Make mojo_system static and mojo_system_impl a component, never use both

mojo/public/platform/native/system_thunks.cc

 // Copyright 2013 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/system/core_private.h"
+#include "mojo/public/platform/native/system_thunks.h"
 
 #include <assert.h>
 #include <stddef.h>
 
-static mojo::Core* g_core = NULL;
-
 extern "C" {
 
+static MojoSystemThunks g_thunks = {0};
+
 MojoTimeTicks MojoGetTimeTicksNow() {
-  assert(g_core);
-  return g_core->GetTimeTicksNow();
+  assert(g_thunks.GetTimeTicksNow);
+  return g_thunks.GetTimeTicksNow();
 }
 
 MojoResult MojoClose(MojoHandle handle) {
-  assert(g_core);
-  return g_core->Close(handle);
+  assert(g_thunks.Close);
+  return g_thunks.Close(handle);
 }
 
 MojoResult MojoWait(MojoHandle handle,
                     MojoWaitFlags flags,
                     MojoDeadline deadline) {
-  assert(g_core);
-  return g_core->Wait(handle, flags, deadline);
+  assert(g_thunks.Wait);
+  return g_thunks.Wait(handle, flags, deadline);
 }
 
 MojoResult MojoWaitMany(const MojoHandle* handles,
                         const MojoWaitFlags* flags,
                         uint32_t num_handles,
                         MojoDeadline deadline) {
-  assert(g_core);
-  return g_core->WaitMany(handles, flags, num_handles, deadline);
+  assert(g_thunks.WaitMany);
+  return g_thunks.WaitMany(handles, flags, num_handles, deadline);
 }
 
 MojoResult MojoCreateMessagePipe(MojoHandle* message_pipe_handle0,
                                  MojoHandle* message_pipe_handle1) {
-  assert(g_core);
-  return g_core->CreateMessagePipe(message_pipe_handle0, message_pipe_handle1);
+  assert(g_thunks.CreateMessagePipe);
+  return g_thunks.CreateMessagePipe(message_pipe_handle0, message_pipe_handle1);
 }
 
 MojoResult MojoWriteMessage(MojoHandle message_pipe_handle,
                             const void* bytes,
                             uint32_t num_bytes,
                             const MojoHandle* handles,
                             uint32_t num_handles,
                             MojoWriteMessageFlags flags) {
-  assert(g_core);
-  return g_core->WriteMessage(message_pipe_handle, bytes, num_bytes, handles,
-                              num_handles, flags);
+  assert(g_thunks.WriteMessage);
+  return g_thunks.WriteMessage(message_pipe_handle, bytes, num_bytes, handles,
+                               num_handles, flags);
 }
 
 MojoResult MojoReadMessage(MojoHandle message_pipe_handle,
                            void* bytes,
                            uint32_t* num_bytes,
                            MojoHandle* handles,
                            uint32_t* num_handles,
                            MojoReadMessageFlags flags) {
-  assert(g_core);
-  return g_core->ReadMessage(message_pipe_handle, bytes, num_bytes, handles,
-                             num_handles, flags);
+  assert(g_thunks.ReadMessage);
+  return g_thunks.ReadMessage(message_pipe_handle, bytes, num_bytes, handles,
+                              num_handles, flags);
 }
 
 MojoResult MojoCreateDataPipe(const MojoCreateDataPipeOptions* options,
                               MojoHandle* data_pipe_producer_handle,
                               MojoHandle* data_pipe_consumer_handle) {
-  assert(g_core);
-  return g_core->CreateDataPipe(options, data_pipe_producer_handle,
-                                data_pipe_consumer_handle);
+  assert(g_thunks.CreateDataPipe);
+  return g_thunks.CreateDataPipe(options, data_pipe_producer_handle,
+                                 data_pipe_consumer_handle);
 }
 
 MojoResult MojoWriteData(MojoHandle data_pipe_producer_handle,
                          const void* elements,
                          uint32_t* num_elements,
                          MojoWriteDataFlags flags) {
-  assert(g_core);
-  return g_core->WriteData(data_pipe_producer_handle, elements, num_elements,
-                           flags);
+  assert(g_thunks.WriteData);
+  return g_thunks.WriteData(data_pipe_producer_handle, elements, num_elements,
+                            flags);
 }
 
