tools: fix deprecated syntax.

This fixes a similar deprecation warning on various pieces of code:

> DeprecationWarning: Testing an element's truth value will always return True in future versions.  Use specific 'len(elem)' or 'elem is not None' test instead.
>   samples = log.find ("samples") or empty_element

tools/performance-log-coalesce.py

@@ -32,7 +32,7 @@ log = ElementTree.fromstring (sys.stdin.buffer.read ())
 
 address_map = log.find ("address-map")
 
-if address_map:
+if address_map is not None:
     addresses = []
 
     # Create base addresses dictionary

tools/performance-log-deduce.py

@@ -35,8 +35,8 @@ log = ElementTree.fromstring (sys.stdin.buffer.read ())
 # Construct state histogram
 address_states = {}
 
-for sample in (log.find ("samples") or empty_element).iterfind ("sample"):
-    threads = (sample.find ("backtrace") or empty_element).iterfind ("thread")
+for sample in (log.find ("samples") if log.find ("samples") is not None else empty_element).iterfind ("sample"):
+    threads = (sample.find ("backtrace") if sample.find ("backtrace") is not None else empty_element).iterfind ("thread")
 
     for thread in threads:
         running = int (thread.get ("running"))
@@ -73,8 +73,8 @@ for address, states in list (address_states.items ()):
         del address_states[address]
 
 # Replace thread states
-for sample in (log.find ("samples") or empty_element).iterfind ("sample"):
-    threads = (sample.find ("backtrace") or empty_element).iterfind ("thread")
+for sample in (log.find ("samples") if log.find ("samples") is not None else empty_element).iterfind ("sample"):
+    threads = (sample.find ("backtrace") if sample.find ("backtrace") is not None else empty_element).iterfind ("thread")
 
     for thread in threads:
         frame = thread.find ("frame")

tools/performance-log-expand.py

@@ -49,17 +49,19 @@ def expand_simple (element, last_values):
 last_vars      = {}
 last_backtrace = {}
 
-for sample in (log.find ("samples") or empty_element).iterfind ("sample"):
+for sample in (log.find ("samples") if log.find ("samples") is not None else empty_element).iterfind ("sample"):
     # Expand variables
-    vars = sample.find ("vars") or \
-           ElementTree.SubElement (sample, "vars")
+    vars = sample.find ("vars")
+    if vars is None:
+        vars = ElementTree.SubElement (sample, "vars")
 
     expand_simple (vars, last_vars)
 
     # Expand backtrace
     if has_backtrace:
-        backtrace = sample.find ("backtrace") or \
-                    ElementTree.SubElement (sample, "backtrace")
+        backtrace = sample.find ("backtrace")
+        if backtrace is None:
+            backtrace = ElementTree.SubElement (sample, "backtrace")
 
         for thread in backtrace:
             id     = thread.get ("id")
@@ -100,7 +102,7 @@ for sample in (log.find ("samples") or empty_element).iterfind ("sample"):
 # Expand address map
 last_address = {}
 
-for address in (log.find ("address-map") or empty_element).iterfind ("address"):
+for address in (log.find ("address-map") if log.find ("address-map") is not None else empty_element).iterfind ("address"):
     expand_simple (address, last_address)
 
 # Write performance log to STDOUT

tools/performance-log-progressive-coalesce.py

@@ -30,25 +30,27 @@ empty_element = ElementTree.Element ("")
 # Read performance log from STDIN
 log = ElementTree.fromstring (sys.stdin.buffer.read ())
 
-samples = log.find ("samples") or empty_element
+samples = log.find ("samples")
+if samples is None:
+  samples = empty_element
 
 address_map = log.find ("address-map")
 
-if not address_map:
-    address_map = ElementTree.Element ("address-map")
+if address_map is None:
+  address_map = ElementTree.Element ("address-map")
 
 # Coalesce partial address maps
 for partial_address_map in samples.iterfind ("address-map"):
-    for element in partial_address_map:
-        address_map.append (element)
+  for element in partial_address_map:
+    address_map.append (element)
 
 # Remove partial address maps
 for partial_address_map in samples.iterfind ("address-map"):
-    samples.remove (partial_address_map)
+  samples.remove (partial_address_map)
 
 # Add global address map
-if not log.find ("address-map") and len (address_map) > 0:
-    log.append (address_map)
+if log.find ("address-map") is None and len (address_map) > 0:
+  log.append (address_map)
 
 # Write performance log to STDOUT
 sys.stdout.buffer.write (ElementTree.tostring (log))

tools/performance-log-viewer.py

@@ -252,7 +252,7 @@ AddressInfo = namedtuple ("AddressInfo", ("id",
 
 address_map = {}
 
-if log.find ("address-map"):
+if log.find ("address-map") is not None:
     for address in log.find ("address-map").iterfind ("address"):
         value = int (address.get ("value"), 0)
 
@@ -308,7 +308,7 @@ for element in log.find ("samples"):
                 raw   = var.text.strip () if var.text else None
             )
 
-        if element.find ("backtrace"):
+        if element.find ("backtrace") is not None:
             for thread in element.find ("backtrace").iterfind ("thread"):
                 id      = thread.get ("id")
                 name    = thread.get ("name")
@@ -1671,12 +1671,12 @@ class InformationViewer (Gtk.ScrolledWindow):
 
         params = log.find ("params")
 
-        if params:
+        if params is not None:
             add_element (params)
 
         info = log.find ("info")
 
-        if info:
+        if info is not None:
             for element in info:
                 add_element (element)