refactor sources to be more flexible

owrx/source/direct.py

@@ -0,0 +1,53 @@
+from abc import ABCMeta
+from . import SdrSource
+
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class DirectSource(SdrSource, metaclass=ABCMeta):
+    def onPropertyChange(self, name, value):
+        logger.debug("restarting sdr source due to property change: {0} changed to {1}".format(name, value))
+        self.stop()
+        self.sleepOnRestart()
+        self.start()
+
+    def getEventNames(self):
+        return super().getEventNames() + [
+            "nmux_memory",
+        ]
+
+    def getNmuxCommand(self):
+        props = self.rtlProps
+
+        nmux_bufcnt = nmux_bufsize = 0
+        while nmux_bufsize < props["samp_rate"] / 4:
+            nmux_bufsize += 4096
+        while nmux_bufsize * nmux_bufcnt < props["nmux_memory"] * 1e6:
+            nmux_bufcnt += 1
+        if nmux_bufcnt == 0 or nmux_bufsize == 0:
+            raise ValueError(
+                "Error: nmux_bufsize or nmux_bufcnt is zero. "
+                "These depend on nmux_memory and samp_rate options in config_webrx.py"
+            )
+
+        return "nmux --bufsize %d --bufcnt %d --port %d --address 127.0.0.1" % (
+            nmux_bufsize,
+            nmux_bufcnt,
+            self.port,
+        )
+
+    def getCommand(self):
+        return super().getCommand() + [
+            self.getFormatConversion(),
+            self.getNmuxCommand(),
+        ]
+
+    # override this in subclasses, if necessary
+    def getFormatConversion(self):
+        return None
+
+    # override this in subclasses, if necessary
+    def sleepOnRestart(self):
+        pass