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// 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/spellchecker/spellcheck_custom_dictionary.h"
#include <stddef.h>
#include <algorithm>
#include <functional>
#include <utility>
#include <vector>
#include "base/bind.h"
#include "base/containers/contains.h"
#include "base/files/file_util.h"
#include "base/files/important_file_writer.h"
#include "base/hash/md5.h"
#include "base/stl_util.h"
#include "base/strings/string_number_conversions.h"
#include "base/strings/string_split.h"
#include "base/strings/string_util.h"
#include "base/task/post_task.h"
#include "base/task/task_runner_util.h"
#include "base/task/thread_pool.h"
#include "base/threading/scoped_blocking_call.h"
#include "chrome/common/chrome_constants.h"
#include "components/spellcheck/browser/spellcheck_host_metrics.h"
#include "components/spellcheck/common/spellcheck_common.h"
#include "components/sync/model/sync_change.h"
#include "components/sync/model/sync_change_processor.h"
#include "components/sync/model/sync_error_factory.h"
#include "components/sync/protocol/dictionary_specifics.pb.h"
#include "components/sync/protocol/entity_specifics.pb.h"
#include "content/public/browser/browser_task_traits.h"
#include "content/public/browser/browser_thread.h"
using content::BrowserThread;
namespace {
// Filename extension for backup dictionary file.
const base::FilePath::CharType BACKUP_EXTENSION[] = FILE_PATH_LITERAL("backup");
// Prefix for the checksum in the dictionary file.
const char CHECKSUM_PREFIX[] = "checksum_v1 = ";
// The status of the checksum in a custom spellcheck dictionary.
enum ChecksumStatus {
VALID_CHECKSUM,
INVALID_CHECKSUM,
};
// The result of a dictionary sanitation. Can be used as a bitmap.
enum ChangeSanitationResult {
// The change is valid and can be applied as-is.
VALID_CHANGE = 0,
// The change contained words to be added that are not valid.
DETECTED_INVALID_WORDS = 1,
// The change contained words to be added that are already in the dictionary.
DETECTED_DUPLICATE_WORDS = 2,
// The change contained words to be removed that are not in the dictionary.
DETECTED_MISSING_WORDS = 4,
};
// Loads the file at |file_path| into the |words| container. If the file has a
// valid checksum, then returns ChecksumStatus::VALID. If the file has an
// invalid checksum, then returns ChecksumStatus::INVALID and clears |words|.
ChecksumStatus LoadFile(const base::FilePath& file_path,
std::set<std::string>* words) {
DCHECK(words);
words->clear();
std::string contents;
{
base::ScopedBlockingCall scoped_blocking_call(
FROM_HERE, base::BlockingType::MAY_BLOCK);
base::ReadFileToString(file_path, &contents);
}
size_t pos = contents.rfind(CHECKSUM_PREFIX);
if (pos != std::string::npos) {
std::string checksum = contents.substr(pos + strlen(CHECKSUM_PREFIX));
contents = contents.substr(0, pos);
if (checksum != base::MD5String(contents))
return INVALID_CHECKSUM;
}
std::vector<std::string> word_list = base::SplitString(
base::TrimWhitespaceASCII(contents, base::TRIM_ALL), "\n",
base::TRIM_WHITESPACE, base::SPLIT_WANT_ALL);
words->insert(word_list.begin(), word_list.end());
return VALID_CHECKSUM;
}
// Returns true for valid custom dictionary words.
bool IsValidWord(const std::string& word) {
std::string tmp;
return !word.empty() &&
word.size() <= spellcheck::kMaxCustomDictionaryWordBytes &&
base::IsStringUTF8(word) &&
base::TRIM_NONE ==
base::TrimWhitespaceASCII(word, base::TRIM_ALL, &tmp);
}
// Removes duplicate and invalid words from |to_add| word list. Looks for
// duplicates in both |to_add| and |existing| word lists. Returns a bitmap of
// |ChangeSanitationResult| values.
