// 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.

#ifndef CHROME_BROWSER_PRIVACY_BLACKLIST_BLACKLIST_H_
#define CHROME_BROWSER_PRIVACY_BLACKLIST_BLACKLIST_H_

#include <string>
#include <vector>

#include "base/basictypes.h"
#include "base/linked_ptr.h"
#include "googleurl/src/gurl.h"
#include "net/url_request/url_request.h"

class FilePath;

////////////////////////////////////////////////////////////////////////////////
//
// Blacklist Class
//
// Represents a blacklist used to protect user from privacy and annoyances.
// A blacklist is essentially a map from resource-match patterns to filter-
// attributes. Each time a resources matches a pattern the filter-attributes
// are used to determine how the browser handles the matching resource.
////////////////////////////////////////////////////////////////////////////////
class Blacklist {
 public:
  class Entry;
  class Provider;

  typedef std::vector<linked_ptr<Entry> > EntryList;
  typedef std::vector<linked_ptr<Provider> > ProviderList;

  // Filter attributes (more to come):
  static const unsigned int kBlockAll;
  static const unsigned int kDontSendCookies;
  static const unsigned int kDontStoreCookies;
  static const unsigned int kDontPersistCookies;
  static const unsigned int kDontSendReferrer;
  static const unsigned int kDontSendUserAgent;
  static const unsigned int kBlockByType;
  static const unsigned int kBlockUnsecure;

  // Aggregate filter types:
  static const unsigned int kBlockRequest;
  static const unsigned int kBlockResponse;
  static const unsigned int kModifySentHeaders;
  static const unsigned int kModifyReceivedHeaders;
  static const unsigned int kFilterByHeaders;

  // Key used to access data attached to URLRequest objects.
  static const void* const kRequestDataKey;

  // Converts a stringized filter attribute (see above) back to its integer
  // value. Returns 0 on error.
  static unsigned int String2Attribute(const std::string&);

  // Blacklist entries come from a provider, defined by a name and source URL.
  class Provider {
   public:
    Provider() {}
    Provider(const char* name, const char* url) : name_(name), url_(url) {}

    const std::string& name() const { return name_; }
    void set_name(const std::string& name) { name_ = name; }

    const std::string& url() const { return url_; }
    void set_url(const std::string& url) { url_ = url; }

   private:
    std::string name_;
    std::string url_;
  };

  // A single blacklist entry which is returned when a URL matches one of
  // the patterns. Entry objects are owned by the Blacklist that stores them.
  class Entry {
   public:
    // Construct with given pattern.
    Entry(const std::string& pattern, const Provider* provider);

    // Returns the pattern which this entry matches.
    const std::string& pattern() const { return pattern_; }

    // Bitfield of filter-attributes matching the pattern.
    unsigned int attributes() const { return attributes_; }

    // Provider of this blacklist entry, used for assigning blame ;)
    const Provider* provider() const { return provider_; }

    // Returns true if the given type matches one of the types for which
    // the filter-attributes of this pattern apply. This needs only to be
    // checked for content-type specific rules, as determined by calling
    // attributes().
    bool MatchesType(const std::string&) const;

    // Returns true of the given URL is blocked, assumes it matches the
    // pattern of this entry.
    bool IsBlocked(const GURL&) const;

    void AddAttributes(unsigned int attributes);
    void AddType(const std::string& type);

    // Swap the contents of the internal types vector with the given vector.
    void SwapTypes(std::vector<std::string>* types);

   private:
    friend class BlacklistIO;

    // Merge the attributes and types of the given entry with this one.
    void Merge(const Entry& entry);

    std::string pattern_;
    unsigned int attributes_;
    std::vector<std::string> types_;

    // Points to the provider of this entry, the providers are all
    // owned by the blacklist.
    const Provider* provider_;
  };

  // A request may match one or more Blacklist rules. The Match class packages
  // all the matching entries behind a single interface with access to the
  // underlying set of entries so that we can display provider information.
  // Often a match must be applied after a URLRequest has started, so it gets
  // tagged with the Match object to avoid doing lookups more than once per
  // request.
  class Match : public URLRequest::UserData {
   public:
    // Functions that return combined results from all entries.
    unsigned int attributes() const { return attributes_; }
    bool MatchType(const std::string&) const;
    bool IsBlocked(const GURL&) const;

    // Access to individual entries, mostly for display/logging purposes.
    const std::vector<const Entry*>& entries() const { return entries_; }

   private:
    Match();
    void AddEntry(const Entry* entry);
    std::vector<const Entry*> entries_;
    unsigned int attributes_;  // Precomputed ORed attributes of entries.

    friend class Blacklist;  // Only blacklist constructs and sets these.
  };

  // Constructs an empty blacklist.
  Blacklist();

  // Destructor.
  ~Blacklist();

  // Adds a new entry to the blacklist. It is now owned by the blacklist.
  void AddEntry(Entry* entry);

  // Adds a new provider to the blacklist. It is now owned by the blacklist.
  void AddProvider(Provider* provider);

  EntryList::const_iterator entries_begin() const {
    return blacklist_.begin();
  }

  EntryList::const_iterator entries_end() const {
    return blacklist_.end();
  }

  ProviderList::const_iterator providers_begin() const {
    return providers_.begin();
  }

  ProviderList::const_iterator providers_end() const {
    return providers_.end();
  }

  // Returns a pointer to a Match structure holding all matching entries.
  // If no matching Entry is found, returns null. Ownership belongs to the
  // caller.
  Match* findMatch(const GURL&) const;

  // Helper to remove cookies from a header.
  static std::string StripCookies(const std::string&);

  // Helper to remove cookie expiration from a header.
  static std::string StripCookieExpiry(const std::string&);

 private:
  // Matches a pattern to a core URL which is host/path with all the other
  // optional parts (scheme, user, password, port) stripped away. Used only
  // internally but made static so that access can be given to tests.
  static bool Matches(const std::string& pattern, const std::string& url);

  EntryList blacklist_;
  ProviderList providers_;

  FRIEND_TEST(BlacklistTest, PatternMatch);
  DISALLOW_COPY_AND_ASSIGN(Blacklist);
};

#endif  // CHROME_BROWSER_PRIVACY_BLACKLIST_BLACKLIST_H_