| // Copyright (c) 2011 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/common/json_pref_store.h" |
| |
| #include <algorithm> |
| |
| #include "base/bind.h" |
| #include "base/callback.h" |
| #include "base/file_util.h" |
| #include "base/memory/ref_counted.h" |
| #include "base/values.h" |
| #include "content/browser/browser_thread.h" |
| #include "content/common/json_value_serializer.h" |
| |
| namespace { |
| |
| // Some extensions we'll tack on to copies of the Preferences files. |
| const FilePath::CharType* kBadExtension = FILE_PATH_LITERAL("bad"); |
| |
| // Differentiates file loading between UI and FILE threads. |
| class FileThreadDeserializer |
| : public base::RefCountedThreadSafe<FileThreadDeserializer> { |
| public: |
| explicit FileThreadDeserializer(JsonPrefStore* delegate) |
| : delegate_(delegate) { |
| } |
| |
| void Start(const FilePath& path) { |
| DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI)); |
| BrowserThread::PostTask( |
| BrowserThread::FILE, |
| FROM_HERE, |
| NewRunnableMethod(this, |
| &FileThreadDeserializer::ReadFileAndReport, |
| path)); |
| } |
| |
| // Deserializes JSON on the FILE thread. |
| void ReadFileAndReport(const FilePath& path) { |
| DCHECK(BrowserThread::CurrentlyOn(BrowserThread::FILE)); |
| |
| int error_code; |
| std::string error_msg; |
| JSONFileValueSerializer serializer(path); |
| value_.reset(serializer.Deserialize(&error_code, &error_msg)); |
| |
| HandleErrors(value_.get(), path, error_code, error_msg, &error_); |
| |
| no_dir_ = !file_util::PathExists(path.DirName()); |
| |
| BrowserThread::PostTask( |
| BrowserThread::UI, |
| FROM_HERE, |
| NewRunnableMethod(this, &FileThreadDeserializer::ReportOnUIThread)); |
| } |
| |
| // Reports deserialization result on the UI thread. |
| void ReportOnUIThread() { |
| DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI)); |
| delegate_->OnFileRead(value_.release(), error_, no_dir_); |
| } |
| |
| static void HandleErrors(const Value* value, |
| const FilePath& path, |
| int error_code, |
| const std::string& error_msg, |
| PersistentPrefStore::PrefReadError* error); |
| |
| private: |
| friend class base::RefCountedThreadSafe<FileThreadDeserializer>; |
| |
| bool no_dir_; |
| PersistentPrefStore::PrefReadError error_; |
| scoped_ptr<Value> value_; |
| scoped_refptr<JsonPrefStore> delegate_; |
| }; |
| |
| // static |
| void FileThreadDeserializer::HandleErrors( |
| const Value* value, |
| const FilePath& path, |
| int error_code, |
| const std::string& error_msg, |
| PersistentPrefStore::PrefReadError* error) { |
| *error = PersistentPrefStore::PREF_READ_ERROR_NONE; |
| if (!value) { |
| DLOG(ERROR) << "Error while loading JSON file: " << error_msg; |
| switch (error_code) { |
| case JSONFileValueSerializer::JSON_ACCESS_DENIED: |
| *error = PersistentPrefStore::PREF_READ_ERROR_ACCESS_DENIED; |
| break; |
| case JSONFileValueSerializer::JSON_CANNOT_READ_FILE: |
| *error = PersistentPrefStore::PREF_READ_ERROR_FILE_OTHER; |
| break; |
| case JSONFileValueSerializer::JSON_FILE_LOCKED: |
| *error = PersistentPrefStore::PREF_READ_ERROR_FILE_LOCKED; |
| break; |
| case JSONFileValueSerializer::JSON_NO_SUCH_FILE: |
| *error = PersistentPrefStore::PREF_READ_ERROR_NO_FILE; |
| break; |
| default: |
| *error = PersistentPrefStore::PREF_READ_ERROR_JSON_PARSE; |
| // 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. |
| 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. |
| if (file_util::PathExists(bad)) |
| *error = PersistentPrefStore::PREF_READ_ERROR_JSON_REPEAT; |
| file_util::Move(path, bad); |
| break; |
| } |
| } else if (!value->IsType(Value::TYPE_DICTIONARY)) { |
| *error = PersistentPrefStore::PREF_READ_ERROR_JSON_TYPE; |
| } |
| } |
| |
| } // namespace |
| |
| JsonPrefStore::JsonPrefStore(const FilePath& filename, |
| base::MessageLoopProxy* file_message_loop_proxy) |
| : path_(filename), |
| prefs_(new DictionaryValue()), |
| read_only_(false), |
| writer_(filename, file_message_loop_proxy) { |
| } |
| |
| JsonPrefStore::~JsonPrefStore() { |
| CommitPendingWrite(); |
| } |
| |
| PrefStore::ReadResult JsonPrefStore::GetValue(const std::string& key, |
| const Value** result) const { |
| Value* tmp = NULL; |
| if (prefs_->Get(key, &tmp)) { |
| *result = tmp; |
| return READ_OK; |
| } |
| return READ_NO_VALUE; |