int SanitizeWordsToAdd(const std::set<std::string>& existing,
std::set<std::string>* to_add) {
DCHECK(to_add);
// Do not add duplicate words.
std::vector<std::string> new_words =
base::STLSetDifference<std::vector<std::string>>(*to_add, existing);
int result = VALID_CHANGE;
if (to_add->size() != new_words.size())
result |= DETECTED_DUPLICATE_WORDS;
// Do not add invalid words.
std::set<std::string> valid_new_words;
for (const auto& word : new_words) {
if (IsValidWord(word))
valid_new_words.insert(valid_new_words.end(), word);
}
if (valid_new_words.size() != new_words.size())
result |= DETECTED_INVALID_WORDS;
// Save the sanitized words to be added.
std::swap(*to_add, valid_new_words);
return result;
}
// Loads and returns the custom spellcheck dictionary from |path|. Must be
// called on the file thread.
std::unique_ptr<SpellcheckCustomDictionary::LoadFileResult>
LoadDictionaryFileReliably(const base::FilePath& path) {
// Load the contents and verify the checksum.
std::unique_ptr<SpellcheckCustomDictionary::LoadFileResult> result(
new SpellcheckCustomDictionary::LoadFileResult);
if (LoadFile(path, &result->words) == VALID_CHECKSUM) {
result->is_valid_file =
VALID_CHANGE ==
SanitizeWordsToAdd(std::set<std::string>(), &result->words);
return result;
}
// Checksum is not valid. See if there's a backup.
base::FilePath backup = path.AddExtension(BACKUP_EXTENSION);
if (base::PathExists(backup))
LoadFile(backup, &result->words);
SanitizeWordsToAdd(std::set<std::string>(), &result->words);
return result;
}
// Backs up the original dictionary, saves |custom_words| and its checksum into
// the custom spellcheck dictionary at |path|.
void SaveDictionaryFileReliably(const base::FilePath& path,
const std::set<std::string>& custom_words) {
std::stringstream content;
for (const std::string& word : custom_words)
content << word << '\n';
std::string checksum = base::MD5String(content.str());
content << CHECKSUM_PREFIX << checksum;
{
base::ScopedBlockingCall scoped_blocking_call(
FROM_HERE, base::BlockingType::MAY_BLOCK);
base::FilePath backup_path = path.AddExtension(BACKUP_EXTENSION);
if (!custom_words.empty()) {
base::CopyFile(path, backup_path);
} else {
// The wordlist was just cleared, clean up the .backup file for privacy
// reasons.
base::DeleteFile(backup_path);
}
base::ImportantFileWriter::WriteFileAtomically(path, content.str());
}
}
void SavePassedWordsToDictionaryFileReliably(
const base::FilePath& path,
std::unique_ptr<SpellcheckCustomDictionary::LoadFileResult>
load_file_result) {
DCHECK(load_file_result);
SaveDictionaryFileReliably(path, load_file_result->words);
}
// Removes word from |to_remove| that are missing from |existing| word list and
// sorts |to_remove|. Returns a bitmap of |ChangeSanitationResult| values.
int SanitizeWordsToRemove(const std::set<std::string>& existing,
std::set<std::string>* to_remove) {
DCHECK(to_remove);
// Do not remove words that are missing from the dictionary.
std::set<std::string> found_words =
base::STLSetIntersection<std::set<std::string>>(existing, *to_remove);
int result = VALID_CHANGE;
if (to_remove->size() > found_words.size())
result |= DETECTED_MISSING_WORDS;
// Save the sanitized words to be removed.
