root/chrome/browser/download/download_query.cc

DEFINITIONS

1. GetAs
2. GetAs
3. GetAs
4. GetAs
5. GetAs
6. MatchesQuery
7. GetStartTimeMsEpoch
8. GetEndTimeMsEpoch
9. TimeToISO8601
10. GetStartTime
11. GetEndTime
12. GetDangerAccepted
13. GetExists
14. GetFilename
15. GetFilenameUTF8
16. GetUrl
17. GetState
18. GetDangerType
19. GetReceivedBytes
20. GetTotalBytes
21. GetMimeType
22. IsPaused
23. FieldMatches
24. BuildFilter
25. FindRegex
26. BuildRegexFilter
27. Compare
28. AddFilter
29. AddFilter
30. AddFilter
31. AddFilter
32. Matches
33. DownloadComparator
34. AddSorter
35. FinishSearch

// Copyright (c) 2012 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.

#include "chrome/browser/download/download_query.h"

#include <algorithm>
#include <string>
#include <vector>

#include "base/bind.h"
#include "base/callback.h"
#include "base/files/file_path.h"
#include "base/i18n/case_conversion.h"
#include "base/i18n/string_search.h"
#include "base/logging.h"
#include "base/memory/scoped_ptr.h"
#include "base/prefs/pref_service.h"
#include "base/stl_util.h"
#include "base/strings/string16.h"
#include "base/strings/string_split.h"
#include "base/strings/stringprintf.h"
#include "base/strings/utf_string_conversions.h"
#include "base/time/time.h"
#include "base/values.h"
#include "chrome/browser/profiles/profile.h"
#include "chrome/common/pref_names.h"
#include "content/public/browser/content_browser_client.h"
#include "content/public/browser/download_item.h"
#include "net/base/net_util.h"
#include "third_party/re2/re2/re2.h"
#include "url/gurl.h"

using content::DownloadDangerType;
using content::DownloadItem;

namespace {

// Templatized base::Value::GetAs*().
template <typename T> bool GetAs(const base::Value& in, T* out);
template<> bool GetAs(const base::Value& in, bool* out) {
  return in.GetAsBoolean(out);
}
template<> bool GetAs(const base::Value& in, int* out) {
  return in.GetAsInteger(out);
}
template<> bool GetAs(const base::Value& in, std::string* out) {
  return in.GetAsString(out);
}
template<> bool GetAs(const base::Value& in, base::string16* out) {
  return in.GetAsString(out);
}
template<> bool GetAs(const base::Value& in, std::vector<base::string16>* out) {
  out->clear();
  const base::ListValue* list = NULL;
  if (!in.GetAsList(&list))
    return false;
  for (size_t i = 0; i < list->GetSize(); ++i) {
    base::string16 element;
    if (!list->GetString(i, &element)) {
      out->clear();
      return false;
    }
    out->push_back(element);
  }
  return true;
}

// The next several functions are helpers for making Callbacks that access
// DownloadItem fields.

static bool MatchesQuery(
    const std::vector<base::string16>& query_terms,
    const DownloadItem& item) {
  DCHECK(!query_terms.empty());
  base::string16 url_raw(base::UTF8ToUTF16(item.GetOriginalUrl().spec()));
  base::string16 url_formatted = url_raw;
  if (item.GetBrowserContext()) {
    Profile* profile = Profile::FromBrowserContext(item.GetBrowserContext());
    url_formatted = net::FormatUrl(
        item.GetOriginalUrl(),
        profile->GetPrefs()->GetString(prefs::kAcceptLanguages));
  }
  base::string16 path(item.GetTargetFilePath().LossyDisplayName());

  for (std::vector<base::string16>::const_iterator it = query_terms.begin();
       it != query_terms.end(); ++it) {
    base::string16 term = base::i18n::ToLower(*it);
    if (!base::i18n::StringSearchIgnoringCaseAndAccents(
            term, url_raw, NULL, NULL) &&
        !base::i18n::StringSearchIgnoringCaseAndAccents(
            term, url_formatted, NULL, NULL) &&
        !base::i18n::StringSearchIgnoringCaseAndAccents(
            term, path, NULL, NULL)) {
      return false;
    }
  }
  return true;
}

static int64 GetStartTimeMsEpoch(const DownloadItem& item) {
  return (item.GetStartTime() - base::Time::UnixEpoch()).InMilliseconds();
}

