path: root/net/base/cookie_monster.h

// Copyright (c) 2010 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.

// Brought to you by the letter D and the number 2.

#ifndef NET_BASE_COOKIE_MONSTER_H_
#define NET_BASE_COOKIE_MONSTER_H_

#include <map>
#include <string>
#include <utility>
#include <vector>

#include "base/basictypes.h"
#include "base/histogram.h"
#include "base/lock.h"
#include "base/ref_counted.h"
#include "base/scoped_ptr.h"
#include "base/time.h"
#include "net/base/cookie_store.h"

class GURL;

namespace net {

// The cookie monster is the system for storing and retrieving cookies. It has
// an in-memory list of all cookies, and synchronizes non-session cookies to an
// optional permanent storage that implements the PersistentCookieStore
// interface.
//
// This class IS thread-safe. Normally, it is only used on the I/O thread, but
// is also accessed directly through Automation for UI testing.
//
// TODO(deanm) Implement CookieMonster, the cookie database.
//  - Verify that our domain enforcement and non-dotted handling is correct
class CookieMonster : public CookieStore {
 public:
  class CanonicalCookie;
  class Delegate;
  class ParsedCookie;
  class PersistentCookieStore;

  // NOTE(deanm):
  // I benchmarked hash_multimap vs multimap.  We're going to be query-heavy
  // so it would seem like hashing would help.  However they were very
  // close, with multimap being a tiny bit faster.  I think this is because
  // our map is at max around 1000 entries, and the additional complexity
  // for the hashing might not overcome the O(log(1000)) for querying
  // a multimap.  Also, multimap is standard, another reason to use it.
  typedef std::multimap<std::string, CanonicalCookie*> CookieMap;
  typedef std::pair<CookieMap::iterator, CookieMap::iterator> CookieMapItPair;
  typedef std::pair<std::string, CanonicalCookie*> KeyedCanonicalCookie;
  typedef std::vector<CanonicalCookie> CookieList;

  // The store passed in should not have had Init() called on it yet. This
  // class will take care of initializing it. The backing store is NOT owned by
  // this class, but it must remain valid for the duration of the cookie
  // monster's existence. If |store| is NULL, then no backing store will be
  // updated. If |delegate| is non-NULL, it will be notified on
  // creation/deletion of cookies.
  CookieMonster(PersistentCookieStore* store, Delegate* delegate);

#ifdef UNIT_TEST
  CookieMonster(PersistentCookieStore* store,
                Delegate* delegate,
                int last_access_threshold_milliseconds)
      : initialized_(false),
        store_(store),
        last_access_threshold_(base::TimeDelta::FromMilliseconds(
            last_access_threshold_milliseconds)),
        delegate_(delegate),
        last_statistic_record_time_(base::Time::Now()) {
    InitializeHistograms();
    SetDefaultCookieableSchemes();
  }
#endif

  // Parse the string with the cookie time (very forgivingly).
  static base::Time ParseCookieTime(const std::string& time_string);

  // Returns true if a domain string represents a host-only cookie,
  // i.e. it doesn't begin with a leading '.' character.
  static bool DomainIsHostOnly(const std::string& domain_string);

  // CookieStore implementation.
  virtual bool SetCookieWithOptions(const GURL& url,
                                    const std::string& cookie_line,
                                    const CookieOptions& options);
  virtual std::string GetCookiesWithOptions(const GURL& url,
                                            const CookieOptions& options);
  virtual void DeleteCookie(const GURL& url, const std::string& cookie_name);
  virtual CookieMonster* GetCookieMonster() { return this; }

  // Sets a cookie given explicit user-provided cookie attributes. The cookie
  // name, value, domain, etc. are each provided as separate strings. This
  // function expects each attribute to be well-formed. It will check for
  // disallowed characters (e.g. the ';' character is disallowed within the
  // cookie value attribute) and will return false without setting the cookie
  // if such characters are found.
  bool SetCookieWithDetails(const GURL& url,
                            const std::string& name,
                            const std::string& value,
                            const std::string& domain,
                            const std::string& path,
                            const base::Time& expiration_time,
                            bool secure, bool http_only);

