[mojo-edk] Expose portable API for platform handle wrapping

mojo/edk/system/core.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/edk/system/core.h"
 
 #include <string.h>
 
 #include <utility>
 
@@ skipping 41 matching lines @@
 
 void CallWatchCallback(MojoWatchCallback callback,
                        uintptr_t context,
                        MojoResult result,
                        const HandleSignalsState& signals_state,
                        MojoWatchNotificationFlags flags) {
   callback(context, result, static_cast<MojoHandleSignalsState>(signals_state),
       flags);
 }
 
+MojoResult MojoPlatformHandleToScopedPlatformHandle(
+    const MojoPlatformHandle* platform_handle,
+ScopedPlatformHandle* out_handle) {

[Anand Mistry (off Chromium), 2016/05/23 07:16:52]

indenting

[Ken Rockot(use gerrit already), 2016/05/23 17:17:53]

done

+  if (platform_handle->struct_size != sizeof(MojoPlatformHandle))
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  if (platform_handle->type == MOJO_PLATFORM_HANDLE_TYPE_INVALID) {

[Anand Mistry (off Chromium), 2016/05/23 07:16:52]

This case exists twice with different error return codes. Which one is correct?

[Ken Rockot(use gerrit already), 2016/05/23 17:17:53]

Woops - the first one is correct. Removed the second, which was supposed to have
been deleted already.

+    out_handle->reset();
+    return MOJO_RESULT_OK;
+  }
+
+  PlatformHandle handle;
+  switch (platform_handle->type) {
+    case MOJO_PLATFORM_HANDLE_TYPE_INVALID:
+      return MOJO_RESULT_INVALID_ARGUMENT;
+
+#if defined(OS_POSIX)
+    case MOJO_PLATFORM_HANDLE_TYPE_FILE_DESCRIPTOR:
+      handle.handle = static_cast<int>(platform_handle->value);
+      break;
+#endif
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+    case MOJO_PLATFORM_HANDLE_TYPE_MACH_PORT:
+      handle.type = PlatformHandle::Type::MACH;
+      handle.port = static_cast<mach_port_t>(platform_handle->value);
+      break;
+#endif
+
+#if defined(OS_WIN)
+    case MOJO_PLATFORM_HANDLE_TYPE_WINDOWS_HANDLE:
+      handle.handle = reinterpret_cast<HANDLE>(platform_handle->value);
+      break;
+#endif
+
+    default:
+      return MOJO_RESULT_INVALID_ARGUMENT;
+  }
+
+  out_handle->reset(handle);
+  return MOJO_RESULT_OK;
+}
+
+MojoResult ScopedPlatformHandleToMojoPlatformHandle(
+    ScopedPlatformHandle handle,
+    MojoPlatformHandle* platform_handle) {
+  if (platform_handle->struct_size != sizeof(MojoPlatformHandle))
+    return MOJO_RESULT_INVALID_ARGUMENT;
+
+  if (!handle.is_valid()) {
+    platform_handle->type = MOJO_PLATFORM_HANDLE_TYPE_INVALID;
+    return MOJO_RESULT_OK;
+  }
+
+#if defined(OS_POSIX)
+  switch (handle.get().type) {
+    case PlatformHandle::Type::POSIX:
+      platform_handle->type = MOJO_PLATFORM_HANDLE_TYPE_FILE_DESCRIPTOR;
+      platform_handle->value = static_cast<uint64_t>(handle.release().handle);
+      break;
+
+#if defined(OS_MACOSX) && !defined(OS_IOS)
+    case PlatformHandle::Type::MACH:
+      platform_handle->type = MOJO_PLATFORM_HANDLE_TYPE_MACH_PORT;
+      platform_handle->value = static_cast<uint64_t>(handle.release().port);
+      break;
+#endif

[Anand Mistry (off Chromium), 2016/05/23 07:16:52]

#endif  // defined(OS_MACOSX) && !defined(OS_IOS)

For clarity since you have nested #ifs

[Ken Rockot(use gerrit already), 2016/05/23 17:17:53]