static int64 GetEndTimeMsEpoch(const DownloadItem& item) {
  return (item.GetEndTime() - base::Time::UnixEpoch()).InMilliseconds();
}

std::string TimeToISO8601(const base::Time& t) {
  base::Time::Exploded exploded;
  t.UTCExplode(&exploded);
  return base::StringPrintf(
      "%04d-%02d-%02dT%02d:%02d:%02d.%03dZ", exploded.year, exploded.month,
      exploded.day_of_month, exploded.hour, exploded.minute, exploded.second,
      exploded.millisecond);
}

static std::string GetStartTime(const DownloadItem& item) {
  return TimeToISO8601(item.GetStartTime());
}

static std::string GetEndTime(const DownloadItem& item) {
  return TimeToISO8601(item.GetEndTime());
}

static bool GetDangerAccepted(const DownloadItem& item) {
  return (item.GetDangerType() ==
          content::DOWNLOAD_DANGER_TYPE_USER_VALIDATED);
}

static bool GetExists(const DownloadItem& item) {
  return !item.GetFileExternallyRemoved();
}

static base::string16 GetFilename(const DownloadItem& item) {
  // This filename will be compared with strings that could be passed in by the
  // user, who only sees LossyDisplayNames.
  return item.GetTargetFilePath().LossyDisplayName();
}

static std::string GetFilenameUTF8(const DownloadItem& item) {
  return base::UTF16ToUTF8(GetFilename(item));
}

static std::string GetUrl(const DownloadItem& item) {
  return item.GetOriginalUrl().spec();
}

static DownloadItem::DownloadState GetState(const DownloadItem& item) {
  return item.GetState();
}

static DownloadDangerType GetDangerType(const DownloadItem& item) {
  return item.GetDangerType();
}

static int GetReceivedBytes(const DownloadItem& item) {
  return item.GetReceivedBytes();
}

static int GetTotalBytes(const DownloadItem& item) {
  return item.GetTotalBytes();
}

static std::string GetMimeType(const DownloadItem& item) {
  return item.GetMimeType();
}

static bool IsPaused(const DownloadItem& item) {
  return item.IsPaused();
}

enum ComparisonType {LT, EQ, GT};

// Returns true if |item| matches the filter specified by |value|, |cmptype|,
// and |accessor|. |accessor| is conceptually a function that takes a
// DownloadItem and returns one of its fields, which is then compared to
// |value|.
template<typename ValueType>
static bool FieldMatches(
    const ValueType& value,
    ComparisonType cmptype,
    const base::Callback<ValueType(const DownloadItem&)>& accessor,
    const DownloadItem& item) {
  switch (cmptype) {
    case LT: return accessor.Run(item) < value;
    case EQ: return accessor.Run(item) == value;
    case GT: return accessor.Run(item) > value;
  }
  NOTREACHED();
  return false;
}

// Helper for building a Callback to FieldMatches<>().
template <typename ValueType> DownloadQuery::FilterCallback BuildFilter(
    const base::Value& value, ComparisonType cmptype,
    ValueType (*accessor)(const DownloadItem&)) {
  ValueType cpp_value;
  if (!GetAs(value, &cpp_value)) return DownloadQuery::FilterCallback();
  return base::Bind(&FieldMatches<ValueType>, cpp_value, cmptype,
                    base::Bind(accessor));
}

// Returns true if |accessor.Run(item)| matches |pattern|.
static bool FindRegex(
    RE2* pattern,
    const base::Callback<std::string(const DownloadItem&)>& accessor,
    const DownloadItem& item) {
  return RE2::PartialMatch(accessor.Run(item), *pattern);
}

// Helper for building a Callback to FindRegex().
DownloadQuery::FilterCallback BuildRegexFilter(
    const base::Value& regex_value,
    std::string (*accessor)(const DownloadItem&)) {
  std::string regex_str;
  if (!GetAs(regex_value, &regex_str)) return DownloadQuery::FilterCallback();
  scoped_ptr<RE2> pattern(new RE2(regex_str));
  if (!pattern->ok()) return DownloadQuery::FilterCallback();
  return base::Bind(&FindRegex, base::Owned(pattern.release()),
                    base::Bind(accessor));
}

// Returns a ComparisonType to indicate whether a field in |left| is less than,
// greater than or equal to the same field in |right|.
template<typename ValueType>
static ComparisonType Compare(
    const base::Callback<ValueType(const DownloadItem&)>& accessor,
    const DownloadItem& left, const DownloadItem& right) {
  ValueType left_value = accessor.Run(left);
  ValueType right_value = accessor.Run(right);
  if (left_value > right_value) return GT;
  if (left_value < right_value) return LT;
  DCHECK_EQ(left_value, right_value);
  return EQ;
}

