New test infrastructure for producing verbose logs in failing tests.

chrome/test/base/log_file_reader_win.h

+// Copyright (c) 2012 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.
+
+// A log file reader can read log files produced by Event Tracing for Windows
+// (by way of the FileLogger class) that contain events generated from a select
+// few supported providers; see file_logger_win.h for the list.
+
+#ifndef CHROME_TEST_BASE_LOG_FILE_READER_WIN_H_
+#define CHROME_TEST_BASE_LOG_FILE_READER_WIN_H_
+#pragma once
+
+#include <stddef.h>
+#include <windows.h>
+#include <wmistr.h>
+#include <evntrace.h>
+
+#include "base/logging.h"
+#include "base/string_piece.h"
+
+class FilePath;
+
+namespace logging_win {
+
+// An interface to classes interested in taking action based on events parsed
+// out of a log file created by the FileLogger.
+class LogFileDelegate {
+ public:
+  virtual ~LogFileDelegate();
+
+  // Invoked for event types not currently handled by the parser.
+  virtual void OnUnknownEvent(const EVENT_TRACE* event) = 0;
+
+  // Invoked for events of known types that cannot be parsed due to unexpected
+  // data.
+  virtual void OnUnparsableEvent(const EVENT_TRACE* event) = 0;
+
+  // Invoked for the header at the front of all log files.
+  virtual void OnFileHeader(const EVENT_TRACE* event,
+                            const TRACE_LOGFILE_HEADER* header) = 0;
+
+  // Invoked for simple log messages produced by LogEventProvider.
+  virtual void OnLogMessage(const EVENT_TRACE* event,
+                            logging::LogSeverity severity,
+                            const base::StringPiece& message) = 0;
+
+  // Invoked for full log messages produced by LogEventProvider.
+  virtual void OnLogMessageFull(const EVENT_TRACE* event,
+                                logging::LogSeverity severity,
+                                DWORD stack_depth,
+                                const intptr_t* backtrace,
+                                int line,
+                                const base::StringPiece& file,
+                                const base::StringPiece& message) = 0;
+
+  // Invoked for trace events produced by TraceEventETWProvider.
+  virtual void OnTraceEvent(const EVENT_TRACE* event,
+                            const base::StringPiece& name,
+                            char type,
+                            intptr_t id,

[robertshield, 2012/03/09 16:58:04]

intptr_t seems like an odd type for an ID.

[grt (UTC plus 2), 2012/03/09 17:55:25]

Indeed.  a void* is used in the creation of a trace event.  Reading this value
as a pointer sometime later doesn't make sense to me, whereas treating it as a
pointer-sized int does.  WDYT?

+                            const base::StringPiece& extra,
+                            DWORD stack_depth,
+                            const intptr_t* backtrace) = 0;
+
+ protected:
+  LogFileDelegate();
+};
+
+// Reads |log_file|, invoking appropriate methods on |delegate| as events are
+// parsed.  Although it is safe to call this from multiple threads, only one
+// file may be read at a time; other threads trying to read other log files will
+// be blocked waiting.
+void ReadLogFile(const FilePath& log_file, LogFileDelegate* delegate);
+
+}  // namespace logging_win
+
+#endif  // CHROME_TEST_BASE_LOG_FILE_READER_WIN_H_