/*
 * Copyright (C) 2015 The Android Open Source Project
 *
 * 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.
 */

#ifndef ART_RUNTIME_OAT_FILE_MANAGER_H_
#define ART_RUNTIME_OAT_FILE_MANAGER_H_

#include <memory>
#include <set>
#include <string>
#include <unordered_map>
#include <vector>

#include "base/macros.h"
#include "base/mutex.h"

namespace art {

namespace gc {
namespace space {
class ImageSpace;
}  // namespace space
}  // namespace gc

class DexFile;
class OatFile;

// Class for dealing with oat file management.
//
// This class knows about all the loaded oat files and provides utility functions. The oat file
// pointers returned from functions are always valid.
class OatFileManager {
 public:
  OatFileManager() : have_non_pic_oat_file_(false) {}
  ~OatFileManager();

  // Add an oat file to the internal accounting, std::aborts if there already exists an oat file
  // with the same base address. Returns the oat file pointer from oat_file.
  const OatFile* RegisterOatFile(std::unique_ptr<const OatFile> oat_file)
      REQUIRES(!Locks::oat_file_manager_lock_);

  void UnRegisterAndDeleteOatFile(const OatFile* oat_file)
      REQUIRES(!Locks::oat_file_manager_lock_);

  // Find the first opened oat file with the same location, returns null if there are none.
  const OatFile* FindOpenedOatFileFromOatLocation(const std::string& oat_location) const
      REQUIRES(!Locks::oat_file_manager_lock_);

  // Attempt to reserve a location, returns false if it is already reserved or already in used by
  // an oat file.
  bool RegisterOatFileLocation(const std::string& oat_location)
      REQUIRES(!Locks::oat_file_count_lock_);

  // Unreserve oat file location, should only be used for error cases since RegisterOatFile will
  // remove the reserved location.
  void UnRegisterOatFileLocation(const std::string& oat_location)
      REQUIRES(!Locks::oat_file_count_lock_);

  // Returns true if we have a non pic oat file.
  bool HaveNonPicOatFile() const {
    return have_non_pic_oat_file_;
  }

  // Returns the boot image oat file.
  const OatFile* GetBootOatFile() const;

  // Returns the first non-image oat file in the class path.
  const OatFile* GetPrimaryOatFile() const REQUIRES(!Locks::oat_file_manager_lock_);

  // Return the oat file for an image, registers the oat file. Takes ownership of the imagespace's
  // underlying oat file.
  const OatFile* RegisterImageOatFile(gc::space::ImageSpace* space)
      REQUIRES(!Locks::oat_file_manager_lock_);

  // Finds or creates the oat file holding dex_location. Then loads and returns
  // all corresponding dex files (there may be more than one dex file loaded
  // in the case of multidex).
  // This may return the original, unquickened dex files if the oat file could
  // not be generated.
  //
  // Returns an empty vector if the dex files could not be loaded. In this
  // case, there will be at least one error message returned describing why no
  // dex files could not be loaded. The 'error_msgs' argument must not be
  // null, regardless of whether there is an error or not.
  //
  // This method should not be called with the mutator_lock_ held, because it
  // could end up starving GC if we need to generate or relocate any oat
  // files.
  std::vector<std::unique_ptr<const DexFile>> OpenDexFilesFromOat(
      const char* dex_location,
      const char* oat_location,
      /*out*/ const OatFile** out_oat_file,
      /*out*/ std::vector<std::string>* error_msgs)
      REQUIRES(!Locks::oat_file_manager_lock_, !Locks::mutator_lock_);

 private:
  // Check for duplicate class definitions of the given oat file against all open oat files.
  // Return true if there are any class definition collisions in the oat_file.
  bool HasCollisions(const OatFile* oat_file, /*out*/std::string* error_msg) const
      REQUIRES(!Locks::oat_file_manager_lock_);

  const OatFile* FindOpenedOatFileFromOatLocationLocked(const std::string& oat_location) const
      REQUIRES(Locks::oat_file_manager_lock_);

  std::set<std::unique_ptr<const OatFile>> oat_files_ GUARDED_BY(Locks::oat_file_manager_lock_);
  std::unordered_map<std::string, size_t> oat_file_count_ GUARDED_BY(Locks::oat_file_count_lock_);
  bool have_non_pic_oat_file_;
  DISALLOW_COPY_AND_ASSIGN(OatFileManager);
};

}  // namespace art

#endif  // ART_RUNTIME_OAT_FILE_MANAGER_H_