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// Copyright 2014 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 COMPONENTS_METRICS_PERSISTED_LOGS_H_
#define COMPONENTS_METRICS_PERSISTED_LOGS_H_
#include <stddef.h>
#include <memory>
#include <string>
#include <vector>
#include "base/logging.h"
#include "base/macros.h"
#include "base/values.h"
#include "components/metrics/log_store.h"
class PrefService;
namespace metrics {
class PersistedLogsMetrics;
// Maintains a list of unsent logs that are written and restored from disk.
class PersistedLogs : public LogStore {
public:
// Constructs a PersistedLogs that stores data in |local_state| under the
// preference |pref_name|.
// Calling code is responsible for ensuring that the lifetime of |local_state|
// is longer than the lifetime of PersistedLogs.
//
// When saving logs to disk, stores either the first |min_log_count| logs, or
// at least |min_log_bytes| bytes of logs, whichever is greater.
//
// If the optional |max_log_size| parameter is non-zero, all logs larger than
// that limit will be skipped when writing to disk.
PersistedLogs(std::unique_ptr<PersistedLogsMetrics> metrics,
PrefService* local_state,
const char* pref_name,
size_t min_log_count,
size_t min_log_bytes,
size_t max_log_size);
~PersistedLogs();
// LogStore:
bool has_unsent_logs() const override;
bool has_staged_log() const override;
const std::string& staged_log() const override;
const std::string& staged_log_hash() const override;
void StageNextLog() override;
void DiscardStagedLog() override;
void PersistUnsentLogs() const override;
void LoadPersistedUnsentLogs() override;
// Adds a log to the list.
void StoreLog(const std::string& log_data);
// Delete all logs, in memory and on disk.
void Purge();
// Returns the timestamp of the element in the front of the list.
const std::string& staged_log_timestamp() const;
// The number of elements currently stored.
size_t size() const { return list_.size(); }
private:
// Writes the list to the ListValue.
void WriteLogsToPrefList(base::ListValue* list) const;
// Reads the list from the ListValue.
void ReadLogsFromPrefList(const base::ListValue& list);
// An object for recording UMA metrics.
std::unique_ptr<PersistedLogsMetrics> metrics_;
// A weak pointer to the PrefService object to read and write the preference
// from. Calling code should ensure this object continues to exist for the
// lifetime of the PersistedLogs object.
PrefService* local_state_;
// The name of the preference to serialize logs to/from.
const char* pref_name_;
// We will keep at least this |min_log_count_| logs or |min_log_bytes_| bytes
// of logs, whichever is greater, when writing to disk. These apply after
// skipping logs greater than |max_log_size_|.
const size_t min_log_count_;
const size_t min_log_bytes_;
// Logs greater than this size will not be written to disk.
const size_t max_log_size_;
struct LogInfo {
// Initializes the members based on uncompressed |log_data| and
// |log_timestamp|.
// |metrics| is the parent's metrics_ object, and should not be held.
void Init(PersistedLogsMetrics* metrics,
const std::string& log_data,
const std::string& log_timestamp);
// Compressed log data - a serialized protobuf that's been gzipped.
std::string compressed_log_data;
// The SHA1 hash of log, stored to catch errors from memory corruption.
std::string hash;
// The timestamp of when the log was created as a time_t value.
std::string timestamp;
};
// A list of all of the stored logs, stored with SHA1 hashes to check for
// corruption while they are stored in memory.
std::vector<LogInfo> list_;
// The index and type of the log staged for upload. If nothing has been
// staged, the index will be -1.
int staged_log_index_;
DISALLOW_COPY_AND_ASSIGN(PersistedLogs);
};
} // namespace metrics
#endif // COMPONENTS_METRICS_PERSISTED_LOGS_H_
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