Update //third_party/protobuf to version 3.

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

Index: third_party/protobuf/src/google/protobuf/util/internal/protostream_objectwriter.cc
diff --git a/third_party/protobuf/src/google/protobuf/util/internal/protostream_objectwriter.cc b/third_party/protobuf/src/google/protobuf/util/internal/protostream_objectwriter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..786bf0be20d6446bc5767dac56c3dd6e30ab6f10
--- /dev/null
+++ b/third_party/protobuf/src/google/protobuf/util/internal/protostream_objectwriter.cc
@@ -0,0 +1,1133 @@
+// 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_objectwriter.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 util::error::INVALID_ARGUMENT;
+using util::Status;
+using util::StatusOr;
+
+
+ProtoStreamObjectWriter::ProtoStreamObjectWriter(
+    TypeResolver* type_resolver, const google::protobuf::Type& type,
+    strings::ByteSink* output, ErrorListener* listener)
+    : ProtoWriter(type_resolver, type, output, listener),
+      master_type_(type),
+      current_(NULL) {}
+
+ProtoStreamObjectWriter::ProtoStreamObjectWriter(
+    const TypeInfo* typeinfo, const google::protobuf::Type& type,
+    strings::ByteSink* output, ErrorListener* listener)
+    : ProtoWriter(typeinfo, type, output, listener),
+      master_type_(type),
+      current_(NULL) {}
+
+ProtoStreamObjectWriter::~ProtoStreamObjectWriter() {
+  if (current_ == 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*>(current_.get())->pop<BaseElement>());
+  while (element != NULL) {
+    element.reset(element->pop<BaseElement>());
+  }
+}
+
+namespace {
+// Utility method to split a string representation of Timestamp or Duration and
+// return the parts.
+void SplitSecondsAndNanos(StringPiece input, StringPiece* seconds,
+                          StringPiece* nanos) {
+  size_t idx = input.rfind('.');
+  if (idx != string::npos) {
+    *seconds = input.substr(0, idx);
+    *nanos = input.substr(idx + 1);
+  } else {
+    *seconds = input;
+    *nanos = StringPiece();
+  }
+}
+
+Status GetNanosFromStringPiece(StringPiece s_nanos,
+                               const char* parse_failure_message,
+                               const char* exceeded_limit_message,
+                               int32* nanos) {
+  *nanos = 0;
+
+  // Count the number of leading 0s and consume them.
+  int num_leading_zeros = 0;
+  while (s_nanos.Consume("0")) {
+    num_leading_zeros++;
+  }
+  int32 i_nanos = 0;
+  // 's_nanos' contains fractional seconds -- i.e. 'nanos' is equal to
+  // "0." + s_nanos.ToString() seconds. An int32 is used for the
+  // conversion to 'nanos', rather than a double, so that there is no
+  // loss of precision.
+  if (!s_nanos.empty() && !safe_strto32(s_nanos.ToString(), &i_nanos)) {
+    return Status(INVALID_ARGUMENT, parse_failure_message);
+  }
+  if (i_nanos > kNanosPerSecond || i_nanos < 0) {
+    return Status(INVALID_ARGUMENT, exceeded_limit_message);
+  }
+  // s_nanos should only have digits. No whitespace.
+  if (s_nanos.find_first_not_of("0123456789") != StringPiece::npos) {
+    return Status(INVALID_ARGUMENT, parse_failure_message);
+  }
+
+  if (i_nanos > 0) {
+    // 'scale' is the number of digits to the right of the decimal
+    // point in "0." + s_nanos.ToString()
+    int32 scale = num_leading_zeros + s_nanos.size();
+    // 'conversion' converts i_nanos into nanoseconds.
+    // conversion = kNanosPerSecond / static_cast<int32>(std::pow(10, scale))
+    // For efficiency, we precompute the conversion factor.
+    int32 conversion = 0;
+    switch (scale) {
+      case 1:
+        conversion = 100000000;
+        break;
+      case 2:
+        conversion = 10000000;
+        break;
+      case 3:
+        conversion = 1000000;
+        break;
+      case 4:
+        conversion = 100000;
+        break;
+      case 5:
+        conversion = 10000;
+        break;
+      case 6:
+        conversion = 1000;
+        break;
+      case 7:
+        conversion = 100;
+        break;
+      case 8:
+        conversion = 10;
+        break;
+      case 9:
+        conversion = 1;
+        break;
+      default:
+        return Status(INVALID_ARGUMENT, exceeded_limit_message);
+    }
+    *nanos = i_nanos * conversion;
+  }
+
+  return Status::OK;
+}
+
+}  // namespace
+
+ProtoStreamObjectWriter::AnyWriter::AnyWriter(ProtoStreamObjectWriter* parent)
+    : parent_(parent),
+      ow_(),
+      invalid_(false),
+      data_(),
+      output_(&data_),
+      depth_(0),
+      has_injected_value_message_(false) {}
+
+ProtoStreamObjectWriter::AnyWriter::~AnyWriter() {}
+
+void ProtoStreamObjectWriter::AnyWriter::StartObject(StringPiece name) {
+  ++depth_;
+  // If an object writer is absent, that means we have not called StartAny()
+  // before reaching here. This is an invalid state. StartAny() gets called
+  // whenever we see an "@type" being rendered (see AnyWriter::RenderDataPiece).