Done

+
+    default:
+      return MOJO_RESULT_INVALID_ARGUMENT;
+  }
+#elif defined(OS_WIN)
+  platform_handle->type = MOJO_PLATFORM_HANDLE_TYPE_WINDOWS_HANDLE;
+  platform_handle->value = reinterpret_cast<uint64_t>(handle.release().handle);
+#endif  // defined(OS_WIN)
+
+  return MOJO_RESULT_OK;
+}
+
 }  // namespace
 
 Core::Core() {}
 
 Core::~Core() {
   if (node_controller_ && node_controller_->io_task_runner()) {
     // If this races with IO thread shutdown the callback will be dropped and
     // the NodeController will be shutdown on this thread anyway, which is also
     // just fine.
     scoped_refptr<base::TaskRunner> io_task_runner =
@@ skipping 70 matching lines @@
 }
 
 MojoResult Core::PassWrappedPlatformHandle(
     MojoHandle wrapper_handle,
     ScopedPlatformHandle* platform_handle) {
   base::AutoLock lock(handles_lock_);
   scoped_refptr<Dispatcher> d;
   MojoResult result = handles_.GetAndRemoveDispatcher(wrapper_handle, &d);
   if (result != MOJO_RESULT_OK)
     return result;
-  PlatformHandleDispatcher* phd =
-      static_cast<PlatformHandleDispatcher*>(d.get());
-  *platform_handle = phd->PassPlatformHandle();
-  phd->Close();
-  return MOJO_RESULT_OK;
+  if (d->GetType() == Dispatcher::Type::PLATFORM_HANDLE) {
+    PlatformHandleDispatcher* phd =
+        static_cast<PlatformHandleDispatcher*>(d.get());
+    *platform_handle = phd->PassPlatformHandle();
+  } else {
+    result = MOJO_RESULT_INVALID_ARGUMENT;
+  }
+  d->Close();
+  return result;
 }
 
 MojoResult Core::CreateSharedBufferWrapper(
     base::SharedMemoryHandle shared_memory_handle,
     size_t num_bytes,
     bool read_only,
     MojoHandle* mojo_wrapper_handle) {
   DCHECK(num_bytes);
   scoped_refptr<PlatformSharedBuffer> platform_buffer =
       PlatformSharedBuffer::CreateFromSharedMemoryHandle(num_bytes, read_only,
@@ skipping 706 matching lines @@
   *buffer = address;
   return MOJO_RESULT_OK;
 }
 
 MojoResult Core::UnmapBuffer(void* buffer) {
   RequestContext request_context;
   base::AutoLock lock(mapping_table_lock_);
   return mapping_table_.RemoveMapping(buffer);
 }
 
+MojoResult Core::WrapPlatformHandle(const MojoPlatformHandle* platform_handle,
+                                    MojoHandle* mojo_handle) {
+  ScopedPlatformHandle handle;
+  MojoResult result = MojoPlatformHandleToScopedPlatformHandle(platform_handle,
+                                                               &handle);
+  if (result != MOJO_RESULT_OK)
+    return result;
+
+  return CreatePlatformHandleWrapper(std::move(handle), mojo_handle);
+}
+
+MojoResult Core::UnwrapPlatformHandle(MojoHandle mojo_handle,
+                                      MojoPlatformHandle* platform_handle) {
+  ScopedPlatformHandle handle;
+  MojoResult result = PassWrappedPlatformHandle(mojo_handle, &handle);
+  if (result != MOJO_RESULT_OK)
+    return result;
+
+  return ScopedPlatformHandleToMojoPlatformHandle(std::move(handle),
+                                                  platform_handle);
+}
+
+MojoResult Core::WrapPlatformSharedBufferHandle(
+    const MojoPlatformHandle* platform_handle,
+    size_t size,
+    MojoPlatformSharedBufferHandleFlags flags,
+    MojoHandle* mojo_handle) {
+  DCHECK(size);
+  ScopedPlatformHandle handle;
+  MojoResult result = MojoPlatformHandleToScopedPlatformHandle(platform_handle,
+                                                               &handle);
+  if (result != MOJO_RESULT_OK)
+    return result;
+
+  bool read_only = flags & MOJO_PLATFORM_SHARED_BUFFER_HANDLE_FLAG_READ_ONLY;
+  scoped_refptr<PlatformSharedBuffer> platform_buffer =
+      PlatformSharedBuffer::CreateFromPlatformHandle(size, read_only,
+                                                     std::move(handle));
+  if (!platform_buffer)
+    return MOJO_RESULT_UNKNOWN;
+
+  scoped_refptr<SharedBufferDispatcher> dispatcher;
+  result = SharedBufferDispatcher::CreateFromPlatformSharedBuffer(
+      platform_buffer, &dispatcher);
+  if (result != MOJO_RESULT_OK)
+    return result;
+
+  MojoHandle h = AddDispatcher(dispatcher);
+  if (h == MOJO_HANDLE_INVALID)
+    return MOJO_RESULT_RESOURCE_EXHAUSTED;

