Revert of Move base/prefs to components/prefs

components/prefs/json_pref_store.cc

Index: components/prefs/json_pref_store.cc
diff --git a/components/prefs/json_pref_store.cc b/components/prefs/json_pref_store.cc
deleted file mode 100644
index ffc750ed81b8898f5c51865c8dd38ba02b4d6bbb..0000000000000000000000000000000000000000
--- a/components/prefs/json_pref_store.cc
+++ /dev/null
@@ -1,537 +0,0 @@
-// 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 "base/prefs/json_pref_store.h"
-
-#include <stddef.h>
-
-#include <algorithm>
-#include <utility>
-
-#include "base/bind.h"
-#include "base/callback.h"
-#include "base/files/file_path.h"
-#include "base/files/file_util.h"
-#include "base/json/json_file_value_serializer.h"
-#include "base/json/json_string_value_serializer.h"
-#include "base/macros.h"
-#include "base/memory/ref_counted.h"
-#include "base/metrics/histogram.h"
-#include "base/prefs/pref_filter.h"
-#include "base/sequenced_task_runner.h"
-#include "base/strings/string_number_conversions.h"
-#include "base/strings/string_util.h"
-#include "base/task_runner_util.h"
-#include "base/threading/sequenced_worker_pool.h"
-#include "base/time/default_clock.h"
-#include "base/values.h"
-
-// Result returned from internal read tasks.
-struct JsonPrefStore::ReadResult {
- public:
-  ReadResult();
-  ~ReadResult();
-
-  scoped_ptr<base::Value> value;
-  PrefReadError error;
-  bool no_dir;
-
- private:
-  DISALLOW_COPY_AND_ASSIGN(ReadResult);
-};
-
-JsonPrefStore::ReadResult::ReadResult()
-    : error(PersistentPrefStore::PREF_READ_ERROR_NONE), no_dir(false) {
-}
-
-JsonPrefStore::ReadResult::~ReadResult() {
-}
-
-namespace {
-
-// Some extensions we'll tack on to copies of the Preferences files.
-const base::FilePath::CharType kBadExtension[] = FILE_PATH_LITERAL("bad");
-
-PersistentPrefStore::PrefReadError HandleReadErrors(
-    const base::Value* value,
-    const base::FilePath& path,
-    int error_code,
-    const std::string& error_msg) {
-  if (!value) {
-    DVLOG(1) << "Error while loading JSON file: " << error_msg
-             << ", file: " << path.value();
-    switch (error_code) {
-      case JSONFileValueDeserializer::JSON_ACCESS_DENIED:
-        return PersistentPrefStore::PREF_READ_ERROR_ACCESS_DENIED;
-      case JSONFileValueDeserializer::JSON_CANNOT_READ_FILE:
-        return PersistentPrefStore::PREF_READ_ERROR_FILE_OTHER;
-      case JSONFileValueDeserializer::JSON_FILE_LOCKED:
-        return PersistentPrefStore::PREF_READ_ERROR_FILE_LOCKED;
-      case JSONFileValueDeserializer::JSON_NO_SUCH_FILE:
-        return PersistentPrefStore::PREF_READ_ERROR_NO_FILE;
-      default:
-        // JSON errors indicate file corruption of some sort.
-        // Since the file is corrupt, move it to the side and continue with
-        // empty preferences.  This will result in them losing their settings.
-        // We keep the old file for possible support and debugging assistance
-        // as well as to detect if they're seeing these errors repeatedly.
-        // TODO(erikkay) Instead, use the last known good file.
-        base::FilePath bad = path.ReplaceExtension(kBadExtension);
-
-        // If they've ever had a parse error before, put them in another bucket.
-        // TODO(erikkay) if we keep this error checking for very long, we may
-        // want to differentiate between recent and long ago errors.
-        bool bad_existed = base::PathExists(bad);
-        base::Move(path, bad);
-        return bad_existed ? PersistentPrefStore::PREF_READ_ERROR_JSON_REPEAT
-                           : PersistentPrefStore::PREF_READ_ERROR_JSON_PARSE;
-    }
-  }
-  if (!value->IsType(base::Value::TYPE_DICTIONARY))
-    return PersistentPrefStore::PREF_READ_ERROR_JSON_TYPE;
-  return PersistentPrefStore::PREF_READ_ERROR_NONE;
-}
-
-// Records a sample for |size| in the Settings.JsonDataReadSizeKilobytes
-// histogram suffixed with the base name of the JSON file under |path|.