+  if (ow_ == NULL) {
+    // Make sure we are not already in an invalid state. This avoids making
+    // multiple unnecessary InvalidValue calls.
+    if (!invalid_) {
+      parent_->InvalidValue("Any",
+                            StrCat("Missing or invalid @type for any field in ",
+                                   parent_->master_type_.name()));
+      invalid_ = true;
+    }
+  } else if (!has_injected_value_message_ || depth_ != 1 || name != "value") {
+    // We don't propagate to ow_ StartObject("value") calls for nested Anys or
+    // Struct at depth 1 as they are nested one level deep with an injected
+    // "value" field.
+    ow_->StartObject(name);
+  }
+}
+
+bool ProtoStreamObjectWriter::AnyWriter::EndObject() {
+  --depth_;
+  // As long as depth_ >= 0, we know we haven't reached the end of Any.
+  // Propagate these EndObject() calls to the contained ow_.  If we are in a
+  // nested Any or Struct type, ignore the second to last EndObject call (depth_
+  // == -1)
+  if (ow_ != NULL && (!has_injected_value_message_ || depth_ >= 0)) {
+    ow_->EndObject();
+  }
+  // A negative depth_ implies that we have reached the end of Any
+  // object. Now we write out its contents.
+  if (depth_ < 0) {
+    WriteAny();
+    return false;
+  }
+  return true;
+}
+
+void ProtoStreamObjectWriter::AnyWriter::StartList(StringPiece name) {
+  ++depth_;
+  // We expect ow_ to be present as this call only makes sense inside an Any.
+  if (ow_ == NULL) {
+    if (!invalid_) {
+      parent_->InvalidValue("Any",
+                            StrCat("Missing or invalid @type for any field in ",
+                                   parent_->master_type_.name()));
+      invalid_ = true;
+    }
+  } else {
+    ow_->StartList(name);
+  }
+}
+
+void ProtoStreamObjectWriter::AnyWriter::EndList() {
+  --depth_;
+  if (depth_ < 0) {
+    GOOGLE_LOG(DFATAL) << "Mismatched EndList found, should not be possible";
+    depth_ = 0;
+  }
+  // We don't write an error on the close, only on the open
+  if (ow_ != NULL) {
+    ow_->EndList();
+  }
+}
+
+void ProtoStreamObjectWriter::AnyWriter::RenderDataPiece(
+    StringPiece name, const DataPiece& value) {
+  // Start an Any only at depth_ 0. Other RenderDataPiece calls with "@type"
+  // should go to the contained ow_ as they indicate nested Anys.
+  if (depth_ == 0 && ow_ == NULL && name == "@type") {
+    StartAny(value);
+  } else if (ow_ == NULL) {
+    if (!invalid_) {
+      parent_->InvalidValue("Any",
+                            StrCat("Missing or invalid @type for any field in ",
+                                   parent_->master_type_.name()));
+      invalid_ = true;
+    }
+  } else {
+    // Check to see if the data needs to be rendered with well-known-type
+    // renderer.
+    const TypeRenderer* type_renderer =
+        FindTypeRenderer(GetFullTypeWithUrl(ow_->master_type_.name()));
+    if (type_renderer) {
+      Status status = (*type_renderer)(ow_.get(), value);
+      if (!status.ok()) ow_->InvalidValue("Any", status.error_message());
+    } else {
+      ow_->RenderDataPiece(name, value);
+    }
+  }
+}
+
+void ProtoStreamObjectWriter::AnyWriter::StartAny(const DataPiece& value) {
+  // Figure out the type url. This is a copy-paste from WriteString but we also
+  // need the value, so we can't just call through to that.
+  if (value.type() == DataPiece::TYPE_STRING) {
+    type_url_ = value.str().ToString();
+  } else {
+    StatusOr<string> s = value.ToString();
+    if (!s.ok()) {
+      parent_->InvalidValue("String", s.status().error_message());
+      invalid_ = true;
+      return;
+    }
+    type_url_ = s.ValueOrDie();
+  }
+  // Resolve the type url, and report an error if we failed to resolve it.
+  StatusOr<const google::protobuf::Type*> resolved_type =
+      parent_->typeinfo()->ResolveTypeUrl(type_url_);
+  if (!resolved_type.ok()) {
+    parent_->InvalidValue("Any", resolved_type.status().error_message());
+    invalid_ = true;
+    return;
+  }
+  // At this point, type is never null.
