Implemented VLOG() et al.

Implemented VLOG(), VLOG_IF(), VLOG_IS_ON().  Added --v and --vmodule
switches.

Changed some spammy sync-related logs to use VLOG.

BUG=56965
TEST=New unittests

Review URL: http://codereview.chromium.org/3448028

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@60976 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 51 insertions, 0 deletions

diff --git a/base/vlog.h b/base/vlog.h
new file mode 100644
index 0000000..faa62ec
--- /dev/null
+++ b/base/vlog.h
@@ -0,0 +1,51 @@
+// Copyright (c) 2010 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.
+
+#ifndef BASE_VLOG_H_
+#define BASE_VLOG_H_
+#pragma once
+
+#include <cstddef>
+#include <string>
+#include <utility>
+#include <vector>
+
+#include "base/basictypes.h"
+#include "base/string_piece.h"
+
+namespace logging {
+
+// A helper class containing all the settings for vlogging.
+class VlogInfo {
+ public:
+  // |v_switch| gives the default maximal active V-logging level; 0 is
+  // the default.  Normally positive values are used for V-logging
+  // levels.
+  //
+  // |vmodule_switch| gives the per-module maximal V-logging levels to
+  // override the value given by |v_switch|.
+  // E.g. "my_module=2,foo*=3" would change the logging level for all
+  // code in source files "my_module.*" and "foo*.*" ("-inl" suffixes
+  // are also disregarded for this matching).
+  VlogInfo(const std::string& v_switch,
+           const std::string& vmodule_switch);
+
+  // Returns the vlog level for a given file (usually taken from
+  // __FILE__).
+  int GetVlogLevel(const base::StringPiece& file);
+
+  static const int kDefaultVlogLevel;
+
+ private:
+  typedef std::pair<std::string, int> VmodulePattern;
+
+  int max_vlog_level_;
+  std::vector<VmodulePattern> vmodule_levels_;
+
+  DISALLOW_COPY_AND_ASSIGN(VlogInfo);
+};
+
+}  // namespace logging
+
+#endif  // BASE_VLOG_H_