std::swap(*to_remove, found_words);
return result;
}
} // namespace
SpellcheckCustomDictionary::Change::Change() {
}
SpellcheckCustomDictionary::Change::~Change() {
}
void SpellcheckCustomDictionary::Change::AddWord(const std::string& word) {
to_add_.insert(word);
}
void SpellcheckCustomDictionary::Change::AddWords(
const std::set<std::string>& words) {
to_add_.insert(words.begin(), words.end());
}
void SpellcheckCustomDictionary::Change::RemoveWord(const std::string& word) {
to_remove_.insert(word);
}
void SpellcheckCustomDictionary::Change::Clear() {
clear_ = true;
}
int SpellcheckCustomDictionary::Change::Sanitize(
const std::set<std::string>& words) {
int result = VALID_CHANGE;
if (!to_add_.empty())
result |= SanitizeWordsToAdd(words, &to_add_);
if (!to_remove_.empty())
result |= SanitizeWordsToRemove(words, &to_remove_);
return result;
}
SpellcheckCustomDictionary::SpellcheckCustomDictionary(
const base::FilePath& dictionary_directory_name)
: task_runner_(
base::ThreadPool::CreateSequencedTaskRunner({base::MayBlock()})),
custom_dictionary_path_(
dictionary_directory_name.Append(chrome::kCustomDictionaryFileName)),
is_loaded_(false) {}
SpellcheckCustomDictionary::~SpellcheckCustomDictionary() {
}
const std::set<std::string>& SpellcheckCustomDictionary::GetWords() const {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
return words_;
}
bool SpellcheckCustomDictionary::AddWord(const std::string& word) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
std::unique_ptr<Change> dictionary_change(new Change);
dictionary_change->AddWord(word);
int result = dictionary_change->Sanitize(GetWords());
Apply(*dictionary_change);
Notify(*dictionary_change);
Sync(*dictionary_change);
Save(std::move(dictionary_change));
return result == VALID_CHANGE;
}
bool SpellcheckCustomDictionary::RemoveWord(const std::string& word) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
std::unique_ptr<Change> dictionary_change(new Change);
dictionary_change->RemoveWord(word);
int result = dictionary_change->Sanitize(GetWords());
Apply(*dictionary_change);
Notify(*dictionary_change);
Sync(*dictionary_change);
Save(std::move(dictionary_change));
return result == VALID_CHANGE;
}
bool SpellcheckCustomDictionary::HasWord(const std::string& word) const {
return base::Contains(words_, word);
}
void SpellcheckCustomDictionary::Clear() {
std::unique_ptr<Change> dictionary_change(new Change);
dictionary_change->Clear();
Apply(*dictionary_change);
Notify(*dictionary_change);
Save(std::move(dictionary_change));
}
void SpellcheckCustomDictionary::AddObserver(Observer* observer) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
DCHECK(observer);
observers_.AddObserver(observer);
}
void SpellcheckCustomDictionary::RemoveObserver(Observer* observer) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
DCHECK(observer);
observers_.RemoveObserver(observer);
}
bool SpellcheckCustomDictionary::IsLoaded() {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
return is_loaded_;
}
bool SpellcheckCustomDictionary::IsSyncing() {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
return !!sync_processor_.get();
}
void SpellcheckCustomDictionary::Load() {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
base::PostTaskAndReplyWithResult(
task_runner_.get(), FROM_HERE,
base::BindOnce(&SpellcheckCustomDictionary::LoadDictionaryFile,
custom_dictionary_path_),
base::BindOnce(&SpellcheckCustomDictionary::OnLoaded,
weak_ptr_factory_.GetWeakPtr()));
}
void SpellcheckCustomDictionary::WaitUntilReadyToSync(base::OnceClosure done) {
DCHECK(!wait_until_ready_to_sync_cb_);
if (is_loaded_)
std::move(done).Run();
else
wait_until_ready_to_sync_cb_ = std::move(done);
}
absl::optional<syncer::ModelError>
SpellcheckCustomDictionary::MergeDataAndStartSyncing(
syncer::ModelType type,
const syncer::SyncDataList& initial_sync_data,
std::unique_ptr<syncer::SyncChangeProcessor> sync_processor,
std::unique_ptr<syncer::SyncErrorFactory> sync_error_handler) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
DCHECK(!sync_processor_.get());
DCHECK(!sync_error_handler_.get());
DCHECK(sync_processor.get());
DCHECK(sync_error_handler.get());
DCHECK_EQ(syncer::DICTIONARY, type);
sync_processor_ = std::move(sync_processor);
sync_error_handler_ = std::move(sync_error_handler);
// Build a list of words to add locally.
std::unique_ptr<Change> to_change_locally(new Change);
for (const syncer::SyncData& data : initial_sync_data) {
DCHECK_EQ(syncer::DICTIONARY, data.GetDataType());
to_change_locally->AddWord(data.GetSpecifics().dictionary().word());
}
// Add as many as possible local words remotely.
to_change_locally->Sanitize(GetWords());
Change to_change_remotely;
to_change_remotely.AddWords(base::STLSetDifference<std::set<std::string>>(
words_, to_change_locally->to_add()));
// Add remote words locally.