[Anand Mistry (off Chromium), 2016/05/23 07:16:52]

You need to call Close() on the dispatcher if it wasn't successfully added.

[Ken Rockot(use gerrit already), 2016/05/23 17:17:53]

Done

+
+  *mojo_handle = h;
+  return MOJO_RESULT_OK;
+}
+
+MojoResult Core::UnwrapPlatformSharedBufferHandle(
+    MojoHandle mojo_handle,
+    MojoPlatformHandle* platform_handle,
+    size_t* size,
+    MojoPlatformSharedBufferHandleFlags* flags) {
+  scoped_refptr<Dispatcher> dispatcher;
+  MojoResult result = MOJO_RESULT_OK;
+  {
+    base::AutoLock lock(handles_lock_);
+    result = handles_.GetAndRemoveDispatcher(mojo_handle, &dispatcher);
+    if (result != MOJO_RESULT_OK)
+      return result;
+  }
+
+  if (dispatcher->GetType() != Dispatcher::Type::SHARED_BUFFER) {
+    dispatcher->Close();
+    return MOJO_RESULT_INVALID_ARGUMENT;
+  }
+
+  SharedBufferDispatcher* shm_dispatcher =
+      static_cast<SharedBufferDispatcher*>(dispatcher.get());
+  scoped_refptr<PlatformSharedBuffer> platform_shared_buffer =
+      shm_dispatcher->PassPlatformSharedBuffer();
+  CHECK(platform_shared_buffer);
+
+  CHECK(size);
+  *size = platform_shared_buffer->GetNumBytes();
+
+  CHECK(flags);
+  *flags = MOJO_PLATFORM_SHARED_BUFFER_HANDLE_FLAG_NONE;
+  if (platform_shared_buffer->IsReadOnly())
+    *flags |= MOJO_PLATFORM_SHARED_BUFFER_HANDLE_FLAG_READ_ONLY;
+
+  ScopedPlatformHandle handle = platform_shared_buffer->PassPlatformHandle();
+  return ScopedPlatformHandleToMojoPlatformHandle(std::move(handle),
+                                                  platform_handle);
+}
+
 void Core::GetActiveHandlesForTest(std::vector<MojoHandle>* handles) {
   base::AutoLock lock(handles_lock_);
   handles_.GetActiveHandlesForTest(handles);
 }
 
 MojoResult Core::WaitManyInternal(const MojoHandle* handles,
                                   const MojoHandleSignals* signals,
                                   uint32_t num_handles,
                                   MojoDeadline deadline,
                                   uint32_t *result_index,
@@ skipping 65 matching lines @@
     std::unique_ptr<NodeController> node_controller) {
   // It's OK to leak this reference. At this point we know the IO loop is still
   // running, and we know the NodeController will observe its eventual
   // destruction. This tells the NodeController to delete itself when that
   // happens.
   node_controller.release()->DestroyOnIOThreadShutdown();
 }
 
 }  // namespace edk
 }  // namespace mojo