Updated stats-viewer.py to work with chromium.

tools/stats-viewer.py

+#!/usr/bin/env python
+#
 # Copyright 2008 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 31 matching lines @@
 
 
 # The interval, in milliseconds, between ui updates
 UPDATE_INTERVAL_MS = 100
 
 
 # Mapping from counter prefix to the formatting to be used for the counter
 COUNTER_LABELS = {"t": "%i ms.", "c": "%i"}
 
 
-# The magic number used to check if a file is not a counters file
+# The magic numbers used to check if a file is not a counters file
 COUNTERS_FILE_MAGIC_NUMBER = 0xDEADFACE
+CHROME_COUNTERS_FILE_MAGIC_NUMBER = 0x13131313
 
 
 class StatsViewer(object):
   """The main class that keeps the data used by the stats viewer."""
 
   def __init__(self, data_name):
     """Creates a new instance.
 
     Args:
       data_name: the name of the file containing the counters.
@@ skipping 28 matching lines @@
     something goes wrong print an informative message and exit the
     program."""
     if not os.path.exists(self.data_name):
       print "File %s doesn't exist." % self.data_name
       sys.exit(1)
     data_file = open(self.data_name, "r")
     size = os.fstat(data_file.fileno()).st_size
     fileno = data_file.fileno()
     self.shared_mmap = mmap.mmap(fileno, size, access=mmap.ACCESS_READ)
     data_access = SharedDataAccess(self.shared_mmap)
-    if data_access.IntAt(0) != COUNTERS_FILE_MAGIC_NUMBER:
-      print "File %s is not stats data." % self.data_name
-      sys.exit(1)
-    return CounterCollection(data_access)
+    if data_access.IntAt(0) == COUNTERS_FILE_MAGIC_NUMBER:
+      return CounterCollection(data_access)
+    elif data_access.IntAt(0) == CHROME_COUNTERS_FILE_MAGIC_NUMBER:
+      return ChromeCounterCollection(data_access)
+    print "File %s is not stats data." % self.data_name
+    sys.exit(1)
 
   def CleanUp(self):
     """Cleans up the memory mapped file if necessary."""
     if self.shared_mmap:
       self.shared_mmap.close()
 
   def UpdateCounters(self):
     """Read the contents of the memory-mapped file and update the ui if
     necessary.  If the same counters are present in the file as before
     we just update the existing labels.  If any counters have been added
@@ skipping 233 matching lines @@
 
   def Counter(self, index):
     """Return the index'th counter."""
     return Counter(self.data, 16 + index * self.CounterSize())
 
   def CounterSize(self):
     """Return the size of a single counter."""
     return 4 + self.max_name_size
 
 
+class ChromeCounter(object):
+  """A pointer to a single counter withing a binary counters file."""
+
+  def __init__(self, data, name_offset, value_offset):
+    """Create a new instance.
+
+    Args:
+      data: the shared data access object containing the counter
+      name_offset: the byte offset of the start of this counter's name
+      value_offset: the byte offset of the start of this counter's value
+    """
+    self.data = data
+    self.name_offset = name_offset
+    self.value_offset = value_offset
+
+  def Value(self):
+    """Return the integer value of this counter."""
+    return self.data.IntAt(self.value_offset)
+
+  def Name(self):
+    """Return the ascii name of this counter."""
+    result = ""
+    index = self.name_offset
+    current = self.data.ByteAt(index)
+    while current:
+      result += chr(current)
+      index += 1
+      current = self.data.ByteAt(index)
+    return result
+
+
+class ChromeCounterCollection(object):
+  """An overlay over a counters file that provides access to the
+  individual counters contained in the file."""
+
+  _HEADER_SIZE = 4 * 4
+  _NAME_SIZE = 32
+
+  def __init__(self, data):
+    """Create a new instance.
+
+    Args:
+      data: the shared data access object
+    """
+    self.data = data
+    self.max_counters = data.IntAt(8)
+    self.max_threads = data.IntAt(12)
+    self.counter_names_offset = \
+        self._HEADER_SIZE + self.max_threads * (self._NAME_SIZE + 2 * 4)
+    self.counter_values_offset = \
+        self.counter_names_offset + self.max_counters * self._NAME_SIZE
+
+  def CountersInUse(self):
+    """Return the number of counters in active use."""
+    for i in xrange(self.max_counters):
+      if self.data.ByteAt(self.counter_names_offset + i * self._NAME_SIZE) == 0:
+        return i
+    return self.max_counters
+
+  def Counter(self, i):
+    """Return the i'th counter."""
+    return ChromeCounter(self.data,
+                         self.counter_names_offset + i * self._NAME_SIZE,
+                         self.counter_values_offset + i * self.max_threads * 4)
+
+
 def Main(data_file):
   """Run the stats counter.
 
   Args:
     data_file: The counters file to monitor.
   """
   StatsViewer(data_file).Run()
 
 
 if __name__ == "__main__":
   if len(sys.argv) != 2:
     print "Usage: stats-viewer.py <stats data>"
     sys.exit(1)
   Main(sys.argv[1])