// Copyright (c) 2009 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.

// TransportSecurityState maintains an in memory database containing the
// list of hosts that currently have transport security enabled. This
// singleton object deals with writing that data out to disk as needed and
// loading it at startup.

// At startup we need to load the transport security state from the
// disk. For the moment, we don't want to delay startup for this load, so we
// let the TransportSecurityState run for a while without being loaded.
// This means that it's possible for pages opened very quickly not to get the
// correct transport security information.
//
// To load the state, we schedule a Task on the file thread which loads,
// deserialises and configures the TransportSecurityState.
//
// The TransportSecurityState object supports running a callback function
// when it changes. This object registers the callback, pointing at itself.
//
// TransportSecurityState calls...
// TransportSecurityPersister::StateIsDirty
//   since the callback isn't allowed to block or reenter, we schedule a Task
//   on the file thread after some small amount of time
//
// ...
//
// TransportSecurityPersister::SerialiseState
//   copies the current state of the TransportSecurityState, serialises
//   and writes to disk.

#ifndef CHROME_BROWSER_TRANSPORT_SECURITY_PERSISTER_H_
#define CHROME_BROWSER_TRANSPORT_SECURITY_PERSISTER_H_

#include "base/file_path.h"
#include "base/lock.h"
#include "base/ref_counted.h"
#include "base/task.h"
#include "net/base/transport_security_state.h"

class TransportSecurityPersister
    : public base::RefCountedThreadSafe<TransportSecurityPersister>,
      public net::TransportSecurityState::Delegate {
 public:
  TransportSecurityPersister();
  void Initialize(net::TransportSecurityState* state,
                  const FilePath& profile_path);

  // Called by the TransportSecurityState when it changes its state.
  virtual void StateIsDirty(net::TransportSecurityState*);

 private:
  friend class base::RefCountedThreadSafe<TransportSecurityPersister>;

  ~TransportSecurityPersister();

  void Load();
  void CompleteLoad(const std::string& state);

  void Save();
  void CompleteSave(const std::string& state);

  // Used on the IO thread to coalesce writes to disk.
  ScopedRunnableMethodFactory<TransportSecurityPersister> save_coalescer_;

  scoped_refptr<net::TransportSecurityState>
      transport_security_state_;  // IO thread only.

  // The path to the file in which we store the serialised state.
  FilePath state_file_;
};

#endif  // CHROME_BROWSER_TRANSPORT_SECURITY_PERSISTER_H_