+  const google::protobuf::Type* type = resolved_type.ValueOrDie();
+
+  // If this is the case of an Any in an Any or Struct in an Any, we need to
+  // expect a StartObject call with "value" while we're at depth_ 0, which we
+  // should ignore (not propagate to our nested object writer). We also need to
+  // ignore the second-to-last EndObject call, and not propagate that either.
+  if (type->name() == kAnyType || type->name() == kStructType) {
+    has_injected_value_message_ = true;
+  }
+
+  // Create our object writer and initialize it with the first StartObject
+  // call.
+  ow_.reset(new ProtoStreamObjectWriter(parent_->typeinfo(), *type, &output_,
+                                        parent_->listener()));
+  ow_->StartObject("");
+}
+
+void ProtoStreamObjectWriter::AnyWriter::WriteAny() {
+  if (ow_ == NULL) {
+    // If we had no object writer, we never got any content, so just return
+    // immediately, which is equivalent to writing an empty Any.
+    return;
+  }
+  // Render the type_url and value fields directly to the stream.
+  // type_url has tag 1 and value has tag 2.
+  WireFormatLite::WriteString(1, type_url_, parent_->stream());
+  if (!data_.empty()) {
+    WireFormatLite::WriteBytes(2, data_, parent_->stream());
+  }
+}
+
+ProtoStreamObjectWriter::Item::Item(ProtoStreamObjectWriter* enclosing,
+                                    ItemType item_type, bool is_placeholder,
+                                    bool is_list)
+    : BaseElement(NULL),
+      ow_(enclosing),
+      any_(),
+      item_type_(item_type),
+      is_placeholder_(is_placeholder),
+      is_list_(is_list) {
+  if (item_type_ == ANY) {
+    any_.reset(new AnyWriter(ow_));
+  }
+}
+
+ProtoStreamObjectWriter::Item::Item(ProtoStreamObjectWriter::Item* parent,
+                                    ItemType item_type, bool is_placeholder,
+                                    bool is_list)
+    : BaseElement(parent),
+      ow_(this->parent()->ow_),
+      any_(),
+      item_type_(item_type),
+      is_placeholder_(is_placeholder),
+      is_list_(is_list) {
+  if (item_type == ANY) {
+    any_.reset(new AnyWriter(ow_));
+  }
+}
+
+bool ProtoStreamObjectWriter::Item::InsertMapKeyIfNotPresent(
+    StringPiece map_key) {
+  return InsertIfNotPresent(&map_keys_, map_key.ToString());
+}
+
+ProtoStreamObjectWriter* ProtoStreamObjectWriter::StartObject(
+    StringPiece name) {
+  if (invalid_depth() > 0) {
+    IncrementInvalidDepth();
+    return this;
+  }
+
+  // Starting the root message. Create the root Item and return.
+  // ANY message type does not need special handling, just set the ItemType
+  // to ANY.
+  if (current_ == NULL) {
+    ProtoWriter::StartObject(name);
+    current_.reset(new Item(
+        this, master_type_.name() == kAnyType ? Item::ANY : Item::MESSAGE,
+        false, false));
+
+    // If master type is a special type that needs extra values to be written to
+    // stream, we write those values.
+    if (master_type_.name() == kStructType) {
+      // Struct has a map<string, Value> field called "fields".
+      // https://github.com/google/protobuf/blob/master/src/google/protobuf/struct.proto
+      // "fields": [
+      Push("fields", Item::MAP, true, true);
+      return this;
+    }
+
+    if (master_type_.name() == kStructValueType) {
+      // We got a StartObject call with google.protobuf.Value field. The only
+      // object within that type is a struct type. So start a struct.
+      //
+      // The struct field in Value type is named "struct_value"
+      // https://github.com/google/protobuf/blob/master/src/google/protobuf/struct.proto
+      // Also start the map field "fields" within the struct.
+      // "struct_value": {
+      //   "fields": [
+      Push("struct_value", Item::MESSAGE, true, false);
+      Push("fields", Item::MAP, true, true);
+      return this;
+    }
+
+    if (master_type_.name() == kStructListValueType) {
+      InvalidValue(kStructListValueType,
+                   "Cannot start root message with ListValue.");
+    }
+
+    return this;
+  }
+
+  // Send all ANY events to AnyWriter.
+  if (current_->IsAny()) {
+    current_->any()->StartObject(name);
+    return this;
+  }
+
+  // If we are within a map, we render name as keys and send StartObject to the
+  // value field.
+  if (current_->IsMap()) {
+    if (!ValidMapKey(name)) {
+      IncrementInvalidDepth();
+      return this;
+    }
+
+    // Map is a repeated field of message type with a "key" and a "value" field.
