Introduce mojo_base.mojom.BigString

BigString uses BigBuffer internally to accomodate
large strings.

It maps to std::string and WTF::String and internally
converts data to UTF8 similary to regular string.

Bug: 776009
Change-Id: I05547f6f55f0a20dafd6a3d99e26b5cc2cbe2eed
Reviewed-on: https://chromium-review.googlesource.com/891980
Commit-Queue: Dmitry Gozman <dgozman@chromium.org>
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Ken Rockot <rockot@chromium.org>
Cr-Commit-Position: refs/heads/master@{#533182}

content/public/common/BUILD.gn

@@ -261,6 +261,7 @@ jumbo_source_set("common_sources") {
     "//ipc",
     "//media/capture:capture_base",
     "//mojo/edk/system",
+    "//mojo/public/cpp/base:mojom_traits",
     "//mojo/public/cpp/bindings",
     "//net",
     "//services/network/public/cpp",

mojo/public/cpp/base/BUILD.gn

@@ -41,15 +41,29 @@ component("shared_typemap_traits") {
   ]
 }
 
+source_set("mojom_traits") {
+  sources = [
+    "big_string_mojom_traits.cc",
+    "big_string_mojom_traits.h",
+  ]
+  deps = [
+    ":base",
+    ":shared_typemap_traits",
+    "//mojo/public/mojom/base",
+  ]
+}
+
 source_set("tests") {
   testonly = true
 
   sources = [
     "big_buffer_unittest.cc",
+    "big_string_unittest.cc",
   ]
 
   public_deps = [
     ":base",
+    ":mojom_traits",
     ":shared_typemap_traits",
     "//base",
     "//mojo/public/cpp/test_support:test_utils",

mojo/public/cpp/base/OWNERS

 per-file *.typemap=set noparent
 per-file *.typemap=file://ipc/SECURITY_OWNERS
+per-file *_mojom_traits*.*=set noparent
+per-file *_mojom_traits*.*=file://ipc/SECURITY_OWNERS
 per-file *_struct_traits*.*=set noparent
 per-file *_struct_traits*.*=file://ipc/SECURITY_OWNERS

mojo/public/cpp/base/big_string.typemap

+# Copyright 2018 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+mojom = "//mojo/public/mojom/base/big_string.mojom"
+public_headers = []
+traits_headers = [ "//mojo/public/cpp/base/big_string_mojom_traits.h" ]
+public_deps = [
+  "//mojo/public/cpp/base",
+  "//mojo/public/cpp/base:shared_typemap_traits",
+]
+type_mappings = [ "mojo_base.mojom.BigString=std::string" ]

mojo/public/cpp/base/big_string_mojom_traits.cc

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "mojo/public/cpp/base/big_string_mojom_traits.h"
+
+#include "mojo/public/cpp/base/big_buffer_struct_traits.h"
+
+namespace mojo {
+
+// static
+mojo_base::BigBuffer StructTraits<mojo_base::mojom::BigStringDataView,
+                                  std::string>::data(const std::string& str) {
+  const auto* bytes = reinterpret_cast<const uint8_t*>(str.data());
+  return mojo_base::BigBuffer(
+      base::make_span(bytes, str.size() * sizeof(char)));
+}
+
+// static
+bool StructTraits<mojo_base::mojom::BigStringDataView, std::string>::Read(
+    mojo_base::mojom::BigStringDataView data,
+    std::string* out) {
+  mojo_base::BigBuffer buffer;
+  if (!data.ReadData(&buffer))
+    return false;
+  if (buffer.size() % sizeof(char))
+    return false;
+  *out = std::string(reinterpret_cast<const char*>(buffer.data()),
+                     buffer.size() / sizeof(char));
+  return true;
+}
+
+}  // namespace mojo