  // Exposed for unit testing.
  bool SetCookieWithCreationTimeAndOptions(const GURL& url,
                                           const std::string& cookie_line,
                                           const base::Time& creation_time,
                                           const CookieOptions& options);
  bool SetCookieWithCreationTime(const GURL& url,
                                 const std::string& cookie_line,
                                 const base::Time& creation_time) {
    return SetCookieWithCreationTimeAndOptions(url, cookie_line, creation_time,
                                               CookieOptions());
  }

  // Returns all the cookies, for use in management UI, etc. This does not mark
  // the cookies as having been accessed.
  CookieList GetAllCookies();

  // Returns all the cookies, for use in management UI, etc. Filters results
  // using given url scheme, host / domain and path. This does not mark the
  // cookies as having been accessed.
  CookieList GetAllCookiesForURL(const GURL& url);

  // Delete all of the cookies.
  int DeleteAll(bool sync_to_store);
  // Delete all of the cookies that have a creation_date greater than or equal
  // to |delete_begin| and less than |delete_end|
  int DeleteAllCreatedBetween(const base::Time& delete_begin,
                              const base::Time& delete_end,
                              bool sync_to_store);
  // Delete all of the cookies that have a creation_date more recent than the
  // one passed into the function via |delete_after|.
  int DeleteAllCreatedAfter(const base::Time& delete_begin, bool sync_to_store);

  // Delete all cookies that match the host of the given URL
  // regardless of path.  This includes all http_only and secure cookies,
  // but does not include any domain cookies that may apply to this host.
  // Returns the number of cookies deleted.
  int DeleteAllForHost(const GURL& url);

  // Delete one specific cookie.
  bool DeleteCookie(const std::string& domain,
                    const CanonicalCookie& cookie,
                    bool sync_to_store);

  // Override the default list of schemes that are allowed to be set in
  // this cookie store.  Calling his overrides the value of
  // "enable_file_scheme_".
  // If this this method is called, it must be called before first use of
  // the instance (i.e. as part of the instance initialization process.)
  void SetCookieableSchemes(const char* schemes[], size_t num_schemes);

  // There are some unknowns about how to correctly handle file:// cookies,
  // and our implementation for this is not robust enough. This allows you
  // to enable support, but it should only be used for testing. Bug 1157243.
  // Must be called before creating a CookieMonster instance.
  static void EnableFileScheme();
  static bool enable_file_scheme_;

 private:
  ~CookieMonster();

  // Called by all non-static functions to ensure that the cookies store has
  // been initialized. This is not done during creating so it doesn't block
  // the window showing.
  // Note: this method should always be called with lock_ held.
  void InitIfNecessary() {
    if (!initialized_) {
      if (store_)
        InitStore();
      initialized_ = true;
    }
  }

  // Initializes the backing store and reads existing cookies from it.
  // Should only be called by InitIfNecessary().
  void InitStore();

  // Checks that |cookies_| matches our invariants, and tries to repair any
  // inconsistencies. (In other words, it does not have duplicate cookies).
  void EnsureCookiesMapIsValid();

  // Checks for any duplicate cookies for host |key|, which lie between
  // |begin| and |end|. If any are found, all but the most recent are deleted.
  // Returns the number of duplicate cookies that were deleted.
  int TrimDuplicateCookiesForHost(const std::string& key,
                                  CookieMap::iterator begin,
                                  CookieMap::iterator end);

  void SetDefaultCookieableSchemes();

  void FindCookiesForHostAndDomain(const GURL& url,
                                   const CookieOptions& options,
                                   bool update_access_time,
                                   std::vector<CanonicalCookie*>* cookies);

  void FindCookiesForKey(const std::string& key,
                         const GURL& url,
                         const CookieOptions& options,
                         const base::Time& current,
                         bool update_access_time,
                         std::vector<CanonicalCookie*>* cookies);

  // Delete any cookies that are equivalent to |ecc| (same path, key, etc).
  // If |skip_httponly| is true, httponly cookies will not be deleted.  The
  // return value with be true if |skip_httponly| skipped an httponly cookie.
  // NOTE: There should never be more than a single matching equivalent cookie.
  bool DeleteAnyEquivalentCookie(const std::string& key,
                                 const CanonicalCookie& ecc,
                                 bool skip_httponly);

  void InternalInsertCookie(const std::string& key,
                            CanonicalCookie* cc,
                            bool sync_to_store);

