cmds/statsd/src/logd/LogEvent.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.
 */

#pragma once

#include "field_util.h"
#include "frameworks/base/cmds/statsd/src/stats_log.pb.h"

#include <android/util/ProtoOutputStream.h>
#include <log/log_event_list.h>
#include <log/log_read.h>
#include <private/android_logger.h>
#include <utils/Errors.h>
#include <utils/JenkinsHash.h>

#include <memory>
#include <string>
#include <map>
#include <vector>

namespace android {
namespace os {
namespace statsd {

using std::string;
using std::vector;

/**
 * Wrapper for the log_msg structure.
 */
class LogEvent {
public:
    /**
     * Read a LogEvent from a log_msg.
     */
    explicit LogEvent(log_msg& msg);

    /**
     * Constructs a LogEvent with synthetic data for testing. Must call init() before reading.
     */
    explicit LogEvent(int32_t tagId, uint64_t timestampNs);

    ~LogEvent();

    /**
     * Get the timestamp associated with this event.
     */
    uint64_t GetTimestampNs() const { return mTimestampNs; }

    /**
     * Get the tag for this event.
     */
    int GetTagId() const { return mTagId; }

    uint32_t GetUid() const {
        return mLogUid;
    }

    /**
     * Get the nth value, starting at 1.
     *
     * Returns BAD_INDEX if the index is larger than the number of elements.
     * Returns BAD_TYPE if the index is available but the data is the wrong type.
     */
    int64_t GetLong(size_t key, status_t* err) const;
    const char* GetString(size_t key, status_t* err) const;
    bool GetBool(size_t key, status_t* err) const;
    float GetFloat(size_t key, status_t* err) const;

    /*
     * Get DimensionsValue proto objects from FieldMatcher.
     */
    void GetAtomDimensionsValueProtos(
        const FieldMatcher& matcher, std::vector<DimensionsValue> *dimensionsValues) const;
    bool GetAtomDimensionsValueProto(
        const FieldMatcher& matcher, DimensionsValue* dimensionsValue) const;

    /*
     * Get a DimensionsValue proto objects from Field.
     */
    bool GetSimpleAtomDimensionsValueProto(size_t field, DimensionsValue* dimensionsValue) const;
    DimensionsValue  GetSimpleAtomDimensionsValueProto(size_t atomField)  const;

    /**
     * Write test data to the LogEvent. This can only be used when the LogEvent is constructed
     * using LogEvent(tagId, timestampNs). You need to call init() before you can read from it.
     */
    bool write(uint32_t value);
    bool write(int32_t value);
    bool write(uint64_t value);
    bool write(int64_t value);
    bool write(const string& value);
    bool write(float value);
    bool write(const std::vector<AttributionNode>& nodes);
    bool write(const AttributionNode& node);

    /**
     * Return a string representation of this event.
     */
    string ToString() const;

    /**
     * Write this object to a ProtoOutputStream.
     */
    void ToProto(android::util::ProtoOutputStream& out) const;

    /**
     * Used with the constructor where tag is passed in. Converts the log_event_list to read mode
     * and prepares the list for reading.
     */
    void init();

    /**
     * Set timestamp if the original timestamp is missing.
     */
    void setTimestampNs(uint64_t timestampNs) {mTimestampNs = timestampNs;}

    inline int size() const {
        return mFieldValueMap.size();
    }

    /**
     * Returns the mutable DimensionsValue proto for the specific the field.
     */
    DimensionsValue* findFieldValueOrNull(const Field& field);

    inline const FieldValueMap& getFieldValueMap() const { return mFieldValueMap; }

private:
    /**
     * Don't copy, it's slower. If we really need this we can add it but let's try to
     * avoid it.
     */
    explicit LogEvent(const LogEvent&);

    /**
     * Parses a log_msg into a LogEvent object.
     */
    void init(android_log_context context);

    FieldValueMap mFieldValueMap;

    // This field is used when statsD wants to create log event object and write fields to it. After
    // calling init() function, this object would be destroyed to save memory usage.
    // When the log event is created from log msg, this field is never initiated.
    android_log_context mContext;

    uint64_t mTimestampNs;

    int mTagId;

    uint32_t mLogUid;
};

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