mojo/public/cpp/base/big_string_mojom_traits.h

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MOJO_PUBLIC_CPP_BASE_BIG_STRING_MOJOM_TRAITS_H_
+#define MOJO_PUBLIC_CPP_BASE_BIG_STRING_MOJOM_TRAITS_H_
+
+#include <string>
+
+#include "mojo/public/cpp/base/big_buffer.h"
+#include "mojo/public/cpp/bindings/struct_traits.h"
+#include "mojo/public/mojom/base/big_string.mojom-shared.h"
+
+namespace mojo {
+
+template <>
+struct StructTraits<mojo_base::mojom::BigStringDataView, std::string> {
+  static mojo_base::BigBuffer data(const std::string& str);
+
+  static bool Read(mojo_base::mojom::BigStringDataView data, std::string* out);
+};
+
+}  // namespace mojo
+
+#endif  // MOJO_PUBLIC_CPP_BASE_BIG_STRING_MOJOM_TRAITS_H_

mojo/public/cpp/base/big_string_unittest.cc

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include <string>
+
+#include "base/rand_util.h"
+#include "mojo/public/cpp/base/big_buffer_struct_traits.h"
+#include "mojo/public/cpp/base/big_string_mojom_traits.h"
+#include "mojo/public/cpp/test_support/test_utils.h"
+#include "mojo/public/mojom/base/big_string.mojom.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace mojo_base {
+namespace big_string_unittest {
+
+TEST(BigStringTest, Empty) {
+  std::string in;
+  std::string out;
+  ASSERT_TRUE(mojo::test::SerializeAndDeserialize<mojom::BigString>(&in, &out));
+  EXPECT_EQ(in, out);
+}
+
+TEST(BigStringTest, Short) {
+  std::string in("hello world");
+  std::string out;
+  ASSERT_TRUE(mojo::test::SerializeAndDeserialize<mojom::BigString>(&in, &out));
+  EXPECT_EQ(in, out);
+}
+
+TEST(BigStringTest, Long) {
+  constexpr size_t kLargeStringSize = 1024 * 1024;
+
+  std::string in(kLargeStringSize, 0);
+  base::RandBytes(&in[0], kLargeStringSize);
+
+  std::string out;
+  ASSERT_TRUE(mojo::test::SerializeAndDeserialize<mojom::BigString>(&in, &out));
+  EXPECT_EQ(in, out);
+}
+
+}  // namespace big_string_unittest
+}  // namespace mojo_base

mojo/public/cpp/base/typemaps.gni

@@ -2,4 +2,7 @@
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
-typemaps = [ "//mojo/public/cpp/base/big_buffer.typemap" ]
+typemaps = [
+  "//mojo/public/cpp/base/big_buffer.typemap",
+  "//mojo/public/cpp/base/big_string.typemap",
+]

mojo/public/mojom/base/BUILD.gn

@@ -7,6 +7,7 @@ import("//mojo/public/tools/bindings/mojom.gni")
 mojom_component("base") {
   sources = [
     "big_buffer.mojom",
+    "big_string.mojom",
   ]
 
   output_prefix = "mojo_base_mojom"

mojo/public/mojom/base/big_string.mojom

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+module mojo_base.mojom;
+
+import "mojo/public/mojom/base/big_buffer.mojom";
+
+// Corresponds to |std::string| in <string>.
+// Corresponds to |WTF::String| in
+// third_party/WebKit/Source/platform/wtf/text/WTFString.h.
+// This type should be used in place of string whenever the contents of the
+// string may realistically exceed 64 kB in size. This string is safe to store
+// an arbitrarily large amount of data (available memory permitting) without
+// negatively impacting IPC performance or hitting hard message size
+// boundaries.
+struct BigString {
+  mojo_base.mojom.BigBuffer data;
+};

third_party/WebKit/Source/platform/BUILD.gn

@@ -1312,6 +1312,8 @@ jumbo_component("platform") {
     "mhtml/MHTMLArchive.h",
     "mhtml/MHTMLParser.cpp",
     "mhtml/MHTMLParser.h",
+    "mojo/BigStringMojomTraits.cpp",
+    "mojo/BigStringMojomTraits.h",
     "mojo/BluetoothStructTraits.cpp",
     "mojo/BluetoothStructTraits.h",
     "mojo/CommonCustomTypesStructTraits.cpp",
@@ -1909,6 +1911,7 @@ jumbo_source_set("blink_platform_unittests_sources") {
     "json/JSONValuesTest.cpp",
     "mac/GraphicsContextCanvasTest.mm",
     "mac/VersionUtilMacTest.mm",
+    "mojo/BigStringMojomTraitsTest.cpp",
     "mojo/CommonCustomTypesStructTraitsTest.cpp",
     "mojo/GeometryStructTraitsTest.cpp",
     "mojo/InterfaceInvalidatorTest.cpp",