-void RecordJsonDataSizeHistogram(const base::FilePath& path, size_t size) {
-  std::string spaceless_basename;
-  base::ReplaceChars(path.BaseName().MaybeAsASCII(), " ", "_",
-                     &spaceless_basename);
-
-  // The histogram below is an expansion of the UMA_HISTOGRAM_CUSTOM_COUNTS
-  // macro adapted to allow for a dynamically suffixed histogram name.
-  // Note: The factory creates and owns the histogram.
-  base::HistogramBase* histogram = base::Histogram::FactoryGet(
-      "Settings.JsonDataReadSizeKilobytes." + spaceless_basename, 1, 10000, 50,
-      base::HistogramBase::kUmaTargetedHistogramFlag);
-  histogram->Add(static_cast<int>(size) / 1024);
-}
-
-scoped_ptr<JsonPrefStore::ReadResult> ReadPrefsFromDisk(
-    const base::FilePath& path,
-    const base::FilePath& alternate_path) {
-  if (!base::PathExists(path) && !alternate_path.empty() &&
-      base::PathExists(alternate_path)) {
-    base::Move(alternate_path, path);
-  }
-
-  int error_code;
-  std::string error_msg;
-  scoped_ptr<JsonPrefStore::ReadResult> read_result(
-      new JsonPrefStore::ReadResult);
-  JSONFileValueDeserializer deserializer(path);
-  read_result->value = deserializer.Deserialize(&error_code, &error_msg);
-  read_result->error =
-      HandleReadErrors(read_result->value.get(), path, error_code, error_msg);
-  read_result->no_dir = !base::PathExists(path.DirName());
-
-  if (read_result->error == PersistentPrefStore::PREF_READ_ERROR_NONE)
-    RecordJsonDataSizeHistogram(path, deserializer.get_last_read_size());
-
-  return read_result;
-}
-
-}  // namespace
-
-// static
-scoped_refptr<base::SequencedTaskRunner> JsonPrefStore::GetTaskRunnerForFile(
-    const base::FilePath& filename,
-    base::SequencedWorkerPool* worker_pool) {
-  std::string token("json_pref_store-");
-  token.append(filename.AsUTF8Unsafe());
-  return worker_pool->GetSequencedTaskRunnerWithShutdownBehavior(
-      worker_pool->GetNamedSequenceToken(token),
-      base::SequencedWorkerPool::BLOCK_SHUTDOWN);
-}
-
-JsonPrefStore::JsonPrefStore(
-    const base::FilePath& pref_filename,
-    const scoped_refptr<base::SequencedTaskRunner>& sequenced_task_runner,
-    scoped_ptr<PrefFilter> pref_filter)
-    : JsonPrefStore(pref_filename,
-                    base::FilePath(),
-                    sequenced_task_runner,
-                    std::move(pref_filter)) {}
-
-JsonPrefStore::JsonPrefStore(
-    const base::FilePath& pref_filename,
-    const base::FilePath& pref_alternate_filename,
-    const scoped_refptr<base::SequencedTaskRunner>& sequenced_task_runner,
-    scoped_ptr<PrefFilter> pref_filter)
-    : path_(pref_filename),
-      alternate_path_(pref_alternate_filename),
-      sequenced_task_runner_(sequenced_task_runner),
-      prefs_(new base::DictionaryValue()),
-      read_only_(false),
-      writer_(pref_filename, sequenced_task_runner),
-      pref_filter_(std::move(pref_filter)),
-      initialized_(false),
-      filtering_in_progress_(false),
-      pending_lossy_write_(false),
-      read_error_(PREF_READ_ERROR_NONE),
-      write_count_histogram_(writer_.commit_interval(), path_) {
-  DCHECK(!path_.empty());
-}
-
-bool JsonPrefStore::GetValue(const std::string& key,
-                             const base::Value** result) const {
-  DCHECK(CalledOnValidThread());
-
-  base::Value* tmp = nullptr;
