[DO NOT COMMIT] Refactor systrace to support new clock sync design

systrace/systrace/systrace_tracing_controller.py

Index: systrace/systrace/systrace_tracing_controller.py
diff --git a/systrace/systrace/systrace_tracing_controller.py b/systrace/systrace/systrace_tracing_controller.py
new file mode 100644
index 0000000000000000000000000000000000000000..bf37f676379a693ef601377855db91a11477a11f
--- /dev/null
+++ b/systrace/systrace/systrace_tracing_controller.py
@@ -0,0 +1,148 @@
+#!/usr/bin/env python
+
+# Copyright (c) 2016 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+'''Implementation of tracing controller for systrace. This class creates the
+necessary tracing agents for systrace, runs them, and outputs the results
+as an HTML file.'''
+
+import imp
+import os
+from systrace import tracing_controller
+
+# The default agent directory.
+DEFAULT_AGENT_DIR = 'agents'
+
+
+class SystraceTracingController(tracing_controller.TracingController):
+  def __init__(self, script_dir, options, categories):
+    """Set up the SystraceTracingController.
+
+    Args:
+        script_dir: Directory containing the trace viewer script
+                    (systrace_trace_viewer.html)
+        options: List of command line options.
+        categories: List of trace categories to capture.
+    """
+    # Parse command line arguments and create agents
+    self._script_dir = script_dir
+    self._html_filename = options.output_file
+    self._all_results = None

[Zhen Wang, 2016/03/14 17:11:27]

I think you don't want to override self._all_results in parent class
(tracing_controller.TracingController)?

[alexandermont, 2016/03/14 22:19:28]

Fixed

+    agents = CreateAgents(options, categories)
+
+    # Error if no agents are available
+    if not agents:
+      dirs = DEFAULT_AGENT_DIR
+      if options.agent_dirs:
+        dirs += ',' + options.agent_dirs
+      raise RuntimeError('No systrace agent is available'
+                         'in directories |%s|.\n' % dirs)
+
+    # Update trace viewer if necessary
+    try:
+      update_systrace_trace_viewer = __import__('update_systrace_trace_viewer')
+    except ImportError:
+      pass
+    else:
+      update_systrace_trace_viewer.update()
+
+    super(SystraceTracingController, self).__init__(agents)
+
+  #override
+  def SupportsExplicitClockSync(self):
+    return False
+
+  #override
+  def RecordClockSyncMarker(self, sync_id, callback):
+    raise NotImplementedError
+
+  def OutputSystraceResults(self, json=False):
+    """Output the results of systrace to a file if
+    output is necessary.
+
+    Args:
+       json: Whether to output to a json file (if false, use HTML file)
+    """
+    if all([x.should_output_trace for x in self._all_results]):
+      print 'Tracing complete, writing results'
+      if json:
+        self._WriteTraceJSON(self._all_results)
+      else:
+        self._WriteTraceHTML(self._all_results)
+    else:
+      print 'Tracing complete, results not required'
+
+  def _WriteTraceJSON(self, results):
+    raise NotImplementedError # TODO: write this function
+
+  def _WriteTraceHTML(self, results):
+    """Write the results of systrace to an HTML file."""
+    def _read_asset(src_dir, filename):
+      return open(os.path.join(src_dir, filename)).read()
+
+    print 'Writing trace HTML'
+    systrace_dir = os.path.abspath(os.path.dirname(__file__))
+    html_prefix = _read_asset(systrace_dir, 'prefix.html')
+    html_suffix = _read_asset(systrace_dir, 'suffix.html')
+    trace_viewer_html = _read_asset(self._script_dir,
+                                    'systrace_trace_viewer.html')
+
+    # Open the file in binary mode to prevent python from changing the
+    # line endings.
+    html_file = open(self._html_filename, 'wb')
+    html_file.write(html_prefix.replace('{{SYSTRACE_TRACE_VIEWER_HTML}}',
+                                        trace_viewer_html))
+
+    html_file.write('<!-- BEGIN TRACE -->\n')
+    for a in results:
+      if a.trace_data:
+        html_file.write('  <script class="')
+        html_file.write('trace-data')
+        html_file.write('" type="application/text">\n')
+        html_file.write(a.trace_data)
+        html_file.write('  </script>\n')
+    html_file.write('<!-- END TRACE -->\n')
+
+    html_file.write(html_suffix)
+    html_file.close()
+    print '\n    wrote file://%s\n' % os.path.abspath(self._html_filename)
+
+def CreateAgents(options, categories):
+  """Create systrace agents.
+
+  This function will search systrace agent modules in agent directories and
+  create the corresponding systrace agents.
+  Args:
+    options: The command-line options.
+    categories: The trace categories to capture.
+  Returns:
+    The list of systrace agents.
+  """
+  agent_dirs = [os.path.join(os.path.dirname(__file__),
+                             DEFAULT_AGENT_DIR)]
+  if options.agent_dirs:
+    agent_dirs.extend(options.agent_dirs.split(','))
+
+  agents = []
+  for agent_dir in agent_dirs:
+    if not agent_dir:
+      continue
+    for filename in os.listdir(agent_dir):
+      (module_name, ext) = os.path.splitext(filename)
+      if (ext != '.py' or module_name == '__init__'
+          or module_name.endswith('_unittest')):
+        continue
+      (f, pathname, data) = imp.find_module(module_name, [agent_dir])
+      try:
+        module = imp.load_module(module_name, f, pathname, data)
+      finally:
+        if f:
+          f.close()
+      if module:
+        agent = module.try_create_agent(options, categories)
+        if not agent:
+          continue
+        agents.append(agent)
+  return agents