cmds/statsd/src/LogReader.h

/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#ifndef LOGREADER_H
#define LOGREADER_H

#include <log/log_read.h>
#include <utils/RefBase.h>

#include <vector>

namespace android {
namespace os {
namespace statsd {

/**
 * Callback for LogReader
 */
class LogListener : public virtual android::RefBase {
public:
    LogListener();
    virtual ~LogListener();

    // TODO: Rather than using log_msg, which doesn't have any real internal structure
    // here, we should pull this out into our own LogEntry class.
    virtual void OnLogEvent(const log_msg& msg) = 0;
};

/**
 * Class to read logs from logd.
 */
class LogReader : public virtual android::RefBase {
public:
    /**
     * Construct the LogReader with a pointer back to the StatsService
     */
    LogReader();

    /**
     * Destructor.
     */
    virtual ~LogReader();

    /**
     * Add a LogListener class.
     */
    void AddListener(const android::sp<LogListener>& listener);

    /**
     * Run the main LogReader loop
     */
    void Run();

private:
    /**
     * List of listeners to call back on when we do get an event.
     */
    std::vector<android::sp<LogListener> > m_listeners;

    /**
     * Connect to a single instance of logd, and read until there's a read error.
     * Logd can crash, exit, be killed etc.
     *
     * Returns the number of lines that were read.
     */
    int connect_and_read();
};

}  // namespace statsd
}  // namespace os
}  // namespace android

#endif  // LOGREADER_H