-  if (!prefs_->Get(key, &tmp))
-    return false;
-
-  if (result)
-    *result = tmp;
-  return true;
-}
-
-void JsonPrefStore::AddObserver(PrefStore::Observer* observer) {
-  DCHECK(CalledOnValidThread());
-
-  observers_.AddObserver(observer);
-}
-
-void JsonPrefStore::RemoveObserver(PrefStore::Observer* observer) {
-  DCHECK(CalledOnValidThread());
-
-  observers_.RemoveObserver(observer);
-}
-
-bool JsonPrefStore::HasObservers() const {
-  DCHECK(CalledOnValidThread());
-
-  return observers_.might_have_observers();
-}
-
-bool JsonPrefStore::IsInitializationComplete() const {
-  DCHECK(CalledOnValidThread());
-
-  return initialized_;
-}
-
-bool JsonPrefStore::GetMutableValue(const std::string& key,
-                                    base::Value** result) {
-  DCHECK(CalledOnValidThread());
-
-  return prefs_->Get(key, result);
-}
-
-void JsonPrefStore::SetValue(const std::string& key,
-                             scoped_ptr<base::Value> value,
-                             uint32_t flags) {
-  DCHECK(CalledOnValidThread());
-
-  DCHECK(value);
-  base::Value* old_value = nullptr;
-  prefs_->Get(key, &old_value);
-  if (!old_value || !value->Equals(old_value)) {
-    prefs_->Set(key, std::move(value));
-    ReportValueChanged(key, flags);
-  }
-}
-
-void JsonPrefStore::SetValueSilently(const std::string& key,
-                                     scoped_ptr<base::Value> value,
-                                     uint32_t flags) {
-  DCHECK(CalledOnValidThread());
-
-  DCHECK(value);
-  base::Value* old_value = nullptr;
-  prefs_->Get(key, &old_value);
-  if (!old_value || !value->Equals(old_value)) {
-    prefs_->Set(key, std::move(value));
-    ScheduleWrite(flags);
-  }
-}
-
-void JsonPrefStore::RemoveValue(const std::string& key, uint32_t flags) {
-  DCHECK(CalledOnValidThread());
-
-  if (prefs_->RemovePath(key, nullptr))
-    ReportValueChanged(key, flags);
-}
-
-void JsonPrefStore::RemoveValueSilently(const std::string& key,
-                                        uint32_t flags) {
-  DCHECK(CalledOnValidThread());
-
-  prefs_->RemovePath(key, nullptr);
-  ScheduleWrite(flags);
-}
-
-bool JsonPrefStore::ReadOnly() const {
-  DCHECK(CalledOnValidThread());
-
-  return read_only_;
-}
-
-PersistentPrefStore::PrefReadError JsonPrefStore::GetReadError() const {
-  DCHECK(CalledOnValidThread());
-
-  return read_error_;
-}
-
-PersistentPrefStore::PrefReadError JsonPrefStore::ReadPrefs() {
-  DCHECK(CalledOnValidThread());
-
-  OnFileRead(ReadPrefsFromDisk(path_, alternate_path_));
-  return filtering_in_progress_ ? PREF_READ_ERROR_ASYNCHRONOUS_TASK_INCOMPLETE
-                                : read_error_;
-}
-
-void JsonPrefStore::ReadPrefsAsync(ReadErrorDelegate* error_delegate) {
-  DCHECK(CalledOnValidThread());
-
-  initialized_ = false;
-  error_delegate_.reset(error_delegate);
-
-  // Weakly binds the read task so that it doesn't kick in during shutdown.
-  base::PostTaskAndReplyWithResult(
-      sequenced_task_runner_.get(),
-      FROM_HERE,
-      base::Bind(&ReadPrefsFromDisk, path_, alternate_path_),
-      base::Bind(&JsonPrefStore::OnFileRead, AsWeakPtr()));
-}
-
-void JsonPrefStore::CommitPendingWrite() {
-  DCHECK(CalledOnValidThread());
-
-  // Schedule a write for any lossy writes that are outstanding to ensure that
-  // they get flushed when this function is called.