third_party/WebKit/Source/platform/mojo/BigString.typemap

+# Copyright 2018 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+mojom = "//mojo/public/mojom/base/big_string.mojom"
+public_headers = [ "//third_party/WebKit/Source/platform/wtf/text/WTFString.h" ]
+traits_headers =
+    [ "//third_party/WebKit/Source/platform/mojo/BigStringMojomTraits.h" ]
+type_mappings =
+    [ "mojo_base.mojom.BigString=WTF::String[nullable_is_same_type]" ]

third_party/WebKit/Source/platform/mojo/BigStringMojomTraits.cpp

+// Copyright 2016 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "platform/mojo/BigStringMojomTraits.h"
+
+#include <cstring>
+
+#include "base/containers/span.h"
+#include "mojo/public/cpp/base/big_buffer.h"
+#include "mojo/public/cpp/base/big_buffer_struct_traits.h"
+#include "platform/wtf/text/StringUTF8Adaptor.h"
+
+namespace mojo {
+
+// static
+mojo_base::BigBuffer StructTraits<mojo_base::mojom::BigStringDataView,
+                                  WTF::String>::data(const WTF::String& input) {
+  WTF::StringUTF8Adaptor adaptor(input);
+  return mojo_base::BigBuffer(
+      base::make_span(reinterpret_cast<const uint8_t*>(adaptor.Data()),
+                      adaptor.length() * sizeof(char)));
+}
+
+// static
+bool StructTraits<mojo_base::mojom::BigStringDataView, WTF::String>::Read(
+    mojo_base::mojom::BigStringDataView data,
+    WTF::String* out) {
+  mojo_base::BigBuffer buffer;
+  if (!data.ReadData(&buffer))
+    return false;
+  size_t size = buffer.size();
+  if (size % sizeof(char))
+    return false;
+  // An empty |mojo_base::BigBuffer| may have a null |data()| if empty.
+  if (!size) {
+    *out = g_empty_string;
+  } else {
+    *out = WTF::String::FromUTF8(reinterpret_cast<const char*>(buffer.data()),
+                                 size / sizeof(char));
+  }
+  return true;
+}
+
+}  // namespace mojo

third_party/WebKit/Source/platform/mojo/BigStringMojomTraits.h

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef BigStringMojomTraits_h
+#define BigStringMojomTraits_h
+
+#include "mojo/public/cpp/bindings/struct_traits.h"
+#include "mojo/public/mojom/base/big_string.mojom-blink.h"
+#include "platform/PlatformExport.h"
+
+namespace mojo_base {
+class BigBuffer;
+}
+
+namespace mojo {
+
+template <>
+struct PLATFORM_EXPORT
+    StructTraits<mojo_base::mojom::BigStringDataView, WTF::String> {
+  static bool IsNull(const WTF::String& input) { return input.IsNull(); }
+  static void SetToNull(WTF::String* output) { *output = WTF::String(); }
+
+  static mojo_base::BigBuffer data(const WTF::String& input);
+  static bool Read(mojo_base::mojom::BigStringDataView, WTF::String* out);
+};
+
+}  // namespace mojo
+
+#endif  // BigStringMojomTraits_h

