Fixes #9927. Make sure we always join the pthread in the DeviceReadBu…

…ffer. We didn't do this when the DRB exited on an error.
MythTV · Jul 26, 2011 · 760c8db · 760c8db
1 parent 23305b9
commit 760c8db
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Showing 2 changed files with 24 additions and 6 deletions.
diff --git a/mythtv/libs/libmythtv/DeviceReadBuffer.cpp b/mythtv/libs/libmythtv/DeviceReadBuffer.cpp
@@ -19,7 +19,7 @@ using namespace std;
 
 DeviceReadBuffer::DeviceReadBuffer(ReaderPausedCB *cb, bool use_poll)
     : videodevice(""),              _stream_fd(-1),
-      readerPausedCB(cb),
+      readerPausedCB(cb),           thread_exists(false),
 
       // Data for managing the device ringbuffer
       run(false),                   running(false),
@@ -41,6 +41,8 @@ DeviceReadBuffer::DeviceReadBuffer(ReaderPausedCB *cb, bool use_poll)
 
 DeviceReadBuffer::~DeviceReadBuffer()
 {
+    if (thread_exists)
+        Stop();
     if (buffer)
         delete[] buffer;
 }
@@ -95,15 +97,14 @@ bool DeviceReadBuffer::Setup(const QString &streamName, int streamfd)
 
 void DeviceReadBuffer::Start(void)
 {
-    bool was_running;
+    QMutexLocker locker(&thread_lock);
 
     {
         QMutexLocker locker(&lock);
-        was_running = running;
         error = false;
     }
 
-    if (was_running)
+    if (thread_exists)
     {
         VERBOSE(VB_IMPORTANT, LOC_ERR + "Start(): Already running.");
         SetRequestPause(false);
@@ -117,7 +118,10 @@ void DeviceReadBuffer::Start(void)
 
         QMutexLocker locker(&lock);
         error = true;
+        return;
     }
+
+    thread_exists = true;
 }
 
 void DeviceReadBuffer::Reset(const QString &streamName, int streamfd)
@@ -137,9 +141,9 @@ void DeviceReadBuffer::Reset(const QString &streamName, int streamfd)
 
 void DeviceReadBuffer::Stop(void)
 {
-    bool was_running = IsRunning();
+    QMutexLocker locker(&thread_lock);
 
-    if (!was_running)
+    if (!thread_exists)
     {
         VERBOSE(VB_IMPORTANT, LOC + "Stop(): Not running.");
         return;
@@ -151,6 +155,7 @@ void DeviceReadBuffer::Stop(void)
     }
 
     pthread_join(thread, NULL);
+    thread_exists = false;
 }
 
 void DeviceReadBuffer::SetRequestPause(bool req)

diff --git a/mythtv/libs/libmythtv/DeviceReadBuffer.h b/mythtv/libs/libmythtv/DeviceReadBuffer.h
@@ -13,6 +13,12 @@
 
 #include "util.h"
 
+// Locking order
+//
+// thread_lock -> lock
+//
+// See tv_play.h for an explanation of locking order.
+
 class ReaderPausedCB
 {
   protected:
@@ -77,11 +83,18 @@ class DeviceReadBuffer
     int              _stream_fd;
 
     ReaderPausedCB  *readerPausedCB;
+
+    // Manage access to thread variable
+    mutable QMutex   thread_lock;
+    /// True if a thread has been created and needs reaping
+    bool             thread_exists;
     pthread_t        thread;
 
     // Data for managing the device ringbuffer
     mutable QMutex   lock;
+    /// true when we want the thread to be running
     bool             run;
+    /// true if the read thread is doing work
     bool             running;
     bool             eof;
     mutable bool     error;