From 19344e8d8c77a6f5429e4fd496ddb109a8983e0b Mon Sep 17 00:00:00 2001
From: Nodir Temirkhodjaev <nodir.temir@gmail.com>
Date: Fri, 23 Feb 2018 15:33:28 +0500
Subject: [PATCH] UI: LogManager: Fix buffers handling.

---
 src/ui/driver/driverworker.cpp |  7 ++++++-
 src/ui/driver/driverworker.h   |  2 +-
 src/ui/log/logmanager.cpp      | 14 +++++++++-----
 src/ui/log/logmanager.h        |  2 +-
 4 files changed, 17 insertions(+), 8 deletions(-)

diff --git a/src/ui/driver/driverworker.cpp b/src/ui/driver/driverworker.cpp
index a8c71123..5e3bcc66 100644
--- a/src/ui/driver/driverworker.cpp
+++ b/src/ui/driver/driverworker.cpp
@@ -22,15 +22,20 @@ void DriverWorker::run()
     } while (!m_aborted);
 }
 
-void DriverWorker::readLogAsync(LogBuffer *logBuffer)
+bool DriverWorker::readLogAsync(LogBuffer *logBuffer)
 {
     QMutexLocker locker(&m_mutex);
 
+    if (m_logBuffer)
+        return false;
+
     m_cancelled = false;
 
     m_logBuffer = logBuffer;
 
     m_waitCondition.wakeOne();
+
+    return true;
 }
 
 void DriverWorker::cancelAsyncIo()
diff --git a/src/ui/driver/driverworker.h b/src/ui/driver/driverworker.h
index 47fd559b..75728ac3 100644
--- a/src/ui/driver/driverworker.h
+++ b/src/ui/driver/driverworker.h
@@ -23,7 +23,7 @@ signals:
                        const QString &errorMessage);
 
 public slots:
-    void readLogAsync(LogBuffer *logBuffer);
+    bool readLogAsync(LogBuffer *logBuffer);
     void cancelAsyncIo();
     void abort();
 
diff --git a/src/ui/log/logmanager.cpp b/src/ui/log/logmanager.cpp
index 003ef33a..46f10327 100644
--- a/src/ui/log/logmanager.cpp
+++ b/src/ui/log/logmanager.cpp
@@ -27,10 +27,9 @@ void LogManager::setActive(bool active)
         m_active = active;
 
         if (m_active) {
-            readLogAsync(getFreeBuffer());
+            readLogAsync();
         } else {
             cancelAsyncIo();
-            readLogAsync(nullptr);
         }
 
         emit activeChanged();
@@ -56,9 +55,13 @@ void LogManager::setupDriverWorker()
             this, &LogManager::processLogBuffer, Qt::QueuedConnection);
 }
 
-void LogManager::readLogAsync(LogBuffer *logBuffer)
+void LogManager::readLogAsync()
 {
-    m_driverWorker->readLogAsync(logBuffer);
+    LogBuffer *logBuffer = getFreeBuffer();
+
+    if (!m_driverWorker->readLogAsync(logBuffer)) {
+        addFreeBuffer(logBuffer);
+    }
 }
 
 void LogManager::cancelAsyncIo()
@@ -84,7 +87,7 @@ void LogManager::processLogBuffer(LogBuffer *logBuffer, bool success,
                                   const QString &errorMessage)
 {
     if (m_active) {
-        readLogAsync(getFreeBuffer());
+        readLogAsync();
     }
 
     if (success) {
@@ -124,6 +127,7 @@ void LogManager::readLogEntries(LogBuffer *logBuffer)
             break;
         }
         default:
+            Q_ASSERT(logBuffer->offset() != 0);
             return;
         }
     }
diff --git a/src/ui/log/logmanager.h b/src/ui/log/logmanager.h
index 18d65f49..d0125742 100644
--- a/src/ui/log/logmanager.h
+++ b/src/ui/log/logmanager.h
@@ -46,7 +46,7 @@ private:
 
     void setupDriverWorker();
 
-    void readLogAsync(LogBuffer *logBuffer);
+    void readLogAsync();
     void cancelAsyncIo();
 
     LogBuffer *getFreeBuffer();