third_party/WebKit/Source/platform/mojo/BigStringMojomTraitsTest.cpp

+// Copyright 2018 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "base/rand_util.h"
+#include "mojo/common/test_common_custom_types.mojom-blink.h"
+#include "mojo/public/cpp/base/big_buffer_struct_traits.h"
+#include "mojo/public/cpp/test_support/test_utils.h"
+#include "mojo/public/mojom/base/big_string.mojom-blink.h"
+#include "platform/wtf/text/WTFString.h"
+#include "testing/gtest/include/gtest/gtest.h"
+#include "third_party/WebKit/Source/platform/mojo/BigStringMojomTraits.h"
+#include "third_party/WebKit/Source/platform/wtf/text/WTFString.h"
+
+namespace blink {
+
+TEST(BigStringMojomTraitsTest, BigString_Null) {
+  String str;
+  String output;
+
+  ASSERT_TRUE(
+      mojo::test::SerializeAndDeserialize<mojo_base::mojom::blink::BigString>(
+          &str, &output));
+  ASSERT_EQ(str, output);
+}
+
+TEST(BigStringMojomTraitsTest, BigString_Empty) {
+  String str = String::FromUTF8("");
+  String output;
+
+  ASSERT_TRUE(
+      mojo::test::SerializeAndDeserialize<mojo_base::mojom::blink::BigString>(
+          &str, &output));
+  ASSERT_EQ(str, output);
+}
+
+TEST(BigStringMojomTraitsTest, BigString_Short) {
+  String str = String::FromUTF8("hello world");
+  ASSERT_TRUE(str.Is8Bit());
+  String output;
+
+  ASSERT_TRUE(
+      mojo::test::SerializeAndDeserialize<mojo_base::mojom::blink::BigString>(
+          &str, &output));
+  ASSERT_EQ(str, output);
+
+  // Replace the "o"s in "hello world" with "o"s with acute, so that |str| is
+  // 16-bit.
+  str = String::FromUTF8("hell\xC3\xB3 w\xC3\xB3rld");
+  ASSERT_FALSE(str.Is8Bit());
+
+  ASSERT_TRUE(
+      mojo::test::SerializeAndDeserialize<mojo_base::mojom::blink::BigString>(
+          &str, &output));
+  ASSERT_EQ(str, output);
+}
+
+TEST(BigStringMojomTraitsTest, BigString_Long) {
+  WTF::Vector<char> random_latin1_string(1024 * 1024);
+  base::RandBytes(random_latin1_string.data(), random_latin1_string.size());
+
+  String str(random_latin1_string.data(), random_latin1_string.size());
+  String output;
+
+  ASSERT_TRUE(
+      mojo::test::SerializeAndDeserialize<mojo_base::mojom::blink::BigString>(
+          &str, &output));
+  ASSERT_EQ(str, output);
+}
+
+}  // namespace blink

third_party/WebKit/Source/platform/mojo/DEPS

@@ -7,6 +7,7 @@ include_rules = [
     "+base/observer_list.h",
     "+base/strings/string16.h",
     "+mojo/public/cpp/bindings/binding.h",
+    "+mojo/common/big_string.mojom-blink.h",
     "+mojo/common/string16.mojom-blink.h",
     "+mojo/common/test_common_custom_types.mojom-blink.h",
     "+services/network/public/interfaces/fetch_api.mojom-blink.h",

third_party/WebKit/Source/platform/mojo/OWNERS

+per-file *MojomTraits*.*=set noparent
+per-file *MojomTraits*.*=file://ipc/SECURITY_OWNERS
 per-file *StructTraits*.*=set noparent
 per-file *StructTraits*.*=file://ipc/SECURITY_OWNERS
 per-file *.typemap=set noparent

third_party/WebKit/Source/platform/mojo/blink_typemaps.gni

@@ -9,6 +9,7 @@ typemaps = [
   "//third_party/WebKit/Source/core/messaging/BlinkTransferableMessage.typemap",
   "//third_party/WebKit/Source/platform/blob/SerializedBlob.typemap",
   "//third_party/WebKit/Source/platform/mojo/BigBuffer.typemap",
+  "//third_party/WebKit/Source/platform/mojo/BigString.typemap",
   "//third_party/WebKit/Source/platform/mojo/File.typemap",
   "//third_party/WebKit/Source/platform/mojo/Geometry.typemap",
   "//third_party/WebKit/Source/platform/mojo/KURL.typemap",