 MojoResult MojoBeginWriteData(MojoHandle data_pipe_producer_handle,
                               void** buffer,
                               uint32_t* buffer_num_elements,
                               MojoWriteDataFlags flags) {
-  assert(g_core);
-  return g_core->BeginWriteData(data_pipe_producer_handle, buffer,
-                                buffer_num_elements, flags);
+  assert(g_thunks.BeginWriteData);
+  return g_thunks.BeginWriteData(data_pipe_producer_handle, buffer,
+                                 buffer_num_elements, flags);
 }
 
 MojoResult MojoEndWriteData(MojoHandle data_pipe_producer_handle,
                             uint32_t num_elements_written) {
-  assert(g_core);
-  return g_core->EndWriteData(data_pipe_producer_handle, num_elements_written);
+  assert(g_thunks.EndWriteData);
+  return g_thunks.EndWriteData(data_pipe_producer_handle, num_elements_written);
 }
 
 MojoResult MojoReadData(MojoHandle data_pipe_consumer_handle,
                         void* elements,
                         uint32_t* num_elements,
                         MojoReadDataFlags flags) {
-  assert(g_core);
-  return g_core->ReadData(data_pipe_consumer_handle, elements, num_elements,
-                          flags);
+  assert(g_thunks.ReadData);
+  return g_thunks.ReadData(data_pipe_consumer_handle, elements, num_elements,
+                           flags);
 }
 
 MojoResult MojoBeginReadData(MojoHandle data_pipe_consumer_handle,
                              const void** buffer,
                              uint32_t* buffer_num_elements,
                              MojoReadDataFlags flags) {
-  assert(g_core);
-  return g_core->BeginReadData(data_pipe_consumer_handle, buffer,
-                               buffer_num_elements, flags);
+  assert(g_thunks.BeginReadData);
+  return g_thunks.BeginReadData(data_pipe_consumer_handle, buffer,
+                                buffer_num_elements, flags);
 }
 
 MojoResult MojoEndReadData(MojoHandle data_pipe_consumer_handle,
                            uint32_t num_elements_read) {
-  assert(g_core);
-  return g_core->EndReadData(data_pipe_consumer_handle, num_elements_read);
+  assert(g_thunks.EndReadData);
+  return g_thunks.EndReadData(data_pipe_consumer_handle, num_elements_read);
 }
 
 MojoResult MojoCreateSharedBuffer(
     const struct MojoCreateSharedBufferOptions* options,
     uint64_t num_bytes,
     MojoHandle* shared_buffer_handle) {
-  assert(g_core);
-  return g_core->CreateSharedBuffer(options, num_bytes, shared_buffer_handle);
+  assert(g_thunks.CreateSharedBuffer);
+  return g_thunks.CreateSharedBuffer(options, num_bytes, shared_buffer_handle);
 }
 
 MojoResult MojoDuplicateBufferHandle(
     MojoHandle buffer_handle,
     const struct MojoDuplicateBufferHandleOptions* options,
     MojoHandle* new_buffer_handle) {
-  assert(g_core);
-  return g_core->DuplicateBufferHandle(buffer_handle, options,
-                                       new_buffer_handle);
+  assert(g_thunks.DuplicateBufferHandle);
+  return g_thunks.DuplicateBufferHandle(buffer_handle, options,
+                                        new_buffer_handle);
 }
 
 MojoResult MojoMapBuffer(MojoHandle buffer_handle,
                          uint64_t offset,
                          uint64_t num_bytes,
                          void** buffer,
                          MojoMapBufferFlags flags) {
-  assert(g_core);
-  return g_core->MapBuffer(buffer_handle, offset, num_bytes, buffer, flags);
+  assert(g_thunks.MapBuffer);
+  return g_thunks.MapBuffer(buffer_handle, offset, num_bytes, buffer, flags);
 }
 
 MojoResult MojoUnmapBuffer(void* buffer) {
-  assert(g_core);
-  return g_core->UnmapBuffer(buffer);
+  assert(g_thunks.UnmapBuffer);
+  return g_thunks.UnmapBuffer(buffer);
+}
+
+size_t MojoSetSystemThunks(const MojoSystemThunks* system_thunks) {
+  if (system_thunks->size >= sizeof(g_thunks))
+    g_thunks = *system_thunks;
+  return sizeof(g_thunks);
 }
 
 }  // extern "C"
-
-namespace mojo {
-
-Core::~Core() {
-}
-
-// static
-void Core::Init(Core* core) {
-  assert(!g_core);
-  g_core = core;
-}
-
-// static
-Core* Core::Get() {
-  return g_core;
-}
-
-// static
-void Core::Reset() {
-  g_core = NULL;
-}
-
-}  // namespace mojo