[base] Prepare //mojo and //ipc for string16 switch

This change prepares //mojo and //ipc for the upcoming switch of
base::string16 to std::u16string by replacing current Windows only
usages of base::string16 with std::wstring. Furthermore, it adds a
std::wstring specialization of IPC::ParamTraits.

Bug: 911896
Change-Id: If09078ba43a381f7210f89bba04a729024812d1f
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2572842
Reviewed-by: Daniel Cheng <dcheng@chromium.org>
Reviewed-by: Ken Rockot <rockot@google.com>
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Cr-Commit-Position: refs/heads/master@{#834355}

ipc/ipc_message_utils.cc

@@ -409,6 +409,23 @@ void ParamTraits<base::string16>::Log(const param_type& p, std::string* l) {
   l->append(base::UTF16ToUTF8(p));
 }
 
+#if defined(OS_WIN) && defined(BASE_STRING16_IS_STD_U16STRING)
+bool ParamTraits<std::wstring>::Read(const base::Pickle* m,
+                                     base::PickleIterator* iter,
+                                     param_type* r) {
+  base::StringPiece16 piece16;
+  if (!iter->ReadStringPiece16(&piece16))
+    return false;
+
+  *r = base::AsWString(piece16);
+  return true;
+}
+
+void ParamTraits<std::wstring>::Log(const param_type& p, std::string* l) {
+  l->append(base::WideToUTF8(p));
+}
+#endif
+
 void ParamTraits<std::vector<char>>::Write(base::Pickle* m,
                                            const param_type& p) {
   if (p.empty()) {

ipc/ipc_message_utils.h

@@ -346,6 +346,20 @@ struct ParamTraits<base::string16> {
   COMPONENT_EXPORT(IPC) static void Log(const param_type& p, std::string* l);
 };
 
+#if defined(OS_WIN) && defined(BASE_STRING16_IS_STD_U16STRING)
+template <>
+struct ParamTraits<std::wstring> {
+  typedef std::wstring param_type;
+  static void Write(base::Pickle* m, const param_type& p) {
+    m->WriteString16(base::AsStringPiece16(p));
+  }
+  static bool Read(const base::Pickle* m,
+                   base::PickleIterator* iter,
+                   param_type* r);
+  COMPONENT_EXPORT(IPC) static void Log(const param_type& p, std::string* l);
+};
+#endif
+
 template <>
 struct COMPONENT_EXPORT(IPC) ParamTraits<std::vector<char>> {
   typedef std::vector<char> param_type;

mojo/core/broker_host.cc

@@ -91,9 +91,9 @@ bool BrokerHost::SendChannel(PlatformHandle handle) {
 
 #if defined(OS_WIN)
 
-void BrokerHost::SendNamedChannel(const base::StringPiece16& pipe_name) {
+void BrokerHost::SendNamedChannel(base::WStringPiece pipe_name) {
   InitData* data;
-  base::char16* name_data;
+  wchar_t* name_data;
   Channel::MessagePtr message = CreateBrokerMessage(
       BrokerMessageType::INIT, 0, sizeof(*name_data) * pipe_name.length(),
       &data, reinterpret_cast<void**>(&name_data));

mojo/core/broker_host.h

@@ -37,7 +37,7 @@ class BrokerHost : public Channel::Delegate,
 
 #if defined(OS_WIN)
   // Sends a named channel to the client. Like above, but for named pipes.
-  void SendNamedChannel(const base::StringPiece16& pipe_name);
+  void SendNamedChannel(base::WStringPiece pipe_name);
 #endif
 
  private:

mojo/core/broker_win.cc

@@ -111,11 +111,10 @@ Broker::Broker(PlatformHandle handle, bool wait_for_channel_handle)
     CHECK_EQ(message->payload_size(),
              sizeof(BrokerMessageHeader) + sizeof(InitData) +
                  data->pipe_name_length * sizeof(base::char16));
-    const base::char16* name_data =
-        reinterpret_cast<const base::char16*>(data + 1);
+    auto* name_data = reinterpret_cast<const wchar_t*>(data + 1);
     CHECK(data->pipe_name_length);
     inviter_endpoint_ = NamedPlatformChannel::ConnectToServer(
-        base::string16(name_data, data->pipe_name_length));
+        NamedPlatformChannel::ServerName(name_data, data->pipe_name_length));
   }
 }
 

mojo/core/test/multiprocess_test_helper.cc

@@ -132,7 +132,7 @@ ScopedMessagePipeHandle MultiprocessTestHelper::StartChildWithExtraSwitch(
           temp_dir.AppendASCII(base::NumberToString(base::RandUint64()))
               .value();
 #elif defined(OS_WIN)
-      server_name = base::NumberToString16(base::RandUint64());
+      server_name = base::NumberToWString(base::RandUint64());
 #else
 #error "Platform not yet supported."
 #endif

mojo/public/cpp/base/file_path_mojom_traits.cc

@@ -14,8 +14,7 @@ bool StructTraits<mojo_base::mojom::FilePathDataView, base::FilePath>::Read(
 #if defined(OS_WIN)
   ArrayDataView<uint16_t> view;
   data.GetPathDataView(&view);
-  path_view = base::StringPiece16(
-      reinterpret_cast<const base::char16*>(view.data()), view.size());
+  path_view = {reinterpret_cast<const wchar_t*>(view.data()), view.size()};
 #else
   if (!data.ReadPath(&path_view)) {
     return false;

mojo/public/cpp/platform/named_platform_channel.cc

@@ -29,7 +29,7 @@ NamedPlatformChannel& NamedPlatformChannel::operator=(
 NamedPlatformChannel::ServerName NamedPlatformChannel::ServerNameFromUTF8(
     base::StringPiece name) {
 #if defined(OS_WIN)
-  return base::UTF8ToUTF16(name);
+  return base::UTF8ToWide(name);
 #else
   return name.as_string();
 #endif

mojo/public/cpp/platform/named_platform_channel.h

@@ -5,6 +5,8 @@
 #ifndef MOJO_PUBLIC_CPP_PLATFORM_NAMED_PLATFORM_CHANNEL_H_
 #define MOJO_PUBLIC_CPP_PLATFORM_NAMED_PLATFORM_CHANNEL_H_
 
