Merge pull request #638 from Susurrus/logging_compress

QGC data logging now records small MAVLink messages.

src/comm/MAVLinkProtocol.cc

@@ -16,6 +16,7 @@
 #include <QMessageBox>
 #include <QSettings>
 #include <QDesktopServices>
+#include <QtEndian>
 
 #include "MAVLinkProtocol.h"
 #include "UASInterface.h"
@@ -358,19 +359,26 @@ void MAVLinkProtocol::receiveBytes(LinkInterface* link, QByteArray b)
             // Log data
             if (m_loggingEnabled && m_logfile)
             {
-                uint8_t buf[MAVLINK_MAX_PACKET_LEN+sizeof(quint64)] = {0};
-                quint64 time = QGC::groundTimeUsecs();
-                memcpy(buf, (void*)&time, sizeof(quint64));
-                // Write message to buffer
-                mavlink_msg_to_send_buffer(buf+sizeof(quint64), &message);
-                //we need to write the maximum package length for having a
-                //consistent file structure and beeing able to parse it again
-                int len = MAVLINK_MAX_PACKET_LEN + sizeof(quint64);
+                uint8_t buf[MAVLINK_MAX_PACKET_LEN+sizeof(quint64)];
+
+                // Write the uint64 time in microseconds in big endian format before the message.
+                // This timestamp is saved in UTC time. We are only saving in ms precision because
+                // getting more than this isn't possible with Qt without a ton of extra code.
+                quint64 time = (quint64)QDateTime::currentMSecsSinceEpoch() * 1000;
+                qToBigEndian(time, buf);
+
+                // Then write the message to the buffer
+                int len = mavlink_msg_to_send_buffer(buf + sizeof(quint64), &message);
+
+                // Determine how many bytes were written by adding the timestamp size to the message size
+                len += sizeof(quint64);
+
+                // Now write this timestamp/message pair to the log.
                 QByteArray b((const char*)buf, len);
                 if(m_logfile->write(b) != len)
                 {
+                    // If there's an error logging data, raise an alert and stop logging.
                     emit protocolStatusMessage(tr("MAVLink Logging failed"), tr("Could not write to file %1, disabling logging.").arg(m_logfile->fileName()));
-                    // Stop logging
                     enableLogging(false);
                 }
             }

src/ui/QGCMAVLinkLogPlayer.h

@@ -52,10 +52,10 @@ public slots:
     void playPause(bool play);
     /** @brief Replay the logfile */
     void play();
-    /** @brief Pause the logfile */
+    /** @brief Pause the log player. */
     void pause();
-    /** @brief Reset the logfile */
-    bool reset(int packetIndex=0);
+    /** @brief Reset the internal log player state, including the UI */
+    void reset();
     /** @brief Select logfile */
     bool selectLogFile(const QString startDirectory);
     /** @brief Select logfile */
@@ -72,21 +72,22 @@ public slots:
 signals:
     /** @brief Send ready bytes */
     void bytesReady(LinkInterface* link, const QByteArray& bytes);
+    void logFileEndReached();
 
 protected:
-    int lineCounter;
-    int totalLines;
-    quint64 startTime;
-    quint64 endTime;
-    quint64 currentStartTime;
+    quint64 playbackStartTime;     ///< The time when the logfile was first played back. This is used to pace out replaying the messages to fix long-term drift/skew. 0 indicates that the player hasn't initiated playback of this log file. In units of milliseconds since epoch UTC.
+    quint64 logCurrentTime;        ///< The timestamp of the next message in the log file. In units of microseconds since epoch UTC.
+    quint64 logStartTime;          ///< The first timestamp in the current log file. In units of microseconds since epoch UTC.
+    quint64 logEndTime;            ///< The last timestamp in the current log file. In units of microseconds since epoch UTC.
     float accelerationFactor;
     MAVLinkProtocol* mavlink;
     MAVLinkSimulationLink* logLink;
     QFile logFile;
     QTimer loopTimer;
     int loopCounter;
-    bool mavlinkLogFormat;
+    bool mavlinkLogFormat; ///< If the logfile is stored in the timestamped MAVLink log format
     int binaryBaudRate;
+    static const int defaultBinaryBaudRate = 57600;
     bool isPlaying;
     unsigned int currPacketCount;
     static const int packetLen = MAVLINK_MAX_PACKET_LEN;
@@ -100,6 +101,35 @@ protected:
 private:
     Ui::QGCMAVLinkLogPlayer *ui;
 	virtual void paintEvent(QPaintEvent *);
+
+    /** @brief Parse out a quint64 timestamp in microseconds in the proper endianness. */
+    quint64 parseTimestamp(const QByteArray &data);
+
+    /**
+     * This function parses out the next MAVLink message and its corresponding timestamp.
+     *
+     * It makes no assumptions about where in the file we currently are. It leaves the file right
+     * at the beginning of the successfully parsed message. Note that this function will not attempt to
+     * correct for any MAVLink parsing failures, so it always returns the next successfully-parsed
+     * message.
+     *
+     * @param msg[output] Where the final parsed message output will go.
+     * @return A Unix timestamp in microseconds UTC or 0 if parsing failed
+     */
+    quint64 findNextMavlinkMessage(mavlink_message_t *msg);
+
+    /**
+     * Updates the QSlider UI to be at the given percentage.
+     * @param percent A percentage value between 0.0% and 100.0%.
+     */
+    void updatePositionSliderUi(float percent);
+
+    /**
+     * Jumps to a new position in the current playback file as a percentage.
+     * @param percentage The position of the file to jump to as a percentage.
+     * @return True if the new file position was successfully jumped to, false otherwise
+     */
+    bool jumpToPlaybackLocation(float percentage);
 };
 
 #endif // QGCMAVLINKLOGPLAYER_H

src/ui/QGCMAVLinkLogPlayer.ui

@@ -29,7 +29,7 @@
    <item>
     <widget class="QLabel" name="logStatsLabel">
      <property name="text">
-      <string>No logfile selected..</string>
+      <string/>
      </property>
     </widget>
    </item>
@@ -54,6 +54,16 @@
      <property name="checkable">
       <bool>true</bool>
      </property>
+     <property name="checked">
+      <bool>false</bool>
+     </property>
+    </widget>
+   </item>
+   <item>
+    <widget class="QLabel" name="timeLabel">
+     <property name="text">
+      <string>Time</string>
+     </property>
     </widget>
    </item>
    <item>
@@ -119,7 +129,7 @@
    <item>
     <widget class="QLabel" name="logFileNameLabel">
      <property name="text">
-      <string>-</string>
+      <string>No logfile selected..</string>
      </property>
     </widget>
    </item>

src/ui/QGCStatusBar.cc

@@ -37,7 +37,7 @@ QGCStatusBar::QGCStatusBar(QWidget *parent) :
 {
     setObjectName("QGC_STATUSBAR");
 
-    toggleLoggingButton = new QPushButton("Logging", this);
+    toggleLoggingButton = new QPushButton(tr("Log to file"), this);
     toggleLoggingButton->setCheckable(true);
 
     addPermanentWidget(toggleLoggingButton);