Add coverage

tools/telemetry/third_party/coverage/coverage/plugin_support.py

Index: tools/telemetry/third_party/coverage/coverage/plugin_support.py
diff --git a/tools/telemetry/third_party/coverage/coverage/plugin_support.py b/tools/telemetry/third_party/coverage/coverage/plugin_support.py
new file mode 100644
index 0000000000000000000000000000000000000000..f88342e9918cac8dbea5af65103890e07d41d5ec
--- /dev/null
+++ b/tools/telemetry/third_party/coverage/coverage/plugin_support.py
@@ -0,0 +1,244 @@
+# Licensed under the Apache License: http://www.apache.org/licenses/LICENSE-2.0
+# For details: https://bitbucket.org/ned/coveragepy/src/default/NOTICE.txt
+
+"""Support for plugins."""
+
+import os.path
+import sys
+
+from coverage.misc import CoverageException
+from coverage.plugin import CoveragePlugin, FileTracer, FileReporter
+
+
+class Plugins(object):
+    """The currently loaded collection of coverage.py plugins."""
+
+    def __init__(self):
+        self.order = []
+        self.names = {}
+        self.file_tracers = []
+
+        self.current_module = None
+        self.debug = None
+
+    @classmethod
+    def load_plugins(cls, modules, config, debug=None):
+        """Load plugins from `modules`.
+
+        Returns a list of loaded and configured plugins.
+
+        """
+        plugins = cls()
+        plugins.debug = debug
+
+        for module in modules:
+            plugins.current_module = module
+            __import__(module)
+            mod = sys.modules[module]
+
+            coverage_init = getattr(mod, "coverage_init", None)
+            if not coverage_init:
+                raise CoverageException(
+                    "Plugin module %r didn't define a coverage_init function" % module
+                )
+
+            options = config.get_plugin_options(module)
+            coverage_init(plugins, options)
+
+        plugins.current_module = None
+        return plugins
+
+    def add_file_tracer(self, plugin):
+        """Add a file tracer plugin.
+
+        `plugin` is an instance of a third-party plugin class.  It must
+        implement the :meth:`CoveragePlugin.file_tracer` method.
+
+        """
+        self._add_plugin(plugin, self.file_tracers)
+
+    def add_noop(self, plugin):
+        """Add a plugin that does nothing.
+
+        This is only useful for testing the plugin support.
+
+        """
+        self._add_plugin(plugin, None)
+
+    def _add_plugin(self, plugin, specialized):
+        """Add a plugin object.
+
+        `plugin` is a :class:`CoveragePlugin` instance to add.  `specialized`
+        is a list to append the plugin to.
+
+        """
+        plugin_name = "%s.%s" % (self.current_module, plugin.__class__.__name__)
+        if self.debug and self.debug.should('plugin'):
+            self.debug.write("Loaded plugin %r: %r" % (self.current_module, plugin))
+            labelled = LabelledDebug("plugin %r" % (self.current_module,), self.debug)
+            plugin = DebugPluginWrapper(plugin, labelled)
+
+        # pylint: disable=attribute-defined-outside-init
+        plugin._coverage_plugin_name = plugin_name
+        plugin._coverage_enabled = True
+        self.order.append(plugin)
+        self.names[plugin_name] = plugin
+        if specialized is not None:
+            specialized.append(plugin)
+
+    def __nonzero__(self):
+        return bool(self.order)
+
+    __bool__ = __nonzero__
+
+    def __iter__(self):
+        return iter(self.order)
+
+    def get(self, plugin_name):
+        """Return a plugin by name."""
+        return self.names[plugin_name]
+
+
+class LabelledDebug(object):
+    """A Debug writer, but with labels for prepending to the messages."""
+
+    def __init__(self, label, debug, prev_labels=()):
+        self.labels = list(prev_labels) + [label]
+        self.debug = debug
+
+    def add_label(self, label):
+        """Add a label to the writer, and return a new `LabelledDebug`."""
+        return LabelledDebug(label, self.debug, self.labels)
+
+    def message_prefix(self):
+        """The prefix to use on messages, combining the labels."""
+        prefixes = self.labels + ['']
+        return ":\n".join("  "*i+label for i, label in enumerate(prefixes))
+
+    def write(self, message):
+        """Write `message`, but with the labels prepended."""