+    // https://developers.google.com/protocol-buffers/docs/proto3?hl=en#maps
+    // message MapFieldEntry {
+    //   key_type key = 1;
+    //   value_type value = 2;
+    // }
+    //
+    // repeated MapFieldEntry map_field = N;
+    //
+    // That means, we render the following element within a list (hence no
+    // name):
+    // { "key": "<name>", "value": {
+    Push("", Item::MESSAGE, false, false);
+    ProtoWriter::RenderDataPiece("key", DataPiece(name));
+    Push("value", Item::MESSAGE, true, false);
+
+    // Make sure we are valid so far after starting map fields.
+    if (invalid_depth() > 0) return this;
+
+    // If top of stack is g.p.Struct type, start the struct the map field within
+    // it.
+    if (element() != NULL && IsStruct(*element()->parent_field())) {
+      // Render "fields": [
+      Push("fields", Item::MAP, true, true);
+      return this;
+    }
+
+    // If top of stack is g.p.Value type, start the Struct within it.
+    if (element() != NULL && IsStructValue(*element()->parent_field())) {
+      // Render
+      // "struct_value": {
+      //   "fields": [
+      Push("struct_value", Item::MESSAGE, true, false);
+      Push("fields", Item::MAP, true, true);
+    }
+    return this;
+  }
+
+  const google::protobuf::Field* field = BeginNamed(name, false);
+  if (field == NULL) return this;
+
+  if (IsStruct(*field)) {
+    // Start a struct object.
+    // Render
+    // "<name>": {
+    //   "fields": {
+    Push(name, Item::MESSAGE, false, false);
+    Push("fields", Item::MAP, true, true);
+    return this;
+  }
+
+  if (IsStructValue(*field)) {
+    // We got a StartObject call with google.protobuf.Value field.  The only
+    // object within that type is a struct type. So start a struct.
+    // Render
+    // "<name>": {
+    //   "struct_value": {
+    //     "fields": {
+    Push(name, Item::MESSAGE, false, false);
+    Push("struct_value", Item::MESSAGE, true, false);
+    Push("fields", Item::MAP, true, true);
+    return this;
+  }
+
+  if (IsMap(*field)) {
+    // Begin a map. A map is triggered by a StartObject() call if the current
+    // field has a map type.
+    // A map type is always repeated, hence set is_list to true.
+    // Render
+    // "<name>": [
+    Push(name, Item::MAP, false, true);
+    return this;
+  }
+
+  // A regular message type. Pass it directly to ProtoWriter.
+  // Render
+  // "<name>": {
+  Push(name, IsAny(*field) ? Item::ANY : Item::MESSAGE, false, false);
+  return this;
+}
+
+ProtoStreamObjectWriter* ProtoStreamObjectWriter::EndObject() {
+  if (invalid_depth() > 0) {
+    DecrementInvalidDepth();
+    return this;
+  }
+
+  if (current_ == NULL) return this;
+
+  if (current_->IsAny()) {
+    if (current_->any()->EndObject()) return this;
+  }
+
+  Pop();
+
+  return this;
+}
+
+ProtoStreamObjectWriter* ProtoStreamObjectWriter::StartList(StringPiece name) {
+  if (invalid_depth() > 0) {
+    IncrementInvalidDepth();
+    return this;
+  }
+
+  // Since we cannot have a top-level repeated item in protobuf, the only way
+  // this is valid is if we start a special type google.protobuf.ListValue or
+  // google.protobuf.Value.
+  if (current_ == NULL) {
+    if (!name.empty()) {
+      InvalidName(name, "Root element should not be named.");
+      IncrementInvalidDepth();
+      return this;
+    }
+
+    // If master type is a special type that needs extra values to be written to
+    // stream, we write those values.
+    if (master_type_.name() == kStructValueType) {
+      // We got a StartList with google.protobuf.Value master type. This means
+      // we have to start the "list_value" within google.protobuf.Value.
+      //
+      // See
+      // https://github.com/google/protobuf/blob/master/src/google/protobuf/struct.proto
+      //
+      // Render
+      // "<name>": {
+      //   "list_value": {
+      //     "values": [  // Start this list.
+      ProtoWriter::StartObject(name);
+      current_.reset(new Item(this, Item::MESSAGE, false, false));
+      Push("list_value", Item::MESSAGE, true, false);
+      Push("values", Item::MESSAGE, true, true);
+      return this;
+    }
+
+    if (master_type_.name() == kStructListValueType) {
+      // We got a StartList with google.protobuf.ListValue master type. This
+      // means we have to start the "values" within google.protobuf.ListValue.
+      //
+      // Render
+      // "<name>": {
+      //   "values": [  // Start this list.
+      ProtoWriter::StartObject(name);
+      current_.reset(new Item(this, Item::MESSAGE, false, false));
+      Push("values", Item::MESSAGE, true, true);
+      return this;
+    }
+
+    // Send the event to ProtoWriter so proper errors can be reported.
+    //
+    // Render a regular list:
+    // "<name>": [
+    ProtoWriter::StartList(name);
+    current_.reset(new Item(this, Item::MESSAGE, false, true));
+    return this;
+  }
+
+  if (current_->IsAny()) {
+    current_->any()->StartList(name);
+    return this;
+  }
+
+  // If the top of stack is a map, we are starting a list value within a map.