-  SchedulePendingLossyWrites();
-
-  if (writer_.HasPendingWrite() && !read_only_)
-    writer_.DoScheduledWrite();
-}
-
-void JsonPrefStore::SchedulePendingLossyWrites() {
-  if (pending_lossy_write_)
-    writer_.ScheduleWrite(this);
-}
-
-void JsonPrefStore::ReportValueChanged(const std::string& key, uint32_t flags) {
-  DCHECK(CalledOnValidThread());
-
-  if (pref_filter_)
-    pref_filter_->FilterUpdate(key);
-
-  FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key));
-
-  ScheduleWrite(flags);
-}
-
-void JsonPrefStore::RegisterOnNextSuccessfulWriteCallback(
-    const base::Closure& on_next_successful_write) {
-  DCHECK(CalledOnValidThread());
-
-  writer_.RegisterOnNextSuccessfulWriteCallback(on_next_successful_write);
-}
-
-void JsonPrefStore::OnFileRead(scoped_ptr<ReadResult> read_result) {
-  DCHECK(CalledOnValidThread());
-
-  DCHECK(read_result);
-
-  scoped_ptr<base::DictionaryValue> unfiltered_prefs(new base::DictionaryValue);
-
-  read_error_ = read_result->error;
-
-  bool initialization_successful = !read_result->no_dir;
-
-  if (initialization_successful) {
-    switch (read_error_) {
-      case PREF_READ_ERROR_ACCESS_DENIED:
-      case PREF_READ_ERROR_FILE_OTHER:
-      case PREF_READ_ERROR_FILE_LOCKED:
-      case PREF_READ_ERROR_JSON_TYPE:
-      case PREF_READ_ERROR_FILE_NOT_SPECIFIED:
-        read_only_ = true;
-        break;
-      case PREF_READ_ERROR_NONE:
-        DCHECK(read_result->value.get());
-        unfiltered_prefs.reset(
-            static_cast<base::DictionaryValue*>(read_result->value.release()));
-        break;
-      case PREF_READ_ERROR_NO_FILE:
-        // If the file just doesn't exist, maybe this is first run.  In any case
-        // there's no harm in writing out default prefs in this case.
-      case PREF_READ_ERROR_JSON_PARSE:
-      case PREF_READ_ERROR_JSON_REPEAT:
-        break;
-      case PREF_READ_ERROR_ASYNCHRONOUS_TASK_INCOMPLETE:
-        // This is a special error code to be returned by ReadPrefs when it
-        // can't complete synchronously, it should never be returned by the read
-        // operation itself.
-      case PREF_READ_ERROR_MAX_ENUM:
-        NOTREACHED();
-        break;
-    }
-  }
-
-  if (pref_filter_) {
-    filtering_in_progress_ = true;
-    const PrefFilter::PostFilterOnLoadCallback post_filter_on_load_callback(
-        base::Bind(
-            &JsonPrefStore::FinalizeFileRead, AsWeakPtr(),
-            initialization_successful));
-    pref_filter_->FilterOnLoad(post_filter_on_load_callback,
-                               std::move(unfiltered_prefs));
-  } else {
-    FinalizeFileRead(initialization_successful, std::move(unfiltered_prefs),
-                     false);
-  }
-}
-
-JsonPrefStore::~JsonPrefStore() {
-  CommitPendingWrite();
-}
-
-bool JsonPrefStore::SerializeData(std::string* output) {
-  DCHECK(CalledOnValidThread());
-
-  pending_lossy_write_ = false;
-
-  write_count_histogram_.RecordWriteOccured();
-
-  if (pref_filter_)
-    pref_filter_->FilterSerializeData(prefs_.get());
-
-  JSONStringValueSerializer serializer(output);
-  // Not pretty-printing prefs shrinks pref file size by ~30%. To obtain
-  // readable prefs for debugging purposes, you can dump your prefs into any
-  // command-line or online JSON pretty printing tool.
-  serializer.set_pretty_print(false);
-  return serializer.Serialize(*prefs_);
-}
-
-void JsonPrefStore::FinalizeFileRead(bool initialization_successful,
-                                     scoped_ptr<base::DictionaryValue> prefs,
-                                     bool schedule_write) {
-  DCHECK(CalledOnValidThread());
-
-  filtering_in_progress_ = false;
-
-  if (!initialization_successful) {
-    FOR_EACH_OBSERVER(PrefStore::Observer,
-                      observers_,
-                      OnInitializationCompleted(false));
-    return;
-  }
-
-  prefs_ = std::move(prefs);
-
-  initialized_ = true;
-
-  if (schedule_write)
-    ScheduleWrite(DEFAULT_PREF_WRITE_FLAGS);
-
-  if (error_delegate_ && read_error_ != PREF_READ_ERROR_NONE)
-    error_delegate_->OnError(read_error_);
-
-  FOR_EACH_OBSERVER(PrefStore::Observer,
-                    observers_,
-                    OnInitializationCompleted(true));
-
-  return;
-}
-
-void JsonPrefStore::ScheduleWrite(uint32_t flags) {
-  if (read_only_)
-    return;
-
-  if (flags & LOSSY_PREF_WRITE_FLAG)
-    pending_lossy_write_ = true;
-  else
-    writer_.ScheduleWrite(this);
-}
-
-// NOTE: This value should NOT be changed without renaming the histogram
-// otherwise it will create incompatible buckets.