+        self.debug.write("%s%s" % (self.message_prefix(), message))
+
+
+class DebugPluginWrapper(CoveragePlugin):
+    """Wrap a plugin, and use debug to report on what it's doing."""
+
+    def __init__(self, plugin, debug):
+        super(DebugPluginWrapper, self).__init__()
+        self.plugin = plugin
+        self.debug = debug
+
+    def file_tracer(self, filename):
+        tracer = self.plugin.file_tracer(filename)
+        self.debug.write("file_tracer(%r) --> %r" % (filename, tracer))
+        if tracer:
+            debug = self.debug.add_label("file %r" % (filename,))
+            tracer = DebugFileTracerWrapper(tracer, debug)
+        return tracer
+
+    def file_reporter(self, filename):
+        reporter = self.plugin.file_reporter(filename)
+        self.debug.write("file_reporter(%r) --> %r" % (filename, reporter))
+        if reporter:
+            debug = self.debug.add_label("file %r" % (filename,))
+            reporter = DebugFileReporterWrapper(filename, reporter, debug)
+        return reporter
+
+    def sys_info(self):
+        return self.plugin.sys_info()
+
+
+class DebugFileTracerWrapper(FileTracer):
+    """A debugging `FileTracer`."""
+
+    def __init__(self, tracer, debug):
+        self.tracer = tracer
+        self.debug = debug
+
+    def _show_frame(self, frame):
+        """A short string identifying a frame, for debug messages."""
+        return "%s@%d" % (
+            os.path.basename(frame.f_code.co_filename),
+            frame.f_lineno,
+        )
+
+    def source_filename(self):
+        sfilename = self.tracer.source_filename()
+        self.debug.write("source_filename() --> %r" % (sfilename,))
+        return sfilename
+
+    def has_dynamic_source_filename(self):
+        has = self.tracer.has_dynamic_source_filename()
+        self.debug.write("has_dynamic_source_filename() --> %r" % (has,))
+        return has
+
+    def dynamic_source_filename(self, filename, frame):
+        dyn = self.tracer.dynamic_source_filename(filename, frame)
+        self.debug.write("dynamic_source_filename(%r, %s) --> %r" % (
+            filename, self._show_frame(frame), dyn,
+        ))
+        return dyn
+
+    def line_number_range(self, frame):
+        pair = self.tracer.line_number_range(frame)
+        self.debug.write("line_number_range(%s) --> %r" % (self._show_frame(frame), pair))
+        return pair
+
+
+class DebugFileReporterWrapper(FileReporter):
+    """A debugging `FileReporter`."""
+
+    def __init__(self, filename, reporter, debug):
+        super(DebugFileReporterWrapper, self).__init__(filename)
+        self.reporter = reporter
+        self.debug = debug
+
+    def relative_filename(self):
+        ret = self.reporter.relative_filename()
+        self.debug.write("relative_filename() --> %r" % (ret,))
+        return ret
+
+    def lines(self):
+        ret = self.reporter.lines()
+        self.debug.write("lines() --> %r" % (ret,))
+        return ret
+
+    def excluded_lines(self):
+        ret = self.reporter.excluded_lines()
+        self.debug.write("excluded_lines() --> %r" % (ret,))
+        return ret
+
+    def translate_lines(self, lines):
+        ret = self.reporter.translate_lines(lines)
+        self.debug.write("translate_lines(%r) --> %r" % (lines, ret))
+        return ret
+
+    def translate_arcs(self, arcs):
+        ret = self.reporter.translate_arcs(arcs)
+        self.debug.write("translate_arcs(%r) --> %r" % (arcs, ret))
+        return ret
+
+    def no_branch_lines(self):
+        ret = self.reporter.no_branch_lines()
+        self.debug.write("no_branch_lines() --> %r" % (ret,))
+        return ret
+
+    def exit_counts(self):
+        ret = self.reporter.exit_counts()
+        self.debug.write("exit_counts() --> %r" % (ret,))
+        return ret
+
+    def arcs(self):
+        ret = self.reporter.arcs()
+        self.debug.write("arcs() --> %r" % (ret,))
+        return ret
+
+    def source(self):
+        ret = self.reporter.source()
+        self.debug.write("source() --> %d chars" % (len(ret),))
+        return ret
+
+    def source_token_lines(self):
+        ret = list(self.reporter.source_token_lines())
+        self.debug.write("source_token_lines() --> %d tokens" % (len(ret),))
+        return ret