+    // Write up to where we need to insert the size field.
+    // The number of bytes we may write is the smaller of:
+    //   - the current fragment size
+    //   - the distance to the next position where a size field needs to be
+    //     inserted.
+    if (!size_insert_.empty() &&
+        size_insert_.front().pos - curr_pos < num_bytes) {
+      num_bytes = size_insert_.front().pos - curr_pos;
+    }
+    output_->Append(static_cast<const char*>(data), num_bytes);
+    if (num_bytes < length) {
+      input_stream.BackUp(length - num_bytes);
+    }
+    curr_pos += num_bytes;
+    // Insert the size field.
+    //   size_insert_.front():      the next <index, size> pair to be written.
+    //   size_insert_.front().pos:  position of the size field.
+    //   size_insert_.front().size: the size (integer) to be inserted.
+    if (!size_insert_.empty() && curr_pos == size_insert_.front().pos) {
+      // Varint32 occupies at most 10 bytes.
+      uint8 insert_buffer[10];
+      uint8* insert_buffer_pos = CodedOutputStream::WriteVarint32ToArray(
+          size_insert_.front().size, insert_buffer);
+      output_->Append(reinterpret_cast<const char*>(insert_buffer),
+                      insert_buffer_pos - insert_buffer);
+      size_insert_.pop_front();
+    }
+  }
+  output_->Flush();
+  stream_.reset(new CodedOutputStream(&adapter_));
+  done_ = true;
+}
+
+void ProtoWriter::WriteTag(const google::protobuf::Field& field) {
+  WireFormatLite::WireType wire_type = WireFormatLite::WireTypeForFieldType(
+      static_cast<WireFormatLite::FieldType>(field.kind()));
+  stream_->WriteTag(WireFormatLite::MakeTag(field.number(), wire_type));
+}
+
+
+}  // namespace converter
+}  // namespace util
+}  // namespace protobuf
+}  // namespace google