}  // anonymous namespace

DownloadQuery::DownloadQuery()
  : limit_(kuint32max) {
}

DownloadQuery::~DownloadQuery() {
}

// AddFilter() pushes a new FilterCallback to filters_. Most FilterCallbacks are
// Callbacks to FieldMatches<>(). Search() iterates over given DownloadItems,
// discarding items for which any filter returns false. A DownloadQuery may have
// zero or more FilterCallbacks.

bool DownloadQuery::AddFilter(const DownloadQuery::FilterCallback& value) {
  if (value.is_null()) return false;
  filters_.push_back(value);
  return true;
}

void DownloadQuery::AddFilter(DownloadItem::DownloadState state) {
  AddFilter(base::Bind(&FieldMatches<DownloadItem::DownloadState>, state, EQ,
      base::Bind(&GetState)));
}

void DownloadQuery::AddFilter(DownloadDangerType danger) {
  AddFilter(base::Bind(&FieldMatches<DownloadDangerType>, danger, EQ,
      base::Bind(&GetDangerType)));
}

bool DownloadQuery::AddFilter(DownloadQuery::FilterType type,
                              const base::Value& value) {
  switch (type) {
    case FILTER_BYTES_RECEIVED:
      return AddFilter(BuildFilter<int>(value, EQ, &GetReceivedBytes));
    case FILTER_DANGER_ACCEPTED:
      return AddFilter(BuildFilter<bool>(value, EQ, &GetDangerAccepted));
    case FILTER_EXISTS:
      return AddFilter(BuildFilter<bool>(value, EQ, &GetExists));
    case FILTER_FILENAME:
      return AddFilter(BuildFilter<base::string16>(value, EQ, &GetFilename));
    case FILTER_FILENAME_REGEX:
      return AddFilter(BuildRegexFilter(value, &GetFilenameUTF8));
    case FILTER_MIME:
      return AddFilter(BuildFilter<std::string>(value, EQ, &GetMimeType));
    case FILTER_PAUSED:
      return AddFilter(BuildFilter<bool>(value, EQ, &IsPaused));
    case FILTER_QUERY: {
      std::vector<base::string16> query_terms;
      return GetAs(value, &query_terms) &&
             (query_terms.empty() ||
              AddFilter(base::Bind(&MatchesQuery, query_terms)));
    }
    case FILTER_ENDED_AFTER:
      return AddFilter(BuildFilter<std::string>(value, GT, &GetEndTime));
    case FILTER_ENDED_BEFORE:
      return AddFilter(BuildFilter<std::string>(value, LT, &GetEndTime));
    case FILTER_END_TIME:
      return AddFilter(BuildFilter<std::string>(value, EQ, &GetEndTime));
    case FILTER_STARTED_AFTER:
      return AddFilter(BuildFilter<std::string>(value, GT, &GetStartTime));
    case FILTER_STARTED_BEFORE:
      return AddFilter(BuildFilter<std::string>(value, LT, &GetStartTime));
    case FILTER_START_TIME:
      return AddFilter(BuildFilter<std::string>(value, EQ, &GetStartTime));
    case FILTER_TOTAL_BYTES:
      return AddFilter(BuildFilter<int>(value, EQ, &GetTotalBytes));
    case FILTER_TOTAL_BYTES_GREATER:
      return AddFilter(BuildFilter<int>(value, GT, &GetTotalBytes));
    case FILTER_TOTAL_BYTES_LESS:
      return AddFilter(BuildFilter<int>(value, LT, &GetTotalBytes));
    case FILTER_URL:
      return AddFilter(BuildFilter<std::string>(value, EQ, &GetUrl));
    case FILTER_URL_REGEX:
      return AddFilter(BuildRegexFilter(value, &GetUrl));
  }
  return false;
}

bool DownloadQuery::Matches(const DownloadItem& item) const {
  for (FilterCallbackVector::const_iterator filter = filters_.begin();
        filter != filters_.end(); ++filter) {
    if (!filter->Run(item))
      return false;
  }
  return true;
}