  // Helper function that sets a canonical cookie, deleting equivalents and
  // performing garbage collection.
  bool SetCanonicalCookie(scoped_ptr<CanonicalCookie>* cc,
                          const base::Time& creation_time,
                          const CookieOptions& options);

  void InternalUpdateCookieAccessTime(CanonicalCookie* cc);

  enum DeletionCause {
    DELETE_COOKIE_EXPLICIT,
    DELETE_COOKIE_OVERWRITE,
    DELETE_COOKIE_EXPIRED,
    DELETE_COOKIE_EVICTED,
    DELETE_COOKIE_DUPLICATE_IN_BACKING_STORE,
    DELETE_COOKIE_DONT_RECORD,
    DELETE_COOKIE_LAST_ENTRY = DELETE_COOKIE_DONT_RECORD
  };

  // |deletion_cause| argument is for collecting statistics.
  void InternalDeleteCookie(CookieMap::iterator it, bool sync_to_store,
                            DeletionCause deletion_cause);

  // If the number of cookies for host |key|, or globally, are over preset
  // maximums, garbage collects, first for the host and then globally, as
  // described by GarbageCollectRange().  The limits can be found as constants
  // at the top of the function body.
  //
  // Returns the number of cookies deleted (useful for debugging).
  int GarbageCollect(const base::Time& current, const std::string& key);

  // Deletes all expired cookies in |itpair|;
  // then, if the number of remaining cookies is greater than |num_max|,
  // collects the least recently accessed cookies until
  // (|num_max| - |num_purge|) cookies remain.
  //
  // Returns the number of cookies deleted.
  int GarbageCollectRange(const base::Time& current,
                          const CookieMapItPair& itpair,
                          size_t num_max,
                          size_t num_purge);

  // Helper for GarbageCollectRange(); can be called directly as well.  Deletes
  // all expired cookies in |itpair|.  If |cookie_its| is non-NULL, it is
  // populated with all the non-expired cookies from |itpair|.
  //
  // Returns the number of cookies deleted.
  int GarbageCollectExpired(const base::Time& current,
                            const CookieMapItPair& itpair,
                            std::vector<CookieMap::iterator>* cookie_its);

  bool HasCookieableScheme(const GURL& url);

  // Statistics support
  // Record statistics every kRecordStatisticsIntervalSeconds of uptime.
  static const int kRecordStatisticsIntervalSeconds = 10 * 60;

  // This function should be called repeatedly, and will record
  // statistics if a sufficient time period has passed.
  void RecordPeriodicStats(const base::Time& current_time);

  // Histogram variables; see CookieMonster::InitializeHistograms() in
  // cookie_monster.cc for details.
  scoped_refptr<Histogram> histogram_expiration_duration_minutes_;
  scoped_refptr<Histogram> histogram_between_access_interval_minutes_;
  scoped_refptr<Histogram> histogram_evicted_last_access_minutes_;
  scoped_refptr<Histogram> histogram_count_;
  scoped_refptr<Histogram> histogram_number_duplicate_db_cookies_;
  scoped_refptr<Histogram> histogram_cookie_deletion_cause_;

  // Initialize the above variables; should only be called from
  // the constructor.
  void InitializeHistograms();

  CookieMap cookies_;

  // Indicates whether the cookie store has been initialized. This happens
  // lazily in InitStoreIfNecessary().
  bool initialized_;

  scoped_refptr<PersistentCookieStore> store_;

  // The resolution of our time isn't enough, so we do something
  // ugly and increment when we've seen the same time twice.
  base::Time CurrentTime();
  base::Time last_time_seen_;

  // Minimum delay after updating a cookie's LastAccessDate before we will
  // update it again.
  const base::TimeDelta last_access_threshold_;

  std::vector<std::string> cookieable_schemes_;

  scoped_refptr<Delegate> delegate_;

  // Lock for thread-safety
  Lock lock_;

  base::Time last_statistic_record_time_;

  DISALLOW_COPY_AND_ASSIGN(CookieMonster);
};

class CookieMonster::CanonicalCookie {
 public:

