/* Copyright 2015 The TensorFlow Authors. All Rights Reserved.

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

    http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
==============================================================================*/

#include "tensorflow/core/common_runtime/device_mgr.h"

#include <memory>
#include <vector>
#include "tensorflow/core/common_runtime/local_device.h"
#include "tensorflow/core/framework/device_attributes.pb.h"
#include "tensorflow/core/lib/core/errors.h"
#include "tensorflow/core/platform/logging.h"
#include "tensorflow/core/util/device_name_utils.h"

namespace tensorflow {

DeviceMgr::DeviceMgr(std::vector<std::unique_ptr<Device>> devices)
    : devices_(std::move(devices)), name_backing_store_(128) {
  for (auto& d : devices_) {
    // Register under the (1) full name and (2) canonical name.
    for (const string& name :
         DeviceNameUtils::GetNamesForDeviceMappings(d->parsed_name())) {
      device_map_[CopyToBackingStore(name)] = d.get();
    }
    // Register under the (3) local name and (4) legacy local name.
    for (const string& name :
         DeviceNameUtils::GetLocalNamesForDeviceMappings(d->parsed_name())) {
      device_map_[CopyToBackingStore(name)] = d.get();
    }
    device_type_counts_[d->device_type()]++;
  }
}

DeviceMgr::DeviceMgr(std::unique_ptr<Device> device)
    : DeviceMgr([&device] {
        std::vector<std::unique_ptr<Device>> vector;
        vector.push_back(std::move(device));
        return vector;
      }()) {}

DeviceMgr::~DeviceMgr() {
  // Release resources ahead of destroying the device manager as the resource
  // destructors (e.g. ~IteratorResource) assume devices still exist.
  for (auto& device : devices_) {
    device->ClearResourceMgr();
  }
}

StringPiece DeviceMgr::CopyToBackingStore(StringPiece s) {
  size_t n = s.size();
  char* space = name_backing_store_.Alloc(n);
  memcpy(space, s.data(), n);
  return StringPiece(space, n);
}

void DeviceMgr::ListDeviceAttributes(
    std::vector<DeviceAttributes>* devices) const {
  devices->reserve(devices_.size());
  for (const auto& dev : devices_) {
    devices->emplace_back(dev->attributes());
  }
}

std::vector<Device*> DeviceMgr::ListDevices() const {
  std::vector<Device*> devices(devices_.size());
  for (size_t i = 0; i < devices_.size(); ++i) {
    devices[i] = devices_[i].get();
  }
  return devices;
}

string DeviceMgr::DebugString() const {
  string out;
  for (const auto& dev : devices_) {
    strings::StrAppend(&out, dev->name(), "\n");
  }
  return out;
}

string DeviceMgr::DeviceMappingString() const {
  string out;
  for (const auto& dev : devices_) {
    if (!dev->attributes().physical_device_desc().empty()) {
      strings::StrAppend(&out, dev->name(), " -> ",
                         dev->attributes().physical_device_desc(), "\n");
    }
  }
  return out;
}

Status DeviceMgr::LookupDevice(StringPiece name, Device** device) const {
  auto iter = device_map_.find(name);
  if (iter == device_map_.end()) {
    std::vector<StringPiece> device_names;
    for (auto&& itr : device_map_) {
      device_names.push_back(itr.first);
    }
    VLOG(1) << "Unknown device: " << name
            << " all devices: " << absl::StrJoin(device_names, ", ");
    return errors::InvalidArgument(name, " unknown device.");
  }
  *device = iter->second;
  return Status::OK();
}

void DeviceMgr::ClearContainers(gtl::ArraySlice<string> containers) const {
  Status s;
  for (const auto& dev : devices_) {
    if (containers.empty()) {
      s.Update(dev->resource_manager()->Cleanup(
          dev->resource_manager()->default_container()));
    } else {
      for (const string& c : containers) {
        s.Update(dev->resource_manager()->Cleanup(c));
      }
    }
    if (!s.ok()) {
      LOG(WARNING) << s;
    }
  }
}

int DeviceMgr::NumDeviceType(const string& type) const {
  auto iter = device_type_counts_.find(type);
  if (iter != device_type_counts_.end()) return iter->second;
  return 0;
}

}  // namespace tensorflow