+  // Since map does not allow repeated values, this can only happen when the map
+  // value is of a special type that renders a list in JSON.  These can be one
+  // of 3 cases:
+  // i. We are rendering a list value within google.protobuf.Struct
+  // ii. We are rendering a list value within google.protobuf.Value
+  // iii. We are rendering a list value with type google.protobuf.ListValue.
+  if (current_->IsMap()) {
+    if (!ValidMapKey(name)) {
+      IncrementInvalidDepth();
+      return this;
+    }
+
+    // Start the repeated map entry object.
+    // Render
+    // { "key": "<name>", "value": {
+    Push("", Item::MESSAGE, false, false);
+    ProtoWriter::RenderDataPiece("key", DataPiece(name));
+    Push("value", Item::MESSAGE, true, false);
+
+    // Make sure we are valid after pushing all above items.
+    if (invalid_depth() > 0) return this;
+
+    // case i and ii above. Start "list_value" field within g.p.Value
+    if (element() != NULL && element()->parent_field() != NULL) {
+      // Render
+      // "list_value": {
+      //   "values": [  // Start this list
+      if (IsStructValue(*element()->parent_field())) {
+        Push("list_value", Item::MESSAGE, true, false);
+        Push("values", Item::MESSAGE, true, true);
+        return this;
+      }
+
+      // Render
+      // "values": [
+      if (IsStructListValue(*element()->parent_field())) {
+        // case iii above. Bind directly to g.p.ListValue
+        Push("values", Item::MESSAGE, true, true);
+        return this;
+      }
+    }
+
+    // Report an error.
+    InvalidValue("Map", StrCat("Cannot have repeated items ('", name,
+                               "') within a map."));
+    return this;
+  }
+
+  // When name is empty and stack is not empty, we are rendering an item within
+  // a list.
+  if (name.empty()) {
+    if (element() != NULL && element()->parent_field() != NULL) {
+      if (IsStructValue(*element()->parent_field())) {
+        // Since it is g.p.Value, we bind directly to the list_value.
+        // Render
+        // {  // g.p.Value item within the list
+        //   "list_value": {
+        //     "values": [
+        Push("", Item::MESSAGE, false, false);
+        Push("list_value", Item::MESSAGE, true, false);
+        Push("values", Item::MESSAGE, true, true);
+        return this;
+      }
+
+      if (IsStructListValue(*element()->parent_field())) {
+        // Since it is g.p.ListValue, we bind to it directly.
+        // Render
+        // {  // g.p.ListValue item within the list
+        //   "values": [
+        Push("", Item::MESSAGE, false, false);
+        Push("values", Item::MESSAGE, true, true);
+        return this;
+      }
+    }
+
+    // Pass the event to underlying ProtoWriter.
+    Push(name, Item::MESSAGE, false, true);
+    return this;
+  }
+
+  // name is not empty
+  const google::protobuf::Field* field = Lookup(name);
+  if (field == NULL) {
+    IncrementInvalidDepth();
+    return this;
+  }
+
+  if (IsStructValue(*field)) {
+    // If g.p.Value is repeated, start that list. Otherwise, start the
+    // "list_value" within it.
+    if (IsRepeated(*field)) {
+      // Render it just like a regular repeated field.
+      // "<name>": [
+      Push(name, Item::MESSAGE, false, true);
+      return this;
+    }
+
+    // Start the "list_value" field.
+    // Render
+    // "<name>": {
+    //   "list_value": {
+    //     "values": [
+    Push(name, Item::MESSAGE, false, false);
+    Push("list_value", Item::MESSAGE, true, false);
+    Push("values", Item::MESSAGE, true, true);
+    return this;
+  }
+
+  if (IsStructListValue(*field)) {
+    // If g.p.ListValue is repeated, start that list. Otherwise, start the
+    // "values" within it.
+    if (IsRepeated(*field)) {
+      // Render it just like a regular repeated field.
+      // "<name>": [
+      Push(name, Item::MESSAGE, false, true);
+      return this;
+    }
+
+    // Start the "values" field within g.p.ListValue.
+    // Render
+    // "<name>": {
+    //   "values": [
+    Push(name, Item::MESSAGE, false, false);
+    Push("values", Item::MESSAGE, true, true);
+    return this;
+  }
+
+  // If we are here, the field should be repeated. Report an error otherwise.
+  if (!IsRepeated(*field)) {
+    IncrementInvalidDepth();
+    InvalidName(name, "Proto field is not repeating, cannot start list.");
+    return this;
+  }
+
+  if (IsMap(*field)) {
+    InvalidValue("Map",
+                 StrCat("Cannot bind a list to map for field '", name, "'."));
+    IncrementInvalidDepth();
+    return this;
+  }
+
+  // Pass the event to ProtoWriter.