-const int32_t
-    JsonPrefStore::WriteCountHistogram::kHistogramWriteReportIntervalMins = 5;
-
-JsonPrefStore::WriteCountHistogram::WriteCountHistogram(
-    const base::TimeDelta& commit_interval,
-    const base::FilePath& path)
-    : WriteCountHistogram(commit_interval,
-                          path,
-                          scoped_ptr<base::Clock>(new base::DefaultClock)) {
-}
-
-JsonPrefStore::WriteCountHistogram::WriteCountHistogram(
-    const base::TimeDelta& commit_interval,
-    const base::FilePath& path,
-    scoped_ptr<base::Clock> clock)
-    : commit_interval_(commit_interval),
-      path_(path),
-      clock_(clock.release()),
-      report_interval_(
-          base::TimeDelta::FromMinutes(kHistogramWriteReportIntervalMins)),
-      last_report_time_(clock_->Now()),
-      writes_since_last_report_(0) {
-}
-
-JsonPrefStore::WriteCountHistogram::~WriteCountHistogram() {
-  ReportOutstandingWrites();
-}
-
-void JsonPrefStore::WriteCountHistogram::RecordWriteOccured() {
-  ReportOutstandingWrites();
-
-  ++writes_since_last_report_;
-}
-
-void JsonPrefStore::WriteCountHistogram::ReportOutstandingWrites() {
-  base::Time current_time = clock_->Now();
-  base::TimeDelta time_since_last_report = current_time - last_report_time_;
-
-  if (time_since_last_report <= report_interval_)
-    return;
-
-  // If the time since the last report exceeds the report interval, report all
-  // the writes since the last report. They must have all occurred in the same
-  // report interval.
-  base::HistogramBase* histogram = GetHistogram();
-  histogram->Add(writes_since_last_report_);
-
-  // There may be several report intervals that elapsed that don't have any
-  // writes in them. Report these too.
-  int64_t total_num_intervals_elapsed =
-      (time_since_last_report / report_interval_);
-  for (int64_t i = 0; i < total_num_intervals_elapsed - 1; ++i)
-    histogram->Add(0);
-
-  writes_since_last_report_ = 0;
-  last_report_time_ += total_num_intervals_elapsed * report_interval_;
-}
-
-base::HistogramBase* JsonPrefStore::WriteCountHistogram::GetHistogram() {
-  std::string spaceless_basename;
-  base::ReplaceChars(path_.BaseName().MaybeAsASCII(), " ", "_",
-                     &spaceless_basename);
-  std::string histogram_name =
-      "Settings.JsonDataWriteCount." + spaceless_basename;
-
-  // The min value for a histogram is 1. The max value is the maximum number of
-  // writes that can occur in the window being recorded. The number of buckets
-  // used is the max value (plus the underflow/overflow buckets).
-  int32_t min_value = 1;
-  int32_t max_value = report_interval_ / commit_interval_;
-  int32_t num_buckets = max_value + 1;
-
-  // NOTE: These values should NOT be changed without renaming the histogram
-  // otherwise it will create incompatible buckets.
-  DCHECK_EQ(30, max_value);
-  DCHECK_EQ(31, num_buckets);
-
-  // The histogram below is an expansion of the UMA_HISTOGRAM_CUSTOM_COUNTS
-  // macro adapted to allow for a dynamically suffixed histogram name.
-  // Note: The factory creates and owns the histogram.
-  base::HistogramBase* histogram = base::Histogram::FactoryGet(
-      histogram_name, min_value, max_value, num_buckets,
-      base::HistogramBase::kUmaTargetedHistogramFlag);
-  return histogram;
-}