// Copyright (c) 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 "ppapi/proxy/serialized_handle.h"

#include "base/check_op.h"
#include "base/files/file.h"
#include "base/notreached.h"
#include "base/pickle.h"
#include "build/build_config.h"
#include "ipc/ipc_platform_file.h"

#if defined(OS_NACL)
#include <unistd.h>
#endif

namespace ppapi {
namespace proxy {

SerializedHandle::SerializedHandle()
    : type_(INVALID),
      descriptor_(IPC::InvalidPlatformFileForTransit()),
      open_flags_(0),
      file_io_(0) {
}

SerializedHandle::SerializedHandle(SerializedHandle&& other)
    : type_(other.type_),
      shm_region_(std::move(other.shm_region_)),
      descriptor_(other.descriptor_),
      open_flags_(other.open_flags_),
      file_io_(other.file_io_) {
  other.set_null();
}

SerializedHandle& SerializedHandle::operator=(SerializedHandle&& other) {
  Close();
  type_ = other.type_;
  shm_region_ = std::move(other.shm_region_);
  descriptor_ = other.descriptor_;
  open_flags_ = other.open_flags_;
  file_io_ = other.file_io_;
  other.set_null();
  return *this;
}

SerializedHandle::SerializedHandle(Type type_param)
    : type_(type_param),
      descriptor_(IPC::InvalidPlatformFileForTransit()),
      open_flags_(0),
      file_io_(0) {
}

SerializedHandle::SerializedHandle(base::ReadOnlySharedMemoryRegion region)
    : SerializedHandle(
          base::ReadOnlySharedMemoryRegion::TakeHandleForSerialization(
              std::move(region))) {}

SerializedHandle::SerializedHandle(base::UnsafeSharedMemoryRegion region)
    : SerializedHandle(
          base::UnsafeSharedMemoryRegion::TakeHandleForSerialization(
              std::move(region))) {}

SerializedHandle::SerializedHandle(
    base::subtle::PlatformSharedMemoryRegion region)
    : type_(SHARED_MEMORY_REGION),
      shm_region_(std::move(region)),
      descriptor_(IPC::InvalidPlatformFileForTransit()),
      open_flags_(0),
      file_io_(0) {
  // Writable regions are not supported.
  DCHECK_NE(shm_region_.GetMode(),
            base::subtle::PlatformSharedMemoryRegion::Mode::kWritable);
}

SerializedHandle::SerializedHandle(
    Type type,
    const IPC::PlatformFileForTransit& socket_descriptor)
    : type_(type),
      descriptor_(socket_descriptor),
      open_flags_(0),
      file_io_(0) {
}

bool SerializedHandle::IsHandleValid() const {
  switch (type_) {
    case SHARED_MEMORY_REGION:
      return shm_region_.IsValid();
    case SOCKET:
    case FILE:
      return !(IPC::InvalidPlatformFileForTransit() == descriptor_);
    case INVALID:
      return false;
    // No default so the compiler will warn us if a new type is added.
  }
  return false;
}

void SerializedHandle::Close() {
  if (IsHandleValid()) {
    switch (type_) {
      case INVALID:
        NOTREACHED();
        break;
      case SHARED_MEMORY_REGION:
        shm_region_ = base::subtle::PlatformSharedMemoryRegion();
        break;
      case SOCKET:
      case FILE:
        base::File file_closer = IPC::PlatformFileForTransitToFile(descriptor_);
        break;
      // No default so the compiler will warn us if a new type is added.
    }
  }
  set_null();
}

// static
void SerializedHandle::WriteHeader(const Header& hdr, base::Pickle* pickle) {
  pickle->WriteInt(hdr.type);
  if (hdr.type == FILE) {
    pickle->WriteInt(hdr.open_flags);
    pickle->WriteInt(hdr.file_io);
  }
}

// static
bool SerializedHandle::ReadHeader(base::PickleIterator* iter, Header* hdr) {
  *hdr = Header(INVALID, 0, 0);
  int type = 0;
  if (!iter->ReadInt(&type))
    return false;
  bool valid_type = false;
  switch (type) {
    case FILE: {
      int open_flags = 0;
      PP_Resource file_io = 0;
      if (!iter->ReadInt(&open_flags) || !iter->ReadInt(&file_io))
        return false;
      hdr->open_flags = open_flags;
      hdr->file_io = file_io;
      valid_type = true;
      break;
    }
    case SHARED_MEMORY_REGION:
    case SOCKET:
    case INVALID:
      valid_type = true;
      break;
    // No default so the compiler will warn us if a new type is added.
  }
  if (valid_type)
    hdr->type = Type(type);
  return valid_type;
}

}  // namespace proxy
}  // namespace ppapi