+  // Render
+  // "<name>": [
+  Push(name, Item::MESSAGE, false, true);
+  return this;
+}
+
+ProtoStreamObjectWriter* ProtoStreamObjectWriter::EndList() {
+  if (invalid_depth() > 0) {
+    DecrementInvalidDepth();
+    return this;
+  }
+
+  if (current_ == NULL) return this;
+
+  if (current_->IsAny()) {
+    current_->any()->EndList();
+    return this;
+  }
+
+  Pop();
+  return this;
+}
+
+Status ProtoStreamObjectWriter::RenderStructValue(ProtoStreamObjectWriter* ow,
+                                                  const DataPiece& data) {
+  string struct_field_name;
+  switch (data.type()) {
+    // Our JSON parser parses numbers as either int64, uint64, or double.
+    case DataPiece::TYPE_INT64:
+    case DataPiece::TYPE_UINT64:
+    case DataPiece::TYPE_DOUBLE: {
+      struct_field_name = "number_value";
+      break;
+    }
+    case DataPiece::TYPE_STRING: {
+      struct_field_name = "string_value";
+      break;
+    }
+    case DataPiece::TYPE_BOOL: {
+      struct_field_name = "bool_value";
+      break;
+    }
+    case DataPiece::TYPE_NULL: {
+      struct_field_name = "null_value";
+      break;
+    }
+    default: {
+      return Status(INVALID_ARGUMENT,
+                    "Invalid struct data type. Only number, string, boolean or "
+                    "null values are supported.");
+    }
+  }
+  ow->ProtoWriter::RenderDataPiece(struct_field_name, data);
+  return Status::OK;
+}
+
+Status ProtoStreamObjectWriter::RenderTimestamp(ProtoStreamObjectWriter* ow,
+                                                const DataPiece& data) {
+  if (data.type() != DataPiece::TYPE_STRING) {
+    return Status(INVALID_ARGUMENT,
+                  StrCat("Invalid data type for timestamp, value is ",
+                         data.ValueAsStringOrDefault("")));
+  }
+
+  StringPiece value(data.str());
+
+  int64 seconds;
+  int32 nanos;
+  if (!::google::protobuf::internal::ParseTime(value.ToString(), &seconds,
+                                               &nanos)) {
+    return Status(INVALID_ARGUMENT, StrCat("Invalid time format: ", value));
+  }
+
+
+  ow->ProtoWriter::RenderDataPiece("seconds", DataPiece(seconds));
+  ow->ProtoWriter::RenderDataPiece("nanos", DataPiece(nanos));
+  return Status::OK;
+}
+
+static inline util::Status RenderOneFieldPath(ProtoStreamObjectWriter* ow,
+                                                StringPiece path) {
+  ow->ProtoWriter::RenderDataPiece(
+      "paths", DataPiece(ConvertFieldMaskPath(path, &ToSnakeCase)));
+  return Status::OK;
+}
+
+Status ProtoStreamObjectWriter::RenderFieldMask(ProtoStreamObjectWriter* ow,
+                                                const DataPiece& data) {
+  if (data.type() != DataPiece::TYPE_STRING) {
+    return Status(INVALID_ARGUMENT,
+                  StrCat("Invalid data type for field mask, value is ",
+                         data.ValueAsStringOrDefault("")));
+  }
+
+// TODO(tsun): figure out how to do proto descriptor based snake case
+// conversions as much as possible. Because ToSnakeCase sometimes returns the
+// wrong value.