// AddSorter() creates a Sorter and pushes it onto sorters_. A Sorter is a
// direction and a Callback to Compare<>(). After filtering, Search() makes a
// DownloadComparator functor from the sorters_ and passes the
// DownloadComparator to std::partial_sort. std::partial_sort calls the
// DownloadComparator with different pairs of DownloadItems.  DownloadComparator
// iterates over the sorters until a callback returns ComparisonType LT or GT.
// DownloadComparator returns true or false depending on that ComparisonType and
// the sorter's direction in order to indicate to std::partial_sort whether the
// left item is after or before the right item. If all sorters return EQ, then
// DownloadComparator compares GetId. A DownloadQuery may have zero or more
// Sorters, but there is one DownloadComparator per call to Search().

struct DownloadQuery::Sorter {
  typedef base::Callback<ComparisonType(
      const DownloadItem&, const DownloadItem&)> SortType;

  template<typename ValueType>
  static Sorter Build(DownloadQuery::SortDirection adirection,
                         ValueType (*accessor)(const DownloadItem&)) {
    return Sorter(adirection, base::Bind(&Compare<ValueType>,
        base::Bind(accessor)));
  }

  Sorter(DownloadQuery::SortDirection adirection,
            const SortType& asorter)
    : direction(adirection),
      sorter(asorter) {
  }
  ~Sorter() {}

  DownloadQuery::SortDirection direction;
  SortType sorter;
};

class DownloadQuery::DownloadComparator {
 public:
  explicit DownloadComparator(const DownloadQuery::SorterVector& terms)
    : terms_(terms) {
  }

  // Returns true if |left| sorts before |right|.
  bool operator() (const DownloadItem* left, const DownloadItem* right);

 private:
  const DownloadQuery::SorterVector& terms_;

  // std::sort requires this class to be copyable.
};

bool DownloadQuery::DownloadComparator::operator() (
    const DownloadItem* left, const DownloadItem* right) {
  for (DownloadQuery::SorterVector::const_iterator term = terms_.begin();
       term != terms_.end(); ++term) {
    switch (term->sorter.Run(*left, *right)) {
      case LT: return term->direction == DownloadQuery::ASCENDING;
      case GT: return term->direction == DownloadQuery::DESCENDING;
      case EQ: break;  // break the switch but not the loop
    }
  }
  CHECK_NE(left->GetId(), right->GetId());
  return left->GetId() < right->GetId();
}

void DownloadQuery::AddSorter(DownloadQuery::SortType type,
                              DownloadQuery::SortDirection direction) {
  switch (type) {
    case SORT_END_TIME:
      sorters_.push_back(Sorter::Build<int64>(direction, &GetEndTimeMsEpoch));
      break;
    case SORT_START_TIME:
      sorters_.push_back(Sorter::Build<int64>(direction, &GetStartTimeMsEpoch));
      break;
    case SORT_URL:
      sorters_.push_back(Sorter::Build<std::string>(direction, &GetUrl));
      break;
    case SORT_FILENAME:
      sorters_.push_back(
          Sorter::Build<base::string16>(direction, &GetFilename));
      break;
    case SORT_DANGER:
      sorters_.push_back(Sorter::Build<DownloadDangerType>(
          direction, &GetDangerType));
      break;
    case SORT_DANGER_ACCEPTED:
      sorters_.push_back(Sorter::Build<bool>(direction, &GetDangerAccepted));
      break;
    case SORT_EXISTS:
      sorters_.push_back(Sorter::Build<bool>(direction, &GetExists));
      break;
    case SORT_STATE:
      sorters_.push_back(Sorter::Build<DownloadItem::DownloadState>(
          direction, &GetState));
      break;
    case SORT_PAUSED:
      sorters_.push_back(Sorter::Build<bool>(direction, &IsPaused));
      break;
    case SORT_MIME:
      sorters_.push_back(Sorter::Build<std::string>(direction, &GetMimeType));
      break;
    case SORT_BYTES_RECEIVED:
      sorters_.push_back(Sorter::Build<int>(direction, &GetReceivedBytes));
      break;
    case SORT_TOTAL_BYTES:
      sorters_.push_back(Sorter::Build<int>(direction, &GetTotalBytes));
      break;
  }
}

void DownloadQuery::FinishSearch(DownloadQuery::DownloadVector* results) const {
  if (!sorters_.empty())
    std::partial_sort(results->begin(),
                      results->begin() + std::min(limit_, results->size()),
                      results->end(),
                      DownloadComparator(sorters_));
  if (results->size() > limit_)
    results->resize(limit_);
}