Repo created

TMessagesProj/jni/voip/webrtc/base/files/file_tracing.h

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+// Copyright 2015 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_FILES_FILE_TRACING_H_
+#define BASE_FILES_FILE_TRACING_H_
+
+#include <stdint.h>
+
+#include "base/base_export.h"
+#include "base/macros.h"
+
+#define FILE_TRACING_PREFIX "File"
+
+#define SCOPED_FILE_TRACE_WITH_SIZE(name, size) \
+    FileTracing::ScopedTrace scoped_file_trace; \
+    if (FileTracing::IsCategoryEnabled()) \
+      scoped_file_trace.Initialize(FILE_TRACING_PREFIX "::" name, this, size)
+
+#define SCOPED_FILE_TRACE(name) SCOPED_FILE_TRACE_WITH_SIZE(name, 0)
+
+namespace base {
+
+class File;
+class FilePath;
+
+class BASE_EXPORT FileTracing {
+ public:
+  // Whether the file tracing category is enabled.
+  static bool IsCategoryEnabled();
+
+  class Provider {
+   public:
+    virtual ~Provider() = default;
+
+    // Whether the file tracing category is currently enabled.
+    virtual bool FileTracingCategoryIsEnabled() const = 0;
+
+    // Enables file tracing for |id|. Must be called before recording events.
+    virtual void FileTracingEnable(const void* id) = 0;
+
+    // Disables file tracing for |id|.
+    virtual void FileTracingDisable(const void* id) = 0;
+
+    // Begins an event for |id| with |name|. |path| tells where in the directory
+    // structure the event is happening (and may be blank). |size| is the number
+    // of bytes involved in the event.
+    virtual void FileTracingEventBegin(const char* name,
+                                       const void* id,
+                                       const FilePath& path,
+                                       int64_t size) = 0;
+
+    // Ends an event for |id| with |name|.
+    virtual void FileTracingEventEnd(const char* name, const void* id) = 0;
+  };
+
+  // Sets a global file tracing provider to query categories and record events.
+  static void SetProvider(Provider* provider);
+
+  // Enables file tracing while in scope.
+  class ScopedEnabler {
+   public:
+    ScopedEnabler();
+    ~ScopedEnabler();
+  };
+
+  class ScopedTrace {
+   public:
+    ScopedTrace();
+    ~ScopedTrace();
+
+    // Called only if the tracing category is enabled. |name| is the name of the
+    // event to trace (e.g. "Read", "Write") and must have an application
+    // lifetime (e.g. static or literal). |file| is the file being traced; must
+    // outlive this class. |size| is the size (in bytes) of this event.
+    void Initialize(const char* name, const File* file, int64_t size);
+
+   private:
+    // The ID of this trace. Based on the |file| passed to |Initialize()|. Must
+    // outlive this class.
+    const void* id_;
+
+    // The name of the event to trace (e.g. "Read", "Write"). Prefixed with
+    // "File".
+    const char* name_;
+
+    DISALLOW_COPY_AND_ASSIGN(ScopedTrace);
+  };
+
+  DISALLOW_COPY_AND_ASSIGN(FileTracing);
+};
+
+}  // namespace base
+
+#endif  // BASE_FILES_FILE_TRACING_H_