+  google::protobuf::scoped_ptr<ResultCallback1<util::Status, StringPiece> > callback(
+      google::protobuf::internal::NewPermanentCallback(&RenderOneFieldPath, ow));
+  return DecodeCompactFieldMaskPaths(data.str(), callback.get());
+}
+
+Status ProtoStreamObjectWriter::RenderDuration(ProtoStreamObjectWriter* ow,
+                                               const DataPiece& data) {
+  if (data.type() != DataPiece::TYPE_STRING) {
+    return Status(INVALID_ARGUMENT,
+                  StrCat("Invalid data type for duration, value is ",
+                         data.ValueAsStringOrDefault("")));
+  }
+
+  StringPiece value(data.str());
+
+  if (!value.ends_with("s")) {
+    return Status(INVALID_ARGUMENT,
+                  "Illegal duration format; duration must end with 's'");
+  }
+  value = value.substr(0, value.size() - 1);
+  int sign = 1;
+  if (value.starts_with("-")) {
+    sign = -1;
+    value = value.substr(1);
+  }
+
+  StringPiece s_secs, s_nanos;
+  SplitSecondsAndNanos(value, &s_secs, &s_nanos);
+  uint64 unsigned_seconds;
+  if (!safe_strtou64(s_secs, &unsigned_seconds)) {
+    return Status(INVALID_ARGUMENT,
+                  "Invalid duration format, failed to parse seconds");
+  }
+
+  int32 nanos = 0;
+  Status nanos_status = GetNanosFromStringPiece(
+      s_nanos, "Invalid duration format, failed to parse nano seconds",
+      "Duration value exceeds limits", &nanos);
+  if (!nanos_status.ok()) {
+    return nanos_status;
+  }
+  nanos = sign * nanos;
+
+  int64 seconds = sign * unsigned_seconds;
+  if (seconds > kMaxSeconds || seconds < kMinSeconds ||
+      nanos <= -kNanosPerSecond || nanos >= kNanosPerSecond) {
+    return Status(INVALID_ARGUMENT, "Duration value exceeds limits");
+  }
+
+  ow->ProtoWriter::RenderDataPiece("seconds", DataPiece(seconds));
+  ow->ProtoWriter::RenderDataPiece("nanos", DataPiece(nanos));
+  return Status::OK;
+}
+
+Status ProtoStreamObjectWriter::RenderWrapperType(ProtoStreamObjectWriter* ow,
+                                                  const DataPiece& data) {
+  ow->ProtoWriter::RenderDataPiece("value", data);
+  return Status::OK;
+}
+
+ProtoStreamObjectWriter* ProtoStreamObjectWriter::RenderDataPiece(
+    StringPiece name, const DataPiece& data) {
+  Status status;
+  if (invalid_depth() > 0) return this;
+
+  if (current_ == NULL) {
+    const TypeRenderer* type_renderer =
+        FindTypeRenderer(GetFullTypeWithUrl(master_type_.name()));
+    if (type_renderer == NULL) {
+      InvalidName(name, "Root element must be a message.");
+      return this;
+    }
+    // Render the special type.
+    // "<name>": {
+    //   ... Render special type ...
+    // }
+    ProtoWriter::StartObject(name);
+    status = (*type_renderer)(this, data);
+    if (!status.ok()) {
+      InvalidValue(master_type_.name(),
+                   StrCat("Field '", name, "', ", status.error_message()));
+    }
+    ProtoWriter::EndObject();
+    return this;
+  }
+
+  if (current_->IsAny()) {
+    current_->any()->RenderDataPiece(name, data);
+    return this;
+  }
+
+  const google::protobuf::Field* field = NULL;
+  if (current_->IsMap()) {
+    if (!ValidMapKey(name)) return this;
+
+    // Render an item in repeated map list.
+    // { "key": "<name>", "value":
+    Push("", Item::MESSAGE, false, false);
+    ProtoWriter::RenderDataPiece("key", DataPiece(name));
+    field = Lookup("value");
+    if (field == NULL) {
+      GOOGLE_LOG(DFATAL) << "Map does not have a value field.";
+      return this;
+    }
+
+    const TypeRenderer* type_renderer = FindTypeRenderer(field->type_url());
+    if (type_renderer != NULL) {
+      // Map's value type is a special type. Render it like a message:
+      // "value": {
+      //   ... Render special type ...
+      // }
+      Push("value", Item::MESSAGE, true, false);
+      status = (*type_renderer)(this, data);
+      if (!status.ok()) {
+        InvalidValue(field->type_url(),
+                     StrCat("Field '", name, "', ", status.error_message()));
+      }
+      Pop();
+      return this;
+    }
+
+    // If we are rendering explicit null values and the backend proto field is
+    // not of the google.protobuf.NullType type, we do nothing.
+    if (data.type() == DataPiece::TYPE_NULL &&
+        field->type_url() != kStructNullValueTypeUrl) {
+      return this;
+    }
+
+    // Render the map value as a primitive type.
+    ProtoWriter::RenderDataPiece("value", data);
+    Pop();
+    return this;
+  }
+
+  field = Lookup(name);
+  if (field == NULL) return this;
+
+  // Check if the field is of special type. Render it accordingly if so.
+  const TypeRenderer* type_renderer = FindTypeRenderer(field->type_url());
+  if (type_renderer != NULL) {
+    Push(name, Item::MESSAGE, false, false);
+    status = (*type_renderer)(this, data);
+    if (!status.ok()) {
+      InvalidValue(field->type_url(),
+                   StrCat("Field '", name, "', ", status.error_message()));
+    }
+    Pop();
+    return this;
+  }
+
+  // If we are rendering explicit null values and the backend proto field is
+  // not of the google.protobuf.NullType type, we do nothing.
+  if (data.type() == DataPiece::TYPE_NULL &&
+      field->type_url() != kStructNullValueTypeUrl) {
+    return this;
+  }
+
+  ProtoWriter::RenderDataPiece(name, data);
+  return this;
+}
+
+// Map of functions that are responsible for rendering well known type
+// represented by the key.