+#include <string>
+
 #include "base/command_line.h"
 #include "base/component_export.h"
 #include "base/macros.h"
@@ -13,9 +15,7 @@
 #include "mojo/public/cpp/platform/platform_channel_endpoint.h"
 #include "mojo/public/cpp/platform/platform_channel_server_endpoint.h"
 
-#if defined(OS_WIN)
-#include "base/strings/string16.h"
-#elif defined(OS_POSIX)
+#if defined(OS_POSIX)
 #include "base/files/file_path.h"
 #endif
 
@@ -35,7 +35,7 @@ class COMPONENT_EXPORT(MOJO_CPP_PLATFORM) NamedPlatformChannel {
   static const char kNamedHandleSwitch[];
 
 #if defined(OS_WIN)
-  using ServerName = base::string16;
+  using ServerName = std::wstring;
 #else
   using ServerName = std::string;
 #endif
@@ -49,7 +49,7 @@ class COMPONENT_EXPORT(MOJO_CPP_PLATFORM) NamedPlatformChannel {
     // If non-empty, a security descriptor to use when creating the pipe. If
     // empty, a default security descriptor will be used. See
     // |kDefaultSecurityDescriptor|.
-    base::string16 security_descriptor;
+    std::wstring security_descriptor;
 
     // If |true|, only a server endpoint will be allowed with the given name and
     // only one client will be able to connect. Otherwise many

mojo/public/cpp/platform/named_platform_channel_win.cc

@@ -27,16 +27,15 @@ namespace {
 // SY = LOCAL_SYSTEM
 // BA = BUILTIN_ADMINISTRATORS
 // OW = OWNER_RIGHTS
-constexpr base::char16 kDefaultSecurityDescriptor[] =
+constexpr wchar_t kDefaultSecurityDescriptor[] =
     L"D:(A;;GA;;;SY)(A;;GA;;;BA)(A;;GA;;;OW)";
 
 NamedPlatformChannel::ServerName GenerateRandomServerName() {
-  return base::UTF8ToUTF16(
-      base::StringPrintf("%lu.%lu.%I64u", ::GetCurrentProcessId(),
-                         ::GetCurrentThreadId(), base::RandUint64()));
+  return base::StringPrintf(L"%lu.%lu.%I64u", ::GetCurrentProcessId(),
+                            ::GetCurrentThreadId(), base::RandUint64());
 }
 
-base::string16 GetPipeNameFromServerName(
+std::wstring GetPipeNameFromServerName(
     const NamedPlatformChannel::ServerName& server_name) {
   return L"\\\\.\\pipe\\mojo." + server_name;
 }
@@ -68,7 +67,7 @@ PlatformChannelServerEndpoint NamedPlatformChannel::CreateServerEndpoint(
   const DWORD kPipeMode =
       PIPE_TYPE_BYTE | PIPE_READMODE_BYTE | PIPE_REJECT_REMOTE_CLIENTS;
 
-  base::string16 pipe_name = GetPipeNameFromServerName(name);
+  std::wstring pipe_name = GetPipeNameFromServerName(name);
   PlatformHandle handle(base::win::ScopedHandle(::CreateNamedPipeW(
       pipe_name.c_str(), kOpenMode, kPipeMode,
       options.enforce_uniqueness ? 1 : 255,  // Max instances.
@@ -84,7 +83,7 @@ PlatformChannelServerEndpoint NamedPlatformChannel::CreateServerEndpoint(
 // static
 PlatformChannelEndpoint NamedPlatformChannel::CreateClientEndpoint(
     const ServerName& server_name) {
-  base::string16 pipe_name = GetPipeNameFromServerName(server_name);
+  std::wstring pipe_name = GetPipeNameFromServerName(server_name);
 
   // Note: This may block.
   if (!::WaitNamedPipeW(pipe_name.c_str(), NMPWAIT_USE_DEFAULT_WAIT))

mojo/public/cpp/platform/platform_channel.cc

@@ -56,9 +56,9 @@ namespace {
 #if defined(OS_WIN)
 void CreateChannel(PlatformHandle* local_endpoint,
                    PlatformHandle* remote_endpoint) {
-  base::string16 pipe_name = base::UTF8ToUTF16(base::StringPrintf(
-      "\\\\.\\pipe\\mojo.%lu.%lu.%I64u", ::GetCurrentProcessId(),
-      ::GetCurrentThreadId(), base::RandUint64()));
+  std::wstring pipe_name = base::StringPrintf(
+      L"\\\\.\\pipe\\mojo.%lu.%lu.%I64u", ::GetCurrentProcessId(),
+      ::GetCurrentThreadId(), base::RandUint64());
   DWORD kOpenMode =
       PIPE_ACCESS_DUPLEX | FILE_FLAG_OVERLAPPED | FILE_FLAG_FIRST_PIPE_INSTANCE;
   const DWORD kPipeMode = PIPE_TYPE_BYTE | PIPE_READMODE_BYTE;