Apply(*to_change_locally);
Notify(*to_change_locally);
Save(std::move(to_change_locally));
return Sync(to_change_remotely);
}
void SpellcheckCustomDictionary::StopSyncing(syncer::ModelType type) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
DCHECK_EQ(syncer::DICTIONARY, type);
sync_processor_.reset();
sync_error_handler_.reset();
}
syncer::SyncDataList SpellcheckCustomDictionary::GetAllSyncDataForTesting(
syncer::ModelType type) const {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
DCHECK_EQ(syncer::DICTIONARY, type);
syncer::SyncDataList data;
size_t i = 0;
for (const auto& word : words_) {
if (i++ >= spellcheck::kMaxSyncableDictionaryWords)
break;
sync_pb::EntitySpecifics specifics;
specifics.mutable_dictionary()->set_word(word);
data.push_back(syncer::SyncData::CreateLocalData(word, word, specifics));
}
return data;
}
absl::optional<syncer::ModelError>
SpellcheckCustomDictionary::ProcessSyncChanges(
const base::Location& from_here,
const syncer::SyncChangeList& change_list) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
std::unique_ptr<Change> dictionary_change(new Change);
for (const syncer::SyncChange& change : change_list) {
DCHECK(change.IsValid());
const std::string& word =
change.sync_data().GetSpecifics().dictionary().word();
switch (change.change_type()) {
case syncer::SyncChange::ACTION_ADD:
dictionary_change->AddWord(word);
break;
case syncer::SyncChange::ACTION_DELETE:
dictionary_change->RemoveWord(word);
break;
case syncer::SyncChange::ACTION_UPDATE:
return syncer::ConvertToModelError(
sync_error_handler_->CreateAndUploadError(
FROM_HERE, "Processing sync changes failed on change type " +
syncer::SyncChange::ChangeTypeToString(
change.change_type())));
}
}
dictionary_change->Sanitize(GetWords());
Apply(*dictionary_change);
Notify(*dictionary_change);
Save(std::move(dictionary_change));
return absl::nullopt;
}
SpellcheckCustomDictionary::LoadFileResult::LoadFileResult()
: is_valid_file(false) {}
SpellcheckCustomDictionary::LoadFileResult::~LoadFileResult() {}
// static
std::unique_ptr<SpellcheckCustomDictionary::LoadFileResult>
SpellcheckCustomDictionary::LoadDictionaryFile(const base::FilePath& path) {
std::unique_ptr<LoadFileResult> result = LoadDictionaryFileReliably(path);
SpellCheckHostMetrics::RecordCustomWordCountStats(result->words.size());
return result;
}
// static
void SpellcheckCustomDictionary::UpdateDictionaryFile(
std::unique_ptr<Change> dictionary_change,
const base::FilePath& path) {
DCHECK(dictionary_change);
if (dictionary_change->empty())
return;
std::unique_ptr<LoadFileResult> result = LoadDictionaryFileReliably(path);
// Clear.
if (dictionary_change->clear())
result->words.clear();
// Add words.
result->words.insert(dictionary_change->to_add().begin(),
dictionary_change->to_add().end());
// Remove words and save the remainder.
