Add mutex to Audio_File objects to prevent read_source_peaks() and IO thread from conflicting.

Timeline/Audio_File.H

@@ -29,9 +29,11 @@
 #include <map>
 #include <list>
 
+#include "Mutex.H"
+
 class Peak_Writer;
 
-class Audio_File
+class Audio_File : protected Mutex
 {
     static std::map <std::string, Audio_File*> _open_files;
 

Timeline/Audio_File_SF.C

@@ -163,10 +163,12 @@ Audio_File_SF::close ( void )
 void
 Audio_File_SF::seek ( nframes_t offset )
 {
+    lock();
+
     if ( offset != _current_read )
-    {
         sf_seek( _in, _current_read = offset, SEEK_SET | SFM_READ );
-    }
+
+    unlock();
 }
 
 /* if channels is -1, then all channels are read into buffer
@@ -179,6 +181,8 @@ Audio_File_SF::read ( sample_t *buf, int channel, nframes_t len )
 
 //    printf( "len = %lu, channels = %d\n", len, _channels );
 
+    lock();
+
     nframes_t rlen;
 
     if ( _channels == 1 || channel == -1 )
@@ -198,6 +202,8 @@ Audio_File_SF::read ( sample_t *buf, int channel, nframes_t len )
 
     _current_read += rlen;
 
+    unlock();
+
     return rlen;
 }
 
@@ -207,12 +213,15 @@ Audio_File_SF::read ( sample_t *buf, int channel, nframes_t start, nframes_t end
 {
     assert( end > start );
 
+    lock();
 //    open();
 
     seek( start );
 
     nframes_t len = read( buf, channel, end - start );
 
+    unlock();
+
 //    close();
 
     return len;
@@ -225,9 +234,13 @@ Audio_File_SF::write ( sample_t *buf, nframes_t nframes )
 {
     _peaks.write( buf, nframes );
 
+//    lock();
+
     nframes_t l = sf_writef_float( _in, buf, nframes );
 
     _length += l;
 
+//    unlock();
+
     return l;
 }

Timeline/Audio_File_SF.H

@@ -29,7 +29,7 @@ class Audio_File_SF : public Audio_File
 
     /* used to avoid unnecessary seeking--libsndfile isn't smart
      * enough to do this for us */
-    nframes_t _current_read;
+    volatile nframes_t _current_read;
 
     Audio_File_SF ( )
         {