  // These constructors do no validation or canonicalization of their inputs;
  // the resulting CanonicalCookies should not be relied on to be canonical
  // unless the caller has done appropriate validation and canonicalization
  // themselves.
  CanonicalCookie() { }
  CanonicalCookie(const std::string& name,
                  const std::string& value,
                  const std::string& domain,
                  const std::string& path,
                  bool secure,
                  bool httponly,
                  const base::Time& creation,
                  const base::Time& last_access,
                  bool has_expires,
                  const base::Time& expires)
      : name_(name),
        value_(value),
        domain_(domain),
        path_(path),
        creation_date_(creation),
        last_access_date_(last_access),
        expiry_date_(expires),
        has_expires_(has_expires),
        secure_(secure),
        httponly_(httponly) {
  }

  // This constructor does canonicalization but not validation.
  // The result of this constructor should not be relied on in contexts
  // in which pre-validation of the ParsedCookie has not been done.
  CanonicalCookie(const GURL& url, const ParsedCookie& pc);

  // Supports the default copy constructor.

  // Creates a canonical cookie from unparsed attribute values.
  // Canonicalizes and validates inputs.  May return NULL if an attribute
  // value is invalid.
  static CanonicalCookie* Create(
      const GURL& url, const std::string& name, const std::string& value,
      const std::string& domain, const std::string& path,
      const base::Time& creation_time, const base::Time& expiration_time,
      bool secure, bool http_only);

  const std::string& Name() const { return name_; }
  const std::string& Value() const { return value_; }
  const std::string& Domain() const { return domain_; }
  const std::string& Path() const { return path_; }
  const base::Time& CreationDate() const { return creation_date_; }
  const base::Time& LastAccessDate() const { return last_access_date_; }
  bool DoesExpire() const { return has_expires_; }
  bool IsPersistent() const { return DoesExpire(); }
  const base::Time& ExpiryDate() const { return expiry_date_; }
  bool IsSecure() const { return secure_; }
  bool IsHttpOnly() const { return httponly_; }

  bool IsExpired(const base::Time& current) {
    return has_expires_ && current >= expiry_date_;
  }

  // Are the cookies considered equivalent in the eyes of RFC 2965.
  // The RFC says that name must match (case-sensitive), domain must
  // match (case insensitive), and path must match (case sensitive).
  // For the case insensitive domain compare, we rely on the domain
  // having been canonicalized (in
  // GetCookieDomainKeyWithString->CanonicalizeHost).
  bool IsEquivalent(const CanonicalCookie& ecc) const {
    // It seems like it would make sense to take secure and httponly into
    // account, but the RFC doesn't specify this.
    // NOTE: Keep this logic in-sync with TrimDuplicateCookiesForHost().
    return (name_ == ecc.Name() && domain_ == ecc.Domain()
            && path_ == ecc.Path());
  }

  void SetLastAccessDate(const base::Time& date) {
    last_access_date_ = date;
  }

  bool IsOnPath(const std::string& url_path) const;

  std::string DebugString() const;
 private:
  std::string name_;
  std::string value_;
  std::string domain_;
  std::string path_;
  base::Time creation_date_;
  base::Time last_access_date_;
  base::Time expiry_date_;
  bool has_expires_;
  bool secure_;
  bool httponly_;
};

class CookieMonster::Delegate
    : public base::RefCountedThreadSafe<CookieMonster::Delegate> {
 public:
  // Will be called when a cookie is added or removed. The function is passed
  // the respective |cookie| which was added to or removed from the cookies.
  // If |removed| is true, the cookie was deleted.
  virtual void OnCookieChanged(const CookieMonster::CanonicalCookie& cookie,
                               bool removed) = 0;
 protected:
  friend class base::RefCountedThreadSafe<CookieMonster::Delegate>;
  virtual ~Delegate() {}
};

class CookieMonster::ParsedCookie {
 public:
  typedef std::pair<std::string, std::string> TokenValuePair;
  typedef std::vector<TokenValuePair> PairList;

  // The maximum length of a cookie string we will try to parse
  static const size_t kMaxCookieSize = 4096;
  // The maximum number of Token/Value pairs.  Shouldn't have more than 8.
  static const int kMaxPairs = 16;