| } |
| |
| void JsonPrefStore::AddObserver(PrefStore::Observer* observer) { |
| observers_.AddObserver(observer); |
| } |
| |
| void JsonPrefStore::RemoveObserver(PrefStore::Observer* observer) { |
| observers_.RemoveObserver(observer); |
| } |
| |
| PrefStore::ReadResult JsonPrefStore::GetMutableValue(const std::string& key, |
| Value** result) { |
| return prefs_->Get(key, result) ? READ_OK : READ_NO_VALUE; |
| } |
| |
| void JsonPrefStore::SetValue(const std::string& key, Value* value) { |
| DCHECK(value); |
| scoped_ptr<Value> new_value(value); |
| Value* old_value = NULL; |
| prefs_->Get(key, &old_value); |
| if (!old_value || !value->Equals(old_value)) { |
| prefs_->Set(key, new_value.release()); |
| FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key)); |
| } |
| } |
| |
| void JsonPrefStore::SetValueSilently(const std::string& key, Value* value) { |
| DCHECK(value); |
| scoped_ptr<Value> new_value(value); |
| Value* old_value = NULL; |
| prefs_->Get(key, &old_value); |
| if (!old_value || !value->Equals(old_value)) |
| prefs_->Set(key, new_value.release()); |
| } |
| |
| void JsonPrefStore::RemoveValue(const std::string& key) { |
| if (prefs_->Remove(key, NULL)) { |
| FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key)); |
| } |
| } |
| |
| bool JsonPrefStore::ReadOnly() const { |
| return read_only_; |
| } |
| |
| void JsonPrefStore::OnFileRead(Value* value_owned, |
| PersistentPrefStore::PrefReadError error, |
| bool no_dir) { |
| scoped_ptr<Value> value(value_owned); |
| switch (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: |
| read_only_ = true; |
| break; |
| case PREF_READ_ERROR_NONE: |
| DCHECK(value.get()); |
| prefs_.reset(static_cast<DictionaryValue*>(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. |
| break; |
| case PREF_READ_ERROR_JSON_PARSE: |
| case PREF_READ_ERROR_JSON_REPEAT: |
| break; |
| default: |
| NOTREACHED() << "Unknown error: " << error; |
| } |
| |
| if (delegate_) |
| delegate_->OnPrefsRead(error, no_dir); |
| } |
| |
| void JsonPrefStore::ReadPrefs(Delegate* delegate) { |
| DCHECK(delegate); |
| delegate_ = delegate; |
| |
| if (path_.empty()) { |
| read_only_ = true; |
| delegate_->OnPrefsRead(PREF_READ_ERROR_FILE_NOT_SPECIFIED, false); |
| return; |
| } |
| |
| // This guarantees that class will not be deleted while JSON is readed. |
| DCHECK(BrowserThread::CurrentlyOn(BrowserThread::UI)); |
| |
| // Start async reading of the preferences file. It will delete itself |
| // in the end. |
| scoped_refptr<FileThreadDeserializer> deserializer( |
| new FileThreadDeserializer(this)); |
| deserializer->Start(path_); |
| } |
| |
| PersistentPrefStore::PrefReadError JsonPrefStore::ReadPrefs() { |
| delegate_ = NULL; |
| |
| if (path_.empty()) { |
| read_only_ = true; |
| return PREF_READ_ERROR_FILE_NOT_SPECIFIED; |
| } |
| |
| int error_code = 0; |
| std::string error_msg; |
| |
| JSONFileValueSerializer serializer(path_); |
| scoped_ptr<Value> value(serializer.Deserialize(&error_code, &error_msg)); |
| |
| PersistentPrefStore::PrefReadError error; |
| FileThreadDeserializer::HandleErrors(value.get(), |
| path_, |
| error_code, |
| error_msg, |
| &error); |
| |
| OnFileRead(value.release(), error, false); |
| |
| return error; |
| } |
| |
| bool JsonPrefStore::WritePrefs() { |
| std::string data; |
| if (!SerializeData(&data)) |
| return false; |
| |
| // Lie about our ability to save. |
| if (read_only_) |
| return true; |
| |
| writer_.WriteNow(data); |
| return true; |
| } |
| |
| void JsonPrefStore::ScheduleWritePrefs() { |
| if (read_only_) |
| return; |
| |
| writer_.ScheduleWrite(this); |
| } |
| |
| void JsonPrefStore::CommitPendingWrite() { |
| if (writer_.HasPendingWrite() && !read_only_) |
| writer_.DoScheduledWrite(); |
| } |
| |
| void JsonPrefStore::ReportValueChanged(const std::string& key) { |
| FOR_EACH_OBSERVER(PrefStore::Observer, observers_, OnPrefValueChanged(key)); |
| } |
| |
| bool JsonPrefStore::SerializeData(std::string* output) { |
| // TODO(tc): Do we want to prune webkit preferences that match the default |
| // value? |
| JSONStringValueSerializer serializer(output); |
| serializer.set_pretty_print(true); |
| scoped_ptr<DictionaryValue> copy(prefs_->DeepCopyWithoutEmptyChildren()); |
| return serializer.Serialize(*(copy.get())); |
| } |