+hash_map<string, ProtoStreamObjectWriter::TypeRenderer>*
+    ProtoStreamObjectWriter::renderers_ = NULL;
+GOOGLE_PROTOBUF_DECLARE_ONCE(writer_renderers_init_);
+
+void ProtoStreamObjectWriter::InitRendererMap() {
+  renderers_ = new hash_map<string, ProtoStreamObjectWriter::TypeRenderer>();
+  (*renderers_)["type.googleapis.com/google.protobuf.Timestamp"] =
+      &ProtoStreamObjectWriter::RenderTimestamp;
+  (*renderers_)["type.googleapis.com/google.protobuf.Duration"] =
+      &ProtoStreamObjectWriter::RenderDuration;
+  (*renderers_)["type.googleapis.com/google.protobuf.FieldMask"] =
+      &ProtoStreamObjectWriter::RenderFieldMask;
+  (*renderers_)["type.googleapis.com/google.protobuf.Double"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.Float"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.Int64"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.UInt64"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.Int32"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.UInt32"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.Bool"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.String"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.Bytes"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.DoubleValue"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.FloatValue"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.Int64Value"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.UInt64Value"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.Int32Value"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.UInt32Value"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.BoolValue"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.StringValue"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.BytesValue"] =
+      &ProtoStreamObjectWriter::RenderWrapperType;
+  (*renderers_)["type.googleapis.com/google.protobuf.Value"] =
+      &ProtoStreamObjectWriter::RenderStructValue;
+  ::google::protobuf::internal::OnShutdown(&DeleteRendererMap);
+}
+
+void ProtoStreamObjectWriter::DeleteRendererMap() {
+  delete ProtoStreamObjectWriter::renderers_;
+  renderers_ = NULL;
+}
+
+ProtoStreamObjectWriter::TypeRenderer*
+ProtoStreamObjectWriter::FindTypeRenderer(const string& type_url) {
+  ::google::protobuf::GoogleOnceInit(&writer_renderers_init_, &InitRendererMap);
+  return FindOrNull(*renderers_, type_url);
+}
+
+bool ProtoStreamObjectWriter::ValidMapKey(StringPiece unnormalized_name) {
+  if (current_ == NULL) return true;
+
+  if (!current_->InsertMapKeyIfNotPresent(unnormalized_name)) {
+    listener()->InvalidName(
+        location(), unnormalized_name,
+        StrCat("Repeated map key: '", unnormalized_name, "' is already set."));
+    return false;
+  }
+
+  return true;
+}
+
+void ProtoStreamObjectWriter::Push(StringPiece name, Item::ItemType item_type,
+                                   bool is_placeholder, bool is_list) {
+  is_list ? ProtoWriter::StartList(name) : ProtoWriter::StartObject(name);
+
+  // invalid_depth == 0 means it is a successful StartObject or StartList.
+  if (invalid_depth() == 0)
+    current_.reset(
+        new Item(current_.release(), item_type, is_placeholder, is_list));
+}
+
+void ProtoStreamObjectWriter::Pop() {
+  // Pop all placeholder items sending StartObject or StartList events to
+  // ProtoWriter according to is_list value.
+  while (current_ != NULL && current_->is_placeholder()) {
+    PopOneElement();
+  }
+  if (current_ != NULL) {
+    PopOneElement();
+  }
+}
+
+void ProtoStreamObjectWriter::PopOneElement() {
+  current_->is_list() ? ProtoWriter::EndList() : ProtoWriter::EndObject();
+  current_.reset(current_->pop<Item>());
+}
+
+bool ProtoStreamObjectWriter::IsMap(const google::protobuf::Field& field) {
+  if (field.type_url().empty() ||
+      field.kind() != google::protobuf::Field_Kind_TYPE_MESSAGE ||
+      field.cardinality() !=
+          google::protobuf::Field_Cardinality_CARDINALITY_REPEATED) {
+    return false;
+  }
+  const google::protobuf::Type* field_type =
+      typeinfo()->GetTypeByTypeUrl(field.type_url());
+
+  // TODO(xiaofeng): Unify option names.
+  return GetBoolOptionOrDefault(field_type->options(),
+                                "google.protobuf.MessageOptions.map_entry", false) ||
+         GetBoolOptionOrDefault(field_type->options(), "map_entry", false);
+}
+
+bool ProtoStreamObjectWriter::IsAny(const google::protobuf::Field& field) {
+  return GetTypeWithoutUrl(field.type_url()) == kAnyType;
+}
+
+bool ProtoStreamObjectWriter::IsStruct(const google::protobuf::Field& field) {
+  return GetTypeWithoutUrl(field.type_url()) == kStructType;
+}
+
+bool ProtoStreamObjectWriter::IsStructValue(
+    const google::protobuf::Field& field) {
+  return GetTypeWithoutUrl(field.type_url()) == kStructValueType;
+}
+
+bool ProtoStreamObjectWriter::IsStructListValue(
+    const google::protobuf::Field& field) {
+  return GetTypeWithoutUrl(field.type_url()) == kStructListValueType;
+}
+
+}  // namespace converter
+}  // namespace util
+}  // namespace protobuf
+}  // namespace google