SaveDictionaryFileReliably(
path, base::STLSetDifference<std::set<std::string>>(
result->words, dictionary_change->to_remove()));
}
void SpellcheckCustomDictionary::OnLoaded(
std::unique_ptr<LoadFileResult> result) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
DCHECK(result);
Change dictionary_change;
dictionary_change.AddWords(result->words);
dictionary_change.Sanitize(GetWords());
Apply(dictionary_change);
Sync(dictionary_change);
is_loaded_ = true;
if (wait_until_ready_to_sync_cb_)
std::move(wait_until_ready_to_sync_cb_).Run();
for (Observer& observer : observers_)
observer.OnCustomDictionaryLoaded();
if (!result->is_valid_file) {
// Save cleaned up data only after startup.
fix_invalid_file_.Reset(
base::BindOnce(&SpellcheckCustomDictionary::FixInvalidFile,
weak_ptr_factory_.GetWeakPtr(), std::move(result)));
content::GetUIThreadTaskRunner({base::TaskPriority::BEST_EFFORT})
->PostTask(FROM_HERE, fix_invalid_file_.callback());
}
}
void SpellcheckCustomDictionary::Apply(const Change& dictionary_change) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
if (dictionary_change.clear())
words_.clear();
if (!dictionary_change.to_add().empty()) {
words_.insert(dictionary_change.to_add().begin(),
dictionary_change.to_add().end());
}
for (const auto& word : dictionary_change.to_remove())
words_.erase(word);
}
void SpellcheckCustomDictionary::FixInvalidFile(
std::unique_ptr<LoadFileResult> load_file_result) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
task_runner_->PostTask(
FROM_HERE,
base::BindOnce(&SavePassedWordsToDictionaryFileReliably,
custom_dictionary_path_, std::move(load_file_result)));
}
void SpellcheckCustomDictionary::Save(
std::unique_ptr<Change> dictionary_change) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
fix_invalid_file_.Cancel();
task_runner_->PostTask(
FROM_HERE,
base::BindOnce(&SpellcheckCustomDictionary::UpdateDictionaryFile,
std::move(dictionary_change), custom_dictionary_path_));
}
absl::optional<syncer::ModelError> SpellcheckCustomDictionary::Sync(
const Change& dictionary_change) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
if (!IsSyncing() || dictionary_change.empty())
return absl::nullopt;
// The number of words on the sync server should not exceed the limits.
int server_size = static_cast<int>(words_.size()) -
static_cast<int>(dictionary_change.to_add().size());
int max_upload_size =
std::max(0, static_cast<int>(spellcheck::kMaxSyncableDictionaryWords) -
server_size);
int upload_size = std::min(
static_cast<int>(dictionary_change.to_add().size()),
max_upload_size);
syncer::SyncChangeList sync_change_list;
int i = 0;
for (const auto& word : dictionary_change.to_add()) {
if (i++ >= upload_size)
break;
sync_pb::EntitySpecifics specifics;
specifics.mutable_dictionary()->set_word(word);
sync_change_list.push_back(syncer::SyncChange(
FROM_HERE, syncer::SyncChange::ACTION_ADD,
syncer::SyncData::CreateLocalData(word, word, specifics)));
}
for (const std::string& word : dictionary_change.to_remove()) {
sync_pb::EntitySpecifics specifics;
specifics.mutable_dictionary()->set_word(word);
sync_change_list.push_back(syncer::SyncChange(
FROM_HERE,
syncer::SyncChange::ACTION_DELETE,
syncer::SyncData::CreateLocalData(word, word, specifics)));
}
// Send the changes to the sync processor.
absl::optional<syncer::ModelError> error =
sync_processor_->ProcessSyncChanges(FROM_HERE, sync_change_list);
if (error.has_value())
return error;
// Turn off syncing of this dictionary if the server already has the maximum
// number of words.
if (words_.size() > spellcheck::kMaxSyncableDictionaryWords)
StopSyncing(syncer::DICTIONARY);
return absl::nullopt;
}
void SpellcheckCustomDictionary::Notify(const Change& dictionary_change) {
DCHECK_CURRENTLY_ON(BrowserThread::UI);
if (!IsLoaded() || dictionary_change.empty())
return;
for (Observer& observer : observers_)
observer.OnCustomDictionaryChanged(dictionary_change);
}
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