  // Construct from a cookie string like "BLAH=1; path=/; domain=.google.com"
  ParsedCookie(const std::string& cookie_line);
  ~ParsedCookie() { }

  // You should not call any other methods on the class if !IsValid
  bool IsValid() const { return is_valid_; }

  const std::string& Name() const { return pairs_[0].first; }
  const std::string& Token() const { return Name(); }
  const std::string& Value() const { return pairs_[0].second; }

  bool HasPath() const { return path_index_ != 0; }
  const std::string& Path() const { return pairs_[path_index_].second; }
  bool HasDomain() const { return domain_index_ != 0; }
  const std::string& Domain() const { return pairs_[domain_index_].second; }
  bool HasExpires() const { return expires_index_ != 0; }
  const std::string& Expires() const { return pairs_[expires_index_].second; }
  bool HasMaxAge() const { return maxage_index_ != 0; }
  const std::string& MaxAge() const { return pairs_[maxage_index_].second; }
  bool IsSecure() const { return secure_index_ != 0; }
  bool IsHttpOnly() const { return httponly_index_ != 0; }

  // Returns the number of attributes, for example, returning 2 for:
  //   "BLAH=hah; path=/; domain=.google.com"
  size_t NumberOfAttributes() const { return pairs_.size() - 1; }

  // For debugging only!
  std::string DebugString() const;

  // Returns an iterator pointing to the first terminator character found in
  // the given string.
  static std::string::const_iterator FindFirstTerminator(const std::string& s);

  // Given iterators pointing to the beginning and end of a string segment,
  // returns as output arguments token_start and token_end to the start and end
  // positions of a cookie attribute token name parsed from the segment, and
  // updates the segment iterator to point to the next segment to be parsed.
  // If no token is found, the function returns false.
  static bool ParseToken(std::string::const_iterator* it,
                         const std::string::const_iterator& end,
                         std::string::const_iterator* token_start,
                         std::string::const_iterator* token_end);

  // Given iterators pointing to the beginning and end of a string segment,
  // returns as output arguments value_start and value_end to the start and end
  // positions of a cookie attribute value parsed from the segment, and updates
  // the segment iterator to point to the next segment to be parsed.
  static void ParseValue(std::string::const_iterator* it,
                         const std::string::const_iterator& end,
                         std::string::const_iterator* value_start,
                         std::string::const_iterator* value_end);

  // Same as the above functions, except the input is assumed to contain the
  // desired token/value and nothing else.
  static std::string ParseTokenString(const std::string& token);
  static std::string ParseValueString(const std::string& value);

 private:
  static const char kTerminator[];
  static const int  kTerminatorLen;
  static const char kWhitespace[];
  static const char kValueSeparator[];
  static const char kTokenSeparator[];

  void ParseTokenValuePairs(const std::string& cookie_line);
  void SetupAttributes();

  PairList pairs_;
  bool is_valid_;
  // These will default to 0, but that should never be valid since the
  // 0th index is the user supplied token/value, not an attribute.
  // We're really never going to have more than like 8 attributes, so we
  // could fit these into 3 bits each if we're worried about size...
  size_t path_index_;
  size_t domain_index_;
  size_t expires_index_;
  size_t maxage_index_;
  size_t secure_index_;
  size_t httponly_index_;

  DISALLOW_COPY_AND_ASSIGN(ParsedCookie);
};

typedef base::RefCountedThreadSafe<CookieMonster::PersistentCookieStore>
    RefcountedPersistentCookieStore;

class CookieMonster::PersistentCookieStore
    : public RefcountedPersistentCookieStore {
 public:
  virtual ~PersistentCookieStore() { }

  // Initializes the store and retrieves the existing cookies. This will be
  // called only once at startup.
  virtual bool Load(std::vector<CookieMonster::KeyedCanonicalCookie>*) = 0;

  virtual void AddCookie(const std::string&, const CanonicalCookie&) = 0;
  virtual void UpdateCookieAccessTime(const CanonicalCookie&) = 0;
  virtual void DeleteCookie(const CanonicalCookie&) = 0;

 protected:
  PersistentCookieStore() { }

 private:
  DISALLOW_COPY_AND_ASSIGN(PersistentCookieStore);
};

}  // namespace net

#endif  // NET_BASE_COOKIE_MONSTER_H_