From c8808a854b58a6370baba41a8a0de97f1d4f73fd Mon Sep 17 00:00:00 2001
From: Klaus Schmidinger <vdr@tvdr.de>
Date: Fri, 2 Mar 2012 10:43:26 +0100
Subject: [PATCH] Added a Query parameter to cDevice::GetDevice(), so that
 devices can be queried without side effects when zapping

---
 HISTORY  | 2 ++
 device.c | 8 ++++----
 device.h | 8 ++++++--
 menu.c   | 4 ++--
 4 files changed, 14 insertions(+), 8 deletions(-)

diff --git a/HISTORY b/HISTORY
index 611f0c42..fbcc0760 100644
--- a/HISTORY
+++ b/HISTORY
@@ -6944,3 +6944,5 @@ Video Disk Recorder Revision History
     attached to the device. Its boolean parameter has no meaning any more.
   + The default value for the Priority parameter of the function cDevice::ProvidesChannel()
     has been changed to IDLEPRIORITY.
+- Added a Query parameter to cDevice::GetDevice(), so that devices can be queried
+  without side effects when zapping.
diff --git a/device.c b/device.c
index 7fefbf26..9a0e4f6b 100644
--- a/device.c
+++ b/device.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: device.c 2.52 2012/03/02 10:18:44 kls Exp $
+ * $Id: device.c 2.53 2012/03/02 10:33:35 kls Exp $
  */
 
 #include "device.h"
@@ -226,7 +226,7 @@ static int GetClippedNumProvidedSystems(int AvailableBits, cDevice *Device)
   return NumProvidedSystems;
 }
 
-cDevice *cDevice::GetDevice(const cChannel *Channel, int Priority, bool LiveView)
+cDevice *cDevice::GetDevice(const cChannel *Channel, int Priority, bool LiveView, bool Query)
 {
   cDevice *AvoidDevice = avoidDevice;
   avoidDevice = NULL;
@@ -301,7 +301,7 @@ cDevice *cDevice::GetDevice(const cChannel *Channel, int Priority, bool LiveView
       if (!NumUsableSlots)
          break; // no CAM necessary, so just one loop over the devices
       }
-  if (d) {
+  if (d && !Query) {
      if (NeedsDetachReceivers)
         d->DetachAllReceivers();
      if (s) {
@@ -687,7 +687,7 @@ bool cDevice::SwitchChannel(int Direction)
      cChannel *channel;
      while ((channel = Channels.GetByNumber(n, Direction)) != NULL) {
            // try only channels which are currently available
-           if (GetDevice(channel, LIVEPRIORITY, true))
+           if (GetDevice(channel, LIVEPRIORITY, true, true))
               break;
            n = channel->Number() + Direction;
            }
diff --git a/device.h b/device.h
index e01ede3c..23aea970 100644
--- a/device.h
+++ b/device.h
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: device.h 2.35 2012/02/29 12:19:28 kls Exp $
+ * $Id: device.h 2.36 2012/03/02 10:23:13 kls Exp $
  */
 
 #ifndef __DEVICE_H
@@ -139,7 +139,7 @@ public:
          ///< Gets the device with the given Index.
          ///< \param Index must be in the range 0..numDevices-1.
          ///< \return A pointer to the device, or NULL if the Index was invalid.
-  static cDevice *GetDevice(const cChannel *Channel, int Priority, bool LiveView);
+  static cDevice *GetDevice(const cChannel *Channel, int Priority, bool LiveView, bool Query = false);
          ///< Returns a device that is able to receive the given Channel at the
          ///< given Priority, with the least impact on active recordings and
          ///< live viewing. The LiveView parameter tells whether the device will
@@ -153,6 +153,10 @@ public:
          ///< after detaching any receivers because the channel can't be decrypted,
          ///< this device/CAM combination will be skipped in the next call to
          ///< GetDevice().
+         ///< If Query is true, no actual CAM assignments or receiver detachments will
+         ///< be done, so that this function can be called without any side effects
+         ///< in order to just determine whether a device is available for the given
+         ///< Channel.
          ///< See also ProvidesChannel().
   static void SetAvoidDevice(cDevice *Device) { avoidDevice = Device; }
          ///< Sets the given Device to be temporarily avoided in the next call to
diff --git a/menu.c b/menu.c
index 053e4e74..7866bc3d 100644
--- a/menu.c
+++ b/menu.c
@@ -4,7 +4,7 @@
  * See the main source file 'vdr.c' for copyright information and
  * how to reach the author.
  *
- * $Id: menu.c 2.38 2012/02/25 13:50:49 kls Exp $
+ * $Id: menu.c 2.39 2012/03/02 10:33:17 kls Exp $
  */
 
 #include "menu.h"
@@ -3653,7 +3653,7 @@ cChannel *cDisplayChannel::NextAvailableChannel(cChannel *Channel, int Direction
            Channel = Direction > 0 ? Channels.Next(Channel) : Channels.Prev(Channel);
            if (!Channel && Setup.ChannelsWrap)
               Channel = Direction > 0 ? Channels.First() : Channels.Last();
-           if (Channel && !Channel->GroupSep() && cDevice::GetDevice(Channel, LIVEPRIORITY, true))
+           if (Channel && !Channel->GroupSep() && cDevice::GetDevice(Channel, LIVEPRIORITY, true, true))
               return Channel;
            }
      }