From: whitequark <whitequark@whitequark.org>
Date: Wed, 12 Feb 2020 14:42:06 +0000 (+0000)
Subject: back.pysim: accept write_vcd(vcd_file=None).
X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=2860f3accb712a5d01d0a91a868d95b1fb89ae36;p=nmigen.git

back.pysim: accept write_vcd(vcd_file=None).

Because write_vcd() is a context manager, this is useful if the VCD
file should be sometimes not written, since it avoids awkward
conditionals with duplicated code. It's not very elegant though.

Fixes #319.
---

diff --git a/nmigen/back/pysim.py b/nmigen/back/pysim.py
index 9ae476f..6fe3d9e 100644
--- a/nmigen/back/pysim.py
+++ b/nmigen/back/pysim.py
@@ -94,6 +94,9 @@ class _VCDWaveformWriter(_WaveformWriter):
                 trace_names[trace] = trace.name
             self.traces.append(trace)
 
+        if self.vcd_writer is None:
+            return
+
         for signal, names in itertools.chain(signal_names.items(), trace_names.items()):
             if signal.decoder:
                 var_type = "string"
@@ -139,7 +142,8 @@ class _VCDWaveformWriter(_WaveformWriter):
             self.vcd_writer.change(vcd_var, vcd_timestamp, var_value)
 
     def close(self, timestamp):
-        self.vcd_writer.close(self.timestamp_to_vcd(timestamp))
+        if self.vcd_writer is not None:
+            self.vcd_writer.close(self.timestamp_to_vcd(timestamp))
 
         if self.gtkw_save is not None:
             self.gtkw_save.dumpfile(self.vcd_file.name)
@@ -153,7 +157,8 @@ class _VCDWaveformWriter(_WaveformWriter):
                     suffix = ""
                 self.gtkw_save.trace(".".join(self.gtkw_names[signal]) + suffix)
 
-        self.vcd_file.close()
+        if self.vcd_file is not None:
+            self.vcd_file.close()
         if self.gtkw_file is not None:
             self.gtkw_file.close()